7515 lines
259 KiB
Plaintext
7515 lines
259 KiB
Plaintext
\input texinfo @c -*-Texinfo-*-
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@c Copyright (c) 1991 1992 1993 1994 Free Software Foundation, Inc.
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@c UPDATE!! On future updates--
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@c (1) check for new machine-dep cmdline options in
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@c md_parse_option definitions in config/tc-*.c
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@c (2) for platform-specific directives, examine md_pseudo_op
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@c in config/tc-*.c
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@c (3) for object-format specific directives, examine obj_pseudo_op
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@c in config/obj-*.c
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@c (4) portable directives in potable[] in read.c
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@c %**start of header
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@setfilename as.info
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@c ---config---
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@c defaults, config file may override:
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@set have-stabs
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@c ---
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@include asconfig.texi
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@c ---
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@c common OR combinations of conditions
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@ifset AOUT
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@set aout-bout
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@end ifset
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@ifset BOUT
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@set aout-bout
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@end ifset
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@ifset H8/300
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@set H8
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@end ifset
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@ifset H8/500
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@set H8
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@end ifset
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@ifset SH
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@set H8
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@end ifset
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@ifset HPPA
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@set abnormal-separator
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@end ifset
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@c ------------
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@ifset GENERIC
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@settitle Using @value{AS}
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@end ifset
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@ifclear GENERIC
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@settitle Using @value{AS} (@value{TARGET})
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@end ifclear
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@setchapternewpage odd
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@c %**end of header
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@c @smallbook
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@c @set SMALL
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@c WARE! Some of the machine-dependent sections contain tables of machine
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@c instructions. Except in multi-column format, these tables look silly.
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@c Unfortunately, Texinfo doesn't have a general-purpose multi-col format, so
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@c the multi-col format is faked within @example sections.
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@c
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@c Again unfortunately, the natural size that fits on a page, for these tables,
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@c is different depending on whether or not smallbook is turned on.
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@c This matters, because of order: text flow switches columns at each page
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@c break.
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@c
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@c The format faked in this source works reasonably well for smallbook,
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@c not well for the default large-page format. This manual expects that if you
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@c turn on @smallbook, you will also uncomment the "@set SMALL" to enable the
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@c tables in question. You can turn on one without the other at your
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@c discretion, of course.
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@ifinfo
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@set SMALL
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@c the insn tables look just as silly in info files regardless of smallbook,
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@c might as well show 'em anyways.
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@end ifinfo
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@ifinfo
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@format
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START-INFO-DIR-ENTRY
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* As: (as). The GNU assembler.
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END-INFO-DIR-ENTRY
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@end format
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@end ifinfo
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@finalout
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@syncodeindex ky cp
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@ifinfo
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This file documents the GNU Assembler "@value{AS}".
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Copyright (C) 1991, 1992, 1993, 1994 Free Software Foundation, Inc.
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Permission is granted to make and distribute verbatim copies of
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this manual provided the copyright notice and this permission notice
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are preserved on all copies.
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@ignore
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Permission is granted to process this file through Tex and print the
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results, provided the printed document carries copying permission
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notice identical to this one except for the removal of this paragraph
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(this paragraph not being relevant to the printed manual).
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@end ignore
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Permission is granted to copy and distribute modified versions of this manual
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under the conditions for verbatim copying, provided that the entire resulting
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derived work is distributed under the terms of a permission notice identical to
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this one.
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Permission is granted to copy and distribute translations of this manual
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into another language, under the above conditions for modified versions.
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@end ifinfo
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@titlepage
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@title Using @value{AS}
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@subtitle The GNU Assembler
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@ifclear GENERIC
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@subtitle for the @value{TARGET} family
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@end ifclear
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@sp 1
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@subtitle January 1994
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@sp 1
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@sp 13
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The Free Software Foundation Inc. thanks The Nice Computer
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Company of Australia for loaning Dean Elsner to write the
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first (Vax) version of @code{as} for Project GNU.
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The proprietors, management and staff of TNCCA thank FSF for
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distracting the boss while they got some work
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done.
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@sp 3
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@author Dean Elsner, Jay Fenlason & friends
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@page
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@tex
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{\parskip=0pt
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\hfill {\it Using {\tt @value{AS}}}\par
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\hfill Edited by Roland Pesch for Cygnus Support\par
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}
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%"boxit" macro for figures:
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%Modified from Knuth's ``boxit'' macro from TeXbook (answer to exercise 21.3)
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\gdef\boxit#1#2{\vbox{\hrule\hbox{\vrule\kern3pt
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\vbox{\parindent=0pt\parskip=0pt\hsize=#1\kern3pt\strut\hfil
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#2\hfil\strut\kern3pt}\kern3pt\vrule}\hrule}}%box with visible outline
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\gdef\ibox#1#2{\hbox to #1{#2\hfil}\kern8pt}% invisible box
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@end tex
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@vskip 0pt plus 1filll
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Copyright @copyright{} 1991, 1992, 1993, 1994 Free Software Foundation, Inc.
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Permission is granted to make and distribute verbatim copies of
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this manual provided the copyright notice and this permission notice
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are preserved on all copies.
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Permission is granted to copy and distribute modified versions of this manual
|
|
under the conditions for verbatim copying, provided that the entire resulting
|
|
derived work is distributed under the terms of a permission notice identical to
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this one.
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Permission is granted to copy and distribute translations of this manual
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into another language, under the above conditions for modified versions.
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@end titlepage
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@ifinfo
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@node Top
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@top Using @value{AS}
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This file is a user guide to the @sc{gnu} assembler @code{@value{AS}}.
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@ifclear GENERIC
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This version of the file describes @code{@value{AS}} configured to generate
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code for @value{TARGET} architectures.
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@end ifclear
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@menu
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* Overview:: Overview
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* Invoking:: Command-Line Options
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* Syntax:: Syntax
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* Sections:: Sections and Relocation
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* Symbols:: Symbols
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* Expressions:: Expressions
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* Pseudo Ops:: Assembler Directives
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* Machine Dependencies:: Machine Dependent Features
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* Acknowledgements:: Who Did What
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* Index:: Index
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@end menu
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@end ifinfo
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@node Overview
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@chapter Overview
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@iftex
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This manual is a user guide to the @sc{gnu} assembler @code{@value{AS}}.
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@ifclear GENERIC
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This version of the manual describes @code{@value{AS}} configured to generate
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code for @value{TARGET} architectures.
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@end ifclear
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@end iftex
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@cindex invocation summary
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@cindex option summary
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@cindex summary of options
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Here is a brief summary of how to invoke @code{@value{AS}}. For details,
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@pxref{Invoking,,Comand-Line Options}.
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@c We don't use deffn and friends for the following because they seem
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@c to be limited to one line for the header.
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@smallexample
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@value{AS} [ -a[dhlns] ] [ -D ] [ -f ] [ --help ]
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[ -I @var{dir} ] [ -J ] [ -K ] [ -L ] [ -o @var{objfile} ]
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[ -R ] [ --statistics ] [ -v ] [ -version ] [ --version ]
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[ -W ] [ -w ] [ -x ] [ -Z ]
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@ifset A29K
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@c am29k has no machine-dependent assembler options
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@end ifset
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@ifset H8
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@c Hitachi family chips have no machine-dependent assembler options
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@end ifset
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@ifset HPPA
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@c HPPA has no machine-dependent assembler options (yet).
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@end ifset
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@ifset SPARC
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[ -Av6 | -Av7 | -Av8 | -Av9 | -Asparclite | -bump ]
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@end ifset
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@ifset Z8000
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@c Z8000 has no machine-dependent assembler options
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@end ifset
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@ifset I960
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@c see md_parse_option in tc-i960.c
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[ -ACA | -ACA_A | -ACB | -ACC | -AKA | -AKB | -AKC | -AMC ]
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[ -b ] [ -no-relax ]
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@end ifset
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@ifset M680X0
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[ -l ] [ -m68000 | -m68010 | -m68020 | ... ]
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@end ifset
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@ifset MIPS
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[ -nocpp ] [ -EL ] [ -EB ] [ -G @var{num} ] [ -mcpu=@var{CPU} ]
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[ -mips1 ] [ -mips2 ] [ -mips3 ] [ -m4650 ] [ -no-m4650 ]
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[ --trap ] [ --break ]
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@end ifset
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[ -- | @var{files} @dots{} ]
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@end smallexample
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@table @code
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@item -a[dhlns]
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Turn on listings, in any of a variety of ways:
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@table @code
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@item -ad
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omit debugging directives
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@item -ah
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include high-level source
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@item -al
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include assembly
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@item -an
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omit forms processing
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@item -as
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include symbols
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@end table
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You may combine these options; for example, use @samp{-aln} for assembly
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listing without forms processing. By itself, @samp{-a} defaults to
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@samp{-ahls}---that is, all listings turned on.
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@item -D
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Ignored. This option is accepted for script compatibility with calls to
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other assemblers.
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@item -f
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``fast''---skip whitespace and comment preprocessing (assume source is
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compiler output).
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@item --help
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Print a summary of the command line options and exit.
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@item -I @var{dir}
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Add directory @var{dir} to the search list for @code{.include} directives.
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@item -J
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Don't warn about signed overflow.
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@item -K
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@ifclear DIFF-TBL-KLUGE
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This option is accepted but has no effect on the @value{TARGET} family.
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@end ifclear
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@ifset DIFF-TBL-KLUGE
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Issue warnings when difference tables altered for long displacements.
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@end ifset
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@item -L
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Keep (in the symbol table) local symbols, starting with @samp{L}.
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@item -o @var{objfile}
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Name the object-file output from @code{@value{AS}} @var{objfile}.
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@item -R
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Fold the data section into the text section.
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@item --statistics
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Print the maximum space (in bytes) and total time (in seconds) used by
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assembly.
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@item -v
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@itemx -version
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Print the @code{as} version.
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@item --version
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Print the @code{as} version and exit.
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@item -W
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Suppress warning messages.
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@item -w
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Ignored.
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@item -x
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Ignored.
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@item -Z
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Generate an object file even after errors.
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@item -- | @var{files} @dots{}
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Standard input, or source files to assemble.
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@end table
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@ifset I960
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The following options are available when @value{AS} is configured for the
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Intel 80960 processor.
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@table @code
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@item -ACA | -ACA_A | -ACB | -ACC | -AKA | -AKB | -AKC | -AMC
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Specify which variant of the 960 architecture is the target.
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@item -b
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Add code to collect statistics about branches taken.
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@item -no-relax
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Do not alter compare-and-branch instructions for long displacements;
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error if necessary.
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@end table
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@end ifset
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|
@ifset M680X0
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The following options are available when @value{AS} is configured for the
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Motorola 68000 series.
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@table @code
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@item -l
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Shorten references to undefined symbols, to one word instead of two.
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@item -m68000 | -m68008 | -m68010 | -m68020 | -m68030 | -m68040
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@itemx | -m68302 | -m68331 | -m68332 | -m68333 | -m68340 | -mcpu32
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Specify what processor in the 68000 family is the target. The default
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is normally the 68020, but this can be changed at configuration time.
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@item -m68881 | -m68882 | -mno-68881 | -mno-68882
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The target machine does (or does not) have a floating-point coprocessor.
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The default is to assume a coprocessor for 68020, 68030, and cpu32. Although
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the basic 68000 is not compatible with the 68881, a combination of the
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two can be specified, since it's possible to do emulation of the
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coprocessor instructions with the main processor.
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@item -m68851 | -mno-68851
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The target machine does (or does not) have a memory-management
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unit coprocessor. The default is to assume an MMU for 68020 and up.
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@end table
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@end ifset
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@ifset SPARC
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The following options are available when @code{@value{AS}} is configured
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for the SPARC architecture:
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@table @code
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@item -Av6 | -Av7 | -Av8 | -Av9 | -Asparclite
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Explicitly select a variant of the SPARC architecture.
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@item -bump
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Warn when the assembler switches to another architecture.
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@end table
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@end ifset
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@ifset MIPS
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The following options are available when @value{AS} is configured for
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a MIPS processor.
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@table @code
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@item -G @var{num}
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This option sets the largest size of an object that can be referenced
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implicitly with the @code{gp} register. It is only accepted for targets that
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use ECOFF format, such as a DECstation running Ultrix. The default value is 8.
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@cindex MIPS endianness
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@cindex endianness, MIPS
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@cindex big endian output, MIPS
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@item -EB
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Generate ``big endian'' format output.
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@cindex little endian output, MIPS
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@item -EL
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Generate ``little endian'' format output.
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@cindex MIPS ISA
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@item -mips1
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@itemx -mips2
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@itemx -mips3
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Generate code for a particular MIPS Instruction Set Architecture level.
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@samp{-mips1} corresponds to the @sc{r2000} and @sc{r3000} processors,
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@samp{-mips2} to the @sc{r6000} processor, and @samp{-mips3} to the @sc{r4000}
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processor.
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@item -m4650
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@item -no-m4650
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|
Generate code for the MIPS @sc{r4650} chip. This tells the assembler to accept
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the @samp{mad} and @samp{madu} instruction, and to not schedule @samp{nop}
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instructions around accesses to the @samp{HI} and @samp{LO} registers.
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@samp{-no-m4650} turns off this option.
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@item -mcpu=@var{CPU}
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|
Generate code for a particular MIPS cpu. This has little effect on the
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assembler, but it is passed by @code{@value{GCC}}.
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|
@item -nocpp
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@code{@value{AS}} ignores this option. It is accepted for compatibility with
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the native tools.
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|
@item --trap
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@itemx --no-trap
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|
@itemx --break
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|
@itemx --no-break
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|
Control how to deal with multiplication overflow and division by zero.
|
|
@samp{--trap} or @samp{--no-break} (which are synonyms) take a trap exception
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|
(and only work for Instruction Set Architecture level 2 and higher);
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|
@samp{--break} or @samp{--no-trap} (also synonyms, and the default) take a
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break exception.
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@end table
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|
@end ifset
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|
|
|
@menu
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|
* Manual:: Structure of this Manual
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|
* GNU Assembler:: @value{AS}, the GNU Assembler
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|
* Object Formats:: Object File Formats
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|
* Command Line:: Command Line
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|
* Input Files:: Input Files
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|
* Object:: Output (Object) File
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|
* Errors:: Error and Warning Messages
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|
@end menu
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|
|
|
@node Manual
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|
@section Structure of this Manual
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|
|
|
@cindex manual, structure and purpose
|
|
This manual is intended to describe what you need to know to use
|
|
@sc{gnu} @code{@value{AS}}. We cover the syntax expected in source files, including
|
|
notation for symbols, constants, and expressions; the directives that
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|
@code{@value{AS}} understands; and of course how to invoke @code{@value{AS}}.
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|
|
|
@ifclear GENERIC
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|
We also cover special features in the @value{TARGET}
|
|
configuration of @code{@value{AS}}, including assembler directives.
|
|
@end ifclear
|
|
@ifset GENERIC
|
|
This manual also describes some of the machine-dependent features of
|
|
various flavors of the assembler.
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|
@end ifset
|
|
|
|
@cindex machine instructions (not covered)
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|
On the other hand, this manual is @emph{not} intended as an introduction
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|
to programming in assembly language---let alone programming in general!
|
|
In a similar vein, we make no attempt to introduce the machine
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|
architecture; we do @emph{not} describe the instruction set, standard
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|
mnemonics, registers or addressing modes that are standard to a
|
|
particular architecture.
|
|
@ifset GENERIC
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|
You may want to consult the manufacturer's
|
|
machine architecture manual for this information.
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|
@end ifset
|
|
@ifclear GENERIC
|
|
@ifset H8/300
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|
For information on the H8/300 machine instruction set, see @cite{H8/300
|
|
Series Programming Manual} (Hitachi ADE--602--025). For the H8/300H,
|
|
see @cite{H8/300H Series Programming Manual} (Hitachi).
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|
@end ifset
|
|
@ifset H8/500
|
|
For information on the H8/500 machine instruction set, see @cite{H8/500
|
|
Series Programming Manual} (Hitachi M21T001).
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|
@end ifset
|
|
@ifset SH
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|
For information on the Hitachi SH machine instruction set, see
|
|
@cite{SH-Microcomputer User's Manual} (Hitachi Micro Systems, Inc.).
|
|
@end ifset
|
|
@ifset Z8000
|
|
For information on the Z8000 machine instruction set, see @cite{Z8000 CPU Technical Manual}
|
|
@end ifset
|
|
@end ifclear
|
|
|
|
@c I think this is premature---pesch@cygnus.com, 17jan1991
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|
@ignore
|
|
Throughout this manual, we assume that you are running @dfn{GNU},
|
|
the portable operating system from the @dfn{Free Software
|
|
Foundation, Inc.}. This restricts our attention to certain kinds of
|
|
computer (in particular, the kinds of computers that @sc{gnu} can run on);
|
|
once this assumption is granted examples and definitions need less
|
|
qualification.
|
|
|
|
@code{@value{AS}} is part of a team of programs that turn a high-level
|
|
human-readable series of instructions into a low-level
|
|
computer-readable series of instructions. Different versions of
|
|
@code{@value{AS}} are used for different kinds of computer.
|
|
@end ignore
|
|
|
|
@c There used to be a section "Terminology" here, which defined
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|
@c "contents", "byte", "word", and "long". Defining "word" to any
|
|
@c particular size is confusing when the .word directive may generate 16
|
|
@c bits on one machine and 32 bits on another; in general, for the user
|
|
@c version of this manual, none of these terms seem essential to define.
|
|
@c They were used very little even in the former draft of the manual;
|
|
@c this draft makes an effort to avoid them (except in names of
|
|
@c directives).
|
|
|
|
@node GNU Assembler
|
|
@section @value{AS}, the GNU Assembler
|
|
|
|
@sc{gnu} @code{as} is really a family of assemblers.
|
|
@ifclear GENERIC
|
|
This manual describes @code{@value{AS}}, a member of that family which is
|
|
configured for the @value{TARGET} architectures.
|
|
@end ifclear
|
|
If you use (or have used) the @sc{gnu} assembler on one architecture, you
|
|
should find a fairly similar environment when you use it on another
|
|
architecture. Each version has much in common with the others,
|
|
including object file formats, most assembler directives (often called
|
|
@dfn{pseudo-ops}) and assembler syntax.@refill
|
|
|
|
@cindex purpose of @sc{gnu} @code{@value{AS}}
|
|
@code{@value{AS}} is primarily intended to assemble the output of the
|
|
@sc{gnu} C compiler @code{@value{GCC}} for use by the linker
|
|
@code{@value{LD}}. Nevertheless, we've tried to make @code{@value{AS}}
|
|
assemble correctly everything that other assemblers for the same
|
|
machine would assemble.
|
|
@ifset VAX
|
|
Any exceptions are documented explicitly (@pxref{Machine Dependencies}).
|
|
@end ifset
|
|
@ifset M680X0
|
|
@c This remark should appear in generic version of manual; assumption
|
|
@c here is that generic version sets M680x0.
|
|
This doesn't mean @code{@value{AS}} always uses the same syntax as another
|
|
assembler for the same architecture; for example, we know of several
|
|
incompatible versions of 680x0 assembly language syntax.
|
|
@end ifset
|
|
|
|
Unlike older assemblers, @code{@value{AS}} is designed to assemble a source
|
|
program in one pass of the source file. This has a subtle impact on the
|
|
@kbd{.org} directive (@pxref{Org,,@code{.org}}).
|
|
|
|
@node Object Formats
|
|
@section Object File Formats
|
|
|
|
@cindex object file format
|
|
The @sc{gnu} assembler can be configured to produce several alternative
|
|
object file formats. For the most part, this does not affect how you
|
|
write assembly language programs; but directives for debugging symbols
|
|
are typically different in different file formats. @xref{Symbol
|
|
Attributes,,Symbol Attributes}.
|
|
@ifclear GENERIC
|
|
@ifclear MULTI-OBJ
|
|
On the @value{TARGET}, @code{@value{AS}} is configured to produce
|
|
@value{OBJ-NAME} format object files.
|
|
@end ifclear
|
|
@c The following should exhaust all configs that set MULTI-OBJ, ideally
|
|
@ifset A29K
|
|
On the @value{TARGET}, @code{@value{AS}} can be configured to produce either
|
|
@code{a.out} or COFF format object files.
|
|
@end ifset
|
|
@ifset I960
|
|
On the @value{TARGET}, @code{@value{AS}} can be configured to produce either
|
|
@code{b.out} or COFF format object files.
|
|
@end ifset
|
|
@ifset HPPA
|
|
On the @value{TARGET}, @code{@value{AS}} can be configured to produce either
|
|
SOM or ELF format object files.
|
|
@end ifset
|
|
@end ifclear
|
|
|
|
@node Command Line
|
|
@section Command Line
|
|
|
|
@cindex command line conventions
|
|
After the program name @code{@value{AS}}, the command line may contain
|
|
options and file names. Options may appear in any order, and may be
|
|
before, after, or between file names. The order of file names is
|
|
significant.
|
|
|
|
@cindex standard input, as input file
|
|
@kindex --
|
|
@file{--} (two hyphens) by itself names the standard input file
|
|
explicitly, as one of the files for @code{@value{AS}} to assemble.
|
|
|
|
@cindex options, command line
|
|
Except for @samp{--} any command line argument that begins with a
|
|
hyphen (@samp{-}) is an option. Each option changes the behavior of
|
|
@code{@value{AS}}. No option changes the way another option works. An
|
|
option is a @samp{-} followed by one or more letters; the case of
|
|
the letter is important. All options are optional.
|
|
|
|
Some options expect exactly one file name to follow them. The file
|
|
name may either immediately follow the option's letter (compatible
|
|
with older assemblers) or it may be the next command argument (@sc{gnu}
|
|
standard). These two command lines are equivalent:
|
|
|
|
@smallexample
|
|
@value{AS} -o my-object-file.o mumble.s
|
|
@value{AS} -omy-object-file.o mumble.s
|
|
@end smallexample
|
|
|
|
@node Input Files
|
|
@section Input Files
|
|
|
|
@cindex input
|
|
@cindex source program
|
|
@cindex files, input
|
|
We use the phrase @dfn{source program}, abbreviated @dfn{source}, to
|
|
describe the program input to one run of @code{@value{AS}}. The program may
|
|
be in one or more files; how the source is partitioned into files
|
|
doesn't change the meaning of the source.
|
|
|
|
@c I added "con" prefix to "catenation" just to prove I can overcome my
|
|
@c APL training... pesch@cygnus.com
|
|
The source program is a concatenation of the text in all the files, in the
|
|
order specified.
|
|
|
|
Each time you run @code{@value{AS}} it assembles exactly one source
|
|
program. The source program is made up of one or more files.
|
|
(The standard input is also a file.)
|
|
|
|
You give @code{@value{AS}} a command line that has zero or more input file
|
|
names. The input files are read (from left file name to right). A
|
|
command line argument (in any position) that has no special meaning
|
|
is taken to be an input file name.
|
|
|
|
If you give @code{@value{AS}} no file names it attempts to read one input file
|
|
from the @code{@value{AS}} standard input, which is normally your terminal. You
|
|
may have to type @key{ctl-D} to tell @code{@value{AS}} there is no more program
|
|
to assemble.
|
|
|
|
Use @samp{--} if you need to explicitly name the standard input file
|
|
in your command line.
|
|
|
|
If the source is empty, @code{@value{AS}} produces a small, empty object
|
|
file.
|
|
|
|
@subheading Filenames and Line-numbers
|
|
|
|
@cindex input file linenumbers
|
|
@cindex line numbers, in input files
|
|
There are two ways of locating a line in the input file (or files) and
|
|
either may be used in reporting error messages. One way refers to a line
|
|
number in a physical file; the other refers to a line number in a
|
|
``logical'' file. @xref{Errors, ,Error and Warning Messages}.
|
|
|
|
@dfn{Physical files} are those files named in the command line given
|
|
to @code{@value{AS}}.
|
|
|
|
@dfn{Logical files} are simply names declared explicitly by assembler
|
|
directives; they bear no relation to physical files. Logical file names
|
|
help error messages reflect the original source file, when @code{@value{AS}}
|
|
source is itself synthesized from other files.
|
|
@xref{App-File,,@code{.app-file}}.
|
|
|
|
@node Object
|
|
@section Output (Object) File
|
|
|
|
@cindex object file
|
|
@cindex output file
|
|
@kindex a.out
|
|
@kindex .o
|
|
Every time you run @code{@value{AS}} it produces an output file, which is
|
|
your assembly language program translated into numbers. This file
|
|
is the object file. Its default name is
|
|
@ifclear BOUT
|
|
@code{a.out}.
|
|
@end ifclear
|
|
@ifset BOUT
|
|
@ifset GENERIC
|
|
@code{a.out}, or
|
|
@end ifset
|
|
@code{b.out} when @code{@value{AS}} is configured for the Intel 80960.
|
|
@end ifset
|
|
You can give it another name by using the @code{-o} option. Conventionally,
|
|
object file names end with @file{.o}. The default name is used for historical
|
|
reasons: older assemblers were capable of assembling self-contained programs
|
|
directly into a runnable program. (For some formats, this isn't currently
|
|
possible, but it can be done for the @code{a.out} format.)
|
|
|
|
@cindex linker
|
|
@kindex ld
|
|
The object file is meant for input to the linker @code{@value{LD}}. It contains
|
|
assembled program code, information to help @code{@value{LD}} integrate
|
|
the assembled program into a runnable file, and (optionally) symbolic
|
|
information for the debugger.
|
|
|
|
@c link above to some info file(s) like the description of a.out.
|
|
@c don't forget to describe GNU info as well as Unix lossage.
|
|
|
|
@node Errors
|
|
@section Error and Warning Messages
|
|
|
|
@cindex error messsages
|
|
@cindex warning messages
|
|
@cindex messages from @code{@value{AS}}
|
|
@code{@value{AS}} may write warnings and error messages to the standard error
|
|
file (usually your terminal). This should not happen when a compiler
|
|
runs @code{@value{AS}} automatically. Warnings report an assumption made so
|
|
that @code{@value{AS}} could keep assembling a flawed program; errors report a
|
|
grave problem that stops the assembly.
|
|
|
|
@cindex format of warning messages
|
|
Warning messages have the format
|
|
|
|
@smallexample
|
|
file_name:@b{NNN}:Warning Message Text
|
|
@end smallexample
|
|
|
|
@noindent
|
|
@cindex line numbers, in warnings/errors
|
|
(where @b{NNN} is a line number). If a logical file name has been given
|
|
(@pxref{App-File,,@code{.app-file}}) it is used for the filename,
|
|
otherwise the name of the current input file is used. If a logical line
|
|
number was given
|
|
@ifset GENERIC
|
|
(@pxref{Line,,@code{.line}})
|
|
@end ifset
|
|
@ifclear GENERIC
|
|
@ifclear A29K
|
|
(@pxref{Line,,@code{.line}})
|
|
@end ifclear
|
|
@ifset A29K
|
|
(@pxref{Ln,,@code{.ln}})
|
|
@end ifset
|
|
@end ifclear
|
|
then it is used to calculate the number printed,
|
|
otherwise the actual line in the current source file is printed. The
|
|
message text is intended to be self explanatory (in the grand Unix
|
|
tradition).
|
|
|
|
@cindex format of error messages
|
|
Error messages have the format
|
|
@smallexample
|
|
file_name:@b{NNN}:FATAL:Error Message Text
|
|
@end smallexample
|
|
The file name and line number are derived as for warning
|
|
messages. The actual message text may be rather less explanatory
|
|
because many of them aren't supposed to happen.
|
|
|
|
@node Invoking
|
|
@chapter Command-Line Options
|
|
|
|
@cindex options, all versions of @code{@value{AS}}
|
|
This chapter describes command-line options available in @emph{all}
|
|
versions of the @sc{gnu} assembler; @pxref{Machine Dependencies}, for options specific
|
|
@ifclear GENERIC
|
|
to the @value{TARGET}.
|
|
@end ifclear
|
|
@ifset GENERIC
|
|
to particular machine architectures.
|
|
@end ifset
|
|
|
|
If you are invoking @code{@value{AS}} via the @sc{gnu} C compiler (version 2), you
|
|
can use the @samp{-Wa} option to pass arguments through to the
|
|
assembler. The assembler arguments must be separated from each other
|
|
(and the @samp{-Wa}) by commas. For example:
|
|
|
|
@smallexample
|
|
gcc -c -g -O -Wa,-alh,-L file.c
|
|
@end smallexample
|
|
|
|
@noindent
|
|
emits a listing to standard output with high-level
|
|
and assembly source.
|
|
|
|
Usually you do not need to use this @samp{-Wa} mechanism, since many compiler
|
|
command-line options are automatically passed to the assembler by the compiler.
|
|
(You can call the @sc{gnu} compiler driver with the @samp{-v} option to see
|
|
precisely what options it passes to each compilation pass, including the
|
|
assembler.)
|
|
|
|
@menu
|
|
* a:: -a[dhlns] enable listings
|
|
* D:: -D for compatibility
|
|
* f:: -f to work faster
|
|
* I:: -I for .include search path
|
|
@ifclear DIFF-TBL-KLUGE
|
|
* K:: -K for compatibility
|
|
@end ifclear
|
|
@ifset DIFF-TBL-KLUGE
|
|
* K:: -K for difference tables
|
|
@end ifset
|
|
|
|
* L:: -L to retain local labels
|
|
* o:: -o to name the object file
|
|
* R:: -R to join data and text sections
|
|
* statistics:: --statistics to see statistics about assembly
|
|
* v:: -v to announce version
|
|
* W:: -W to suppress warnings
|
|
* Z:: -Z to make object file even after errors
|
|
@end menu
|
|
|
|
@node a
|
|
@section Enable Listings: @code{-a[dhlns]}
|
|
|
|
@kindex -a
|
|
@kindex -ad
|
|
@kindex -ah
|
|
@kindex -al
|
|
@kindex -an
|
|
@kindex -as
|
|
@cindex listings, enabling
|
|
@cindex assembly listings, enabling
|
|
|
|
These options enable listing output from the assembler. By itself,
|
|
@samp{-a} requests high-level, assembly, and symbols listing.
|
|
You can use other letters to select specific options for the list:
|
|
@samp{-ah} requests a high-level language listing,
|
|
@samp{-al} requests an output-program assembly listing, and
|
|
@samp{-as} requests a symbol table listing.
|
|
High-level listings require that a compiler debugging option like
|
|
@samp{-g} be used, and that assembly listings (@samp{-al}) be requested
|
|
also.
|
|
|
|
Use the @samp{-ad} option to omit debugging directives from the
|
|
listing.
|
|
|
|
Once you have specified one of these options, you can further control
|
|
listing output and its appearance using the directives @code{.list},
|
|
@code{.nolist}, @code{.psize}, @code{.eject}, @code{.title}, and
|
|
@code{.sbttl}.
|
|
The @samp{-an} option turns off all forms processing.
|
|
If you do not request listing output with one of the @samp{-a} options, the
|
|
listing-control directives have no effect.
|
|
|
|
The letters after @samp{-a} may be combined into one option,
|
|
@emph{e.g.}, @samp{-aln}.
|
|
|
|
@node D
|
|
@section @code{-D}
|
|
|
|
@kindex -D
|
|
This option has no effect whatsoever, but it is accepted to make it more
|
|
likely that scripts written for other assemblers also work with
|
|
@code{@value{AS}}.
|
|
|
|
@node f
|
|
@section Work Faster: @code{-f}
|
|
|
|
@kindex -f
|
|
@cindex trusted compiler
|
|
@cindex faster processing (@code{-f})
|
|
@samp{-f} should only be used when assembling programs written by a
|
|
(trusted) compiler. @samp{-f} stops the assembler from doing whitespace
|
|
and comment preprocessing on
|
|
the input file(s) before assembling them. @xref{Preprocessing,
|
|
,Preprocessing}.
|
|
|
|
@quotation
|
|
@emph{Warning:} if you use @samp{-f} when the files actually need to be
|
|
preprocessed (if they contain comments, for example), @code{@value{AS}} does
|
|
not work correctly.
|
|
@end quotation
|
|
|
|
@node I
|
|
@section @code{.include} search path: @code{-I} @var{path}
|
|
|
|
@kindex -I @var{path}
|
|
@cindex paths for @code{.include}
|
|
@cindex search path for @code{.include}
|
|
@cindex @code{include} directive search path
|
|
Use this option to add a @var{path} to the list of directories
|
|
@code{@value{AS}} searches for files specified in @code{.include}
|
|
directives (@pxref{Include,,@code{.include}}). You may use @code{-I} as
|
|
many times as necessary to include a variety of paths. The current
|
|
working directory is always searched first; after that, @code{@value{AS}}
|
|
searches any @samp{-I} directories in the same order as they were
|
|
specified (left to right) on the command line.
|
|
|
|
@node K
|
|
@section Difference Tables: @code{-K}
|
|
|
|
@kindex -K
|
|
@ifclear DIFF-TBL-KLUGE
|
|
On the @value{TARGET} family, this option is allowed, but has no effect. It is
|
|
permitted for compatibility with the @sc{gnu} assembler on other platforms,
|
|
where it can be used to warn when the assembler alters the machine code
|
|
generated for @samp{.word} directives in difference tables. The @value{TARGET}
|
|
family does not have the addressing limitations that sometimes lead to this
|
|
alteration on other platforms.
|
|
@end ifclear
|
|
|
|
@ifset DIFF-TBL-KLUGE
|
|
@cindex difference tables, warning
|
|
@cindex warning for altered difference tables
|
|
@code{@value{AS}} sometimes alters the code emitted for directives of the form
|
|
@samp{.word @var{sym1}-@var{sym2}}; @pxref{Word,,@code{.word}}.
|
|
You can use the @samp{-K} option if you want a warning issued when this
|
|
is done.
|
|
@end ifset
|
|
|
|
@node L
|
|
@section Include Local Labels: @code{-L}
|
|
|
|
@kindex -L
|
|
@cindex local labels, retaining in output
|
|
Labels beginning with @samp{L} (upper case only) are called @dfn{local
|
|
labels}. @xref{Symbol Names}. Normally you do not see such labels when
|
|
debugging, because they are intended for the use of programs (like
|
|
compilers) that compose assembler programs, not for your notice.
|
|
Normally both @code{@value{AS}} and @code{@value{LD}} discard such labels, so you do not
|
|
normally debug with them.
|
|
|
|
This option tells @code{@value{AS}} to retain those @samp{L@dots{}} symbols
|
|
in the object file. Usually if you do this you also tell the linker
|
|
@code{@value{LD}} to preserve symbols whose names begin with @samp{L}.
|
|
|
|
By default, a local label is any label beginning with @samp{L}, but each
|
|
target is allowed to redefine the local label prefix.
|
|
@ifset HPPA
|
|
On the HPPA local labels begin with @samp{L$}.
|
|
@end ifset
|
|
|
|
@node o
|
|
@section Name the Object File: @code{-o}
|
|
|
|
@kindex -o
|
|
@cindex naming object file
|
|
@cindex object file name
|
|
There is always one object file output when you run @code{@value{AS}}. By
|
|
default it has the name
|
|
@ifset GENERIC
|
|
@ifset I960
|
|
@file{a.out} (or @file{b.out}, for Intel 960 targets only).
|
|
@end ifset
|
|
@ifclear I960
|
|
@file{a.out}.
|
|
@end ifclear
|
|
@end ifset
|
|
@ifclear GENERIC
|
|
@ifset I960
|
|
@file{b.out}.
|
|
@end ifset
|
|
@ifclear I960
|
|
@file{a.out}.
|
|
@end ifclear
|
|
@end ifclear
|
|
You use this option (which takes exactly one filename) to give the
|
|
object file a different name.
|
|
|
|
Whatever the object file is called, @code{@value{AS}} overwrites any
|
|
existing file of the same name.
|
|
|
|
@node R
|
|
@section Join Data and Text Sections: @code{-R}
|
|
|
|
@kindex -R
|
|
@cindex data and text sections, joining
|
|
@cindex text and data sections, joining
|
|
@cindex joining text and data sections
|
|
@cindex merging text and data sections
|
|
@code{-R} tells @code{@value{AS}} to write the object file as if all
|
|
data-section data lives in the text section. This is only done at
|
|
the very last moment: your binary data are the same, but data
|
|
section parts are relocated differently. The data section part of
|
|
your object file is zero bytes long because all its bytes are
|
|
appended to the text section. (@xref{Sections,,Sections and Relocation}.)
|
|
|
|
When you specify @code{-R} it would be possible to generate shorter
|
|
address displacements (because we do not have to cross between text and
|
|
data section). We refrain from doing this simply for compatibility with
|
|
older versions of @code{@value{AS}}. In future, @code{-R} may work this way.
|
|
|
|
@ifset COFF
|
|
When @code{@value{AS}} is configured for COFF output,
|
|
this option is only useful if you use sections named @samp{.text} and
|
|
@samp{.data}.
|
|
@end ifset
|
|
|
|
@ifset HPPA
|
|
@code{-R} is not supported for any of the HPPA targets. Using
|
|
@code{-R} generates a warning from @code{@value{AS}}.
|
|
@end ifset
|
|
|
|
@node statistics
|
|
@section Display Assembly Statistics: @code{--statistics}
|
|
|
|
@kindex --statistics
|
|
@cindex statistics, about assembly
|
|
@cindex time, total for assembly
|
|
@cindex space used, maximum for assembly
|
|
Use @samp{--statistics} to display two statistics about the resources used by
|
|
@code{@value{AS}}: the maximum amount of space allocated during the assembly
|
|
(in bytes), and the total execution time taken for the assembly (in @sc{cpu}
|
|
seconds).
|
|
|
|
@node v
|
|
@section Announce Version: @code{-v}
|
|
|
|
@kindex -v
|
|
@kindex -version
|
|
@cindex @code{@value{AS}} version
|
|
@cindex version of @code{@value{AS}}
|
|
You can find out what version of as is running by including the
|
|
option @samp{-v} (which you can also spell as @samp{-version}) on the
|
|
command line.
|
|
|
|
@node W
|
|
@section Suppress Warnings: @code{-W}
|
|
|
|
@kindex -W
|
|
@cindex suppressing warnings
|
|
@cindex warnings, suppressing
|
|
@code{@value{AS}} should never give a warning or error message when
|
|
assembling compiler output. But programs written by people often
|
|
cause @code{@value{AS}} to give a warning that a particular assumption was
|
|
made. All such warnings are directed to the standard error file.
|
|
If you use this option, no warnings are issued. This option only
|
|
affects the warning messages: it does not change any particular of how
|
|
@code{@value{AS}} assembles your file. Errors, which stop the assembly, are
|
|
still reported.
|
|
|
|
@node Z
|
|
@section Generate Object File in Spite of Errors: @code{-Z}
|
|
@cindex object file, after errors
|
|
@cindex errors, continuing after
|
|
After an error message, @code{@value{AS}} normally produces no output. If for
|
|
some reason you are interested in object file output even after
|
|
@code{@value{AS}} gives an error message on your program, use the @samp{-Z}
|
|
option. If there are any errors, @code{@value{AS}} continues anyways, and
|
|
writes an object file after a final warning message of the form @samp{@var{n}
|
|
errors, @var{m} warnings, generating bad object file.}
|
|
|
|
@node Syntax
|
|
@chapter Syntax
|
|
|
|
@cindex machine-independent syntax
|
|
@cindex syntax, machine-independent
|
|
This chapter describes the machine-independent syntax allowed in a
|
|
source file. @code{@value{AS}} syntax is similar to what many other
|
|
assemblers use; it is inspired by the BSD 4.2
|
|
@ifclear VAX
|
|
assembler.
|
|
@end ifclear
|
|
@ifset VAX
|
|
assembler, except that @code{@value{AS}} does not assemble Vax bit-fields.
|
|
@end ifset
|
|
|
|
@menu
|
|
* Preprocessing:: Preprocessing
|
|
* Whitespace:: Whitespace
|
|
* Comments:: Comments
|
|
* Symbol Intro:: Symbols
|
|
* Statements:: Statements
|
|
* Constants:: Constants
|
|
@end menu
|
|
|
|
@node Preprocessing
|
|
@section Preprocessing
|
|
|
|
@cindex preprocessing
|
|
The @code{@value{AS}} internal preprocessor:
|
|
@itemize @bullet
|
|
@cindex whitespace, removed by preprocessor
|
|
@item
|
|
adjusts and removes extra whitespace. It leaves one space or tab before
|
|
the keywords on a line, and turns any other whitespace on the line into
|
|
a single space.
|
|
|
|
@cindex comments, removed by preprocessor
|
|
@item
|
|
removes all comments, replacing them with a single space, or an
|
|
appropriate number of newlines.
|
|
|
|
@cindex constants, converted by preprocessor
|
|
@item
|
|
converts character constants into the appropriate numeric values.
|
|
@end itemize
|
|
|
|
It does not do macro processing, include file handling, or
|
|
anything else you may get from your C compiler's preprocessor. You can
|
|
do include file processing with the @code{.include} directive
|
|
(@pxref{Include,,@code{.include}}). You can use the @sc{gnu} C compiler driver
|
|
to get other ``CPP'' style preprocessing, by giving the input file a
|
|
@samp{.S} suffix. @xref{Overall Options,, Options Controlling the Kind of
|
|
Output, gcc.info, Using GNU CC}.
|
|
|
|
Excess whitespace, comments, and character constants
|
|
cannot be used in the portions of the input text that are not
|
|
preprocessed.
|
|
|
|
@cindex turning preprocessing on and off
|
|
@cindex preprocessing, turning on and off
|
|
@kindex #NO_APP
|
|
@kindex #APP
|
|
If the first line of an input file is @code{#NO_APP} or if you use the
|
|
@samp{-f} option, whitespace and comments are not removed from the input file.
|
|
Within an input file, you can ask for whitespace and comment removal in
|
|
specific portions of the by putting a line that says @code{#APP} before the
|
|
text that may contain whitespace or comments, and putting a line that says
|
|
@code{#NO_APP} after this text. This feature is mainly intend to support
|
|
@code{asm} statements in compilers whose output is otherwise free of comments
|
|
and whitespace.
|
|
|
|
@node Whitespace
|
|
@section Whitespace
|
|
|
|
@cindex whitespace
|
|
@dfn{Whitespace} is one or more blanks or tabs, in any order.
|
|
Whitespace is used to separate symbols, and to make programs neater for
|
|
people to read. Unless within character constants
|
|
(@pxref{Characters,,Character Constants}), any whitespace means the same
|
|
as exactly one space.
|
|
|
|
@node Comments
|
|
@section Comments
|
|
|
|
@cindex comments
|
|
There are two ways of rendering comments to @code{@value{AS}}. In both
|
|
cases the comment is equivalent to one space.
|
|
|
|
Anything from @samp{/*} through the next @samp{*/} is a comment.
|
|
This means you may not nest these comments.
|
|
|
|
@smallexample
|
|
/*
|
|
The only way to include a newline ('\n') in a comment
|
|
is to use this sort of comment.
|
|
*/
|
|
|
|
/* This sort of comment does not nest. */
|
|
@end smallexample
|
|
|
|
@cindex line comment character
|
|
Anything from the @dfn{line comment} character to the next newline
|
|
is considered a comment and is ignored. The line comment character is
|
|
@ifset VAX
|
|
@samp{#} on the Vax;
|
|
@end ifset
|
|
@ifset I960
|
|
@samp{#} on the i960;
|
|
@end ifset
|
|
@ifset SPARC
|
|
@samp{!} on the SPARC;
|
|
@end ifset
|
|
@ifset M680X0
|
|
@samp{|} on the 680x0;
|
|
@end ifset
|
|
@ifset A29K
|
|
@samp{;} for the AMD 29K family;
|
|
@end ifset
|
|
@ifset H8/300
|
|
@samp{;} for the H8/300 family;
|
|
@end ifset
|
|
@ifset H8/500
|
|
@samp{!} for the H8/500 family;
|
|
@end ifset
|
|
@ifset HPPA
|
|
@samp{;} for the HPPA;
|
|
@end ifset
|
|
@ifset SH
|
|
@samp{!} for the Hitachi SH;
|
|
@end ifset
|
|
@ifset Z8000
|
|
@samp{!} for the Z8000;
|
|
@end ifset
|
|
see @ref{Machine Dependencies}. @refill
|
|
@c FIXME What about i386, m88k, i860?
|
|
|
|
@ifset GENERIC
|
|
On some machines there are two different line comment characters. One
|
|
character only begins a comment if it is the first non-whitespace character on
|
|
a line, while the other always begins a comment.
|
|
@end ifset
|
|
|
|
@kindex #
|
|
@cindex lines starting with @code{#}
|
|
@cindex logical line numbers
|
|
To be compatible with past assemblers, lines that begin with @samp{#} have a
|
|
special interpretation. Following the @samp{#} should be an absolute
|
|
expression (@pxref{Expressions}): the logical line number of the @emph{next}
|
|
line. Then a string (@pxref{Strings,, Strings}) is allowed: if present it is a
|
|
new logical file name. The rest of the line, if any, should be whitespace.
|
|
|
|
If the first non-whitespace characters on the line are not numeric,
|
|
the line is ignored. (Just like a comment.)
|
|
|
|
@smallexample
|
|
# This is an ordinary comment.
|
|
# 42-6 "new_file_name" # New logical file name
|
|
# This is logical line # 36.
|
|
@end smallexample
|
|
This feature is deprecated, and may disappear from future versions
|
|
of @code{@value{AS}}.
|
|
|
|
@node Symbol Intro
|
|
@section Symbols
|
|
|
|
@cindex characters used in symbols
|
|
@ifclear SPECIAL-SYMS
|
|
A @dfn{symbol} is one or more characters chosen from the set of all
|
|
letters (both upper and lower case), digits and the three characters
|
|
@samp{_.$}.
|
|
@end ifclear
|
|
@ifset SPECIAL-SYMS
|
|
@ifclear GENERIC
|
|
@ifset H8
|
|
A @dfn{symbol} is one or more characters chosen from the set of all
|
|
letters (both upper and lower case), digits and the three characters
|
|
@samp{._$}. (Save that, on the H8/300 only, you may not use @samp{$} in
|
|
symbol names.)
|
|
@end ifset
|
|
@end ifclear
|
|
@end ifset
|
|
@ifset GENERIC
|
|
On most machines, you can also use @code{$} in symbol names; exceptions
|
|
are noted in @ref{Machine Dependencies}.
|
|
@end ifset
|
|
No symbol may begin with a digit. Case is significant.
|
|
There is no length limit: all characters are significant. Symbols are
|
|
delimited by characters not in that set, or by the beginning of a file
|
|
(since the source program must end with a newline, the end of a file is
|
|
not a possible symbol delimiter). @xref{Symbols}.
|
|
@cindex length of symbols
|
|
|
|
@node Statements
|
|
@section Statements
|
|
|
|
@cindex statements, structure of
|
|
@cindex line separator character
|
|
@cindex statement separator character
|
|
@ifclear GENERIC
|
|
@ifclear abnormal-separator
|
|
A @dfn{statement} ends at a newline character (@samp{\n}) or at a
|
|
semicolon (@samp{;}). The newline or semicolon is considered part of
|
|
the preceding statement. Newlines and semicolons within character
|
|
constants are an exception: they do not end statements.
|
|
@end ifclear
|
|
@ifset abnormal-separator
|
|
@ifset A29K
|
|
A @dfn{statement} ends at a newline character (@samp{\n}) or an ``at''
|
|
sign (@samp{@@}). The newline or at sign is considered part of the
|
|
preceding statement. Newlines and at signs within character constants
|
|
are an exception: they do not end statements.
|
|
@end ifset
|
|
@ifset HPPA
|
|
A @dfn{statement} ends at a newline character (@samp{\n}) or an exclamation
|
|
point (@samp{!}). The newline or exclamation point is considered part of the
|
|
preceding statement. Newlines and exclamation points within character
|
|
constants are an exception: they do not end statements.
|
|
@end ifset
|
|
@ifset H8
|
|
A @dfn{statement} ends at a newline character (@samp{\n}); or (for the
|
|
H8/300) a dollar sign (@samp{$}); or (for the
|
|
Hitachi-SH or the
|
|
H8/500) a semicolon
|
|
(@samp{;}). The newline or separator character is considered part of
|
|
the preceding statement. Newlines and separators within character
|
|
constants are an exception: they do not end statements.
|
|
@end ifset
|
|
@end ifset
|
|
@end ifclear
|
|
@ifset GENERIC
|
|
A @dfn{statement} ends at a newline character (@samp{\n}) or line
|
|
separator character. (The line separator is usually @samp{;}, unless
|
|
this conflicts with the comment character; @pxref{Machine Dependencies}.) The
|
|
newline or separator character is considered part of the preceding
|
|
statement. Newlines and separators within character constants are an
|
|
exception: they do not end statements.
|
|
@end ifset
|
|
|
|
@cindex newline, required at file end
|
|
@cindex EOF, newline must precede
|
|
It is an error to end any statement with end-of-file: the last
|
|
character of any input file should be a newline.@refill
|
|
|
|
@cindex continuing statements
|
|
@cindex multi-line statements
|
|
@cindex statement on multiple lines
|
|
You may write a statement on more than one line if you put a
|
|
backslash (@kbd{\}) immediately in front of any newlines within the
|
|
statement. When @code{@value{AS}} reads a backslashed newline both
|
|
characters are ignored. You can even put backslashed newlines in
|
|
the middle of symbol names without changing the meaning of your
|
|
source program.
|
|
|
|
An empty statement is allowed, and may include whitespace. It is ignored.
|
|
|
|
@cindex instructions and directives
|
|
@cindex directives and instructions
|
|
@c "key symbol" is not used elsewhere in the document; seems pedantic to
|
|
@c @defn{} it in that case, as was done previously... pesch@cygnus.com,
|
|
@c 13feb91.
|
|
A statement begins with zero or more labels, optionally followed by a
|
|
key symbol which determines what kind of statement it is. The key
|
|
symbol determines the syntax of the rest of the statement. If the
|
|
symbol begins with a dot @samp{.} then the statement is an assembler
|
|
directive: typically valid for any computer. If the symbol begins with
|
|
a letter the statement is an assembly language @dfn{instruction}: it
|
|
assembles into a machine language instruction.
|
|
@ifset GENERIC
|
|
Different versions of @code{@value{AS}} for different computers
|
|
recognize different instructions. In fact, the same symbol may
|
|
represent a different instruction in a different computer's assembly
|
|
language.@refill
|
|
@end ifset
|
|
|
|
@cindex @code{:} (label)
|
|
@cindex label (@code{:})
|
|
A label is a symbol immediately followed by a colon (@code{:}).
|
|
Whitespace before a label or after a colon is permitted, but you may not
|
|
have whitespace between a label's symbol and its colon. @xref{Labels}.
|
|
|
|
@ifset HPPA
|
|
For HPPA targets, labels need not be immediately followed by a colon, but
|
|
the definition of a label must begin in column zero. This also implies that
|
|
only one label may be defined on each line.
|
|
@end ifset
|
|
|
|
@smallexample
|
|
label: .directive followed by something
|
|
another_label: # This is an empty statement.
|
|
instruction operand_1, operand_2, @dots{}
|
|
@end smallexample
|
|
|
|
@node Constants
|
|
@section Constants
|
|
|
|
@cindex constants
|
|
A constant is a number, written so that its value is known by
|
|
inspection, without knowing any context. Like this:
|
|
@smallexample
|
|
@group
|
|
.byte 74, 0112, 092, 0x4A, 0X4a, 'J, '\J # All the same value.
|
|
.ascii "Ring the bell\7" # A string constant.
|
|
.octa 0x123456789abcdef0123456789ABCDEF0 # A bignum.
|
|
.float 0f-314159265358979323846264338327\
|
|
95028841971.693993751E-40 # - pi, a flonum.
|
|
@end group
|
|
@end smallexample
|
|
|
|
@menu
|
|
* Characters:: Character Constants
|
|
* Numbers:: Number Constants
|
|
@end menu
|
|
|
|
@node Characters
|
|
@subsection Character Constants
|
|
|
|
@cindex character constants
|
|
@cindex constants, character
|
|
There are two kinds of character constants. A @dfn{character} stands
|
|
for one character in one byte and its value may be used in
|
|
numeric expressions. String constants (properly called string
|
|
@emph{literals}) are potentially many bytes and their values may not be
|
|
used in arithmetic expressions.
|
|
|
|
@menu
|
|
* Strings:: Strings
|
|
* Chars:: Characters
|
|
@end menu
|
|
|
|
@node Strings
|
|
@subsubsection Strings
|
|
|
|
@cindex string constants
|
|
@cindex constants, string
|
|
A @dfn{string} is written between double-quotes. It may contain
|
|
double-quotes or null characters. The way to get special characters
|
|
into a string is to @dfn{escape} these characters: precede them with
|
|
a backslash @samp{\} character. For example @samp{\\} represents
|
|
one backslash: the first @code{\} is an escape which tells
|
|
@code{@value{AS}} to interpret the second character literally as a backslash
|
|
(which prevents @code{@value{AS}} from recognizing the second @code{\} as an
|
|
escape character). The complete list of escapes follows.
|
|
|
|
@cindex escape codes, character
|
|
@cindex character escape codes
|
|
@table @kbd
|
|
@c @item \a
|
|
@c Mnemonic for ACKnowledge; for ASCII this is octal code 007.
|
|
@c
|
|
@item \b
|
|
@cindex @code{\b} (backspace character)
|
|
@cindex backspace (@code{\b})
|
|
Mnemonic for backspace; for ASCII this is octal code 010.
|
|
|
|
@c @item \e
|
|
@c Mnemonic for EOText; for ASCII this is octal code 004.
|
|
@c
|
|
@item \f
|
|
@cindex @code{\f} (formfeed character)
|
|
@cindex formfeed (@code{\f})
|
|
Mnemonic for FormFeed; for ASCII this is octal code 014.
|
|
|
|
@item \n
|
|
@cindex @code{\n} (newline character)
|
|
@cindex newline (@code{\n})
|
|
Mnemonic for newline; for ASCII this is octal code 012.
|
|
|
|
@c @item \p
|
|
@c Mnemonic for prefix; for ASCII this is octal code 033, usually known as @code{escape}.
|
|
@c
|
|
@item \r
|
|
@cindex @code{\r} (carriage return character)
|
|
@cindex carriage return (@code{\r})
|
|
Mnemonic for carriage-Return; for ASCII this is octal code 015.
|
|
|
|
@c @item \s
|
|
@c Mnemonic for space; for ASCII this is octal code 040. Included for compliance with
|
|
@c other assemblers.
|
|
@c
|
|
@item \t
|
|
@cindex @code{\t} (tab)
|
|
@cindex tab (@code{\t})
|
|
Mnemonic for horizontal Tab; for ASCII this is octal code 011.
|
|
|
|
@c @item \v
|
|
@c Mnemonic for Vertical tab; for ASCII this is octal code 013.
|
|
@c @item \x @var{digit} @var{digit} @var{digit}
|
|
@c A hexadecimal character code. The numeric code is 3 hexadecimal digits.
|
|
@c
|
|
@item \ @var{digit} @var{digit} @var{digit}
|
|
@cindex @code{\@var{ddd}} (octal character code)
|
|
@cindex octal character code (@code{\@var{ddd}})
|
|
An octal character code. The numeric code is 3 octal digits.
|
|
For compatibility with other Unix systems, 8 and 9 are accepted as digits:
|
|
for example, @code{\008} has the value 010, and @code{\009} the value 011.
|
|
|
|
@ifset HPPA
|
|
@item \@code{x} @var{hex-digit} @var{hex-digit}
|
|
@cindex @code{\@var{xdd}} (hex character code)
|
|
@cindex hex character code (@code{\@var{xdd}})
|
|
A hex character code. The numeric code is 2 hexadecimal digits. Either
|
|
upper or lower case @code{x} works.
|
|
@end ifset
|
|
|
|
@item \\
|
|
@cindex @code{\\} (@samp{\} character)
|
|
@cindex backslash (@code{\\})
|
|
Represents one @samp{\} character.
|
|
|
|
@c @item \'
|
|
@c Represents one @samp{'} (accent acute) character.
|
|
@c This is needed in single character literals
|
|
@c (@xref{Characters,,Character Constants}.) to represent
|
|
@c a @samp{'}.
|
|
@c
|
|
@item \"
|
|
@cindex @code{\"} (doublequote character)
|
|
@cindex doublequote (@code{\"})
|
|
Represents one @samp{"} character. Needed in strings to represent
|
|
this character, because an unescaped @samp{"} would end the string.
|
|
|
|
@item \ @var{anything-else}
|
|
Any other character when escaped by @kbd{\} gives a warning, but
|
|
assembles as if the @samp{\} was not present. The idea is that if
|
|
you used an escape sequence you clearly didn't want the literal
|
|
interpretation of the following character. However @code{@value{AS}} has no
|
|
other interpretation, so @code{@value{AS}} knows it is giving you the wrong
|
|
code and warns you of the fact.
|
|
@end table
|
|
|
|
Which characters are escapable, and what those escapes represent,
|
|
varies widely among assemblers. The current set is what we think
|
|
the BSD 4.2 assembler recognizes, and is a subset of what most C
|
|
compilers recognize. If you are in doubt, do not use an escape
|
|
sequence.
|
|
|
|
@node Chars
|
|
@subsubsection Characters
|
|
|
|
@cindex single character constant
|
|
@cindex character, single
|
|
@cindex constant, single character
|
|
A single character may be written as a single quote immediately
|
|
followed by that character. The same escapes apply to characters as
|
|
to strings. So if you want to write the character backslash, you
|
|
must write @kbd{'\\} where the first @code{\} escapes the second
|
|
@code{\}. As you can see, the quote is an acute accent, not a
|
|
grave accent. A newline
|
|
@ifclear GENERIC
|
|
@ifclear abnormal-separator
|
|
(or semicolon @samp{;})
|
|
@end ifclear
|
|
@ifset abnormal-separator
|
|
@ifset A29K
|
|
(or at sign @samp{@@})
|
|
@end ifset
|
|
@ifset H8
|
|
(or dollar sign @samp{$}, for the H8/300; or semicolon @samp{;} for the
|
|
Hitachi SH or
|
|
H8/500)
|
|
@end ifset
|
|
@end ifset
|
|
@end ifclear
|
|
immediately following an acute accent is taken as a literal character
|
|
and does not count as the end of a statement. The value of a character
|
|
constant in a numeric expression is the machine's byte-wide code for
|
|
that character. @code{@value{AS}} assumes your character code is ASCII:
|
|
@kbd{'A} means 65, @kbd{'B} means 66, and so on. @refill
|
|
|
|
@node Numbers
|
|
@subsection Number Constants
|
|
|
|
@cindex constants, number
|
|
@cindex number constants
|
|
@code{@value{AS}} distinguishes three kinds of numbers according to how they
|
|
are stored in the target machine. @emph{Integers} are numbers that
|
|
would fit into an @code{int} in the C language. @emph{Bignums} are
|
|
integers, but they are stored in more than 32 bits. @emph{Flonums}
|
|
are floating point numbers, described below.
|
|
|
|
@menu
|
|
* Integers:: Integers
|
|
* Bignums:: Bignums
|
|
* Flonums:: Flonums
|
|
@ifclear GENERIC
|
|
@ifset I960
|
|
* Bit Fields:: Bit Fields
|
|
@end ifset
|
|
@end ifclear
|
|
@end menu
|
|
|
|
@node Integers
|
|
@subsubsection Integers
|
|
@cindex integers
|
|
@cindex constants, integer
|
|
|
|
@cindex binary integers
|
|
@cindex integers, binary
|
|
A binary integer is @samp{0b} or @samp{0B} followed by zero or more of
|
|
the binary digits @samp{01}.
|
|
|
|
@cindex octal integers
|
|
@cindex integers, octal
|
|
An octal integer is @samp{0} followed by zero or more of the octal
|
|
digits (@samp{01234567}).
|
|
|
|
@cindex decimal integers
|
|
@cindex integers, decimal
|
|
A decimal integer starts with a non-zero digit followed by zero or
|
|
more digits (@samp{0123456789}).
|
|
|
|
@cindex hexadecimal integers
|
|
@cindex integers, hexadecimal
|
|
A hexadecimal integer is @samp{0x} or @samp{0X} followed by one or
|
|
more hexadecimal digits chosen from @samp{0123456789abcdefABCDEF}.
|
|
|
|
Integers have the usual values. To denote a negative integer, use
|
|
the prefix operator @samp{-} discussed under expressions
|
|
(@pxref{Prefix Ops,,Prefix Operators}).
|
|
|
|
@node Bignums
|
|
@subsubsection Bignums
|
|
|
|
@cindex bignums
|
|
@cindex constants, bignum
|
|
A @dfn{bignum} has the same syntax and semantics as an integer
|
|
except that the number (or its negative) takes more than 32 bits to
|
|
represent in binary. The distinction is made because in some places
|
|
integers are permitted while bignums are not.
|
|
|
|
@node Flonums
|
|
@subsubsection Flonums
|
|
@cindex flonums
|
|
@cindex floating point numbers
|
|
@cindex constants, floating point
|
|
|
|
@cindex precision, floating point
|
|
A @dfn{flonum} represents a floating point number. The translation is
|
|
indirect: a decimal floating point number from the text is converted by
|
|
@code{@value{AS}} to a generic binary floating point number of more than
|
|
sufficient precision. This generic floating point number is converted
|
|
to a particular computer's floating point format (or formats) by a
|
|
portion of @code{@value{AS}} specialized to that computer.
|
|
|
|
A flonum is written by writing (in order)
|
|
@itemize @bullet
|
|
@item
|
|
The digit @samp{0}.
|
|
@ifset HPPA
|
|
(@samp{0} is optional on the HPPA.)
|
|
@end ifset
|
|
|
|
@item
|
|
A letter, to tell @code{@value{AS}} the rest of the number is a flonum.
|
|
@ifset GENERIC
|
|
@kbd{e} is recommended. Case is not important.
|
|
@ignore
|
|
@c FIXME: verify if flonum syntax really this vague for most cases
|
|
(Any otherwise illegal letter works here, but that might be changed. Vax BSD
|
|
4.2 assembler seems to allow any of @samp{defghDEFGH}.)
|
|
@end ignore
|
|
|
|
On the H8/300, H8/500,
|
|
Hitachi SH,
|
|
and AMD 29K architectures, the letter must be
|
|
one of the letters @samp{DFPRSX} (in upper or lower case).
|
|
|
|
On the Intel 960 architecture, the letter must be
|
|
one of the letters @samp{DFT} (in upper or lower case).
|
|
|
|
On the HPPA architecture, the letter must be @samp{E} (upper case only).
|
|
@end ifset
|
|
@ifclear GENERIC
|
|
@ifset A29K
|
|
One of the letters @samp{DFPRSX} (in upper or lower case).
|
|
@end ifset
|
|
@ifset H8
|
|
One of the letters @samp{DFPRSX} (in upper or lower case).
|
|
@end ifset
|
|
@ifset I960
|
|
One of the letters @samp{DFT} (in upper or lower case).
|
|
@end ifset
|
|
@ifset HPPA
|
|
The letter @samp{E} (upper case only).
|
|
@end ifset
|
|
@end ifclear
|
|
|
|
@item
|
|
An optional sign: either @samp{+} or @samp{-}.
|
|
|
|
@item
|
|
An optional @dfn{integer part}: zero or more decimal digits.
|
|
|
|
@item
|
|
An optional @dfn{fractional part}: @samp{.} followed by zero
|
|
or more decimal digits.
|
|
|
|
@item
|
|
An optional exponent, consisting of:
|
|
|
|
@itemize @bullet
|
|
@item
|
|
An @samp{E} or @samp{e}.
|
|
@c I can't find a config where "EXP_CHARS" is other than 'eE', but in
|
|
@c principle this can perfectly well be different on different targets.
|
|
@item
|
|
Optional sign: either @samp{+} or @samp{-}.
|
|
@item
|
|
One or more decimal digits.
|
|
@end itemize
|
|
|
|
@end itemize
|
|
|
|
At least one of the integer part or the fractional part must be
|
|
present. The floating point number has the usual base-10 value.
|
|
|
|
@code{@value{AS}} does all processing using integers. Flonums are computed
|
|
independently of any floating point hardware in the computer running
|
|
@code{@value{AS}}.
|
|
|
|
@ifclear GENERIC
|
|
@ifset I960
|
|
@c Bit fields are written as a general facility but are also controlled
|
|
@c by a conditional-compilation flag---which is as of now (21mar91)
|
|
@c turned on only by the i960 config of GAS.
|
|
@node Bit Fields
|
|
@subsubsection Bit Fields
|
|
|
|
@cindex bit fields
|
|
@cindex constants, bit field
|
|
You can also define numeric constants as @dfn{bit fields}.
|
|
specify two numbers separated by a colon---
|
|
@example
|
|
@var{mask}:@var{value}
|
|
@end example
|
|
@noindent
|
|
@code{@value{AS}} applies a bitwise @sc{and} between @var{mask} and
|
|
@var{value}.
|
|
|
|
The resulting number is then packed
|
|
@ifset GENERIC
|
|
@c this conditional paren in case bit fields turned on elsewhere than 960
|
|
(in host-dependent byte order)
|
|
@end ifset
|
|
into a field whose width depends on which assembler directive has the
|
|
bit-field as its argument. Overflow (a result from the bitwise and
|
|
requiring more binary digits to represent) is not an error; instead,
|
|
more constants are generated, of the specified width, beginning with the
|
|
least significant digits.@refill
|
|
|
|
The directives @code{.byte}, @code{.hword}, @code{.int}, @code{.long},
|
|
@code{.short}, and @code{.word} accept bit-field arguments.
|
|
@end ifset
|
|
@end ifclear
|
|
|
|
@node Sections
|
|
@chapter Sections and Relocation
|
|
@cindex sections
|
|
@cindex relocation
|
|
|
|
@menu
|
|
* Secs Background:: Background
|
|
* Ld Sections:: @value{LD} Sections
|
|
* As Sections:: @value{AS} Internal Sections
|
|
* Sub-Sections:: Sub-Sections
|
|
* bss:: bss Section
|
|
@end menu
|
|
|
|
@node Secs Background
|
|
@section Background
|
|
|
|
Roughly, a section is a range of addresses, with no gaps; all data
|
|
``in'' those addresses is treated the same for some particular purpose.
|
|
For example there may be a ``read only'' section.
|
|
|
|
@cindex linker, and assembler
|
|
@cindex assembler, and linker
|
|
The linker @code{@value{LD}} reads many object files (partial programs) and
|
|
combines their contents to form a runnable program. When @code{@value{AS}}
|
|
emits an object file, the partial program is assumed to start at address 0.
|
|
@code{@value{LD}} assigns the final addresses for the partial program, so that
|
|
different partial programs do not overlap. This is actually an
|
|
oversimplification, but it suffices to explain how @code{@value{AS}} uses
|
|
sections.
|
|
|
|
@code{@value{LD}} moves blocks of bytes of your program to their run-time
|
|
addresses. These blocks slide to their run-time addresses as rigid
|
|
units; their length does not change and neither does the order of bytes
|
|
within them. Such a rigid unit is called a @emph{section}. Assigning
|
|
run-time addresses to sections is called @dfn{relocation}. It includes
|
|
the task of adjusting mentions of object-file addresses so they refer to
|
|
the proper run-time addresses.
|
|
@ifset H8
|
|
For the H8/300 and H8/500,
|
|
and for the Hitachi SH,
|
|
@code{@value{AS}} pads sections if needed to
|
|
ensure they end on a word (sixteen bit) boundary.
|
|
@end ifset
|
|
|
|
@cindex standard @code{@value{AS}} sections
|
|
An object file written by @code{@value{AS}} has at least three sections, any
|
|
of which may be empty. These are named @dfn{text}, @dfn{data} and
|
|
@dfn{bss} sections.
|
|
|
|
@ifset COFF
|
|
@ifset GENERIC
|
|
When it generates COFF output,
|
|
@end ifset
|
|
@code{@value{AS}} can also generate whatever other named sections you specify
|
|
using the @samp{.section} directive (@pxref{Section,,@code{.section}}).
|
|
If you do not use any directives that place output in the @samp{.text}
|
|
or @samp{.data} sections, these sections still exist, but are empty.
|
|
@end ifset
|
|
|
|
@ifset HPPA
|
|
@ifset GENERIC
|
|
When @code{@value{AS}} generates SOM or ELF output for the HPPA,
|
|
@end ifset
|
|
@code{@value{AS}} can also generate whatever other named sections you
|
|
specify using the @samp{.space} and @samp{.subspace} directives. See
|
|
@cite{HP9000 Series 800 Assembly Language Reference Manual}
|
|
(HP 92432-90001) for details on the @samp{.space} and @samp{.subspace}
|
|
assembler directives.
|
|
|
|
@ifset SOM
|
|
Additionally, @code{@value{AS}} uses different names for the standard
|
|
text, data, and bss sections when generating SOM output. Program text
|
|
is placed into the @samp{$CODE$} section, data into @samp{$DATA$}, and
|
|
BSS into @samp{$BSS$}.
|
|
@end ifset
|
|
@end ifset
|
|
|
|
Within the object file, the text section starts at address @code{0}, the
|
|
data section follows, and the bss section follows the data section.
|
|
|
|
@ifset HPPA
|
|
When generating either SOM or ELF output files on the HPPA, the text
|
|
section starts at address @code{0}, the data section at address
|
|
@code{0x4000000}, and the bss section follows the data section.
|
|
@end ifset
|
|
|
|
To let @code{@value{LD}} know which data changes when the sections are
|
|
relocated, and how to change that data, @code{@value{AS}} also writes to the
|
|
object file details of the relocation needed. To perform relocation
|
|
@code{@value{LD}} must know, each time an address in the object
|
|
file is mentioned:
|
|
@itemize @bullet
|
|
@item
|
|
Where in the object file is the beginning of this reference to
|
|
an address?
|
|
@item
|
|
How long (in bytes) is this reference?
|
|
@item
|
|
Which section does the address refer to? What is the numeric value of
|
|
@display
|
|
(@var{address}) @minus{} (@var{start-address of section})?
|
|
@end display
|
|
@item
|
|
Is the reference to an address ``Program-Counter relative''?
|
|
@end itemize
|
|
|
|
@cindex addresses, format of
|
|
@cindex section-relative addressing
|
|
In fact, every address @code{@value{AS}} ever uses is expressed as
|
|
@display
|
|
(@var{section}) + (@var{offset into section})
|
|
@end display
|
|
@noindent
|
|
Further, most expressions @code{@value{AS}} computes have this section-relative
|
|
nature.
|
|
@ifset SOM
|
|
(For some object formats, such as SOM for the HPPA, some expressions are
|
|
symbol-relative instead.)
|
|
@end ifset
|
|
|
|
In this manual we use the notation @{@var{secname} @var{N}@} to mean ``offset
|
|
@var{N} into section @var{secname}.''
|
|
|
|
Apart from text, data and bss sections you need to know about the
|
|
@dfn{absolute} section. When @code{@value{LD}} mixes partial programs,
|
|
addresses in the absolute section remain unchanged. For example, address
|
|
@code{@{absolute 0@}} is ``relocated'' to run-time address 0 by
|
|
@code{@value{LD}}. Although the linker never arranges two partial programs'
|
|
data sections with overlapping addresses after linking, @emph{by definition}
|
|
their absolute sections must overlap. Address @code{@{absolute@ 239@}} in one
|
|
part of a program is always the same address when the program is running as
|
|
address @code{@{absolute@ 239@}} in any other part of the program.
|
|
|
|
The idea of sections is extended to the @dfn{undefined} section. Any
|
|
address whose section is unknown at assembly time is by definition
|
|
rendered @{undefined @var{U}@}---where @var{U} is filled in later.
|
|
Since numbers are always defined, the only way to generate an undefined
|
|
address is to mention an undefined symbol. A reference to a named
|
|
common block would be such a symbol: its value is unknown at assembly
|
|
time so it has section @emph{undefined}.
|
|
|
|
By analogy the word @emph{section} is used to describe groups of sections in
|
|
the linked program. @code{@value{LD}} puts all partial programs' text
|
|
sections in contiguous addresses in the linked program. It is
|
|
customary to refer to the @emph{text section} of a program, meaning all
|
|
the addresses of all partial programs' text sections. Likewise for
|
|
data and bss sections.
|
|
|
|
Some sections are manipulated by @code{@value{LD}}; others are invented for
|
|
use of @code{@value{AS}} and have no meaning except during assembly.
|
|
|
|
@node Ld Sections
|
|
@section @value{LD} Sections
|
|
@code{@value{LD}} deals with just four kinds of sections, summarized below.
|
|
|
|
@table @strong
|
|
|
|
@ifset COFF
|
|
@cindex named sections
|
|
@cindex sections, named
|
|
@item named sections
|
|
@end ifset
|
|
@ifset aout-bout
|
|
@cindex text section
|
|
@cindex data section
|
|
@itemx text section
|
|
@itemx data section
|
|
@end ifset
|
|
These sections hold your program. @code{@value{AS}} and @code{@value{LD}} treat them as
|
|
separate but equal sections. Anything you can say of one section is
|
|
true another.
|
|
@ifset aout-bout
|
|
When the program is running, however, it is
|
|
customary for the text section to be unalterable. The
|
|
text section is often shared among processes: it contains
|
|
instructions, constants and the like. The data section of a running
|
|
program is usually alterable: for example, C variables would be stored
|
|
in the data section.
|
|
@end ifset
|
|
|
|
@cindex bss section
|
|
@item bss section
|
|
This section contains zeroed bytes when your program begins running. It
|
|
is used to hold unitialized variables or common storage. The length of
|
|
each partial program's bss section is important, but because it starts
|
|
out containing zeroed bytes there is no need to store explicit zero
|
|
bytes in the object file. The bss section was invented to eliminate
|
|
those explicit zeros from object files.
|
|
|
|
@cindex absolute section
|
|
@item absolute section
|
|
Address 0 of this section is always ``relocated'' to runtime address 0.
|
|
This is useful if you want to refer to an address that @code{@value{LD}} must
|
|
not change when relocating. In this sense we speak of absolute
|
|
addresses being ``unrelocatable'': they do not change during relocation.
|
|
|
|
@cindex undefined section
|
|
@item undefined section
|
|
This ``section'' is a catch-all for address references to objects not in
|
|
the preceding sections.
|
|
@c FIXME: ref to some other doc on obj-file formats could go here.
|
|
@end table
|
|
|
|
@cindex relocation example
|
|
An idealized example of three relocatable sections follows.
|
|
@ifset COFF
|
|
The example uses the traditional section names @samp{.text} and @samp{.data}.
|
|
@end ifset
|
|
Memory addresses are on the horizontal axis.
|
|
|
|
@c TEXI2ROFF-KILL
|
|
@ifinfo
|
|
@c END TEXI2ROFF-KILL
|
|
@smallexample
|
|
+-----+----+--+
|
|
partial program # 1: |ttttt|dddd|00|
|
|
+-----+----+--+
|
|
|
|
text data bss
|
|
seg. seg. seg.
|
|
|
|
+---+---+---+
|
|
partial program # 2: |TTT|DDD|000|
|
|
+---+---+---+
|
|
|
|
+--+---+-----+--+----+---+-----+~~
|
|
linked program: | |TTT|ttttt| |dddd|DDD|00000|
|
|
+--+---+-----+--+----+---+-----+~~
|
|
|
|
addresses: 0 @dots{}
|
|
@end smallexample
|
|
@c TEXI2ROFF-KILL
|
|
@end ifinfo
|
|
@need 5000
|
|
@tex
|
|
|
|
\line{\it Partial program \#1: \hfil}
|
|
\line{\ibox{2.5cm}{\tt text}\ibox{2cm}{\tt data}\ibox{1cm}{\tt bss}\hfil}
|
|
\line{\boxit{2.5cm}{\tt ttttt}\boxit{2cm}{\tt dddd}\boxit{1cm}{\tt 00}\hfil}
|
|
|
|
\line{\it Partial program \#2: \hfil}
|
|
\line{\ibox{1cm}{\tt text}\ibox{1.5cm}{\tt data}\ibox{1cm}{\tt bss}\hfil}
|
|
\line{\boxit{1cm}{\tt TTT}\boxit{1.5cm}{\tt DDDD}\boxit{1cm}{\tt 000}\hfil}
|
|
|
|
\line{\it linked program: \hfil}
|
|
\line{\ibox{.5cm}{}\ibox{1cm}{\tt text}\ibox{2.5cm}{}\ibox{.75cm}{}\ibox{2cm}{\tt data}\ibox{1.5cm}{}\ibox{2cm}{\tt bss}\hfil}
|
|
\line{\boxit{.5cm}{}\boxit{1cm}{\tt TTT}\boxit{2.5cm}{\tt
|
|
ttttt}\boxit{.75cm}{}\boxit{2cm}{\tt dddd}\boxit{1.5cm}{\tt
|
|
DDDD}\boxit{2cm}{\tt 00000}\ \dots\hfil}
|
|
|
|
\line{\it addresses: \hfil}
|
|
\line{0\dots\hfil}
|
|
|
|
@end tex
|
|
@c END TEXI2ROFF-KILL
|
|
|
|
@node As Sections
|
|
@section @value{AS} Internal Sections
|
|
|
|
@cindex internal @code{@value{AS}} sections
|
|
@cindex sections in messages, internal
|
|
These sections are meant only for the internal use of @code{@value{AS}}. They
|
|
have no meaning at run-time. You do not really need to know about these
|
|
sections for most purposes; but they can be mentioned in @code{@value{AS}}
|
|
warning messages, so it might be helpful to have an idea of their
|
|
meanings to @code{@value{AS}}. These sections are used to permit the
|
|
value of every expression in your assembly language program to be a
|
|
section-relative address.
|
|
|
|
@table @b
|
|
@item ASSEMBLER-INTERNAL-LOGIC-ERROR!
|
|
@cindex assembler internal logic error
|
|
An internal assembler logic error has been found. This means there is a
|
|
bug in the assembler.
|
|
|
|
@item expr section
|
|
@cindex expr (internal section)
|
|
The assembler stores complex expression internally as combinations of
|
|
symbols. When it needs to represent an expression as a symbol, it puts
|
|
it in the expr section.
|
|
@c FIXME item debug
|
|
@c FIXME item transfer[t] vector preload
|
|
@c FIXME item transfer[t] vector postload
|
|
@c FIXME item register
|
|
@end table
|
|
|
|
@node Sub-Sections
|
|
@section Sub-Sections
|
|
|
|
@cindex numbered subsections
|
|
@cindex grouping data
|
|
@ifset aout-bout
|
|
Assembled bytes
|
|
@ifset COFF
|
|
conventionally
|
|
@end ifset
|
|
fall into two sections: text and data.
|
|
@end ifset
|
|
You may have separate groups of
|
|
@ifset GENERIC
|
|
data in named sections
|
|
@end ifset
|
|
@ifclear GENERIC
|
|
@ifclear aout-bout
|
|
data in named sections
|
|
@end ifclear
|
|
@ifset aout-bout
|
|
text or data
|
|
@end ifset
|
|
@end ifclear
|
|
that you want to end up near to each other in the object file, even though they
|
|
are not contiguous in the assembler source. @code{@value{AS}} allows you to
|
|
use @dfn{subsections} for this purpose. Within each section, there can be
|
|
numbered subsections with values from 0 to 8192. Objects assembled into the
|
|
same subsection go into the object file together with other objects in the same
|
|
subsection. For example, a compiler might want to store constants in the text
|
|
section, but might not want to have them interspersed with the program being
|
|
assembled. In this case, the compiler could issue a @samp{.text 0} before each
|
|
section of code being output, and a @samp{.text 1} before each group of
|
|
constants being output.
|
|
|
|
Subsections are optional. If you do not use subsections, everything
|
|
goes in subsection number zero.
|
|
|
|
@ifset GENERIC
|
|
Each subsection is zero-padded up to a multiple of four bytes.
|
|
(Subsections may be padded a different amount on different flavors
|
|
of @code{@value{AS}}.)
|
|
@end ifset
|
|
@ifclear GENERIC
|
|
@ifset H8
|
|
On the H8/300 and H8/500 platforms, each subsection is zero-padded to a word
|
|
boundary (two bytes).
|
|
The same is true on the Hitachi SH.
|
|
@end ifset
|
|
@ifset I960
|
|
@c FIXME section padding (alignment)?
|
|
@c Rich Pixley says padding here depends on target obj code format; that
|
|
@c doesn't seem particularly useful to say without further elaboration,
|
|
@c so for now I say nothing about it. If this is a generic BFD issue,
|
|
@c these paragraphs might need to vanish from this manual, and be
|
|
@c discussed in BFD chapter of binutils (or some such).
|
|
@end ifset
|
|
@ifset A29K
|
|
On the AMD 29K family, no particular padding is added to section or
|
|
subsection sizes; @value{AS} forces no alignment on this platform.
|
|
@end ifset
|
|
@end ifclear
|
|
|
|
Subsections appear in your object file in numeric order, lowest numbered
|
|
to highest. (All this to be compatible with other people's assemblers.)
|
|
The object file contains no representation of subsections; @code{@value{LD}} and
|
|
other programs that manipulate object files see no trace of them.
|
|
They just see all your text subsections as a text section, and all your
|
|
data subsections as a data section.
|
|
|
|
To specify which subsection you want subsequent statements assembled
|
|
into, use a numeric argument to specify it, in a @samp{.text
|
|
@var{expression}} or a @samp{.data @var{expression}} statement.
|
|
@ifset COFF
|
|
@ifset GENERIC
|
|
When generating COFF output, you
|
|
@end ifset
|
|
@ifclear GENERIC
|
|
You
|
|
@end ifclear
|
|
can also use an extra subsection
|
|
argument with arbitrary named sections: @samp{.section @var{name},
|
|
@var{expression}}.
|
|
@end ifset
|
|
@var{Expression} should be an absolute expression.
|
|
(@xref{Expressions}.) If you just say @samp{.text} then @samp{.text 0}
|
|
is assumed. Likewise @samp{.data} means @samp{.data 0}. Assembly
|
|
begins in @code{text 0}. For instance:
|
|
@smallexample
|
|
.text 0 # The default subsection is text 0 anyway.
|
|
.ascii "This lives in the first text subsection. *"
|
|
.text 1
|
|
.ascii "But this lives in the second text subsection."
|
|
.data 0
|
|
.ascii "This lives in the data section,"
|
|
.ascii "in the first data subsection."
|
|
.text 0
|
|
.ascii "This lives in the first text section,"
|
|
.ascii "immediately following the asterisk (*)."
|
|
@end smallexample
|
|
|
|
Each section has a @dfn{location counter} incremented by one for every byte
|
|
assembled into that section. Because subsections are merely a convenience
|
|
restricted to @code{@value{AS}} there is no concept of a subsection location
|
|
counter. There is no way to directly manipulate a location counter---but the
|
|
@code{.align} directive changes it, and any label definition captures its
|
|
current value. The location counter of the section where statements are being
|
|
assembled is said to be the @dfn{active} location counter.
|
|
|
|
@node bss
|
|
@section bss Section
|
|
|
|
@cindex bss section
|
|
@cindex common variable storage
|
|
The bss section is used for local common variable storage.
|
|
You may allocate address space in the bss section, but you may
|
|
not dictate data to load into it before your program executes. When
|
|
your program starts running, all the contents of the bss
|
|
section are zeroed bytes.
|
|
|
|
Addresses in the bss section are allocated with special directives; you
|
|
may not assemble anything directly into the bss section. Hence there
|
|
are no bss subsections. @xref{Comm,,@code{.comm}},
|
|
@pxref{Lcomm,,@code{.lcomm}}.
|
|
|
|
@node Symbols
|
|
@chapter Symbols
|
|
|
|
@cindex symbols
|
|
Symbols are a central concept: the programmer uses symbols to name
|
|
things, the linker uses symbols to link, and the debugger uses symbols
|
|
to debug.
|
|
|
|
@quotation
|
|
@cindex debuggers, and symbol order
|
|
@emph{Warning:} @code{@value{AS}} does not place symbols in the object file in
|
|
the same order they were declared. This may break some debuggers.
|
|
@end quotation
|
|
|
|
@menu
|
|
* Labels:: Labels
|
|
* Setting Symbols:: Giving Symbols Other Values
|
|
* Symbol Names:: Symbol Names
|
|
* Dot:: The Special Dot Symbol
|
|
* Symbol Attributes:: Symbol Attributes
|
|
@end menu
|
|
|
|
@node Labels
|
|
@section Labels
|
|
|
|
@cindex labels
|
|
A @dfn{label} is written as a symbol immediately followed by a colon
|
|
@samp{:}. The symbol then represents the current value of the
|
|
active location counter, and is, for example, a suitable instruction
|
|
operand. You are warned if you use the same symbol to represent two
|
|
different locations: the first definition overrides any other
|
|
definitions.
|
|
|
|
@ifset HPPA
|
|
On the HPPA, the usual form for a label need not be immediately followed by a
|
|
colon, but instead must start in column zero. Only one label may be defined on
|
|
a single line. To work around this, the HPPA version of @code{@value{AS}} also
|
|
provides a special directive @code{.label} for defining labels more flexibly.
|
|
@end ifset
|
|
|
|
@node Setting Symbols
|
|
@section Giving Symbols Other Values
|
|
|
|
@cindex assigning values to symbols
|
|
@cindex symbol values, assigning
|
|
A symbol can be given an arbitrary value by writing a symbol, followed
|
|
by an equals sign @samp{=}, followed by an expression
|
|
(@pxref{Expressions}). This is equivalent to using the @code{.set}
|
|
directive. @xref{Set,,@code{.set}}.
|
|
|
|
@node Symbol Names
|
|
@section Symbol Names
|
|
|
|
@cindex symbol names
|
|
@cindex names, symbol
|
|
@ifclear SPECIAL-SYMS
|
|
Symbol names begin with a letter or with one of @samp{._}. On most
|
|
machines, you can also use @code{$} in symbol names; exceptions are
|
|
noted in @ref{Machine Dependencies}. That character may be followed by any
|
|
string of digits, letters, dollar signs (unless otherwise noted in
|
|
@ref{Machine Dependencies}), and underscores.
|
|
@end ifclear
|
|
@ifset A29K
|
|
For the AMD 29K family, @samp{?} is also allowed in the
|
|
body of a symbol name, though not at its beginning.
|
|
@end ifset
|
|
|
|
@ifset SPECIAL-SYMS
|
|
@ifset H8
|
|
Symbol names begin with a letter or with one of @samp{._}. On the
|
|
Hitachi SH or the
|
|
H8/500, you can also use @code{$} in symbol names. That character may
|
|
be followed by any string of digits, letters, dollar signs (save on the
|
|
H8/300), and underscores.
|
|
@end ifset
|
|
@end ifset
|
|
|
|
Case of letters is significant: @code{foo} is a different symbol name
|
|
than @code{Foo}.
|
|
|
|
Each symbol has exactly one name. Each name in an assembly language program
|
|
refers to exactly one symbol. You may use that symbol name any number of times
|
|
in a program.
|
|
|
|
@subheading Local Symbol Names
|
|
|
|
@cindex local symbol names
|
|
@cindex symbol names, local
|
|
@cindex temporary symbol names
|
|
@cindex symbol names, temporary
|
|
Local symbols help compilers and programmers use names temporarily.
|
|
There are ten local symbol names, which are re-used throughout the
|
|
program. You may refer to them using the names @samp{0} @samp{1}
|
|
@dots{} @samp{9}. To define a local symbol, write a label of the form
|
|
@samp{@b{N}:} (where @b{N} represents any digit). To refer to the most
|
|
recent previous definition of that symbol write @samp{@b{N}b}, using the
|
|
same digit as when you defined the label. To refer to the next
|
|
definition of a local label, write @samp{@b{N}f}---where @b{N} gives you
|
|
a choice of 10 forward references. The @samp{b} stands for
|
|
``backwards'' and the @samp{f} stands for ``forwards''.
|
|
|
|
Local symbols are not emitted by the current @sc{gnu} C compiler.
|
|
|
|
There is no restriction on how you can use these labels, but
|
|
remember that at any point in the assembly you can refer to at most
|
|
10 prior local labels and to at most 10 forward local labels.
|
|
|
|
Local symbol names are only a notation device. They are immediately
|
|
transformed into more conventional symbol names before the assembler
|
|
uses them. The symbol names stored in the symbol table, appearing in
|
|
error messages and optionally emitted to the object file have these
|
|
parts:
|
|
|
|
@table @code
|
|
@item L
|
|
All local labels begin with @samp{L}. Normally both @code{@value{AS}} and
|
|
@code{@value{LD}} forget symbols that start with @samp{L}. These labels are
|
|
used for symbols you are never intended to see. If you use the
|
|
@samp{-L} option then @code{@value{AS}} retains these symbols in the
|
|
object file. If you also instruct @code{@value{LD}} to retain these symbols,
|
|
you may use them in debugging.
|
|
|
|
@item @var{digit}
|
|
If the label is written @samp{0:} then the digit is @samp{0}.
|
|
If the label is written @samp{1:} then the digit is @samp{1}.
|
|
And so on up through @samp{9:}.
|
|
|
|
@item @ctrl{A}
|
|
This unusual character is included so you do not accidentally invent
|
|
a symbol of the same name. The character has ASCII value
|
|
@samp{\001}.
|
|
|
|
@item @emph{ordinal number}
|
|
This is a serial number to keep the labels distinct. The first
|
|
@samp{0:} gets the number @samp{1}; The 15th @samp{0:} gets the
|
|
number @samp{15}; @emph{etc.}. Likewise for the other labels @samp{1:}
|
|
through @samp{9:}.
|
|
@end table
|
|
|
|
For instance, the first @code{1:} is named @code{L1@ctrl{A}1}, the 44th
|
|
@code{3:} is named @code{L3@ctrl{A}44}.
|
|
|
|
@node Dot
|
|
@section The Special Dot Symbol
|
|
|
|
@cindex dot (symbol)
|
|
@cindex @code{.} (symbol)
|
|
@cindex current address
|
|
@cindex location counter
|
|
The special symbol @samp{.} refers to the current address that
|
|
@code{@value{AS}} is assembling into. Thus, the expression @samp{melvin:
|
|
.long .} defines @code{melvin} to contain its own address.
|
|
Assigning a value to @code{.} is treated the same as a @code{.org}
|
|
directive. Thus, the expression @samp{.=.+4} is the same as saying
|
|
@ifclear no-space-dir
|
|
@samp{.space 4}.
|
|
@end ifclear
|
|
@ifset no-space-dir
|
|
@ifset A29K
|
|
@samp{.block 4}.
|
|
@end ifset
|
|
@end ifset
|
|
|
|
@node Symbol Attributes
|
|
@section Symbol Attributes
|
|
|
|
@cindex symbol attributes
|
|
@cindex attributes, symbol
|
|
Every symbol has, as well as its name, the attributes ``Value'' and
|
|
``Type''. Depending on output format, symbols can also have auxiliary
|
|
attributes.
|
|
@ifset INTERNALS
|
|
The detailed definitions are in @file{a.out.h}.
|
|
@end ifset
|
|
|
|
If you use a symbol without defining it, @code{@value{AS}} assumes zero for
|
|
all these attributes, and probably won't warn you. This makes the
|
|
symbol an externally defined symbol, which is generally what you
|
|
would want.
|
|
|
|
@menu
|
|
* Symbol Value:: Value
|
|
* Symbol Type:: Type
|
|
@ifset aout-bout
|
|
@ifset GENERIC
|
|
* a.out Symbols:: Symbol Attributes: @code{a.out}
|
|
@end ifset
|
|
@ifclear GENERIC
|
|
@ifclear BOUT
|
|
* a.out Symbols:: Symbol Attributes: @code{a.out}
|
|
@end ifclear
|
|
@ifset BOUT
|
|
* a.out Symbols:: Symbol Attributes: @code{a.out}, @code{b.out}
|
|
@end ifset
|
|
@end ifclear
|
|
@end ifset
|
|
@ifset COFF
|
|
* COFF Symbols:: Symbol Attributes for COFF
|
|
@end ifset
|
|
@ifset SOM
|
|
* SOM Symbols:: Symbol Attributes for SOM
|
|
@end ifset
|
|
@end menu
|
|
|
|
@node Symbol Value
|
|
@subsection Value
|
|
|
|
@cindex value of a symbol
|
|
@cindex symbol value
|
|
The value of a symbol is (usually) 32 bits. For a symbol which labels a
|
|
location in the text, data, bss or absolute sections the value is the
|
|
number of addresses from the start of that section to the label.
|
|
Naturally for text, data and bss sections the value of a symbol changes
|
|
as @code{@value{LD}} changes section base addresses during linking. Absolute
|
|
symbols' values do not change during linking: that is why they are
|
|
called absolute.
|
|
|
|
The value of an undefined symbol is treated in a special way. If it is
|
|
0 then the symbol is not defined in this assembler source file, and
|
|
@code{@value{LD}} tries to determine its value from other files linked into the
|
|
same program. You make this kind of symbol simply by mentioning a symbol
|
|
name without defining it. A non-zero value represents a @code{.comm}
|
|
common declaration. The value is how much common storage to reserve, in
|
|
bytes (addresses). The symbol refers to the first address of the
|
|
allocated storage.
|
|
|
|
@node Symbol Type
|
|
@subsection Type
|
|
|
|
@cindex type of a symbol
|
|
@cindex symbol type
|
|
The type attribute of a symbol contains relocation (section)
|
|
information, any flag settings indicating that a symbol is external, and
|
|
(optionally), other information for linkers and debuggers. The exact
|
|
format depends on the object-code output format in use.
|
|
|
|
@ifset aout-bout
|
|
@ifclear GENERIC
|
|
@ifset BOUT
|
|
@c The following avoids a "widow" subsection title. @group would be
|
|
@c better if it were available outside examples.
|
|
@need 1000
|
|
@node a.out Symbols
|
|
@subsection Symbol Attributes: @code{a.out}, @code{b.out}
|
|
|
|
@cindex @code{b.out} symbol attributes
|
|
@cindex symbol attributes, @code{b.out}
|
|
These symbol attributes appear only when @code{@value{AS}} is configured for
|
|
one of the Berkeley-descended object output formats---@code{a.out} or
|
|
@code{b.out}.
|
|
|
|
@end ifset
|
|
@ifclear BOUT
|
|
@node a.out Symbols
|
|
@subsection Symbol Attributes: @code{a.out}
|
|
|
|
@cindex @code{a.out} symbol attributes
|
|
@cindex symbol attributes, @code{a.out}
|
|
|
|
@end ifclear
|
|
@end ifclear
|
|
@ifset GENERIC
|
|
@node a.out Symbols
|
|
@subsection Symbol Attributes: @code{a.out}
|
|
|
|
@cindex @code{a.out} symbol attributes
|
|
@cindex symbol attributes, @code{a.out}
|
|
|
|
@end ifset
|
|
@menu
|
|
* Symbol Desc:: Descriptor
|
|
* Symbol Other:: Other
|
|
@end menu
|
|
|
|
@node Symbol Desc
|
|
@subsubsection Descriptor
|
|
|
|
@cindex descriptor, of @code{a.out} symbol
|
|
This is an arbitrary 16-bit value. You may establish a symbol's
|
|
descriptor value by using a @code{.desc} statement
|
|
(@pxref{Desc,,@code{.desc}}). A descriptor value means nothing to
|
|
@code{@value{AS}}.
|
|
|
|
@node Symbol Other
|
|
@subsubsection Other
|
|
|
|
@cindex other attribute, of @code{a.out} symbol
|
|
This is an arbitrary 8-bit value. It means nothing to @code{@value{AS}}.
|
|
@end ifset
|
|
|
|
@ifset COFF
|
|
@node COFF Symbols
|
|
@subsection Symbol Attributes for COFF
|
|
|
|
@cindex COFF symbol attributes
|
|
@cindex symbol attributes, COFF
|
|
|
|
The COFF format supports a multitude of auxiliary symbol attributes;
|
|
like the primary symbol attributes, they are set between @code{.def} and
|
|
@code{.endef} directives.
|
|
|
|
@subsubsection Primary Attributes
|
|
|
|
@cindex primary attributes, COFF symbols
|
|
The symbol name is set with @code{.def}; the value and type,
|
|
respectively, with @code{.val} and @code{.type}.
|
|
|
|
@subsubsection Auxiliary Attributes
|
|
|
|
@cindex auxiliary attributes, COFF symbols
|
|
The @code{@value{AS}} directives @code{.dim}, @code{.line}, @code{.scl},
|
|
@code{.size}, and @code{.tag} can generate auxiliary symbol table
|
|
information for COFF.
|
|
@end ifset
|
|
|
|
@ifset SOM
|
|
@node SOM Symbols
|
|
@subsection Symbol Attributes for SOM
|
|
|
|
@cindex SOM symbol attributes
|
|
@cindex symbol attributes, SOM
|
|
|
|
The SOM format for the HPPA supports a multitude of symbol attributes set with
|
|
the @code{.EXPORT} and @code{.IMPORT} directives.
|
|
|
|
The attributes are described in @cite{HP9000 Series 800 Assembly
|
|
Language Reference Manual} (HP 92432-90001) under the @code{IMPORT} and
|
|
@code{EXPORT} assembler directive documentation.
|
|
@end ifset
|
|
|
|
@node Expressions
|
|
@chapter Expressions
|
|
|
|
@cindex expressions
|
|
@cindex addresses
|
|
@cindex numeric values
|
|
An @dfn{expression} specifies an address or numeric value.
|
|
Whitespace may precede and/or follow an expression.
|
|
|
|
The result of an expression must be an absolute number, or else an offset into
|
|
a particular section. If an expression is not absolute, and there is not
|
|
enough information when @code{@value{AS}} sees the expression to know its
|
|
section, a second pass over the source program might be necessary to interpret
|
|
the expression---but the second pass is currently not implemented.
|
|
@code{@value{AS}} aborts with an error message in this situation.
|
|
|
|
@menu
|
|
* Empty Exprs:: Empty Expressions
|
|
* Integer Exprs:: Integer Expressions
|
|
@end menu
|
|
|
|
@node Empty Exprs
|
|
@section Empty Expressions
|
|
|
|
@cindex empty expressions
|
|
@cindex expressions, empty
|
|
An empty expression has no value: it is just whitespace or null.
|
|
Wherever an absolute expression is required, you may omit the
|
|
expression, and @code{@value{AS}} assumes a value of (absolute) 0. This
|
|
is compatible with other assemblers.
|
|
|
|
@node Integer Exprs
|
|
@section Integer Expressions
|
|
|
|
@cindex integer expressions
|
|
@cindex expressions, integer
|
|
An @dfn{integer expression} is one or more @emph{arguments} delimited
|
|
by @emph{operators}.
|
|
|
|
@menu
|
|
* Arguments:: Arguments
|
|
* Operators:: Operators
|
|
* Prefix Ops:: Prefix Operators
|
|
* Infix Ops:: Infix Operators
|
|
@end menu
|
|
|
|
@node Arguments
|
|
@subsection Arguments
|
|
|
|
@cindex expression arguments
|
|
@cindex arguments in expressions
|
|
@cindex operands in expressions
|
|
@cindex arithmetic operands
|
|
@dfn{Arguments} are symbols, numbers or subexpressions. In other
|
|
contexts arguments are sometimes called ``arithmetic operands''. In
|
|
this manual, to avoid confusing them with the ``instruction operands'' of
|
|
the machine language, we use the term ``argument'' to refer to parts of
|
|
expressions only, reserving the word ``operand'' to refer only to machine
|
|
instruction operands.
|
|
|
|
Symbols are evaluated to yield @{@var{section} @var{NNN}@} where
|
|
@var{section} is one of text, data, bss, absolute,
|
|
or undefined. @var{NNN} is a signed, 2's complement 32 bit
|
|
integer.
|
|
|
|
Numbers are usually integers.
|
|
|
|
A number can be a flonum or bignum. In this case, you are warned
|
|
that only the low order 32 bits are used, and @code{@value{AS}} pretends
|
|
these 32 bits are an integer. You may write integer-manipulating
|
|
instructions that act on exotic constants, compatible with other
|
|
assemblers.
|
|
|
|
@cindex subexpressions
|
|
Subexpressions are a left parenthesis @samp{(} followed by an integer
|
|
expression, followed by a right parenthesis @samp{)}; or a prefix
|
|
operator followed by an argument.
|
|
|
|
@node Operators
|
|
@subsection Operators
|
|
|
|
@cindex operators, in expressions
|
|
@cindex arithmetic functions
|
|
@cindex functions, in expressions
|
|
@dfn{Operators} are arithmetic functions, like @code{+} or @code{%}. Prefix
|
|
operators are followed by an argument. Infix operators appear
|
|
between their arguments. Operators may be preceded and/or followed by
|
|
whitespace.
|
|
|
|
@node Prefix Ops
|
|
@subsection Prefix Operator
|
|
|
|
@cindex prefix operators
|
|
@code{@value{AS}} has the following @dfn{prefix operators}. They each take
|
|
one argument, which must be absolute.
|
|
|
|
@c the tex/end tex stuff surrounding this small table is meant to make
|
|
@c it align, on the printed page, with the similar table in the next
|
|
@c section (which is inside an enumerate).
|
|
@tex
|
|
\global\advance\leftskip by \itemindent
|
|
@end tex
|
|
|
|
@table @code
|
|
@item -
|
|
@dfn{Negation}. Two's complement negation.
|
|
@item ~
|
|
@dfn{Complementation}. Bitwise not.
|
|
@end table
|
|
|
|
@tex
|
|
\global\advance\leftskip by -\itemindent
|
|
@end tex
|
|
|
|
@node Infix Ops
|
|
@subsection Infix Operators
|
|
|
|
@cindex infix operators
|
|
@cindex operators, permitted arguments
|
|
@dfn{Infix operators} take two arguments, one on either side. Operators
|
|
have precedence, but operations with equal precedence are performed left
|
|
to right. Apart from @code{+} or @code{-}, both arguments must be
|
|
absolute, and the result is absolute.
|
|
|
|
@enumerate
|
|
@cindex operator precedence
|
|
@cindex precedence of operators
|
|
|
|
@item
|
|
Highest Precedence
|
|
|
|
@table @code
|
|
@item *
|
|
@dfn{Multiplication}.
|
|
|
|
@item /
|
|
@dfn{Division}. Truncation is the same as the C operator @samp{/}
|
|
|
|
@item %
|
|
@dfn{Remainder}.
|
|
|
|
@item <
|
|
@itemx <<
|
|
@dfn{Shift Left}. Same as the C operator @samp{<<}.
|
|
|
|
@item >
|
|
@itemx >>
|
|
@dfn{Shift Right}. Same as the C operator @samp{>>}.
|
|
@end table
|
|
|
|
@item
|
|
Intermediate precedence
|
|
|
|
@table @code
|
|
@item |
|
|
|
|
@dfn{Bitwise Inclusive Or}.
|
|
|
|
@item &
|
|
@dfn{Bitwise And}.
|
|
|
|
@item ^
|
|
@dfn{Bitwise Exclusive Or}.
|
|
|
|
@item !
|
|
@dfn{Bitwise Or Not}.
|
|
@end table
|
|
|
|
@item
|
|
Lowest Precedence
|
|
|
|
@table @code
|
|
@item +
|
|
@cindex addition, permitted arguments
|
|
@cindex plus, permitted arguments
|
|
@cindex arguments for addition
|
|
@dfn{Addition}. If either argument is absolute, the result has the section of
|
|
the other argument. You may not add together arguments from different
|
|
sections.
|
|
|
|
@item -
|
|
@cindex subtraction, permitted arguments
|
|
@cindex minus, permitted arguments
|
|
@cindex arguments for subtraction
|
|
@dfn{Subtraction}. If the right argument is absolute, the
|
|
result has the section of the left argument.
|
|
If both arguments are in the same section, the result is absolute.
|
|
You may not subtract arguments from different sections.
|
|
@c FIXME is there still something useful to say about undefined - undefined ?
|
|
@end table
|
|
@end enumerate
|
|
|
|
In short, it's only meaningful to add or subtract the @emph{offsets} in an
|
|
address; you can only have a defined section in one of the two arguments.
|
|
|
|
@node Pseudo Ops
|
|
@chapter Assembler Directives
|
|
|
|
@cindex directives, machine independent
|
|
@cindex pseudo-ops, machine independent
|
|
@cindex machine independent directives
|
|
All assembler directives have names that begin with a period (@samp{.}).
|
|
The rest of the name is letters, usually in lower case.
|
|
|
|
This chapter discusses directives that are available regardless of the
|
|
target machine configuration for the @sc{gnu} assembler.
|
|
@ifset GENERIC
|
|
Some machine configurations provide additional directives.
|
|
@xref{Machine Dependencies}.
|
|
@end ifset
|
|
@ifclear GENERIC
|
|
@ifset machine-directives
|
|
@xref{Machine Dependencies} for additional directives.
|
|
@end ifset
|
|
@end ifclear
|
|
|
|
@menu
|
|
* Abort:: @code{.abort}
|
|
@ifset COFF
|
|
* ABORT:: @code{.ABORT}
|
|
@end ifset
|
|
|
|
* Align:: @code{.align @var{abs-expr} , @var{abs-expr}}
|
|
* App-File:: @code{.app-file @var{string}}
|
|
* Ascii:: @code{.ascii "@var{string}"}@dots{}
|
|
* Asciz:: @code{.asciz "@var{string}"}@dots{}
|
|
* Balign:: @code{.balign @var{abs-expr} , @var{abs-expr}}
|
|
* Byte:: @code{.byte @var{expressions}}
|
|
* Comm:: @code{.comm @var{symbol} , @var{length} }
|
|
* Data:: @code{.data @var{subsection}}
|
|
@ifset COFF
|
|
* Def:: @code{.def @var{name}}
|
|
@end ifset
|
|
@ifset aout-bout
|
|
* Desc:: @code{.desc @var{symbol}, @var{abs-expression}}
|
|
@end ifset
|
|
@ifset COFF
|
|
* Dim:: @code{.dim}
|
|
@end ifset
|
|
|
|
* Double:: @code{.double @var{flonums}}
|
|
* Eject:: @code{.eject}
|
|
* Else:: @code{.else}
|
|
@ifset COFF
|
|
* Endef:: @code{.endef}
|
|
@end ifset
|
|
|
|
* Endif:: @code{.endif}
|
|
* Equ:: @code{.equ @var{symbol}, @var{expression}}
|
|
* Extern:: @code{.extern}
|
|
@ifclear no-file-dir
|
|
* File:: @code{.file @var{string}}
|
|
@end ifclear
|
|
|
|
* Fill:: @code{.fill @var{repeat} , @var{size} , @var{value}}
|
|
* Float:: @code{.float @var{flonums}}
|
|
* Global:: @code{.global @var{symbol}}, @code{.globl @var{symbol}}
|
|
* hword:: @code{.hword @var{expressions}}
|
|
* Ident:: @code{.ident}
|
|
* If:: @code{.if @var{absolute expression}}
|
|
* Include:: @code{.include "@var{file}"}
|
|
* Int:: @code{.int @var{expressions}}
|
|
* Lcomm:: @code{.lcomm @var{symbol} , @var{length}}
|
|
* Lflags:: @code{.lflags}
|
|
@ifclear no-line-dir
|
|
* Line:: @code{.line @var{line-number}}
|
|
@end ifclear
|
|
|
|
* Ln:: @code{.ln @var{line-number}}
|
|
* List:: @code{.list}
|
|
* Long:: @code{.long @var{expressions}}
|
|
@ignore
|
|
* Lsym:: @code{.lsym @var{symbol}, @var{expression}}
|
|
@end ignore
|
|
|
|
* Nolist:: @code{.nolist}
|
|
* Octa:: @code{.octa @var{bignums}}
|
|
* Org:: @code{.org @var{new-lc} , @var{fill}}
|
|
* P2align:: @code{.p2align @var{abs-expr} , @var{abs-expr}}
|
|
* Psize:: @code{.psize @var{lines}, @var{columns}}
|
|
* Quad:: @code{.quad @var{bignums}}
|
|
* Sbttl:: @code{.sbttl "@var{subheading}"}
|
|
@ifset COFF
|
|
* Scl:: @code{.scl @var{class}}
|
|
@end ifset
|
|
@ifset COFF
|
|
* Section:: @code{.section @var{name}, @var{subsection}}
|
|
@end ifset
|
|
|
|
* Set:: @code{.set @var{symbol}, @var{expression}}
|
|
* Short:: @code{.short @var{expressions}}
|
|
* Single:: @code{.single @var{flonums}}
|
|
@ifset COFF
|
|
* Size:: @code{.size}
|
|
@end ifset
|
|
|
|
* Space:: @code{.space @var{size} , @var{fill}}
|
|
@ifset have-stabs
|
|
* Stab:: @code{.stabd, .stabn, .stabs}
|
|
@end ifset
|
|
|
|
* String:: @code{.string "@var{str}"}
|
|
@ifset COFF
|
|
* Tag:: @code{.tag @var{structname}}
|
|
@end ifset
|
|
|
|
* Text:: @code{.text @var{subsection}}
|
|
* Title:: @code{.title "@var{heading}"}
|
|
@ifset COFF
|
|
* Type:: @code{.type @var{int}}
|
|
* Val:: @code{.val @var{addr}}
|
|
@end ifset
|
|
|
|
* Word:: @code{.word @var{expressions}}
|
|
* Deprecated:: Deprecated Directives
|
|
@end menu
|
|
|
|
@node Abort
|
|
@section @code{.abort}
|
|
|
|
@cindex @code{abort} directive
|
|
@cindex stopping the assembly
|
|
This directive stops the assembly immediately. It is for
|
|
compatibility with other assemblers. The original idea was that the
|
|
assembly language source would be piped into the assembler. If the sender
|
|
of the source quit, it could use this directive tells @code{@value{AS}} to
|
|
quit also. One day @code{.abort} will not be supported.
|
|
|
|
@ifset COFF
|
|
@node ABORT
|
|
@section @code{.ABORT}
|
|
|
|
@cindex @code{ABORT} directive
|
|
When producing COFF output, @code{@value{AS}} accepts this directive as a
|
|
synonym for @samp{.abort}.
|
|
|
|
@ifset BOUT
|
|
When producing @code{b.out} output, @code{@value{AS}} accepts this directive,
|
|
but ignores it.
|
|
@end ifset
|
|
@end ifset
|
|
|
|
@node Align
|
|
@section @code{.align @var{abs-expr} , @var{abs-expr}}
|
|
|
|
@cindex padding the location counter
|
|
@cindex @code{align} directive
|
|
Pad the location counter (in the current subsection) to a particular
|
|
storage boundary. The first expression (which must be absolute) is the
|
|
alignment required, as described below.
|
|
The second expression (also absolute) gives the value to be stored in
|
|
the padding bytes. It (and the comma) may be omitted. If it is
|
|
omitted, the padding bytes are zero.
|
|
|
|
The way the required alignment is specified varies from system to system.
|
|
For the a29k, HPPA, m86k, m88k, w65, sparc, and i386 using ELF format,
|
|
the first expression is the
|
|
alignment request in bytes. For example @samp{.align 8} advances
|
|
the location counter until it is a multiple of 8. If the location counter
|
|
is already a multiple of 8, no change is needed.
|
|
|
|
For other systems, including the i386 using a.out format, it is the
|
|
number of low-order zero bits the location counter must have after
|
|
advancement. For example @samp{.align 3} advances the location
|
|
counter until it a multiple of 8. If the location counter is already a
|
|
multiple of 8, no change is needed.
|
|
|
|
This inconsistency is due to the different behaviors of the various
|
|
native assemblers for these systems which GAS must emulate.
|
|
GAS also provides @code{.balign} and @code{.p2align} directives,
|
|
described later, which have a consistent behavior across all
|
|
architectures (but are specific to GAS).
|
|
|
|
@node App-File
|
|
@section @code{.app-file @var{string}}
|
|
|
|
@cindex logical file name
|
|
@cindex file name, logical
|
|
@cindex @code{app-file} directive
|
|
@code{.app-file}
|
|
@ifclear no-file-dir
|
|
(which may also be spelled @samp{.file})
|
|
@end ifclear
|
|
tells @code{@value{AS}} that we are about to start a new
|
|
logical file. @var{string} is the new file name. In general, the
|
|
filename is recognized whether or not it is surrounded by quotes @samp{"};
|
|
but if you wish to specify an empty file name is permitted,
|
|
you must give the quotes--@code{""}. This statement may go away in
|
|
future: it is only recognized to be compatible with old @code{@value{AS}}
|
|
programs.@refill
|
|
|
|
@node Ascii
|
|
@section @code{.ascii "@var{string}"}@dots{}
|
|
|
|
@cindex @code{ascii} directive
|
|
@cindex string literals
|
|
@code{.ascii} expects zero or more string literals (@pxref{Strings})
|
|
separated by commas. It assembles each string (with no automatic
|
|
trailing zero byte) into consecutive addresses.
|
|
|
|
@node Asciz
|
|
@section @code{.asciz "@var{string}"}@dots{}
|
|
|
|
@cindex @code{asciz} directive
|
|
@cindex zero-terminated strings
|
|
@cindex null-terminated strings
|
|
@code{.asciz} is just like @code{.ascii}, but each string is followed by
|
|
a zero byte. The ``z'' in @samp{.asciz} stands for ``zero''.
|
|
|
|
@node Balign
|
|
@section @code{.balign @var{abs-expr} , @var{abs-expr}}
|
|
|
|
@cindex padding the location counter given number of bytes
|
|
@cindex @code{balign} directive
|
|
Pad the location counter (in the current subsection) to a particular
|
|
storage boundary. The first expression (which must be absolute) is the
|
|
alignment request in bytes. For example @samp{.balign 8} advances
|
|
the location counter until it is a multiple of 8. If the location counter
|
|
is already a multiple of 8, no change is needed.
|
|
|
|
The second expression (also absolute) gives the value to be stored in
|
|
the padding bytes. It (and the comma) may be omitted. If it is
|
|
omitted, the padding bytes are zero.
|
|
|
|
@node Byte
|
|
@section @code{.byte @var{expressions}}
|
|
|
|
@cindex @code{byte} directive
|
|
@cindex integers, one byte
|
|
@code{.byte} expects zero or more expressions, separated by commas.
|
|
Each expression is assembled into the next byte.
|
|
|
|
@node Comm
|
|
@section @code{.comm @var{symbol} , @var{length} }
|
|
|
|
@cindex @code{comm} directive
|
|
@cindex symbol, common
|
|
@code{.comm} declares a named common area in the bss section. Normally
|
|
@code{@value{LD}} reserves memory addresses for it during linking, so no partial
|
|
program defines the location of the symbol. Use @code{.comm} to tell
|
|
@code{@value{LD}} that it must be at least @var{length} bytes long. @code{@value{LD}}
|
|
allocates space for each @code{.comm} symbol that is at least as
|
|
long as the longest @code{.comm} request in any of the partial programs
|
|
linked. @var{length} is an absolute expression.
|
|
|
|
@ifset HPPA
|
|
The syntax for @code{.comm} differs slightly on the HPPA. The syntax is
|
|
@samp{@var{symbol} .comm, @var{length}}; @var{symbol} is optional.
|
|
@end ifset
|
|
|
|
@node Data
|
|
@section @code{.data @var{subsection}}
|
|
|
|
@cindex @code{data} directive
|
|
@code{.data} tells @code{@value{AS}} to assemble the following statements onto the
|
|
end of the data subsection numbered @var{subsection} (which is an
|
|
absolute expression). If @var{subsection} is omitted, it defaults
|
|
to zero.
|
|
|
|
@ifset COFF
|
|
@node Def
|
|
@section @code{.def @var{name}}
|
|
|
|
@cindex @code{def} directive
|
|
@cindex COFF symbols, debugging
|
|
@cindex debugging COFF symbols
|
|
Begin defining debugging information for a symbol @var{name}; the
|
|
definition extends until the @code{.endef} directive is encountered.
|
|
@ifset BOUT
|
|
|
|
This directive is only observed when @code{@value{AS}} is configured for COFF
|
|
format output; when producing @code{b.out}, @samp{.def} is recognized,
|
|
but ignored.
|
|
@end ifset
|
|
@end ifset
|
|
|
|
@ifset aout-bout
|
|
@node Desc
|
|
@section @code{.desc @var{symbol}, @var{abs-expression}}
|
|
|
|
@cindex @code{desc} directive
|
|
@cindex COFF symbol descriptor
|
|
@cindex symbol descriptor, COFF
|
|
This directive sets the descriptor of the symbol (@pxref{Symbol Attributes})
|
|
to the low 16 bits of an absolute expression.
|
|
|
|
@ifset COFF
|
|
The @samp{.desc} directive is not available when @code{@value{AS}} is
|
|
configured for COFF output; it is only for @code{a.out} or @code{b.out}
|
|
object format. For the sake of compatibility, @code{@value{AS}} accepts
|
|
it, but produces no output, when configured for COFF.
|
|
@end ifset
|
|
@end ifset
|
|
|
|
@ifset COFF
|
|
@node Dim
|
|
@section @code{.dim}
|
|
|
|
@cindex @code{dim} directive
|
|
@cindex COFF auxiliary symbol information
|
|
@cindex auxiliary symbol information, COFF
|
|
This directive is generated by compilers to include auxiliary debugging
|
|
information in the symbol table. It is only permitted inside
|
|
@code{.def}/@code{.endef} pairs.
|
|
@ifset BOUT
|
|
|
|
@samp{.dim} is only meaningful when generating COFF format output; when
|
|
@code{@value{AS}} is generating @code{b.out}, it accepts this directive but
|
|
ignores it.
|
|
@end ifset
|
|
@end ifset
|
|
|
|
@node Double
|
|
@section @code{.double @var{flonums}}
|
|
|
|
@cindex @code{double} directive
|
|
@cindex floating point numbers (double)
|
|
@code{.double} expects zero or more flonums, separated by commas. It
|
|
assembles floating point numbers.
|
|
@ifset GENERIC
|
|
The exact kind of floating point numbers emitted depends on how
|
|
@code{@value{AS}} is configured. @xref{Machine Dependencies}.
|
|
@end ifset
|
|
@ifclear GENERIC
|
|
@ifset IEEEFLOAT
|
|
On the @value{TARGET} family @samp{.double} emits 64-bit floating-point numbers
|
|
in @sc{ieee} format.
|
|
@end ifset
|
|
@end ifclear
|
|
|
|
@node Eject
|
|
@section @code{.eject}
|
|
|
|
@cindex @code{eject} directive
|
|
@cindex new page, in listings
|
|
@cindex page, in listings
|
|
@cindex listing control: new page
|
|
Force a page break at this point, when generating assembly listings.
|
|
|
|
@node Else
|
|
@section @code{.else}
|
|
|
|
@cindex @code{else} directive
|
|
@code{.else} is part of the @code{@value{AS}} support for conditional
|
|
assembly; @pxref{If,,@code{.if}}. It marks the beginning of a section
|
|
of code to be assembled if the condition for the preceding @code{.if}
|
|
was false.
|
|
|
|
@ignore
|
|
@node End, Endef, Else, Pseudo Ops
|
|
@section @code{.end}
|
|
|
|
@cindex @code{end} directive
|
|
This doesn't do anything---but isn't an s_ignore, so I suspect it's
|
|
meant to do something eventually (which is why it isn't documented here
|
|
as "for compatibility with blah").
|
|
@end ignore
|
|
|
|
@ifset COFF
|
|
@node Endef
|
|
@section @code{.endef}
|
|
|
|
@cindex @code{endef} directive
|
|
This directive flags the end of a symbol definition begun with
|
|
@code{.def}.
|
|
@ifset BOUT
|
|
|
|
@samp{.endef} is only meaningful when generating COFF format output; if
|
|
@code{@value{AS}} is configured to generate @code{b.out}, it accepts this
|
|
directive but ignores it.
|
|
@end ifset
|
|
@end ifset
|
|
|
|
@node Endif
|
|
@section @code{.endif}
|
|
|
|
@cindex @code{endif} directive
|
|
@code{.endif} is part of the @code{@value{AS}} support for conditional assembly;
|
|
it marks the end of a block of code that is only assembled
|
|
conditionally. @xref{If,,@code{.if}}.
|
|
|
|
@node Equ
|
|
@section @code{.equ @var{symbol}, @var{expression}}
|
|
|
|
@cindex @code{equ} directive
|
|
@cindex assigning values to symbols
|
|
@cindex symbols, assigning values to
|
|
This directive sets the value of @var{symbol} to @var{expression}.
|
|
It is synonymous with @samp{.set}; @pxref{Set,,@code{.set}}.
|
|
|
|
@ifset HPPA
|
|
The syntax for @code{equ} on the HPPA is
|
|
@samp{@var{symbol} .equ @var{expression}}.
|
|
@end ifset
|
|
|
|
@node Extern
|
|
@section @code{.extern}
|
|
|
|
@cindex @code{extern} directive
|
|
@code{.extern} is accepted in the source program---for compatibility
|
|
with other assemblers---but it is ignored. @code{@value{AS}} treats
|
|
all undefined symbols as external.
|
|
|
|
@ifclear no-file-dir
|
|
@node File
|
|
@section @code{.file @var{string}}
|
|
|
|
@cindex @code{file} directive
|
|
@cindex logical file name
|
|
@cindex file name, logical
|
|
@code{.file} (which may also be spelled @samp{.app-file}) tells
|
|
@code{@value{AS}} that we are about to start a new logical file.
|
|
@var{string} is the new file name. In general, the filename is
|
|
recognized whether or not it is surrounded by quotes @samp{"}; but if
|
|
you wish to specify an empty file name, you must give the
|
|
quotes--@code{""}. This statement may go away in future: it is only
|
|
recognized to be compatible with old @code{@value{AS}} programs.
|
|
@ifset A29K
|
|
In some configurations of @code{@value{AS}}, @code{.file} has already been
|
|
removed to avoid conflicts with other assemblers. @xref{Machine Dependencies}.
|
|
@end ifset
|
|
@end ifclear
|
|
|
|
@node Fill
|
|
@section @code{.fill @var{repeat} , @var{size} , @var{value}}
|
|
|
|
@cindex @code{fill} directive
|
|
@cindex writing patterns in memory
|
|
@cindex patterns, writing in memory
|
|
@var{result}, @var{size} and @var{value} are absolute expressions.
|
|
This emits @var{repeat} copies of @var{size} bytes. @var{Repeat}
|
|
may be zero or more. @var{Size} may be zero or more, but if it is
|
|
more than 8, then it is deemed to have the value 8, compatible with
|
|
other people's assemblers. The contents of each @var{repeat} bytes
|
|
is taken from an 8-byte number. The highest order 4 bytes are
|
|
zero. The lowest order 4 bytes are @var{value} rendered in the
|
|
byte-order of an integer on the computer @code{@value{AS}} is assembling for.
|
|
Each @var{size} bytes in a repetition is taken from the lowest order
|
|
@var{size} bytes of this number. Again, this bizarre behavior is
|
|
compatible with other people's assemblers.
|
|
|
|
@var{size} and @var{value} are optional.
|
|
If the second comma and @var{value} are absent, @var{value} is
|
|
assumed zero. If the first comma and following tokens are absent,
|
|
@var{size} is assumed to be 1.
|
|
|
|
@node Float
|
|
@section @code{.float @var{flonums}}
|
|
|
|
@cindex floating point numbers (single)
|
|
@cindex @code{float} directive
|
|
This directive assembles zero or more flonums, separated by commas. It
|
|
has the same effect as @code{.single}.
|
|
@ifset GENERIC
|
|
The exact kind of floating point numbers emitted depends on how
|
|
@code{@value{AS}} is configured.
|
|
@xref{Machine Dependencies}.
|
|
@end ifset
|
|
@ifclear GENERIC
|
|
@ifset IEEEFLOAT
|
|
On the @value{TARGET} family, @code{.float} emits 32-bit floating point numbers
|
|
in @sc{ieee} format.
|
|
@end ifset
|
|
@end ifclear
|
|
|
|
@node Global
|
|
@section @code{.global @var{symbol}}, @code{.globl @var{symbol}}
|
|
|
|
@cindex @code{global} directive
|
|
@cindex symbol, making visible to linker
|
|
@code{.global} makes the symbol visible to @code{@value{LD}}. If you define
|
|
@var{symbol} in your partial program, its value is made available to
|
|
other partial programs that are linked with it. Otherwise,
|
|
@var{symbol} takes its attributes from a symbol of the same name
|
|
from another file linked into the same program.
|
|
|
|
Both spellings (@samp{.globl} and @samp{.global}) are accepted, for
|
|
compatibility with other assemblers.
|
|
|
|
@ifset HPPA
|
|
On the HPPA, @code{.global} is not always enough to make it accessible to other
|
|
partial programs. You may need the HPPA-only @code{.EXPORT} directive as well.
|
|
@xref{HPPA Directives,, HPPA Assembler Directives}.
|
|
@end ifset
|
|
|
|
@node hword
|
|
@section @code{.hword @var{expressions}}
|
|
|
|
@cindex @code{hword} directive
|
|
@cindex integers, 16-bit
|
|
@cindex numbers, 16-bit
|
|
@cindex sixteen bit integers
|
|
This expects zero or more @var{expressions}, and emits
|
|
a 16 bit number for each.
|
|
|
|
@ifset GENERIC
|
|
This directive is a synonym for @samp{.short}; depending on the target
|
|
architecture, it may also be a synonym for @samp{.word}.
|
|
@end ifset
|
|
@ifclear GENERIC
|
|
@ifset W32
|
|
This directive is a synonym for @samp{.short}.
|
|
@end ifset
|
|
@ifset W16
|
|
This directive is a synonym for both @samp{.short} and @samp{.word}.
|
|
@end ifset
|
|
@end ifclear
|
|
|
|
@node Ident
|
|
@section @code{.ident}
|
|
|
|
@cindex @code{ident} directive
|
|
This directive is used by some assemblers to place tags in object files.
|
|
@code{@value{AS}} simply accepts the directive for source-file
|
|
compatibility with such assemblers, but does not actually emit anything
|
|
for it.
|
|
|
|
@node If
|
|
@section @code{.if @var{absolute expression}}
|
|
|
|
@cindex conditional assembly
|
|
@cindex @code{if} directive
|
|
@code{.if} marks the beginning of a section of code which is only
|
|
considered part of the source program being assembled if the argument
|
|
(which must be an @var{absolute expression}) is non-zero. The end of
|
|
the conditional section of code must be marked by @code{.endif}
|
|
(@pxref{Endif,,@code{.endif}}); optionally, you may include code for the
|
|
alternative condition, flagged by @code{.else} (@pxref{Else,,@code{.else}}.
|
|
|
|
The following variants of @code{.if} are also supported:
|
|
@table @code
|
|
@item .ifdef @var{symbol}
|
|
@cindex @code{ifdef} directive
|
|
Assembles the following section of code if the specified @var{symbol}
|
|
has been defined.
|
|
|
|
@ignore
|
|
@item .ifeqs
|
|
@cindex @code{ifeqs} directive
|
|
Not yet implemented.
|
|
@end ignore
|
|
|
|
@item .ifndef @var{symbol}
|
|
@itemx ifnotdef @var{symbol}
|
|
@cindex @code{ifndef} directive
|
|
@cindex @code{ifnotdef} directive
|
|
Assembles the following section of code if the specified @var{symbol}
|
|
has not been defined. Both spelling variants are equivalent.
|
|
|
|
@ignore
|
|
@item ifnes
|
|
Not yet implemented.
|
|
@end ignore
|
|
@end table
|
|
|
|
@node Include
|
|
@section @code{.include "@var{file}"}
|
|
|
|
@cindex @code{include} directive
|
|
@cindex supporting files, including
|
|
@cindex files, including
|
|
This directive provides a way to include supporting files at specified
|
|
points in your source program. The code from @var{file} is assembled as
|
|
if it followed the point of the @code{.include}; when the end of the
|
|
included file is reached, assembly of the original file continues. You
|
|
can control the search paths used with the @samp{-I} command-line option
|
|
(@pxref{Invoking,,Command-Line Options}). Quotation marks are required
|
|
around @var{file}.
|
|
|
|
@node Int
|
|
@section @code{.int @var{expressions}}
|
|
|
|
@cindex @code{int} directive
|
|
@cindex integers, 32-bit
|
|
Expect zero or more @var{expressions}, of any section, separated by commas.
|
|
For each expression, emit a number that, at run time, is the value of that
|
|
expression. The byte order and bit size of the number depends on what kind
|
|
of target the assembly is for.
|
|
|
|
@ifclear GENERIC
|
|
@ifset H8
|
|
On the H8/500 and most forms of the H8/300, @code{.int} emits 16-bit
|
|
integers. On the H8/300H and the Hitachi SH, however, @code{.int} emits
|
|
32-bit integers.
|
|
@end ifset
|
|
@end ifclear
|
|
|
|
@node Lcomm
|
|
@section @code{.lcomm @var{symbol} , @var{length}}
|
|
|
|
@cindex @code{lcomm} directive
|
|
@cindex local common symbols
|
|
@cindex symbols, local common
|
|
Reserve @var{length} (an absolute expression) bytes for a local common
|
|
denoted by @var{symbol}. The section and value of @var{symbol} are
|
|
those of the new local common. The addresses are allocated in the bss
|
|
section, so that at run-time the bytes start off zeroed. @var{Symbol}
|
|
is not declared global (@pxref{Global,,@code{.global}}), so is normally
|
|
not visible to @code{@value{LD}}.
|
|
|
|
@ifset HPPA
|
|
The syntax for @code{.lcomm} differs slightly on the HPPA. The syntax is
|
|
@samp{@var{symbol} .lcomm, @var{length}}; @var{symbol} is optional.
|
|
@end ifset
|
|
|
|
@node Lflags
|
|
@section @code{.lflags}
|
|
|
|
@cindex @code{lflags} directive (ignored)
|
|
@code{@value{AS}} accepts this directive, for compatibility with other
|
|
assemblers, but ignores it.
|
|
|
|
@ifclear no-line-dir
|
|
@node Line
|
|
@section @code{.line @var{line-number}}
|
|
|
|
@cindex @code{line} directive
|
|
@end ifclear
|
|
@ifset no-line-dir
|
|
@node Ln
|
|
@section @code{.ln @var{line-number}}
|
|
|
|
@cindex @code{ln} directive
|
|
@end ifset
|
|
@cindex logical line number
|
|
@ifset aout-bout
|
|
Change the logical line number. @var{line-number} must be an absolute
|
|
expression. The next line has that logical line number. Therefore any other
|
|
statements on the current line (after a statement separator character) are
|
|
reported as on logical line number @var{line-number} @minus{} 1. One day
|
|
@code{@value{AS}} will no longer support this directive: it is recognized only
|
|
for compatibility with existing assembler programs.
|
|
|
|
@ifset GENERIC
|
|
@ifset A29K
|
|
@emph{Warning:} In the AMD29K configuration of @value{AS}, this command is
|
|
not available; use the synonym @code{.ln} in that context.
|
|
@end ifset
|
|
@end ifset
|
|
@end ifset
|
|
|
|
@ifclear no-line-dir
|
|
Even though this is a directive associated with the @code{a.out} or
|
|
@code{b.out} object-code formats, @code{@value{AS}} still recognizes it
|
|
when producing COFF output, and treats @samp{.line} as though it
|
|
were the COFF @samp{.ln} @emph{if} it is found outside a
|
|
@code{.def}/@code{.endef} pair.
|
|
|
|
Inside a @code{.def}, @samp{.line} is, instead, one of the directives
|
|
used by compilers to generate auxiliary symbol information for
|
|
debugging.
|
|
@end ifclear
|
|
|
|
@node Ln
|
|
@section @code{.ln @var{line-number}}
|
|
|
|
@cindex @code{ln} directive
|
|
@ifclear no-line-dir
|
|
@samp{.ln} is a synonym for @samp{.line}.
|
|
@end ifclear
|
|
@ifset no-line-dir
|
|
Tell @code{@value{AS}} to change the logical line number. @var{line-number}
|
|
must be an absolute expression. The next line has that logical
|
|
line number, so any other statements on the current line (after a
|
|
statement separator character @code{;}) are reported as on logical
|
|
line number @var{line-number} @minus{} 1.
|
|
@ifset BOUT
|
|
|
|
This directive is accepted, but ignored, when @code{@value{AS}} is
|
|
configured for @code{b.out}; its effect is only associated with COFF
|
|
output format.
|
|
@end ifset
|
|
@end ifset
|
|
|
|
@node List
|
|
@section @code{.list}
|
|
|
|
@cindex @code{list} directive
|
|
@cindex listing control, turning on
|
|
Control (in conjunction with the @code{.nolist} directive) whether or
|
|
not assembly listings are generated. These two directives maintain an
|
|
internal counter (which is zero initially). @code{.list} increments the
|
|
counter, and @code{.nolist} decrements it. Assembly listings are
|
|
generated whenever the counter is greater than zero.
|
|
|
|
By default, listings are disabled. When you enable them (with the
|
|
@samp{-a} command line option; @pxref{Invoking,,Command-Line Options}),
|
|
the initial value of the listing counter is one.
|
|
|
|
@node Long
|
|
@section @code{.long @var{expressions}}
|
|
|
|
@cindex @code{long} directive
|
|
@code{.long} is the same as @samp{.int}, @pxref{Int,,@code{.int}}.
|
|
|
|
@ignore
|
|
@c no one seems to know what this is for or whether this description is
|
|
@c what it really ought to do
|
|
@node Lsym
|
|
@section @code{.lsym @var{symbol}, @var{expression}}
|
|
|
|
@cindex @code{lsym} directive
|
|
@cindex symbol, not referenced in assembly
|
|
@code{.lsym} creates a new symbol named @var{symbol}, but does not put it in
|
|
the hash table, ensuring it cannot be referenced by name during the
|
|
rest of the assembly. This sets the attributes of the symbol to be
|
|
the same as the expression value:
|
|
@smallexample
|
|
@var{other} = @var{descriptor} = 0
|
|
@var{type} = @r{(section of @var{expression})}
|
|
@var{value} = @var{expression}
|
|
@end smallexample
|
|
@noindent
|
|
The new symbol is not flagged as external.
|
|
@end ignore
|
|
|
|
@node Nolist
|
|
@section @code{.nolist}
|
|
|
|
@cindex @code{nolist} directive
|
|
@cindex listing control, turning off
|
|
Control (in conjunction with the @code{.list} directive) whether or
|
|
not assembly listings are generated. These two directives maintain an
|
|
internal counter (which is zero initially). @code{.list} increments the
|
|
counter, and @code{.nolist} decrements it. Assembly listings are
|
|
generated whenever the counter is greater than zero.
|
|
|
|
@node Octa
|
|
@section @code{.octa @var{bignums}}
|
|
|
|
@c FIXME: double size emitted for "octa" on i960, others? Or warn?
|
|
@cindex @code{octa} directive
|
|
@cindex integer, 16-byte
|
|
@cindex sixteen byte integer
|
|
This directive expects zero or more bignums, separated by commas. For each
|
|
bignum, it emits a 16-byte integer.
|
|
|
|
The term ``octa'' comes from contexts in which a ``word'' is two bytes;
|
|
hence @emph{octa}-word for 16 bytes.
|
|
|
|
@node Org
|
|
@section @code{.org @var{new-lc} , @var{fill}}
|
|
|
|
@cindex @code{org} directive
|
|
@cindex location counter, advancing
|
|
@cindex advancing location counter
|
|
@cindex current address, advancing
|
|
Advance the location counter of the current section to
|
|
@var{new-lc}. @var{new-lc} is either an absolute expression or an
|
|
expression with the same section as the current subsection. That is,
|
|
you can't use @code{.org} to cross sections: if @var{new-lc} has the
|
|
wrong section, the @code{.org} directive is ignored. To be compatible
|
|
with former assemblers, if the section of @var{new-lc} is absolute,
|
|
@code{@value{AS}} issues a warning, then pretends the section of @var{new-lc}
|
|
is the same as the current subsection.
|
|
|
|
@code{.org} may only increase the location counter, or leave it
|
|
unchanged; you cannot use @code{.org} to move the location counter
|
|
backwards.
|
|
|
|
@c double negative used below "not undefined" because this is a specific
|
|
@c reference to "undefined" (as SEG_UNKNOWN is called in this manual)
|
|
@c section. pesch@cygnus.com 18feb91
|
|
Because @code{@value{AS}} tries to assemble programs in one pass, @var{new-lc}
|
|
may not be undefined. If you really detest this restriction we eagerly await
|
|
a chance to share your improved assembler.
|
|
|
|
Beware that the origin is relative to the start of the section, not
|
|
to the start of the subsection. This is compatible with other
|
|
people's assemblers.
|
|
|
|
When the location counter (of the current subsection) is advanced, the
|
|
intervening bytes are filled with @var{fill} which should be an
|
|
absolute expression. If the comma and @var{fill} are omitted,
|
|
@var{fill} defaults to zero.
|
|
|
|
@node P2align
|
|
@section @code{.p2align @var{abs-expr} , @var{abs-expr}}
|
|
|
|
@cindex padding the location counter given a power of two
|
|
@cindex @code{p2align} directive
|
|
Pad the location counter (in the current subsection) to a particular
|
|
storage boundary. The first expression (which must be absolute) is the
|
|
number of low-order zero bits the location counter must have after
|
|
advancement. For example @samp{.p2align 3} advances the location
|
|
counter until it a multiple of 8. If the location counter is already a
|
|
multiple of 8, no change is needed.
|
|
|
|
The second expression (also absolute) gives the value to be stored in
|
|
the padding bytes. It (and the comma) may be omitted. If it is
|
|
omitted, the padding bytes are zero.
|
|
|
|
@node Psize
|
|
@section @code{.psize @var{lines} , @var{columns}}
|
|
|
|
@cindex @code{psize} directive
|
|
@cindex listing control: paper size
|
|
@cindex paper size, for listings
|
|
Use this directive to declare the number of lines---and, optionally, the
|
|
number of columns---to use for each page, when generating listings.
|
|
|
|
If you do not use @code{.psize}, listings use a default line-count
|
|
of 60. You may omit the comma and @var{columns} specification; the
|
|
default width is 200 columns.
|
|
|
|
@code{@value{AS}} generates formfeeds whenever the specified number of
|
|
lines is exceeded (or whenever you explicitly request one, using
|
|
@code{.eject}).
|
|
|
|
If you specify @var{lines} as @code{0}, no formfeeds are generated save
|
|
those explicitly specified with @code{.eject}.
|
|
|
|
@node Quad
|
|
@section @code{.quad @var{bignums}}
|
|
|
|
@cindex @code{quad} directive
|
|
@code{.quad} expects zero or more bignums, separated by commas. For
|
|
each bignum, it emits
|
|
@ifclear bignum-16
|
|
an 8-byte integer. If the bignum won't fit in 8 bytes, it prints a
|
|
warning message; and just takes the lowest order 8 bytes of the bignum.
|
|
@cindex eight-byte integer
|
|
@cindex integer, 8-byte
|
|
|
|
The term ``quad'' comes from contexts in which a ``word'' is two bytes;
|
|
hence @emph{quad}-word for 8 bytes.
|
|
@end ifclear
|
|
@ifset bignum-16
|
|
a 16-byte integer. If the bignum won't fit in 16 bytes, it prints a
|
|
warning message; and just takes the lowest order 16 bytes of the bignum.
|
|
@cindex sixteen-byte integer
|
|
@cindex integer, 16-byte
|
|
@end ifset
|
|
|
|
@node Sbttl
|
|
@section @code{.sbttl "@var{subheading}"}
|
|
|
|
@cindex @code{sbttl} directive
|
|
@cindex subtitles for listings
|
|
@cindex listing control: subtitle
|
|
Use @var{subheading} as the title (third line, immediately after the
|
|
title line) when generating assembly listings.
|
|
|
|
This directive affects subsequent pages, as well as the current page if
|
|
it appears within ten lines of the top of a page.
|
|
|
|
@ifset COFF
|
|
@node Scl
|
|
@section @code{.scl @var{class}}
|
|
|
|
@cindex @code{scl} directive
|
|
@cindex symbol storage class (COFF)
|
|
@cindex COFF symbol storage class
|
|
Set the storage-class value for a symbol. This directive may only be
|
|
used inside a @code{.def}/@code{.endef} pair. Storage class may flag
|
|
whether a symbol is static or external, or it may record further
|
|
symbolic debugging information.
|
|
@ifset BOUT
|
|
|
|
The @samp{.scl} directive is primarily associated with COFF output; when
|
|
configured to generate @code{b.out} output format, @code{@value{AS}}
|
|
accepts this directive but ignores it.
|
|
@end ifset
|
|
@end ifset
|
|
|
|
@ifset COFF
|
|
@node Section
|
|
@section @code{.section @var{name}, @var{subsection}}
|
|
|
|
@cindex @code{section} directive
|
|
@cindex named section (COFF)
|
|
@cindex COFF named section
|
|
Assemble the following code into end of subsection numbered
|
|
@var{subsection} in the COFF named section @var{name}. If you omit
|
|
@var{subsection}, @code{@value{AS}} uses subsection number zero.
|
|
@samp{.section .text} is equivalent to the @code{.text} directive;
|
|
@samp{.section .data} is equivalent to the @code{.data} directive.
|
|
@ifset GENERIC
|
|
This directive is only supported for targets that actually support arbitrarily
|
|
named sections; on @code{a.out} targets, for example, it is not accepted, even
|
|
with a standard @code{a.out} section name as its parameter.
|
|
@end ifset
|
|
@end ifset
|
|
|
|
@node Set
|
|
@section @code{.set @var{symbol}, @var{expression}}
|
|
|
|
@cindex @code{set} directive
|
|
@cindex symbol value, setting
|
|
Set the value of @var{symbol} to @var{expression}. This
|
|
changes @var{symbol}'s value and type to conform to
|
|
@var{expression}. If @var{symbol} was flagged as external, it remains
|
|
flagged. (@xref{Symbol Attributes}.)
|
|
|
|
You may @code{.set} a symbol many times in the same assembly.
|
|
|
|
If you @code{.set} a global symbol, the value stored in the object
|
|
file is the last value stored into it.
|
|
|
|
@ifset HPPA
|
|
The syntax for @code{set} on the HPPA is
|
|
@samp{@var{symbol} .set @var{expression}}.
|
|
@end ifset
|
|
|
|
@node Short
|
|
@section @code{.short @var{expressions}}
|
|
|
|
@cindex @code{short} directive
|
|
@ifset GENERIC
|
|
@code{.short} is normally the same as @samp{.word}.
|
|
@xref{Word,,@code{.word}}.
|
|
|
|
In some configurations, however, @code{.short} and @code{.word} generate
|
|
numbers of different lengths; @pxref{Machine Dependencies}.
|
|
@end ifset
|
|
@ifclear GENERIC
|
|
@ifset W16
|
|
@code{.short} is the same as @samp{.word}. @xref{Word,,@code{.word}}.
|
|
@end ifset
|
|
@ifset W32
|
|
This expects zero or more @var{expressions}, and emits
|
|
a 16 bit number for each.
|
|
@end ifset
|
|
@end ifclear
|
|
|
|
@node Single
|
|
@section @code{.single @var{flonums}}
|
|
|
|
@cindex @code{single} directive
|
|
@cindex floating point numbers (single)
|
|
This directive assembles zero or more flonums, separated by commas. It
|
|
has the same effect as @code{.float}.
|
|
@ifset GENERIC
|
|
The exact kind of floating point numbers emitted depends on how
|
|
@code{@value{AS}} is configured. @xref{Machine Dependencies}.
|
|
@end ifset
|
|
@ifclear GENERIC
|
|
@ifset IEEEFLOAT
|
|
On the @value{TARGET} family, @code{.single} emits 32-bit floating point
|
|
numbers in @sc{ieee} format.
|
|
@end ifset
|
|
@end ifclear
|
|
|
|
@ifset COFF
|
|
@node Size
|
|
@section @code{.size}
|
|
|
|
@cindex @code{size} directive
|
|
This directive is generated by compilers to include auxiliary debugging
|
|
information in the symbol table. It is only permitted inside
|
|
@code{.def}/@code{.endef} pairs.
|
|
@ifset BOUT
|
|
|
|
@samp{.size} is only meaningful when generating COFF format output; when
|
|
@code{@value{AS}} is generating @code{b.out}, it accepts this directive but
|
|
ignores it.
|
|
@end ifset
|
|
@end ifset
|
|
|
|
@ifclear no-space-dir
|
|
@node Space
|
|
@section @code{.space @var{size} , @var{fill}}
|
|
|
|
@cindex @code{space} directive
|
|
@cindex filling memory
|
|
This directive emits @var{size} bytes, each of value @var{fill}. Both
|
|
@var{size} and @var{fill} are absolute expressions. If the comma
|
|
and @var{fill} are omitted, @var{fill} is assumed to be zero.
|
|
|
|
@ifset HPPA
|
|
@quotation
|
|
@emph{Warning:} @code{.space} has a completely different meaning for HPPA
|
|
targets; use @code{.block} as a substitute. See @cite{HP9000 Series 800
|
|
Assembly Language Reference Manual} (HP 92432-90001) for the meaning of the
|
|
@code{.space} directive. @xref{HPPA Directives,,HPPA Assembler Directives},
|
|
for a summary.
|
|
@end quotation
|
|
@end ifset
|
|
@end ifclear
|
|
|
|
@ifset A29K
|
|
@ifclear GENERIC
|
|
@node Space
|
|
@section @code{.space}
|
|
@cindex @code{space} directive
|
|
@end ifclear
|
|
On the AMD 29K, this directive is ignored; it is accepted for
|
|
compatibility with other AMD 29K assemblers.
|
|
|
|
@quotation
|
|
@emph{Warning:} In most versions of the @sc{gnu} assembler, the directive
|
|
@code{.space} has the effect of @code{.block} @xref{Machine Dependencies}.
|
|
@end quotation
|
|
@end ifset
|
|
|
|
@ifset have-stabs
|
|
@node Stab
|
|
@section @code{.stabd, .stabn, .stabs}
|
|
|
|
@cindex symbolic debuggers, information for
|
|
@cindex @code{stab@var{x}} directives
|
|
There are three directives that begin @samp{.stab}.
|
|
All emit symbols (@pxref{Symbols}), for use by symbolic debuggers.
|
|
The symbols are not entered in the @code{@value{AS}} hash table: they
|
|
cannot be referenced elsewhere in the source file.
|
|
Up to five fields are required:
|
|
|
|
@table @var
|
|
@item string
|
|
This is the symbol's name. It may contain any character except
|
|
@samp{\000}, so is more general than ordinary symbol names. Some
|
|
debuggers used to code arbitrarily complex structures into symbol names
|
|
using this field.
|
|
|
|
@item type
|
|
An absolute expression. The symbol's type is set to the low 8 bits of
|
|
this expression. Any bit pattern is permitted, but @code{@value{LD}}
|
|
and debuggers choke on silly bit patterns.
|
|
|
|
@item other
|
|
An absolute expression. The symbol's ``other'' attribute is set to the
|
|
low 8 bits of this expression.
|
|
|
|
@item desc
|
|
An absolute expression. The symbol's descriptor is set to the low 16
|
|
bits of this expression.
|
|
|
|
@item value
|
|
An absolute expression which becomes the symbol's value.
|
|
@end table
|
|
|
|
If a warning is detected while reading a @code{.stabd}, @code{.stabn},
|
|
or @code{.stabs} statement, the symbol has probably already been created;
|
|
you get a half-formed symbol in your object file. This is
|
|
compatible with earlier assemblers!
|
|
|
|
@table @code
|
|
@cindex @code{stabd} directive
|
|
@item .stabd @var{type} , @var{other} , @var{desc}
|
|
|
|
The ``name'' of the symbol generated is not even an empty string.
|
|
It is a null pointer, for compatibility. Older assemblers used a
|
|
null pointer so they didn't waste space in object files with empty
|
|
strings.
|
|
|
|
The symbol's value is set to the location counter,
|
|
relocatably. When your program is linked, the value of this symbol
|
|
is the address of the location counter when the @code{.stabd} was
|
|
assembled.
|
|
|
|
@item .stabn @var{type} , @var{other} , @var{desc} , @var{value}
|
|
@cindex @code{stabn} directive
|
|
The name of the symbol is set to the empty string @code{""}.
|
|
|
|
@item .stabs @var{string} , @var{type} , @var{other} , @var{desc} , @var{value}
|
|
@cindex @code{stabs} directive
|
|
All five fields are specified.
|
|
@end table
|
|
@end ifset
|
|
@c end have-stabs
|
|
|
|
@node String
|
|
@section @code{.string} "@var{str}"
|
|
|
|
@cindex string, copying to object file
|
|
@cindex @code{string} directive
|
|
|
|
Copy the characters in @var{str} to the object file. You may specify more than
|
|
one string to copy, separated by commas. Unless otherwise specified for a
|
|
particular machine, the assembler marks the end of each string with a 0 byte.
|
|
You can use any of the escape sequences described in @ref{Strings,,Strings}.
|
|
|
|
@ifset COFF
|
|
@node Tag
|
|
@section @code{.tag @var{structname}}
|
|
|
|
@cindex COFF structure debugging
|
|
@cindex structure debugging, COFF
|
|
@cindex @code{tag} directive
|
|
This directive is generated by compilers to include auxiliary debugging
|
|
information in the symbol table. It is only permitted inside
|
|
@code{.def}/@code{.endef} pairs. Tags are used to link structure
|
|
definitions in the symbol table with instances of those structures.
|
|
@ifset BOUT
|
|
|
|
@samp{.tag} is only used when generating COFF format output; when
|
|
@code{@value{AS}} is generating @code{b.out}, it accepts this directive but
|
|
ignores it.
|
|
@end ifset
|
|
@end ifset
|
|
|
|
@node Text
|
|
@section @code{.text @var{subsection}}
|
|
|
|
@cindex @code{text} directive
|
|
Tells @code{@value{AS}} to assemble the following statements onto the end of
|
|
the text subsection numbered @var{subsection}, which is an absolute
|
|
expression. If @var{subsection} is omitted, subsection number zero
|
|
is used.
|
|
|
|
@node Title
|
|
@section @code{.title "@var{heading}"}
|
|
|
|
@cindex @code{title} directive
|
|
@cindex listing control: title line
|
|
Use @var{heading} as the title (second line, immediately after the
|
|
source file name and pagenumber) when generating assembly listings.
|
|
|
|
This directive affects subsequent pages, as well as the current page if
|
|
it appears within ten lines of the top of a page.
|
|
|
|
@ifset COFF
|
|
@node Type
|
|
@section @code{.type @var{int}}
|
|
|
|
@cindex COFF symbol type
|
|
@cindex symbol type, COFF
|
|
@cindex @code{type} directive
|
|
This directive, permitted only within @code{.def}/@code{.endef} pairs,
|
|
records the integer @var{int} as the type attribute of a symbol table entry.
|
|
@ifset BOUT
|
|
|
|
@samp{.type} is associated only with COFF format output; when
|
|
@code{@value{AS}} is configured for @code{b.out} output, it accepts this
|
|
directive but ignores it.
|
|
@end ifset
|
|
@end ifset
|
|
|
|
@ifset COFF
|
|
@node Val
|
|
@section @code{.val @var{addr}}
|
|
|
|
@cindex @code{val} directive
|
|
@cindex COFF value attribute
|
|
@cindex value attribute, COFF
|
|
This directive, permitted only within @code{.def}/@code{.endef} pairs,
|
|
records the address @var{addr} as the value attribute of a symbol table
|
|
entry.
|
|
@ifset BOUT
|
|
|
|
@samp{.val} is used only for COFF output; when @code{@value{AS}} is
|
|
configured for @code{b.out}, it accepts this directive but ignores it.
|
|
@end ifset
|
|
@end ifset
|
|
|
|
@node Word
|
|
@section @code{.word @var{expressions}}
|
|
|
|
@cindex @code{word} directive
|
|
This directive expects zero or more @var{expressions}, of any section,
|
|
separated by commas.
|
|
@ifclear GENERIC
|
|
@ifset W32
|
|
For each expression, @code{@value{AS}} emits a 32-bit number.
|
|
@end ifset
|
|
@ifset W16
|
|
For each expression, @code{@value{AS}} emits a 16-bit number.
|
|
@end ifset
|
|
@end ifclear
|
|
@ifset GENERIC
|
|
|
|
The size of the number emitted, and its byte order,
|
|
depend on what target computer the assembly is for.
|
|
@end ifset
|
|
|
|
@c on amd29k, i960, sparc the "special treatment to support compilers" doesn't
|
|
@c happen---32-bit addressability, period; no long/short jumps.
|
|
@ifset DIFF-TBL-KLUGE
|
|
@cindex difference tables altered
|
|
@cindex altered difference tables
|
|
@quotation
|
|
@emph{Warning: Special Treatment to support Compilers}
|
|
@end quotation
|
|
|
|
@ifset GENERIC
|
|
Machines with a 32-bit address space, but that do less than 32-bit
|
|
addressing, require the following special treatment. If the machine of
|
|
interest to you does 32-bit addressing (or doesn't require it;
|
|
@pxref{Machine Dependencies}), you can ignore this issue.
|
|
|
|
@end ifset
|
|
In order to assemble compiler output into something that works,
|
|
@code{@value{AS}} occasionlly does strange things to @samp{.word} directives.
|
|
Directives of the form @samp{.word sym1-sym2} are often emitted by
|
|
compilers as part of jump tables. Therefore, when @code{@value{AS}} assembles a
|
|
directive of the form @samp{.word sym1-sym2}, and the difference between
|
|
@code{sym1} and @code{sym2} does not fit in 16 bits, @code{@value{AS}}
|
|
creates a @dfn{secondary jump table}, immediately before the next label.
|
|
This secondary jump table is preceded by a short-jump to the
|
|
first byte after the secondary table. This short-jump prevents the flow
|
|
of control from accidentally falling into the new table. Inside the
|
|
table is a long-jump to @code{sym2}. The original @samp{.word}
|
|
contains @code{sym1} minus the address of the long-jump to
|
|
@code{sym2}.
|
|
|
|
If there were several occurrences of @samp{.word sym1-sym2} before the
|
|
secondary jump table, all of them are adjusted. If there was a
|
|
@samp{.word sym3-sym4}, that also did not fit in sixteen bits, a
|
|
long-jump to @code{sym4} is included in the secondary jump table,
|
|
and the @code{.word} directives are adjusted to contain @code{sym3}
|
|
minus the address of the long-jump to @code{sym4}; and so on, for as many
|
|
entries in the original jump table as necessary.
|
|
|
|
@ifset INTERNALS
|
|
@emph{This feature may be disabled by compiling @code{@value{AS}} with the
|
|
@samp{-DWORKING_DOT_WORD} option.} This feature is likely to confuse
|
|
assembly language programmers.
|
|
@end ifset
|
|
@end ifset
|
|
@c end DIFF-TBL-KLUGE
|
|
|
|
@node Deprecated
|
|
@section Deprecated Directives
|
|
|
|
@cindex deprecated directives
|
|
@cindex obsolescent directives
|
|
One day these directives won't work.
|
|
They are included for compatibility with older assemblers.
|
|
@table @t
|
|
@item .abort
|
|
@item .app-file
|
|
@item .line
|
|
@end table
|
|
|
|
@ifset GENERIC
|
|
@node Machine Dependencies
|
|
@chapter Machine Dependent Features
|
|
|
|
@cindex machine dependencies
|
|
The machine instruction sets are (almost by definition) different on
|
|
each machine where @code{@value{AS}} runs. Floating point representations
|
|
vary as well, and @code{@value{AS}} often supports a few additional
|
|
directives or command-line options for compatibility with other
|
|
assemblers on a particular platform. Finally, some versions of
|
|
@code{@value{AS}} support special pseudo-instructions for branch
|
|
optimization.
|
|
|
|
This chapter discusses most of these differences, though it does not
|
|
include details on any machine's instruction set. For details on that
|
|
subject, see the hardware manufacturer's manual.
|
|
|
|
@menu
|
|
@ifset VAX
|
|
* Vax-Dependent:: VAX Dependent Features
|
|
@end ifset
|
|
@ifset A29K
|
|
* AMD29K-Dependent:: AMD 29K Dependent Features
|
|
@end ifset
|
|
@ifset H8/300
|
|
* H8/300-Dependent:: Hitachi H8/300 Dependent Features
|
|
@end ifset
|
|
@ifset H8/500
|
|
* H8/500-Dependent:: Hitachi H8/500 Dependent Features
|
|
@end ifset
|
|
@ifset HPPA
|
|
* HPPA-Dependent:: HPPA Dependent Features
|
|
@end ifset
|
|
@ifset SH
|
|
* SH-Dependent:: Hitachi SH Dependent Features
|
|
@end ifset
|
|
@ifset I960
|
|
* i960-Dependent:: Intel 80960 Dependent Features
|
|
@end ifset
|
|
@ifset M680X0
|
|
* M68K-Dependent:: M680x0 Dependent Features
|
|
@end ifset
|
|
@ifset SPARC
|
|
* Sparc-Dependent:: SPARC Dependent Features
|
|
@end ifset
|
|
@ifset Z8000
|
|
* Z8000-Dependent:: Z8000 Dependent Features
|
|
@end ifset
|
|
@ifset MIPS
|
|
* MIPS-Dependent:: MIPS Dependent Features
|
|
@end ifset
|
|
@ifset I80386
|
|
* i386-Dependent:: 80386 Dependent Features
|
|
@end ifset
|
|
@end menu
|
|
|
|
@lowersections
|
|
@end ifset
|
|
|
|
@c The following major nodes are *sections* in the GENERIC version, *chapters*
|
|
@c in single-cpu versions. This is mainly achieved by @lowersections. There is a
|
|
@c peculiarity: to preserve cross-references, there must be a node called
|
|
@c "Machine Dependencies". Hence the conditional nodenames in each
|
|
@c major node below. Node defaulting in makeinfo requires adjacency of
|
|
@c node and sectioning commands; hence the repetition of @chapter BLAH
|
|
@c in both conditional blocks.
|
|
@c
|
|
@ifset VAX
|
|
@ifset GENERIC
|
|
@node Vax-Dependent
|
|
@chapter VAX Dependent Features
|
|
@cindex VAX support
|
|
|
|
@end ifset
|
|
@ifclear GENERIC
|
|
@node Machine Dependencies
|
|
@chapter VAX Dependent Features
|
|
@cindex VAX support
|
|
|
|
@end ifclear
|
|
|
|
@menu
|
|
* Vax-Opts:: VAX Command-Line Options
|
|
* VAX-float:: VAX Floating Point
|
|
* VAX-directives:: Vax Machine Directives
|
|
* VAX-opcodes:: VAX Opcodes
|
|
* VAX-branch:: VAX Branch Improvement
|
|
* VAX-operands:: VAX Operands
|
|
* VAX-no:: Not Supported on VAX
|
|
@end menu
|
|
|
|
|
|
@node Vax-Opts
|
|
@section VAX Command-Line Options
|
|
|
|
@cindex command-line options ignored, VAX
|
|
@cindex VAX command-line options ignored
|
|
The Vax version of @code{@value{AS}} accepts any of the following options,
|
|
gives a warning message that the option was ignored and proceeds.
|
|
These options are for compatibility with scripts designed for other
|
|
people's assemblers.
|
|
|
|
@table @code
|
|
@item @code{-D} (Debug)
|
|
@itemx @code{-S} (Symbol Table)
|
|
@itemx @code{-T} (Token Trace)
|
|
@cindex @code{-D}, ignored on VAX
|
|
@cindex @code{-S}, ignored on VAX
|
|
@cindex @code{-T}, ignored on VAX
|
|
These are obsolete options used to debug old assemblers.
|
|
|
|
@item @code{-d} (Displacement size for JUMPs)
|
|
@cindex @code{-d}, VAX option
|
|
This option expects a number following the @samp{-d}. Like options
|
|
that expect filenames, the number may immediately follow the
|
|
@samp{-d} (old standard) or constitute the whole of the command line
|
|
argument that follows @samp{-d} (@sc{gnu} standard).
|
|
|
|
@item @code{-V} (Virtualize Interpass Temporary File)
|
|
@cindex @code{-V}, redundant on VAX
|
|
Some other assemblers use a temporary file. This option
|
|
commanded them to keep the information in active memory rather
|
|
than in a disk file. @code{@value{AS}} always does this, so this
|
|
option is redundant.
|
|
|
|
@item @code{-J} (JUMPify Longer Branches)
|
|
@cindex @code{-J}, ignored on VAX
|
|
Many 32-bit computers permit a variety of branch instructions
|
|
to do the same job. Some of these instructions are short (and
|
|
fast) but have a limited range; others are long (and slow) but
|
|
can branch anywhere in virtual memory. Often there are 3
|
|
flavors of branch: short, medium and long. Some other
|
|
assemblers would emit short and medium branches, unless told by
|
|
this option to emit short and long branches.
|
|
|
|
@item @code{-t} (Temporary File Directory)
|
|
@cindex @code{-t}, ignored on VAX
|
|
Some other assemblers may use a temporary file, and this option
|
|
takes a filename being the directory to site the temporary
|
|
file. Since @code{@value{AS}} does not use a temporary disk file, this
|
|
option makes no difference. @samp{-t} needs exactly one
|
|
filename.
|
|
@end table
|
|
|
|
@cindex VMS (VAX) options
|
|
@cindex options for VAX/VMS
|
|
@cindex VAX/VMS options
|
|
@cindex @code{-h} option, VAX/VMS
|
|
@cindex @code{-+} option, VAX/VMS
|
|
@cindex Vax-11 C compatibility
|
|
@cindex symbols with lowercase, VAX/VMS
|
|
@c FIXME! look into "I think" below, correct if needed, delete.
|
|
The Vax version of the assembler accepts two options when
|
|
compiled for VMS. They are @samp{-h}, and @samp{-+}. The
|
|
@samp{-h} option prevents @code{@value{AS}} from modifying the
|
|
symbol-table entries for symbols that contain lowercase
|
|
characters (I think). The @samp{-+} option causes @code{@value{AS}} to
|
|
print warning messages if the FILENAME part of the object file,
|
|
or any symbol name is larger than 31 characters. The @samp{-+}
|
|
option also inserts some code following the @samp{_main}
|
|
symbol so that the object file is compatible with Vax-11
|
|
"C".
|
|
|
|
@node VAX-float
|
|
@section VAX Floating Point
|
|
|
|
@cindex VAX floating point
|
|
@cindex floating point, VAX
|
|
Conversion of flonums to floating point is correct, and
|
|
compatible with previous assemblers. Rounding is
|
|
towards zero if the remainder is exactly half the least significant bit.
|
|
|
|
@code{D}, @code{F}, @code{G} and @code{H} floating point formats
|
|
are understood.
|
|
|
|
Immediate floating literals (@emph{e.g.} @samp{S`$6.9})
|
|
are rendered correctly. Again, rounding is towards zero in the
|
|
boundary case.
|
|
|
|
@cindex @code{float} directive, VAX
|
|
@cindex @code{double} directive, VAX
|
|
The @code{.float} directive produces @code{f} format numbers.
|
|
The @code{.double} directive produces @code{d} format numbers.
|
|
|
|
@node VAX-directives
|
|
@section Vax Machine Directives
|
|
|
|
@cindex machine directives, VAX
|
|
@cindex VAX machine directives
|
|
The Vax version of the assembler supports four directives for
|
|
generating Vax floating point constants. They are described in the
|
|
table below.
|
|
|
|
@cindex wide floating point directives, VAX
|
|
@table @code
|
|
@item .dfloat
|
|
@cindex @code{dfloat} directive, VAX
|
|
This expects zero or more flonums, separated by commas, and
|
|
assembles Vax @code{d} format 64-bit floating point constants.
|
|
|
|
@item .ffloat
|
|
@cindex @code{ffloat} directive, VAX
|
|
This expects zero or more flonums, separated by commas, and
|
|
assembles Vax @code{f} format 32-bit floating point constants.
|
|
|
|
@item .gfloat
|
|
@cindex @code{gfloat} directive, VAX
|
|
This expects zero or more flonums, separated by commas, and
|
|
assembles Vax @code{g} format 64-bit floating point constants.
|
|
|
|
@item .hfloat
|
|
@cindex @code{hfloat} directive, VAX
|
|
This expects zero or more flonums, separated by commas, and
|
|
assembles Vax @code{h} format 128-bit floating point constants.
|
|
|
|
@end table
|
|
|
|
@node VAX-opcodes
|
|
@section VAX Opcodes
|
|
|
|
@cindex VAX opcode mnemonics
|
|
@cindex opcode mnemonics, VAX
|
|
@cindex mnemonics for opcodes, VAX
|
|
All DEC mnemonics are supported. Beware that @code{case@dots{}}
|
|
instructions have exactly 3 operands. The dispatch table that
|
|
follows the @code{case@dots{}} instruction should be made with
|
|
@code{.word} statements. This is compatible with all unix
|
|
assemblers we know of.
|
|
|
|
@node VAX-branch
|
|
@section VAX Branch Improvement
|
|
|
|
@cindex VAX branch improvement
|
|
@cindex branch improvement, VAX
|
|
@cindex pseudo-ops for branch, VAX
|
|
Certain pseudo opcodes are permitted. They are for branch
|
|
instructions. They expand to the shortest branch instruction that
|
|
reaches the target. Generally these mnemonics are made by
|
|
substituting @samp{j} for @samp{b} at the start of a DEC mnemonic.
|
|
This feature is included both for compatibility and to help
|
|
compilers. If you do not need this feature, avoid these
|
|
opcodes. Here are the mnemonics, and the code they can expand into.
|
|
|
|
@table @code
|
|
@item jbsb
|
|
@samp{Jsb} is already an instruction mnemonic, so we chose @samp{jbsb}.
|
|
@table @asis
|
|
@item (byte displacement)
|
|
@kbd{bsbb @dots{}}
|
|
@item (word displacement)
|
|
@kbd{bsbw @dots{}}
|
|
@item (long displacement)
|
|
@kbd{jsb @dots{}}
|
|
@end table
|
|
@item jbr
|
|
@itemx jr
|
|
Unconditional branch.
|
|
@table @asis
|
|
@item (byte displacement)
|
|
@kbd{brb @dots{}}
|
|
@item (word displacement)
|
|
@kbd{brw @dots{}}
|
|
@item (long displacement)
|
|
@kbd{jmp @dots{}}
|
|
@end table
|
|
@item j@var{COND}
|
|
@var{COND} may be any one of the conditional branches
|
|
@code{neq}, @code{nequ}, @code{eql}, @code{eqlu}, @code{gtr},
|
|
@code{geq}, @code{lss}, @code{gtru}, @code{lequ}, @code{vc}, @code{vs},
|
|
@code{gequ}, @code{cc}, @code{lssu}, @code{cs}.
|
|
@var{COND} may also be one of the bit tests
|
|
@code{bs}, @code{bc}, @code{bss}, @code{bcs}, @code{bsc}, @code{bcc},
|
|
@code{bssi}, @code{bcci}, @code{lbs}, @code{lbc}.
|
|
@var{NOTCOND} is the opposite condition to @var{COND}.
|
|
@table @asis
|
|
@item (byte displacement)
|
|
@kbd{b@var{COND} @dots{}}
|
|
@item (word displacement)
|
|
@kbd{b@var{NOTCOND} foo ; brw @dots{} ; foo:}
|
|
@item (long displacement)
|
|
@kbd{b@var{NOTCOND} foo ; jmp @dots{} ; foo:}
|
|
@end table
|
|
@item jacb@var{X}
|
|
@var{X} may be one of @code{b d f g h l w}.
|
|
@table @asis
|
|
@item (word displacement)
|
|
@kbd{@var{OPCODE} @dots{}}
|
|
@item (long displacement)
|
|
@example
|
|
@var{OPCODE} @dots{}, foo ;
|
|
brb bar ;
|
|
foo: jmp @dots{} ;
|
|
bar:
|
|
@end example
|
|
@end table
|
|
@item jaob@var{YYY}
|
|
@var{YYY} may be one of @code{lss leq}.
|
|
@item jsob@var{ZZZ}
|
|
@var{ZZZ} may be one of @code{geq gtr}.
|
|
@table @asis
|
|
@item (byte displacement)
|
|
@kbd{@var{OPCODE} @dots{}}
|
|
@item (word displacement)
|
|
@example
|
|
@var{OPCODE} @dots{}, foo ;
|
|
brb bar ;
|
|
foo: brw @var{destination} ;
|
|
bar:
|
|
@end example
|
|
@item (long displacement)
|
|
@example
|
|
@var{OPCODE} @dots{}, foo ;
|
|
brb bar ;
|
|
foo: jmp @var{destination} ;
|
|
bar:
|
|
@end example
|
|
@end table
|
|
@item aobleq
|
|
@itemx aoblss
|
|
@itemx sobgeq
|
|
@itemx sobgtr
|
|
@table @asis
|
|
@item (byte displacement)
|
|
@kbd{@var{OPCODE} @dots{}}
|
|
@item (word displacement)
|
|
@example
|
|
@var{OPCODE} @dots{}, foo ;
|
|
brb bar ;
|
|
foo: brw @var{destination} ;
|
|
bar:
|
|
@end example
|
|
@item (long displacement)
|
|
@example
|
|
@var{OPCODE} @dots{}, foo ;
|
|
brb bar ;
|
|
foo: jmp @var{destination} ;
|
|
bar:
|
|
@end example
|
|
@end table
|
|
@end table
|
|
|
|
@node VAX-operands
|
|
@section VAX Operands
|
|
|
|
@cindex VAX operand notation
|
|
@cindex operand notation, VAX
|
|
@cindex immediate character, VAX
|
|
@cindex VAX immediate character
|
|
The immediate character is @samp{$} for Unix compatibility, not
|
|
@samp{#} as DEC writes it.
|
|
|
|
@cindex indirect character, VAX
|
|
@cindex VAX indirect character
|
|
The indirect character is @samp{*} for Unix compatibility, not
|
|
@samp{@@} as DEC writes it.
|
|
|
|
@cindex displacement sizing character, VAX
|
|
@cindex VAX displacement sizing character
|
|
The displacement sizing character is @samp{`} (an accent grave) for
|
|
Unix compatibility, not @samp{^} as DEC writes it. The letter
|
|
preceding @samp{`} may have either case. @samp{G} is not
|
|
understood, but all other letters (@code{b i l s w}) are understood.
|
|
|
|
@cindex register names, VAX
|
|
@cindex VAX register names
|
|
Register names understood are @code{r0 r1 r2 @dots{} r15 ap fp sp
|
|
pc}. Upper and lower case letters are equivalent.
|
|
|
|
For instance
|
|
@smallexample
|
|
tstb *w`$4(r5)
|
|
@end smallexample
|
|
|
|
Any expression is permitted in an operand. Operands are comma
|
|
separated.
|
|
|
|
@c There is some bug to do with recognizing expressions
|
|
@c in operands, but I forget what it is. It is
|
|
@c a syntax clash because () is used as an address mode
|
|
@c and to encapsulate sub-expressions.
|
|
|
|
@node VAX-no
|
|
@section Not Supported on VAX
|
|
|
|
@cindex VAX bitfields not supported
|
|
@cindex bitfields, not supported on VAX
|
|
Vax bit fields can not be assembled with @code{@value{AS}}. Someone
|
|
can add the required code if they really need it.
|
|
|
|
@end ifset
|
|
@ifset A29K
|
|
@ifset GENERIC
|
|
@page
|
|
@node AMD29K-Dependent
|
|
@chapter AMD 29K Dependent Features
|
|
@end ifset
|
|
@ifclear GENERIC
|
|
@node Machine Dependencies
|
|
@chapter AMD 29K Dependent Features
|
|
@end ifclear
|
|
|
|
@cindex AMD 29K support
|
|
@cindex 29K support
|
|
@menu
|
|
* AMD29K Options:: Options
|
|
* AMD29K Syntax:: Syntax
|
|
* AMD29K Floating Point:: Floating Point
|
|
* AMD29K Directives:: AMD 29K Machine Directives
|
|
* AMD29K Opcodes:: Opcodes
|
|
@end menu
|
|
|
|
@node AMD29K Options
|
|
@section Options
|
|
@cindex AMD 29K options (none)
|
|
@cindex options for AMD29K (none)
|
|
@code{@value{AS}} has no additional command-line options for the AMD
|
|
29K family.
|
|
|
|
@node AMD29K Syntax
|
|
@section Syntax
|
|
@menu
|
|
* AMD29K-Chars:: Special Characters
|
|
* AMD29K-Regs:: Register Names
|
|
@end menu
|
|
|
|
@node AMD29K-Chars
|
|
@subsection Special Characters
|
|
|
|
@cindex line comment character, AMD 29K
|
|
@cindex AMD 29K line comment character
|
|
@samp{;} is the line comment character.
|
|
|
|
@cindex line separator, AMD 29K
|
|
@cindex AMD 29K line separator
|
|
@cindex statement separator, AMD 29K
|
|
@cindex AMD 29K statement separator
|
|
@samp{@@} can be used instead of a newline to separate statements.
|
|
|
|
@cindex identifiers, AMD 29K
|
|
@cindex AMD 29K identifiers
|
|
The character @samp{?} is permitted in identifiers (but may not begin
|
|
an identifier).
|
|
|
|
@node AMD29K-Regs
|
|
@subsection Register Names
|
|
|
|
@cindex AMD 29K register names
|
|
@cindex register names, AMD 29K
|
|
General-purpose registers are represented by predefined symbols of the
|
|
form @samp{GR@var{nnn}} (for global registers) or @samp{LR@var{nnn}}
|
|
(for local registers), where @var{nnn} represents a number between
|
|
@code{0} and @code{127}, written with no leading zeros. The leading
|
|
letters may be in either upper or lower case; for example, @samp{gr13}
|
|
and @samp{LR7} are both valid register names.
|
|
|
|
You may also refer to general-purpose registers by specifying the
|
|
register number as the result of an expression (prefixed with @samp{%%}
|
|
to flag the expression as a register number):
|
|
@smallexample
|
|
%%@var{expression}
|
|
@end smallexample
|
|
@noindent
|
|
---where @var{expression} must be an absolute expression evaluating to a
|
|
number between @code{0} and @code{255}. The range [0, 127] refers to
|
|
global registers, and the range [128, 255] to local registers.
|
|
|
|
@cindex special purpose registers, AMD 29K
|
|
@cindex AMD 29K special purpose registers
|
|
@cindex protected registers, AMD 29K
|
|
@cindex AMD 29K protected registers
|
|
In addition, @code{@value{AS}} understands the following protected
|
|
special-purpose register names for the AMD 29K family:
|
|
|
|
@smallexample
|
|
vab chd pc0
|
|
ops chc pc1
|
|
cps rbp pc2
|
|
cfg tmc mmu
|
|
cha tmr lru
|
|
@end smallexample
|
|
|
|
These unprotected special-purpose register names are also recognized:
|
|
@smallexample
|
|
ipc alu fpe
|
|
ipa bp inte
|
|
ipb fc fps
|
|
q cr exop
|
|
@end smallexample
|
|
|
|
@node AMD29K Floating Point
|
|
@section Floating Point
|
|
|
|
@cindex floating point, AMD 29K (@sc{ieee})
|
|
@cindex AMD 29K floating point (@sc{ieee})
|
|
The AMD 29K family uses @sc{ieee} floating-point numbers.
|
|
|
|
@node AMD29K Directives
|
|
@section AMD 29K Machine Directives
|
|
|
|
@cindex machine directives, AMD 29K
|
|
@cindex AMD 29K machine directives
|
|
@table @code
|
|
@item .block @var{size} , @var{fill}
|
|
@cindex @code{block} directive, AMD 29K
|
|
This directive emits @var{size} bytes, each of value @var{fill}. Both
|
|
@var{size} and @var{fill} are absolute expressions. If the comma
|
|
and @var{fill} are omitted, @var{fill} is assumed to be zero.
|
|
|
|
In other versions of the @sc{gnu} assembler, this directive is called
|
|
@samp{.space}.
|
|
@end table
|
|
|
|
@table @code
|
|
@item .cputype
|
|
@cindex @code{cputype} directive, AMD 29K
|
|
This directive is ignored; it is accepted for compatibility with other
|
|
AMD 29K assemblers.
|
|
|
|
@item .file
|
|
@cindex @code{file} directive, AMD 29K
|
|
This directive is ignored; it is accepted for compatibility with other
|
|
AMD 29K assemblers.
|
|
|
|
@quotation
|
|
@emph{Warning:} in other versions of the @sc{gnu} assembler, @code{.file} is
|
|
used for the directive called @code{.app-file} in the AMD 29K support.
|
|
@end quotation
|
|
|
|
@item .line
|
|
@cindex @code{line} directive, AMD 29K
|
|
This directive is ignored; it is accepted for compatibility with other
|
|
AMD 29K assemblers.
|
|
|
|
@ignore
|
|
@c since we're ignoring .lsym...
|
|
@item .reg @var{symbol}, @var{expression}
|
|
@cindex @code{reg} directive, AMD 29K
|
|
@code{.reg} has the same effect as @code{.lsym}; @pxref{Lsym,,@code{.lsym}}.
|
|
@end ignore
|
|
|
|
@item .sect
|
|
@cindex @code{sect} directive, AMD 29K
|
|
This directive is ignored; it is accepted for compatibility with other
|
|
AMD 29K assemblers.
|
|
|
|
@item .use @var{section name}
|
|
@cindex @code{use} directive, AMD 29K
|
|
Establishes the section and subsection for the following code;
|
|
@var{section name} may be one of @code{.text}, @code{.data},
|
|
@code{.data1}, or @code{.lit}. With one of the first three @var{section
|
|
name} options, @samp{.use} is equivalent to the machine directive
|
|
@var{section name}; the remaining case, @samp{.use .lit}, is the same as
|
|
@samp{.data 200}.
|
|
@end table
|
|
|
|
@node AMD29K Opcodes
|
|
@section Opcodes
|
|
|
|
@cindex AMD 29K opcodes
|
|
@cindex opcodes for AMD 29K
|
|
@code{@value{AS}} implements all the standard AMD 29K opcodes. No
|
|
additional pseudo-instructions are needed on this family.
|
|
|
|
For information on the 29K machine instruction set, see @cite{Am29000
|
|
User's Manual}, Advanced Micro Devices, Inc.
|
|
|
|
@end ifset
|
|
@ifset Hitachi-all
|
|
@ifclear GENERIC
|
|
@node Machine Dependencies
|
|
@chapter Machine Dependent Features
|
|
|
|
The machine instruction sets are different on each Hitachi chip family,
|
|
and there are also some syntax differences among the families. This
|
|
chapter describes the specific @code{@value{AS}} features for each
|
|
family.
|
|
|
|
@menu
|
|
* H8/300-Dependent:: Hitachi H8/300 Dependent Features
|
|
* H8/500-Dependent:: Hitachi H8/500 Dependent Features
|
|
* SH-Dependent:: Hitachi SH Dependent Features
|
|
@end menu
|
|
@lowersections
|
|
@end ifclear
|
|
@end ifset
|
|
|
|
@ifset H8/300
|
|
@ifset GENERIC
|
|
@page
|
|
@end ifset
|
|
@node H8/300-Dependent
|
|
@chapter H8/300 Dependent Features
|
|
|
|
@cindex H8/300 support
|
|
@menu
|
|
* H8/300 Options:: Options
|
|
* H8/300 Syntax:: Syntax
|
|
* H8/300 Floating Point:: Floating Point
|
|
* H8/300 Directives:: H8/300 Machine Directives
|
|
* H8/300 Opcodes:: Opcodes
|
|
@end menu
|
|
|
|
@node H8/300 Options
|
|
@section Options
|
|
|
|
@cindex H8/300 options (none)
|
|
@cindex options, H8/300 (none)
|
|
@code{@value{AS}} has no additional command-line options for the Hitachi
|
|
H8/300 family.
|
|
|
|
@node H8/300 Syntax
|
|
@section Syntax
|
|
@menu
|
|
* H8/300-Chars:: Special Characters
|
|
* H8/300-Regs:: Register Names
|
|
* H8/300-Addressing:: Addressing Modes
|
|
@end menu
|
|
|
|
@node H8/300-Chars
|
|
@subsection Special Characters
|
|
|
|
@cindex line comment character, H8/300
|
|
@cindex H8/300 line comment character
|
|
@samp{;} is the line comment character.
|
|
|
|
@cindex line separator, H8/300
|
|
@cindex statement separator, H8/300
|
|
@cindex H8/300 line separator
|
|
@samp{$} can be used instead of a newline to separate statements.
|
|
Therefore @emph{you may not use @samp{$} in symbol names} on the H8/300.
|
|
|
|
@node H8/300-Regs
|
|
@subsection Register Names
|
|
|
|
@cindex H8/300 registers
|
|
@cindex register names, H8/300
|
|
You can use predefined symbols of the form @samp{r@var{n}h} and
|
|
@samp{r@var{n}l} to refer to the H8/300 registers as sixteen 8-bit
|
|
general-purpose registers. @var{n} is a digit from @samp{0} to
|
|
@samp{7}); for instance, both @samp{r0h} and @samp{r7l} are valid
|
|
register names.
|
|
|
|
You can also use the eight predefined symbols @samp{r@var{n}} to refer
|
|
to the H8/300 registers as 16-bit registers (you must use this form for
|
|
addressing).
|
|
|
|
On the H8/300H, you can also use the eight predefined symbols
|
|
@samp{er@var{n}} (@samp{er0} @dots{} @samp{er7}) to refer to the 32-bit
|
|
general purpose registers.
|
|
|
|
The two control registers are called @code{pc} (program counter; a
|
|
16-bit register, except on the H8/300H where it is 24 bits) and
|
|
@code{ccr} (condition code register; an 8-bit register). @code{r7} is
|
|
used as the stack pointer, and can also be called @code{sp}.
|
|
|
|
@node H8/300-Addressing
|
|
@subsection Addressing Modes
|
|
|
|
@cindex addressing modes, H8/300
|
|
@cindex H8/300 addressing modes
|
|
@value{AS} understands the following addressing modes for the H8/300:
|
|
@table @code
|
|
@item r@var{n}
|
|
Register direct
|
|
|
|
@item @@r@var{n}
|
|
Register indirect
|
|
|
|
@item @@(@var{d}, r@var{n})
|
|
@itemx @@(@var{d}:16, r@var{n})
|
|
@itemx @@(@var{d}:24, r@var{n})
|
|
Register indirect: 16-bit or 24-bit displacement @var{d} from register
|
|
@var{n}. (24-bit displacements are only meaningful on the H8/300H.)
|
|
|
|
@item @@r@var{n}+
|
|
Register indirect with post-increment
|
|
|
|
@item @@-r@var{n}
|
|
Register indirect with pre-decrement
|
|
|
|
@item @code{@@}@var{aa}
|
|
@itemx @code{@@}@var{aa}:8
|
|
@itemx @code{@@}@var{aa}:16
|
|
@itemx @code{@@}@var{aa}:24
|
|
Absolute address @code{aa}. (The address size @samp{:24} only makes
|
|
sense on the H8/300H.)
|
|
|
|
@item #@var{xx}
|
|
@itemx #@var{xx}:8
|
|
@itemx #@var{xx}:16
|
|
@itemx #@var{xx}:32
|
|
Immediate data @var{xx}. You may specify the @samp{:8}, @samp{:16}, or
|
|
@samp{:32} for clarity, if you wish; but @code{@value{AS}} neither
|
|
requires this nor uses it---the data size required is taken from
|
|
context.
|
|
|
|
@item @code{@@}@code{@@}@var{aa}
|
|
@itemx @code{@@}@code{@@}@var{aa}:8
|
|
Memory indirect. You may specify the @samp{:8} for clarity, if you
|
|
wish; but @code{@value{AS}} neither requires this nor uses it.
|
|
@end table
|
|
|
|
@node H8/300 Floating Point
|
|
@section Floating Point
|
|
|
|
@cindex floating point, H8/300 (@sc{ieee})
|
|
@cindex H8/300 floating point (@sc{ieee})
|
|
The H8/300 family has no hardware floating point, but the @code{.float}
|
|
directive generates @sc{ieee} floating-point numbers for compatibility
|
|
with other development tools.
|
|
|
|
@page
|
|
@node H8/300 Directives
|
|
@section H8/300 Machine Directives
|
|
|
|
@cindex H8/300 machine directives (none)
|
|
@cindex machine directives, H8/300 (none)
|
|
@cindex @code{word} directive, H8/300
|
|
@cindex @code{int} directive, H8/300
|
|
@code{@value{AS}} has only one machine-dependent directive for the
|
|
H8/300:
|
|
|
|
@table @code
|
|
@cindex H8/300H, assembling for
|
|
@item .h8300h
|
|
Recognize and emit additional instructions for the H8/300H variant, and
|
|
also make @code{.int} emit 32-bit numbers rather than the usual (16-bit)
|
|
for the H8/300 family.
|
|
@end table
|
|
|
|
On the H8/300 family (including the H8/300H) @samp{.word} directives
|
|
generate 16-bit numbers.
|
|
|
|
@node H8/300 Opcodes
|
|
@section Opcodes
|
|
|
|
@cindex H8/300 opcode summary
|
|
@cindex opcode summary, H8/300
|
|
@cindex mnemonics, H8/300
|
|
@cindex instruction summary, H8/300
|
|
For detailed information on the H8/300 machine instruction set, see
|
|
@cite{H8/300 Series Programming Manual} (Hitachi ADE--602--025). For
|
|
information specific to the H8/300H, see @cite{H8/300H Series
|
|
Programming Manual} (Hitachi).
|
|
|
|
@code{@value{AS}} implements all the standard H8/300 opcodes. No additional
|
|
pseudo-instructions are needed on this family.
|
|
|
|
@ifset SMALL
|
|
@c this table, due to the multi-col faking and hardcoded order, looks silly
|
|
@c except in smallbook. See comments below "@set SMALL" near top of this file.
|
|
|
|
The following table summarizes the H8/300 opcodes, and their arguments.
|
|
Entries marked @samp{*} are opcodes used only on the H8/300H.
|
|
|
|
@smallexample
|
|
@c Using @group seems to use the normal baselineskip, not the smallexample
|
|
@c baselineskip; looks approx doublespaced.
|
|
@i{Legend:}
|
|
Rs @r{source register}
|
|
Rd @r{destination register}
|
|
abs @r{absolute address}
|
|
imm @r{immediate data}
|
|
disp:N @r{N-bit displacement from a register}
|
|
pcrel:N @r{N-bit displacement relative to program counter}
|
|
|
|
add.b #imm,rd * andc #imm,ccr
|
|
add.b rs,rd band #imm,rd
|
|
add.w rs,rd band #imm,@@rd
|
|
* add.w #imm,rd band #imm,@@abs:8
|
|
* add.l rs,rd bra pcrel:8
|
|
* add.l #imm,rd * bra pcrel:16
|
|
adds #imm,rd bt pcrel:8
|
|
addx #imm,rd * bt pcrel:16
|
|
addx rs,rd brn pcrel:8
|
|
and.b #imm,rd * brn pcrel:16
|
|
and.b rs,rd bf pcrel:8
|
|
* and.w rs,rd * bf pcrel:16
|
|
* and.w #imm,rd bhi pcrel:8
|
|
* and.l #imm,rd * bhi pcrel:16
|
|
* and.l rs,rd bls pcrel:8
|
|
@page
|
|
* bls pcrel:16 bld #imm,rd
|
|
bcc pcrel:8 bld #imm,@@rd
|
|
* bcc pcrel:16 bld #imm,@@abs:8
|
|
bhs pcrel:8 bnot #imm,rd
|
|
* bhs pcrel:16 bnot #imm,@@rd
|
|
bcs pcrel:8 bnot #imm,@@abs:8
|
|
* bcs pcrel:16 bnot rs,rd
|
|
blo pcrel:8 bnot rs,@@rd
|
|
* blo pcrel:16 bnot rs,@@abs:8
|
|
bne pcrel:8 bor #imm,rd
|
|
* bne pcrel:16 bor #imm,@@rd
|
|
beq pcrel:8 bor #imm,@@abs:8
|
|
* beq pcrel:16 bset #imm,rd
|
|
bvc pcrel:8 bset #imm,@@rd
|
|
* bvc pcrel:16 bset #imm,@@abs:8
|
|
bvs pcrel:8 bset rs,rd
|
|
* bvs pcrel:16 bset rs,@@rd
|
|
bpl pcrel:8 bset rs,@@abs:8
|
|
* bpl pcrel:16 bsr pcrel:8
|
|
bmi pcrel:8 bsr pcrel:16
|
|
* bmi pcrel:16 bst #imm,rd
|
|
bge pcrel:8 bst #imm,@@rd
|
|
* bge pcrel:16 bst #imm,@@abs:8
|
|
blt pcrel:8 btst #imm,rd
|
|
* blt pcrel:16 btst #imm,@@rd
|
|
bgt pcrel:8 btst #imm,@@abs:8
|
|
* bgt pcrel:16 btst rs,rd
|
|
ble pcrel:8 btst rs,@@rd
|
|
* ble pcrel:16 btst rs,@@abs:8
|
|
bclr #imm,rd bxor #imm,rd
|
|
bclr #imm,@@rd bxor #imm,@@rd
|
|
bclr #imm,@@abs:8 bxor #imm,@@abs:8
|
|
bclr rs,rd cmp.b #imm,rd
|
|
bclr rs,@@rd cmp.b rs,rd
|
|
bclr rs,@@abs:8 cmp.w rs,rd
|
|
biand #imm,rd cmp.w rs,rd
|
|
biand #imm,@@rd * cmp.w #imm,rd
|
|
biand #imm,@@abs:8 * cmp.l #imm,rd
|
|
bild #imm,rd * cmp.l rs,rd
|
|
bild #imm,@@rd daa rs
|
|
bild #imm,@@abs:8 das rs
|
|
bior #imm,rd dec.b rs
|
|
bior #imm,@@rd * dec.w #imm,rd
|
|
bior #imm,@@abs:8 * dec.l #imm,rd
|
|
bist #imm,rd divxu.b rs,rd
|
|
bist #imm,@@rd * divxu.w rs,rd
|
|
bist #imm,@@abs:8 * divxs.b rs,rd
|
|
bixor #imm,rd * divxs.w rs,rd
|
|
bixor #imm,@@rd eepmov
|
|
bixor #imm,@@abs:8 * eepmovw
|
|
@page
|
|
* exts.w rd mov.w rs,@@abs:16
|
|
* exts.l rd * mov.l #imm,rd
|
|
* extu.w rd * mov.l rs,rd
|
|
* extu.l rd * mov.l @@rs,rd
|
|
inc rs * mov.l @@(disp:16,rs),rd
|
|
* inc.w #imm,rd * mov.l @@(disp:24,rs),rd
|
|
* inc.l #imm,rd * mov.l @@rs+,rd
|
|
jmp @@rs * mov.l @@abs:16,rd
|
|
jmp abs * mov.l @@abs:24,rd
|
|
jmp @@@@abs:8 * mov.l rs,@@rd
|
|
jsr @@rs * mov.l rs,@@(disp:16,rd)
|
|
jsr abs * mov.l rs,@@(disp:24,rd)
|
|
jsr @@@@abs:8 * mov.l rs,@@-rd
|
|
ldc #imm,ccr * mov.l rs,@@abs:16
|
|
ldc rs,ccr * mov.l rs,@@abs:24
|
|
* ldc @@abs:16,ccr movfpe @@abs:16,rd
|
|
* ldc @@abs:24,ccr movtpe rs,@@abs:16
|
|
* ldc @@(disp:16,rs),ccr mulxu.b rs,rd
|
|
* ldc @@(disp:24,rs),ccr * mulxu.w rs,rd
|
|
* ldc @@rs+,ccr * mulxs.b rs,rd
|
|
* ldc @@rs,ccr * mulxs.w rs,rd
|
|
* mov.b @@(disp:24,rs),rd neg.b rs
|
|
* mov.b rs,@@(disp:24,rd) * neg.w rs
|
|
mov.b @@abs:16,rd * neg.l rs
|
|
mov.b rs,rd nop
|
|
mov.b @@abs:8,rd not.b rs
|
|
mov.b rs,@@abs:8 * not.w rs
|
|
mov.b rs,rd * not.l rs
|
|
mov.b #imm,rd or.b #imm,rd
|
|
mov.b @@rs,rd or.b rs,rd
|
|
mov.b @@(disp:16,rs),rd * or.w #imm,rd
|
|
mov.b @@rs+,rd * or.w rs,rd
|
|
mov.b @@abs:8,rd * or.l #imm,rd
|
|
mov.b rs,@@rd * or.l rs,rd
|
|
mov.b rs,@@(disp:16,rd) orc #imm,ccr
|
|
mov.b rs,@@-rd pop.w rs
|
|
mov.b rs,@@abs:8 * pop.l rs
|
|
mov.w rs,@@rd push.w rs
|
|
* mov.w @@(disp:24,rs),rd * push.l rs
|
|
* mov.w rs,@@(disp:24,rd) rotl.b rs
|
|
* mov.w @@abs:24,rd * rotl.w rs
|
|
* mov.w rs,@@abs:24 * rotl.l rs
|
|
mov.w rs,rd rotr.b rs
|
|
mov.w #imm,rd * rotr.w rs
|
|
mov.w @@rs,rd * rotr.l rs
|
|
mov.w @@(disp:16,rs),rd rotxl.b rs
|
|
mov.w @@rs+,rd * rotxl.w rs
|
|
mov.w @@abs:16,rd * rotxl.l rs
|
|
mov.w rs,@@(disp:16,rd) rotxr.b rs
|
|
mov.w rs,@@-rd * rotxr.w rs
|
|
@page
|
|
* rotxr.l rs * stc ccr,@@(disp:24,rd)
|
|
bpt * stc ccr,@@-rd
|
|
rte * stc ccr,@@abs:16
|
|
rts * stc ccr,@@abs:24
|
|
shal.b rs sub.b rs,rd
|
|
* shal.w rs sub.w rs,rd
|
|
* shal.l rs * sub.w #imm,rd
|
|
shar.b rs * sub.l rs,rd
|
|
* shar.w rs * sub.l #imm,rd
|
|
* shar.l rs subs #imm,rd
|
|
shll.b rs subx #imm,rd
|
|
* shll.w rs subx rs,rd
|
|
* shll.l rs * trapa #imm
|
|
shlr.b rs xor #imm,rd
|
|
* shlr.w rs xor rs,rd
|
|
* shlr.l rs * xor.w #imm,rd
|
|
sleep * xor.w rs,rd
|
|
stc ccr,rd * xor.l #imm,rd
|
|
* stc ccr,@@rs * xor.l rs,rd
|
|
* stc ccr,@@(disp:16,rd) xorc #imm,ccr
|
|
@end smallexample
|
|
@end ifset
|
|
|
|
@cindex size suffixes, H8/300
|
|
@cindex H8/300 size suffixes
|
|
Four H8/300 instructions (@code{add}, @code{cmp}, @code{mov},
|
|
@code{sub}) are defined with variants using the suffixes @samp{.b},
|
|
@samp{.w}, and @samp{.l} to specify the size of a memory operand.
|
|
@code{@value{AS}} supports these suffixes, but does not require them;
|
|
since one of the operands is always a register, @code{@value{AS}} can
|
|
deduce the correct size.
|
|
|
|
For example, since @code{r0} refers to a 16-bit register,
|
|
@example
|
|
mov r0,@@foo
|
|
@exdent is equivalent to
|
|
mov.w r0,@@foo
|
|
@end example
|
|
|
|
If you use the size suffixes, @code{@value{AS}} issues a warning when
|
|
the suffix and the register size do not match.
|
|
@end ifset
|
|
|
|
@ifset H8/500
|
|
@page
|
|
@node H8/500-Dependent
|
|
@chapter H8/500 Dependent Features
|
|
|
|
@cindex H8/500 support
|
|
@menu
|
|
* H8/500 Options:: Options
|
|
* H8/500 Syntax:: Syntax
|
|
* H8/500 Floating Point:: Floating Point
|
|
* H8/500 Directives:: H8/500 Machine Directives
|
|
* H8/500 Opcodes:: Opcodes
|
|
@end menu
|
|
|
|
@node H8/500 Options
|
|
@section Options
|
|
|
|
@cindex H8/500 options (none)
|
|
@cindex options, H8/500 (none)
|
|
@code{@value{AS}} has no additional command-line options for the Hitachi
|
|
H8/500 family.
|
|
|
|
@node H8/500 Syntax
|
|
@section Syntax
|
|
|
|
@menu
|
|
* H8/500-Chars:: Special Characters
|
|
* H8/500-Regs:: Register Names
|
|
* H8/500-Addressing:: Addressing Modes
|
|
@end menu
|
|
|
|
@node H8/500-Chars
|
|
@subsection Special Characters
|
|
|
|
@cindex line comment character, H8/500
|
|
@cindex H8/500 line comment character
|
|
@samp{!} is the line comment character.
|
|
|
|
@cindex line separator, H8/500
|
|
@cindex statement separator, H8/500
|
|
@cindex H8/500 line separator
|
|
@samp{;} can be used instead of a newline to separate statements.
|
|
|
|
@cindex symbol names, @samp{$} in
|
|
@cindex @code{$} in symbol names
|
|
Since @samp{$} has no special meaning, you may use it in symbol names.
|
|
|
|
@node H8/500-Regs
|
|
@subsection Register Names
|
|
|
|
@cindex H8/500 registers
|
|
@cindex registers, H8/500
|
|
You can use the predefined symbols @samp{r0}, @samp{r1}, @samp{r2},
|
|
@samp{r3}, @samp{r4}, @samp{r5}, @samp{r6}, and @samp{r7} to refer to
|
|
the H8/500 registers.
|
|
|
|
The H8/500 also has these control registers:
|
|
|
|
@table @code
|
|
@item cp
|
|
code pointer
|
|
|
|
@item dp
|
|
data pointer
|
|
|
|
@item bp
|
|
base pointer
|
|
|
|
@item tp
|
|
stack top pointer
|
|
|
|
@item ep
|
|
extra pointer
|
|
|
|
@item sr
|
|
status register
|
|
|
|
@item ccr
|
|
condition code register
|
|
@end table
|
|
|
|
All registers are 16 bits long. To represent 32 bit numbers, use two
|
|
adjacent registers; for distant memory addresses, use one of the segment
|
|
pointers (@code{cp} for the program counter; @code{dp} for
|
|
@code{r0}--@code{r3}; @code{ep} for @code{r4} and @code{r5}; and
|
|
@code{tp} for @code{r6} and @code{r7}.
|
|
|
|
@node H8/500-Addressing
|
|
@subsection Addressing Modes
|
|
|
|
@cindex addressing modes, H8/500
|
|
@cindex H8/500 addressing modes
|
|
@value{AS} understands the following addressing modes for the H8/500:
|
|
@table @code
|
|
@item R@var{n}
|
|
Register direct
|
|
|
|
@item @@R@var{n}
|
|
Register indirect
|
|
|
|
@item @@(d:8, R@var{n})
|
|
Register indirect with 8 bit signed displacement
|
|
|
|
@item @@(d:16, R@var{n})
|
|
Register indirect with 16 bit signed displacement
|
|
|
|
@item @@-R@var{n}
|
|
Register indirect with pre-decrement
|
|
|
|
@item @@R@var{n}+
|
|
Register indirect with post-increment
|
|
|
|
@item @@@var{aa}:8
|
|
8 bit absolute address
|
|
|
|
@item @@@var{aa}:16
|
|
16 bit absolute address
|
|
|
|
@item #@var{xx}:8
|
|
8 bit immediate
|
|
|
|
@item #@var{xx}:16
|
|
16 bit immediate
|
|
@end table
|
|
|
|
@node H8/500 Floating Point
|
|
@section Floating Point
|
|
|
|
@cindex floating point, H8/500 (@sc{ieee})
|
|
@cindex H8/500 floating point (@sc{ieee})
|
|
The H8/500 family uses @sc{ieee} floating-point numbers.
|
|
|
|
@node H8/500 Directives
|
|
@section H8/500 Machine Directives
|
|
|
|
@cindex H8/500 machine directives (none)
|
|
@cindex machine directives, H8/500 (none)
|
|
@cindex @code{word} directive, H8/500
|
|
@cindex @code{int} directive, H8/500
|
|
@code{@value{AS}} has no machine-dependent directives for the H8/500.
|
|
However, on this platform the @samp{.int} and @samp{.word} directives
|
|
generate 16-bit numbers.
|
|
|
|
@node H8/500 Opcodes
|
|
@section Opcodes
|
|
|
|
@cindex H8/500 opcode summary
|
|
@cindex opcode summary, H8/500
|
|
@cindex mnemonics, H8/500
|
|
@cindex instruction summary, H8/500
|
|
For detailed information on the H8/500 machine instruction set, see
|
|
@cite{H8/500 Series Programming Manual} (Hitachi M21T001).
|
|
|
|
@code{@value{AS}} implements all the standard H8/500 opcodes. No additional
|
|
pseudo-instructions are needed on this family.
|
|
|
|
@ifset SMALL
|
|
@c this table, due to the multi-col faking and hardcoded order, looks silly
|
|
@c except in smallbook. See comments below "@set SMALL" near top of this file.
|
|
|
|
The following table summarizes H8/500 opcodes and their operands:
|
|
|
|
@c Use @group if it ever works, instead of @page
|
|
@page
|
|
@smallexample
|
|
@i{Legend:}
|
|
abs8 @r{8-bit absolute address}
|
|
abs16 @r{16-bit absolute address}
|
|
abs24 @r{24-bit absolute address}
|
|
crb @r{@code{ccr}, @code{br}, @code{ep}, @code{dp}, @code{tp}, @code{dp}}
|
|
disp8 @r{8-bit displacement}
|
|
ea @r{@code{rn}, @code{@@rn}, @code{@@(d:8, rn)}, @code{@@(d:16, rn)},}
|
|
@r{@code{@@-rn}, @code{@@rn+}, @code{@@aa:8}, @code{@@aa:16},}
|
|
@r{@code{#xx:8}, @code{#xx:16}}
|
|
ea_mem @r{@code{@@rn}, @code{@@(d:8, rn)}, @code{@@(d:16, rn)},}
|
|
@r{@code{@@-rn}, @code{@@rn+}, @code{@@aa:8}, @code{@@aa:16}}
|
|
ea_noimm @r{@code{rn}, @code{@@rn}, @code{@@(d:8, rn)}, @code{@@(d:16, rn)},}
|
|
@r{@code{@@-rn}, @code{@@rn+}, @code{@@aa:8}, @code{@@aa:16}}
|
|
fp r6
|
|
imm4 @r{4-bit immediate data}
|
|
imm8 @r{8-bit immediate data}
|
|
imm16 @r{16-bit immediate data}
|
|
pcrel8 @r{8-bit offset from program counter}
|
|
pcrel16 @r{16-bit offset from program counter}
|
|
qim @r{@code{-2}, @code{-1}, @code{1}, @code{2}}
|
|
rd @r{any register}
|
|
rs @r{a register distinct from rd}
|
|
rlist @r{comma-separated list of registers in parentheses;}
|
|
@r{register ranges @code{rd-rs} are allowed}
|
|
sp @r{stack pointer (@code{r7})}
|
|
sr @r{status register}
|
|
sz @r{size; @samp{.b} or @samp{.w}. If omitted, default @samp{.w}}
|
|
|
|
ldc[.b] ea,crb bcc[.w] pcrel16
|
|
ldc[.w] ea,sr bcc[.b] pcrel8
|
|
add[:q] sz qim,ea_noimm bhs[.w] pcrel16
|
|
add[:g] sz ea,rd bhs[.b] pcrel8
|
|
adds sz ea,rd bcs[.w] pcrel16
|
|
addx sz ea,rd bcs[.b] pcrel8
|
|
and sz ea,rd blo[.w] pcrel16
|
|
andc[.b] imm8,crb blo[.b] pcrel8
|
|
andc[.w] imm16,sr bne[.w] pcrel16
|
|
bpt bne[.b] pcrel8
|
|
bra[.w] pcrel16 beq[.w] pcrel16
|
|
bra[.b] pcrel8 beq[.b] pcrel8
|
|
bt[.w] pcrel16 bvc[.w] pcrel16
|
|
bt[.b] pcrel8 bvc[.b] pcrel8
|
|
brn[.w] pcrel16 bvs[.w] pcrel16
|
|
brn[.b] pcrel8 bvs[.b] pcrel8
|
|
bf[.w] pcrel16 bpl[.w] pcrel16
|
|
bf[.b] pcrel8 bpl[.b] pcrel8
|
|
bhi[.w] pcrel16 bmi[.w] pcrel16
|
|
bhi[.b] pcrel8 bmi[.b] pcrel8
|
|
bls[.w] pcrel16 bge[.w] pcrel16
|
|
bls[.b] pcrel8 bge[.b] pcrel8
|
|
@page
|
|
blt[.w] pcrel16 mov[:g][.b] imm8,ea_mem
|
|
blt[.b] pcrel8 mov[:g][.w] imm16,ea_mem
|
|
bgt[.w] pcrel16 movfpe[.b] ea,rd
|
|
bgt[.b] pcrel8 movtpe[.b] rs,ea_noimm
|
|
ble[.w] pcrel16 mulxu sz ea,rd
|
|
ble[.b] pcrel8 neg sz ea
|
|
bclr sz imm4,ea_noimm nop
|
|
bclr sz rs,ea_noimm not sz ea
|
|
bnot sz imm4,ea_noimm or sz ea,rd
|
|
bnot sz rs,ea_noimm orc[.b] imm8,crb
|
|
bset sz imm4,ea_noimm orc[.w] imm16,sr
|
|
bset sz rs,ea_noimm pjmp abs24
|
|
bsr[.b] pcrel8 pjmp @@rd
|
|
bsr[.w] pcrel16 pjsr abs24
|
|
btst sz imm4,ea_noimm pjsr @@rd
|
|
btst sz rs,ea_noimm prtd imm8
|
|
clr sz ea prtd imm16
|
|
cmp[:e][.b] imm8,rd prts
|
|
cmp[:i][.w] imm16,rd rotl sz ea
|
|
cmp[:g].b imm8,ea_noimm rotr sz ea
|
|
cmp[:g][.w] imm16,ea_noimm rotxl sz ea
|
|
Cmp[:g] sz ea,rd rotxr sz ea
|
|
dadd rs,rd rtd imm8
|
|
divxu sz ea,rd rtd imm16
|
|
dsub rs,rd rts
|
|
exts[.b] rd scb/f rs,pcrel8
|
|
extu[.b] rd scb/ne rs,pcrel8
|
|
jmp @@rd scb/eq rs,pcrel8
|
|
jmp @@(imm8,rd) shal sz ea
|
|
jmp @@(imm16,rd) shar sz ea
|
|
jmp abs16 shll sz ea
|
|
jsr @@rd shlr sz ea
|
|
jsr @@(imm8,rd) sleep
|
|
jsr @@(imm16,rd) stc[.b] crb,ea_noimm
|
|
jsr abs16 stc[.w] sr,ea_noimm
|
|
ldm @@sp+,(rlist) stm (rlist),@@-sp
|
|
link fp,imm8 sub sz ea,rd
|
|
link fp,imm16 subs sz ea,rd
|
|
mov[:e][.b] imm8,rd subx sz ea,rd
|
|
mov[:i][.w] imm16,rd swap[.b] rd
|
|
mov[:l][.w] abs8,rd tas[.b] ea
|
|
mov[:l].b abs8,rd trapa imm4
|
|
mov[:s][.w] rs,abs8 trap/vs
|
|
mov[:s].b rs,abs8 tst sz ea
|
|
mov[:f][.w] @@(disp8,fp),rd unlk fp
|
|
mov[:f][.w] rs,@@(disp8,fp) xch[.w] rs,rd
|
|
mov[:f].b @@(disp8,fp),rd xor sz ea,rd
|
|
mov[:f].b rs,@@(disp8,fp) xorc.b imm8,crb
|
|
mov[:g] sz rs,ea_mem xorc.w imm16,sr
|
|
mov[:g] sz ea,rd
|
|
@end smallexample
|
|
@end ifset
|
|
@end ifset
|
|
|
|
@ifset HPPA
|
|
@page
|
|
@node HPPA-Dependent
|
|
@chapter HPPA Dependent Features
|
|
|
|
@cindex support
|
|
@menu
|
|
* HPPA Notes:: Notes
|
|
* HPPA Options:: Options
|
|
* HPPA Syntax:: Syntax
|
|
* HPPA Floating Point:: Floating Point
|
|
* HPPA Directives:: HPPA Machine Directives
|
|
* HPPA Opcodes:: Opcodes
|
|
@end menu
|
|
|
|
@node HPPA Notes
|
|
@section Notes
|
|
As a back end for @sc{gnu} @sc{cc} @code{@value{AS}} has been throughly tested and should
|
|
work extremely well. We have tested it only minimally on hand written assembly
|
|
code and no one has tested it much on the assembly output from the HP
|
|
compilers.
|
|
|
|
The format of the debugging sections has changed since the original
|
|
@code{@value{AS}} port (version 1.3X) was released; therefore,
|
|
you must rebuild all HPPA objects and libraries with the new
|
|
assembler so that you can debug the final executable.
|
|
|
|
The HPPA @code{@value{AS}} port generates a small subset of the relocations
|
|
available in the SOM and ELF object file formats. Additional relocation
|
|
support will be added as it becomes necessary.
|
|
|
|
@node HPPA Options
|
|
@section Options
|
|
@code{@value{AS}} has no machine-dependent command-line options for the HPPA.
|
|
|
|
@cindex HPPA Syntax
|
|
@node HPPA Syntax
|
|
@section Syntax
|
|
The assembler syntax closely follows the HPPA instruction set
|
|
reference manual; assembler directives and general syntax closely follow the
|
|
HPPA assembly language reference manual, with a few noteworthy differences.
|
|
|
|
First, a colon may immediately follow a label definition. This is
|
|
simply for compatibility with how most assembly language programmers
|
|
write code.
|
|
|
|
Some obscure expression parsing problems may affect hand written code which
|
|
uses the @code{spop} instructions, or code which makes significant
|
|
use of the @code{!} line separator.
|
|
|
|
@code{@value{AS}} is much less forgiving about missing arguments and other
|
|
similar oversights than the HP assembler. @code{@value{AS}} notifies you
|
|
of missing arguments as syntax errors; this is regarded as a feature, not a
|
|
bug.
|
|
|
|
Finally, @code{@value{AS}} allows you to use an external symbol without
|
|
explicitly importing the symbol. @emph{Warning:} in the future this will be
|
|
an error for HPPA targets.
|
|
|
|
Special characters for HPPA targets include:
|
|
|
|
@samp{;} is the line comment character.
|
|
|
|
@samp{!} can be used instead of a newline to separate statements.
|
|
|
|
Since @samp{$} has no special meaning, you may use it in symbol names.
|
|
|
|
@node HPPA Floating Point
|
|
@section Floating Point
|
|
@cindex floating point, HPPA (@sc{ieee})
|
|
@cindex HPPA floating point (@sc{ieee})
|
|
The HPPA family uses @sc{ieee} floating-point numbers.
|
|
|
|
@node HPPA Directives
|
|
@section HPPA Assembler Directives
|
|
|
|
@code{@value{AS}} for the HPPA supports many additional directives for
|
|
compatibility with the native assembler. This section describes them only
|
|
briefly. For detailed information on HPPA-specific assembler directives, see
|
|
@cite{HP9000 Series 800 Assembly Language Reference Manual} (HP 92432-90001).
|
|
|
|
@cindex HPPA directives not supported
|
|
@code{@value{AS}} does @emph{not} support the following assembler directives
|
|
described in the HP manual:
|
|
|
|
@example
|
|
.endm .liston
|
|
.enter .locct
|
|
.leave .macro
|
|
.listoff
|
|
@end example
|
|
|
|
@cindex @code{.param} on HPPA
|
|
Beyond those implemented for compatibility, @code{@value{AS}} supports one
|
|
additional assembler directive for the HPPA: @code{.param}. It conveys
|
|
register argument locations for static functions. Its syntax closely follows
|
|
the @code{.export} directive.
|
|
|
|
@cindex HPPA-only directives
|
|
These are the additional directives in @code{@value{AS}} for the HPPA:
|
|
|
|
@table @code
|
|
@item .block @var{n}
|
|
@itemx .blockz @var{n}
|
|
Reserve @var{n} bytes of storage, and initialize them to zero.
|
|
|
|
@item .call
|
|
Mark the beginning of a procedure call. Only the special case with @emph{no
|
|
arguments} is allowed.
|
|
|
|
@item .callinfo [ @var{param}=@var{value}, @dots{} ] [ @var{flag}, @dots{} ]
|
|
Specify a number of parameters and flags that define the environment for a
|
|
procedure.
|
|
|
|
@var{param} may be any of @samp{frame} (frame size), @samp{entry_gr} (end of
|
|
general register range), @samp{entry_fr} (end of float register range),
|
|
@samp{entry_sr} (end of space register range).
|
|
|
|
The values for @var{flag} are @samp{calls} or @samp{caller} (proc has
|
|
subroutines), @samp{no_calls} (proc does not call subroutines), @samp{save_rp}
|
|
(preserve return pointer), @samp{save_sp} (proc preserves stack pointer),
|
|
@samp{no_unwind} (do not unwind this proc), @samp{hpux_int} (proc is interrupt
|
|
routine).
|
|
|
|
@item .code
|
|
Assemble into the standard section called @samp{$TEXT$}, subsection
|
|
@samp{$CODE$}.
|
|
|
|
@ifset SOM
|
|
@item .copyright "@var{string}"
|
|
In the SOM object format, insert @var{string} into the object code, marked as a
|
|
copyright string.
|
|
@end ifset
|
|
|
|
@ifset ELF
|
|
@item .copyright "@var{string}"
|
|
In the ELF object format, insert @var{string} into the object code, marked as a
|
|
version string.
|
|
@end ifset
|
|
|
|
@item .enter
|
|
Not yet supported; the assembler rejects programs containing this directive.
|
|
|
|
@item .entry
|
|
Mark the beginning of a procedure.
|
|
|
|
@item .exit
|
|
Mark the end of a procedure.
|
|
|
|
@item .export @var{name} [ ,@var{typ} ] [ ,@var{param}=@var{r} ]
|
|
Make a procedure @var{name} available to callers. @var{typ}, if present, must
|
|
be one of @samp{absolute}, @samp{code} (ELF only, not SOM), @samp{data},
|
|
@samp{entry}, @samp{data}, @samp{entry}, @samp{millicode}, @samp{plabel},
|
|
@samp{pri_prog}, or @samp{sec_prog}.
|
|
|
|
@var{param}, if present, provides either relocation information for the
|
|
procedure arguments and result, or a privilege level. @var{param} may be
|
|
@samp{argw@var{n}} (where @var{n} ranges from @code{0} to @code{3}, and
|
|
indicates one of four one-word arguments); @samp{rtnval} (the procedure's
|
|
result); or @samp{priv_lev} (privilege level). For arguments or the result,
|
|
@var{r} specifies how to relocate, and must be one of @samp{no} (not
|
|
relocatable), @samp{gr} (argument is in general register), @samp{fr} (in
|
|
floating point register), or @samp{fu} (upper half of float register).
|
|
For @samp{priv_lev}, @var{r} is an integer.
|
|
|
|
@item .half @var{n}
|
|
Define a two-byte integer constant @var{n}; synonym for the portable
|
|
@code{@value{AS}} directive @code{.short}.
|
|
|
|
@item .import @var{name} [ ,@var{typ} ]
|
|
Converse of @code{.export}; make a procedure available to call. The arguments
|
|
use the same conventions as the first two arguments for @code{.export}.
|
|
|
|
@item .label @var{name}
|
|
Define @var{name} as a label for the current assembly location.
|
|
|
|
@item .leave
|
|
Not yet supported; the assembler rejects programs containing this directive.
|
|
|
|
@item .origin @var{lc}
|
|
Advance location counter to @var{lc}. Synonym for the @code{@value{as}}
|
|
portable directive @code{.org}.
|
|
|
|
@item .param @var{name} [ ,@var{typ} ] [ ,@var{param}=@var{r} ]
|
|
@c Not in HP manual; GNU HPPA extension
|
|
Similar to @code{.export}, but used for static procedures.
|
|
|
|
@item .proc
|
|
Use preceding the first statement of a procedure.
|
|
|
|
@item .procend
|
|
Use following the last statement of a procedure.
|
|
|
|
@item @var{label} .reg @var{expr}
|
|
@c ?? Not in HP manual (Jan 1988 vn)
|
|
Synonym for @code{.equ}; define @var{label} with the absolute expression
|
|
@var{expr} as its value.
|
|
|
|
@item .space @var{secname} [ ,@var{params} ]
|
|
Switch to section @var{secname}, creating a new section by that name if
|
|
necessary. You may only use @var{params} when creating a new section, not
|
|
when switching to an existing one. @var{secname} may identify a section by
|
|
number rather than by name.
|
|
|
|
If specified, the list @var{params} declares attributes of the section,
|
|
identified by keywords. The keywords recognized are @samp{spnum=@var{exp}}
|
|
(identify this section by the number @var{exp}, an absolute expression),
|
|
@samp{sort=@var{exp}} (order sections according to this sort key when linking;
|
|
@var{exp} is an absolute expression), @samp{unloadable} (section contains no
|
|
loadable data), @samp{notdefined} (this section defined elsewhere), and
|
|
@samp{private} (data in this section not available to other programs).
|
|
|
|
@item .spnum @var{secnam}
|
|
@c ?? Not in HP manual (Jan 1988)
|
|
Allocate four bytes of storage, and initialize them with the section number of
|
|
the section named @var{secnam}. (You can define the section number with the
|
|
HPPA @code{.space} directive.)
|
|
|
|
@item .string "@var{str}"
|
|
@cindex @code{string} directive on HPPA
|
|
Copy the characters in the string @var{str} to the object file.
|
|
@xref{Strings,,Strings}, for information on escape sequences you can use in
|
|
@code{@value{AS}} strings.
|
|
|
|
@emph{Warning!} The HPPA version of @code{.string} differs from the
|
|
usual @code{@value{AS}} definition: it does @emph{not} write a zero byte
|
|
after copying @var{str}.
|
|
|
|
@item .stringz "@var{str}"
|
|
Like @code{.string}, but appends a zero byte after copying @var{str} to object
|
|
file.
|
|
|
|
@item .subspa @var{name} [ ,@var{params} ]
|
|
Similar to @code{.space}, but selects a subsection @var{name} within the
|
|
current section. You may only specify @var{params} when you create a
|
|
subsection (in the first instance of @code{.subspa} for this @var{name}).
|
|
|
|
If specified, the list @var{params} declares attributes of the subsection,
|
|
identified by keywords. The keywords recognized are @samp{quad=@var{expr}}
|
|
(``quadrant'' for this subsection), @samp{align=@var{expr}} (alignment for
|
|
beginning of this subsection; a power of two), @samp{access=@var{expr}} (value
|
|
for ``access rights'' field), @samp{sort=@var{expr}} (sorting order for this
|
|
subspace in link), @samp{code_only} (subsection contains only code),
|
|
@samp{unloadable} (subsection cannot be loaded into memory), @samp{common}
|
|
(subsection is common block), @samp{dup_comm} (initialized data may have
|
|
duplicate names), or @samp{zero} (subsection is all zeros, do not write in
|
|
object file).
|
|
|
|
@item .version "@var{str}"
|
|
Write @var{str} as version identifier in object code.
|
|
@end table
|
|
|
|
@node HPPA Opcodes
|
|
@section Opcodes
|
|
For detailed information on the HPPA machine instruction set, see
|
|
@cite{PA-RISC Architecture and Instruction Set Reference Manual}
|
|
(HP 09740-90039).
|
|
@end ifset
|
|
|
|
@ifset SH
|
|
@page
|
|
@node SH-Dependent
|
|
@chapter Hitachi SH Dependent Features
|
|
|
|
@cindex SH support
|
|
@menu
|
|
* SH Options:: Options
|
|
* SH Syntax:: Syntax
|
|
* SH Floating Point:: Floating Point
|
|
* SH Directives:: SH Machine Directives
|
|
* SH Opcodes:: Opcodes
|
|
@end menu
|
|
|
|
@node SH Options
|
|
@section Options
|
|
|
|
@cindex SH options (none)
|
|
@cindex options, SH (none)
|
|
@code{@value{AS}} has no additional command-line options for the Hitachi
|
|
SH family.
|
|
|
|
@node SH Syntax
|
|
@section Syntax
|
|
|
|
@menu
|
|
* SH-Chars:: Special Characters
|
|
* SH-Regs:: Register Names
|
|
* SH-Addressing:: Addressing Modes
|
|
@end menu
|
|
|
|
@node SH-Chars
|
|
@subsection Special Characters
|
|
|
|
@cindex line comment character, SH
|
|
@cindex SH line comment character
|
|
@samp{!} is the line comment character.
|
|
|
|
@cindex line separator, SH
|
|
@cindex statement separator, SH
|
|
@cindex SH line separator
|
|
You can use @samp{;} instead of a newline to separate statements.
|
|
|
|
@cindex symbol names, @samp{$} in
|
|
@cindex @code{$} in symbol names
|
|
Since @samp{$} has no special meaning, you may use it in symbol names.
|
|
|
|
@node SH-Regs
|
|
@subsection Register Names
|
|
|
|
@cindex SH registers
|
|
@cindex registers, SH
|
|
You can use the predefined symbols @samp{r0}, @samp{r1}, @samp{r2},
|
|
@samp{r3}, @samp{r4}, @samp{r5}, @samp{r6}, @samp{r7}, @samp{r8},
|
|
@samp{r9}, @samp{r10}, @samp{r11}, @samp{r12}, @samp{r13}, @samp{r14},
|
|
and @samp{r15} to refer to the SH registers.
|
|
|
|
The SH also has these control registers:
|
|
|
|
@table @code
|
|
@item pr
|
|
procedure register (holds return address)
|
|
|
|
@item pc
|
|
program counter
|
|
|
|
@item mach
|
|
@itemx macl
|
|
high and low multiply accumulator registers
|
|
|
|
@item sr
|
|
status register
|
|
|
|
@item gbr
|
|
global base register
|
|
|
|
@item vbr
|
|
vector base register (for interrupt vectors)
|
|
@end table
|
|
|
|
@node SH-Addressing
|
|
@subsection Addressing Modes
|
|
|
|
@cindex addressing modes, SH
|
|
@cindex SH addressing modes
|
|
@code{@value{AS}} understands the following addressing modes for the SH.
|
|
@code{R@var{n}} in the following refers to any of the numbered
|
|
registers, but @emph{not} the control registers.
|
|
|
|
@table @code
|
|
@item R@var{n}
|
|
Register direct
|
|
|
|
@item @@R@var{n}
|
|
Register indirect
|
|
|
|
@item @@-R@var{n}
|
|
Register indirect with pre-decrement
|
|
|
|
@item @@R@var{n}+
|
|
Register indirect with post-increment
|
|
|
|
@item @@(@var{disp}, R@var{n})
|
|
Register indirect with displacement
|
|
|
|
@item @@(R0, R@var{n})
|
|
Register indexed
|
|
|
|
@item @@(@var{disp}, GBR)
|
|
@code{GBR} offset
|
|
|
|
@item @@(R0, GBR)
|
|
GBR indexed
|
|
|
|
@item @var{addr}
|
|
@itemx @@(@var{disp}, PC)
|
|
PC relative address (for branch or for addressing memory). The
|
|
@code{@value{AS}} implementation allows you to use the simpler form
|
|
@var{addr} anywhere a PC relative address is called for; the alternate
|
|
form is supported for compatibility with other assemblers.
|
|
|
|
@item #@var{imm}
|
|
Immediate data
|
|
@end table
|
|
|
|
@node SH Floating Point
|
|
@section Floating Point
|
|
|
|
@cindex floating point, SH (@sc{ieee})
|
|
@cindex SH floating point (@sc{ieee})
|
|
The SH family uses @sc{ieee} floating-point numbers.
|
|
|
|
@node SH Directives
|
|
@section SH Machine Directives
|
|
|
|
@cindex SH machine directives (none)
|
|
@cindex machine directives, SH (none)
|
|
@cindex @code{word} directive, SH
|
|
@cindex @code{int} directive, SH
|
|
@code{@value{AS}} has no machine-dependent directives for the SH.
|
|
|
|
@node SH Opcodes
|
|
@section Opcodes
|
|
|
|
@cindex SH opcode summary
|
|
@cindex opcode summary, SH
|
|
@cindex mnemonics, SH
|
|
@cindex instruction summary, SH
|
|
For detailed information on the SH machine instruction set, see
|
|
@cite{SH-Microcomputer User's Manual} (Hitachi Micro Systems, Inc.).
|
|
|
|
@code{@value{AS}} implements all the standard SH opcodes. No additional
|
|
pseudo-instructions are needed on this family. Note, however, that
|
|
because @code{@value{AS}} supports a simpler form of PC-relative
|
|
addressing, you may simply write (for example)
|
|
|
|
@example
|
|
mov.l bar,r0
|
|
@end example
|
|
|
|
@noindent
|
|
where other assemblers might require an explicit displacement to
|
|
@code{bar} from the program counter:
|
|
|
|
@example
|
|
mov.l @@(@var{disp}, PC)
|
|
@end example
|
|
|
|
@ifset SMALL
|
|
@c this table, due to the multi-col faking and hardcoded order, looks silly
|
|
@c except in smallbook. See comments below "@set SMALL" near top of this file.
|
|
|
|
Here is a summary of SH opcodes:
|
|
|
|
@page
|
|
@smallexample
|
|
@i{Legend:}
|
|
Rn @r{a numbered register}
|
|
Rm @r{another numbered register}
|
|
#imm @r{immediate data}
|
|
disp @r{displacement}
|
|
disp8 @r{8-bit displacement}
|
|
disp12 @r{12-bit displacement}
|
|
|
|
add #imm,Rn lds.l @@Rn+,PR
|
|
add Rm,Rn mac.w @@Rm+,@@Rn+
|
|
addc Rm,Rn mov #imm,Rn
|
|
addv Rm,Rn mov Rm,Rn
|
|
and #imm,R0 mov.b Rm,@@(R0,Rn)
|
|
and Rm,Rn mov.b Rm,@@-Rn
|
|
and.b #imm,@@(R0,GBR) mov.b Rm,@@Rn
|
|
bf disp8 mov.b @@(disp,Rm),R0
|
|
bra disp12 mov.b @@(disp,GBR),R0
|
|
bsr disp12 mov.b @@(R0,Rm),Rn
|
|
bt disp8 mov.b @@Rm+,Rn
|
|
clrmac mov.b @@Rm,Rn
|
|
clrt mov.b R0,@@(disp,Rm)
|
|
cmp/eq #imm,R0 mov.b R0,@@(disp,GBR)
|
|
cmp/eq Rm,Rn mov.l Rm,@@(disp,Rn)
|
|
cmp/ge Rm,Rn mov.l Rm,@@(R0,Rn)
|
|
cmp/gt Rm,Rn mov.l Rm,@@-Rn
|
|
cmp/hi Rm,Rn mov.l Rm,@@Rn
|
|
cmp/hs Rm,Rn mov.l @@(disp,Rn),Rm
|
|
cmp/pl Rn mov.l @@(disp,GBR),R0
|
|
cmp/pz Rn mov.l @@(disp,PC),Rn
|
|
cmp/str Rm,Rn mov.l @@(R0,Rm),Rn
|
|
div0s Rm,Rn mov.l @@Rm+,Rn
|
|
div0u mov.l @@Rm,Rn
|
|
div1 Rm,Rn mov.l R0,@@(disp,GBR)
|
|
exts.b Rm,Rn mov.w Rm,@@(R0,Rn)
|
|
exts.w Rm,Rn mov.w Rm,@@-Rn
|
|
extu.b Rm,Rn mov.w Rm,@@Rn
|
|
extu.w Rm,Rn mov.w @@(disp,Rm),R0
|
|
jmp @@Rn mov.w @@(disp,GBR),R0
|
|
jsr @@Rn mov.w @@(disp,PC),Rn
|
|
ldc Rn,GBR mov.w @@(R0,Rm),Rn
|
|
ldc Rn,SR mov.w @@Rm+,Rn
|
|
ldc Rn,VBR mov.w @@Rm,Rn
|
|
ldc.l @@Rn+,GBR mov.w R0,@@(disp,Rm)
|
|
ldc.l @@Rn+,SR mov.w R0,@@(disp,GBR)
|
|
ldc.l @@Rn+,VBR mova @@(disp,PC),R0
|
|
lds Rn,MACH movt Rn
|
|
lds Rn,MACL muls Rm,Rn
|
|
lds Rn,PR mulu Rm,Rn
|
|
lds.l @@Rn+,MACH neg Rm,Rn
|
|
lds.l @@Rn+,MACL negc Rm,Rn
|
|
@page
|
|
nop stc VBR,Rn
|
|
not Rm,Rn stc.l GBR,@@-Rn
|
|
or #imm,R0 stc.l SR,@@-Rn
|
|
or Rm,Rn stc.l VBR,@@-Rn
|
|
or.b #imm,@@(R0,GBR) sts MACH,Rn
|
|
rotcl Rn sts MACL,Rn
|
|
rotcr Rn sts PR,Rn
|
|
rotl Rn sts.l MACH,@@-Rn
|
|
rotr Rn sts.l MACL,@@-Rn
|
|
rte sts.l PR,@@-Rn
|
|
rts sub Rm,Rn
|
|
sett subc Rm,Rn
|
|
shal Rn subv Rm,Rn
|
|
shar Rn swap.b Rm,Rn
|
|
shll Rn swap.w Rm,Rn
|
|
shll16 Rn tas.b @@Rn
|
|
shll2 Rn trapa #imm
|
|
shll8 Rn tst #imm,R0
|
|
shlr Rn tst Rm,Rn
|
|
shlr16 Rn tst.b #imm,@@(R0,GBR)
|
|
shlr2 Rn xor #imm,R0
|
|
shlr8 Rn xor Rm,Rn
|
|
sleep xor.b #imm,@@(R0,GBR)
|
|
stc GBR,Rn xtrct Rm,Rn
|
|
stc SR,Rn
|
|
@end smallexample
|
|
@end ifset
|
|
|
|
@ifset Hitachi-all
|
|
@ifclear GENERIC
|
|
@raisesections
|
|
@end ifclear
|
|
@end ifset
|
|
|
|
@end ifset
|
|
@ifset I960
|
|
@ifset GENERIC
|
|
@page
|
|
@node i960-Dependent
|
|
@chapter Intel 80960 Dependent Features
|
|
@end ifset
|
|
@ifclear GENERIC
|
|
@node Machine Dependencies
|
|
@chapter Intel 80960 Dependent Features
|
|
@end ifclear
|
|
|
|
@cindex i960 support
|
|
@menu
|
|
* Options-i960:: i960 Command-line Options
|
|
* Floating Point-i960:: Floating Point
|
|
* Directives-i960:: i960 Machine Directives
|
|
* Opcodes for i960:: i960 Opcodes
|
|
@end menu
|
|
|
|
@c FIXME! Add Syntax sec with discussion of bitfields here, at least so
|
|
@c long as they're not turned on for other machines than 960.
|
|
|
|
@node Options-i960
|
|
|
|
@section i960 Command-line Options
|
|
|
|
@cindex i960 options
|
|
@cindex options, i960
|
|
@table @code
|
|
|
|
@item -ACA | -ACA_A | -ACB | -ACC | -AKA | -AKB | -AKC | -AMC
|
|
@cindex i960 architecture options
|
|
@cindex architecture options, i960
|
|
@cindex @code{-A} options, i960
|
|
Select the 80960 architecture. Instructions or features not supported
|
|
by the selected architecture cause fatal errors.
|
|
|
|
@samp{-ACA} is equivalent to @samp{-ACA_A}; @samp{-AKC} is equivalent to
|
|
@samp{-AMC}. Synonyms are provided for compatibility with other tools.
|
|
|
|
If you do not specify any of these options, @code{@value{AS}} generates code
|
|
for any instruction or feature that is supported by @emph{some} version of the
|
|
960 (even if this means mixing architectures!). In principle,
|
|
@code{@value{AS}} attempts to deduce the minimal sufficient processor type if
|
|
none is specified; depending on the object code format, the processor type may
|
|
be recorded in the object file. If it is critical that the @code{@value{AS}}
|
|
output match a specific architecture, specify that architecture explicitly.
|
|
|
|
@item -b
|
|
@cindex @code{-b} option, i960
|
|
@cindex branch recording, i960
|
|
@cindex i960 branch recording
|
|
Add code to collect information about conditional branches taken, for
|
|
later optimization using branch prediction bits. (The conditional branch
|
|
instructions have branch prediction bits in the CA, CB, and CC
|
|
architectures.) If @var{BR} represents a conditional branch instruction,
|
|
the following represents the code generated by the assembler when
|
|
@samp{-b} is specified:
|
|
|
|
@smallexample
|
|
call @var{increment routine}
|
|
.word 0 # pre-counter
|
|
Label: @var{BR}
|
|
call @var{increment routine}
|
|
.word 0 # post-counter
|
|
@end smallexample
|
|
|
|
The counter following a branch records the number of times that branch
|
|
was @emph{not} taken; the differenc between the two counters is the
|
|
number of times the branch @emph{was} taken.
|
|
|
|
@cindex @code{gbr960}, i960 postprocessor
|
|
@cindex branch statistics table, i960
|
|
A table of every such @code{Label} is also generated, so that the
|
|
external postprocessor @code{gbr960} (supplied by Intel) can locate all
|
|
the counters. This table is always labelled @samp{__BRANCH_TABLE__};
|
|
this is a local symbol to permit collecting statistics for many separate
|
|
object files. The table is word aligned, and begins with a two-word
|
|
header. The first word, initialized to 0, is used in maintaining linked
|
|
lists of branch tables. The second word is a count of the number of
|
|
entries in the table, which follow immediately: each is a word, pointing
|
|
to one of the labels illustrated above.
|
|
|
|
@c TEXI2ROFF-KILL
|
|
@ifinfo
|
|
@c END TEXI2ROFF-KILL
|
|
@example
|
|
+------------+------------+------------+ ... +------------+
|
|
| | | | | |
|
|
| *NEXT | COUNT: N | *BRLAB 1 | | *BRLAB N |
|
|
| | | | | |
|
|
+------------+------------+------------+ ... +------------+
|
|
|
|
__BRANCH_TABLE__ layout
|
|
@end example
|
|
@c TEXI2ROFF-KILL
|
|
@end ifinfo
|
|
@need 2000
|
|
@tex
|
|
\vskip 1pc
|
|
\line{\leftskip=0pt\hskip\tableindent
|
|
\boxit{2cm}{\tt *NEXT}\boxit{2cm}{\tt COUNT: \it N}\boxit{2cm}{\tt
|
|
*BRLAB 1}\ibox{1cm}{\quad\dots}\boxit{2cm}{\tt *BRLAB \it N}\hfil}
|
|
\centerline{\it {\tt \_\_BRANCH\_TABLE\_\_} layout}
|
|
@end tex
|
|
@c END TEXI2ROFF-KILL
|
|
|
|
The first word of the header is used to locate multiple branch tables,
|
|
since each object file may contain one. Normally the links are
|
|
maintained with a call to an initialization routine, placed at the
|
|
beginning of each function in the file. The @sc{gnu} C compiler
|
|
generates these calls automatically when you give it a @samp{-b} option.
|
|
For further details, see the documentation of @samp{gbr960}.
|
|
|
|
@item -no-relax
|
|
@cindex @code{-no-relax} option, i960
|
|
Normally, Compare-and-Branch instructions with targets that require
|
|
displacements greater than 13 bits (or that have external targets) are
|
|
replaced with the corresponding compare (or @samp{chkbit}) and branch
|
|
instructions. You can use the @samp{-no-relax} option to specify that
|
|
@code{@value{AS}} should generate errors instead, if the target displacement
|
|
is larger than 13 bits.
|
|
|
|
This option does not affect the Compare-and-Jump instructions; the code
|
|
emitted for them is @emph{always} adjusted when necessary (depending on
|
|
displacement size), regardless of whether you use @samp{-no-relax}.
|
|
@end table
|
|
|
|
@node Floating Point-i960
|
|
@section Floating Point
|
|
|
|
@cindex floating point, i960 (@sc{ieee})
|
|
@cindex i960 floating point (@sc{ieee})
|
|
@code{@value{AS}} generates @sc{ieee} floating-point numbers for the directives
|
|
@samp{.float}, @samp{.double}, @samp{.extended}, and @samp{.single}.
|
|
|
|
@node Directives-i960
|
|
@section i960 Machine Directives
|
|
|
|
@cindex machine directives, i960
|
|
@cindex i960 machine directives
|
|
|
|
@table @code
|
|
@cindex @code{bss} directive, i960
|
|
@item .bss @var{symbol}, @var{length}, @var{align}
|
|
Reserve @var{length} bytes in the bss section for a local @var{symbol},
|
|
aligned to the power of two specified by @var{align}. @var{length} and
|
|
@var{align} must be positive absolute expressions. This directive
|
|
differs from @samp{.lcomm} only in that it permits you to specify
|
|
an alignment. @xref{Lcomm,,@code{.lcomm}}.
|
|
@end table
|
|
|
|
@table @code
|
|
@item .extended @var{flonums}
|
|
@cindex @code{extended} directive, i960
|
|
@code{.extended} expects zero or more flonums, separated by commas; for
|
|
each flonum, @samp{.extended} emits an @sc{ieee} extended-format (80-bit)
|
|
floating-point number.
|
|
|
|
@item .leafproc @var{call-lab}, @var{bal-lab}
|
|
@cindex @code{leafproc} directive, i960
|
|
You can use the @samp{.leafproc} directive in conjunction with the
|
|
optimized @code{callj} instruction to enable faster calls of leaf
|
|
procedures. If a procedure is known to call no other procedures, you
|
|
may define an entry point that skips procedure prolog code (and that does
|
|
not depend on system-supplied saved context), and declare it as the
|
|
@var{bal-lab} using @samp{.leafproc}. If the procedure also has an
|
|
entry point that goes through the normal prolog, you can specify that
|
|
entry point as @var{call-lab}.
|
|
|
|
A @samp{.leafproc} declaration is meant for use in conjunction with the
|
|
optimized call instruction @samp{callj}; the directive records the data
|
|
needed later to choose between converting the @samp{callj} into a
|
|
@code{bal} or a @code{call}.
|
|
|
|
@var{call-lab} is optional; if only one argument is present, or if the
|
|
two arguments are identical, the single argument is assumed to be the
|
|
@code{bal} entry point.
|
|
|
|
@item .sysproc @var{name}, @var{index}
|
|
@cindex @code{sysproc} directive, i960
|
|
The @samp{.sysproc} directive defines a name for a system procedure.
|
|
After you define it using @samp{.sysproc}, you can use @var{name} to
|
|
refer to the system procedure identified by @var{index} when calling
|
|
procedures with the optimized call instruction @samp{callj}.
|
|
|
|
Both arguments are required; @var{index} must be between 0 and 31
|
|
(inclusive).
|
|
@end table
|
|
|
|
@node Opcodes for i960
|
|
@section i960 Opcodes
|
|
|
|
@cindex opcodes, i960
|
|
@cindex i960 opcodes
|
|
All Intel 960 machine instructions are supported;
|
|
@pxref{Options-i960,,i960 Command-line Options} for a discussion of
|
|
selecting the instruction subset for a particular 960
|
|
architecture.@refill
|
|
|
|
Some opcodes are processed beyond simply emitting a single corresponding
|
|
instruction: @samp{callj}, and Compare-and-Branch or Compare-and-Jump
|
|
instructions with target displacements larger than 13 bits.
|
|
|
|
@menu
|
|
* callj-i960:: @code{callj}
|
|
* Compare-and-branch-i960:: Compare-and-Branch
|
|
@end menu
|
|
|
|
@node callj-i960
|
|
@subsection @code{callj}
|
|
|
|
@cindex @code{callj}, i960 pseudo-opcode
|
|
@cindex i960 @code{callj} pseudo-opcode
|
|
You can write @code{callj} to have the assembler or the linker determine
|
|
the most appropriate form of subroutine call: @samp{call},
|
|
@samp{bal}, or @samp{calls}. If the assembly source contains
|
|
enough information---a @samp{.leafproc} or @samp{.sysproc} directive
|
|
defining the operand---then @code{@value{AS}} translates the
|
|
@code{callj}; if not, it simply emits the @code{callj}, leaving it
|
|
for the linker to resolve.
|
|
|
|
@node Compare-and-branch-i960
|
|
@subsection Compare-and-Branch
|
|
|
|
@cindex i960 compare/branch instructions
|
|
@cindex compare/branch instructions, i960
|
|
The 960 architectures provide combined Compare-and-Branch instructions
|
|
that permit you to store the branch target in the lower 13 bits of the
|
|
instruction word itself. However, if you specify a branch target far
|
|
enough away that its address won't fit in 13 bits, the assembler can
|
|
either issue an error, or convert your Compare-and-Branch instruction
|
|
into separate instructions to do the compare and the branch.
|
|
|
|
@cindex compare and jump expansions, i960
|
|
@cindex i960 compare and jump expansions
|
|
Whether @code{@value{AS}} gives an error or expands the instruction depends
|
|
on two choices you can make: whether you use the @samp{-no-relax} option,
|
|
and whether you use a ``Compare and Branch'' instruction or a ``Compare
|
|
and Jump'' instruction. The ``Jump'' instructions are @emph{always}
|
|
expanded if necessary; the ``Branch'' instructions are expanded when
|
|
necessary @emph{unless} you specify @code{-no-relax}---in which case
|
|
@code{@value{AS}} gives an error instead.
|
|
|
|
These are the Compare-and-Branch instructions, their ``Jump'' variants,
|
|
and the instruction pairs they may expand into:
|
|
|
|
@c TEXI2ROFF-KILL
|
|
@ifinfo
|
|
@c END TEXI2ROFF-KILL
|
|
@example
|
|
Compare and
|
|
Branch Jump Expanded to
|
|
------ ------ ------------
|
|
bbc chkbit; bno
|
|
bbs chkbit; bo
|
|
cmpibe cmpije cmpi; be
|
|
cmpibg cmpijg cmpi; bg
|
|
cmpibge cmpijge cmpi; bge
|
|
cmpibl cmpijl cmpi; bl
|
|
cmpible cmpijle cmpi; ble
|
|
cmpibno cmpijno cmpi; bno
|
|
cmpibne cmpijne cmpi; bne
|
|
cmpibo cmpijo cmpi; bo
|
|
cmpobe cmpoje cmpo; be
|
|
cmpobg cmpojg cmpo; bg
|
|
cmpobge cmpojge cmpo; bge
|
|
cmpobl cmpojl cmpo; bl
|
|
cmpoble cmpojle cmpo; ble
|
|
cmpobne cmpojne cmpo; bne
|
|
@end example
|
|
@c TEXI2ROFF-KILL
|
|
@end ifinfo
|
|
@tex
|
|
\hskip\tableindent
|
|
\halign{\hfil {\tt #}\quad&\hfil {\tt #}\qquad&{\tt #}\hfil\cr
|
|
\omit{\hfil\it Compare and\hfil}\span\omit&\cr
|
|
{\it Branch}&{\it Jump}&{\it Expanded to}\cr
|
|
bbc& & chkbit; bno\cr
|
|
bbs& & chkbit; bo\cr
|
|
cmpibe& cmpije& cmpi; be\cr
|
|
cmpibg& cmpijg& cmpi; bg\cr
|
|
cmpibge& cmpijge& cmpi; bge\cr
|
|
cmpibl& cmpijl& cmpi; bl\cr
|
|
cmpible& cmpijle& cmpi; ble\cr
|
|
cmpibno& cmpijno& cmpi; bno\cr
|
|
cmpibne& cmpijne& cmpi; bne\cr
|
|
cmpibo& cmpijo& cmpi; bo\cr
|
|
cmpobe& cmpoje& cmpo; be\cr
|
|
cmpobg& cmpojg& cmpo; bg\cr
|
|
cmpobge& cmpojge& cmpo; bge\cr
|
|
cmpobl& cmpojl& cmpo; bl\cr
|
|
cmpoble& cmpojle& cmpo; ble\cr
|
|
cmpobne& cmpojne& cmpo; bne\cr}
|
|
@end tex
|
|
@c END TEXI2ROFF-KILL
|
|
@end ifset
|
|
|
|
@ifset M680X0
|
|
@ifset GENERIC
|
|
@page
|
|
@node M68K-Dependent
|
|
@chapter M680x0 Dependent Features
|
|
@end ifset
|
|
@ifclear GENERIC
|
|
@node Machine Dependencies
|
|
@chapter M680x0 Dependent Features
|
|
@end ifclear
|
|
|
|
@cindex M680x0 support
|
|
@menu
|
|
* M68K-Opts:: M680x0 Options
|
|
* M68K-Syntax:: Syntax
|
|
* M68K-Moto-Syntax:: Motorola Syntax
|
|
* M68K-Float:: Floating Point
|
|
* M68K-Directives:: 680x0 Machine Directives
|
|
* M68K-opcodes:: Opcodes
|
|
@end menu
|
|
|
|
@node M68K-Opts
|
|
@section M680x0 Options
|
|
|
|
@cindex options, M680x0
|
|
@cindex M680x0 options
|
|
The Motorola 680x0 version of @code{@value{AS}} has two machine dependent options.
|
|
One shortens undefined references from 32 to 16 bits, while the
|
|
other is used to tell @code{@value{AS}} what kind of machine it is
|
|
assembling for.
|
|
|
|
@cindex @code{-l} option, M680x0
|
|
You can use the @samp{-l} option to shorten the size of references to undefined
|
|
symbols. If you do not use the @samp{-l} option, references to undefined
|
|
symbols are wide enough for a full @code{long} (32 bits). (Since
|
|
@code{@value{AS}} cannot know where these symbols end up, @code{@value{AS}} can
|
|
only allocate space for the linker to fill in later. Since @code{@value{AS}}
|
|
does not know how far away these symbols are, it allocates as much space as it
|
|
can.) If you use this option, the references are only one word wide (16 bits).
|
|
This may be useful if you want the object file to be as small as possible, and
|
|
you know that the relevant symbols are always less than 17 bits away.
|
|
|
|
@cindex @code{-m68000} and related options
|
|
@cindex architecture options, M680x0
|
|
@cindex M680x0 architecture options
|
|
The 680x0 version of @code{@value{AS}} is most frequently used to assemble
|
|
programs for the Motorola MC68020 microprocessor. Occasionally it is
|
|
used to assemble programs for the mostly similar, but slightly different
|
|
MC68000 or MC68010 microprocessors. You can give @code{@value{AS}} the options
|
|
@samp{-m68000}, @samp{-mc68000}, @samp{-m68010}, @samp{-mc68010},
|
|
@samp{-m68020}, and @samp{-mc68020} to tell it what processor is the
|
|
target.
|
|
|
|
@node M68K-Syntax
|
|
@section Syntax
|
|
|
|
@cindex @sc{mit}
|
|
This syntax for the Motorola 680x0 was developed at @sc{mit}.
|
|
|
|
@cindex M680x0 syntax
|
|
@cindex syntax, M680x0
|
|
@cindex M680x0 size modifiers
|
|
@cindex size modifiers, M680x0
|
|
The 680x0 version of @code{@value{AS}} uses syntax compatible with the Sun
|
|
assembler. Intervening periods are ignored; for example, @samp{movl} is
|
|
equivalent to @samp{move.l}.
|
|
|
|
@ifset INTERNALS
|
|
If @code{@value{AS}} is compiled with SUN_ASM_SYNTAX defined, it
|
|
also allows Sun-style local labels of the form @samp{1$} through
|
|
@samp{$9}.
|
|
@end ifset
|
|
|
|
In the following table @dfn{apc} stands for any of the address
|
|
registers (@samp{a0} through @samp{a7}), nothing, (@samp{}), the
|
|
Program Counter (@samp{pc}), or the zero-address relative to the
|
|
program counter (@samp{zpc}).
|
|
|
|
@cindex M680x0 addressing modes
|
|
@cindex addressing modes, M680x0
|
|
The following addressing modes are understood:
|
|
@table @dfn
|
|
@item Immediate
|
|
@samp{#@var{digits}}
|
|
|
|
@item Data Register
|
|
@samp{%d0} through @samp{%d7}
|
|
|
|
@item Address Register
|
|
@samp{%a0} through @samp{%a7}@*
|
|
@samp{%a7} is also known as @samp{%sp}, i.e. the Stack Pointer. @code{%a6}
|
|
is also known as @samp{%fp}, the Frame Pointer.
|
|
|
|
@item Address Register Indirect
|
|
@samp{%a0@@} through @samp{%a7@@}
|
|
|
|
@item Address Register Postincrement
|
|
@samp{%a0@@+} through @samp{%a7@@+}
|
|
|
|
@item Address Register Predecrement
|
|
@samp{%a0@@-} through @samp{%a7@@-}
|
|
|
|
@item Indirect Plus Offset
|
|
@samp{%@var{apc}@@(@var{digits})}
|
|
|
|
@item Index
|
|
@samp{%@var{apc}@@(@var{digits},%@var{register}:@var{size}:@var{scale})}
|
|
|
|
or @samp{%@var{apc}@@(%@var{register}:@var{size}:@var{scale})}
|
|
|
|
@item Postindex
|
|
@samp{%@var{apc}@@(@var{digits})@@(@var{digits},%@var{register}:@var{size}:@var{scale})}
|
|
|
|
or @samp{%@var{apc}@@(@var{digits})@@(%@var{register}:@var{size}:@var{scale})}
|
|
|
|
@item Preindex
|
|
@samp{%@var{apc}@@(@var{digits},%@var{register}:@var{size}:@var{scale})@@(@var{digits})}
|
|
|
|
or @samp{%@var{apc}@@(%@var{register}:@var{size}:@var{scale})@@(@var{digits})}
|
|
|
|
@item Memory Indirect
|
|
@samp{%@var{apc}@@(@var{digits})@@(@var{digits})}
|
|
|
|
@item Absolute
|
|
@samp{@var{symbol}}, or @samp{@var{digits}}
|
|
@ignore
|
|
@c pesch@cygnus.com: gnu, rich concur the following needs careful
|
|
@c research before documenting.
|
|
, or either of the above followed
|
|
by @samp{:b}, @samp{:w}, or @samp{:l}.
|
|
@end ignore
|
|
@end table
|
|
|
|
For some configurations, especially those where the compiler normally does not
|
|
prepend an underscore to the names of user variables, the assembler requires a
|
|
@samp{%} before any use of a register name. This is intended to let the
|
|
assembler distinguish between C variables and registers named @samp{a0} through
|
|
@samp{a7}, and so on. The @samp{%} is always accepted, but is not required for
|
|
certain configurations, notably @samp{sun3}.
|
|
|
|
@node M68K-Moto-Syntax
|
|
@section Motorola Syntax
|
|
|
|
@cindex Motorola syntax for the 680x0
|
|
@cindex alternate syntax for the 680x0
|
|
|
|
The standard Motorola syntax for this chip differs from the syntax already
|
|
discussed (@pxref{M68K-Syntax,,Syntax}). @code{@value{AS}} can accept some
|
|
forms of Motorola syntax for operands, even if @sc{mit} syntax is used for
|
|
other operands in the same instruction. The two kinds of syntax are fully
|
|
compatible; our support for Motorola syntax is simply incomplete at present.
|
|
|
|
@cindex M680x0 syntax
|
|
@cindex syntax, M680x0
|
|
In particular, you may write or generate M68K assembler with the
|
|
following conventions:
|
|
|
|
(In the following table @dfn{%apc} stands for any of the address registers
|
|
(@samp{%a0} through @samp{%a7}), nothing (@samp{}), the Program Counter
|
|
(@samp{%pc}), or the zero-address relative to the program counter
|
|
(@samp{%zpc}).)
|
|
|
|
@cindex M680x0 addressing modes
|
|
@cindex addressing modes, M680x0
|
|
The following additional addressing modes are understood:
|
|
@table @dfn
|
|
@item Address Register Indirect
|
|
@samp{%a0} through @samp{%a7}@*
|
|
@samp{%a7} is also known as @samp{%sp}, i.e. the Stack Pointer. @code{%a6}
|
|
is also known as @samp{%fp}, the Frame Pointer.
|
|
|
|
@item Address Register Postincrement
|
|
@samp{(%a0)+} through @samp{(%a7)+}
|
|
|
|
@item Address Register Predecrement
|
|
@samp{-(%a0)} through @samp{-(%a7)}
|
|
|
|
@item Indirect Plus Offset
|
|
@samp{@var{digits}(%@var{apc})}
|
|
|
|
@item Index
|
|
@samp{@var{digits}(%@var{apc},(%@var{register}.@var{size}*@var{scale}))}@*
|
|
or @samp{(%@var{apc},%@var{register}.@var{size}*@var{scale})}@*
|
|
In either case, @var{size} and @var{scale} are optional
|
|
(@var{scale} defaults to @samp{1}, @var{size} defaults to @samp{l}).
|
|
@var{scale} can be @samp{1}, @samp{2}, @samp{4}, or @samp{8}.
|
|
@var{size} can be @samp{w} or @samp{l}. @var{scale} is only supported
|
|
on the 68020 and greater.
|
|
@end table
|
|
|
|
Other, more complex addressing modes permitted in Motorola syntax are not
|
|
handled.
|
|
|
|
@node M68K-Float
|
|
@section Floating Point
|
|
|
|
@cindex floating point, M680x0
|
|
@cindex M680x0 floating point
|
|
@c FIXME is this "not too well tested" crud STILL true?
|
|
The floating point code is not too well tested, and may have
|
|
subtle bugs in it.
|
|
|
|
Packed decimal (P) format floating literals are not supported.
|
|
Feel free to add the code!
|
|
|
|
The floating point formats generated by directives are these.
|
|
|
|
@table @code
|
|
@item .float
|
|
@cindex @code{float} directive, M680x0
|
|
@code{Single} precision floating point constants.
|
|
|
|
@item .double
|
|
@cindex @code{double} directive, M680x0
|
|
@code{Double} precision floating point constants.
|
|
@end table
|
|
|
|
There is no directive to produce regions of memory holding
|
|
extended precision numbers, however they can be used as
|
|
immediate operands to floating-point instructions. Adding a
|
|
directive to create extended precision numbers would not be
|
|
hard, but it has not yet seemed necessary.
|
|
|
|
@node M68K-Directives
|
|
@section 680x0 Machine Directives
|
|
|
|
@cindex M680x0 directives
|
|
@cindex directives, M680x0
|
|
In order to be compatible with the Sun assembler the 680x0 assembler
|
|
understands the following directives.
|
|
|
|
@table @code
|
|
@item .data1
|
|
@cindex @code{data1} directive, M680x0
|
|
This directive is identical to a @code{.data 1} directive.
|
|
|
|
@item .data2
|
|
@cindex @code{data2} directive, M680x0
|
|
This directive is identical to a @code{.data 2} directive.
|
|
|
|
@item .even
|
|
@cindex @code{even} directive, M680x0
|
|
This directive is identical to a @code{.align 1} directive.
|
|
@c Is this true? does it work???
|
|
|
|
@item .skip
|
|
@cindex @code{skip} directive, M680x0
|
|
This directive is identical to a @code{.space} directive.
|
|
@end table
|
|
|
|
@need 2000
|
|
@node M68K-opcodes
|
|
@section Opcodes
|
|
|
|
@cindex M680x0 opcodes
|
|
@cindex opcodes, M680x0
|
|
@cindex instruction set, M680x0
|
|
@c pesch@cygnus.com: I don't see any point in the following
|
|
@c paragraph. Bugs are bugs; how does saying this
|
|
@c help anyone?
|
|
@ignore
|
|
Danger: Several bugs have been found in the opcode table (and
|
|
fixed). More bugs may exist. Be careful when using obscure
|
|
instructions.
|
|
@end ignore
|
|
|
|
@menu
|
|
* M68K-Branch:: Branch Improvement
|
|
* M68K-Chars:: Special Characters
|
|
@end menu
|
|
|
|
@node M68K-Branch
|
|
@subsection Branch Improvement
|
|
|
|
@cindex pseudo-opcodes, M680x0
|
|
@cindex M680x0 pseudo-opcodes
|
|
@cindex branch improvement, M680x0
|
|
@cindex M680x0 branch improvement
|
|
Certain pseudo opcodes are permitted for branch instructions.
|
|
They expand to the shortest branch instruction that reach the
|
|
target. Generally these mnemonics are made by substituting @samp{j} for
|
|
@samp{b} at the start of a Motorola mnemonic.
|
|
|
|
The following table summarizes the pseudo-operations. A @code{*} flags
|
|
cases that are more fully described after the table:
|
|
|
|
@smallexample
|
|
Displacement
|
|
+-------------------------------------------------
|
|
| 68020 68000/10
|
|
Pseudo-Op |BYTE WORD LONG LONG non-PC relative
|
|
+-------------------------------------------------
|
|
jbsr |bsrs bsr bsrl jsr jsr
|
|
jra |bras bra bral jmp jmp
|
|
* jXX |bXXs bXX bXXl bNXs;jmpl bNXs;jmp
|
|
* dbXX |dbXX dbXX dbXX; bra; jmpl
|
|
* fjXX |fbXXw fbXXw fbXXl fbNXw;jmp
|
|
|
|
XX: condition
|
|
NX: negative of condition XX
|
|
|
|
@end smallexample
|
|
@center @code{*}---see full description below
|
|
|
|
@table @code
|
|
@item jbsr
|
|
@itemx jra
|
|
These are the simplest jump pseudo-operations; they always map to one
|
|
particular machine instruction, depending on the displacement to the
|
|
branch target.
|
|
|
|
@item j@var{XX}
|
|
Here, @samp{j@var{XX}} stands for an entire family of pseudo-operations,
|
|
where @var{XX} is a conditional branch or condition-code test. The full
|
|
list of pseudo-ops in this family is:
|
|
@smallexample
|
|
jhi jls jcc jcs jne jeq jvc
|
|
jvs jpl jmi jge jlt jgt jle
|
|
@end smallexample
|
|
|
|
For the cases of non-PC relative displacements and long displacements on
|
|
the 68000 or 68010, @code{@value{AS}} issues a longer code fragment in terms of
|
|
@var{NX}, the opposite condition to @var{XX}. For example, for the
|
|
non-PC relative case:
|
|
@smallexample
|
|
j@var{XX} foo
|
|
@end smallexample
|
|
gives
|
|
@smallexample
|
|
b@var{NX}s oof
|
|
jmp foo
|
|
oof:
|
|
@end smallexample
|
|
|
|
@item db@var{XX}
|
|
The full family of pseudo-operations covered here is
|
|
@smallexample
|
|
dbhi dbls dbcc dbcs dbne dbeq dbvc
|
|
dbvs dbpl dbmi dbge dblt dbgt dble
|
|
dbf dbra dbt
|
|
@end smallexample
|
|
|
|
Other than for word and byte displacements, when the source reads
|
|
@samp{db@var{XX} foo}, @code{@value{AS}} emits
|
|
@smallexample
|
|
db@var{XX} oo1
|
|
bra oo2
|
|
oo1:jmpl foo
|
|
oo2:
|
|
@end smallexample
|
|
|
|
@item fj@var{XX}
|
|
This family includes
|
|
@smallexample
|
|
fjne fjeq fjge fjlt fjgt fjle fjf
|
|
fjt fjgl fjgle fjnge fjngl fjngle fjngt
|
|
fjnle fjnlt fjoge fjogl fjogt fjole fjolt
|
|
fjor fjseq fjsf fjsne fjst fjueq fjuge
|
|
fjugt fjule fjult fjun
|
|
@end smallexample
|
|
|
|
For branch targets that are not PC relative, @code{@value{AS}} emits
|
|
@smallexample
|
|
fb@var{NX} oof
|
|
jmp foo
|
|
oof:
|
|
@end smallexample
|
|
when it encounters @samp{fj@var{XX} foo}.
|
|
|
|
@end table
|
|
|
|
@node M68K-Chars
|
|
@subsection Special Characters
|
|
|
|
@cindex special characters, M680x0
|
|
@cindex M680x0 immediate character
|
|
@cindex immediate character, M680x0
|
|
@cindex M680x0 line comment character
|
|
@cindex line comment character, M680x0
|
|
@cindex comments, M680x0
|
|
The immediate character is @samp{#} for Sun compatibility. The
|
|
line-comment character is @samp{|}. If a @samp{#} appears at the
|
|
beginning of a line, it is treated as a comment unless it looks like
|
|
@samp{# line file}, in which case it is treated normally.
|
|
|
|
@end ifset
|
|
@ignore
|
|
@c FIXME! Stop ignoring when filled in.
|
|
@node 32x32
|
|
@chapter 32x32
|
|
|
|
@section Options
|
|
The 32x32 version of @code{@value{AS}} accepts a @samp{-m32032} option to
|
|
specify thiat it is compiling for a 32032 processor, or a
|
|
@samp{-m32532} to specify that it is compiling for a 32532 option.
|
|
The default (if neither is specified) is chosen when the assembler
|
|
is compiled.
|
|
|
|
@section Syntax
|
|
I don't know anything about the 32x32 syntax assembled by
|
|
@code{@value{AS}}. Someone who undersands the processor (I've never seen
|
|
one) and the possible syntaxes should write this section.
|
|
|
|
@section Floating Point
|
|
The 32x32 uses @sc{ieee} floating point numbers, but @code{@value{AS}}
|
|
only creates single or double precision values. I don't know if the
|
|
32x32 understands extended precision numbers.
|
|
|
|
@section 32x32 Machine Directives
|
|
The 32x32 has no machine dependent directives.
|
|
|
|
@end ignore
|
|
@ifset SPARC
|
|
@ifset GENERIC
|
|
@page
|
|
@node Sparc-Dependent
|
|
@chapter SPARC Dependent Features
|
|
@end ifset
|
|
@ifclear GENERIC
|
|
@node Machine Dependencies
|
|
@chapter SPARC Dependent Features
|
|
@end ifclear
|
|
|
|
@cindex SPARC support
|
|
@menu
|
|
* Sparc-Opts:: Options
|
|
* Sparc-Float:: Floating Point
|
|
* Sparc-Directives:: Sparc Machine Directives
|
|
@end menu
|
|
|
|
@node Sparc-Opts
|
|
@section Options
|
|
|
|
@cindex options for SPARC
|
|
@cindex SPARC options
|
|
@cindex architectures, SPARC
|
|
@cindex SPARC architectures
|
|
The SPARC chip family includes several successive levels (or other
|
|
variants) of chip, using the same core instruction set, but including
|
|
a few additional instructions at each level.
|
|
|
|
By default, @code{@value{AS}} assumes the core instruction set (SPARC
|
|
v6), but ``bumps'' the architecture level as needed: it switches to
|
|
successively higher architectures as it encounters instructions that
|
|
only exist in the higher levels.
|
|
|
|
@table @code
|
|
@item -Av6 | -Av7 | -Av8 | -Av9 | -Asparclite
|
|
@kindex -Av6
|
|
@kindex Av7
|
|
@kindex -Av8
|
|
@kindex -Av9
|
|
@kindex -Asparclite
|
|
Use one of the @samp{-A} options to select one of the SPARC
|
|
architectures explicitly. If you select an architecture explicitly,
|
|
@code{@value{AS}} reports a fatal error if it encounters an instruction
|
|
or feature requiring a higher level.
|
|
|
|
@item -bump
|
|
Permit the assembler to ``bump'' the architecture level as required, but
|
|
warn whenever it is necessary to switch to another level.
|
|
@end table
|
|
|
|
@ignore
|
|
@c FIXME: (sparc) Fill in "syntax" section!
|
|
@c subsection syntax
|
|
I don't know anything about Sparc syntax. Someone who does
|
|
will have to write this section.
|
|
@end ignore
|
|
|
|
@node Sparc-Float
|
|
@section Floating Point
|
|
|
|
@cindex floating point, SPARC (@sc{ieee})
|
|
@cindex SPARC floating point (@sc{ieee})
|
|
The Sparc uses @sc{ieee} floating-point numbers.
|
|
|
|
@node Sparc-Directives
|
|
@section Sparc Machine Directives
|
|
|
|
@cindex SPARC machine directives
|
|
@cindex machine directives, SPARC
|
|
The Sparc version of @code{@value{AS}} supports the following additional
|
|
machine directives:
|
|
|
|
@table @code
|
|
@item .align
|
|
@cindex @code{align} directive, SPARC
|
|
This must be followed by the desired alignment in bytes.
|
|
|
|
@item .common
|
|
@cindex @code{common} directive, SPARC
|
|
This must be followed by a symbol name, a positive number, and
|
|
@code{"bss"}. This behaves somewhat like @code{.comm}, but the
|
|
syntax is different.
|
|
|
|
@item .half
|
|
@cindex @code{half} directive, SPARC
|
|
This is functionally identical to @code{.short}.
|
|
|
|
@item .proc
|
|
@cindex @code{proc} directive, SPARC
|
|
This directive is ignored. Any text following it on the same
|
|
line is also ignored.
|
|
|
|
@item .reserve
|
|
@cindex @code{reserve} directive, SPARC
|
|
This must be followed by a symbol name, a positive number, and
|
|
@code{"bss"}. This behaves somewhat like @code{.lcomm}, but the
|
|
syntax is different.
|
|
|
|
@item .seg
|
|
@cindex @code{seg} directive, SPARC
|
|
This must be followed by @code{"text"}, @code{"data"}, or
|
|
@code{"data1"}. It behaves like @code{.text}, @code{.data}, or
|
|
@code{.data 1}.
|
|
|
|
@item .skip
|
|
@cindex @code{skip} directive, SPARC
|
|
This is functionally identical to the @code{.space} directive.
|
|
|
|
@item .word
|
|
@cindex @code{word} directive, SPARC
|
|
On the Sparc, the @code{.word} directive produces 32 bit values,
|
|
instead of the 16 bit values it produces on many other machines.
|
|
|
|
@item .xword
|
|
@cindex @code{xword} directive, SPARC
|
|
On the Sparc V9 processor, the @code{.xword} directive produces
|
|
64 bit values.
|
|
@end table
|
|
|
|
@end ifset
|
|
@ifset I80386
|
|
@ifset GENERIC
|
|
@page
|
|
@node i386-Dependent
|
|
@chapter 80386 Dependent Features
|
|
@end ifset
|
|
@ifclear GENERIC
|
|
@node Machine Dependencies
|
|
@chapter 80386 Dependent Features
|
|
@end ifclear
|
|
|
|
@cindex i386 support
|
|
@cindex i80306 support
|
|
@menu
|
|
* i386-Options:: Options
|
|
* i386-Syntax:: AT&T Syntax versus Intel Syntax
|
|
* i386-Opcodes:: Opcode Naming
|
|
* i386-Regs:: Register Naming
|
|
* i386-prefixes:: Opcode Prefixes
|
|
* i386-Memory:: Memory References
|
|
* i386-jumps:: Handling of Jump Instructions
|
|
* i386-Float:: Floating Point
|
|
* i386-16bit:: Writing 16-bit Code
|
|
* i386-Notes:: Notes
|
|
@end menu
|
|
|
|
@node i386-Options
|
|
@section Options
|
|
|
|
@cindex options for i386 (none)
|
|
@cindex i386 options (none)
|
|
The 80386 has no machine dependent options.
|
|
|
|
@node i386-Syntax
|
|
@section AT&T Syntax versus Intel Syntax
|
|
|
|
@cindex i386 syntax compatibility
|
|
@cindex syntax compatibility, i386
|
|
In order to maintain compatibility with the output of @code{@value{GCC}},
|
|
@code{@value{AS}} supports AT&T System V/386 assembler syntax. This is quite
|
|
different from Intel syntax. We mention these differences because
|
|
almost all 80386 documents used only Intel syntax. Notable differences
|
|
between the two syntaxes are:
|
|
|
|
@itemize @bullet
|
|
@item
|
|
@cindex immediate operands, i386
|
|
@cindex i386 immediate operands
|
|
@cindex register operands, i386
|
|
@cindex i386 register operands
|
|
@cindex jump/call operands, i386
|
|
@cindex i386 jump/call operands
|
|
@cindex operand delimiters, i386
|
|
AT&T immediate operands are preceded by @samp{$}; Intel immediate
|
|
operands are undelimited (Intel @samp{push 4} is AT&T @samp{pushl $4}).
|
|
AT&T register operands are preceded by @samp{%}; Intel register operands
|
|
are undelimited. AT&T absolute (as opposed to PC relative) jump/call
|
|
operands are prefixed by @samp{*}; they are undelimited in Intel syntax.
|
|
|
|
@item
|
|
@cindex i386 source, destination operands
|
|
@cindex source, destination operands; i386
|
|
AT&T and Intel syntax use the opposite order for source and destination
|
|
operands. Intel @samp{add eax, 4} is @samp{addl $4, %eax}. The
|
|
@samp{source, dest} convention is maintained for compatibility with
|
|
previous Unix assemblers.
|
|
|
|
@item
|
|
@cindex opcode suffixes, i386
|
|
@cindex sizes operands, i386
|
|
@cindex i386 size suffixes
|
|
In AT&T syntax the size of memory operands is determined from the last
|
|
character of the opcode name. Opcode suffixes of @samp{b}, @samp{w},
|
|
and @samp{l} specify byte (8-bit), word (16-bit), and long (32-bit)
|
|
memory references. Intel syntax accomplishes this by prefixes memory
|
|
operands (@emph{not} the opcodes themselves) with @samp{byte ptr},
|
|
@samp{word ptr}, and @samp{dword ptr}. Thus, Intel @samp{mov al, byte
|
|
ptr @var{foo}} is @samp{movb @var{foo}, %al} in AT&T syntax.
|
|
|
|
@item
|
|
@cindex return instructions, i386
|
|
@cindex i386 jump, call, return
|
|
Immediate form long jumps and calls are
|
|
@samp{lcall/ljmp $@var{section}, $@var{offset}} in AT&T syntax; the
|
|
Intel syntax is
|
|
@samp{call/jmp far @var{section}:@var{offset}}. Also, the far return
|
|
instruction
|
|
is @samp{lret $@var{stack-adjust}} in AT&T syntax; Intel syntax is
|
|
@samp{ret far @var{stack-adjust}}.
|
|
|
|
@item
|
|
@cindex sections, i386
|
|
@cindex i386 sections
|
|
The AT&T assembler does not provide support for multiple section
|
|
programs. Unix style systems expect all programs to be single sections.
|
|
@end itemize
|
|
|
|
@node i386-Opcodes
|
|
@section Opcode Naming
|
|
|
|
@cindex i386 opcode naming
|
|
@cindex opcode naming, i386
|
|
Opcode names are suffixed with one character modifiers which specify the
|
|
size of operands. The letters @samp{b}, @samp{w}, and @samp{l} specify
|
|
byte, word, and long operands. If no suffix is specified by an
|
|
instruction and it contains no memory operands then @code{@value{AS}} tries to
|
|
fill in the missing suffix based on the destination register operand
|
|
(the last one by convention). Thus, @samp{mov %ax, %bx} is equivalent
|
|
to @samp{movw %ax, %bx}; also, @samp{mov $1, %bx} is equivalent to
|
|
@samp{movw $1, %bx}. Note that this is incompatible with the AT&T Unix
|
|
assembler which assumes that a missing opcode suffix implies long
|
|
operand size. (This incompatibility does not affect compiler output
|
|
since compilers always explicitly specify the opcode suffix.)
|
|
|
|
Almost all opcodes have the same names in AT&T and Intel format. There
|
|
are a few exceptions. The sign extend and zero extend instructions need
|
|
two sizes to specify them. They need a size to sign/zero extend
|
|
@emph{from} and a size to zero extend @emph{to}. This is accomplished
|
|
by using two opcode suffixes in AT&T syntax. Base names for sign extend
|
|
and zero extend are @samp{movs@dots{}} and @samp{movz@dots{}} in AT&T
|
|
syntax (@samp{movsx} and @samp{movzx} in Intel syntax). The opcode
|
|
suffixes are tacked on to this base name, the @emph{from} suffix before
|
|
the @emph{to} suffix. Thus, @samp{movsbl %al, %edx} is AT&T syntax for
|
|
``move sign extend @emph{from} %al @emph{to} %edx.'' Possible suffixes,
|
|
thus, are @samp{bl} (from byte to long), @samp{bw} (from byte to word),
|
|
and @samp{wl} (from word to long).
|
|
|
|
@cindex conversion instructions, i386
|
|
@cindex i386 conversion instructions
|
|
The Intel-syntax conversion instructions
|
|
|
|
@itemize @bullet
|
|
@item
|
|
@samp{cbw} --- sign-extend byte in @samp{%al} to word in @samp{%ax},
|
|
|
|
@item
|
|
@samp{cwde} --- sign-extend word in @samp{%ax} to long in @samp{%eax},
|
|
|
|
@item
|
|
@samp{cwd} --- sign-extend word in @samp{%ax} to long in @samp{%dx:%ax},
|
|
|
|
@item
|
|
@samp{cdq} --- sign-extend dword in @samp{%eax} to quad in @samp{%edx:%eax},
|
|
@end itemize
|
|
|
|
@noindent
|
|
are called @samp{cbtw}, @samp{cwtl}, @samp{cwtd}, and @samp{cltd} in
|
|
AT&T naming. @code{@value{AS}} accepts either naming for these instructions.
|
|
|
|
@cindex jump instructions, i386
|
|
@cindex call instructions, i386
|
|
Far call/jump instructions are @samp{lcall} and @samp{ljmp} in
|
|
AT&T syntax, but are @samp{call far} and @samp{jump far} in Intel
|
|
convention.
|
|
|
|
@node i386-Regs
|
|
@section Register Naming
|
|
|
|
@cindex i386 registers
|
|
@cindex registers, i386
|
|
Register operands are always prefixes with @samp{%}. The 80386 registers
|
|
consist of
|
|
|
|
@itemize @bullet
|
|
@item
|
|
the 8 32-bit registers @samp{%eax} (the accumulator), @samp{%ebx},
|
|
@samp{%ecx}, @samp{%edx}, @samp{%edi}, @samp{%esi}, @samp{%ebp} (the
|
|
frame pointer), and @samp{%esp} (the stack pointer).
|
|
|
|
@item
|
|
the 8 16-bit low-ends of these: @samp{%ax}, @samp{%bx}, @samp{%cx},
|
|
@samp{%dx}, @samp{%di}, @samp{%si}, @samp{%bp}, and @samp{%sp}.
|
|
|
|
@item
|
|
the 8 8-bit registers: @samp{%ah}, @samp{%al}, @samp{%bh},
|
|
@samp{%bl}, @samp{%ch}, @samp{%cl}, @samp{%dh}, and @samp{%dl} (These
|
|
are the high-bytes and low-bytes of @samp{%ax}, @samp{%bx},
|
|
@samp{%cx}, and @samp{%dx})
|
|
|
|
@item
|
|
the 6 section registers @samp{%cs} (code section), @samp{%ds}
|
|
(data section), @samp{%ss} (stack section), @samp{%es}, @samp{%fs},
|
|
and @samp{%gs}.
|
|
|
|
@item
|
|
the 3 processor control registers @samp{%cr0}, @samp{%cr2}, and
|
|
@samp{%cr3}.
|
|
|
|
@item
|
|
the 6 debug registers @samp{%db0}, @samp{%db1}, @samp{%db2},
|
|
@samp{%db3}, @samp{%db6}, and @samp{%db7}.
|
|
|
|
@item
|
|
the 2 test registers @samp{%tr6} and @samp{%tr7}.
|
|
|
|
@item
|
|
the 8 floating point register stack @samp{%st} or equivalently
|
|
@samp{%st(0)}, @samp{%st(1)}, @samp{%st(2)}, @samp{%st(3)},
|
|
@samp{%st(4)}, @samp{%st(5)}, @samp{%st(6)}, and @samp{%st(7)}.
|
|
@end itemize
|
|
|
|
@node i386-prefixes
|
|
@section Opcode Prefixes
|
|
|
|
@cindex i386 opcode prefixes
|
|
@cindex opcode prefixes, i386
|
|
@cindex prefixes, i386
|
|
Opcode prefixes are used to modify the following opcode. They are used
|
|
to repeat string instructions, to provide section overrides, to perform
|
|
bus lock operations, and to give operand and address size (16-bit
|
|
operands are specified in an instruction by prefixing what would
|
|
normally be 32-bit operands with a ``operand size'' opcode prefix).
|
|
Opcode prefixes are usually given as single-line instructions with no
|
|
operands, and must directly precede the instruction they act upon. For
|
|
example, the @samp{scas} (scan string) instruction is repeated with:
|
|
@smallexample
|
|
repne
|
|
scas
|
|
@end smallexample
|
|
|
|
Here is a list of opcode prefixes:
|
|
|
|
@itemize @bullet
|
|
@item
|
|
@cindex section override prefixes, i386
|
|
Section override prefixes @samp{cs}, @samp{ds}, @samp{ss}, @samp{es},
|
|
@samp{fs}, @samp{gs}. These are automatically added by specifying
|
|
using the @var{section}:@var{memory-operand} form for memory references.
|
|
|
|
@item
|
|
@cindex size prefixes, i386
|
|
Operand/Address size prefixes @samp{data16} and @samp{addr16}
|
|
change 32-bit operands/addresses into 16-bit operands/addresses. Note
|
|
that 16-bit addressing modes (i.e. 8086 and 80286 addressing modes)
|
|
are not supported (yet).
|
|
|
|
@item
|
|
@cindex bus lock prefixes, i386
|
|
@cindex inhibiting interrupts, i386
|
|
The bus lock prefix @samp{lock} inhibits interrupts during
|
|
execution of the instruction it precedes. (This is only valid with
|
|
certain instructions; see a 80386 manual for details).
|
|
|
|
@item
|
|
@cindex coprocessor wait, i386
|
|
The wait for coprocessor prefix @samp{wait} waits for the
|
|
coprocessor to complete the current instruction. This should never be
|
|
needed for the 80386/80387 combination.
|
|
|
|
@item
|
|
@cindex repeat prefixes, i386
|
|
The @samp{rep}, @samp{repe}, and @samp{repne} prefixes are added
|
|
to string instructions to make them repeat @samp{%ecx} times.
|
|
@end itemize
|
|
|
|
@node i386-Memory
|
|
@section Memory References
|
|
|
|
@cindex i386 memory references
|
|
@cindex memory references, i386
|
|
An Intel syntax indirect memory reference of the form
|
|
|
|
@smallexample
|
|
@var{section}:[@var{base} + @var{index}*@var{scale} + @var{disp}]
|
|
@end smallexample
|
|
|
|
@noindent
|
|
is translated into the AT&T syntax
|
|
|
|
@smallexample
|
|
@var{section}:@var{disp}(@var{base}, @var{index}, @var{scale})
|
|
@end smallexample
|
|
|
|
@noindent
|
|
where @var{base} and @var{index} are the optional 32-bit base and
|
|
index registers, @var{disp} is the optional displacement, and
|
|
@var{scale}, taking the values 1, 2, 4, and 8, multiplies @var{index}
|
|
to calculate the address of the operand. If no @var{scale} is
|
|
specified, @var{scale} is taken to be 1. @var{section} specifies the
|
|
optional section register for the memory operand, and may override the
|
|
default section register (see a 80386 manual for section register
|
|
defaults). Note that section overrides in AT&T syntax @emph{must} have
|
|
be preceded by a @samp{%}. If you specify a section override which
|
|
coincides with the default section register, @code{@value{AS}} does @emph{not}
|
|
output any section register override prefixes to assemble the given
|
|
instruction. Thus, section overrides can be specified to emphasize which
|
|
section register is used for a given memory operand.
|
|
|
|
Here are some examples of Intel and AT&T style memory references:
|
|
|
|
@table @asis
|
|
@item AT&T: @samp{-4(%ebp)}, Intel: @samp{[ebp - 4]}
|
|
@var{base} is @samp{%ebp}; @var{disp} is @samp{-4}. @var{section} is
|
|
missing, and the default section is used (@samp{%ss} for addressing with
|
|
@samp{%ebp} as the base register). @var{index}, @var{scale} are both missing.
|
|
|
|
@item AT&T: @samp{foo(,%eax,4)}, Intel: @samp{[foo + eax*4]}
|
|
@var{index} is @samp{%eax} (scaled by a @var{scale} 4); @var{disp} is
|
|
@samp{foo}. All other fields are missing. The section register here
|
|
defaults to @samp{%ds}.
|
|
|
|
@item AT&T: @samp{foo(,1)}; Intel @samp{[foo]}
|
|
This uses the value pointed to by @samp{foo} as a memory operand.
|
|
Note that @var{base} and @var{index} are both missing, but there is only
|
|
@emph{one} @samp{,}. This is a syntactic exception.
|
|
|
|
@item AT&T: @samp{%gs:foo}; Intel @samp{gs:foo}
|
|
This selects the contents of the variable @samp{foo} with section
|
|
register @var{section} being @samp{%gs}.
|
|
@end table
|
|
|
|
Absolute (as opposed to PC relative) call and jump operands must be
|
|
prefixed with @samp{*}. If no @samp{*} is specified, @code{@value{AS}}
|
|
always chooses PC relative addressing for jump/call labels.
|
|
|
|
Any instruction that has a memory operand @emph{must} specify its size (byte,
|
|
word, or long) with an opcode suffix (@samp{b}, @samp{w}, or @samp{l},
|
|
respectively).
|
|
|
|
@node i386-jumps
|
|
@section Handling of Jump Instructions
|
|
|
|
@cindex jump optimization, i386
|
|
@cindex i386 jump optimization
|
|
Jump instructions are always optimized to use the smallest possible
|
|
displacements. This is accomplished by using byte (8-bit) displacement
|
|
jumps whenever the target is sufficiently close. If a byte displacement
|
|
is insufficient a long (32-bit) displacement is used. We do not support
|
|
word (16-bit) displacement jumps (i.e. prefixing the jump instruction
|
|
with the @samp{addr16} opcode prefix), since the 80386 insists upon masking
|
|
@samp{%eip} to 16 bits after the word displacement is added.
|
|
|
|
Note that the @samp{jcxz}, @samp{jecxz}, @samp{loop}, @samp{loopz},
|
|
@samp{loope}, @samp{loopnz} and @samp{loopne} instructions only come in byte
|
|
displacements, so that if you use these instructions (@code{@value{GCC}} does
|
|
not use them) you may get an error message (and incorrect code). The AT&T
|
|
80386 assembler tries to get around this problem by expanding @samp{jcxz foo}
|
|
to
|
|
|
|
@smallexample
|
|
jcxz cx_zero
|
|
jmp cx_nonzero
|
|
cx_zero: jmp foo
|
|
cx_nonzero:
|
|
@end smallexample
|
|
|
|
@node i386-Float
|
|
@section Floating Point
|
|
|
|
@cindex i386 floating point
|
|
@cindex floating point, i386
|
|
All 80387 floating point types except packed BCD are supported.
|
|
(BCD support may be added without much difficulty). These data
|
|
types are 16-, 32-, and 64- bit integers, and single (32-bit),
|
|
double (64-bit), and extended (80-bit) precision floating point.
|
|
Each supported type has an opcode suffix and a constructor
|
|
associated with it. Opcode suffixes specify operand's data
|
|
types. Constructors build these data types into memory.
|
|
|
|
@itemize @bullet
|
|
@item
|
|
@cindex @code{float} directive, i386
|
|
@cindex @code{single} directive, i386
|
|
@cindex @code{double} directive, i386
|
|
@cindex @code{tfloat} directive, i386
|
|
Floating point constructors are @samp{.float} or @samp{.single},
|
|
@samp{.double}, and @samp{.tfloat} for 32-, 64-, and 80-bit formats.
|
|
These correspond to opcode suffixes @samp{s}, @samp{l}, and @samp{t}.
|
|
@samp{t} stands for temporary real, and that the 80387 only supports
|
|
this format via the @samp{fldt} (load temporary real to stack top) and
|
|
@samp{fstpt} (store temporary real and pop stack) instructions.
|
|
|
|
@item
|
|
@cindex @code{word} directive, i386
|
|
@cindex @code{long} directive, i386
|
|
@cindex @code{int} directive, i386
|
|
@cindex @code{quad} directive, i386
|
|
Integer constructors are @samp{.word}, @samp{.long} or @samp{.int}, and
|
|
@samp{.quad} for the 16-, 32-, and 64-bit integer formats. The corresponding
|
|
opcode suffixes are @samp{s} (single), @samp{l} (long), and @samp{q}
|
|
(quad). As with the temporary real format the 64-bit @samp{q} format is
|
|
only present in the @samp{fildq} (load quad integer to stack top) and
|
|
@samp{fistpq} (store quad integer and pop stack) instructions.
|
|
@end itemize
|
|
|
|
Register to register operations do not require opcode suffixes,
|
|
so that @samp{fst %st, %st(1)} is equivalent to @samp{fstl %st, %st(1)}.
|
|
|
|
@cindex i386 @code{fwait} instruction
|
|
@cindex @code{fwait instruction}, i386
|
|
Since the 80387 automatically synchronizes with the 80386 @samp{fwait}
|
|
instructions are almost never needed (this is not the case for the
|
|
80286/80287 and 8086/8087 combinations). Therefore, @code{@value{AS}} suppresses
|
|
the @samp{fwait} instruction whenever it is implicitly selected by one
|
|
of the @samp{fn@dots{}} instructions. For example, @samp{fsave} and
|
|
@samp{fnsave} are treated identically. In general, all the @samp{fn@dots{}}
|
|
instructions are made equivalent to @samp{f@dots{}} instructions. If
|
|
@samp{fwait} is desired it must be explicitly coded.
|
|
|
|
@node i386-16bit
|
|
@section Writing 16-bit Code
|
|
|
|
@cindex i386 16-bit code
|
|
@cindex 16-bit code, i386
|
|
@cindex real-mode code, i386
|
|
@cindex @code{code16} directive, i386
|
|
@cindex @code{code32} directive, i386
|
|
While GAS normally writes only ``pure'' 32-bit i386 code, it has limited
|
|
support for writing code to run in real mode or in 16-bit protected mode
|
|
code segments. To do this, insert a @samp{.code16} directive before the
|
|
assembly language instructions to be run in 16-bit mode. You can switch
|
|
GAS back to writing normal 32-bit code with the @samp{.code32} directive.
|
|
|
|
GAS understands exactly the same assembly language syntax in 16-bit mode as
|
|
in 32-bit mode. The function of any given instruction is exactly the same
|
|
regardless of mode, as long as the resulting object code is executed in the
|
|
mode for which GAS wrote it. So, for example, the @samp{ret} mnemonic
|
|
produces a 32-bit return instruction regardless of whether it is to be run
|
|
in 16-bit or 32-bit mode. (If GAS is in 16-bit mode, it will add an
|
|
operand size prefix to the instruction to force it to be a 32-bit return.)
|
|
|
|
This means, for one thing, that you can use GNU CC to write code to be run
|
|
in real mode or 16-bit protected mode. Just insert the statement
|
|
@samp{asm(".code16");} at the beginning of your C source file, and while
|
|
GNU CC will still be generating 32-bit code, GAS will automatically add all
|
|
the necessary size prefixes to make that code run in 16-bit mode. Of
|
|
course, since GNU CC only writes small-model code (it doesn't know how to
|
|
attach segment selectors to pointers like native x86 compilers do), any
|
|
16-bit code you write with GNU CC will essentially be limited to a 64K
|
|
address space. Also, there will be a code size and performance penalty
|
|
due to all the extra address and operand size prefixes GAS has to add to
|
|
the instructions.
|
|
|
|
Note that placing GAS in 16-bit mode does not mean that the resulting
|
|
code will necessarily run on a 16-bit pre-80386 processor. To write code
|
|
that runs on such a processor, you would have to refrain from using
|
|
@emph{any} 32-bit constructs which require GAS to output address or
|
|
operand size prefixes. At the moment this would be rather difficult,
|
|
because GAS currently supports @emph{only} 32-bit addressing modes: when
|
|
writing 16-bit code, it @emph{always} outputs address size prefixes for any
|
|
instruction that uses a non-register addressing mode. So you can write
|
|
code that runs on 16-bit processors, but only if that code never references
|
|
memory.
|
|
|
|
@node i386-Notes
|
|
@section Notes
|
|
|
|
@cindex i386 @code{mul}, @code{imul} instructions
|
|
@cindex @code{mul} instruction, i386
|
|
@cindex @code{imul} instruction, i386
|
|
There is some trickery concerning the @samp{mul} and @samp{imul}
|
|
instructions that deserves mention. The 16-, 32-, and 64-bit expanding
|
|
multiplies (base opcode @samp{0xf6}; extension 4 for @samp{mul} and 5
|
|
for @samp{imul}) can be output only in the one operand form. Thus,
|
|
@samp{imul %ebx, %eax} does @emph{not} select the expanding multiply;
|
|
the expanding multiply would clobber the @samp{%edx} register, and this
|
|
would confuse @code{@value{GCC}} output. Use @samp{imul %ebx} to get the
|
|
64-bit product in @samp{%edx:%eax}.
|
|
|
|
We have added a two operand form of @samp{imul} when the first operand
|
|
is an immediate mode expression and the second operand is a register.
|
|
This is just a shorthand, so that, multiplying @samp{%eax} by 69, for
|
|
example, can be done with @samp{imul $69, %eax} rather than @samp{imul
|
|
$69, %eax, %eax}.
|
|
|
|
@end ifset
|
|
@ifset Z8000
|
|
@ifset GENERIC
|
|
@page
|
|
@node Z8000-Dependent
|
|
@chapter Z8000 Dependent Features
|
|
@end ifset
|
|
@ifclear GENERIC
|
|
@node Machine Dependencies
|
|
@chapter Z8000 Dependent Features
|
|
@end ifclear
|
|
|
|
@cindex Z8000 support
|
|
The Z8000 @value{AS} supports both members of the Z8000 family: the
|
|
unsegmented Z8002, with 16 bit addresses, and the segmented Z8001 with
|
|
24 bit addresses.
|
|
|
|
When the assembler is in unsegmented mode (specified with the
|
|
@code{unsegm} directive), an address takes up one word (16 bit)
|
|
sized register. When the assembler is in segmented mode (specified with
|
|
the @code{segm} directive), a 24-bit address takes up a long (32 bit)
|
|
register. @xref{Z8000 Directives,,Assembler Directives for the Z8000},
|
|
for a list of other Z8000 specific assembler directives.
|
|
|
|
@menu
|
|
* Z8000 Options:: No special command-line options for Z8000
|
|
* Z8000 Syntax:: Assembler syntax for the Z8000
|
|
* Z8000 Directives:: Special directives for the Z8000
|
|
* Z8000 Opcodes:: Opcodes
|
|
@end menu
|
|
|
|
@node Z8000 Options
|
|
@section Options
|
|
|
|
@cindex Z8000 options
|
|
@cindex options, Z8000
|
|
@code{@value{AS}} has no additional command-line options for the Zilog
|
|
Z8000 family.
|
|
|
|
@node Z8000 Syntax
|
|
@section Syntax
|
|
@menu
|
|
* Z8000-Chars:: Special Characters
|
|
* Z8000-Regs:: Register Names
|
|
* Z8000-Addressing:: Addressing Modes
|
|
@end menu
|
|
|
|
@node Z8000-Chars
|
|
@subsection Special Characters
|
|
|
|
@cindex line comment character, Z8000
|
|
@cindex Z8000 line comment character
|
|
@samp{!} is the line comment character.
|
|
|
|
@cindex line separator, Z8000
|
|
@cindex statement separator, Z8000
|
|
@cindex Z8000 line separator
|
|
You can use @samp{;} instead of a newline to separate statements.
|
|
|
|
@node Z8000-Regs
|
|
@subsection Register Names
|
|
|
|
@cindex Z8000 registers
|
|
@cindex registers, Z8000
|
|
The Z8000 has sixteen 16 bit registers, numbered 0 to 15. You can refer
|
|
to different sized groups of registers by register number, with the
|
|
prefix @samp{r} for 16 bit registers, @samp{rr} for 32 bit registers and
|
|
@samp{rq} for 64 bit registers. You can also refer to the contents of
|
|
the first eight (of the sixteen 16 bit registers) by bytes. They are
|
|
named @samp{r@var{n}h} and @samp{r@var{n}l}.
|
|
|
|
@smallexample
|
|
@exdent @emph{byte registers}
|
|
r0l r0h r1h r1l r2h r2l r3h r3l
|
|
r4h r4l r5h r5l r6h r6l r7h r7l
|
|
|
|
@exdent @emph{word registers}
|
|
r0 r1 r2 r3 r4 r5 r6 r7 r8 r9 r10 r11 r12 r13 r14 r15
|
|
|
|
@exdent @emph{long word registers}
|
|
rr0 rr2 rr4 rr6 rr8 rr10 rr12 rr14
|
|
|
|
@exdent @emph{quad word registers}
|
|
rq0 rq4 rq8 rq12
|
|
@end smallexample
|
|
|
|
@node Z8000-Addressing
|
|
@subsection Addressing Modes
|
|
|
|
@cindex addressing modes, Z8000
|
|
@cindex Z800 addressing modes
|
|
@value{AS} understands the following addressing modes for the Z8000:
|
|
|
|
@table @code
|
|
@item r@var{n}
|
|
Register direct
|
|
|
|
@item @@r@var{n}
|
|
Indirect register
|
|
|
|
@item @var{addr}
|
|
Direct: the 16 bit or 24 bit address (depending on whether the assembler
|
|
is in segmented or unsegmented mode) of the operand is in the instruction.
|
|
|
|
@item address(r@var{n})
|
|
Indexed: the 16 or 24 bit address is added to the 16 bit register to produce
|
|
the final address in memory of the operand.
|
|
|
|
@item r@var{n}(#@var{imm})
|
|
Base Address: the 16 or 24 bit register is added to the 16 bit sign
|
|
extended immediate displacement to produce the final address in memory
|
|
of the operand.
|
|
|
|
@item r@var{n}(r@var{m})
|
|
Base Index: the 16 or 24 bit register r@var{n} is added to the sign
|
|
extended 16 bit index register r@var{m} to produce the final address in
|
|
memory of the operand.
|
|
|
|
@item #@var{xx}
|
|
Immediate data @var{xx}.
|
|
@end table
|
|
|
|
@node Z8000 Directives
|
|
@section Assembler Directives for the Z8000
|
|
|
|
@cindex Z8000 directives
|
|
@cindex directives, Z8000
|
|
The Z8000 port of @value{AS} includes these additional assembler directives,
|
|
for compatibility with other Z8000 assemblers. As shown, these do not
|
|
begin with @samp{.} (unlike the ordinary @value{AS} directives).
|
|
|
|
@table @code
|
|
@item segm
|
|
@kindex segm
|
|
Generates code for the segmented Z8001.
|
|
|
|
@item unsegm
|
|
@kindex unsegm
|
|
Generates code for the unsegmented Z8002.
|
|
|
|
@item name
|
|
@kindex name
|
|
Synonym for @code{.file}
|
|
|
|
@item global
|
|
@kindex global
|
|
Synonum for @code{.global}
|
|
|
|
@item wval
|
|
@kindex wval
|
|
Synonym for @code{.word}
|
|
|
|
@item lval
|
|
@kindex lval
|
|
Synonym for @code{.long}
|
|
|
|
@item bval
|
|
@kindex bval
|
|
Synonym for @code{.byte}
|
|
|
|
@item sval
|
|
@kindex sval
|
|
Assemble a string. @code{sval} expects one string literal, delimited by
|
|
single quotes. It assembles each byte of the string into consecutive
|
|
addresses. You can use the escape sequence @samp{%@var{xx}} (where
|
|
@var{xx} represents a two-digit hexadecimal number) to represent the
|
|
character whose @sc{ascii} value is @var{xx}. Use this feature to
|
|
describe single quote and other characters that may not appear in string
|
|
literals as themselves. For example, the C statement @w{@samp{char *a =
|
|
"he said \"it's 50% off\"";}} is represented in Z8000 assembly language
|
|
(shown with the assembler output in hex at the left) as
|
|
|
|
@iftex
|
|
@begingroup
|
|
@let@nonarrowing=@comment
|
|
@end iftex
|
|
@smallexample
|
|
68652073 sval 'he said %22it%27s 50%25 off%22%00'
|
|
61696420
|
|
22697427
|
|
73203530
|
|
25206F66
|
|
662200
|
|
@end smallexample
|
|
@iftex
|
|
@endgroup
|
|
@end iftex
|
|
|
|
@item rsect
|
|
@kindex rsect
|
|
synonym for @code{.section}
|
|
|
|
@item block
|
|
@kindex block
|
|
synonym for @code{.space}
|
|
|
|
@item even
|
|
@kindex even
|
|
synonym for @code{.align 1}
|
|
@end table
|
|
|
|
@node Z8000 Opcodes
|
|
@section Opcodes
|
|
|
|
@cindex Z8000 opcode summary
|
|
@cindex opcode summary, Z8000
|
|
@cindex mnemonics, Z8000
|
|
@cindex instruction summary, Z8000
|
|
For detailed information on the Z8000 machine instruction set, see
|
|
@cite{Z8000 Technical Manual}.
|
|
|
|
@ifset SMALL
|
|
@c this table, due to the multi-col faking and hardcoded order, looks silly
|
|
@c except in smallbook. See comments below "@set SMALL" near top of this file.
|
|
|
|
The following table summarizes the opcodes and their arguments:
|
|
@iftex
|
|
@begingroup
|
|
@let@nonarrowing=@comment
|
|
@end iftex
|
|
@smallexample
|
|
|
|
rs @r{16 bit source register}
|
|
rd @r{16 bit destination register}
|
|
rbs @r{8 bit source register}
|
|
rbd @r{8 bit destination register}
|
|
rrs @r{32 bit source register}
|
|
rrd @r{32 bit destination register}
|
|
rqs @r{64 bit source register}
|
|
rqd @r{64 bit destination register}
|
|
addr @r{16/24 bit address}
|
|
imm @r{immediate data}
|
|
|
|
adc rd,rs clrb addr cpsir @@rd,@@rs,rr,cc
|
|
adcb rbd,rbs clrb addr(rd) cpsirb @@rd,@@rs,rr,cc
|
|
add rd,@@rs clrb rbd dab rbd
|
|
add rd,addr com @@rd dbjnz rbd,disp7
|
|
add rd,addr(rs) com addr dec @@rd,imm4m1
|
|
add rd,imm16 com addr(rd) dec addr(rd),imm4m1
|
|
add rd,rs com rd dec addr,imm4m1
|
|
addb rbd,@@rs comb @@rd dec rd,imm4m1
|
|
addb rbd,addr comb addr decb @@rd,imm4m1
|
|
addb rbd,addr(rs) comb addr(rd) decb addr(rd),imm4m1
|
|
addb rbd,imm8 comb rbd decb addr,imm4m1
|
|
addb rbd,rbs comflg flags decb rbd,imm4m1
|
|
addl rrd,@@rs cp @@rd,imm16 di i2
|
|
addl rrd,addr cp addr(rd),imm16 div rrd,@@rs
|
|
addl rrd,addr(rs) cp addr,imm16 div rrd,addr
|
|
addl rrd,imm32 cp rd,@@rs div rrd,addr(rs)
|
|
addl rrd,rrs cp rd,addr div rrd,imm16
|
|
and rd,@@rs cp rd,addr(rs) div rrd,rs
|
|
and rd,addr cp rd,imm16 divl rqd,@@rs
|
|
and rd,addr(rs) cp rd,rs divl rqd,addr
|
|
and rd,imm16 cpb @@rd,imm8 divl rqd,addr(rs)
|
|
and rd,rs cpb addr(rd),imm8 divl rqd,imm32
|
|
andb rbd,@@rs cpb addr,imm8 divl rqd,rrs
|
|
andb rbd,addr cpb rbd,@@rs djnz rd,disp7
|
|
andb rbd,addr(rs) cpb rbd,addr ei i2
|
|
andb rbd,imm8 cpb rbd,addr(rs) ex rd,@@rs
|
|
andb rbd,rbs cpb rbd,imm8 ex rd,addr
|
|
bit @@rd,imm4 cpb rbd,rbs ex rd,addr(rs)
|
|
bit addr(rd),imm4 cpd rd,@@rs,rr,cc ex rd,rs
|
|
bit addr,imm4 cpdb rbd,@@rs,rr,cc exb rbd,@@rs
|
|
bit rd,imm4 cpdr rd,@@rs,rr,cc exb rbd,addr
|
|
bit rd,rs cpdrb rbd,@@rs,rr,cc exb rbd,addr(rs)
|
|
bitb @@rd,imm4 cpi rd,@@rs,rr,cc exb rbd,rbs
|
|
bitb addr(rd),imm4 cpib rbd,@@rs,rr,cc ext0e imm8
|
|
bitb addr,imm4 cpir rd,@@rs,rr,cc ext0f imm8
|
|
bitb rbd,imm4 cpirb rbd,@@rs,rr,cc ext8e imm8
|
|
bitb rbd,rs cpl rrd,@@rs ext8f imm8
|
|
bpt cpl rrd,addr exts rrd
|
|
call @@rd cpl rrd,addr(rs) extsb rd
|
|
call addr cpl rrd,imm32 extsl rqd
|
|
call addr(rd) cpl rrd,rrs halt
|
|
calr disp12 cpsd @@rd,@@rs,rr,cc in rd,@@rs
|
|
clr @@rd cpsdb @@rd,@@rs,rr,cc in rd,imm16
|
|
clr addr cpsdr @@rd,@@rs,rr,cc inb rbd,@@rs
|
|
clr addr(rd) cpsdrb @@rd,@@rs,rr,cc inb rbd,imm16
|
|
clr rd cpsi @@rd,@@rs,rr,cc inc @@rd,imm4m1
|
|
clrb @@rd cpsib @@rd,@@rs,rr,cc inc addr(rd),imm4m1
|
|
inc addr,imm4m1 ldb rbd,rs(rx) mult rrd,addr(rs)
|
|
inc rd,imm4m1 ldb rd(imm16),rbs mult rrd,imm16
|
|
incb @@rd,imm4m1 ldb rd(rx),rbs mult rrd,rs
|
|
incb addr(rd),imm4m1 ldctl ctrl,rs multl rqd,@@rs
|
|
incb addr,imm4m1 ldctl rd,ctrl multl rqd,addr
|
|
incb rbd,imm4m1 ldd @@rs,@@rd,rr multl rqd,addr(rs)
|
|
ind @@rd,@@rs,ra lddb @@rs,@@rd,rr multl rqd,imm32
|
|
indb @@rd,@@rs,rba lddr @@rs,@@rd,rr multl rqd,rrs
|
|
inib @@rd,@@rs,ra lddrb @@rs,@@rd,rr neg @@rd
|
|
inibr @@rd,@@rs,ra ldi @@rd,@@rs,rr neg addr
|
|
iret ldib @@rd,@@rs,rr neg addr(rd)
|
|
jp cc,@@rd ldir @@rd,@@rs,rr neg rd
|
|
jp cc,addr ldirb @@rd,@@rs,rr negb @@rd
|
|
jp cc,addr(rd) ldk rd,imm4 negb addr
|
|
jr cc,disp8 ldl @@rd,rrs negb addr(rd)
|
|
ld @@rd,imm16 ldl addr(rd),rrs negb rbd
|
|
ld @@rd,rs ldl addr,rrs nop
|
|
ld addr(rd),imm16 ldl rd(imm16),rrs or rd,@@rs
|
|
ld addr(rd),rs ldl rd(rx),rrs or rd,addr
|
|
ld addr,imm16 ldl rrd,@@rs or rd,addr(rs)
|
|
ld addr,rs ldl rrd,addr or rd,imm16
|
|
ld rd(imm16),rs ldl rrd,addr(rs) or rd,rs
|
|
ld rd(rx),rs ldl rrd,imm32 orb rbd,@@rs
|
|
ld rd,@@rs ldl rrd,rrs orb rbd,addr
|
|
ld rd,addr ldl rrd,rs(imm16) orb rbd,addr(rs)
|
|
ld rd,addr(rs) ldl rrd,rs(rx) orb rbd,imm8
|
|
ld rd,imm16 ldm @@rd,rs,n orb rbd,rbs
|
|
ld rd,rs ldm addr(rd),rs,n out @@rd,rs
|
|
ld rd,rs(imm16) ldm addr,rs,n out imm16,rs
|
|
ld rd,rs(rx) ldm rd,@@rs,n outb @@rd,rbs
|
|
lda rd,addr ldm rd,addr(rs),n outb imm16,rbs
|
|
lda rd,addr(rs) ldm rd,addr,n outd @@rd,@@rs,ra
|
|
lda rd,rs(imm16) ldps @@rs outdb @@rd,@@rs,rba
|
|
lda rd,rs(rx) ldps addr outib @@rd,@@rs,ra
|
|
ldar rd,disp16 ldps addr(rs) outibr @@rd,@@rs,ra
|
|
ldb @@rd,imm8 ldr disp16,rs pop @@rd,@@rs
|
|
ldb @@rd,rbs ldr rd,disp16 pop addr(rd),@@rs
|
|
ldb addr(rd),imm8 ldrb disp16,rbs pop addr,@@rs
|
|
ldb addr(rd),rbs ldrb rbd,disp16 pop rd,@@rs
|
|
ldb addr,imm8 ldrl disp16,rrs popl @@rd,@@rs
|
|
ldb addr,rbs ldrl rrd,disp16 popl addr(rd),@@rs
|
|
ldb rbd,@@rs mbit popl addr,@@rs
|
|
ldb rbd,addr mreq rd popl rrd,@@rs
|
|
ldb rbd,addr(rs) mres push @@rd,@@rs
|
|
ldb rbd,imm8 mset push @@rd,addr
|
|
ldb rbd,rbs mult rrd,@@rs push @@rd,addr(rs)
|
|
ldb rbd,rs(imm16) mult rrd,addr push @@rd,imm16
|
|
push @@rd,rs set addr,imm4 subl rrd,imm32
|
|
pushl @@rd,@@rs set rd,imm4 subl rrd,rrs
|
|
pushl @@rd,addr set rd,rs tcc cc,rd
|
|
pushl @@rd,addr(rs) setb @@rd,imm4 tccb cc,rbd
|
|
pushl @@rd,rrs setb addr(rd),imm4 test @@rd
|
|
res @@rd,imm4 setb addr,imm4 test addr
|
|
res addr(rd),imm4 setb rbd,imm4 test addr(rd)
|
|
res addr,imm4 setb rbd,rs test rd
|
|
res rd,imm4 setflg imm4 testb @@rd
|
|
res rd,rs sinb rbd,imm16 testb addr
|
|
resb @@rd,imm4 sinb rd,imm16 testb addr(rd)
|
|
resb addr(rd),imm4 sind @@rd,@@rs,ra testb rbd
|
|
resb addr,imm4 sindb @@rd,@@rs,rba testl @@rd
|
|
resb rbd,imm4 sinib @@rd,@@rs,ra testl addr
|
|
resb rbd,rs sinibr @@rd,@@rs,ra testl addr(rd)
|
|
resflg imm4 sla rd,imm8 testl rrd
|
|
ret cc slab rbd,imm8 trdb @@rd,@@rs,rba
|
|
rl rd,imm1or2 slal rrd,imm8 trdrb @@rd,@@rs,rba
|
|
rlb rbd,imm1or2 sll rd,imm8 trib @@rd,@@rs,rbr
|
|
rlc rd,imm1or2 sllb rbd,imm8 trirb @@rd,@@rs,rbr
|
|
rlcb rbd,imm1or2 slll rrd,imm8 trtdrb @@ra,@@rb,rbr
|
|
rldb rbb,rba sout imm16,rs trtib @@ra,@@rb,rr
|
|
rr rd,imm1or2 soutb imm16,rbs trtirb @@ra,@@rb,rbr
|
|
rrb rbd,imm1or2 soutd @@rd,@@rs,ra trtrb @@ra,@@rb,rbr
|
|
rrc rd,imm1or2 soutdb @@rd,@@rs,rba tset @@rd
|
|
rrcb rbd,imm1or2 soutib @@rd,@@rs,ra tset addr
|
|
rrdb rbb,rba soutibr @@rd,@@rs,ra tset addr(rd)
|
|
rsvd36 sra rd,imm8 tset rd
|
|
rsvd38 srab rbd,imm8 tsetb @@rd
|
|
rsvd78 sral rrd,imm8 tsetb addr
|
|
rsvd7e srl rd,imm8 tsetb addr(rd)
|
|
rsvd9d srlb rbd,imm8 tsetb rbd
|
|
rsvd9f srll rrd,imm8 xor rd,@@rs
|
|
rsvdb9 sub rd,@@rs xor rd,addr
|
|
rsvdbf sub rd,addr xor rd,addr(rs)
|
|
sbc rd,rs sub rd,addr(rs) xor rd,imm16
|
|
sbcb rbd,rbs sub rd,imm16 xor rd,rs
|
|
sc imm8 sub rd,rs xorb rbd,@@rs
|
|
sda rd,rs subb rbd,@@rs xorb rbd,addr
|
|
sdab rbd,rs subb rbd,addr xorb rbd,addr(rs)
|
|
sdal rrd,rs subb rbd,addr(rs) xorb rbd,imm8
|
|
sdl rd,rs subb rbd,imm8 xorb rbd,rbs
|
|
sdlb rbd,rs subb rbd,rbs xorb rbd,rbs
|
|
sdll rrd,rs subl rrd,@@rs
|
|
set @@rd,imm4 subl rrd,addr
|
|
set addr(rd),imm4 subl rrd,addr(rs)
|
|
@end smallexample
|
|
@iftex
|
|
@endgroup
|
|
@end iftex
|
|
@end ifset
|
|
|
|
@end ifset
|
|
|
|
@ifset MIPS
|
|
@ifset GENERIC
|
|
@page
|
|
@node MIPS-Dependent
|
|
@chapter MIPS Dependent Features
|
|
@end ifset
|
|
@ifclear GENERIC
|
|
@node Machine Dependencies
|
|
@chapter MIPS Dependent Features
|
|
@end ifclear
|
|
|
|
@cindex MIPS R2000
|
|
@cindex MIPS R3000
|
|
@cindex MIPS R4000
|
|
@cindex MIPS R6000
|
|
@sc{gnu} @code{@value{AS}} for @sc{mips} architectures supports the @sc{mips}
|
|
@sc{r2000}, @sc{r3000}, @sc{r4000} and @sc{r6000} processors. For information
|
|
about the @sc{mips} instruction set, see @cite{MIPS RISC Architecture}, by Kane
|
|
and Heindrich (Prentice-Hall). For an overview of @sc{mips} assembly
|
|
conventions, see ``Appendix D: Assembly Language Programming'' in the same
|
|
work.
|
|
|
|
@menu
|
|
* MIPS Opts:: Assembler options
|
|
* MIPS Object:: ECOFF object code
|
|
* MIPS Stabs:: Directives for debugging information
|
|
* MIPS ISA:: Directives to override the ISA level
|
|
@end menu
|
|
|
|
@node MIPS Opts
|
|
@section Assembler options
|
|
|
|
The @sc{mips} configurations of @sc{gnu} @code{@value{AS}} support these
|
|
special options:
|
|
|
|
@table @code
|
|
@cindex @code{-G} option (MIPS)
|
|
@item -G @var{num}
|
|
This option sets the largest size of an object that can be referenced
|
|
implicitly with the @code{gp} register. It is only accepted for targets
|
|
that use @sc{ecoff} format. The default value is 8.
|
|
|
|
@cindex @code{-EB} option (MIPS)
|
|
@cindex @code{-EL} option (MIPS)
|
|
@cindex MIPS big-endian output
|
|
@cindex MIPS little-endian output
|
|
@cindex big-endian output, MIPS
|
|
@cindex little-endian output, MIPS
|
|
@item -EB
|
|
@itemx -EL
|
|
Any @sc{mips} configuration of @code{@value{AS}} can select big-endian or
|
|
little-endian output at run time (unlike the other @sc{gnu} development
|
|
tools, which must be configured for one or the other). Use @samp{-EB}
|
|
to select big-endian output, and @samp{-EL} for little-endian.
|
|
|
|
@cindex MIPS architecture options
|
|
@item -mips1
|
|
@itemx -mips2
|
|
@itemx -mips3
|
|
Generate code for a particular MIPS Instruction Set Architecture level.
|
|
@samp{-mips1} corresponds to the @sc{r2000} and @sc{r3000} processors,
|
|
@samp{-mips2} to the @sc{r6000} processor, and @samp{-mips3} to the @sc{r4000}
|
|
processor. You can also switch instruction sets during the assembly; see
|
|
@ref{MIPS ISA,, Directives to override the ISA level}.
|
|
|
|
@item -m4650
|
|
@item -no-m4650
|
|
Generate code for the MIPS @sc{r4650} chip. This tells the assembler to accept
|
|
the @samp{mad} and @samp{madu} instruction, and to not schedule @samp{nop}
|
|
instructions around accesses to the @samp{HI} and @samp{LO} registers.
|
|
@samp{-no-m4650} turns off this option.
|
|
|
|
@item -mcpu=@var{CPU}
|
|
Generate code for a particular MIPS cpu. This has little effect on the
|
|
assembler, but it is passed by @code{@value{GCC}}.
|
|
|
|
@cindex @code{-nocpp} ignored (MIPS)
|
|
@item -nocpp
|
|
This option is ignored. It is accepted for command-line compatibility with
|
|
other assemblers, which use it to turn off C style preprocessing. With
|
|
@sc{gnu} @code{@value{AS}}, there is no need for @samp{-nocpp}, because the
|
|
@sc{gnu} assembler itself never runs the C preprocessor.
|
|
|
|
@item --trap
|
|
@itemx --no-break
|
|
@c FIXME! (1) reflect these options (next item too) in option summaries;
|
|
@c (2) stop teasing, say _which_ instructions expanded _how_.
|
|
@code{@value{AS}} automatically macro expands certain division and
|
|
multiplication instructions to check for overflow and division by zero. This
|
|
option causes @code{@value{AS}} to generate code to take a trap exception
|
|
rather than a break exception when an error is detected. The trap instructions
|
|
are only supported at Instruction Set Architecture level 2 and higher.
|
|
|
|
@item --break
|
|
@itemx --no-trap
|
|
Generate code to take a break exception rather than a trap exception when an
|
|
error is detected. This is the default.
|
|
@end table
|
|
|
|
@node MIPS Object
|
|
@section MIPS ECOFF object code
|
|
|
|
@cindex ECOFF sections
|
|
@cindex MIPS ECOFF sections
|
|
Assembling for a @sc{mips} @sc{ecoff} target supports some additional sections
|
|
besides the usual @code{.text}, @code{.data} and @code{.bss}. The
|
|
additional sections are @code{.rdata}, used for read-only data,
|
|
@code{.sdata}, used for small data, and @code{.sbss}, used for small
|
|
common objects.
|
|
|
|
@cindex small objects, MIPS ECOFF
|
|
@cindex @code{gp} register, MIPS
|
|
When assembling for @sc{ecoff}, the assembler uses the @code{$gp} (@code{$28})
|
|
register to form the address of a ``small object''. Any object in the
|
|
@code{.sdata} or @code{.sbss} sections is considered ``small'' in this sense.
|
|
For external objects, or for objects in the @code{.bss} section, you can use
|
|
the @code{@value{GCC}} @samp{-G} option to control the size of objects addressed via
|
|
@code{$gp}; the default value is 8, meaning that a reference to any object
|
|
eight bytes or smaller uses @code{$gp}. Passing @samp{-G 0} to
|
|
@code{@value{AS}} prevents it from using the @code{$gp} register on the basis
|
|
of object size (but the assembler uses @code{$gp} for objects in @code{.sdata}
|
|
or @code{sbss} in any case). The size of an object in the @code{.bss} section
|
|
is set by the @code{.comm} or @code{.lcomm} directive that defines it. The
|
|
size of an external object may be set with the @code{.extern} directive. For
|
|
example, @samp{.extern sym,4} declares that the object at @code{sym} is 4 bytes
|
|
in length, whie leaving @code{sym} otherwise undefined.
|
|
|
|
Using small @sc{ecoff} objects requires linker support, and assumes that the
|
|
@code{$gp} register is correctly initialized (normally done automatically by
|
|
the startup code). @sc{mips} @sc{ecoff} assembly code must not modify the
|
|
@code{$gp} register.
|
|
|
|
@node MIPS Stabs
|
|
@section Directives for debugging information
|
|
|
|
@cindex MIPS debugging directives
|
|
@sc{mips} @sc{ecoff} @code{@value{AS}} supports several directives used for
|
|
generating debugging information which are not support by traditional @sc{mips}
|
|
assemblers. These are @code{.def}, @code{.endef}, @code{.dim}, @code{.file},
|
|
@code{.scl}, @code{.size}, @code{.tag}, @code{.type}, @code{.val},
|
|
@code{.stabd}, @code{.stabn}, and @code{.stabs}. The debugging information
|
|
generated by the three @code{.stab} directives can only be read by @sc{gdb},
|
|
not by traditional @sc{mips} debuggers (this enhancement is required to fully
|
|
support C++ debugging). These directives are primarily used by compilers, not
|
|
assembly language programmers!
|
|
|
|
@node MIPS ISA
|
|
@section Directives to override the ISA level
|
|
|
|
@cindex MIPS ISA override
|
|
@kindex @code{.set mips@var{n}}
|
|
@sc{gnu} @code{@value{AS}} supports an additional directive to change the
|
|
@sc{mips} Instruction Set Architecture level on the fly: @code{.set
|
|
mips@var{n}}. @var{n} should be a number from 0 to 3. A value from 1 to 3
|
|
makes the assembler accept instructions for the corresponding @sc{isa} level,
|
|
from that point on in the assembly. @code{.set mips@var{n}} affects not only
|
|
which instructions are permitted, but also how certain macros are expanded.
|
|
@code{.set mips0} restores the @sc{isa} level to its original level: either the
|
|
level you selected with command line options, or the default for your
|
|
configuration. You can use this feature to permit specific @sc{r4000}
|
|
instructions while assembling in 32 bit mode. Use this directive with care!
|
|
|
|
Traditional @sc{mips} assemblers do not support this directive.
|
|
@end ifset
|
|
|
|
@ifset GENERIC
|
|
@c reverse effect of @down at top of generic Machine-Dep chapter
|
|
@raisesections
|
|
@end ifset
|
|
|
|
@node Acknowledgements
|
|
@chapter Acknowledgements
|
|
|
|
If you have contributed to @code{@value{AS}} and your name isn't listed here,
|
|
it is not meant as a slight. We just don't know about it. Send mail to the
|
|
maintainer, and we'll correct the situation. Currently (January 1994), the
|
|
maintainer is Ken Raeburn (email address @code{raeburn@@cygnus.com}).
|
|
|
|
Dean Elsner wrote the original @sc{gnu} assembler for the VAX.@footnote{Any more
|
|
details?}
|
|
|
|
Jay Fenlason maintained GAS for a while, adding support for GDB-specific debug
|
|
information and the 68k series machines, most of the preprocessing pass, and
|
|
extensive changes in @file{messages.c}, @file{input-file.c}, @file{write.c}.
|
|
|
|
K. Richard Pixley maintained GAS for a while, adding various enhancements and
|
|
many bug fixes, including merging support for several processors, breaking GAS
|
|
up to handle multiple object file format back ends (including heavy rewrite,
|
|
testing, an integration of the coff and b.out back ends), adding configuration
|
|
including heavy testing and verification of cross assemblers and file splits
|
|
and renaming, converted GAS to strictly ANSI C including full prototypes, added
|
|
support for m680[34]0 and cpu32, did considerable work on i960 including a COFF
|
|
port (including considerable amounts of reverse engineering), a SPARC opcode
|
|
file rewrite, DECstation, rs6000, and hp300hpux host ports, updated ``know''
|
|
assertions and made them work, much other reorganization, cleanup, and lint.
|
|
|
|
Ken Raeburn wrote the high-level BFD interface code to replace most of the code
|
|
in format-specific I/O modules.
|
|
|
|
The original VMS support was contributed by David L. Kashtan. Eric Youngdale
|
|
has done much work with it since.
|
|
|
|
The Intel 80386 machine description was written by Eliot Dresselhaus.
|
|
|
|
Minh Tran-Le at IntelliCorp contributed some AIX 386 support.
|
|
|
|
The Motorola 88k machine description was contributed by Devon Bowen of Buffalo
|
|
University and Torbjorn Granlund of the Swedish Institute of Computer Science.
|
|
|
|
Keith Knowles at the Open Software Foundation wrote the original MIPS back end
|
|
(@file{tc-mips.c}, @file{tc-mips.h}), and contributed Rose format support
|
|
(which hasn't been merged in yet). Ralph Campbell worked with the MIPS code to
|
|
support a.out format.
|
|
|
|
Support for the Zilog Z8k and Hitachi H8/300 and H8/500 processors (tc-z8k,
|
|
tc-h8300, tc-h8500), and IEEE 695 object file format (obj-ieee), was written by
|
|
Steve Chamberlain of Cygnus Support. Steve also modified the COFF back end to
|
|
use BFD for some low-level operations, for use with the H8/300 and AMD 29k
|
|
targets.
|
|
|
|
John Gilmore built the AMD 29000 support, added @code{.include} support, and
|
|
simplified the configuration of which versions accept which directives. He
|
|
updated the 68k machine description so that Motorola's opcodes always produced
|
|
fixed-size instructions (e.g. @code{jsr}), while synthetic instructions
|
|
remained shrinkable (@code{jbsr}). John fixed many bugs, including true tested
|
|
cross-compilation support, and one bug in relaxation that took a week and
|
|
required the proverbial one-bit fix.
|
|
|
|
Ian Lance Taylor of Cygnus Support merged the Motorola and MIT syntax for the
|
|
68k, completed support for some COFF targets (68k, i386 SVR3, and SCO Unix),
|
|
added support for MIPS ECOFF and ELF targets, and made a few other minor
|
|
patches.
|
|
|
|
Steve Chamberlain made @code{@value{AS}} able to generate listings.
|
|
|
|
Hewlett-Packard contributed support for the HP9000/300.
|
|
|
|
Jeff Law wrote GAS and BFD support for the native HPPA object format (SOM)
|
|
along with a fairly extensive HPPA testsuite (for both SOM and ELF object
|
|
formats). This work was supported by both the Center for Software Science at
|
|
the University of Utah and Cygnus Support.
|
|
|
|
Support for ELF format files has been worked on by Mark Eichin of Cygnus
|
|
Support (original, incomplete implementation for SPARC), Pete Hoogenboom and
|
|
Jeff Law at the University of Utah (HPPA mainly), Michael Meissner of the Open
|
|
Software Foundation (i386 mainly), and Ken Raeburn of Cygnus Support (sparc,
|
|
and some initial 64-bit support).
|
|
|
|
Several engineers at Cygnus Support have also provided many small bug fixes and
|
|
configuration enhancements.
|
|
|
|
Many others have contributed large or small bugfixes and enhancements. If
|
|
you have contributed significant work and are not mentioned on this list, and
|
|
want to be, let us know. Some of the history has been lost; we are not
|
|
intentionally leaving anyone out.
|
|
|
|
@node Index
|
|
@unnumbered Index
|
|
|
|
@printindex cp
|
|
|
|
@contents
|
|
@bye
|
|
@c Local Variables:
|
|
@c fill-column: 79
|
|
@c End:
|