320 lines
12 KiB
C
320 lines
12 KiB
C
/* b.out object file format
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Copyright 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 2000,
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2002 Free Software Foundation, Inc.
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This file is part of GAS, the GNU Assembler.
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GAS is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2,
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or (at your option) any later version.
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GAS is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
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the GNU General Public License for more details.
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You should have received a copy of the GNU General Public
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License along with GAS; see the file COPYING. If not, write
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to the Free Software Foundation, 59 Temple Place - Suite 330, Cambridge, MA
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02139, USA. */
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/*
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* This file is a modified version of 'a.out.h'. It is to be used in all GNU
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* tools modified to support the i80960 b.out format (or tools that operate on
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* object files created by such tools).
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*
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* All i80960 development is done in a CROSS-DEVELOPMENT environment. I.e.,
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* object code is generated on, and executed under the direction of a symbolic
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* debugger running on, a host system. We do not want to be subject to the
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* vagaries of which host it is or whether it supports COFF or a.out format, or
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* anything else. We DO want to:
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*
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* o always generate the same format object files, regardless of host.
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*
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* o have an 'a.out' header that we can modify for our own purposes
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* (the 80960 is typically an embedded processor and may require
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* enhanced linker support that the normal a.out.h header can't
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* accommodate).
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*
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* As for byte-ordering, the following rules apply:
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*
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* o Text and data that is actually downloaded to the target is always
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* in i80960 (little-endian) order.
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*
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* o All other numbers (in the header, symbols, relocation directives)
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* are in host byte-order: object files CANNOT be lifted from a
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* little-end host and used on a big-endian (or vice versa) without
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* modification.
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* ==> THIS IS NO LONGER TRUE USING BFD. WE CAN GENERATE ANY BYTE ORDER
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* FOR THE HEADER, AND READ ANY BYTE ORDER. PREFERENCE WOULD BE TO
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* USE LITTLE-ENDIAN BYTE ORDER THROUGHOUT, REGARDLESS OF HOST. <==
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*
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* o The downloader ('comm960') takes care to generate a pseudo-header
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* with correct (i80960) byte-ordering before shipping text and data
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* off to the NINDY monitor in the target systems. Symbols and
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* relocation info are never sent to the target.
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*/
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#define OBJ_BOUT 1
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#define OUTPUT_FLAVOR bfd_target_aout_flavour
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#include "targ-cpu.h"
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#define OBJ_DEFAULT_OUTPUT_FILE_NAME "b.out"
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extern const short seg_N_TYPE[];
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extern const segT N_TYPE_seg[];
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#define BMAGIC 0415
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/* We don't accept the following (see N_BADMAG macro).
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* They're just here so GNU code will compile.
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*/
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#define OMAGIC 0407 /* old impure format */
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#define NMAGIC 0410 /* read-only text */
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#define ZMAGIC 0413 /* demand load format */
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#ifndef DEFAULT_MAGIC_NUMBER_FOR_OBJECT_FILE
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#define DEFAULT_MAGIC_NUMBER_FOR_OBJECT_FILE (BMAGIC)
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#endif /* DEFAULT_MAGIC_NUMBER_FOR_OBJECT_FILE */
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/* FILE HEADER
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* All 'lengths' are given as a number of bytes.
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* All 'alignments' are for relinkable files only; an alignment of
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* 'n' indicates the corresponding segment must begin at an
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* address that is a multiple of (2**n).
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*/
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struct exec
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{
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/* Standard stuff */
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unsigned long a_magic; /* Identifies this as a b.out file */
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unsigned long a_text; /* Length of text */
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unsigned long a_data; /* Length of data */
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unsigned long a_bss; /* Length of runtime uninitialized data area */
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unsigned long a_syms; /* Length of symbol table */
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unsigned long a_entry; /* Runtime start address */
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unsigned long a_trsize; /* Length of text relocation info */
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unsigned long a_drsize; /* Length of data relocation info */
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/* Added for i960 */
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unsigned long a_tload; /* Text runtime load address */
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unsigned long a_dload; /* Data runtime load address */
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unsigned char a_talign; /* Alignment of text segment */
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unsigned char a_dalign; /* Alignment of data segment */
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unsigned char a_balign; /* Alignment of bss segment */
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unsigned char a_relaxable; /* Contains enough info to relax */
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};
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#define N_BADMAG(x) (((x).a_magic)!=BMAGIC)
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#define N_TXTOFF(x) ( sizeof (struct exec) )
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#define N_DATOFF(x) ( N_TXTOFF(x) + (x).a_text )
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#define N_TROFF(x) ( N_DATOFF(x) + (x).a_data )
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#define N_DROFF(x) ( N_TROFF(x) + (x).a_trsize )
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#define N_SYMOFF(x) ( N_DROFF(x) + (x).a_drsize )
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#define N_STROFF(x) ( N_SYMOFF(x) + (x).a_syms )
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/* A single entry in the symbol table
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*/
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struct nlist
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{
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union
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{
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char *n_name;
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struct nlist *n_next;
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long n_strx; /* Index into string table */
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}
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n_un;
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unsigned char n_type; /* See below */
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char n_other; /* Used in i80960 support -- see below */
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short n_desc;
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unsigned long n_value;
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};
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typedef struct nlist obj_symbol_type;
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/* Legal values of n_type
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*/
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#define N_UNDF 0 /* Undefined symbol */
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#define N_ABS 2 /* Absolute symbol */
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#define N_TEXT 4 /* Text symbol */
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#define N_DATA 6 /* Data symbol */
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#define N_BSS 8 /* BSS symbol */
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#define N_FN 31 /* Filename symbol */
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#define N_EXT 1 /* External symbol (OR'd in with one of above) */
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#define N_TYPE 036 /* Mask for all the type bits */
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#define N_STAB 0340 /* Mask for all bits used for SDB entries */
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#ifndef CUSTOM_RELOC_FORMAT
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struct relocation_info
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{
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int r_address; /* File address of item to be relocated */
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unsigned
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r_index:24, /* Index of symbol on which relocation is based*/
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r_pcrel:1, /* 1 => relocate PC-relative; else absolute
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* On i960, pc-relative implies 24-bit
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* address, absolute implies 32-bit.
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*/
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r_length:2, /* Number of bytes to relocate:
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* 0 => 1 byte
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* 1 => 2 bytes
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* 2 => 4 bytes -- only value used for i960
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*/
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r_extern:1, r_bsr:1, /* Something for the GNU NS32K assembler */
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r_disp:1, /* Something for the GNU NS32K assembler */
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r_callj:1, /* 1 if relocation target is an i960 'callj' */
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nuthin:1; /* Unused */
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};
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#endif /* CUSTOM_RELOC_FORMAT */
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/*
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* Macros to extract information from a symbol table entry.
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* This syntaxic indirection allows independence regarding a.out or coff.
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* The argument (s) of all these macros is a pointer to a symbol table entry.
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*/
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/* Predicates */
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/* True if the symbol is external */
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#define S_IS_EXTERNAL(s) ((s)->sy_symbol.n_type & N_EXT)
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/* True if symbol has been defined, ie is in N_{TEXT,DATA,BSS,ABS} or N_EXT */
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#define S_IS_DEFINED(s) ((S_GET_TYPE(s) != N_UNDF) || (S_GET_DESC(s) != 0))
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/* Return true for symbols that should not be reduced to section
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symbols or eliminated from expressions, because they may be
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overridden by the linker. */
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#define S_FORCE_RELOC(s) \
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(!SEG_NORMAL (S_GET_SEGMENT (s)))
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#define S_IS_COMMON(s) \
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(S_GET_TYPE (s) == N_UNDF && S_GET_VALUE (s) != 0)
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#define S_IS_REGISTER(s) ((s)->sy_symbol.n_type == N_REGISTER)
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/* True if a debug special symbol entry */
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#define S_IS_DEBUG(s) ((s)->sy_symbol.n_type & N_STAB)
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/* True if a symbol is local symbol name */
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#define S_IS_LOCAL(s) \
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((S_GET_NAME (s) \
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&& !S_IS_DEBUG (s) \
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&& (strchr (S_GET_NAME (s), '\001') != NULL \
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|| strchr (S_GET_NAME (s), '\002') != NULL \
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|| (S_LOCAL_NAME(s) && !flag_keep_locals))) \
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|| (flag_strip_local_absolute \
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&& !S_IS_EXTERNAL(s) \
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&& S_GET_SEGMENT(s) == absolute_section))
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/* True if a symbol is not defined in this file */
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#define S_IS_EXTERN(s) ((s)->sy_symbol.n_type & N_EXT)
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/* True if the symbol has been generated because of a .stabd directive */
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#define S_IS_STABD(s) (S_GET_NAME(s) == NULL)
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/* Accessors */
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/* The name of the symbol */
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#define S_GET_NAME(s) ((s)->sy_symbol.n_un.n_name)
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/* The pointer to the string table */
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#define S_GET_OFFSET(s) ((s)->sy_symbol.n_un.n_strx)
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/* The type of the symbol */
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#define S_GET_TYPE(s) ((s)->sy_symbol.n_type & N_TYPE)
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/* The numeric value of the segment */
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#define S_GET_SEGMENT(s) (N_TYPE_seg[S_GET_TYPE(s)])
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/* The n_other expression value */
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#define S_GET_OTHER(s) ((s)->sy_symbol.n_other)
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/* The n_desc expression value */
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#define S_GET_DESC(s) ((s)->sy_symbol.n_desc)
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/* Modifiers */
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/* Assume that a symbol cannot be simultaneously in more than on segment */
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/* set segment */
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#define S_SET_SEGMENT(s,seg) ((s)->sy_symbol.n_type &= ~N_TYPE,(s)->sy_symbol.n_type|=SEGMENT_TO_SYMBOL_TYPE(seg))
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/* The symbol is external */
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#define S_SET_EXTERNAL(s) ((s)->sy_symbol.n_type |= N_EXT)
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/* The symbol is not external */
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#define S_CLEAR_EXTERNAL(s) ((s)->sy_symbol.n_type &= ~N_EXT)
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/* Set the name of the symbol */
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#define S_SET_NAME(s,v) ((s)->sy_symbol.n_un.n_name = (v))
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/* Set the offset in the string table */
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#define S_SET_OFFSET(s,v) ((s)->sy_symbol.n_un.n_strx = (v))
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/* Set the n_other expression value */
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#define S_SET_OTHER(s,v) ((s)->sy_symbol.n_other = (v))
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/* Set the n_desc expression value */
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#define S_SET_DESC(s,v) ((s)->sy_symbol.n_desc = (v))
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/* Set the n_type value */
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#define S_SET_TYPE(s,v) ((s)->sy_symbol.n_type = (v))
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/* File header macro and type definition */
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#define H_GET_FILE_SIZE(h) (sizeof (struct exec) + \
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H_GET_TEXT_SIZE(h) + H_GET_DATA_SIZE(h) + \
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H_GET_SYMBOL_TABLE_SIZE(h) + \
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H_GET_TEXT_RELOCATION_SIZE(h) + \
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H_GET_DATA_RELOCATION_SIZE(h) + \
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(h)->string_table_size)
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#define H_GET_HEADER_SIZE(h) (sizeof (struct exec))
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#define H_GET_TEXT_SIZE(h) ((h)->header.a_text)
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#define H_GET_DATA_SIZE(h) ((h)->header.a_data)
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#define H_GET_BSS_SIZE(h) ((h)->header.a_bss)
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#define H_GET_TEXT_RELOCATION_SIZE(h) ((h)->header.a_trsize)
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#define H_GET_DATA_RELOCATION_SIZE(h) ((h)->header.a_drsize)
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#define H_GET_SYMBOL_TABLE_SIZE(h) ((h)->header.a_syms)
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#define H_GET_MAGIC_NUMBER(h) ((h)->header.a_info)
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#define H_GET_ENTRY_POINT(h) ((h)->header.a_entry)
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#define H_GET_STRING_SIZE(h) ((h)->string_table_size)
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#define H_GET_LINENO_SIZE(h) (0)
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#ifdef EXEC_MACHINE_TYPE
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#define H_GET_MACHINE_TYPE(h) ((h)->header.a_machtype)
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#endif /* EXEC_MACHINE_TYPE */
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#ifdef EXEC_VERSION
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#define H_GET_VERSION(h) ((h)->header.a_version)
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#endif /* EXEC_VERSION */
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#define H_SET_TEXT_SIZE(h,v) ((h)->header.a_text = (v))
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#define H_SET_DATA_SIZE(h,v) ((h)->header.a_data = (v))
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#define H_SET_BSS_SIZE(h,v) ((h)->header.a_bss = (v))
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#define H_SET_RELOCATION_SIZE(h,t,d) (H_SET_TEXT_RELOCATION_SIZE((h),(t)),\
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H_SET_DATA_RELOCATION_SIZE((h),(d)))
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#define H_SET_TEXT_RELOCATION_SIZE(h,v) ((h)->header.a_trsize = (v))
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#define H_SET_DATA_RELOCATION_SIZE(h,v) ((h)->header.a_drsize = (v))
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#define H_SET_SYMBOL_TABLE_SIZE(h,v) ((h)->header.a_syms = (v) * \
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sizeof (struct nlist))
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#define H_SET_MAGIC_NUMBER(h,v) ((h)->header.a_magic = (v))
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#define H_SET_ENTRY_POINT(h,v) ((h)->header.a_entry = (v))
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#define H_SET_STRING_SIZE(h,v) ((h)->string_table_size = (v))
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#ifdef EXEC_MACHINE_TYPE
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#define H_SET_MACHINE_TYPE(h,v) ((h)->header.a_machtype = (v))
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#endif /* EXEC_MACHINE_TYPE */
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#ifdef EXEC_VERSION
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#define H_SET_VERSION(h,v) ((h)->header.a_version = (v))
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#endif /* EXEC_VERSION */
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typedef struct
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{
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struct exec header; /* a.out header */
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long string_table_size; /* names + '\0' + sizeof (int) */
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}
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object_headers;
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/* unused hooks. */
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#define OBJ_EMIT_LINENO(a, b, c) {;}
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#define obj_pre_write_hook(a) {;}
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#if __STDC__
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struct fix;
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#endif
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extern void tc_aout_fix_to_chars PARAMS ((char *where,
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struct fix *fixP,
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relax_addressT segment_address));
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extern void tc_bout_fix_to_chars PARAMS ((char *where,
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struct fix *fixP,
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relax_addressT segment_address));
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#define AOUT_STABS
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