153 lines
5.0 KiB
ArmAsm
153 lines
5.0 KiB
ArmAsm
/* Copyright (C) 2001-2016 Free Software Foundation, Inc.
|
|
Contributed by Hans-Peter Nilsson <hp@bitrange.com>
|
|
|
|
This file is free software; you can redistribute it and/or modify it
|
|
under the terms of the GNU General Public License as published by the
|
|
Free Software Foundation; either version 3, or (at your option) any
|
|
later version.
|
|
|
|
This file is distributed in the hope that it will be useful, but
|
|
WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
General Public License for more details.
|
|
|
|
Under Section 7 of GPL version 3, you are granted additional
|
|
permissions described in the GCC Runtime Library Exception, version
|
|
3.1, as published by the Free Software Foundation.
|
|
|
|
You should have received a copy of the GNU General Public License and
|
|
a copy of the GCC Runtime Library Exception along with this program;
|
|
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
% This is the crt0 equivalent for mmix-knuth-mmixware, for setting up
|
|
% things for compiler-generated assembly-code and for setting up things
|
|
% between where the simulator calls and main, and shutting things down on
|
|
% the way back. There's an actual crt0.o elsewhere, but that's a dummy.
|
|
|
|
% This file and the GCC output are supposed to be *reasonably*
|
|
% mmixal-compatible to enable people to re-use output with Knuth's mmixal.
|
|
% However, forward references are used more freely: we are using the
|
|
% binutils tools. Users of mmixal beware; you will sometimes have to
|
|
% re-order things or use temporary variables.
|
|
|
|
% Users of mmixal will want to set up 8H and 9H to be .text and .data
|
|
% respectively, so the compiler can switch between them pretending they're
|
|
% segments.
|
|
|
|
% This little treasure (some contents) is required so the 32 lowest
|
|
% address bits of user data will not be zero. Because of truncation,
|
|
% that would cause testcase gcc.c-torture/execute/980701-1.c to
|
|
% incorrectly fail.
|
|
|
|
.data ! mmixal:= 8H LOC Data_Segment
|
|
.p2align 3
|
|
dstart OCTA 2009
|
|
|
|
.text ! mmixal:= 9H LOC 8B; LOC #100
|
|
.global Main
|
|
|
|
% The __Stack_start symbol is provided by the link script.
|
|
stackpp OCTA __Stack_start
|
|
crtstxt OCTA _init % Assumed to be the lowest executed address.
|
|
OCTA __etext % Assumed to be beyond the highest executed address.
|
|
|
|
crtsdat OCTA dstart % Assumed to be the lowest accessed address.
|
|
OCTA _end % Assumed to be beyond the highest accessed address.
|
|
|
|
% "Main" is the magic symbol the simulator jumps to. We want to go
|
|
% on to "main".
|
|
% We need to set rG explicitly to avoid hard-to-debug situations.
|
|
Main SETL $255,32
|
|
PUT rG,$255
|
|
|
|
% Make sure we have valid memory for addresses in .text and .data (and
|
|
% .bss, but we include this in .data), for the benefit of mmo-using
|
|
% simulators that require validation of addresses for which contents
|
|
% is not present. Due to its implicit-zero nature, zeros in contents
|
|
% may be left out in the mmo format, but we don't know the boundaries
|
|
% of those zero-chunks; for mmo files from binutils, they correspond
|
|
% to the beginning and end of sections in objects before linking. We
|
|
% validate the contents by executing PRELD (0; one byte) on each
|
|
% 2048-byte-boundary of our .text .data, and we assume this size
|
|
% matches the magic lowest-denominator chunk-size for all
|
|
% validation-requiring simulators. The effect of the PRELD (any size)
|
|
% is assumed to be the same as initial loading of the contents, as
|
|
% long as the PRELD happens before the first PUSHJ/PUSHGO. If it
|
|
% happens after that, we'll need to distinguish between
|
|
% access-for-execution and read/write access.
|
|
|
|
GETA $255,crtstxt
|
|
LDOU $2,$255,0
|
|
ANDNL $2,#7ff % Align the start at a 2048-boundary.
|
|
LDOU $3,$255,8
|
|
SETL $4,2048
|
|
0H PRELD 0,$2,0
|
|
ADDU $2,$2,$4
|
|
CMP $255,$2,$3
|
|
BN $255,0B
|
|
|
|
GETA $255,crtsdat
|
|
LDOU $2,$255,0
|
|
ANDNL $2,#7ff
|
|
LDOU $3,$255,8
|
|
0H PRELD 0,$2,0
|
|
ADDU $2,$2,$4
|
|
CMP $255,$2,$3
|
|
BN $255,0B
|
|
|
|
% Initialize the stack pointer. It is supposedly made a global
|
|
% zero-initialized (allowed to change) register in crtn.S; we use the
|
|
% explicit number.
|
|
GETA $255,stackpp
|
|
LDOU $254,$255,0
|
|
|
|
PUSHJ $2,_init
|
|
|
|
#ifdef __MMIX_ABI_GNU__
|
|
% Copy argc and argv from their initial position to argument registers
|
|
% where necessary.
|
|
SET $231,$0
|
|
SET $232,$1
|
|
#else
|
|
% For the mmixware ABI, we need to move arguments. The return value will
|
|
% appear in $0.
|
|
SET $2,$1
|
|
SET $1,$0
|
|
#endif
|
|
|
|
PUSHJ $0,main
|
|
JMP exit
|
|
|
|
% Provide the first part of _init and _fini. Save the return address on the
|
|
% register stack. We eventually ignore the return address of these
|
|
% PUSHJ:s, so it doesn't matter that whether .init and .fini code calls
|
|
% functions or where they store rJ. We shouldn't get there, so die
|
|
% (TRAP Halt) if that happens.
|
|
|
|
.section .init,"ax",@progbits
|
|
.global _init
|
|
_init:
|
|
GET $0,:rJ
|
|
PUSHJ $1,0F
|
|
SETL $255,255
|
|
TRAP 0,0,0
|
|
0H IS @
|
|
|
|
% Register _fini to be executed as the last atexit function.
|
|
#ifdef __MMIX_ABI_GNU__
|
|
GETA $231,_fini
|
|
#else
|
|
GETA $1,_fini
|
|
#endif
|
|
PUSHJ $0,atexit
|
|
|
|
.section .fini,"ax",@progbits
|
|
.global _fini
|
|
_fini:
|
|
GET $0,:rJ
|
|
PUSHJ $1,0F
|
|
SETL $255,255
|
|
TRAP 0,0,0
|
|
0H IS @
|