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/*
* crt0.S -- startup file for m68k-coff
*
* Copyright (c) 1995, 1996, 1998 Cygnus Support
*
* The authors hereby grant permission to use, copy, modify, distribute,
* and license this software and its documentation for any purpose, provided
* that existing copyright notices are retained in all copies and that this
* notice is included verbatim in any distributions. No written agreement,
* license, or royalty fee is required for any of the authorized uses.
* Modifications to this software may be copyrighted by their authors
* and need not follow the licensing terms described here, provided that
* the new terms are clearly indicated on the first page of each file where
* they apply.
*/
#include "asm.h"
.title "crt0.S for m68k-coff"
#define STACKSIZE 0x4000
/*
* Define an empty environment.
*/
.data
.align 2
SYM (environ):
.long 0
.align 2
.text
/*
* These symbols are defined in C code, so they need to always be
* named with SYM because of the difference between object file formats.
*/
/* These are defined in C code. */
.extern SYM (main)
.extern SYM (exit)
.extern SYM (hardware_init_hook)
.extern SYM (software_init_hook)
.extern SYM (atexit)
.extern SYM(__do_global_dtors)
/*
* These values are set in the linker script, so they must be
* explicitly named here without SYM.
*/
.extern __stack
.extern __bss_start
.extern _end
/*
* Set things up so the application will run. For historical reasons
* this is called 'start'. We set things up to provide '_start'
* as with other systems, but also provide a weak alias called
* 'start' for compatibility with existing linker scripts.
*/
.global SYM (start)
.weak SYM (start)
.set SYM (start),SYM(_start)
.global SYM (_start)
SYM (_start):
/*
* put any hardware init code here
*/
/* See if user supplied their own stack (__stack != 0). If not, then
* default to using the value of %sp as set by the ROM monitor.
*/
movel IMM(__stack), a0
cmpl IMM(0), a0
jbeq 1f
movel a0, sp
1:
/* set up initial stack frame */
link a6, IMM(-8)
/*
* zero out the bss section.
*/
movel IMM(__bss_start), d1
movel IMM(_end), d0
cmpl d0, d1
jbeq 3f
movl d1, a0
subl d1, d0
subql IMM(1), d0
2:
clrb (a0)+
#if !defined(__mcoldfire__)
dbra d0, 2b
clrw d0
subql IMM(1), d0
jbcc 2b
#else
subql IMM(1), d0
jbpl 2b
#endif
3:
/*
* initialize target specific stuff. Only execute these
* functions it they exist.
*/
PICLEA SYM (hardware_init_hook), a0
cmpl IMM(0),a0
jbeq 4f
jsr (a0)
4:
PICLEA SYM (software_init_hook), a0
cmpl IMM(0),a0
jbeq 5f
jsr (a0)
5:
/*
* call the main routine from the application to get it going.
* main (argc, argv, environ)
* we pass argv as a pointer to NULL.
*/
#ifdef ADD_DTORS
/* put __do_global_dtors in the atexit list so the destructors get run */
movel IMM (SYM(__do_global_dtors)),(sp)
PICCALL SYM (atexit)
#endif
movel IMM (__FINI_SECTION__),(sp)
PICCALL SYM (atexit)
PICCALL __INIT_SECTION__
pea 0
PICPEA SYM (environ),a0
pea sp@(4)
pea 0
PICCALL SYM (main)
movel d0, sp@-
/*
* drop down into exit incase the user doesn't. This should drop
* control back to the ROM monitor, if there is one. This calls the
* exit() from the C library so the C++ tables get cleaned up right.
*/
PICCALL SYM (exit)
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