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								libgloss/m68k/crt0.S
									
									
									
									
									
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								libgloss/m68k/crt0.S
									
									
									
									
									
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/*
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 * crt0.S -- startup file for m68k-coff
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 *
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 * Copyright (c) 1995, 1996, 1998 Cygnus Support
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 *
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 * The authors hereby grant permission to use, copy, modify, distribute,
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 * and license this software and its documentation for any purpose, provided
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 * that existing copyright notices are retained in all copies and that this
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 * notice is included verbatim in any distributions. No written agreement,
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 * license, or royalty fee is required for any of the authorized uses.
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 * Modifications to this software may be copyrighted by their authors
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 * and need not follow the licensing terms described here, provided that
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 * the new terms are clearly indicated on the first page of each file where
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 * they apply.
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 */
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#include "asm.h"
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	.title "crt0.S for m68k-coff"
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#define STACKSIZE	0x4000
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/*
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 * Define an empty environment.
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 */
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        .data
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        .align 2
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SYM (environ):
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        .long 0
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 	.align	2
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	.text
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/*
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 * These symbols are defined in C code, so they need to always be
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 * named with SYM because of the difference between object file formats.
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 */
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/* These are defined in C code. */
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	.extern SYM (main)
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	.extern SYM (exit)
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	.extern SYM (hardware_init_hook)
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	.extern SYM (software_init_hook)
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	.extern SYM (atexit)
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	.extern SYM(__do_global_dtors)
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/* 
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 * These values are set in the linker script, so they must be
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 * explicitly named here without SYM.
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 */
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	.extern __stack
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	.extern __bss_start
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	.extern _end
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/*
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 * set things up so the application will run. This *must* be called start.
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 */
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	.global SYM (start)
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SYM (start):
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	/*
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	 * put any hardware init code here
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	 */
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	/* See if user supplied their own stack (__stack != 0).  If not, then
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	 * default to using the value of %sp as set by the ROM monitor.
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	 */
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	movel	IMM(__stack), a0
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	cmpl	IMM(0), a0
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	jbeq    1f
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	movel	a0, sp
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1:
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	/* set up initial stack frame */
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	link	a6, IMM(-8)
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/*
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 * zero out the bss section.
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 */
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	movel	IMM(__bss_start), d1
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	movel	IMM(_end), d0
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	cmpl	d0, d1
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	jbeq	3f
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	movl	d1, a0
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	subl	d1, d0
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	subql	IMM(1), d0
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2:
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	clrb	(a0)+
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#ifndef __mcf5200__
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	dbra	d0, 2b
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	clrw	d0
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	subql	IMM(1), d0
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	jbcc	2b
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#else
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	subql	IMM(1), d0
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	jbpl	2b
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#endif
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3:
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/*
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 * initialize target specific stuff. Only execute these
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 * functions it they exist.
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 */
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	lea	SYM (hardware_init_hook), a0
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	cmpl	IMM(0),a0
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	jbeq	4f
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	jsr     (a0)
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4:
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	lea	SYM (software_init_hook), a0
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	cmpl	IMM(0),a0
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	jbeq	5f
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	jsr     (a0)
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5:
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/*
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 * call the main routine from the application to get it going.
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 * main (argc, argv, environ)
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 * we pass argv as a pointer to NULL.
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 */
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#ifdef ADD_DTORS
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	/* put __do_global_dtors in the atexit list so the destructors get run */
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	movel	IMM (SYM(__do_global_dtors)),(sp)
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	jsr	SYM (atexit)
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#endif
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	movel	IMM (__FINI_SECTION__),(sp)
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	jsr	SYM (atexit)
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	jsr	__INIT_SECTION__
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        pea     0
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        pea     SYM (environ)
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        pea     sp@(4)
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        pea     0
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	jsr	SYM (main)
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	movel	d0, sp@-
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/*
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 * drop down into exit incase the user doesn't. This should drop
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 * control back to the ROM monitor, if there is one. This calls the
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 * exit() from the C library so the C++ tables get cleaned up right.
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 */
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        jsr     SYM (exit)
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