150 lines
3.3 KiB
ArmAsm
150 lines
3.3 KiB
ArmAsm
/*
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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. For historical reasons
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* this is called 'start'. We set things up to provide '_start'
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* as with other systems, but also provide a weak alias called
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* 'start' for compatibility with existing linker scripts.
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*/
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.global SYM (start)
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.weak SYM (start)
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.set SYM (start),SYM(_start)
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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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#if !defined(__mcoldfire__)
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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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PICLEA 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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PICLEA 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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PICCALL SYM (atexit)
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#endif
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movel IMM (__FINI_SECTION__),(sp)
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PICCALL SYM (atexit)
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PICCALL __INIT_SECTION__
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pea 0
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PICPEA SYM (environ),a0
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pea sp@(4)
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pea 0
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PICCALL 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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PICCALL SYM (exit)
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