| 1 |
30 |
unneback |
/*
|
| 2 |
|
|
* This is based on the mvme-crt0.S file from libgloss/rs6000.
|
| 3 |
|
|
* crt0.S -- startup file for PowerPC systems.
|
| 4 |
|
|
*
|
| 5 |
|
|
* Copyright (c) 1995 Cygnus Support
|
| 6 |
|
|
*
|
| 7 |
|
|
* The authors hereby grant permission to use, copy, modify, distribute,
|
| 8 |
|
|
* and license this software and its documentation for any purpose, provided
|
| 9 |
|
|
* that existing copyright notices are retained in all copies and that this
|
| 10 |
|
|
* notice is included verbatim in any distributions. No written agreement,
|
| 11 |
|
|
* license, or royalty fee is required for any of the authorized uses.
|
| 12 |
|
|
* Modifications to this software may be copyrighted by their authors
|
| 13 |
|
|
* and need not follow the licensing terms described here, provided that
|
| 14 |
|
|
* the new terms are clearly indicated on the first page of each file where
|
| 15 |
|
|
* they apply.
|
| 16 |
|
|
*
|
| 17 |
|
|
* $Id: start.S,v 1.2 2001-09-27 12:00:34 chris Exp $
|
| 18 |
|
|
*/
|
| 19 |
|
|
|
| 20 |
|
|
#include
|
| 21 |
|
|
#include "ppc-asm.h"
|
| 22 |
|
|
|
| 23 |
|
|
.file "start.s"
|
| 24 |
|
|
.section ".got2","aw"
|
| 25 |
|
|
.align 2
|
| 26 |
|
|
|
| 27 |
|
|
.LCTOC1 = .+32768
|
| 28 |
|
|
|
| 29 |
|
|
.extern FUNC_NAME(atexit)
|
| 30 |
|
|
.globl FUNC_NAME(__atexit)
|
| 31 |
|
|
.section ".sdata","aw"
|
| 32 |
|
|
.align 2
|
| 33 |
|
|
FUNC_NAME(__atexit): /* tell C's eabi-ctor's we have an atexit function */
|
| 34 |
|
|
.long FUNC_NAME(atexit)@fixup /* and that it is to register __do_global_dtors */
|
| 35 |
|
|
|
| 36 |
|
|
.section ".fixup","aw"
|
| 37 |
|
|
.align 2
|
| 38 |
|
|
.long FUNC_NAME(__atexit)
|
| 39 |
|
|
|
| 40 |
|
|
.section ".got2","aw"
|
| 41 |
|
|
.Ltable = .-.LCTOC1
|
| 42 |
|
|
.long .LCTOC1 /* address we think .LCTOC1 is loaded at */
|
| 43 |
|
|
|
| 44 |
|
|
.Lbss_start = .-.LCTOC1
|
| 45 |
|
|
.long __bss_start
|
| 46 |
|
|
|
| 47 |
|
|
.Lend = .-.LCTOC1
|
| 48 |
|
|
.long _end
|
| 49 |
|
|
|
| 50 |
|
|
.Lstack = .-.LCTOC1 /* stack address if set by user */
|
| 51 |
|
|
.long __stack
|
| 52 |
|
|
|
| 53 |
|
|
.text
|
| 54 |
|
|
.Lptr:
|
| 55 |
|
|
.long .LCTOC1-.Laddr
|
| 56 |
|
|
|
| 57 |
|
|
.globl _start
|
| 58 |
|
|
.type _start,@function
|
| 59 |
|
|
_start:
|
| 60 |
|
|
lis r5,0
|
| 61 |
|
|
mr r4,r5
|
| 62 |
|
|
ori r4,r4,0x0000 /* 0x2030 */
|
| 63 |
|
|
mtmsr r4
|
| 64 |
|
|
|
| 65 |
|
|
/* Add special purpose register initialization based upon the console driver
|
| 66 |
|
|
* initialization of these registers XXXXX
|
| 67 |
|
|
*/
|
| 68 |
|
|
|
| 69 |
|
|
bl .Laddr /* get current address */
|
| 70 |
|
|
|
| 71 |
|
|
.Laddr:
|
| 72 |
|
|
mflr r4 /* real address of .Laddr */
|
| 73 |
|
|
lwz r5,(.Lptr-.Laddr)(r4) /* linker generated address of .LCTOC1 */
|
| 74 |
|
|
add r5,r5,r4 /* correct to real pointer */
|
| 75 |
|
|
lwz r4,.Ltable(r5) /* get linker's idea of where .Laddr is */
|
| 76 |
|
|
subf r4,r4,r5 /* calculate difference between where linked and current */
|
| 77 |
|
|
|
| 78 |
|
|
/* clear bss */
|
| 79 |
|
|
lwz r6,.Lbss_start(r5) /* calculate beginning of the BSS */
|
| 80 |
|
|
lwz r7,.Lend(r5) /* calculate end of the BSS */
|
| 81 |
|
|
add r6,r6,r4 /* adjust pointers */
|
| 82 |
|
|
add r7,r7,r4
|
| 83 |
|
|
|
| 84 |
|
|
cmplw 1,r6,r7
|
| 85 |
|
|
bc 4,4,.Ldone
|
| 86 |
|
|
|
| 87 |
|
|
subf r8,r6,r7 /* number of bytes to zero */
|
| 88 |
|
|
srwi r9,r8,2 /* number of words to zero */
|
| 89 |
|
|
mtctr r9
|
| 90 |
|
|
li r0,0 /* zero to clear memory */
|
| 91 |
|
|
addi r6,r6,-4 /* adjust so we can use stwu */
|
| 92 |
|
|
.Lloop:
|
| 93 |
|
|
stwu r0,4(r6) /* zero bss */
|
| 94 |
|
|
bdnz .Lloop
|
| 95 |
|
|
|
| 96 |
|
|
.Ldone:
|
| 97 |
|
|
|
| 98 |
|
|
lwz r0,.Lstack(r5) /* stack address or 0 */
|
| 99 |
|
|
cmplwi 1,r0,0 /* equal to 0? */
|
| 100 |
|
|
bc 12,6,.Lnostack /* use default stack if == 0 */
|
| 101 |
|
|
mr sp,r0 /* use user defined stack */
|
| 102 |
|
|
|
| 103 |
|
|
.Lnostack:
|
| 104 |
|
|
/* set up initial stack frame */
|
| 105 |
|
|
addi sp,sp,-4 /* make sure we don't overwrite debug mem */
|
| 106 |
|
|
lis r0,0
|
| 107 |
|
|
stw r0,0(sp) /* clear back chain */
|
| 108 |
|
|
stwu sp,-56(sp) /* push another stack frame */
|
| 109 |
|
|
|
| 110 |
|
|
/* Let her rip */
|
| 111 |
|
|
bl FUNC_NAME(boot_card)
|
| 112 |
|
|
|
| 113 |
|
|
/* return value from boot_card is argument to exit */
|
| 114 |
|
|
/* bl FUNC_NAME(exit) */
|
| 115 |
|
|
trap
|
| 116 |
|
|
.Lstart:
|
| 117 |
|
|
.size _start,.Lstart-_start
|
