49 lines
1.1 KiB
ArmAsm
49 lines
1.1 KiB
ArmAsm
|
/*
|
||
|
|
* Copyright (C) Paul Mackerras 1997.
|
||
|
|
*
|
||
|
|
* This program 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
|
||
|
|
* 2 of the License, or (at your option) any later version.
|
||
|
|
*
|
||
|
|
* NOTE: this code runs in 32 bit mode and is packaged as ELF32.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <asm/ppc_asm.h>
|
||
|
|
|
||
|
|
.text
|
||
|
|
.globl _start
|
||
|
|
_start:
|
||
|
|
lis r9,_start@h
|
||
|
|
lis r8,_etext@ha
|
||
|
|
addi r8,r8,_etext@l
|
||
|
|
1: dcbf r0,r9
|
||
|
|
icbi r0,r9
|
||
|
|
addi r9,r9,0x20
|
||
|
|
cmplwi 0,r9,8
|
||
|
|
blt 1b
|
||
|
|
sync
|
||
|
|
isync
|
||
|
|
|
||
|
|
## Clear out the BSS as per ANSI C requirements
|
||
|
|
|
||
|
|
lis r7,_end@ha
|
||
|
|
addi r7,r7,_end@l # r7 = &_end
|
||
|
|
lis r8,__bss_start@ha #
|
||
|
|
addi r8,r8,__bss_start@l # r8 = &_bss_start
|
||
|
|
|
||
|
|
## Determine how large an area, in number of words, to clear
|
||
|
|
|
||
|
|
subf r7,r8,r7 # r7 = &_end - &_bss_start + 1
|
||
|
|
addi r7,r7,3 # r7 += 3
|
||
|
|
srwi. r7,r7,2 # r7 = size in words.
|
||
|
|
beq 3f # If the size is zero, don't bother
|
||
|
|
addi r8,r8,-4 # r8 -= 4
|
||
|
|
mtctr r7 # SPRN_CTR = number of words to clear
|
||
|
|
li r0,0 # r0 = 0
|
||
|
|
2: stwu r0,4(r8) # Clear out a word
|
||
|
|
bdnz 2b # Keep clearing until done
|
||
|
|
3:
|
||
|
|
b start
|
||
|
|
|