1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
|
/*
* 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 "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
|
