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
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
|
/*
* ====================================================
* Copyright (C) 1998 by Cygnus Solutions. All rights reserved.
*
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
#include "i386mach.h"
.global SYM (strchr)
SYM (strchr):
pushl ebp
movl esp,ebp
pushl edi
pushl ebx
xorl ebx,ebx
movl 8(ebp),edi
movb 12(ebp),bl
#ifndef __OPTIMIZE_SIZE__
/* check if string is aligned, if not do check one byte at a time */
test $3,edi
jne L9
/* create 4 byte mask which is just the desired byte repeated 4 times */
movl ebx,ecx
sall $8,ebx
subl $4,edi
orl ecx,ebx
movl ebx,edx
sall $16,ebx
orl edx,ebx
/* loop performing 4 byte mask checking for 0 byte or desired byte */
.p2align 4,,7
L10:
addl $4,edi
movl (edi),ecx
leal -16843009(ecx),edx
movl ecx,eax
notl eax
andl eax,edx
testl $-2139062144,edx
jne L9
movl ebx,eax
xorl ecx,eax
leal -16843009(eax),edx
notl eax
andl eax,edx
testl $-2139062144,edx
je L10
#endif /* not __OPTIMIZE_SIZE__ */
/* loop while (*s && *s++ != c) */
L9:
leal -1(edi),eax
.p2align 4,,7
L15:
incl eax
movb (eax),dl
testb dl,dl
je L14
cmpb bl,dl
jne L15
L14:
/* if (*s == c) return address otherwise return NULL */
cmpb bl,(eax)
je L19
xorl eax,eax
L19:
leal -8(ebp),esp
popl ebx
popl edi
leave
ret
|
