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/*
* ====================================================
* Copyright (C) 1998, 2002, 2008 by Red Hat Inc. 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)
SOTYPE_FUNCTION(strchr)
SYM (strchr):
pushl ebp
movl esp,ebp
pushl edi
pushl ebx
xorl ebx,ebx
movl 8(ebp),edi
addb 12(ebp),bl
#ifndef __OPTIMIZE_SIZE__
/* Special case strchr(p,0). */
je L25
/* Do byte-wise checks until string is aligned. */
test $3,edi
je L5
movl edi,eax
movb (eax),cl
testb cl,cl
je L14
cmpb bl,cl
je L19
incl edi
test $3,edi
je L5
movl edi,eax
movb (eax),cl
testb cl,cl
je L14
cmpb bl,cl
je L19
incl edi
test $3,edi
je L5
movl edi,eax
movb (eax),cl
testb cl,cl
je L14
cmpb bl,cl
je L19
incl edi
/* create 4 byte mask which is just the desired byte repeated 4 times */
L5:
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
xorl ebx,ecx
leal -16843009(ecx),edx
notl ecx
andl ecx,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
#ifndef __OPTIMIZE_SIZE__
/* Special case strchr(p,0). */
#if 0
/* Hideous performance on modern machines. */
L25:
cld
movl $-1,ecx
xor eax,eax
repnz
scasb
leal -1(edi),eax
jmp L19
#endif
L25:
/* Do byte-wise checks until string is aligned. */
test $3,edi
je L26
movl edi,eax
movb (eax),cl
testb cl,cl
je L19
incl edi
test $3,edi
je L26
movl edi,eax
movb (eax),cl
testb cl,cl
je L19
incl edi
test $3,edi
je L26
movl edi,eax
movb (eax),cl
testb cl,cl
je L19
incl edi
L26:
subl $4,edi
/* loop performing 4 byte mask checking for desired 0 byte */
.p2align 4,,7
L27:
addl $4,edi
movl (edi),ecx
leal -16843009(ecx),edx
movl ecx,eax
notl eax
andl eax,edx
testl $-2139062144,edx
je L27
jmp L9
#endif /* !__OPTIMIZE_SIZE__ */
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