2017-04-11 21:13:36 +00:00
|
|
|
/*
|
|
|
|
|
* ====================================================
|
|
|
|
|
* 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 (strlen)
|
|
|
|
|
SOTYPE_FUNCTION(strlen)
|
|
|
|
|
|
|
|
|
|
SYM (strlen):
|
|
|
|
|
|
|
|
|
|
pushl ebp
|
|
|
|
|
movl esp,ebp
|
|
|
|
|
pushl edi
|
2017-10-07 00:16:47 +00:00
|
|
|
#ifdef __iamcu__
|
|
|
|
|
movl eax,edx
|
|
|
|
|
#else
|
2017-04-11 21:13:36 +00:00
|
|
|
movl 8(ebp),edx
|
2017-10-07 00:16:47 +00:00
|
|
|
#endif
|
2017-04-11 21:13:36 +00:00
|
|
|
|
2017-10-07 00:16:47 +00:00
|
|
|
#if defined __OPTIMIZE_SIZE__ || defined __iamcu__
|
2017-04-11 21:13:36 +00:00
|
|
|
cld
|
|
|
|
|
movl edx,edi
|
|
|
|
|
movl $4294967295,ecx
|
|
|
|
|
xor eax,eax
|
|
|
|
|
repnz
|
|
|
|
|
scasb
|
|
|
|
|
#else
|
|
|
|
|
/* Modern x86 hardware is much faster at double-word
|
|
|
|
|
manipulation than with bytewise repnz scasb. */
|
|
|
|
|
|
|
|
|
|
/* Do byte-wise checks until string is aligned. */
|
|
|
|
|
movl edx,edi
|
|
|
|
|
test $3,edi
|
|
|
|
|
je L5
|
|
|
|
|
movb (edi),cl
|
|
|
|
|
incl edi
|
|
|
|
|
testb cl,cl
|
|
|
|
|
je L15
|
|
|
|
|
|
|
|
|
|
test $3,edi
|
|
|
|
|
je L5
|
|
|
|
|
movb (edi),cl
|
|
|
|
|
incl edi
|
|
|
|
|
testb cl,cl
|
|
|
|
|
je L15
|
|
|
|
|
|
|
|
|
|
test $3,edi
|
|
|
|
|
je L5
|
|
|
|
|
movb (edi),cl
|
|
|
|
|
incl edi
|
|
|
|
|
testb cl,cl
|
|
|
|
|
je L15
|
|
|
|
|
|
|
|
|
|
L5:
|
|
|
|
|
subl $4,edi
|
|
|
|
|
|
|
|
|
|
/* loop performing 4 byte mask checking for desired 0 byte */
|
|
|
|
|
.p2align 4,,7
|
|
|
|
|
L10:
|
|
|
|
|
addl $4,edi
|
|
|
|
|
movl (edi),ecx
|
|
|
|
|
leal -16843009(ecx),eax
|
|
|
|
|
notl ecx
|
|
|
|
|
andl ecx,eax
|
|
|
|
|
testl $-2139062144,eax
|
|
|
|
|
je L10
|
|
|
|
|
|
|
|
|
|
/* Find which of four bytes is 0. */
|
|
|
|
|
notl ecx
|
|
|
|
|
incl edi
|
|
|
|
|
|
|
|
|
|
testb cl,cl
|
|
|
|
|
je L15
|
|
|
|
|
incl edi
|
|
|
|
|
shrl $8,ecx
|
|
|
|
|
|
|
|
|
|
testb cl,cl
|
|
|
|
|
je L15
|
|
|
|
|
incl edi
|
|
|
|
|
shrl $8,ecx
|
|
|
|
|
|
|
|
|
|
testb cl,cl
|
|
|
|
|
je L15
|
|
|
|
|
incl edi
|
|
|
|
|
|
|
|
|
|
#endif
|
|
|
|
|
|
|
|
|
|
L15:
|
|
|
|
|
subl edx,edi
|
|
|
|
|
leal -1(edi),eax
|
|
|
|
|
|
|
|
|
|
leal -4(ebp),esp
|
|
|
|
|
popl edi
|
|
|
|
|
leave
|
|
|
|
|
ret
|
