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/* strlen(str) -- determine the length of the string STR.
Copyright (C) 2009-2013 Free Software Foundation, Inc.
Contributed by Ulrich Drepper <drepper@redhat.com>.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <sysdep.h>
.text
ENTRY(strlen)
xor %rax, %rax
mov %edi, %ecx
and $0x3f, %ecx
pxor %xmm0, %xmm0
cmp $0x30, %ecx
ja L(next)
movdqu (%rdi), %xmm1
pcmpeqb %xmm1, %xmm0
pmovmskb %xmm0, %edx
test %edx, %edx
jnz L(exit_less16)
mov %rdi, %rax
and $-16, %rax
jmp L(align16_start)
L(next):
mov %rdi, %rax
and $-16, %rax
pcmpeqb (%rax), %xmm0
mov $-1, %esi
sub %rax, %rcx
shl %cl, %esi
pmovmskb %xmm0, %edx
and %esi, %edx
jnz L(exit)
L(align16_start):
pxor %xmm0, %xmm0
pxor %xmm1, %xmm1
pxor %xmm2, %xmm2
pxor %xmm3, %xmm3
.p2align 4
L(align16_loop):
pcmpeqb 16(%rax), %xmm0
pmovmskb %xmm0, %edx
test %edx, %edx
jnz L(exit16)
pcmpeqb 32(%rax), %xmm1
pmovmskb %xmm1, %edx
test %edx, %edx
jnz L(exit32)
pcmpeqb 48(%rax), %xmm2
pmovmskb %xmm2, %edx
test %edx, %edx
jnz L(exit48)
pcmpeqb 64(%rax), %xmm3
pmovmskb %xmm3, %edx
lea 64(%rax), %rax
test %edx, %edx
jz L(align16_loop)
L(exit):
sub %rdi, %rax
L(exit_less16):
bsf %rdx, %rdx
add %rdx, %rax
ret
.p2align 4
L(exit16):
sub %rdi, %rax
bsf %rdx, %rdx
lea 16(%rdx,%rax), %rax
ret
.p2align 4
L(exit32):
sub %rdi, %rax
bsf %rdx, %rdx
lea 32(%rdx,%rax), %rax
ret
.p2align 4
L(exit48):
sub %rdi, %rax
bsf %rdx, %rdx
lea 48(%rdx,%rax), %rax
ret
END(strlen)
libc_hidden_builtin_def (strlen)
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