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/* strlen(str) -- determine the length of the string STR.
Copyright (C) 2009 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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <sysdep.h>
#include <init-arch.h>
/* Define multiple versions only for the definition in libc and for
the DSO. In static binaries we need strlen before the initialization
happened. */
#if defined SHARED && !defined NOT_IN_libc
.text
ENTRY(strlen)
.type strlen, @gnu_indirect_function
cmpl $0, __cpu_features+KIND_OFFSET(%rip)
jne 1f
call __init_cpu_features
1: leaq __strlen_sse2(%rip), %rax
testl $bit_SSE4_2, __cpu_features+CPUID_OFFSET+index_SSE4_2(%rip)
jz 2f
leaq __strlen_sse42(%rip), %rax
2: ret
END(strlen)
.section .text.sse4.2,"ax",@progbits
.align 16
.type __strlen_sse42, @function
__strlen_sse42:
cfi_startproc
CALL_MCOUNT
pxor %xmm1, %xmm1
movl %edi, %ecx
movq %rdi, %r8
andq $~15, %rdi
xor %edi, %ecx
pcmpeqb (%rdi), %xmm1
pmovmskb %xmm1, %edx
shrl %cl, %edx
shll %cl, %edx
andl %edx, %edx
jnz L(less16bytes)
pxor %xmm1, %xmm1
.p2align 4
L(more64bytes_loop):
pcmpistri $0x08, 16(%rdi), %xmm1
jz L(more32bytes)
pcmpistri $0x08, 32(%rdi), %xmm1
jz L(more48bytes)
pcmpistri $0x08, 48(%rdi), %xmm1
jz L(more64bytes)
add $64, %rdi
pcmpistri $0x08, (%rdi), %xmm1
jnz L(more64bytes_loop)
leaq (%rdi,%rcx), %rax
subq %r8, %rax
ret
.p2align 4
L(more32bytes):
leaq 16(%rdi,%rcx, 1), %rax
subq %r8, %rax
ret
.p2align 4
L(more48bytes):
leaq 32(%rdi,%rcx, 1), %rax
subq %r8, %rax
ret
.p2align 4
L(more64bytes):
leaq 48(%rdi,%rcx, 1), %rax
subq %r8, %rax
ret
.p2align 4
L(less16bytes):
subq %r8, %rdi
bsfl %edx, %eax
addq %rdi, %rax
ret
cfi_endproc
.size __strlen_sse42, .-__strlen_sse42
# undef ENTRY
# define ENTRY(name) \
.type __strlen_sse2, @function; \
.align 16; \
__strlen_sse2: cfi_startproc; \
CALL_MCOUNT
# undef END
# define END(name) \
cfi_endproc; .size __strlen_sse2, .-__strlen_sse2
# undef libc_hidden_builtin_def
/* It doesn't make sense to send libc-internal strlen calls through a PLT.
The speedup we get from using SSE4.2 instruction is likely eaten away
by the indirect call in the PLT. */
# define libc_hidden_builtin_def(name) \
.globl __GI_strlen; __GI_strlen = __strlen_sse2
#endif
#include "../strlen.S"
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