glibc/sysdeps/x86_64/strrchr.S

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2009-04-14 05:58:16 +00:00
/* strrchr (str, ch) -- Return pointer to last occurrence of CH in STR.
For AMD x86-64.
Copyright (C) 2009-2013 Free Software Foundation, Inc.
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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/>. */
2009-04-14 05:58:16 +00:00
#include <sysdep.h>
.text
ENTRY (strrchr)
movd %esi, %xmm1
movq %rdi, %rcx
punpcklbw %xmm1, %xmm1
andq $~15, %rdi
pxor %xmm2, %xmm2
punpcklbw %xmm1, %xmm1
orl $0xffffffff, %esi
movdqa (%rdi), %xmm0
pshufd $0, %xmm1, %xmm1
subq %rdi, %rcx
movdqa %xmm0, %xmm3
leaq 16(%rdi), %rdi
pcmpeqb %xmm1, %xmm0
pcmpeqb %xmm2, %xmm3
shl %cl, %esi
pmovmskb %xmm0, %edx
pmovmskb %xmm3, %ecx
andl %esi, %edx
andl %esi, %ecx
xorl %eax, %eax
movl %edx, %esi
orl %ecx, %esi
jnz 1f
2: movdqa (%rdi), %xmm0
leaq 16(%rdi), %rdi
movdqa %xmm0, %xmm3
pcmpeqb %xmm1, %xmm0
pcmpeqb %xmm2, %xmm3
pmovmskb %xmm0, %edx
pmovmskb %xmm3, %ecx
movl %edx, %esi
orl %ecx, %esi
jz 2b
1: bsfl %ecx, %r9d
movl $0xffffffff, %r8d
movl $31, %ecx
jnz 5f
bsrl %edx, %edx
jz 2b
leaq -16(%rdi,%rdx), %rax
jmp 2b
5: subl %r9d, %ecx
shrl %cl, %r8d
andl %r8d, %edx
bsrl %edx, %edx
jz 4f
leaq -16(%rdi,%rdx), %rax
4: ret
END (strrchr)
weak_alias (strrchr, rindex)
libc_hidden_builtin_def (strrchr)