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/* strchr with SSE2 with bsf
Copyright (C) 2011-2019 Free Software Foundation, Inc.
Contributed by Intel Corporation.
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
<https://www.gnu.org/licenses/>. */
#if IS_IN (libc)
# include <sysdep.h>
# define CFI_PUSH(REG) \
cfi_adjust_cfa_offset (4); \
cfi_rel_offset (REG, 0)
# define CFI_POP(REG) \
cfi_adjust_cfa_offset (-4); \
cfi_restore (REG)
# define PUSH(REG) pushl REG; CFI_PUSH (REG)
# define POP(REG) popl REG; CFI_POP (REG)
# define PARMS 8
# define ENTRANCE PUSH(%edi)
# define RETURN POP(%edi); ret; CFI_PUSH(%edi);
# define STR1 PARMS
# define STR2 STR1+4
.text
ENTRY (__strchr_sse2_bsf)
ENTRANCE
mov STR1(%esp), %ecx
movd STR2(%esp), %xmm1
pxor %xmm2, %xmm2
mov %ecx, %edi
punpcklbw %xmm1, %xmm1
punpcklbw %xmm1, %xmm1
/* ECX has OFFSET. */
and $15, %ecx
pshufd $0, %xmm1, %xmm1
je L(loop)
/* Handle unaligned string. */
and $-16, %edi
movdqa (%edi), %xmm0
pcmpeqb %xmm0, %xmm2
pcmpeqb %xmm1, %xmm0
/* Find where NULL is. */
pmovmskb %xmm2, %edx
/* Check if there is a match. */
pmovmskb %xmm0, %eax
/* Remove the leading bytes. */
sarl %cl, %edx
sarl %cl, %eax
test %eax, %eax
je L(unaligned_no_match)
/* Check which byte is a match. */
bsf %eax, %eax
/* Is there a NULL? */
test %edx, %edx
je L(unaligned_match)
bsf %edx, %edx
cmpl %edx, %eax
/* Return NULL if NULL comes first. */
ja L(return_null)
L(unaligned_match):
add %edi, %eax
add %ecx, %eax
RETURN
.p2align 4
L(unaligned_no_match):
test %edx, %edx
jne L(return_null)
pxor %xmm2, %xmm2
add $16, %edi
.p2align 4
/* Loop start on aligned string. */
L(loop):
movdqa (%edi), %xmm0
pcmpeqb %xmm0, %xmm2
add $16, %edi
pcmpeqb %xmm1, %xmm0
pmovmskb %xmm2, %edx
pmovmskb %xmm0, %eax
or %eax, %edx
jnz L(matches)
movdqa (%edi), %xmm0
pcmpeqb %xmm0, %xmm2
add $16, %edi
pcmpeqb %xmm1, %xmm0
pmovmskb %xmm2, %edx
pmovmskb %xmm0, %eax
or %eax, %edx
jnz L(matches)
movdqa (%edi), %xmm0
pcmpeqb %xmm0, %xmm2
add $16, %edi
pcmpeqb %xmm1, %xmm0
pmovmskb %xmm2, %edx
pmovmskb %xmm0, %eax
or %eax, %edx
jnz L(matches)
movdqa (%edi), %xmm0
pcmpeqb %xmm0, %xmm2
add $16, %edi
pcmpeqb %xmm1, %xmm0
pmovmskb %xmm2, %edx
pmovmskb %xmm0, %eax
or %eax, %edx
jnz L(matches)
jmp L(loop)
L(matches):
pmovmskb %xmm2, %edx
test %eax, %eax
jz L(return_null)
bsf %eax, %eax
/* There is a match. First find where NULL is. */
test %edx, %edx
je L(match)
bsf %edx, %ecx
/* Check if NULL comes first. */
cmpl %ecx, %eax
ja L(return_null)
L(match):
sub $16, %edi
add %edi, %eax
RETURN
/* Return NULL. */
.p2align 4
L(return_null):
xor %eax, %eax
RETURN
END (__strchr_sse2_bsf)
#endif
|
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