mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-18 08:51:06 +00:00
51ddd2c01e
This patch defines bit_XXX and index_XXX and use them to check processor feature in assembly code. It can prevent typos in processor feature check.
279 lines
7.0 KiB
ArmAsm
279 lines
7.0 KiB
ArmAsm
/* strrchr with SSE4.2
|
|
Copyright (C) 2009 Free Software Foundation, Inc.
|
|
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 strrchr before the initialization
|
|
happened. */
|
|
#if defined SHARED && !defined NOT_IN_libc
|
|
.text
|
|
ENTRY(strrchr)
|
|
.type strrchr, @gnu_indirect_function
|
|
cmpl $0, __cpu_features+KIND_OFFSET(%rip)
|
|
jne 1f
|
|
call __init_cpu_features
|
|
1: leaq __strrchr_sse2(%rip), %rax
|
|
testl $bit_SSE4_2, __cpu_features+CPUID_OFFSET+index_SSE4_2(%rip)
|
|
jz 2f
|
|
leaq __strrchr_sse42(%rip), %rax
|
|
2: ret
|
|
END(strrchr)
|
|
|
|
/*
|
|
This implementation uses SSE4 instructions to compare up to 16 bytes
|
|
at a time looking for the last occurrence of the character c in the
|
|
string s:
|
|
|
|
char *strrchr (const char *s, int c);
|
|
|
|
We use 0x4a:
|
|
_SIDD_SBYTE_OPS
|
|
| _SIDD_CMP_EQUAL_EACH
|
|
| _SIDD_MOST_SIGNIFICANT
|
|
on pcmpistri to compare xmm/mem128
|
|
|
|
0 1 2 3 4 5 6 7 8 9 A B C D E F
|
|
X X X X X X X X X X X X X X X X
|
|
|
|
against xmm
|
|
|
|
0 1 2 3 4 5 6 7 8 9 A B C D E F
|
|
C C C C C C C C C C C C C C C C
|
|
|
|
to find out if the first 16byte data element has a byte C and the
|
|
last offset. There are 4 cases:
|
|
|
|
1. The first 16byte data element has EOS and has the byte C at the
|
|
last offset X.
|
|
2. The first 16byte data element is valid and has the byte C at the
|
|
last offset X.
|
|
3. The first 16byte data element has EOS and doesn't have the byte C.
|
|
4. The first 16byte data element is valid and doesn't have the byte C.
|
|
|
|
Here is the table of ECX, CFlag, ZFlag and SFlag for 3 cases:
|
|
|
|
case ECX CFlag ZFlag SFlag
|
|
1 X 1 1 0
|
|
2 X 1 0 0
|
|
3 16 0 1 0
|
|
4 16 0 0 0
|
|
|
|
We exit from the loop for cases 1 and 3 with jz which branches
|
|
when ZFlag is 1. If CFlag == 1, ECX has the offset X for case 1. */
|
|
|
|
|
|
.section .text.sse4.2,"ax",@progbits
|
|
.align 16
|
|
.type __strrchr_sse42, @function
|
|
__strrchr_sse42:
|
|
cfi_startproc
|
|
CALL_MCOUNT
|
|
testb %sil, %sil
|
|
je __strend_sse4
|
|
xor %eax,%eax /* RAX has the last occurrence of s. */
|
|
movd %esi, %xmm1
|
|
punpcklbw %xmm1, %xmm1
|
|
movl %edi, %esi
|
|
punpcklbw %xmm1, %xmm1
|
|
andl $15, %esi
|
|
pshufd $0, %xmm1, %xmm1
|
|
movq %rdi, %r8
|
|
je L(loop)
|
|
|
|
/* Handle unaligned string using psrldq. */
|
|
leaq L(psrldq_table)(%rip), %rdx
|
|
andq $-16, %r8
|
|
movslq (%rdx,%rsi,4),%r9
|
|
movdqa (%r8), %xmm0
|
|
addq %rdx, %r9
|
|
jmp *%r9
|
|
|
|
/* Handle unaligned string with offset 1 using psrldq. */
|
|
.p2align 4
|
|
L(psrldq_1):
|
|
psrldq $1, %xmm0
|
|
|
|
.p2align 4
|
|
L(unaligned_pcmpistri):
|
|
pcmpistri $0x4a, %xmm1, %xmm0
|
|
jnc L(unaligned_no_byte)
|
|
leaq (%rdi,%rcx), %rax
|
|
L(unaligned_no_byte):
|
|
/* Find the length of the unaligned string. */
|
|
pcmpistri $0x3a, %xmm0, %xmm0
|
|
movl $16, %edx
|
|
subl %esi, %edx
|
|
cmpl %ecx, %edx
|
|
/* Return RAX if the unaligned fragment to next 16B already
|
|
contain the NULL terminator. */
|
|
jg L(exit)
|
|
addq $16, %r8
|
|
|
|
/* Loop start on aligned string. */
|
|
.p2align 4
|
|
L(loop):
|
|
pcmpistri $0x4a, (%r8), %xmm1
|
|
jbe L(match_or_eos)
|
|
addq $16, %r8
|
|
jmp L(loop)
|
|
.p2align 4
|
|
L(match_or_eos):
|
|
je L(had_eos)
|
|
L(match_no_eos):
|
|
leaq (%r8,%rcx), %rax
|
|
addq $16, %r8
|
|
jmp L(loop)
|
|
.p2align 4
|
|
L(had_eos):
|
|
jnc L(exit)
|
|
leaq (%r8,%rcx), %rax
|
|
.p2align 4
|
|
L(exit):
|
|
ret
|
|
|
|
/* Handle unaligned string with offset 15 using psrldq. */
|
|
.p2align 4
|
|
L(psrldq_15):
|
|
psrldq $15, %xmm0
|
|
jmp L(unaligned_pcmpistri)
|
|
|
|
/* Handle unaligned string with offset 14 using psrldq. */
|
|
.p2align 4
|
|
L(psrldq_14):
|
|
psrldq $14, %xmm0
|
|
jmp L(unaligned_pcmpistri)
|
|
|
|
/* Handle unaligned string with offset 13 using psrldq. */
|
|
.p2align 4
|
|
L(psrldq_13):
|
|
psrldq $13, %xmm0
|
|
jmp L(unaligned_pcmpistri)
|
|
|
|
/* Handle unaligned string with offset 12 using psrldq. */
|
|
.p2align 4
|
|
L(psrldq_12):
|
|
psrldq $12, %xmm0
|
|
jmp L(unaligned_pcmpistri)
|
|
|
|
/* Handle unaligned string with offset 11 using psrldq. */
|
|
.p2align 4
|
|
L(psrldq_11):
|
|
psrldq $11, %xmm0
|
|
jmp L(unaligned_pcmpistri)
|
|
|
|
/* Handle unaligned string with offset 10 using psrldq. */
|
|
.p2align 4
|
|
L(psrldq_10):
|
|
psrldq $10, %xmm0
|
|
jmp L(unaligned_pcmpistri)
|
|
|
|
/* Handle unaligned string with offset 9 using psrldq. */
|
|
.p2align 4
|
|
L(psrldq_9):
|
|
psrldq $9, %xmm0
|
|
jmp L(unaligned_pcmpistri)
|
|
|
|
/* Handle unaligned string with offset 8 using psrldq. */
|
|
.p2align 4
|
|
L(psrldq_8):
|
|
psrldq $8, %xmm0
|
|
jmp L(unaligned_pcmpistri)
|
|
|
|
/* Handle unaligned string with offset 7 using psrldq. */
|
|
.p2align 4
|
|
L(psrldq_7):
|
|
psrldq $7, %xmm0
|
|
jmp L(unaligned_pcmpistri)
|
|
|
|
/* Handle unaligned string with offset 6 using psrldq. */
|
|
.p2align 4
|
|
L(psrldq_6):
|
|
psrldq $6, %xmm0
|
|
jmp L(unaligned_pcmpistri)
|
|
|
|
/* Handle unaligned string with offset 5 using psrldq. */
|
|
.p2align 4
|
|
L(psrldq_5):
|
|
psrldq $5, %xmm0
|
|
jmp L(unaligned_pcmpistri)
|
|
|
|
/* Handle unaligned string with offset 4 using psrldq. */
|
|
.p2align 4
|
|
L(psrldq_4):
|
|
psrldq $4, %xmm0
|
|
jmp L(unaligned_pcmpistri)
|
|
|
|
/* Handle unaligned string with offset 3 using psrldq. */
|
|
.p2align 4
|
|
L(psrldq_3):
|
|
psrldq $3, %xmm0
|
|
jmp L(unaligned_pcmpistri)
|
|
|
|
/* Handle unaligned string with offset 2 using psrldq. */
|
|
.p2align 4
|
|
L(psrldq_2):
|
|
psrldq $2, %xmm0
|
|
jmp L(unaligned_pcmpistri)
|
|
|
|
cfi_endproc
|
|
.size __strrchr_sse42, .-__strrchr_sse42
|
|
|
|
.section .rodata.sse4.2,"a",@progbits
|
|
.p2align 4
|
|
L(psrldq_table):
|
|
.int L(loop) - L(psrldq_table)
|
|
.int L(psrldq_1) - L(psrldq_table)
|
|
.int L(psrldq_2) - L(psrldq_table)
|
|
.int L(psrldq_3) - L(psrldq_table)
|
|
.int L(psrldq_4) - L(psrldq_table)
|
|
.int L(psrldq_5) - L(psrldq_table)
|
|
.int L(psrldq_6) - L(psrldq_table)
|
|
.int L(psrldq_7) - L(psrldq_table)
|
|
.int L(psrldq_8) - L(psrldq_table)
|
|
.int L(psrldq_9) - L(psrldq_table)
|
|
.int L(psrldq_10) - L(psrldq_table)
|
|
.int L(psrldq_11) - L(psrldq_table)
|
|
.int L(psrldq_12) - L(psrldq_table)
|
|
.int L(psrldq_13) - L(psrldq_table)
|
|
.int L(psrldq_14) - L(psrldq_table)
|
|
.int L(psrldq_15) - L(psrldq_table)
|
|
|
|
|
|
# undef ENTRY
|
|
# define ENTRY(name) \
|
|
.type __strrchr_sse2, @function; \
|
|
.align 16; \
|
|
__strrchr_sse2: cfi_startproc; \
|
|
CALL_MCOUNT
|
|
# undef END
|
|
# define END(name) \
|
|
cfi_endproc; .size __strrchr_sse2, .-__strrchr_sse2
|
|
# undef libc_hidden_builtin_def
|
|
/* It doesn't make sense to send libc-internal strrchr 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_strrchr; __GI_strrchr = __strrchr_sse2
|
|
#endif
|
|
|
|
#include "../strrchr.S"
|