mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-02 01:40:07 +00:00
155 lines
4.2 KiB
ArmAsm
155 lines
4.2 KiB
ArmAsm
/* Multiple versions of strlen
|
|
Copyright (C) 2009 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, 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
|
|
.section .gnu.linkonce.t.__i686.get_pc_thunk.bx,"ax",@progbits
|
|
.globl __i686.get_pc_thunk.bx
|
|
.hidden __i686.get_pc_thunk.bx
|
|
.p2align 4
|
|
.type __i686.get_pc_thunk.bx,@function
|
|
__i686.get_pc_thunk.bx:
|
|
movl (%esp), %ebx
|
|
ret
|
|
|
|
.text
|
|
ENTRY(strlen)
|
|
.type strlen, @gnu_indirect_function
|
|
pushl %ebx
|
|
cfi_adjust_cfa_offset (4)
|
|
cfi_rel_offset (ebx, 0)
|
|
call __i686.get_pc_thunk.bx
|
|
addl $_GLOBAL_OFFSET_TABLE_, %ebx
|
|
cmpl $0, KIND_OFFSET+__cpu_features@GOTOFF(%ebx)
|
|
jne 1f
|
|
call __init_cpu_features
|
|
1: leal __strlen_ia32@GOTOFF(%ebx), %eax
|
|
testl $bit_SSE2, CPUID_OFFSET+index_SSE2+__cpu_features@GOTOFF(%ebx)
|
|
jz 2f
|
|
leal __strlen_sse2@GOTOFF(%ebx), %eax
|
|
2: popl %ebx
|
|
cfi_adjust_cfa_offset (-4);
|
|
cfi_restore (ebx)
|
|
ret
|
|
END(strlen)
|
|
|
|
#define CFI_POP(REG) \
|
|
cfi_adjust_cfa_offset (-4); \
|
|
cfi_restore (REG)
|
|
|
|
#define RETURN popl %esi; CFI_POP (esi); ret
|
|
|
|
.text
|
|
ENTRY (__strlen_sse2)
|
|
/*
|
|
* This implementation uses SSE instructions to compare up to 16 bytes
|
|
* at a time looking for the end of string (null char).
|
|
*/
|
|
pushl %esi
|
|
cfi_adjust_cfa_offset (4)
|
|
cfi_rel_offset (%esi, 0)
|
|
mov 8(%esp), %eax
|
|
mov %eax, %ecx
|
|
pxor %xmm0, %xmm0 /* 16 null chars */
|
|
mov %eax, %esi
|
|
and $15, %ecx
|
|
jz 1f /* string is 16 byte aligned */
|
|
|
|
/*
|
|
* Unaligned case. Round down to 16-byte boundary before comparing
|
|
* 16 bytes for a null char. The code then compensates for any extra chars
|
|
* preceding the start of the string.
|
|
*/
|
|
and $-16, %esi
|
|
|
|
pcmpeqb (%esi), %xmm0
|
|
lea 16(%eax), %esi
|
|
pmovmskb %xmm0, %edx
|
|
|
|
shr %cl, %edx /* Compensate for bytes preceding the string */
|
|
test %edx, %edx
|
|
jnz 2f
|
|
sub %ecx, %esi /* no null, adjust to next 16-byte boundary */
|
|
pxor %xmm0, %xmm0 /* clear xmm0, may have been changed... */
|
|
|
|
.p2align 4
|
|
1: /* 16 byte aligned */
|
|
pcmpeqb (%esi), %xmm0 /* look for null bytes */
|
|
pmovmskb %xmm0, %edx /* move each byte mask of %xmm0 to edx */
|
|
|
|
add $16, %esi /* prepare to search next 16 bytes */
|
|
test %edx, %edx /* if no null byte, %edx must be 0 */
|
|
jnz 2f /* found a null */
|
|
|
|
pcmpeqb (%esi), %xmm0
|
|
pmovmskb %xmm0, %edx
|
|
add $16, %esi
|
|
test %edx, %edx
|
|
jnz 2f
|
|
|
|
pcmpeqb (%esi), %xmm0
|
|
pmovmskb %xmm0, %edx
|
|
add $16, %esi
|
|
test %edx, %edx
|
|
jnz 2f
|
|
|
|
pcmpeqb (%esi), %xmm0
|
|
pmovmskb %xmm0, %edx
|
|
add $16, %esi
|
|
test %edx, %edx
|
|
jz 1b
|
|
|
|
2:
|
|
neg %eax
|
|
lea -16(%eax, %esi), %eax /* calculate exact offset */
|
|
bsf %edx, %ecx /* Least significant 1 bit is index of null */
|
|
add %ecx, %eax
|
|
popl %esi
|
|
cfi_adjust_cfa_offset (-4)
|
|
cfi_restore (%esi)
|
|
ret
|
|
|
|
END (__strlen_sse2)
|
|
|
|
# undef ENTRY
|
|
# define ENTRY(name) \
|
|
.type __strlen_ia32, @function; \
|
|
.globl __strlen_ia32; \
|
|
.p2align 4; \
|
|
__strlen_ia32: cfi_startproc; \
|
|
CALL_MCOUNT
|
|
# undef END
|
|
# define END(name) \
|
|
cfi_endproc; .size __strlen_ia32, .-__strlen_ia32
|
|
# undef libc_hidden_builtin_def
|
|
/* IFUNC doesn't work with the hidden functions in shared library since
|
|
they will be called without setting up EBX needed for PLT which is
|
|
used by IFUNC. */
|
|
# define libc_hidden_builtin_def(name) \
|
|
.globl __GI_strlen; __GI_strlen = __strlen_ia32
|
|
#endif
|
|
|
|
#include "../../i586/strlen.S"
|