mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-25 12:11:10 +00:00
126 lines
4.3 KiB
ArmAsm
126 lines
4.3 KiB
ArmAsm
/* strcspn (str, ss) -- Return the length of the initial segment of STR
|
|
which contains no characters from SS.
|
|
For AMD x86-64.
|
|
Copyright (C) 1994-2013 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>.
|
|
Bug fixes by Alan Modra <Alan@SPRI.Levels.UniSA.Edu.Au>.
|
|
Adopted for x86-64 by Andreas Jaeger <aj@suse.de>.
|
|
|
|
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/>. */
|
|
|
|
#include <sysdep.h>
|
|
#include "asm-syntax.h"
|
|
|
|
/* BEWARE: `#ifdef strcspn' means that strcspn is redefined as `strpbrk' */
|
|
#define STRPBRK_P (defined strcspn)
|
|
|
|
.text
|
|
ENTRY (strcspn)
|
|
|
|
movq %rdi, %rdx /* Save SRC. */
|
|
|
|
/* First we create a table with flags for all possible characters.
|
|
For the ASCII (7bit/8bit) or ISO-8859-X character sets which are
|
|
supported by the C string functions we have 256 characters.
|
|
Before inserting marks for the stop characters we clear the whole
|
|
table. */
|
|
movq %rdi, %r8 /* Save value. */
|
|
subq $256, %rsp /* Make space for 256 bytes. */
|
|
cfi_adjust_cfa_offset(256)
|
|
movl $32, %ecx /* 32*8 bytes = 256 bytes. */
|
|
movq %rsp, %rdi
|
|
xorl %eax, %eax /* We store 0s. */
|
|
cld
|
|
rep
|
|
stosq
|
|
|
|
movq %rsi, %rax /* Setup skipset. */
|
|
|
|
/* For understanding the following code remember that %rcx == 0 now.
|
|
Although all the following instruction only modify %cl we always
|
|
have a correct zero-extended 64-bit value in %rcx. */
|
|
|
|
.p2align 4
|
|
L(2): movb (%rax), %cl /* get byte from skipset */
|
|
testb %cl, %cl /* is NUL char? */
|
|
jz L(1) /* yes => start compare loop */
|
|
movb %cl, (%rsp,%rcx) /* set corresponding byte in skipset table */
|
|
|
|
movb 1(%rax), %cl /* get byte from skipset */
|
|
testb $0xff, %cl /* is NUL char? */
|
|
jz L(1) /* yes => start compare loop */
|
|
movb %cl, (%rsp,%rcx) /* set corresponding byte in skipset table */
|
|
|
|
movb 2(%rax), %cl /* get byte from skipset */
|
|
testb $0xff, %cl /* is NUL char? */
|
|
jz L(1) /* yes => start compare loop */
|
|
movb %cl, (%rsp,%rcx) /* set corresponding byte in skipset table */
|
|
|
|
movb 3(%rax), %cl /* get byte from skipset */
|
|
addq $4, %rax /* increment skipset pointer */
|
|
movb %cl, (%rsp,%rcx) /* set corresponding byte in skipset table */
|
|
testb $0xff, %cl /* is NUL char? */
|
|
jnz L(2) /* no => process next dword from skipset */
|
|
|
|
L(1): leaq -4(%rdx), %rax /* prepare loop */
|
|
|
|
/* We use a neat trick for the following loop. Normally we would
|
|
have to test for two termination conditions
|
|
1. a character in the skipset was found
|
|
and
|
|
2. the end of the string was found
|
|
But as a sign that the character is in the skipset we store its
|
|
value in the table. But the value of NUL is NUL so the loop
|
|
terminates for NUL in every case. */
|
|
|
|
.p2align 4
|
|
L(3): addq $4, %rax /* adjust pointer for full loop round */
|
|
|
|
movb (%rax), %cl /* get byte from string */
|
|
cmpb %cl, (%rsp,%rcx) /* is it contained in skipset? */
|
|
je L(4) /* yes => return */
|
|
|
|
movb 1(%rax), %cl /* get byte from string */
|
|
cmpb %cl, (%rsp,%rcx) /* is it contained in skipset? */
|
|
je L(5) /* yes => return */
|
|
|
|
movb 2(%rax), %cl /* get byte from string */
|
|
cmpb %cl, (%rsp,%rcx) /* is it contained in skipset? */
|
|
jz L(6) /* yes => return */
|
|
|
|
movb 3(%rax), %cl /* get byte from string */
|
|
cmpb %cl, (%rsp,%rcx) /* is it contained in skipset? */
|
|
jne L(3) /* no => start loop again */
|
|
|
|
incq %rax /* adjust pointer */
|
|
L(6): incq %rax
|
|
L(5): incq %rax
|
|
|
|
L(4): addq $256, %rsp /* remove skipset */
|
|
cfi_adjust_cfa_offset(-256)
|
|
#if STRPBRK_P
|
|
xorl %edx,%edx
|
|
orb %cl, %cl /* was last character NUL? */
|
|
cmovzq %rdx, %rax /* Yes: return NULL */
|
|
#else
|
|
subq %rdx, %rax /* we have to return the number of valid
|
|
characters, so compute distance to first
|
|
non-valid character */
|
|
#endif
|
|
ret
|
|
END (strcspn)
|
|
libc_hidden_builtin_def (strcspn)
|