mirror of
git://sourceware.org/git/glibc.git
synced 2024-11-27 03:41:23 +08:00
2b778ceb40
I used these shell commands: ../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright (cd ../glibc && git commit -am"[this commit message]") and then ignored the output, which consisted lines saying "FOO: warning: copyright statement not found" for each of 6694 files FOO. I then removed trailing white space from benchtests/bench-pthread-locks.c and iconvdata/tst-iconv-big5-hkscs-to-2ucs4.c, to work around this diagnostic from Savannah: remote: *** pre-commit check failed ... remote: *** error: lines with trailing whitespace found remote: error: hook declined to update refs/heads/master
120 lines
3.3 KiB
ArmAsm
120 lines
3.3 KiB
ArmAsm
/* strchr - find a character in a string
|
|
|
|
Copyright (C) 2014-2021 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, see
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
#include <sysdep.h>
|
|
|
|
/* Assumptions:
|
|
*
|
|
* ARMv8-a, AArch64, Advanced SIMD.
|
|
* MTE compatible.
|
|
*/
|
|
|
|
#define srcin x0
|
|
#define chrin w1
|
|
#define result x0
|
|
|
|
#define src x2
|
|
#define tmp1 x1
|
|
#define wtmp2 w3
|
|
#define tmp3 x3
|
|
|
|
#define vrepchr v0
|
|
#define vdata v1
|
|
#define qdata q1
|
|
#define vhas_nul v2
|
|
#define vhas_chr v3
|
|
#define vrepmask v4
|
|
#define vrepmask2 v5
|
|
#define vend v6
|
|
#define dend d6
|
|
|
|
/* Core algorithm.
|
|
|
|
For each 16-byte chunk we calculate a 64-bit syndrome value with four bits
|
|
per byte. For even bytes, bits 0-1 are set if the relevant byte matched the
|
|
requested character, bits 2-3 are set if the byte is NUL (or matched), and
|
|
bits 4-7 are not used and must be zero if none of bits 0-3 are set). Odd
|
|
bytes set bits 4-7 so that adjacent bytes can be merged. Since the bits
|
|
in the syndrome reflect the order in which things occur in the original
|
|
string, counting trailing zeros identifies exactly which byte matched. */
|
|
|
|
ENTRY (strchr)
|
|
PTR_ARG (0)
|
|
bic src, srcin, 15
|
|
dup vrepchr.16b, chrin
|
|
ld1 {vdata.16b}, [src]
|
|
mov wtmp2, 0x3003
|
|
dup vrepmask.8h, wtmp2
|
|
cmeq vhas_nul.16b, vdata.16b, 0
|
|
cmeq vhas_chr.16b, vdata.16b, vrepchr.16b
|
|
mov wtmp2, 0xf00f
|
|
dup vrepmask2.8h, wtmp2
|
|
|
|
bit vhas_nul.16b, vhas_chr.16b, vrepmask.16b
|
|
and vhas_nul.16b, vhas_nul.16b, vrepmask2.16b
|
|
lsl tmp3, srcin, 2
|
|
addp vend.16b, vhas_nul.16b, vhas_nul.16b /* 128->64 */
|
|
|
|
fmov tmp1, dend
|
|
lsr tmp1, tmp1, tmp3
|
|
cbz tmp1, L(loop)
|
|
|
|
rbit tmp1, tmp1
|
|
clz tmp1, tmp1
|
|
/* Tmp1 is an even multiple of 2 if the target character was
|
|
found first. Otherwise we've found the end of string. */
|
|
tst tmp1, 2
|
|
add result, srcin, tmp1, lsr 2
|
|
csel result, result, xzr, eq
|
|
ret
|
|
|
|
.p2align 4
|
|
L(loop):
|
|
ldr qdata, [src, 16]!
|
|
cmeq vhas_chr.16b, vdata.16b, vrepchr.16b
|
|
cmhs vhas_nul.16b, vhas_chr.16b, vdata.16b
|
|
umaxp vend.16b, vhas_nul.16b, vhas_nul.16b
|
|
fmov tmp1, dend
|
|
cbz tmp1, L(loop)
|
|
|
|
#ifdef __AARCH64EB__
|
|
bif vhas_nul.16b, vhas_chr.16b, vrepmask.16b
|
|
and vhas_nul.16b, vhas_nul.16b, vrepmask2.16b
|
|
addp vend.16b, vhas_nul.16b, vhas_nul.16b /* 128->64 */
|
|
fmov tmp1, dend
|
|
#else
|
|
bit vhas_nul.16b, vhas_chr.16b, vrepmask.16b
|
|
and vhas_nul.16b, vhas_nul.16b, vrepmask2.16b
|
|
addp vend.16b, vhas_nul.16b, vhas_nul.16b /* 128->64 */
|
|
fmov tmp1, dend
|
|
rbit tmp1, tmp1
|
|
#endif
|
|
clz tmp1, tmp1
|
|
/* Tmp1 is an even multiple of 2 if the target character was
|
|
found first. Otherwise we've found the end of string. */
|
|
tst tmp1, 2
|
|
add result, src, tmp1, lsr 2
|
|
csel result, result, xzr, eq
|
|
ret
|
|
|
|
END (strchr)
|
|
libc_hidden_builtin_def (strchr)
|
|
weak_alias (strchr, index)
|