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/* Optimized strlen implementation using basic Loongarch instructions.
Copyright (C) 2023 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>
#include <sys/regdef.h>
#include <sys/asm.h>
#if IS_IN (libc)
# define STRLEN __strlen_aligned
#else
# define STRLEN strlen
#endif
LEAF(STRLEN, 6)
move a1, a0
bstrins.d a0, zero, 2, 0
lu12i.w a2, 0x01010
li.w t0, -1
ld.d t2, a0, 0
andi t1, a1, 0x7
ori a2, a2, 0x101
slli.d t1, t1, 3
bstrins.d a2, a2, 63, 32
sll.d t1, t0, t1
slli.d t3, a2, 7
nor a3, zero, t3
orn t2, t2, t1
sub.d t0, t2, a2
nor t1, t2, a3
and t0, t0, t1
bnez t0, L(count_pos)
addi.d a0, a0, 8
L(loop_16_7bit):
ld.d t2, a0, 0
sub.d t1, t2, a2
and t0, t1, t3
bnez t0, L(more_check)
ld.d t2, a0, 8
sub.d t1, t2, a2
and t0, t1, t3
addi.d a0, a0, 16
beqz t0, L(loop_16_7bit)
addi.d a0, a0, -8
L(more_check):
nor t0, t2, a3
and t0, t1, t0
bnez t0, L(count_pos)
addi.d a0, a0, 8
L(loop_16_8bit):
ld.d t2, a0, 0
sub.d t1, t2, a2
nor t0, t2, a3
and t0, t0, t1
bnez t0, L(count_pos)
ld.d t2, a0, 8
addi.d a0, a0, 16
sub.d t1, t2, a2
nor t0, t2, a3
and t0, t0, t1
beqz t0, L(loop_16_8bit)
addi.d a0, a0, -8
L(count_pos):
ctz.d t1, t0
sub.d a0, a0, a1
srli.d t1, t1, 3
add.d a0, a0, t1
jr ra
END(STRLEN)
libc_hidden_builtin_def (STRLEN)
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