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/* Optimized strncmp 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 STRNCMP __strncmp_aligned
#else
# define STRNCMP strncmp
#endif
LEAF(STRNCMP, 6)
beqz a2, L(ret0)
lu12i.w a5, 0x01010
andi a3, a0, 0x7
ori a5, a5, 0x101
andi a4, a1, 0x7
bstrins.d a5, a5, 63, 32
li.d t7, -1
li.d t8, 8
addi.d a2, a2, -1
slli.d a6, a5, 7
bne a3, a4, L(unaligned)
bstrins.d a0, zero, 2, 0
bstrins.d a1, zero, 2, 0
ld.d t0, a0, 0
ld.d t1, a1, 0
slli.d t2, a3, 3
sub.d t5, t8, a3
srl.d t3, t7, t2
srl.d t0, t0, t2
srl.d t1, t1, t2
orn t0, t0, t3
orn t1, t1, t3
sub.d t2, t0, a5
andn t3, a6, t0
and t2, t2, t3
bne t0, t1, L(al_end)
sltu t4, a2, t5
sub.d a2, a2, t5
L(al_loop):
or t4, t2, t4
bnez t4, L(ret0)
ldx.d t0, a0, t8
ldx.d t1, a1, t8
addi.d t8, t8, 8
sltui t4, a2, 8
addi.d a2, a2, -8
sub.d t2, t0, a5
andn t3, a6, t0
and t2, t2, t3
beq t0, t1, L(al_loop)
addi.d a2, a2, 8
L(al_end):
xor t3, t0, t1
or t2, t2, t3
ctz.d t2, t2
srli.d t4, t2, 3
bstrins.d t2, zero, 2, 0
srl.d t0, t0, t2
srl.d t1, t1, t2
andi t0, t0, 0xff
andi t1, t1, 0xff
sltu t2, a2, t4
sub.d a0, t0, t1
masknez a0, a0, t2
jr ra
L(ret0):
move a0, zero
jr ra
nop
L(unaligned):
slt a7, a4, a3
xor t0, a0, a1
maskeqz t0, t0, a7
xor a0, a0, t0
xor a1, a1, t0
andi a3, a0, 0x7
andi a4, a1, 0x7
bstrins.d a0, zero, 2, 0
bstrins.d a1, zero, 2, 0
ld.d t4, a0, 0
ld.d t1, a1, 0
slli.d t2, a3, 3
slli.d t3, a4, 3
srl.d t5, t7, t3
srl.d t0, t4, t2
srl.d t1, t1, t3
orn t0, t0, t5
orn t1, t1, t5
bne t0, t1, L(not_equal)
sub.d t6, t8, a4
sub.d a4, t2, t3
sll.d t2, t7, t2
sub.d t5, t8, a3
orn t4, t4, t2
sub.d t2, t4, a5
andn t3, a6, t4
sltu t7, a2, t5
and t2, t2, t3
sub.d a3, zero, a4
or t2, t2, t7
bnez t2, L(un_end)
sub.d t7, t5, t6
sub.d a2, a2, t5
sub.d t6, t8, t7
L(un_loop):
srl.d t5, t4, a4
ldx.d t4, a0, t8
ldx.d t1, a1, t8
addi.d t8, t8, 8
sll.d t0, t4, a3
or t0, t0, t5
bne t0, t1, L(loop_not_equal)
sub.d t2, t4, a5
andn t3, a6, t4
sltui t5, a2, 8
and t2, t2, t3
addi.d a2, a2, -8
or t3, t2, t5
beqz t3, L(un_loop)
addi.d a2, a2, 8
L(un_end):
sub.d t2, t0, a5
andn t3, a6, t0
sltu t5, a2, t6
and t2, t2, t3
or t2, t2, t5
bnez t2, L(ret0)
ldx.d t1, a1, t8
srl.d t0, t4, a4
sub.d a2, a2, t6
L(not_equal):
sub.d t2, t0, a5
andn t3, a6, t0
xor t4, t0, t1
and t2, t2, t3
or t2, t2, t4
ctz.d t2, t2
bstrins.d t2, zero, 2, 0
srli.d t4, t2, 3
srl.d t0, t0, t2
srl.d t1, t1, t2
andi t0, t0, 0xff
andi t1, t1, 0xff
sub.d t2, t0, t1
sub.d t3, t1, t0
masknez t0, t2, a7
maskeqz t1, t3, a7
sltu t2, a2, t4
or a0, t0, t1
masknez a0, a0, t2
jr ra
L(loop_not_equal):
add.d a2, a2, t7
b L(not_equal)
END(STRNCMP)
libc_hidden_builtin_def (STRNCMP)
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