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/* Optimized memcmp 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 MEMCMP_NAME __memcmp_aligned
#else
# define MEMCMP_NAME memcmp
#endif
LEAF(MEMCMP_NAME, 6)
beqz a2, L(ret)
andi a4, a1, 0x7
andi a3, a0, 0x7
sltu a5, a4, a3
xor t0, a0, a1
li.w t8, 8
maskeqz t0, t0, a5
li.w t7, -1
xor a0, a0, t0
xor a1, a1, t0
andi a3, a0, 0x7
andi a4, a1, 0x7
xor a0, a0, a3
xor a1, a1, a4
ld.d t2, a0, 0
ld.d t1, a1, 0
slli.d t3, a3, 3
slli.d t4, a4, 3
sub.d a6, t3, t4
srl.d t1, t1, t4
srl.d t0, t2, t3
srl.d t5, t7, t4
sub.d t6, t0, t1
and t6, t6, t5
sub.d t5, t8, a4
bnez t6, L(first_out)
bgeu t5, a2, L(ret)
sub.d a2, a2, t5
bnez a6, L(unaligned)
blt a2, t8, L(al_less_8bytes)
andi t1, a2, 31
beq t1, a2, L(al_less_32bytes)
sub.d t2, a2, t1
add.d a4, a0, t2
move a2, t1
L(al_loop):
ld.d t0, a0, 8
ld.d t1, a1, 8
ld.d t2, a0, 16
ld.d t3, a1, 16
ld.d t4, a0, 24
ld.d t5, a1, 24
ld.d t6, a0, 32
ld.d t7, a1, 32
addi.d a0, a0, 32
addi.d a1, a1, 32
bne t0, t1, L(out1)
bne t2, t3, L(out2)
bne t4, t5, L(out3)
bne t6, t7, L(out4)
bne a0, a4, L(al_loop)
L(al_less_32bytes):
srai.d a4, a2, 4
beqz a4, L(al_less_16bytes)
ld.d t0, a0, 8
ld.d t1, a1, 8
ld.d t2, a0, 16
ld.d t3, a1, 16
addi.d a0, a0, 16
addi.d a1, a1, 16
addi.d a2, a2, -16
bne t0, t1, L(out1)
bne t2, t3, L(out2)
L(al_less_16bytes):
srai.d a4, a2, 3
beqz a4, L(al_less_8bytes)
ld.d t0, a0, 8
ld.d t1, a1, 8
addi.d a0, a0, 8
addi.d a1, a1, 8
addi.d a2, a2, -8
bne t0, t1, L(out1)
L(al_less_8bytes):
beqz a2, L(ret)
ld.d t0, a0, 8
ld.d t1, a1, 8
li.d t7, -1
slli.d t2, a2, 3
sll.d t2, t7, t2
sub.d t3, t0, t1
andn t6, t3, t2
bnez t6, L(count_diff)
L(ret):
move a0, zero
jr ra
L(out4):
move t0, t6
move t1, t7
sub.d t6, t6, t7
b L(count_diff)
L(out3):
move t0, t4
move t1, t5
sub.d t6, t4, t5
b L(count_diff)
L(out2):
move t0, t2
move t1, t3
L(out1):
sub.d t6, t0, t1
b L(count_diff)
L(first_out):
slli.d t4, a2, 3
slt t3, a2, t5
sll.d t4, t7, t4
maskeqz t4, t4, t3
andn t6, t6, t4
L(count_diff):
ctz.d t2, t6
bstrins.d t2, zero, 2, 0
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 t2, t2, a5
maskeqz t3, t3, a5
or a0, t2, t3
jr ra
L(unaligned):
sub.d a7, zero, a6
srl.d t0, t2, a6
blt a2, t8, L(un_less_8bytes)
andi t1, a2, 31
beq t1, a2, L(un_less_32bytes)
sub.d t2, a2, t1
add.d a4, a0, t2
move a2, t1
L(un_loop):
ld.d t2, a0, 8
ld.d t1, a1, 8
ld.d t4, a0, 16
ld.d t3, a1, 16
ld.d t6, a0, 24
ld.d t5, a1, 24
ld.d t8, a0, 32
ld.d t7, a1, 32
addi.d a0, a0, 32
addi.d a1, a1, 32
sll.d a3, t2, a7
or t0, a3, t0
bne t0, t1, L(out1)
srl.d t0, t2, a6
sll.d a3, t4, a7
or t2, a3, t0
bne t2, t3, L(out2)
srl.d t0, t4, a6
sll.d a3, t6, a7
or t4, a3, t0
bne t4, t5, L(out3)
srl.d t0, t6, a6
sll.d a3, t8, a7
or t6, t0, a3
bne t6, t7, L(out4)
srl.d t0, t8, a6
bne a0, a4, L(un_loop)
L(un_less_32bytes):
srai.d a4, a2, 4
beqz a4, L(un_less_16bytes)
ld.d t2, a0, 8
ld.d t1, a1, 8
ld.d t4, a0, 16
ld.d t3, a1, 16
addi.d a0, a0, 16
addi.d a1, a1, 16
addi.d a2, a2, -16
sll.d a3, t2, a7
or t0, a3, t0
bne t0, t1, L(out1)
srl.d t0, t2, a6
sll.d a3, t4, a7
or t2, a3, t0
bne t2, t3, L(out2)
srl.d t0, t4, a6
L(un_less_16bytes):
srai.d a4, a2, 3
beqz a4, L(un_less_8bytes)
ld.d t2, a0, 8
ld.d t1, a1, 8
addi.d a0, a0, 8
addi.d a1, a1, 8
addi.d a2, a2, -8
sll.d a3, t2, a7
or t0, a3, t0
bne t0, t1, L(out1)
srl.d t0, t2, a6
L(un_less_8bytes):
beqz a2, L(ret)
andi a7, a7, 63
slli.d a4, a2, 3
bgeu a7, a4, L(last_cmp)
ld.d t2, a0, 8
sll.d a3, t2, a7
or t0, a3, t0
L(last_cmp):
ld.d t1, a1, 8
li.d t7, -1
sll.d t2, t7, a4
sub.d t3, t0, t1
andn t6, t3, t2
bnez t6, L(count_diff)
move a0, zero
jr ra
END(MEMCMP_NAME)
libc_hidden_builtin_def (MEMCMP_NAME)
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