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/* The assembly function for string compare. C-SKY ABIV2 version.
Copyright (C) 2018-2021 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>
ENTRY (strcmp)
mov a3, a0
/* Check if the s1 addr is aligned. */
xor a2, a3, a1
andi a2, 0x3
bnez a2, 7f
andi t1, a0, 0x3
bnez t1, 5f
1:
/* If aligned, load word each time. */
ldw t0, (a3, 0)
ldw t1, (a1, 0)
/* If s1[i] != s2[i], goto 2f. */
cmpne t0, t1
bt 2f
/* If s1[i] == s2[i], check if s1 or s2 is at the end. */
tstnbz t0
/* If at the end, goto 3f (finish comparing). */
bf 3f
ldw t0, (a3, 4)
ldw t1, (a1, 4)
cmpne t0, t1
bt 2f
tstnbz t0
bf 3f
ldw t0, (a3, 8)
ldw t1, (a1, 8)
cmpne t0, t1
bt 2f
tstnbz t0
bf 3f
ldw t0, (a3, 12)
ldw t1, (a1, 12)
cmpne t0, t1
bt 2f
tstnbz t0
bf 3f
ldw t0, (a3, 16)
ldw t1, (a1, 16)
cmpne t0, t1
bt 2f
tstnbz t0
bf 3f
ldw t0, (a3, 20)
ldw t1, (a1, 20)
cmpne t0, t1
bt 2f
tstnbz t0
bf 3f
ldw t0, (a3, 24)
ldw t1, (a1, 24)
cmpne t0, t1
bt 2f
tstnbz t0
bf 3f
ldw t0, (a3, 28)
ldw t1, (a1, 28)
cmpne t0, t1
bt 2f
tstnbz t0
bf 3f
addi a3, 32
addi a1, 32
br 1b
/* s1[i] != s2[i] in word, so we check byte 3. */
2:
xtrb3 a0, t0
xtrb3 a2, t1
subu a0, a2
bez a2, 4f
bnez a0, 4f
/* Check byte 2. */
xtrb2 a0, t0
xtrb2 a2, t1
subu a0, a2
bez a2, 4f
bnez a0, 4f
/* Check byte 1. */
xtrb1 a0, t0
xtrb1 a2, t1
subu a0, a2
bez a2, 4f
bnez a0, 4f
/* Check byte 0. */
xtrb0 a0, t0
xtrb0 a2, t1
subu a0, a2
jmp lr
3:
movi a0, 0
4:
jmp lr
/* Compare when s1 or s2 is not aligned. */
5:
subi t1, 4
6:
ldb a0, (a3, 0)
ldb a2, (a1, 0)
subu a0, a2
bnez a0, 4b
addi t1, 1
bez a2, 4b
addi a1, 1
addi a3, 1
bez t1, 1b
br 6b
7:
ldb a0, (a3, 0)
addi a3, 1
ldb a2, (a1, 0)
addi a1, 1
subu a0, a2
bnez a0, 4b
bnez a2, 7b
jmp r15
END (strcmp)
libc_hidden_def (strcmp)
.weak strcmp
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