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/* The assembly function for memory compare. C-SKY ABIV2 version.
Copyright (C) 2018-2020 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 (memcmp)
/* Test if len less than 4 bytes. */
mov r3, r0
movi r0, 0
mov r12, r4
cmplti r2, 4
jbt .L_compare_by_byte
andi r13, r0, 3
movi r19, 4
/* Test if s1 is not 4 bytes aligned. */
bnez r13, .L_s1_not_aligned
LABLE_ALIGN
.L_s1_aligned:
/* If dest is aligned, then copy. */
zext r18, r2, 31, 4
/* Test if len less than 16 bytes. */
bez r18, .L_compare_by_word
.L_compare_by_4word:
/* If aligned, load word each time. */
ldw r20, (r3, 0)
ldw r21, (r1, 0)
/* If s1[i] != s2[i], goto .L_byte_check. */
cmpne r20, r21
bt .L_byte_check
ldw r20, (r3, 4)
ldw r21, (r1, 4)
cmpne r20, r21
bt .L_byte_check
ldw r20, (r3, 8)
ldw r21, (r1, 8)
cmpne r20, r21
bt .L_byte_check
ldw r20, (r3, 12)
ldw r21, (r1, 12)
cmpne r20, r21
bt .L_byte_check
PRE_BNEZAD (r18)
addi a3, 16
addi a1, 16
BNEZAD (r18, .L_compare_by_4word)
.L_compare_by_word:
zext r18, r2, 3, 2
bez r18, .L_compare_by_byte
.L_compare_by_word_loop:
ldw r20, (r3, 0)
ldw r21, (r1, 0)
addi r3, 4
PRE_BNEZAD (r18)
cmpne r20, r21
addi r1, 4
bt .L_byte_check
BNEZAD (r18, .L_compare_by_word_loop)
.L_compare_by_byte:
zext r18, r2, 1, 0
bez r18, .L_return
.L_compare_by_byte_loop:
ldb r0, (r3, 0)
ldb r4, (r1, 0)
addi r3, 1
subu r0, r4
PRE_BNEZAD (r18)
addi r1, 1
bnez r0, .L_return
BNEZAD (r18, .L_compare_by_byte_loop)
.L_return:
mov r4, r12
rts
/* s1[i] != s2[i] in word, so we check byte 3. */
.L_byte_check:
xtrb3 r0, r20
xtrb3 r2, r21
subu r0, r2
bnez r0, .L_return
/* check byte 2 */
xtrb2 r0, r20
xtrb2 r2, r21
subu r0, r2
bnez r0, .L_return
/* check byte 1 */
xtrb1 r0, r20
xtrb1 r2, r21
subu r0, r2
bnez r0, .L_return
/* check byte 0 */
xtrb0 r0, r20
xtrb0 r2, r21
subu r0, r2
br .L_return
/* Compare when s1 is not aligned. */
.L_s1_not_aligned:
sub r13, r19, r13
sub r2, r13
.L_s1_not_aligned_loop:
ldb r0, (r3, 0)
ldb r4, (r1, 0)
addi r3, 1
subu r0, r4
PRE_BNEZAD (r13)
addi r1, 1
bnez r0, .L_return
BNEZAD (r13, .L_s1_not_aligned_loop)
br .L_s1_aligned
END (memcmp)
weak_alias (memcmp, bcmp)
libc_hidden_def (memcmp)
.weak memcmp
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