linux/arch/csky/abiv2/strlen.S
Guo Ren c5af58b769 csky: Library functions
This patch adds string optimize codes and some auxiliary codes.

Signed-off-by: Chen Linfei <linfei_chen@c-sky.com>
Signed-off-by: Mao Han <han_mao@c-sky.com>
Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
2018-10-26 00:54:24 +08:00

98 lines
1.4 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0 */
// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
#include <linux/linkage.h>
#include "sysdep.h"
ENTRY(strlen)
/* Check if the start addr is aligned. */
mov r3, r0
andi r1, r0, 3
movi r2, 4
movi r0, 0
bnez r1, .L_start_not_aligned
LABLE_ALIGN
.L_start_addr_aligned:
/* Check if all the bytes in the word are not zero. */
ldw r1, (r3)
tstnbz r1
bf .L_string_tail
ldw r1, (r3, 4)
addi r0, 4
tstnbz r1
bf .L_string_tail
ldw r1, (r3, 8)
addi r0, 4
tstnbz r1
bf .L_string_tail
ldw r1, (r3, 12)
addi r0, 4
tstnbz r1
bf .L_string_tail
ldw r1, (r3, 16)
addi r0, 4
tstnbz r1
bf .L_string_tail
ldw r1, (r3, 20)
addi r0, 4
tstnbz r1
bf .L_string_tail
ldw r1, (r3, 24)
addi r0, 4
tstnbz r1
bf .L_string_tail
ldw r1, (r3, 28)
addi r0, 4
tstnbz r1
bf .L_string_tail
addi r0, 4
addi r3, 32
br .L_start_addr_aligned
.L_string_tail:
# ifdef __CSKYBE__
xtrb0 r3, r1
bez r3, .L_return
addi r0, 1
xtrb1 r3, r1
bez r3, .L_return
addi r0, 1
xtrb2 r3, r1
bez r3, .L_return
addi r0, 1
# else
xtrb3 r3, r1
bez r3, .L_return
addi r0, 1
xtrb2 r3, r1
bez r3, .L_return
addi r0, 1
xtrb1 r3, r1
bez r3, .L_return
addi r0, 1
# endif /* !__CSKYBE__ */
.L_return:
rts
.L_start_not_aligned:
sub r2, r2, r1
.L_start_not_aligned_loop:
ldb r1, (r3)
PRE_BNEZAD (r2)
addi r3, 1
bez r1, .L_return
addi r0, 1
BNEZAD (r2, .L_start_not_aligned_loop)
br .L_start_addr_aligned
ENDPROC(strlen)