aboutsummaryrefslogtreecommitdiffstats
path: root/arch/loongarch/lib/memset.S
blob: 06d3ca54cbfe7d73c6cc7a5cadeca4d558b3e6dc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
 */

#include <linux/export.h>
#include <asm/alternative-asm.h>
#include <asm/asm.h>
#include <asm/asmmacro.h>
#include <asm/cpu.h>
#include <asm/regdef.h>

.macro fill_to_64 r0
	bstrins.d \r0, \r0, 15, 8
	bstrins.d \r0, \r0, 31, 16
	bstrins.d \r0, \r0, 63, 32
.endm

.section .noinstr.text, "ax"

SYM_FUNC_START(memset)
	/*
	 * Some CPUs support hardware unaligned access
	 */
	ALTERNATIVE	"b __memset_generic", \
			"b __memset_fast", CPU_FEATURE_UAL
SYM_FUNC_END(memset)
SYM_FUNC_ALIAS(__memset, memset)

EXPORT_SYMBOL(memset)
EXPORT_SYMBOL(__memset)

_ASM_NOKPROBE(memset)
_ASM_NOKPROBE(__memset)

/*
 * void *__memset_generic(void *s, int c, size_t n)
 *
 * a0: s
 * a1: c
 * a2: n
 */
SYM_FUNC_START(__memset_generic)
	move	a3, a0
	beqz	a2, 2f

1:	st.b	a1, a0, 0
	addi.d	a0, a0, 1
	addi.d	a2, a2, -1
	bgt	a2, zero, 1b

2:	move	a0, a3
	jr	ra
SYM_FUNC_END(__memset_generic)
_ASM_NOKPROBE(__memset_generic)

/*
 * void *__memset_fast(void *s, int c, size_t n)
 *
 * a0: s
 * a1: c
 * a2: n
 */
SYM_FUNC_START(__memset_fast)
	/* fill a1 to 64 bits */
	fill_to_64 a1

	sltui	t0, a2, 9
	bnez	t0, .Lsmall

	add.d	a2, a0, a2
	st.d	a1, a0, 0

	/* align up address */
	addi.d	a3, a0, 8
	bstrins.d	a3, zero, 2, 0

	addi.d	a4, a2, -64
	bgeu	a3, a4, .Llt64

	/* set 64 bytes at a time */
.Lloop64:
	st.d	a1, a3, 0
	st.d	a1, a3, 8
	st.d	a1, a3, 16
	st.d	a1, a3, 24
	st.d	a1, a3, 32
	st.d	a1, a3, 40
	st.d	a1, a3, 48
	st.d	a1, a3, 56
	addi.d	a3, a3, 64
	bltu	a3, a4, .Lloop64

	/* set the remaining bytes */
.Llt64:
	addi.d	a4, a2, -32
	bgeu	a3, a4, .Llt32
	st.d	a1, a3, 0
	st.d	a1, a3, 8
	st.d	a1, a3, 16
	st.d	a1, a3, 24
	addi.d	a3, a3, 32

.Llt32:
	addi.d	a4, a2, -16
	bgeu	a3, a4, .Llt16
	st.d	a1, a3, 0
	st.d	a1, a3, 8
	addi.d	a3, a3, 16

.Llt16:
	addi.d	a4, a2, -8
	bgeu	a3, a4, .Llt8
	st.d	a1, a3, 0

.Llt8:
	st.d	a1, a2, -8

	/* return */
	jr	ra

	.align	4
.Lsmall:
	pcaddi	t0, 4
	slli.d	a2, a2, 4
	add.d	t0, t0, a2
	jr	t0

	.align	4
0:	jr	ra

	.align	4
1:	st.b	a1, a0, 0
	jr	ra

	.align	4
2:	st.h	a1, a0, 0
	jr	ra

	.align	4
3:	st.h	a1, a0, 0
	st.b	a1, a0, 2
	jr	ra

	.align	4
4:	st.w	a1, a0, 0
	jr	ra

	.align	4
5:	st.w	a1, a0, 0
	st.b	a1, a0, 4
	jr	ra

	.align	4
6:	st.w	a1, a0, 0
	st.h	a1, a0, 4
	jr	ra

	.align	4
7:	st.w	a1, a0, 0
	st.w	a1, a0, 3
	jr	ra

	.align	4
8:	st.d	a1, a0, 0
	jr	ra
SYM_FUNC_END(__memset_fast)
_ASM_NOKPROBE(__memset_fast)