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
|
/*
* memset - fill memory with a constant byte
*
* Copyright (c) 2012-2020, Arm Limited.
* SPDX-License-Identifier: MIT
*/
/* Assumptions:
*
* ARMv8-a, AArch64, Advanced SIMD, unaligned accesses.
*
*/
#define dstin x0
#define val x1
#define valw w1
#define count x2
#define dst x3
#define dstend x4
#define zva_val x5
.global memset
.type memset,%function
memset:
dup v0.16B, valw
add dstend, dstin, count
cmp count, 96
b.hi .Lset_long
cmp count, 16
b.hs .Lset_medium
mov val, v0.D[0]
/* Set 0..15 bytes. */
tbz count, 3, 1f
str val, [dstin]
str val, [dstend, -8]
ret
nop
1: tbz count, 2, 2f
str valw, [dstin]
str valw, [dstend, -4]
ret
2: cbz count, 3f
strb valw, [dstin]
tbz count, 1, 3f
strh valw, [dstend, -2]
3: ret
/* Set 17..96 bytes. */
.Lset_medium:
str q0, [dstin]
tbnz count, 6, .Lset96
str q0, [dstend, -16]
tbz count, 5, 1f
str q0, [dstin, 16]
str q0, [dstend, -32]
1: ret
.p2align 4
/* Set 64..96 bytes. Write 64 bytes from the start and
32 bytes from the end. */
.Lset96:
str q0, [dstin, 16]
stp q0, q0, [dstin, 32]
stp q0, q0, [dstend, -32]
ret
.p2align 4
.Lset_long:
and valw, valw, 255
bic dst, dstin, 15
str q0, [dstin]
cmp count, 160
ccmp valw, 0, 0, hs
b.ne .Lno_zva
#ifndef SKIP_ZVA_CHECK
mrs zva_val, dczid_el0
and zva_val, zva_val, 31
cmp zva_val, 4 /* ZVA size is 64 bytes. */
b.ne .Lno_zva
#endif
str q0, [dst, 16]
stp q0, q0, [dst, 32]
bic dst, dst, 63
sub count, dstend, dst /* Count is now 64 too large. */
sub count, count, 128 /* Adjust count and bias for loop. */
.p2align 4
.Lzva_loop:
add dst, dst, 64
dc zva, dst
subs count, count, 64
b.hi .Lzva_loop
stp q0, q0, [dstend, -64]
stp q0, q0, [dstend, -32]
ret
.Lno_zva:
sub count, dstend, dst /* Count is 16 too large. */
sub dst, dst, 16 /* Dst is biased by -32. */
sub count, count, 64 + 16 /* Adjust count and bias for loop. */
.Lno_zva_loop:
stp q0, q0, [dst, 32]
stp q0, q0, [dst, 64]!
subs count, count, 64
b.hi .Lno_zva_loop
stp q0, q0, [dstend, -64]
stp q0, q0, [dstend, -32]
ret
.size memset,.-memset
|
