aboutsummaryrefslogtreecommitdiff
path: root/sysdeps/aarch64/memset.S
blob: 4a454593618f78e22c55520d56737fab5d8f63a4 (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
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
/* Copyright (C) 2012-2018 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
   <http://www.gnu.org/licenses/>.  */

#include <sysdep.h>
#include "memset-reg.h"

#ifndef MEMSET
# define MEMSET memset
#endif

/* Assumptions:
 *
 * ARMv8-a, AArch64, unaligned accesses
 *
 */

ENTRY_ALIGN (MEMSET, 6)

	DELOUSE (0)
	DELOUSE (2)

	dup	v0.16B, valw
	add	dstend, dstin, count

	cmp	count, 96
	b.hi	L(set_long)
	cmp	count, 16
	b.hs	L(set_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.  */
L(set_medium):
	str	q0, [dstin]
	tbnz	count, 6, L(set96)
	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.  */
L(set96):
	str	q0, [dstin, 16]
	stp	q0, q0, [dstin, 32]
	stp	q0, q0, [dstend, -32]
	ret

	.p2align 3
	nop
L(set_long):
	and	valw, valw, 255
	bic	dst, dstin, 15
	str	q0, [dstin]
	cmp	count, 256
	ccmp	valw, 0, 0, cs
	b.eq	L(try_zva)
L(no_zva):
	sub	count, dstend, dst	/* Count is 16 too large.  */
	add	dst, dst, 16
	sub	count, count, 64 + 16	/* Adjust count and bias for loop.  */
1:	stp	q0, q0, [dst], 64
	stp	q0, q0, [dst, -32]
L(tail64):
	subs	count, count, 64
	b.hi	1b
2:	stp	q0, q0, [dstend, -64]
	stp	q0, q0, [dstend, -32]
	ret

L(try_zva):
#ifdef ZVA_MACRO
	zva_macro
#else
	.p2align 3
	mrs	tmp1, dczid_el0
	tbnz	tmp1w, 4, L(no_zva)
	and	tmp1w, tmp1w, 15
	cmp	tmp1w, 4	/* ZVA size is 64 bytes.  */
	b.ne	 L(zva_128)

	/* Write the first and last 64 byte aligned block using stp rather
	   than using DC ZVA.  This is faster on some cores.
	 */
L(zva_64):
	str	q0, [dst, 16]
	stp	q0, q0, [dst, 32]
	bic	dst, dst, 63
	stp	q0, q0, [dst, 64]
	stp	q0, q0, [dst, 96]
	sub	count, dstend, dst	/* Count is now 128 too large.	*/
	sub	count, count, 128+64+64	/* Adjust count and bias for loop.  */
	add	dst, dst, 128
	nop
1:	dc	zva, dst
	add	dst, dst, 64
	subs	count, count, 64
	b.hi	1b
	stp	q0, q0, [dst, 0]
	stp	q0, q0, [dst, 32]
	stp	q0, q0, [dstend, -64]
	stp	q0, q0, [dstend, -32]
	ret

	.p2align 3
L(zva_128):
	cmp	tmp1w, 5	/* ZVA size is 128 bytes.  */
	b.ne	L(zva_other)

	str	q0, [dst, 16]
	stp	q0, q0, [dst, 32]
	stp	q0, q0, [dst, 64]
	stp	q0, q0, [dst, 96]
	bic	dst, dst, 127
	sub	count, dstend, dst	/* Count is now 128 too large.	*/
	sub	count, count, 128+128	/* Adjust count and bias for loop.  */
	add	dst, dst, 128
1:	dc	zva, dst
	add	dst, dst, 128
	subs	count, count, 128
	b.hi	1b
	stp	q0, q0, [dstend, -128]
	stp	q0, q0, [dstend, -96]
	stp	q0, q0, [dstend, -64]
	stp	q0, q0, [dstend, -32]
	ret

L(zva_other):
	mov	tmp2w, 4
	lsl	zva_lenw, tmp2w, tmp1w
	add	tmp1, zva_len, 64	/* Max alignment bytes written.	 */
	cmp	count, tmp1
	blo	L(no_zva)

	sub	tmp2, zva_len, 1
	add	tmp1, dst, zva_len
	add	dst, dst, 16
	subs	count, tmp1, dst	/* Actual alignment bytes to write.  */
	bic	tmp1, tmp1, tmp2	/* Aligned dc zva start address.  */
	beq	2f
1:	stp	q0, q0, [dst], 64
	stp	q0, q0, [dst, -32]
	subs	count, count, 64
	b.hi	1b
2:	mov	dst, tmp1
	sub	count, dstend, tmp1	/* Remaining bytes to write.  */
	subs	count, count, zva_len
	b.lo	4f
3:	dc	zva, dst
	add	dst, dst, zva_len
	subs	count, count, zva_len
	b.hs	3b
4:	add	count, count, zva_len
	b	L(tail64)
#endif

END (MEMSET)
libc_hidden_builtin_def (MEMSET)