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
|
/* Copyright (C) 2012-2014 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/>. */
/* Assumptions:
*
* ARMv8-a, AArch64
* Unaligned accesses
*
*/
#define dstin x0
#define src x1
#define count x2
#define tmp1 x3
#define tmp1w w3
#define tmp2 x4
#define tmp2w w4
#define tmp3 x5
#define tmp3w w5
#define dst x6
#define A_l x7
#define A_h x8
#define B_l x9
#define B_h x10
#define C_l x11
#define C_h x12
#define D_l x13
#define D_h x14
#include <sysdep.h>
ENTRY_ALIGN (memcpy, 6)
mov dst, dstin
cmp count, #64
b.ge L(cpy_not_short)
cmp count, #15
b.le L(tail15tiny)
/* Deal with small copies quickly by dropping straight into the
* exit block. */
L(tail63):
/* Copy up to 48 bytes of data. At this point we only need the
* bottom 6 bits of count to be accurate. */
ands tmp1, count, #0x30
b.eq L(tail15)
add dst, dst, tmp1
add src, src, tmp1
cmp tmp1w, #0x20
b.eq 1f
b.lt 2f
ldp A_l, A_h, [src, #-48]
stp A_l, A_h, [dst, #-48]
1:
ldp A_l, A_h, [src, #-32]
stp A_l, A_h, [dst, #-32]
2:
ldp A_l, A_h, [src, #-16]
stp A_l, A_h, [dst, #-16]
L(tail15):
ands count, count, #15
beq 1f
add src, src, count
ldp A_l, A_h, [src, #-16]
add dst, dst, count
stp A_l, A_h, [dst, #-16]
1:
RET
L(tail15tiny):
/* Copy up to 15 bytes of data. Does not assume additional data
being copied. */
tbz count, #3, 1f
ldr tmp1, [src], #8
str tmp1, [dst], #8
1:
tbz count, #2, 1f
ldr tmp1w, [src], #4
str tmp1w, [dst], #4
1:
tbz count, #1, 1f
ldrh tmp1w, [src], #2
strh tmp1w, [dst], #2
1:
tbz count, #0, 1f
ldrb tmp1w, [src]
strb tmp1w, [dst]
1:
RET
L(cpy_not_short):
/* We don't much care about the alignment of DST, but we want SRC
* to be 128-bit (16 byte) aligned so that we don't cross cache line
* boundaries on both loads and stores. */
neg tmp2, src
ands tmp2, tmp2, #15 /* Bytes to reach alignment. */
b.eq 2f
sub count, count, tmp2
/* Copy more data than needed; it's faster than jumping
* around copying sub-Quadword quantities. We know that
* it can't overrun. */
ldp A_l, A_h, [src]
add src, src, tmp2
stp A_l, A_h, [dst]
add dst, dst, tmp2
/* There may be less than 63 bytes to go now. */
cmp count, #63
b.le L(tail63)
2:
subs count, count, #128
b.ge L(cpy_body_large)
/* Less than 128 bytes to copy, so handle 64 here and then jump
* to the tail. */
ldp A_l, A_h, [src]
ldp B_l, B_h, [src, #16]
ldp C_l, C_h, [src, #32]
ldp D_l, D_h, [src, #48]
stp A_l, A_h, [dst]
stp B_l, B_h, [dst, #16]
stp C_l, C_h, [dst, #32]
stp D_l, D_h, [dst, #48]
tst count, #0x3f
add src, src, #64
add dst, dst, #64
b.ne L(tail63)
RET
/* Critical loop. Start at a new cache line boundary. Assuming
* 64 bytes per line this ensures the entire loop is in one line. */
.p2align 6
L(cpy_body_large):
/* There are at least 128 bytes to copy. */
ldp A_l, A_h, [src, #0]
sub dst, dst, #16 /* Pre-bias. */
ldp B_l, B_h, [src, #16]
ldp C_l, C_h, [src, #32]
ldp D_l, D_h, [src, #48]! /* src += 64 - Pre-bias. */
1:
stp A_l, A_h, [dst, #16]
ldp A_l, A_h, [src, #16]
stp B_l, B_h, [dst, #32]
ldp B_l, B_h, [src, #32]
stp C_l, C_h, [dst, #48]
ldp C_l, C_h, [src, #48]
stp D_l, D_h, [dst, #64]!
ldp D_l, D_h, [src, #64]!
subs count, count, #64
b.ge 1b
stp A_l, A_h, [dst, #16]
stp B_l, B_h, [dst, #32]
stp C_l, C_h, [dst, #48]
stp D_l, D_h, [dst, #64]
add src, src, #16
add dst, dst, #64 + 16
tst count, #0x3f
b.ne L(tail63)
RET
END (memcpy)
libc_hidden_builtin_def (memcpy)
|
