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
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
|
/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* Copyright (c) 2013 ARM Ltd
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the company may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY ARM LTD ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL ARM LTD BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
ENTRY_PRIVATE(MEMCPY_BASE)
.cfi_def_cfa_offset 8
.cfi_rel_offset r0, 0
.cfi_rel_offset lr, 4
// Assumes that n >= 0, and dst, src are valid pointers.
// For any sizes less than 832 use the neon code that doesn't
// care about the src alignment. This avoids any checks
// for src alignment, and offers the best improvement since
// smaller sized copies are dominated by the overhead of
// the pre and post main loop.
// For larger copies, if src and dst cannot both be aligned to
// word boundaries, use the neon code.
// For all other copies, align dst to a double word boundary
// and copy using LDRD/STRD instructions.
cmp r2, #16
blo .L_copy_less_than_16_unknown_align
// TODO: The aligned copy code is extremely slow copying some large
// buffers so always go through the unaligned path for now.
//cmp r2, #832
//bge .L_check_alignment
.L_copy_unknown_alignment:
// Unknown alignment of src and dst.
// Assumes that the first few bytes have already been prefetched.
// Align destination to 128 bits. The mainloop store instructions
// require this alignment or they will throw an exception.
rsb r3, r0, #0
ands r3, r3, #0xF
beq 2f
// Copy up to 15 bytes (count in r3).
sub r2, r2, r3
movs ip, r3, lsl #31
itt mi
ldrbmi lr, [r1], #1
strbmi lr, [r0], #1
itttt cs
ldrbcs ip, [r1], #1
ldrbcs lr, [r1], #1
strbcs ip, [r0], #1
strbcs lr, [r0], #1
movs ip, r3, lsl #29
bge 1f
// Copies 4 bytes, dst 32 bits aligned before, at least 64 bits after.
vld4.8 {d0[0], d1[0], d2[0], d3[0]}, [r1]!
vst4.8 {d0[0], d1[0], d2[0], d3[0]}, [r0, :32]!
1: bcc 2f
// Copies 8 bytes, dst 64 bits aligned before, at least 128 bits after.
vld1.8 {d0}, [r1]!
vst1.8 {d0}, [r0, :64]!
2: // Make sure we have at least 64 bytes to copy.
subs r2, r2, #64
blo 2f
1: // The main loop copies 64 bytes at a time.
vld1.8 {d0 - d3}, [r1]!
vld1.8 {d4 - d7}, [r1]!
pld [r1, #(64*4)]
subs r2, r2, #64
vst1.8 {d0 - d3}, [r0, :128]!
vst1.8 {d4 - d7}, [r0, :128]!
bhs 1b
2: // Fix-up the remaining count and make sure we have >= 32 bytes left.
adds r2, r2, #32
blo 3f
// 32 bytes. These cache lines were already preloaded.
vld1.8 {d0 - d3}, [r1]!
sub r2, r2, #32
vst1.8 {d0 - d3}, [r0, :128]!
3: // Less than 32 left.
add r2, r2, #32
tst r2, #0x10
beq .L_copy_less_than_16_unknown_align
// Copies 16 bytes, destination 128 bits aligned.
vld1.8 {d0, d1}, [r1]!
vst1.8 {d0, d1}, [r0, :128]!
.L_copy_less_than_16_unknown_align:
// Copy up to 15 bytes (count in r2).
movs ip, r2, lsl #29
bcc 1f
vld1.8 {d0}, [r1]!
vst1.8 {d0}, [r0]!
1: bge 2f
vld4.8 {d0[0], d1[0], d2[0], d3[0]}, [r1]!
vst4.8 {d0[0], d1[0], d2[0], d3[0]}, [r0]!
2: // Copy 0 to 4 bytes.
lsls r2, r2, #31
itt ne
ldrbne lr, [r1], #1
strbne lr, [r0], #1
itttt cs
ldrbcs ip, [r1], #1
ldrbcs lr, [r1]
strbcs ip, [r0], #1
strbcs lr, [r0]
pop {r0, pc}
.L_check_alignment:
// If src and dst cannot both be aligned to a word boundary,
// use the unaligned copy version.
eor r3, r0, r1
ands r3, r3, #0x3
bne .L_copy_unknown_alignment
END(MEMCPY_BASE)
ENTRY_PRIVATE(MEMCPY_BASE_ALIGNED)
.cfi_def_cfa_offset 8
.cfi_rel_offset r0, 0
.cfi_rel_offset lr, 4
// To try and improve performance, stack layout changed,
// i.e., not keeping the stack looking like users expect
// (highest numbered register at highest address).
strd r4, r5, [sp, #-8]!
.cfi_adjust_cfa_offset 8
.cfi_rel_offset r4, 0
.cfi_rel_offset r5, 4
strd r6, r7, [sp, #-8]!
.cfi_adjust_cfa_offset 8
.cfi_rel_offset r6, 0
.cfi_rel_offset r7, 0
strd r8, r9, [sp, #-8]!
.cfi_adjust_cfa_offset 8
.cfi_rel_offset r8, 0
.cfi_rel_offset r9, 4
// Optimized for already aligned dst code.
ands ip, r0, #3
bne .L_dst_not_word_aligned
.L_word_aligned:
// Align the destination buffer to 8 bytes, to make sure double
// loads and stores don't cross a cache line boundary,
// as they are then more expensive even if the data is in the cache
// (require two load/store issue cycles instead of one).
// If only one of the buffers is not 8 bytes aligned,
// then it's more important to align dst than src,
// because there is more penalty for stores
// than loads that cross a cacheline boundary.
// This check and realignment are only done if there is >= 832
// bytes to copy.
// Dst is word aligned, but check if it is already double word aligned.
ands r3, r0, #4
beq 1f
ldr r3, [r1], #4
str r3, [r0], #4
sub r2, #4
1: // Can only get here if > 64 bytes to copy, so don't do check r2.
sub r2, #64
2: // Every loop iteration copies 64 bytes.
.irp offset, #0, #8, #16, #24, #32
ldrd r4, r5, [r1, \offset]
strd r4, r5, [r0, \offset]
.endr
ldrd r4, r5, [r1, #40]
ldrd r6, r7, [r1, #48]
ldrd r8, r9, [r1, #56]
// Keep the pld as far from the next load as possible.
// The amount to prefetch was determined experimentally using
// large sizes, and verifying the prefetch size does not affect
// the smaller copies too much.
// WARNING: If the ldrd and strd instructions get too far away
// from each other, performance suffers. Three loads
// in a row is the best tradeoff.
pld [r1, #(64*16)]
strd r4, r5, [r0, #40]
strd r6, r7, [r0, #48]
strd r8, r9, [r0, #56]
add r0, r0, #64
add r1, r1, #64
subs r2, r2, #64
bge 2b
// Fix-up the remaining count and make sure we have >= 32 bytes left.
adds r2, r2, #32
blo 4f
// Copy 32 bytes. These cache lines were already preloaded.
.irp offset, #0, #8, #16, #24
ldrd r4, r5, [r1, \offset]
strd r4, r5, [r0, \offset]
.endr
add r1, r1, #32
add r0, r0, #32
sub r2, r2, #32
4: // Less than 32 left.
add r2, r2, #32
tst r2, #0x10
beq 5f
// Copy 16 bytes.
.irp offset, #0, #8
ldrd r4, r5, [r1, \offset]
strd r4, r5, [r0, \offset]
.endr
add r1, r1, #16
add r0, r0, #16
5: // Copy up to 15 bytes (count in r2).
movs ip, r2, lsl #29
bcc 1f
// Copy 8 bytes.
ldrd r4, r5, [r1], #8
strd r4, r5, [r0], #8
1: bge 2f
// Copy 4 bytes.
ldr r4, [r1], #4
str r4, [r0], #4
2: // Copy 0 to 4 bytes.
lsls r2, r2, #31
itt ne
ldrbne lr, [r1], #1
strbne lr, [r0], #1
itttt cs
ldrbcs ip, [r1], #1
ldrbcs lr, [r1]
strbcs ip, [r0], #1
strbcs lr, [r0]
// Restore registers: optimized pop {r0, pc}
ldrd r8, r9, [sp], #8
ldrd r6, r7, [sp], #8
ldrd r4, r5, [sp], #8
pop {r0, pc}
.L_dst_not_word_aligned:
// Align dst to word.
rsb ip, ip, #4
cmp ip, #2
itt gt
ldrbgt lr, [r1], #1
strbgt lr, [r0], #1
itt ge
ldrbge lr, [r1], #1
strbge lr, [r0], #1
ldrb lr, [r1], #1
strb lr, [r0], #1
sub r2, r2, ip
// Src is guaranteed to be at least word aligned by this point.
b .L_word_aligned
END(MEMCPY_BASE_ALIGNED)
|