about summary refs log tree commit diff
path: root/sysdeps/powerpc/powerpc64/le/power10/memmove.S
blob: 3024718fdf52043b4c66cf45b095863f44f65cfa (plain) (blame)
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
/* Optimized memmove implementation for POWER10.
   Copyright (C) 2021-2022 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
   <https://www.gnu.org/licenses/>.  */

#include <sysdep.h>


/* void* [r3] memmove (void *dest [r3], const void *src [r4], size_t len [r5])

   This optimization checks if 'src' and 'dst' overlap.  If they do not
   or 'src' is ahead of 'dest' then it copies forward.
   Otherwise, an optimized backward copy is used.  */

#ifndef MEMMOVE
# define MEMMOVE memmove
#endif
	.machine power9
ENTRY_TOCLESS (MEMMOVE, 5)
	CALL_MCOUNT 3

L(_memmove):
	.p2align 5
	/* Check if there is overlap, if so it will branch to backward copy.  */
	subf	r9,r4,r3
	cmpld	cr7,r9,r5
	blt	cr7,L(memmove_bwd)

	/* Fast path for length shorter than 16 bytes.  */
	sldi	r7,r5,56
	lxvl	32+v2,r4,r7
	stxvl	32+v2,r3,r7
	subic.	r8,r5,16
	blelr

	/* For shorter lengths aligning the dest address to 16 bytes either
	   decreases performance or is irrelevant.  I'm making use of this
	   comparison to skip the alignment in.  */
	cmpldi	cr6,r5,256
	bge	cr6,L(ge_256)
	/* Account for the first 16-byte copy.  */
	addi	r4,r4,16
	addi	r11,r3,16	/* use r11 to keep dest address on r3.  */
	subi	r5,r5,16
	b	L(loop_head)

	.p2align 5
L(ge_256):
	/* Account for the first copy <= 16 bytes.  This is necessary for
	   memmove because at this point the src address can be in front of the
	   dest address.  */
	clrldi	r9,r5,56
	li	r8,16
	cmpldi	r9,16
	iselgt	r9,r8,r9
	add	r4,r4,r9
	add	r11,r3,r9	/* use r11 to keep dest address on r3.  */
	sub	r5,r5,r9

	/* Align dest to 16 bytes.  */
	neg	r7,r3
	clrldi.	r9,r7,60
	beq	L(loop_head)

	.p2align 5
	sldi	r6,r9,56
	lxvl	32+v0,r4,r6
	stxvl	32+v0,r11,r6
	sub	r5,r5,r9
	add	r4,r4,r9
	add	r11,r11,r9

L(loop_head):
	cmpldi	r5,63
	ble	L(final_64)

	srdi.	r7,r5,7
	beq	L(loop_tail)

	mtctr	r7

/* Main loop that copies 128 bytes each iteration.  */
	.p2align 5
L(loop):
	addi	r9,r4,64
	addi	r10,r11,64

	lxv	32+v0,0(r4)
	lxv	32+v1,16(r4)
	lxv	32+v2,32(r4)
	lxv	32+v3,48(r4)

	stxv	32+v0,0(r11)
	stxv	32+v1,16(r11)
	stxv	32+v2,32(r11)
	stxv	32+v3,48(r11)

	addi	r4,r4,128
	addi	r11,r11,128

	lxv	32+v4,0(r9)
	lxv	32+v5,16(r9)
	lxv	32+v6,32(r9)
	lxv	32+v7,48(r9)

	stxv	32+v4,0(r10)
	stxv	32+v5,16(r10)
	stxv	32+v6,32(r10)
	stxv	32+v7,48(r10)

	bdnz	L(loop)
	clrldi.	r5,r5,57
	beqlr

/* Copy 64 bytes.  */
	.p2align 5
L(loop_tail):
	cmpldi 	cr5,r5,63
	ble	cr5,L(final_64)

	lxv	32+v0,0(r4)
	lxv	32+v1,16(r4)
	lxv	32+v2,32(r4)
	lxv	32+v3,48(r4)

	stxv	32+v0,0(r11)
	stxv	32+v1,16(r11)
	stxv	32+v2,32(r11)
	stxv	32+v3,48(r11)

	addi	r4,r4,64
	addi	r11,r11,64
	subi	r5,r5,64

/* Copies the last 1-63 bytes.  */
	.p2align 5
L(final_64):
	/* r8 holds the number of bytes that will be copied with lxv/stxv.  */
	clrrdi.	r8,r5,4
	beq	L(tail1)

	cmpldi  cr5,r5,32
	lxv	32+v0,0(r4)
	blt	cr5,L(tail2)

	cmpldi	cr6,r5,48
	lxv	32+v1,16(r4)
	blt	cr6,L(tail3)

	.p2align 5
	lxv	32+v2,32(r4)
	stxv	32+v2,32(r11)
L(tail3):
	stxv	32+v1,16(r11)
L(tail2):
	stxv	32+v0,0(r11)
	sub	r5,r5,r8
	add	r4,r4,r8
	add	r11,r11,r8
	.p2align 5
L(tail1):
	sldi	r6,r5,56
	lxvl	v4,r4,r6
	stxvl	v4,r11,r6
	blr

/* If dest and src overlap, we should copy backwards.  */
L(memmove_bwd):
	add	r11,r3,r5
	add	r4,r4,r5

	/* Optimization for length smaller than 16 bytes.  */
	cmpldi	cr5,r5,15
	ble	cr5,L(tail1_bwd)

	/* For shorter lengths the alignment either slows down or is irrelevant.
	   The forward copy uses a already need 256 comparison for that.  Here
	   it's using 128 as it will reduce code and improve readability.  */
	cmpldi	cr7,r5,128
	blt	cr7,L(bwd_loop_tail)

	/* Align dest address to 16 bytes.  */
	.p2align 5
	clrldi.	r9,r11,60
	beq	L(bwd_loop_head)
	sub	r4,r4,r9
	sub	r11,r11,r9
	lxv	32+v0,0(r4)
	sldi	r6,r9,56
	stxvl   32+v0,r11,r6
	sub	r5,r5,r9

L(bwd_loop_head):
	srdi.	r7,r5,7
	beq	L(bwd_loop_tail)

	mtctr	r7

/* Main loop that copies 128 bytes every iteration.  */
	.p2align 5
L(bwd_loop):
	addi	r9,r4,-64
	addi	r10,r11,-64

	lxv	32+v0,-16(r4)
	lxv	32+v1,-32(r4)
	lxv	32+v2,-48(r4)
	lxv	32+v3,-64(r4)

	stxv	32+v0,-16(r11)
	stxv	32+v1,-32(r11)
	stxv	32+v2,-48(r11)
	stxv	32+v3,-64(r11)

	addi	r4,r4,-128
	addi	r11,r11,-128

	lxv	32+v0,-16(r9)
	lxv	32+v1,-32(r9)
	lxv	32+v2,-48(r9)
	lxv	32+v3,-64(r9)

	stxv	32+v0,-16(r10)
	stxv	32+v1,-32(r10)
	stxv	32+v2,-48(r10)
	stxv	32+v3,-64(r10)

	bdnz	L(bwd_loop)
	clrldi.	r5,r5,57
	beqlr

/* Copy 64 bytes.  */
	.p2align 5
L(bwd_loop_tail):
	cmpldi 	cr5,r5,63
	ble	cr5,L(bwd_final_64)

	addi	r4,r4,-64
	addi	r11,r11,-64

	lxv	32+v0,0(r4)
	lxv	32+v1,16(r4)
	lxv	32+v2,32(r4)
	lxv	32+v3,48(r4)

	stxv	32+v0,0(r11)
	stxv	32+v1,16(r11)
	stxv	32+v2,32(r11)
	stxv	32+v3,48(r11)

	subi	r5,r5,64

/* Copies the last 1-63 bytes.  */
	.p2align 5
L(bwd_final_64):
	/* r8 holds the number of bytes that will be copied with lxv/stxv.  */
	clrrdi.	r8,r5,4
	beq	L(tail1_bwd)

	cmpldi	cr5,r5,32
	lxv	32+v2,-16(r4)
	blt	cr5,L(tail2_bwd)

	cmpldi	cr6,r5,48
	lxv	32+v1,-32(r4)
	blt	cr6,L(tail3_bwd)

	.p2align 5
	lxv	32+v0,-48(r4)
	stxv	32+v0,-48(r11)
L(tail3_bwd):
	stxv	32+v1,-32(r11)
L(tail2_bwd):
	stxv	32+v2,-16(r11)
	sub	r4,r4,r5
	sub	r11,r11,r5
	sub	r5,r5,r8
	sldi	r6,r5,56
	lxvl	v4,r4,r6
	stxvl	v4,r11,r6
	blr

/* Copy last 16 bytes.  */
	.p2align 5
L(tail1_bwd):
	sub	r4,r4,r5
	sub	r11,r11,r5
	sldi	r6,r5,56
	lxvl	v4,r4,r6
	stxvl	v4,r11,r6
	blr

END_GEN_TB (MEMMOVE,TB_TOCLESS)
libc_hidden_builtin_def (memmove)