about summary refs log tree commit diff
path: root/sysdeps/powerpc/powerpc64/power8/memset.S
blob: 191a4df0a9ee305b45032d42d54ccd22143271f4 (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
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
/* Optimized memset implementation for PowerPC64/POWER8.
   Copyright (C) 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/>.  */

#include <sysdep.h>

/* __ptr_t [r3] memset (__ptr_t s [r3], int c [r4], size_t n [r5]));
   Returns 's'.  */

	.machine power8
EALIGN (memset, 5, 0)
	CALL_MCOUNT 3

L(_memset):
	cmpldi	cr7,r5,31
	neg	r0,r3
	mr	r10,r3

	insrdi	r4,r4,8,48
	insrdi	r4,r4,16,32	/* Replicate byte to word.  */
	ble	cr7,L(write_LT_32)

	andi.	r11,r10,15	/* Check alignment of DST.  */
	insrdi	r4,r4,32,0	/* Replicate word to double word.  */

	beq	L(big_aligned)

	mtocrf	0x01,r0
	clrldi	r0,r0,60

	/* Get DST aligned to 16 bytes.  */
1:	bf	31,2f
	stb	r4,0(r10)
	addi	r10,r10,1

2:	bf	30,4f
	sth	r4,0(r10)
	addi	r10,r10,2

4:	bf	29,8f
	stw	r4,0(r10)
	addi	r10,r10,4

8:	bf      28,16f
	std     r4,0(r10)
	addi    r10,r10,8

16:	subf	r5,r0,r5

	.align	4
L(big_aligned):
	/* For sizes larger than 255 two possible paths:
	   - if constant is '0', zero full cache lines with dcbz
	   - otherwise uses vector instructions.  */
	cmpldi	cr5,r5,255
	dcbtst	0,r10
	cmpldi	cr6,r4,0
	crand	27,26,21
	bt	27,L(huge_dcbz)
	bge	cr5,L(huge_vector)


	/* Size between 32 and 255 bytes with constant different than 0, use
	   doubleword store instruction to achieve best throughput.  */
	srdi    r8,r5,5
	clrldi  r11,r5,59
	cmpldi  cr6,r11,0
	cmpdi	r8,0
	beq     L(tail_bytes)
	mtctr   r8

	/* Main aligned write loop, writes 32-bytes at a time.  */
	.align  4
L(big_loop):
	std     r4,0(r10)
	std     r4,8(r10)
	std     r4,16(r10)
	std     r4,24(r10)
	addi    r10,r10,32
	bdz     L(tail_bytes)

	std     r4,0(r10)
	std     r4,8(r10)
	std     r4,16(r10)
	std     r4,24(r10)
	addi    r10,10,32
	bdnz    L(big_loop)

	b       L(tail_bytes)

	/* Write remaining 1~31 bytes.  */
	.align  4
L(tail_bytes):
	beqlr   cr6

	srdi    r7,r11,4
	clrldi  r8,r11,60
	mtocrf  0x01,r7

	.align	4
	bf	31,8f
	std	r4,0(r10)
	std	r4,8(r10)
	addi	r10,r10,16

	.align	4
8:	mtocrf	0x1,r8
	bf	28,4f
	std	r4,0(r10)
	addi	r10,r10,8

	.align	4
4:	bf      29,2f
	stw     4,0(10)
	addi    10,10,4

	.align 	4
2:	bf      30,1f
	sth     4,0(10)
	addi    10,10,2

	.align  4
1:      bflr    31
	stb     4,0(10)
	blr

	/* Size larger than 255 bytes with constant different than 0, use
	   vector instruction to achieve best throughput.  */
L(huge_vector):
	/* Replicate set byte to quadword in VMX register.  */
	mtvsrd	 v1,r4
	xxpermdi 32,v0,v1,0
	vspltb	 v2,v0,15

	/* Main aligned write loop: 128 bytes at a time.  */
	li	r6,16
	li	r7,32
	li	r8,48
	mtocrf	0x02,r5
	srdi	r12,r5,7
	cmpdi	r12,0
	beq	L(aligned_tail)
	mtctr	r12
	b	L(aligned_128loop)

	.align  4
L(aligned_128loop):
	stvx	v2,0,r10
	stvx	v2,r10,r6
	stvx	v2,r10,r7
	stvx	v2,r10,r8
	addi	r10,r10,64
	stvx	v2,0,r10
	stvx	v2,r10,r6
	stvx	v2,r10,r7
	stvx	v2,r10,r8
	addi	r10,r10,64
	bdnz	L(aligned_128loop)

	/* Write remaining 1~127 bytes.  */
L(aligned_tail):
	mtocrf	0x01,r5
	bf	25,32f
	stvx	v2,0,r10
	stvx	v2,r10,r6
	stvx	v2,r10,r7
	stvx	v2,r10,r8
	addi	r10,r10,64

32:	bf	26,16f
	stvx	v2,0,r10
	stvx	v2,r10,r6
	addi	r10,r10,32

16:	bf	27,8f
	stvx	v2,0,r10
	addi	r10,r10,16

8:	bf	28,4f
	std     r4,0(r10)
	addi	r10,r10,8

	/* Copies 4~7 bytes.  */
4:	bf	29,L(tail2)
	stw     r4,0(r10)
	bf      30,L(tail5)
	sth     r4,4(r10)
	bflr	31
	stb     r4,6(r10)
	/* Return original DST pointer.  */
	blr

	/* Special case when value is 0 and we have a long length to deal
	   with.  Use dcbz to zero out a full cacheline of 128 bytes at a time.
	   Before using dcbz though, we need to get the destination 128-byte
	   aligned.  */
	.align	4
L(huge_dcbz):
	andi.	r11,r10,127
	neg	r0,r10
	beq	L(huge_dcbz_aligned)

	clrldi	r0,r0,57
	subf	r5,r0,r5
	srdi	r0,r0,3
	mtocrf	0x01,r0

	/* Write 1~128 bytes until DST is aligned to 128 bytes.  */
8:	bf	28,4f

	std	r4,0(r10)
	std	r4,8(r10)
	std	r4,16(r10)
	std	r4,24(r10)
	std	r4,32(r10)
	std	r4,40(r10)
	std	r4,48(r10)
	std	r4,56(r10)
	addi	r10,r10,64

	.align	4
4:	bf	29,2f
	std	r4,0(r10)
	std	r4,8(r10)
	std	r4,16(r10)
	std	r4,24(r10)
	addi	r10,r10,32

	.align	4
2:	bf	30,1f
	std	r4,0(r10)
	std	r4,8(r10)
	addi	r10,r10,16

	.align	4
1:	bf	31,L(huge_dcbz_aligned)
	std	r4,0(r10)
	addi	r10,r10,8

L(huge_dcbz_aligned):
	/* Setup dcbz unroll offsets and count numbers.  */
	srdi	r8,r5,9
	clrldi	r11,r5,55
	cmpldi	cr6,r11,0
	li	r9,128
	cmpdi	r8,0
	beq     L(huge_tail)
	li	r7,256
	li	r6,384
	mtctr	r8

	.align	4
L(huge_loop):
	/* Sets 512 bytes to zero in each iteration, the loop unrolling shows
	   a throughput boost for large sizes (2048 bytes or higher).  */
	dcbz	0,r10
	dcbz	r9,r10
	dcbz	r7,r10
	dcbz	r6,r10
	addi	r10,r10,512
	bdnz	L(huge_loop)

	beqlr	cr6

L(huge_tail):
	srdi    r6,r11,8
	srdi    r7,r11,4
	clrldi  r8,r11,4
	cmpldi  cr6,r8,0
	mtocrf  0x01,r6

	beq	cr6,L(tail)

	/* We have 1~511 bytes remaining.  */
	.align	4
32:	bf	31,16f
	dcbz	0,r10
	dcbz	r9,r10
	addi	r10,r10,256

	.align	4
16:	mtocrf  0x01,r7
	bf	28,8f
	dcbz	0,r10
	addi	r10,r10,128

	.align 	4
8:	bf	29,4f
	std	r4,0(r10)
	std	r4,8(r10)
	std	r4,16(r10)
	std	r4,24(r10)
	std	r4,32(r10)
	std	r4,40(r10)
	std	r4,48(r10)
	std	r4,56(r10)
	addi	r10,r10,64

	.align	4
4:	bf	30,2f
	std	r4,0(r10)
	std	r4,8(r10)
	std	r4,16(r10)
	std	r4,24(r10)
	addi	r10,r10,32

	.align	4
2:	bf	31,L(tail)
	std	r4,0(r10)
	std	r4,8(r10)
	addi	r10,r10,16
	.align	4

	/* Remaining 1~15 bytes.  */
L(tail):
	mtocrf  0x01,r8

	.align
8:	bf	28,4f
	std	r4,0(r10)
	addi	r10,r10,8

	.align	4
4:	bf	29,2f
	stw	r4,0(r10)
	addi	r10,r10,4

	.align	4
2:	bf	30,1f
	sth	r4,0(r10)
	addi	r10,r10,2

	.align	4
1:	bflr	31
	stb	r4,0(r10)
	blr

	/* Handle short copies of 0~31 bytes.  Best throughput is achieved
	   by just unrolling all operations.  */
	.align	4
L(write_LT_32):
	cmpldi	cr6,5,8
	mtocrf	0x01,r5
	ble	cr6,L(write_LE_8)

	/* At least 9 bytes to go.  */
	neg	r8,r4
	andi.	r0,r8,3
	cmpldi	cr1,r5,16
	beq	L(write_LT_32_aligned)

	/* Force 4-byte alignment for SRC.  */
	mtocrf	0x01,r0
	subf	r5,r0,r5

2:	bf	30,1f
	sth	r4,0(r10)
	addi	r10,r10,2

1:	bf	31,L(end_4bytes_alignment)
	stb	r4,0(r10)
	addi	r10,r10,1

	.align	4
L(end_4bytes_alignment):
	cmpldi	cr1,r5,16
	mtocrf	0x01,r5

L(write_LT_32_aligned):
	blt	cr1,8f

	stw	r4,0(r10)
	stw	r4,4(r10)
	stw	r4,8(r10)
	stw	r4,12(r10)
	addi	r10,r10,16

8:	bf	28,L(tail4)
	stw	r4,0(r10)
	stw	r4,4(r10)
	addi	r10,r10,8

	.align	4
	/* Copies 4~7 bytes.  */
L(tail4):
	bf	29,L(tail2)
	stw	r4,0(r10)
	bf	30,L(tail5)
	sth	r4,4(r10)
	bflr	31
	stb	r4,6(r10)
	blr

	.align	4
	/* Copies 2~3 bytes.  */
L(tail2):
	bf	30,1f
	sth	r4,0(r10)
	bflr	31
	stb	r4,2(r10)
	blr

	.align	4
L(tail5):
	bflr	31
	stb	r4,4(r10)
	blr

	.align	4
1: 	bflr	31
	stb	r4,0(r10)
	blr

	/* Handles copies of 0~8 bytes.  */
	.align	4
L(write_LE_8):
	bne	cr6,L(tail4)

	stw	r4,0(r10)
	stw	r4,4(r10)
	blr
END_GEN_TB (memset,TB_TOCLESS)
libc_hidden_builtin_def (memset)

/* Copied from bzero.S to prevent the linker from inserting a stub
   between bzero and memset.  */
ENTRY (__bzero)
	CALL_MCOUNT 3
	mr	r5,r4
	li	r4,0
	b	L(_memset)
END (__bzero)
#ifndef __bzero
weak_alias (__bzero, bzero)
#endif