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
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
|
// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build !math_big_pure_go,s390x
#include "textflag.h"
// This file provides fast assembly versions for the elementary
// arithmetic operations on vectors implemented in arith.go.
TEXT ·mulWW(SB), NOSPLIT, $0
MOVD x+0(FP), R3
MOVD y+8(FP), R4
MULHDU R3, R4
MOVD R10, z1+16(FP)
MOVD R11, z0+24(FP)
RET
// DI = R3, CX = R4, SI = r10, r8 = r8, r9=r9, r10 = r2 , r11 = r5, r12 = r6, r13 = r7, r14 = r1 (R0 set to 0) + use R11
// func addVV(z, x, y []Word) (c Word)
TEXT ·addVV(SB), NOSPLIT, $0
MOVD addvectorfacility+0x00(SB), R1
BR (R1)
TEXT ·addVV_check(SB), NOSPLIT, $0
MOVB ·hasVX(SB), R1
CMPBEQ R1, $1, vectorimpl // vectorfacility = 1, vector supported
MOVD $addvectorfacility+0x00(SB), R1
MOVD $·addVV_novec(SB), R2
MOVD R2, 0(R1)
// MOVD $·addVV_novec(SB), 0(R1)
BR ·addVV_novec(SB)
vectorimpl:
MOVD $addvectorfacility+0x00(SB), R1
MOVD $·addVV_vec(SB), R2
MOVD R2, 0(R1)
// MOVD $·addVV_vec(SB), 0(R1)
BR ·addVV_vec(SB)
GLOBL addvectorfacility+0x00(SB), NOPTR, $8
DATA addvectorfacility+0x00(SB)/8, $·addVV_check(SB)
TEXT ·addVV_vec(SB), NOSPLIT, $0
MOVD z_len+8(FP), R3
MOVD x+24(FP), R8
MOVD y+48(FP), R9
MOVD z+0(FP), R2
MOVD $0, R4 // c = 0
MOVD $0, R0 // make sure it's zero
MOVD $0, R10 // i = 0
// s/JL/JMP/ below to disable the unrolled loop
SUB $4, R3
BLT v1
SUB $12, R3 // n -= 16
BLT A1 // if n < 0 goto A1
MOVD R8, R5
MOVD R9, R6
MOVD R2, R7
// n >= 0
// regular loop body unrolled 16x
VZERO V0 // c = 0
UU1:
VLM 0(R5), V1, V4 // 64-bytes into V1..V8
ADD $64, R5
VPDI $0x4, V1, V1, V1 // flip the doublewords to big-endian order
VPDI $0x4, V2, V2, V2 // flip the doublewords to big-endian order
VLM 0(R6), V9, V12 // 64-bytes into V9..V16
ADD $64, R6
VPDI $0x4, V9, V9, V9 // flip the doublewords to big-endian order
VPDI $0x4, V10, V10, V10 // flip the doublewords to big-endian order
VACCCQ V1, V9, V0, V25
VACQ V1, V9, V0, V17
VACCCQ V2, V10, V25, V26
VACQ V2, V10, V25, V18
VLM 0(R5), V5, V6 // 32-bytes into V1..V8
VLM 0(R6), V13, V14 // 32-bytes into V9..V16
ADD $32, R5
ADD $32, R6
VPDI $0x4, V3, V3, V3 // flip the doublewords to big-endian order
VPDI $0x4, V4, V4, V4 // flip the doublewords to big-endian order
VPDI $0x4, V11, V11, V11 // flip the doublewords to big-endian order
VPDI $0x4, V12, V12, V12 // flip the doublewords to big-endian order
VACCCQ V3, V11, V26, V27
VACQ V3, V11, V26, V19
VACCCQ V4, V12, V27, V28
VACQ V4, V12, V27, V20
VLM 0(R5), V7, V8 // 32-bytes into V1..V8
VLM 0(R6), V15, V16 // 32-bytes into V9..V16
ADD $32, R5
ADD $32, R6
VPDI $0x4, V5, V5, V5 // flip the doublewords to big-endian order
VPDI $0x4, V6, V6, V6 // flip the doublewords to big-endian order
VPDI $0x4, V13, V13, V13 // flip the doublewords to big-endian order
VPDI $0x4, V14, V14, V14 // flip the doublewords to big-endian order
VACCCQ V5, V13, V28, V29
VACQ V5, V13, V28, V21
VACCCQ V6, V14, V29, V30
VACQ V6, V14, V29, V22
VPDI $0x4, V7, V7, V7 // flip the doublewords to big-endian order
VPDI $0x4, V8, V8, V8 // flip the doublewords to big-endian order
VPDI $0x4, V15, V15, V15 // flip the doublewords to big-endian order
VPDI $0x4, V16, V16, V16 // flip the doublewords to big-endian order
VACCCQ V7, V15, V30, V31
VACQ V7, V15, V30, V23
VACCCQ V8, V16, V31, V0 // V0 has carry-over
VACQ V8, V16, V31, V24
VPDI $0x4, V17, V17, V17 // flip the doublewords to big-endian order
VPDI $0x4, V18, V18, V18 // flip the doublewords to big-endian order
VPDI $0x4, V19, V19, V19 // flip the doublewords to big-endian order
VPDI $0x4, V20, V20, V20 // flip the doublewords to big-endian order
VPDI $0x4, V21, V21, V21 // flip the doublewords to big-endian order
VPDI $0x4, V22, V22, V22 // flip the doublewords to big-endian order
VPDI $0x4, V23, V23, V23 // flip the doublewords to big-endian order
VPDI $0x4, V24, V24, V24 // flip the doublewords to big-endian order
VSTM V17, V24, 0(R7) // 128-bytes into z
ADD $128, R7
ADD $128, R10 // i += 16
SUB $16, R3 // n -= 16
BGE UU1 // if n >= 0 goto U1
VLGVG $1, V0, R4 // put cf into R4
NEG R4, R4 // save cf
A1:
ADD $12, R3 // n += 16
// s/JL/JMP/ below to disable the unrolled loop
BLT v1 // if n < 0 goto v1
U1: // n >= 0
// regular loop body unrolled 4x
MOVD 0(R8)(R10*1), R5
MOVD 8(R8)(R10*1), R6
MOVD 16(R8)(R10*1), R7
MOVD 24(R8)(R10*1), R1
ADDC R4, R4 // restore CF
MOVD 0(R9)(R10*1), R11
ADDE R11, R5
MOVD 8(R9)(R10*1), R11
ADDE R11, R6
MOVD 16(R9)(R10*1), R11
ADDE R11, R7
MOVD 24(R9)(R10*1), R11
ADDE R11, R1
MOVD R0, R4
ADDE R4, R4 // save CF
NEG R4, R4
MOVD R5, 0(R2)(R10*1)
MOVD R6, 8(R2)(R10*1)
MOVD R7, 16(R2)(R10*1)
MOVD R1, 24(R2)(R10*1)
ADD $32, R10 // i += 4
SUB $4, R3 // n -= 4
BGE U1 // if n >= 0 goto U1
v1:
ADD $4, R3 // n += 4
BLE E1 // if n <= 0 goto E1
L1: // n > 0
ADDC R4, R4 // restore CF
MOVD 0(R8)(R10*1), R5
MOVD 0(R9)(R10*1), R11
ADDE R11, R5
MOVD R5, 0(R2)(R10*1)
MOVD R0, R4
ADDE R4, R4 // save CF
NEG R4, R4
ADD $8, R10 // i++
SUB $1, R3 // n--
BGT L1 // if n > 0 goto L1
E1:
NEG R4, R4
MOVD R4, c+72(FP) // return c
RET
TEXT ·addVV_novec(SB), NOSPLIT, $0
novec:
MOVD z_len+8(FP), R3
MOVD x+24(FP), R8
MOVD y+48(FP), R9
MOVD z+0(FP), R2
MOVD $0, R4 // c = 0
MOVD $0, R0 // make sure it's zero
MOVD $0, R10 // i = 0
// s/JL/JMP/ below to disable the unrolled loop
SUB $4, R3 // n -= 4
BLT v1n // if n < 0 goto v1n
U1n: // n >= 0
// regular loop body unrolled 4x
MOVD 0(R8)(R10*1), R5
MOVD 8(R8)(R10*1), R6
MOVD 16(R8)(R10*1), R7
MOVD 24(R8)(R10*1), R1
ADDC R4, R4 // restore CF
MOVD 0(R9)(R10*1), R11
ADDE R11, R5
MOVD 8(R9)(R10*1), R11
ADDE R11, R6
MOVD 16(R9)(R10*1), R11
ADDE R11, R7
MOVD 24(R9)(R10*1), R11
ADDE R11, R1
MOVD R0, R4
ADDE R4, R4 // save CF
NEG R4, R4
MOVD R5, 0(R2)(R10*1)
MOVD R6, 8(R2)(R10*1)
MOVD R7, 16(R2)(R10*1)
MOVD R1, 24(R2)(R10*1)
ADD $32, R10 // i += 4
SUB $4, R3 // n -= 4
BGE U1n // if n >= 0 goto U1n
v1n:
ADD $4, R3 // n += 4
BLE E1n // if n <= 0 goto E1n
L1n: // n > 0
ADDC R4, R4 // restore CF
MOVD 0(R8)(R10*1), R5
MOVD 0(R9)(R10*1), R11
ADDE R11, R5
MOVD R5, 0(R2)(R10*1)
MOVD R0, R4
ADDE R4, R4 // save CF
NEG R4, R4
ADD $8, R10 // i++
SUB $1, R3 // n--
BGT L1n // if n > 0 goto L1n
E1n:
NEG R4, R4
MOVD R4, c+72(FP) // return c
RET
TEXT ·subVV(SB), NOSPLIT, $0
MOVD subvectorfacility+0x00(SB), R1
BR (R1)
TEXT ·subVV_check(SB), NOSPLIT, $0
MOVB ·hasVX(SB), R1
CMPBEQ R1, $1, vectorimpl // vectorfacility = 1, vector supported
MOVD $subvectorfacility+0x00(SB), R1
MOVD $·subVV_novec(SB), R2
MOVD R2, 0(R1)
// MOVD $·subVV_novec(SB), 0(R1)
BR ·subVV_novec(SB)
vectorimpl:
MOVD $subvectorfacility+0x00(SB), R1
MOVD $·subVV_vec(SB), R2
MOVD R2, 0(R1)
// MOVD $·subVV_vec(SB), 0(R1)
BR ·subVV_vec(SB)
GLOBL subvectorfacility+0x00(SB), NOPTR, $8
DATA subvectorfacility+0x00(SB)/8, $·subVV_check(SB)
// DI = R3, CX = R4, SI = r10, r8 = r8, r9=r9, r10 = r2 , r11 = r5, r12 = r6, r13 = r7, r14 = r1 (R0 set to 0) + use R11
// func subVV(z, x, y []Word) (c Word)
// (same as addVV except for SUBC/SUBE instead of ADDC/ADDE and label names)
TEXT ·subVV_vec(SB), NOSPLIT, $0
MOVD z_len+8(FP), R3
MOVD x+24(FP), R8
MOVD y+48(FP), R9
MOVD z+0(FP), R2
MOVD $0, R4 // c = 0
MOVD $0, R0 // make sure it's zero
MOVD $0, R10 // i = 0
// s/JL/JMP/ below to disable the unrolled loop
SUB $4, R3 // n -= 4
BLT v1 // if n < 0 goto v1
SUB $12, R3 // n -= 16
BLT A1 // if n < 0 goto A1
MOVD R8, R5
MOVD R9, R6
MOVD R2, R7
// n >= 0
// regular loop body unrolled 16x
VZERO V0 // cf = 0
MOVD $1, R4 // for 390 subtraction cf starts as 1 (no borrow)
VLVGG $1, R4, V0 // put carry into V0
UU1:
VLM 0(R5), V1, V4 // 64-bytes into V1..V8
ADD $64, R5
VPDI $0x4, V1, V1, V1 // flip the doublewords to big-endian order
VPDI $0x4, V2, V2, V2 // flip the doublewords to big-endian order
VLM 0(R6), V9, V12 // 64-bytes into V9..V16
ADD $64, R6
VPDI $0x4, V9, V9, V9 // flip the doublewords to big-endian order
VPDI $0x4, V10, V10, V10 // flip the doublewords to big-endian order
VSBCBIQ V1, V9, V0, V25
VSBIQ V1, V9, V0, V17
VSBCBIQ V2, V10, V25, V26
VSBIQ V2, V10, V25, V18
VLM 0(R5), V5, V6 // 32-bytes into V1..V8
VLM 0(R6), V13, V14 // 32-bytes into V9..V16
ADD $32, R5
ADD $32, R6
VPDI $0x4, V3, V3, V3 // flip the doublewords to big-endian order
VPDI $0x4, V4, V4, V4 // flip the doublewords to big-endian order
VPDI $0x4, V11, V11, V11 // flip the doublewords to big-endian order
VPDI $0x4, V12, V12, V12 // flip the doublewords to big-endian order
VSBCBIQ V3, V11, V26, V27
VSBIQ V3, V11, V26, V19
VSBCBIQ V4, V12, V27, V28
VSBIQ V4, V12, V27, V20
VLM 0(R5), V7, V8 // 32-bytes into V1..V8
VLM 0(R6), V15, V16 // 32-bytes into V9..V16
ADD $32, R5
ADD $32, R6
VPDI $0x4, V5, V5, V5 // flip the doublewords to big-endian order
VPDI $0x4, V6, V6, V6 // flip the doublewords to big-endian order
VPDI $0x4, V13, V13, V13 // flip the doublewords to big-endian order
VPDI $0x4, V14, V14, V14 // flip the doublewords to big-endian order
VSBCBIQ V5, V13, V28, V29
VSBIQ V5, V13, V28, V21
VSBCBIQ V6, V14, V29, V30
VSBIQ V6, V14, V29, V22
VPDI $0x4, V7, V7, V7 // flip the doublewords to big-endian order
VPDI $0x4, V8, V8, V8 // flip the doublewords to big-endian order
VPDI $0x4, V15, V15, V15 // flip the doublewords to big-endian order
VPDI $0x4, V16, V16, V16 // flip the doublewords to big-endian order
VSBCBIQ V7, V15, V30, V31
VSBIQ V7, V15, V30, V23
VSBCBIQ V8, V16, V31, V0 // V0 has carry-over
VSBIQ V8, V16, V31, V24
VPDI $0x4, V17, V17, V17 // flip the doublewords to big-endian order
VPDI $0x4, V18, V18, V18 // flip the doublewords to big-endian order
VPDI $0x4, V19, V19, V19 // flip the doublewords to big-endian order
VPDI $0x4, V20, V20, V20 // flip the doublewords to big-endian order
VPDI $0x4, V21, V21, V21 // flip the doublewords to big-endian order
VPDI $0x4, V22, V22, V22 // flip the doublewords to big-endian order
VPDI $0x4, V23, V23, V23 // flip the doublewords to big-endian order
VPDI $0x4, V24, V24, V24 // flip the doublewords to big-endian order
VSTM V17, V24, 0(R7) // 128-bytes into z
ADD $128, R7
ADD $128, R10 // i += 16
SUB $16, R3 // n -= 16
BGE UU1 // if n >= 0 goto U1
VLGVG $1, V0, R4 // put cf into R4
SUB $1, R4 // save cf
A1:
ADD $12, R3 // n += 16
BLT v1 // if n < 0 goto v1
U1: // n >= 0
// regular loop body unrolled 4x
MOVD 0(R8)(R10*1), R5
MOVD 8(R8)(R10*1), R6
MOVD 16(R8)(R10*1), R7
MOVD 24(R8)(R10*1), R1
MOVD R0, R11
SUBC R4, R11 // restore CF
MOVD 0(R9)(R10*1), R11
SUBE R11, R5
MOVD 8(R9)(R10*1), R11
SUBE R11, R6
MOVD 16(R9)(R10*1), R11
SUBE R11, R7
MOVD 24(R9)(R10*1), R11
SUBE R11, R1
MOVD R0, R4
SUBE R4, R4 // save CF
MOVD R5, 0(R2)(R10*1)
MOVD R6, 8(R2)(R10*1)
MOVD R7, 16(R2)(R10*1)
MOVD R1, 24(R2)(R10*1)
ADD $32, R10 // i += 4
SUB $4, R3 // n -= 4
BGE U1 // if n >= 0 goto U1n
v1:
ADD $4, R3 // n += 4
BLE E1 // if n <= 0 goto E1
L1: // n > 0
MOVD R0, R11
SUBC R4, R11 // restore CF
MOVD 0(R8)(R10*1), R5
MOVD 0(R9)(R10*1), R11
SUBE R11, R5
MOVD R5, 0(R2)(R10*1)
MOVD R0, R4
SUBE R4, R4 // save CF
ADD $8, R10 // i++
SUB $1, R3 // n--
BGT L1 // if n > 0 goto L1n
E1:
NEG R4, R4
MOVD R4, c+72(FP) // return c
RET
// DI = R3, CX = R4, SI = r10, r8 = r8, r9=r9, r10 = r2 , r11 = r5, r12 = r6, r13 = r7, r14 = r1 (R0 set to 0) + use R11
// func subVV(z, x, y []Word) (c Word)
// (same as addVV except for SUBC/SUBE instead of ADDC/ADDE and label names)
TEXT ·subVV_novec(SB), NOSPLIT, $0
MOVD z_len+8(FP), R3
MOVD x+24(FP), R8
MOVD y+48(FP), R9
MOVD z+0(FP), R2
MOVD $0, R4 // c = 0
MOVD $0, R0 // make sure it's zero
MOVD $0, R10 // i = 0
// s/JL/JMP/ below to disable the unrolled loop
SUB $4, R3 // n -= 4
BLT v1 // if n < 0 goto v1
U1: // n >= 0
// regular loop body unrolled 4x
MOVD 0(R8)(R10*1), R5
MOVD 8(R8)(R10*1), R6
MOVD 16(R8)(R10*1), R7
MOVD 24(R8)(R10*1), R1
MOVD R0, R11
SUBC R4, R11 // restore CF
MOVD 0(R9)(R10*1), R11
SUBE R11, R5
MOVD 8(R9)(R10*1), R11
SUBE R11, R6
MOVD 16(R9)(R10*1), R11
SUBE R11, R7
MOVD 24(R9)(R10*1), R11
SUBE R11, R1
MOVD R0, R4
SUBE R4, R4 // save CF
MOVD R5, 0(R2)(R10*1)
MOVD R6, 8(R2)(R10*1)
MOVD R7, 16(R2)(R10*1)
MOVD R1, 24(R2)(R10*1)
ADD $32, R10 // i += 4
SUB $4, R3 // n -= 4
BGE U1 // if n >= 0 goto U1
v1:
ADD $4, R3 // n += 4
BLE E1 // if n <= 0 goto E1
L1: // n > 0
MOVD R0, R11
SUBC R4, R11 // restore CF
MOVD 0(R8)(R10*1), R5
MOVD 0(R9)(R10*1), R11
SUBE R11, R5
MOVD R5, 0(R2)(R10*1)
MOVD R0, R4
SUBE R4, R4 // save CF
ADD $8, R10 // i++
SUB $1, R3 // n--
BGT L1 // if n > 0 goto L1
E1:
NEG R4, R4
MOVD R4, c+72(FP) // return c
RET
TEXT ·addVW(SB), NOSPLIT, $0
MOVD z_len+8(FP), R5 // length of z
MOVD x+24(FP), R6
MOVD y+48(FP), R7 // c = y
MOVD z+0(FP), R8
CMPBEQ R5, $0, returnC // if len(z) == 0, we can have an early return
// Add the first two words, and determine which path (copy path or loop path) to take based on the carry flag.
ADDC 0(R6), R7
MOVD R7, 0(R8)
CMPBEQ R5, $1, returnResult // len(z) == 1
MOVD $0, R9
ADDE 8(R6), R9
MOVD R9, 8(R8)
CMPBEQ R5, $2, returnResult // len(z) == 2
// Update the counters
MOVD $16, R12 // i = 2
MOVD $-2(R5), R5 // n = n - 2
loopOverEachWord:
BRC $12, copySetup // carry = 0, copy the rest
MOVD $1, R9
// Originally we used the carry flag generated in the previous iteration
// (i.e: ADDE could be used here to do the addition). However, since we
// already know carry is 1 (otherwise we will go to copy section), we can use
// ADDC here so the current iteration does not depend on the carry flag
// generated in the previous iteration. This could be useful when branch prediction happens.
ADDC 0(R6)(R12*1), R9
MOVD R9, 0(R8)(R12*1) // z[i] = x[i] + c
MOVD $8(R12), R12 // i++
BRCTG R5, loopOverEachWord // n--
// Return the current carry value
returnResult:
MOVD $0, R0
ADDE R0, R0
MOVD R0, c+56(FP)
RET
// Update position of x(R6) and z(R8) based on the current counter value and perform copying.
// With the assumption that x and z will not overlap with each other or x and z will
// point to same memory region, we can use a faster version of copy using only MVC here.
// In the following implementation, we have three copy loops, each copying a word, 4 words, and
// 32 words at a time. Via benchmarking, this implementation is faster than calling runtime·memmove.
copySetup:
ADD R12, R6
ADD R12, R8
CMPBGE R5, $4, mediumLoop
smallLoop: // does a loop unrolling to copy word when n < 4
CMPBEQ R5, $0, returnZero
MVC $8, 0(R6), 0(R8)
CMPBEQ R5, $1, returnZero
MVC $8, 8(R6), 8(R8)
CMPBEQ R5, $2, returnZero
MVC $8, 16(R6), 16(R8)
returnZero:
MOVD $0, c+56(FP) // return 0 as carry
RET
mediumLoop:
CMPBLT R5, $4, smallLoop
CMPBLT R5, $32, mediumLoopBody
largeLoop: // Copying 256 bytes at a time.
MVC $256, 0(R6), 0(R8)
MOVD $256(R6), R6
MOVD $256(R8), R8
MOVD $-32(R5), R5
CMPBGE R5, $32, largeLoop
BR mediumLoop
mediumLoopBody: // Copying 32 bytes at a time
MVC $32, 0(R6), 0(R8)
MOVD $32(R6), R6
MOVD $32(R8), R8
MOVD $-4(R5), R5
CMPBGE R5, $4, mediumLoopBody
BR smallLoop
returnC:
MOVD R7, c+56(FP)
RET
TEXT ·subVW(SB), NOSPLIT, $0
MOVD z_len+8(FP), R5
MOVD x+24(FP), R6
MOVD y+48(FP), R7 // The borrow bit passed in
MOVD z+0(FP), R8
MOVD $0, R0 // R0 is a temporary variable used during computation. Ensure it has zero in it.
CMPBEQ R5, $0, returnC // len(z) == 0, have an early return
// Subtract the first two words, and determine which path (copy path or loop path) to take based on the borrow flag
MOVD 0(R6), R9
SUBC R7, R9
MOVD R9, 0(R8)
CMPBEQ R5, $1, returnResult
MOVD 8(R6), R9
SUBE R0, R9
MOVD R9, 8(R8)
CMPBEQ R5, $2, returnResult
// Update the counters
MOVD $16, R12 // i = 2
MOVD $-2(R5), R5 // n = n - 2
loopOverEachWord:
BRC $3, copySetup // no borrow, copy the rest
MOVD 0(R6)(R12*1), R9
// Originally we used the borrow flag generated in the previous iteration
// (i.e: SUBE could be used here to do the subtraction). However, since we
// already know borrow is 1 (otherwise we will go to copy section), we can
// use SUBC here so the current iteration does not depend on the borrow flag
// generated in the previous iteration. This could be useful when branch prediction happens.
SUBC $1, R9
MOVD R9, 0(R8)(R12*1) // z[i] = x[i] - 1
MOVD $8(R12), R12 // i++
BRCTG R5, loopOverEachWord // n--
// return the current borrow value
returnResult:
SUBE R0, R0
NEG R0, R0
MOVD R0, c+56(FP)
RET
// Update position of x(R6) and z(R8) based on the current counter value and perform copying.
// With the assumption that x and z will not overlap with each other or x and z will
// point to same memory region, we can use a faster version of copy using only MVC here.
// In the following implementation, we have three copy loops, each copying a word, 4 words, and
// 32 words at a time. Via benchmarking, this implementation is faster than calling runtime·memmove.
copySetup:
ADD R12, R6
ADD R12, R8
CMPBGE R5, $4, mediumLoop
smallLoop: // does a loop unrolling to copy word when n < 4
CMPBEQ R5, $0, returnZero
MVC $8, 0(R6), 0(R8)
CMPBEQ R5, $1, returnZero
MVC $8, 8(R6), 8(R8)
CMPBEQ R5, $2, returnZero
MVC $8, 16(R6), 16(R8)
returnZero:
MOVD $0, c+56(FP) // return 0 as borrow
RET
mediumLoop:
CMPBLT R5, $4, smallLoop
CMPBLT R5, $32, mediumLoopBody
largeLoop: // Copying 256 bytes at a time
MVC $256, 0(R6), 0(R8)
MOVD $256(R6), R6
MOVD $256(R8), R8
MOVD $-32(R5), R5
CMPBGE R5, $32, largeLoop
BR mediumLoop
mediumLoopBody: // Copying 32 bytes at a time
MVC $32, 0(R6), 0(R8)
MOVD $32(R6), R6
MOVD $32(R8), R8
MOVD $-4(R5), R5
CMPBGE R5, $4, mediumLoopBody
BR smallLoop
returnC:
MOVD R7, c+56(FP)
RET
// func shlVU(z, x []Word, s uint) (c Word)
TEXT ·shlVU(SB), NOSPLIT, $0
BR ·shlVU_g(SB)
// func shrVU(z, x []Word, s uint) (c Word)
TEXT ·shrVU(SB), NOSPLIT, $0
BR ·shrVU_g(SB)
// CX = R4, r8 = r8, r9=r9, r10 = r2 , r11 = r5, DX = r3, AX = r6 , BX = R1 , (R0 set to 0) + use R11 + use R7 for i
// func mulAddVWW(z, x []Word, y, r Word) (c Word)
TEXT ·mulAddVWW(SB), NOSPLIT, $0
MOVD z+0(FP), R2
MOVD x+24(FP), R8
MOVD y+48(FP), R9
MOVD r+56(FP), R4 // c = r
MOVD z_len+8(FP), R5
MOVD $0, R1 // i = 0
MOVD $0, R7 // i*8 = 0
MOVD $0, R0 // make sure it's zero
BR E5
L5:
MOVD (R8)(R1*1), R6
MULHDU R9, R6
ADDC R4, R11 // add to low order bits
ADDE R0, R6
MOVD R11, (R2)(R1*1)
MOVD R6, R4
ADD $8, R1 // i*8 + 8
ADD $1, R7 // i++
E5:
CMPBLT R7, R5, L5 // i < n
MOVD R4, c+64(FP)
RET
// func addMulVVW(z, x []Word, y Word) (c Word)
// CX = R4, r8 = r8, r9=r9, r10 = r2 , r11 = r5, AX = r11, DX = R6, r12=r12, BX = R1 , (R0 set to 0) + use R11 + use R7 for i
TEXT ·addMulVVW(SB), NOSPLIT, $0
MOVD z+0(FP), R2
MOVD x+24(FP), R8
MOVD y+48(FP), R9
MOVD z_len+8(FP), R5
MOVD $0, R1 // i*8 = 0
MOVD $0, R7 // i = 0
MOVD $0, R0 // make sure it's zero
MOVD $0, R4 // c = 0
MOVD R5, R12
AND $-2, R12
CMPBGE R5, $2, A6
BR E6
A6:
MOVD (R8)(R1*1), R6
MULHDU R9, R6
MOVD (R2)(R1*1), R10
ADDC R10, R11 // add to low order bits
ADDE R0, R6
ADDC R4, R11
ADDE R0, R6
MOVD R6, R4
MOVD R11, (R2)(R1*1)
MOVD (8)(R8)(R1*1), R6
MULHDU R9, R6
MOVD (8)(R2)(R1*1), R10
ADDC R10, R11 // add to low order bits
ADDE R0, R6
ADDC R4, R11
ADDE R0, R6
MOVD R6, R4
MOVD R11, (8)(R2)(R1*1)
ADD $16, R1 // i*8 + 8
ADD $2, R7 // i++
CMPBLT R7, R12, A6
BR E6
L6:
MOVD (R8)(R1*1), R6
MULHDU R9, R6
MOVD (R2)(R1*1), R10
ADDC R10, R11 // add to low order bits
ADDE R0, R6
ADDC R4, R11
ADDE R0, R6
MOVD R6, R4
MOVD R11, (R2)(R1*1)
ADD $8, R1 // i*8 + 8
ADD $1, R7 // i++
E6:
CMPBLT R7, R5, L6 // i < n
MOVD R4, c+56(FP)
RET
|
