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
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
|
/* Optimized memcmp implementation for POWER7/PowerPC64.
Copyright (C) 2010-2016 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>
/* int [r3] memcmp (const char *s1 [r3],
const char *s2 [r4],
size_t size [r5]) */
.machine power7
EALIGN (memcmp, 4, 0)
CALL_MCOUNT 3
#define rRTN r3
#define rSTR1 r3 /* first string arg */
#define rSTR2 r4 /* second string arg */
#define rN r5 /* max string length */
#define rWORD1 r6 /* current word in s1 */
#define rWORD2 r7 /* current word in s2 */
#define rWORD3 r8 /* next word in s1 */
#define rWORD4 r9 /* next word in s2 */
#define rWORD5 r10 /* next word in s1 */
#define rWORD6 r11 /* next word in s2 */
#define rOFF8 r20 /* 8 bytes offset. */
#define rOFF16 r21 /* 16 bytes offset. */
#define rOFF24 r22 /* 24 bytes offset. */
#define rOFF32 r23 /* 24 bytes offset. */
#define rWORD6_SHIFT r24 /* Left rotation temp for rWORD8. */
#define rWORD4_SHIFT r25 /* Left rotation temp for rWORD6. */
#define rWORD2_SHIFT r26 /* Left rotation temp for rWORD4. */
#define rWORD8_SHIFT r27 /* Left rotation temp for rWORD2. */
#define rSHR r28 /* Unaligned shift right count. */
#define rSHL r29 /* Unaligned shift left count. */
#define rWORD7 r30 /* next word in s1 */
#define rWORD8 r31 /* next word in s2 */
#define rWORD8SAVE (-8)
#define rWORD7SAVE (-16)
#define rOFF8SAVE (-24)
#define rOFF16SAVE (-32)
#define rOFF24SAVE (-40)
#define rOFF32SAVE (-48)
#define rSHRSAVE (-56)
#define rSHLSAVE (-64)
#define rWORD8SHIFTSAVE (-72)
#define rWORD2SHIFTSAVE (-80)
#define rWORD4SHIFTSAVE (-88)
#define rWORD6SHIFTSAVE (-96)
#ifdef __LITTLE_ENDIAN__
# define LD ldbrx
#else
# define LD ldx
#endif
xor r0, rSTR2, rSTR1
cmpldi cr6, rN, 0
cmpldi cr1, rN, 12
clrldi. r0, r0, 61
clrldi r12, rSTR1, 61
cmpldi cr5, r12, 0
beq- cr6, L(zeroLength)
dcbt 0, rSTR1
dcbt 0, rSTR2
/* If less than 8 bytes or not aligned, use the unaligned
byte loop. */
blt cr1, L(bytealigned)
std rWORD8, rWORD8SAVE(r1)
cfi_offset(rWORD8, rWORD8SAVE)
std rWORD7, rWORD7SAVE(r1)
cfi_offset(rWORD7, rWORD7SAVE)
std rOFF8, rOFF8SAVE(r1)
cfi_offset(rWORD7, rOFF8SAVE)
std rOFF16, rOFF16SAVE(r1)
cfi_offset(rWORD7, rOFF16SAVE)
std rOFF24, rOFF24SAVE(r1)
cfi_offset(rWORD7, rOFF24SAVE)
std rOFF32, rOFF32SAVE(r1)
cfi_offset(rWORD7, rOFF32SAVE)
li rOFF8,8
li rOFF16,16
li rOFF24,24
li rOFF32,32
bne L(unaligned)
/* At this point we know both strings have the same alignment and the
compare length is at least 8 bytes. r12 contains the low order
3 bits of rSTR1 and cr5 contains the result of the logical compare
of r12 to 0. If r12 == 0 then we are already double word
aligned and can perform the DW aligned loop.
Otherwise we know the two strings have the same alignment (but not
yet DW). So we force the string addresses to the next lower DW
boundary and special case this first DW using shift left to
eliminate bits preceding the first byte. Since we want to join the
normal (DW aligned) compare loop, starting at the second double word,
we need to adjust the length (rN) and special case the loop
versioning for the first DW. This ensures that the loop count is
correct and the first DW (shifted) is in the expected register pair. */
.align 4
L(samealignment):
clrrdi rSTR1, rSTR1, 3
clrrdi rSTR2, rSTR2, 3
beq cr5, L(DWaligned)
add rN, rN, r12
sldi rWORD6, r12, 3
srdi r0, rN, 5 /* Divide by 32 */
andi. r12, rN, 24 /* Get the DW remainder */
LD rWORD1, 0, rSTR1
LD rWORD2, 0, rSTR2
cmpldi cr1, r12, 16
cmpldi cr7, rN, 32
clrldi rN, rN, 61
beq L(dPs4)
mtctr r0
bgt cr1, L(dPs3)
beq cr1, L(dPs2)
/* Remainder is 8 */
.align 3
L(dsP1):
sld rWORD5, rWORD1, rWORD6
sld rWORD6, rWORD2, rWORD6
cmpld cr5, rWORD5, rWORD6
blt cr7, L(dP1x)
/* Do something useful in this cycle since we have to branch anyway. */
LD rWORD1, rOFF8, rSTR1
LD rWORD2, rOFF8, rSTR2
cmpld cr7, rWORD1, rWORD2
b L(dP1e)
/* Remainder is 16 */
.align 4
L(dPs2):
sld rWORD5, rWORD1, rWORD6
sld rWORD6, rWORD2, rWORD6
cmpld cr6, rWORD5, rWORD6
blt cr7, L(dP2x)
/* Do something useful in this cycle since we have to branch anyway. */
LD rWORD7, rOFF8, rSTR1
LD rWORD8, rOFF8, rSTR2
cmpld cr5, rWORD7, rWORD8
b L(dP2e)
/* Remainder is 24 */
.align 4
L(dPs3):
sld rWORD3, rWORD1, rWORD6
sld rWORD4, rWORD2, rWORD6
cmpld cr1, rWORD3, rWORD4
b L(dP3e)
/* Count is a multiple of 32, remainder is 0 */
.align 4
L(dPs4):
mtctr r0
sld rWORD1, rWORD1, rWORD6
sld rWORD2, rWORD2, rWORD6
cmpld cr7, rWORD1, rWORD2
b L(dP4e)
/* At this point we know both strings are double word aligned and the
compare length is at least 8 bytes. */
.align 4
L(DWaligned):
andi. r12, rN, 24 /* Get the DW remainder */
srdi r0, rN, 5 /* Divide by 32 */
cmpldi cr1, r12, 16
cmpldi cr7, rN, 32
clrldi rN, rN, 61
beq L(dP4)
bgt cr1, L(dP3)
beq cr1, L(dP2)
/* Remainder is 8 */
.align 4
L(dP1):
mtctr r0
/* Normally we'd use rWORD7/rWORD8 here, but since we might exit early
(8-15 byte compare), we want to use only volatile registers. This
means we can avoid restoring non-volatile registers since we did not
change any on the early exit path. The key here is the non-early
exit path only cares about the condition code (cr5), not about which
register pair was used. */
LD rWORD5, 0, rSTR1
LD rWORD6, 0, rSTR2
cmpld cr5, rWORD5, rWORD6
blt cr7, L(dP1x)
LD rWORD1, rOFF8, rSTR1
LD rWORD2, rOFF8, rSTR2
cmpld cr7, rWORD1, rWORD2
L(dP1e):
LD rWORD3, rOFF16, rSTR1
LD rWORD4, rOFF16, rSTR2
cmpld cr1, rWORD3, rWORD4
LD rWORD5, rOFF24, rSTR1
LD rWORD6, rOFF24, rSTR2
cmpld cr6, rWORD5, rWORD6
bne cr5, L(dLcr5x)
bne cr7, L(dLcr7x)
LD rWORD7, rOFF32, rSTR1
LD rWORD8, rOFF32, rSTR2
addi rSTR1, rSTR1, 32
addi rSTR2, rSTR2, 32
bne cr1, L(dLcr1)
cmpld cr5, rWORD7, rWORD8
bdnz L(dLoop)
bne cr6, L(dLcr6)
ld rWORD8, rWORD8SAVE(r1)
ld rWORD7, rWORD7SAVE(r1)
.align 3
L(dP1x):
sldi. r12, rN, 3
bne cr5, L(dLcr5x)
subfic rN, r12, 64 /* Shift count is 64 - (rN * 8). */
bne L(d00)
ld rOFF8, rOFF8SAVE(r1)
ld rOFF16, rOFF16SAVE(r1)
ld rOFF24, rOFF24SAVE(r1)
ld rOFF32, rOFF32SAVE(r1)
li rRTN, 0
blr
/* Remainder is 16 */
.align 4
L(dP2):
mtctr r0
LD rWORD5, 0, rSTR1
LD rWORD6, 0, rSTR2
cmpld cr6, rWORD5, rWORD6
blt cr7, L(dP2x)
LD rWORD7, rOFF8, rSTR1
LD rWORD8, rOFF8, rSTR2
cmpld cr5, rWORD7, rWORD8
L(dP2e):
LD rWORD1, rOFF16, rSTR1
LD rWORD2, rOFF16, rSTR2
cmpld cr7, rWORD1, rWORD2
LD rWORD3, rOFF24, rSTR1
LD rWORD4, rOFF24, rSTR2
cmpld cr1, rWORD3, rWORD4
addi rSTR1, rSTR1, 8
addi rSTR2, rSTR2, 8
bne cr6, L(dLcr6)
bne cr5, L(dLcr5)
b L(dLoop2)
.align 4
L(dP2x):
LD rWORD3, rOFF8, rSTR1
LD rWORD4, rOFF8, rSTR2
cmpld cr1, rWORD3, rWORD4
sldi. r12, rN, 3
bne cr6, L(dLcr6x)
addi rSTR1, rSTR1, 8
addi rSTR2, rSTR2, 8
bne cr1, L(dLcr1x)
subfic rN, r12, 64 /* Shift count is 64 - (rN * 8). */
bne L(d00)
ld rOFF8, rOFF8SAVE(r1)
ld rOFF16, rOFF16SAVE(r1)
ld rOFF24, rOFF24SAVE(r1)
ld rOFF32, rOFF32SAVE(r1)
li rRTN, 0
blr
/* Remainder is 24 */
.align 4
L(dP3):
mtctr r0
LD rWORD3, 0, rSTR1
LD rWORD4, 0, rSTR2
cmpld cr1, rWORD3, rWORD4
L(dP3e):
LD rWORD5, rOFF8, rSTR1
LD rWORD6, rOFF8, rSTR2
cmpld cr6, rWORD5, rWORD6
blt cr7, L(dP3x)
LD rWORD7, rOFF16, rSTR1
LD rWORD8, rOFF16, rSTR2
cmpld cr5, rWORD7, rWORD8
LD rWORD1, rOFF24, rSTR1
LD rWORD2, rOFF24, rSTR2
cmpld cr7, rWORD1, rWORD2
addi rSTR1, rSTR1, 16
addi rSTR2, rSTR2, 16
bne cr1, L(dLcr1)
bne cr6, L(dLcr6)
b L(dLoop1)
/* Again we are on a early exit path (24-31 byte compare), we want to
only use volatile registers and avoid restoring non-volatile
registers. */
.align 4
L(dP3x):
LD rWORD1, rOFF16, rSTR1
LD rWORD2, rOFF16, rSTR2
cmpld cr7, rWORD1, rWORD2
sldi. r12, rN, 3
bne cr1, L(dLcr1x)
addi rSTR1, rSTR1, 16
addi rSTR2, rSTR2, 16
bne cr6, L(dLcr6x)
subfic rN, r12, 64 /* Shift count is 64 - (rN * 8). */
bne cr7, L(dLcr7x)
bne L(d00)
ld rOFF8, rOFF8SAVE(r1)
ld rOFF16, rOFF16SAVE(r1)
ld rOFF24, rOFF24SAVE(r1)
ld rOFF32, rOFF32SAVE(r1)
li rRTN, 0
blr
/* Count is a multiple of 32, remainder is 0 */
.align 4
L(dP4):
mtctr r0
LD rWORD1, 0, rSTR1
LD rWORD2, 0, rSTR2
cmpld cr7, rWORD1, rWORD2
L(dP4e):
LD rWORD3, rOFF8, rSTR1
LD rWORD4, rOFF8, rSTR2
cmpld cr1, rWORD3, rWORD4
LD rWORD5, rOFF16, rSTR1
LD rWORD6, rOFF16, rSTR2
cmpld cr6, rWORD5, rWORD6
LD rWORD7, rOFF24, rSTR1
LD rWORD8, rOFF24, rSTR2
addi rSTR1, rSTR1, 24
addi rSTR2, rSTR2, 24
cmpld cr5, rWORD7, rWORD8
bne cr7, L(dLcr7)
bne cr1, L(dLcr1)
bdz- L(d24) /* Adjust CTR as we start with +4 */
/* This is the primary loop */
.align 4
L(dLoop):
LD rWORD1, rOFF8, rSTR1
LD rWORD2, rOFF8, rSTR2
cmpld cr1, rWORD3, rWORD4
bne cr6, L(dLcr6)
L(dLoop1):
LD rWORD3, rOFF16, rSTR1
LD rWORD4, rOFF16, rSTR2
cmpld cr6, rWORD5, rWORD6
bne cr5, L(dLcr5)
L(dLoop2):
LD rWORD5, rOFF24, rSTR1
LD rWORD6, rOFF24, rSTR2
cmpld cr5, rWORD7, rWORD8
bne cr7, L(dLcr7)
L(dLoop3):
LD rWORD7, rOFF32, rSTR1
LD rWORD8, rOFF32, rSTR2
addi rSTR1, rSTR1, 32
addi rSTR2, rSTR2, 32
bne cr1, L(dLcr1)
cmpld cr7, rWORD1, rWORD2
bdnz L(dLoop)
L(dL4):
cmpld cr1, rWORD3, rWORD4
bne cr6, L(dLcr6)
cmpld cr6, rWORD5, rWORD6
bne cr5, L(dLcr5)
cmpld cr5, rWORD7, rWORD8
L(d44):
bne cr7, L(dLcr7)
L(d34):
bne cr1, L(dLcr1)
L(d24):
bne cr6, L(dLcr6)
L(d14):
sldi. r12, rN, 3
bne cr5, L(dLcr5)
L(d04):
ld rWORD8, rWORD8SAVE(r1)
ld rWORD7, rWORD7SAVE(r1)
subfic rN, r12, 64 /* Shift count is 64 - (rN * 8). */
beq L(duzeroLength)
/* At this point we have a remainder of 1 to 7 bytes to compare. Since
we are aligned it is safe to load the whole double word, and use
shift right double to eliminate bits beyond the compare length. */
L(d00):
LD rWORD1, rOFF8, rSTR1
LD rWORD2, rOFF8, rSTR2
srd rWORD1, rWORD1, rN
srd rWORD2, rWORD2, rN
cmpld cr7, rWORD1, rWORD2
bne cr7, L(dLcr7x)
ld rOFF8, rOFF8SAVE(r1)
ld rOFF16, rOFF16SAVE(r1)
ld rOFF24, rOFF24SAVE(r1)
ld rOFF32, rOFF32SAVE(r1)
li rRTN, 0
blr
.align 4
L(dLcr7):
ld rWORD8, rWORD8SAVE(r1)
ld rWORD7, rWORD7SAVE(r1)
L(dLcr7x):
ld rOFF8, rOFF8SAVE(r1)
ld rOFF16, rOFF16SAVE(r1)
ld rOFF24, rOFF24SAVE(r1)
ld rOFF32, rOFF32SAVE(r1)
li rRTN, 1
bgtlr cr7
li rRTN, -1
blr
.align 4
L(dLcr1):
ld rWORD8, rWORD8SAVE(r1)
ld rWORD7, rWORD7SAVE(r1)
L(dLcr1x):
ld rOFF8, rOFF8SAVE(r1)
ld rOFF16, rOFF16SAVE(r1)
ld rOFF24, rOFF24SAVE(r1)
ld rOFF32, rOFF32SAVE(r1)
li rRTN, 1
bgtlr cr1
li rRTN, -1
blr
.align 4
L(dLcr6):
ld rWORD8, rWORD8SAVE(r1)
ld rWORD7, rWORD7SAVE(r1)
L(dLcr6x):
ld rOFF8, rOFF8SAVE(r1)
ld rOFF16, rOFF16SAVE(r1)
ld rOFF24, rOFF24SAVE(r1)
ld rOFF32, rOFF32SAVE(r1)
li rRTN, 1
bgtlr cr6
li rRTN, -1
blr
.align 4
L(dLcr5):
ld rWORD8, rWORD8SAVE(r1)
ld rWORD7, rWORD7SAVE(r1)
L(dLcr5x):
ld rOFF8, rOFF8SAVE(r1)
ld rOFF16, rOFF16SAVE(r1)
ld rOFF24, rOFF24SAVE(r1)
ld rOFF32, rOFF32SAVE(r1)
li rRTN, 1
bgtlr cr5
li rRTN, -1
blr
.align 4
L(bytealigned):
mtctr rN
/* We need to prime this loop. This loop is swing modulo scheduled
to avoid pipe delays. The dependent instruction latencies (load to
compare to conditional branch) is 2 to 3 cycles. In this loop each
dispatch group ends in a branch and takes 1 cycle. Effectively
the first iteration of the loop only serves to load operands and
branches based on compares are delayed until the next loop.
So we must precondition some registers and condition codes so that
we don't exit the loop early on the first iteration. */
lbz rWORD1, 0(rSTR1)
lbz rWORD2, 0(rSTR2)
bdz L(b11)
cmpld cr7, rWORD1, rWORD2
lbz rWORD3, 1(rSTR1)
lbz rWORD4, 1(rSTR2)
bdz L(b12)
cmpld cr1, rWORD3, rWORD4
lbzu rWORD5, 2(rSTR1)
lbzu rWORD6, 2(rSTR2)
bdz L(b13)
.align 4
L(bLoop):
lbzu rWORD1, 1(rSTR1)
lbzu rWORD2, 1(rSTR2)
bne cr7, L(bLcr7)
cmpld cr6, rWORD5, rWORD6
bdz L(b3i)
lbzu rWORD3, 1(rSTR1)
lbzu rWORD4, 1(rSTR2)
bne cr1, L(bLcr1)
cmpld cr7, rWORD1, rWORD2
bdz L(b2i)
lbzu rWORD5, 1(rSTR1)
lbzu rWORD6, 1(rSTR2)
bne cr6, L(bLcr6)
cmpld cr1, rWORD3, rWORD4
bdnz L(bLoop)
/* We speculatively loading bytes before we have tested the previous
bytes. But we must avoid overrunning the length (in the ctr) to
prevent these speculative loads from causing a segfault. In this
case the loop will exit early (before the all pending bytes are
tested. In this case we must complete the pending operations
before returning. */
L(b1i):
bne cr7, L(bLcr7)
bne cr1, L(bLcr1)
b L(bx56)
.align 4
L(b2i):
bne cr6, L(bLcr6)
bne cr7, L(bLcr7)
b L(bx34)
.align 4
L(b3i):
bne cr1, L(bLcr1)
bne cr6, L(bLcr6)
b L(bx12)
.align 4
L(bLcr7):
li rRTN, 1
bgtlr cr7
li rRTN, -1
blr
L(bLcr1):
li rRTN, 1
bgtlr cr1
li rRTN, -1
blr
L(bLcr6):
li rRTN, 1
bgtlr cr6
li rRTN, -1
blr
L(b13):
bne cr7, L(bx12)
bne cr1, L(bx34)
L(bx56):
sub rRTN, rWORD5, rWORD6
blr
nop
L(b12):
bne cr7, L(bx12)
L(bx34):
sub rRTN, rWORD3, rWORD4
blr
L(b11):
L(bx12):
sub rRTN, rWORD1, rWORD2
blr
.align 4
L(zeroLength):
li rRTN, 0
blr
.align 4
/* At this point we know the strings have different alignment and the
compare length is at least 8 bytes. r12 contains the low order
3 bits of rSTR1 and cr5 contains the result of the logical compare
of r12 to 0. If r12 == 0 then rStr1 is double word
aligned and can perform the DWunaligned loop.
Otherwise we know that rSTR1 is not already DW aligned yet.
So we can force the string addresses to the next lower DW
boundary and special case this first DW using shift left to
eliminate bits preceding the first byte. Since we want to join the
normal (DWaligned) compare loop, starting at the second double word,
we need to adjust the length (rN) and special case the loop
versioning for the first DW. This ensures that the loop count is
correct and the first DW (shifted) is in the expected resister pair. */
L(unaligned):
std rSHL, rSHLSAVE(r1)
cfi_offset(rSHL, rSHLSAVE)
clrldi rSHL, rSTR2, 61
beq cr6, L(duzeroLength)
std rSHR, rSHRSAVE(r1)
cfi_offset(rSHR, rSHRSAVE)
beq cr5, L(DWunaligned)
std rWORD8_SHIFT, rWORD8SHIFTSAVE(r1)
cfi_offset(rWORD8_SHIFT, rWORD8SHIFTSAVE)
/* Adjust the logical start of rSTR2 to compensate for the extra bits
in the 1st rSTR1 DW. */
sub rWORD8_SHIFT, rSTR2, r12
/* But do not attempt to address the DW before that DW that contains
the actual start of rSTR2. */
clrrdi rSTR2, rSTR2, 3
std rWORD2_SHIFT, rWORD2SHIFTSAVE(r1)
cfi_offset(rWORD2_SHIFT, rWORD2SHIFTSAVE)
/* Compute the left/right shift counts for the unaligned rSTR2,
compensating for the logical (DW aligned) start of rSTR1. */
clrldi rSHL, rWORD8_SHIFT, 61
clrrdi rSTR1, rSTR1, 3
std rWORD4_SHIFT, rWORD4SHIFTSAVE(r1)
cfi_offset(rWORD4_SHIFT, rWORD4SHIFTSAVE)
sldi rSHL, rSHL, 3
cmpld cr5, rWORD8_SHIFT, rSTR2
add rN, rN, r12
sldi rWORD6, r12, 3
std rWORD6_SHIFT, rWORD6SHIFTSAVE(r1)
cfi_offset(rWORD6_SHIFT, rWORD6SHIFTSAVE)
subfic rSHR, rSHL, 64
srdi r0, rN, 5 /* Divide by 32 */
andi. r12, rN, 24 /* Get the DW remainder */
/* We normally need to load 2 DWs to start the unaligned rSTR2, but in
this special case those bits may be discarded anyway. Also we
must avoid loading a DW where none of the bits are part of rSTR2 as
this may cross a page boundary and cause a page fault. */
li rWORD8, 0
blt cr5, L(dus0)
LD rWORD8, 0, rSTR2
addi rSTR2, rSTR2, 8
sld rWORD8, rWORD8, rSHL
L(dus0):
LD rWORD1, 0, rSTR1
LD rWORD2, 0, rSTR2
cmpldi cr1, r12, 16
cmpldi cr7, rN, 32
srd r12, rWORD2, rSHR
clrldi rN, rN, 61
beq L(duPs4)
mtctr r0
or rWORD8, r12, rWORD8
bgt cr1, L(duPs3)
beq cr1, L(duPs2)
/* Remainder is 8 */
.align 4
L(dusP1):
sld rWORD8_SHIFT, rWORD2, rSHL
sld rWORD7, rWORD1, rWORD6
sld rWORD8, rWORD8, rWORD6
bge cr7, L(duP1e)
/* At this point we exit early with the first double word compare
complete and remainder of 0 to 7 bytes. See L(du14) for details on
how we handle the remaining bytes. */
cmpld cr5, rWORD7, rWORD8
sldi. rN, rN, 3
bne cr5, L(duLcr5)
cmpld cr7, rN, rSHR
beq L(duZeroReturn)
li r0, 0
ble cr7, L(dutrim)
LD rWORD2, rOFF8, rSTR2
srd r0, rWORD2, rSHR
b L(dutrim)
/* Remainder is 16 */
.align 4
L(duPs2):
sld rWORD6_SHIFT, rWORD2, rSHL
sld rWORD5, rWORD1, rWORD6
sld rWORD6, rWORD8, rWORD6
b L(duP2e)
/* Remainder is 24 */
.align 4
L(duPs3):
sld rWORD4_SHIFT, rWORD2, rSHL
sld rWORD3, rWORD1, rWORD6
sld rWORD4, rWORD8, rWORD6
b L(duP3e)
/* Count is a multiple of 32, remainder is 0 */
.align 4
L(duPs4):
mtctr r0
or rWORD8, r12, rWORD8
sld rWORD2_SHIFT, rWORD2, rSHL
sld rWORD1, rWORD1, rWORD6
sld rWORD2, rWORD8, rWORD6
b L(duP4e)
/* At this point we know rSTR1 is double word aligned and the
compare length is at least 8 bytes. */
.align 4
L(DWunaligned):
std rWORD8_SHIFT, rWORD8SHIFTSAVE(r1)
cfi_offset(rWORD8_SHIFT, rWORD8SHIFTSAVE)
clrrdi rSTR2, rSTR2, 3
std rWORD2_SHIFT, rWORD2SHIFTSAVE(r1)
cfi_offset(rWORD2_SHIFT, rWORD2SHIFTSAVE)
srdi r0, rN, 5 /* Divide by 32 */
std rWORD4_SHIFT, rWORD4SHIFTSAVE(r1)
cfi_offset(rWORD4_SHIFT, rWORD4SHIFTSAVE)
andi. r12, rN, 24 /* Get the DW remainder */
std rWORD6_SHIFT, rWORD6SHIFTSAVE(r1)
cfi_offset(rWORD6_SHIFT, rWORD6SHIFTSAVE)
sldi rSHL, rSHL, 3
LD rWORD6, 0, rSTR2
LD rWORD8, rOFF8, rSTR2
addi rSTR2, rSTR2, 8
cmpldi cr1, r12, 16
cmpldi cr7, rN, 32
clrldi rN, rN, 61
subfic rSHR, rSHL, 64
sld rWORD6_SHIFT, rWORD6, rSHL
beq L(duP4)
mtctr r0
bgt cr1, L(duP3)
beq cr1, L(duP2)
/* Remainder is 8 */
.align 4
L(duP1):
srd r12, rWORD8, rSHR
LD rWORD7, 0, rSTR1
sld rWORD8_SHIFT, rWORD8, rSHL
or rWORD8, r12, rWORD6_SHIFT
blt cr7, L(duP1x)
L(duP1e):
LD rWORD1, rOFF8, rSTR1
LD rWORD2, rOFF8, rSTR2
cmpld cr5, rWORD7, rWORD8
srd r0, rWORD2, rSHR
sld rWORD2_SHIFT, rWORD2, rSHL
or rWORD2, r0, rWORD8_SHIFT
LD rWORD3, rOFF16, rSTR1
LD rWORD4, rOFF16, rSTR2
cmpld cr7, rWORD1, rWORD2
srd r12, rWORD4, rSHR
sld rWORD4_SHIFT, rWORD4, rSHL
bne cr5, L(duLcr5)
or rWORD4, r12, rWORD2_SHIFT
LD rWORD5, rOFF24, rSTR1
LD rWORD6, rOFF24, rSTR2
cmpld cr1, rWORD3, rWORD4
srd r0, rWORD6, rSHR
sld rWORD6_SHIFT, rWORD6, rSHL
bne cr7, L(duLcr7)
or rWORD6, r0, rWORD4_SHIFT
cmpld cr6, rWORD5, rWORD6
b L(duLoop3)
.align 4
/* At this point we exit early with the first double word compare
complete and remainder of 0 to 7 bytes. See L(du14) for details on
how we handle the remaining bytes. */
L(duP1x):
cmpld cr5, rWORD7, rWORD8
sldi. rN, rN, 3
bne cr5, L(duLcr5)
cmpld cr7, rN, rSHR
beq L(duZeroReturn)
li r0, 0
ble cr7, L(dutrim)
LD rWORD2, rOFF8, rSTR2
srd r0, rWORD2, rSHR
b L(dutrim)
/* Remainder is 16 */
.align 4
L(duP2):
srd r0, rWORD8, rSHR
LD rWORD5, 0, rSTR1
or rWORD6, r0, rWORD6_SHIFT
sld rWORD6_SHIFT, rWORD8, rSHL
L(duP2e):
LD rWORD7, rOFF8, rSTR1
LD rWORD8, rOFF8, rSTR2
cmpld cr6, rWORD5, rWORD6
srd r12, rWORD8, rSHR
sld rWORD8_SHIFT, rWORD8, rSHL
or rWORD8, r12, rWORD6_SHIFT
blt cr7, L(duP2x)
LD rWORD1, rOFF16, rSTR1
LD rWORD2, rOFF16, rSTR2
cmpld cr5, rWORD7, rWORD8
bne cr6, L(duLcr6)
srd r0, rWORD2, rSHR
sld rWORD2_SHIFT, rWORD2, rSHL
or rWORD2, r0, rWORD8_SHIFT
LD rWORD3, rOFF24, rSTR1
LD rWORD4, rOFF24, rSTR2
cmpld cr7, rWORD1, rWORD2
bne cr5, L(duLcr5)
srd r12, rWORD4, rSHR
sld rWORD4_SHIFT, rWORD4, rSHL
or rWORD4, r12, rWORD2_SHIFT
addi rSTR1, rSTR1, 8
addi rSTR2, rSTR2, 8
cmpld cr1, rWORD3, rWORD4
b L(duLoop2)
.align 4
L(duP2x):
cmpld cr5, rWORD7, rWORD8
addi rSTR1, rSTR1, 8
addi rSTR2, rSTR2, 8
bne cr6, L(duLcr6)
sldi. rN, rN, 3
bne cr5, L(duLcr5)
cmpld cr7, rN, rSHR
beq L(duZeroReturn)
li r0, 0
ble cr7, L(dutrim)
LD rWORD2, rOFF8, rSTR2
srd r0, rWORD2, rSHR
b L(dutrim)
/* Remainder is 24 */
.align 4
L(duP3):
srd r12, rWORD8, rSHR
LD rWORD3, 0, rSTR1
sld rWORD4_SHIFT, rWORD8, rSHL
or rWORD4, r12, rWORD6_SHIFT
L(duP3e):
LD rWORD5, rOFF8, rSTR1
LD rWORD6, rOFF8, rSTR2
cmpld cr1, rWORD3, rWORD4
srd r0, rWORD6, rSHR
sld rWORD6_SHIFT, rWORD6, rSHL
or rWORD6, r0, rWORD4_SHIFT
LD rWORD7, rOFF16, rSTR1
LD rWORD8, rOFF16, rSTR2
cmpld cr6, rWORD5, rWORD6
bne cr1, L(duLcr1)
srd r12, rWORD8, rSHR
sld rWORD8_SHIFT, rWORD8, rSHL
or rWORD8, r12, rWORD6_SHIFT
blt cr7, L(duP3x)
LD rWORD1, rOFF24, rSTR1
LD rWORD2, rOFF24, rSTR2
cmpld cr5, rWORD7, rWORD8
bne cr6, L(duLcr6)
srd r0, rWORD2, rSHR
sld rWORD2_SHIFT, rWORD2, rSHL
or rWORD2, r0, rWORD8_SHIFT
addi rSTR1, rSTR1, 16
addi rSTR2, rSTR2, 16
cmpld cr7, rWORD1, rWORD2
b L(duLoop1)
.align 4
L(duP3x):
addi rSTR1, rSTR1, 16
addi rSTR2, rSTR2, 16
cmpld cr5, rWORD7, rWORD8
bne cr6, L(duLcr6)
sldi. rN, rN, 3
bne cr5, L(duLcr5)
cmpld cr7, rN, rSHR
beq L(duZeroReturn)
li r0, 0
ble cr7, L(dutrim)
LD rWORD2, rOFF8, rSTR2
srd r0, rWORD2, rSHR
b L(dutrim)
/* Count is a multiple of 32, remainder is 0 */
.align 4
L(duP4):
mtctr r0
srd r0, rWORD8, rSHR
LD rWORD1, 0, rSTR1
sld rWORD2_SHIFT, rWORD8, rSHL
or rWORD2, r0, rWORD6_SHIFT
L(duP4e):
LD rWORD3, rOFF8, rSTR1
LD rWORD4, rOFF8, rSTR2
cmpld cr7, rWORD1, rWORD2
srd r12, rWORD4, rSHR
sld rWORD4_SHIFT, rWORD4, rSHL
or rWORD4, r12, rWORD2_SHIFT
LD rWORD5, rOFF16, rSTR1
LD rWORD6, rOFF16, rSTR2
cmpld cr1, rWORD3, rWORD4
bne cr7, L(duLcr7)
srd r0, rWORD6, rSHR
sld rWORD6_SHIFT, rWORD6, rSHL
or rWORD6, r0, rWORD4_SHIFT
LD rWORD7, rOFF24, rSTR1
LD rWORD8, rOFF24, rSTR2
addi rSTR1, rSTR1, 24
addi rSTR2, rSTR2, 24
cmpld cr6, rWORD5, rWORD6
bne cr1, L(duLcr1)
srd r12, rWORD8, rSHR
sld rWORD8_SHIFT, rWORD8, rSHL
or rWORD8, r12, rWORD6_SHIFT
cmpld cr5, rWORD7, rWORD8
bdz L(du24) /* Adjust CTR as we start with +4 */
/* This is the primary loop */
.align 4
L(duLoop):
LD rWORD1, rOFF8, rSTR1
LD rWORD2, rOFF8, rSTR2
cmpld cr1, rWORD3, rWORD4
bne cr6, L(duLcr6)
srd r0, rWORD2, rSHR
sld rWORD2_SHIFT, rWORD2, rSHL
or rWORD2, r0, rWORD8_SHIFT
L(duLoop1):
LD rWORD3, rOFF16, rSTR1
LD rWORD4, rOFF16, rSTR2
cmpld cr6, rWORD5, rWORD6
bne cr5, L(duLcr5)
srd r12, rWORD4, rSHR
sld rWORD4_SHIFT, rWORD4, rSHL
or rWORD4, r12, rWORD2_SHIFT
L(duLoop2):
LD rWORD5, rOFF24, rSTR1
LD rWORD6, rOFF24, rSTR2
cmpld cr5, rWORD7, rWORD8
bne cr7, L(duLcr7)
srd r0, rWORD6, rSHR
sld rWORD6_SHIFT, rWORD6, rSHL
or rWORD6, r0, rWORD4_SHIFT
L(duLoop3):
LD rWORD7, rOFF32, rSTR1
LD rWORD8, rOFF32, rSTR2
addi rSTR1, rSTR1, 32
addi rSTR2, rSTR2, 32
cmpld cr7, rWORD1, rWORD2
bne cr1, L(duLcr1)
srd r12, rWORD8, rSHR
sld rWORD8_SHIFT, rWORD8, rSHL
or rWORD8, r12, rWORD6_SHIFT
bdnz L(duLoop)
L(duL4):
cmpld cr1, rWORD3, rWORD4
bne cr6, L(duLcr6)
cmpld cr6, rWORD5, rWORD6
bne cr5, L(duLcr5)
cmpld cr5, rWORD7, rWORD8
L(du44):
bne cr7, L(duLcr7)
L(du34):
bne cr1, L(duLcr1)
L(du24):
bne cr6, L(duLcr6)
L(du14):
sldi. rN, rN, 3
bne cr5, L(duLcr5)
/* At this point we have a remainder of 1 to 7 bytes to compare. We use
shift right double to eliminate bits beyond the compare length.
However it may not be safe to load rWORD2 which may be beyond the
string length. So we compare the bit length of the remainder to
the right shift count (rSHR). If the bit count is less than or equal
we do not need to load rWORD2 (all significant bits are already in
rWORD8_SHIFT). */
cmpld cr7, rN, rSHR
beq L(duZeroReturn)
li r0, 0
ble cr7, L(dutrim)
LD rWORD2, rOFF8, rSTR2
srd r0, rWORD2, rSHR
.align 4
L(dutrim):
LD rWORD1, rOFF8, rSTR1
ld rWORD8, -8(r1)
subfic rN, rN, 64 /* Shift count is 64 - (rN * 8). */
or rWORD2, r0, rWORD8_SHIFT
ld rWORD7, rWORD7SAVE(r1)
ld rSHL, rSHLSAVE(r1)
srd rWORD1, rWORD1, rN
srd rWORD2, rWORD2, rN
ld rSHR, rSHRSAVE(r1)
ld rWORD8_SHIFT, rWORD8SHIFTSAVE(r1)
li rRTN, 0
cmpld cr7, rWORD1, rWORD2
ld rWORD2_SHIFT, rWORD2SHIFTSAVE(r1)
ld rWORD4_SHIFT, rWORD4SHIFTSAVE(r1)
beq cr7, L(dureturn24)
li rRTN, 1
ld rWORD6_SHIFT, rWORD6SHIFTSAVE(r1)
ld rOFF8, rOFF8SAVE(r1)
ld rOFF16, rOFF16SAVE(r1)
ld rOFF24, rOFF24SAVE(r1)
ld rOFF32, rOFF32SAVE(r1)
bgtlr cr7
li rRTN, -1
blr
.align 4
L(duLcr7):
ld rWORD8, rWORD8SAVE(r1)
ld rWORD7, rWORD7SAVE(r1)
li rRTN, 1
bgt cr7, L(dureturn29)
ld rSHL, rSHLSAVE(r1)
ld rSHR, rSHRSAVE(r1)
li rRTN, -1
b L(dureturn27)
.align 4
L(duLcr1):
ld rWORD8, rWORD8SAVE(r1)
ld rWORD7, rWORD7SAVE(r1)
li rRTN, 1
bgt cr1, L(dureturn29)
ld rSHL, rSHLSAVE(r1)
ld rSHR, rSHRSAVE(r1)
li rRTN, -1
b L(dureturn27)
.align 4
L(duLcr6):
ld rWORD8, rWORD8SAVE(r1)
ld rWORD7, rWORD7SAVE(r1)
li rRTN, 1
bgt cr6, L(dureturn29)
ld rSHL, rSHLSAVE(r1)
ld rSHR, rSHRSAVE(r1)
li rRTN, -1
b L(dureturn27)
.align 4
L(duLcr5):
ld rWORD8, rWORD8SAVE(r1)
ld rWORD7, rWORD7SAVE(r1)
li rRTN, 1
bgt cr5, L(dureturn29)
ld rSHL, rSHLSAVE(r1)
ld rSHR, rSHRSAVE(r1)
li rRTN, -1
b L(dureturn27)
.align 3
L(duZeroReturn):
li rRTN, 0
.align 4
L(dureturn):
ld rWORD8, rWORD8SAVE(r1)
ld rWORD7, rWORD7SAVE(r1)
L(dureturn29):
ld rSHL, rSHLSAVE(r1)
ld rSHR, rSHRSAVE(r1)
L(dureturn27):
ld rWORD8_SHIFT, rWORD8SHIFTSAVE(r1)
ld rWORD2_SHIFT, rWORD2SHIFTSAVE(r1)
ld rWORD4_SHIFT, rWORD4SHIFTSAVE(r1)
L(dureturn24):
ld rWORD6_SHIFT, rWORD6SHIFTSAVE(r1)
ld rOFF8, rOFF8SAVE(r1)
ld rOFF16, rOFF16SAVE(r1)
ld rOFF24, rOFF24SAVE(r1)
ld rOFF32, rOFF32SAVE(r1)
blr
L(duzeroLength):
ld rOFF8, rOFF8SAVE(r1)
ld rOFF16, rOFF16SAVE(r1)
ld rOFF24, rOFF24SAVE(r1)
ld rOFF32, rOFF32SAVE(r1)
li rRTN, 0
blr
END (memcmp)
libc_hidden_builtin_def (memcmp)
weak_alias (memcmp, bcmp)
|