-
Notifications
You must be signed in to change notification settings - Fork 461
/
asm_avr.inc
1089 lines (942 loc) · 30.8 KB
/
asm_avr.inc
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
/* Copyright 2015, Kenneth MacKay. Licensed under the BSD 2-clause license. */
#ifndef _UECC_ASM_AVR_H_
#define _UECC_ASM_AVR_H_
#if (uECC_SUPPORTS_secp256r1 || uECC_SUPPORTS_secp256k1)
#define uECC_MIN_WORDS 32
#endif
#if uECC_SUPPORTS_secp224r1
#undef uECC_MIN_WORDS
#define uECC_MIN_WORDS 28
#endif
#if uECC_SUPPORTS_secp192r1
#undef uECC_MIN_WORDS
#define uECC_MIN_WORDS 24
#endif
#if uECC_SUPPORTS_secp160r1
#undef uECC_MIN_WORDS
#define uECC_MIN_WORDS 20
#endif
#if __AVR_HAVE_EIJMP_EICALL__
#define IJMP "eijmp \n\t"
#else
#define IJMP "ijmp \n\t"
#endif
#if (uECC_OPTIMIZATION_LEVEL >= 2)
uECC_VLI_API void uECC_vli_clear(uECC_word_t *vli, wordcount_t num_words) {
volatile uECC_word_t *v = vli;
__asm__ volatile (
#if (uECC_MAX_WORDS != uECC_MIN_WORDS)
"ldi r30, pm_lo8(1f) \n\t"
"ldi r31, pm_hi8(1f) \n\t"
"sub r30, %[num] \n\t"
"sbc r31, __zero_reg__ \n\t"
IJMP
#endif
REPEAT(uECC_MAX_WORDS, "st x+, __zero_reg__ \n\t")
"1: \n\t"
: "+x" (v)
: [num] "r" (num_words)
:
#if (uECC_MAX_WORDS != uECC_MIN_WORDS)
"r30", "r31", "cc"
#endif
);
}
#define asm_clear 1
uECC_VLI_API void uECC_vli_set(uECC_word_t *dest, const uECC_word_t *src, wordcount_t num_words) {
volatile uECC_word_t *d = dest;
__asm__ volatile (
#if (uECC_MAX_WORDS != uECC_MIN_WORDS)
"ldi r30, pm_lo8(1f) \n\t"
"ldi r31, pm_hi8(1f) \n\t"
"sub r30, %[num] \n\t"
"sbc r31, __zero_reg__ \n\t"
IJMP
#endif
REPEAT(uECC_MAX_WORDS,
"ld r0, y+ \n\t"
"st x+, r0 \n\t")
"1: \n\t"
: "+x" (d), "+y" (src)
: [num] "r" ((uint8_t)(num_words * 2))
: "r0"
#if (uECC_MAX_WORDS != uECC_MIN_WORDS)
, "r30", "r31", "cc"
#endif
);
}
#define asm_set 1
uECC_VLI_API void uECC_vli_rshift1(uECC_word_t *vli, wordcount_t num_words) {
volatile uECC_word_t *v = vli;
__asm__ volatile (
#if (uECC_MAX_WORDS != uECC_MIN_WORDS)
"ldi r30, pm_lo8(1f) \n\t"
"ldi r31, pm_hi8(1f) \n\t"
"sub r30, %[jump] \n\t"
"sbc r31, __zero_reg__ \n\t"
#endif
"add r26, %[num] \n\t"
"adc r27, __zero_reg__ \n\t"
"ld r0, -x \n\t"
"lsr r0 \n\t"
"st x, r0 \n\t"
#if (uECC_MAX_WORDS != uECC_MIN_WORDS)
IJMP
#endif
REPEAT(DEC(uECC_MAX_WORDS),
"ld r0, -x \n\t"
"ror r0 \n\t"
"st x, r0 \n\t")
"1: \n\t"
: "+x" (v)
#if (uECC_MAX_WORDS != uECC_MIN_WORDS)
: [num] "r" (num_words), [jump] "r" ((uint8_t)(3 * (num_words - 1)))
: "r0", "r30", "r31", "cc"
#else
: [num] "r" (num_words)
: "r0", "cc"
#endif
);
}
#define asm_rshift1 1
#define ADD_RJPM_TABLE(N) \
"movw r30, %A[result] \n\t" \
"rjmp add_%=_" #N " \n\t"
#define ADD_RJPM_DEST(N) \
"add_%=_" #N ":" \
"ld %[clb], x+ \n\t" \
"ld %[rb], y+ \n\t" \
"adc %[clb], %[rb] \n\t" \
"st z+, %[clb] \n\t"
uECC_VLI_API uECC_word_t uECC_vli_add(uECC_word_t *result,
const uECC_word_t *left,
const uECC_word_t *right,
wordcount_t num_words) {
volatile uECC_word_t *r = result;
uint8_t carry;
uint8_t right_byte;
__asm__ volatile (
#if (uECC_MAX_WORDS != uECC_MIN_WORDS)
"ldi r30, pm_lo8(add_%=_" STR(uECC_MAX_WORDS) ") \n\t"
"ldi r31, pm_hi8(add_%=_" STR(uECC_MAX_WORDS) ") \n\t"
"sub r30, %[num] \n\t"
"sbc r31, __zero_reg__ \n\t"
#endif
"clc \n\t"
#if (uECC_MAX_WORDS != uECC_MIN_WORDS)
IJMP
REPEATM(uECC_MAX_WORDS, ADD_RJPM_TABLE)
#endif
REPEATM(uECC_MAX_WORDS, ADD_RJPM_DEST)
"mov %[clb], __zero_reg__ \n\t"
"adc %[clb], %[clb] \n\t" /* Store carry bit. */
: "+x" (left), "+y" (right),
[clb] "=&r" (carry), [rb] "=&r" (right_byte)
: [result] "r" (r), [num] "r" ((uint8_t)(num_words * 2))
: "r30", "r31", "cc"
);
return carry;
}
#define asm_add 1
#define SUB_RJPM_TABLE(N) \
"movw r30, %A[result] \n\t" \
"rjmp sub_%=_" #N " \n\t"
#define SUB_RJPM_DEST(N) \
"sub_%=_" #N ":" \
"ld %[clb], x+ \n\t" \
"ld %[rb], y+ \n\t" \
"sbc %[clb], %[rb] \n\t" \
"st z+, %[clb] \n\t"
uECC_VLI_API uECC_word_t uECC_vli_sub(uECC_word_t *result,
const uECC_word_t *left,
const uECC_word_t *right,
wordcount_t num_words) {
volatile uECC_word_t *r = result;
uint8_t carry;
uint8_t right_byte;
__asm__ volatile (
#if (uECC_MAX_WORDS != uECC_MIN_WORDS)
"ldi r30, pm_lo8(sub_%=_" STR(uECC_MAX_WORDS) ") \n\t"
"ldi r31, pm_hi8(sub_%=_" STR(uECC_MAX_WORDS) ") \n\t"
"sub r30, %[num] \n\t"
"sbc r31, __zero_reg__ \n\t"
#endif
"clc \n\t"
#if (uECC_MAX_WORDS != uECC_MIN_WORDS)
IJMP
REPEATM(uECC_MAX_WORDS, SUB_RJPM_TABLE)
#endif
REPEATM(uECC_MAX_WORDS, SUB_RJPM_DEST)
"mov %[clb], __zero_reg__ \n\t"
"adc %[clb], %[clb] \n\t" /* Store carry bit. */
: "+x" (left), "+y" (right),
[clb] "=&r" (carry), [rb] "=&r" (right_byte)
: [result] "r" (r), [num] "r" ((uint8_t)(num_words * 2))
: "r30", "r31", "cc"
);
return carry;
}
#define asm_sub 1
#if (uECC_OPTIMIZATION_LEVEL >= 3)
#include "asm_avr_mult_square.inc"
__attribute((noinline))
uECC_VLI_API void uECC_vli_mult(uECC_word_t *result,
const uECC_word_t *left,
const uECC_word_t *right,
wordcount_t num_words) {
/* num_words should already be in r18. */
register wordcount_t r18 __asm__("r18") = num_words;
__asm__ volatile (
"push r18 \n\t"
#if (uECC_MIN_WORDS == 20)
FAST_MULT_ASM_20
"pop r18 \n\t"
#if (uECC_MAX_WORDS > 20)
FAST_MULT_ASM_20_TO_24
#endif
#if (uECC_MAX_WORDS > 24)
FAST_MULT_ASM_24_TO_28
#endif
#if (uECC_MAX_WORDS > 28)
FAST_MULT_ASM_28_TO_32
#endif
#elif (uECC_MIN_WORDS == 24)
FAST_MULT_ASM_24
"pop r18 \n\t"
#if (uECC_MAX_WORDS > 24)
FAST_MULT_ASM_24_TO_28
#endif
#if (uECC_MAX_WORDS > 28)
FAST_MULT_ASM_28_TO_32
#endif
#elif (uECC_MIN_WORDS == 28)
FAST_MULT_ASM_28
"pop r18 \n\t"
#if (uECC_MAX_WORDS > 28)
FAST_MULT_ASM_28_TO_32
#endif
#elif (uECC_MIN_WORDS == 32)
FAST_MULT_ASM_32
"pop r18 \n\t"
#endif
"2: \n\t"
"eor r1, r1 \n\t"
: "+x" (left), "+y" (right), "+z" (result)
: "r" (r18)
: "r0", "r2", "r3", "r4", "r5", "r6", "r7", "r8", "r9", "r10",
"r11", "r12", "r13", "r14", "r15", "r16", "r17", "r19", "r20",
"r21", "r22", "r23", "r24", "r25", "cc"
);
}
#define asm_mult 1
#if uECC_SQUARE_FUNC
__attribute((noinline))
uECC_VLI_API void uECC_vli_square(uECC_word_t *result,
const uECC_word_t *left,
wordcount_t num_words) {
/* num_words should already be in r20. */
register wordcount_t r20 __asm__("r20") = num_words;
__asm__ volatile (
"push r20 \n\t"
#if (uECC_MIN_WORDS == 20)
FAST_SQUARE_ASM_20
"pop r20 \n\t"
#if (uECC_MAX_WORDS > 20)
FAST_SQUARE_ASM_20_TO_24
#endif
#if (uECC_MAX_WORDS > 24)
FAST_SQUARE_ASM_24_TO_28
#endif
#if (uECC_MAX_WORDS > 28)
FAST_SQUARE_ASM_28_TO_32
#endif
#elif (uECC_MIN_WORDS == 24)
FAST_SQUARE_ASM_24
"pop r20 \n\t"
#if (uECC_MAX_WORDS > 24)
FAST_SQUARE_ASM_24_TO_28
#endif
#if (uECC_MAX_WORDS > 28)
FAST_SQUARE_ASM_28_TO_32
#endif
#elif (uECC_MIN_WORDS == 28)
FAST_SQUARE_ASM_28
"pop r20 \n\t"
#if (uECC_MAX_WORDS > 28)
FAST_SQUARE_ASM_28_TO_32
#endif
#elif (uECC_MIN_WORDS == 32)
FAST_SQUARE_ASM_32
"pop r20 \n\t"
#endif
"2: \n\t"
"eor r1, r1 \n\t"
: "+x" (left), "+z" (result)
: "r" (r20)
: "r0", "r2", "r3", "r4", "r5", "r6", "r7", "r8", "r9", "r10",
"r11", "r12", "r13", "r14", "r15", "r16", "r17", "r18", "r19",
"r21", "r22", "r23", "r24", "r25", "r28", "r29", "cc"
);
}
#define asm_square 1
#endif /* uECC_SQUARE_FUNC */
#endif /* (uECC_OPTIMIZATION_LEVEL >= 3) */
#if uECC_SUPPORTS_secp160r1
static const struct uECC_Curve_t curve_secp160r1;
static void vli_mmod_fast_secp160r1(uECC_word_t *result, uECC_word_t *product) {
uint8_t carry = 0;
__asm__ volatile (
"in r30, __SP_L__ \n\t"
"in r31, __SP_H__ \n\t"
"sbiw r30, 24 \n\t"
"in r0, __SREG__ \n\t"
"cli \n\t"
"out __SP_H__, r31 \n\t"
"out __SREG__, r0 \n\t"
"out __SP_L__, r30 \n\t"
"adiw r30, 25 \n\t" /* we are shifting by 31 bits, so shift over 4 bytes
(+ 1 since z initially points below the stack) */
"adiw r26, 40 \n\t" /* end of product */
"ld r18, -x \n\t" /* Load word. */
"lsr r18 \n\t" /* Shift. */
"st -z, r18 \n\t" /* Store the first result word. */
/* Now we just do the remaining words with the carry bit (using ROR) */
REPEAT(19,
"ld r18, -x \n\t"
"ror r18 \n\t"
"st -z, r18 \n\t")
"eor r18, r18 \n\t" /* r18 = 0 */
"ror r18 \n\t" /* get last bit */
"st -z, r18 \n\t" /* store it */
"sbiw r30, 3 \n\t" /* move z back to point at tmp */
/* now we add right */
"ld r18, x+ \n\t"
"st z+, r18 \n\t" /* the first 3 bytes do not need to be added */
"ld r18, x+ \n\t"
"st z+, r18 \n\t"
"ld r18, x+ \n\t"
"st z+, r18 \n\t"
"ld r18, x+ \n\t"
"ld r19, z \n\t"
"add r18, r19 \n\t"
"st z+, r18 \n\t"
/* Now we just do the remaining words with the carry bit (using ADC) */
REPEAT(16,
"ld r18, x+ \n\t"
"ld r19, z \n\t"
"adc r18, r19 \n\t"
"st z+, r18 \n\t")
/* Propagate over the remaining bytes of result */
"ld r18, z \n\t"
"adc r18, r1 \n\t"
"st z+, r18 \n\t"
"ld r18, z \n\t"
"adc r18, r1 \n\t"
"st z+, r18 \n\t"
"ld r18, z \n\t"
"adc r18, r1 \n\t"
"st z+, r18 \n\t"
"ld r18, z \n\t"
"adc r18, r1 \n\t"
"st z+, r18 \n\t"
"sbiw r30, 24 \n\t" /* move z back to point at tmp */
"sbiw r26, 40 \n\t" /* move x back to point at product */
/* add low bytes of tmp to product, storing in result */
"ld r18, z+ \n\t"
"ld r19, x+ \n\t"
"add r18, r19 \n\t"
"st y+, r18 \n\t"
REPEAT(19,
"ld r18, z+ \n\t"
"ld r19, x+ \n\t"
"adc r18, r19 \n\t"
"st y+, r18 \n\t")
"adc %[carry], __zero_reg__ \n\t" /* Store carry bit (carry flag is cleared). */
/* at this point x is at the end of product, y is at the end of result,
z is 20 bytes into tmp */
"sbiw r28, 20 \n\t" /* move y back to point at result */
"adiw r30, 4 \n\t" /* move z to point to the end of tmp */
/* do omega_mult again with the 4 relevant bytes */
/* z points to the end of tmp, x points to the end of product */
"ld r18, -z \n\t" /* Load word. */
"lsr r18 \n\t" /* Shift. */
"st -x, r18 \n\t" /* Store the first result word. */
"ld r18, -z \n\t"
"ror r18 \n\t"
"st -x, r18 \n\t"
"ld r18, -z \n\t"
"ror r18 \n\t"
"st -x, r18 \n\t"
"ld r18, -z \n\t"
"ror r18 \n\t"
"st -x, r18 \n\t"
"eor r18, r18 \n\t" /* r18 = 0 */
"ror r18 \n\t" /* get last bit */
"st -x, r18 \n\t" /* store it */
"sbiw r26, 3 \n\t" /* move x back to point at beginning */
/* now we add a copy of the 4 bytes */
"ld r18, z+ \n\t"
"st x+, r18 \n\t" /* the first 3 bytes do not need to be added */
"ld r18, z+ \n\t"
"st x+, r18 \n\t"
"ld r18, z+ \n\t"
"st x+, r18 \n\t"
"ld r18, z+ \n\t"
"ld r19, x \n\t"
"add r18, r19 \n\t"
"st x+, r18 \n\t"
/* Propagate over the remaining bytes */
"ld r18, x \n\t"
"adc r18, r1 \n\t"
"st x+, r18 \n\t"
"ld r18, x \n\t"
"adc r18, r1 \n\t"
"st x+, r18 \n\t"
"ld r18, x \n\t"
"adc r18, r1 \n\t"
"st x+, r18 \n\t"
"ld r18, x \n\t"
"adc r18, r1 \n\t"
"st x+, r18 \n\t"
/* now z points to the end of tmp, x points to the end of product
(y still points at result) */
"sbiw r26, 8 \n\t" /* move x back to point at beginning of actual data */
/* add into result */
"ld r18, x+ \n\t"
"ld r19, y \n\t"
"add r18, r19 \n\t"
"st y+, r18 \n\t"
REPEAT(7,
"ld r18, x+ \n\t"
"ld r19, y \n\t"
"adc r18, r19 \n\t"
"st y+, r18 \n\t")
/* Done adding, now propagate carry bit */
REPEAT(12,
"ld r18, y \n\t"
"adc r18, __zero_reg__ \n\t"
"st y+, r18 \n\t")
"adc %[carry], __zero_reg__ \n\t" /* Store carry bit (carry flag is cleared). */
"sbiw r28, 20 \n\t" /* move y back to point at result */
"sbiw r30, 1 \n\t" /* fix stack pointer */
"in r0, __SREG__ \n\t"
"cli \n\t"
"out __SP_H__, r31 \n\t"
"out __SREG__, r0 \n\t"
"out __SP_L__, r30 \n\t"
: "+x" (product), [carry] "+r" (carry)
: "y" (result)
: "r0", "r18", "r19", "r30", "r31", "cc"
);
if (carry > 0) {
--carry;
uECC_vli_sub(result, result, curve_secp160r1.p, 20);
}
if (carry > 0) {
uECC_vli_sub(result, result, curve_secp160r1.p, 20);
}
if (uECC_vli_cmp_unsafe(result, curve_secp160r1.p, 20) > 0) {
uECC_vli_sub(result, result, curve_secp160r1.p, 20);
}
}
#define asm_mmod_fast_secp160r1 1
#endif /* uECC_SUPPORTS_secp160r1 */
#if uECC_SUPPORTS_secp256k1
static const struct uECC_Curve_t curve_secp256k1;
static void vli_mmod_fast_secp256k1(uECC_word_t *result, uECC_word_t *product) {
uint8_t carry = 0;
__asm__ volatile (
"in r30, __SP_L__ \n\t"
"in r31, __SP_H__ \n\t"
"sbiw r30, 37 \n\t"
"in r0, __SREG__ \n\t"
"cli \n\t"
"out __SP_H__, r31 \n\t"
"out __SREG__, r0 \n\t"
"out __SP_L__, r30 \n\t"
"adiw r30, 1 \n\t" /* add 1 since z initially points below the stack */
"adiw r26, 32 \n\t" /* product + uECC_WORDS */
"ldi r25, 0x03 \n\t"
"ldi r24, 0xD1 \n\t"
"ld r18, x+ \n\t"
"ld r19, x+ \n\t"
"ld r20, x+ \n\t"
"ld r21, x+ \n\t"
"mul r24, r18 \n\t"
"st z+, r0 \n\t"
"mov r22, r1 \n\t"
"ldi r23, 0 \n\t"
"mul r24, r19 \n\t"
"add r22, r0 \n\t"
"adc r23, r1 \n\t" /* can't overflow */
"mul r25, r18 \n\t"
"add r22, r0 \n\t"
"adc r23, r1 \n\t" /* can't overflow */
"st z+, r22 \n\t"
"ldi r22, 0 \n\t"
"mul r24, r20 \n\t"
"add r23, r0 \n\t"
"adc r22, r1 \n\t"
"mul r25, r19 \n\t"
"add r23, r0 \n\t"
"adc r22, r1 \n\t"
"st z+, r23 \n\t"
"ldi r23, 0 \n\t"
"mul r24, r21 \n\t"
"add r22, r0 \n\t"
"adc r23, r1 \n\t"
"mul r25, r20 \n\t"
"add r22, r0 \n\t"
"adc r23, r1 \n\t"
"st z+, r22 \n\t"
"ldi r22, 0 \n\t"
/* now we start adding the 2^32 part as well */
"add r23, r18 \n\t" // 28
"adc r22, r22 \n\t"
"ld r18, x+ \n\t"
"mul r24, r18 \n\t"
"add r23, r0 \n\t"
"adc r22, r1 \n\t"
"mul r25, r21 \n\t"
"add r23, r0 \n\t"
"adc r22, r1 \n\t"
"st z+, r23 \n\t"
"ldi r23, 0 \n\t"
"add r22, r19 \n\t" // 27
"adc r23, r23 \n\t"
"ld r19, x+ \n\t"
"mul r24, r19 \n\t"
"add r22, r0 \n\t"
"adc r23, r1 \n\t"
"mul r25, r18 \n\t"
"add r22, r0 \n\t"
"adc r23, r1 \n\t"
"st z+, r22 \n\t"
"ldi r22, 0 \n\t"
REPEAT(6, // 26 - 3
"add r23, r20 \n\t"
"adc r22, r22 \n\t"
"ld r20, x+ \n\t"
"mul r24, r20 \n\t"
"add r23, r0 \n\t"
"adc r22, r1 \n\t"
"mul r25, r19 \n\t"
"add r23, r0 \n\t"
"adc r22, r1 \n\t"
"st z+, r23 \n\t"
"ldi r23, 0 \n\t"
"add r22, r21 \n\t"
"adc r23, r23 \n\t"
"ld r21, x+ \n\t"
"mul r24, r21 \n\t"
"add r22, r0 \n\t"
"adc r23, r1 \n\t"
"mul r25, r20 \n\t"
"add r22, r0 \n\t"
"adc r23, r1 \n\t"
"st z+, r22 \n\t"
"ldi r22, 0 \n\t"
"add r23, r18 \n\t"
"adc r22, r22 \n\t"
"ld r18, x+ \n\t"
"mul r24, r18 \n\t"
"add r23, r0 \n\t"
"adc r22, r1 \n\t"
"mul r25, r21 \n\t"
"add r23, r0 \n\t"
"adc r22, r1 \n\t"
"st z+, r23 \n\t"
"ldi r23, 0 \n\t"
"add r22, r19 \n\t"
"adc r23, r23 \n\t"
"ld r19, x+ \n\t"
"mul r24, r19 \n\t"
"add r22, r0 \n\t"
"adc r23, r1 \n\t"
"mul r25, r18 \n\t"
"add r22, r0 \n\t"
"adc r23, r1 \n\t"
"st z+, r22 \n\t"
"ldi r22, 0 \n\t")
"add r23, r20 \n\t" // 2
"adc r22, r22 \n\t"
"ld r20, x+ \n\t"
"mul r24, r20 \n\t"
"add r23, r0 \n\t"
"adc r22, r1 \n\t"
"mul r25, r19 \n\t"
"add r23, r0 \n\t"
"adc r22, r1 \n\t"
"st z+, r23 \n\t"
"ldi r23, 0 \n\t"
"add r22, r21 \n\t" // 1
"adc r23, r23 \n\t"
"ld r21, x+ \n\t"
"mul r24, r21 \n\t"
"add r22, r0 \n\t"
"adc r23, r1 \n\t"
"mul r25, r20 \n\t"
"add r22, r0 \n\t"
"adc r23, r1 \n\t"
"st z+, r22 \n\t"
"ldi r22, 0 \n\t"
/* Now finish the carries etc */
"add r23, r18 \n\t"
"adc r22, r22 \n\t"
"mul r25, r21 \n\t"
"add r23, r0 \n\t"
"adc r22, r1 \n\t"
"st z+, r23 \n\t"
"ldi r23, 0 \n\t"
"add r22, r19 \n\t"
"adc r23, r23 \n\t"
"st z+, r22 \n\t"
"ldi r22, 0 \n\t"
"add r23, r20 \n\t"
"adc r22, r22 \n\t"
"st z+, r23 \n\t"
"ldi r23, 0 \n\t"
"add r22, r21 \n\t"
"adc r23, r23 \n\t"
"st z+, r22 \n\t"
"st z+, r23 \n\t"
"eor r1, r1 \n\t" /* make r1 be 0 again */
"sbiw r30, 37 \n\t" /* move z back to point at tmp */
"subi r26, 64 \n\t" /* move x back to point at product */
"sbc r27, __zero_reg__ \n\t"
/* add low bytes of tmp to product, storing in result */
"ld r18, z+ \n\t"
"ld r19, x+ \n\t"
"add r18, r19 \n\t"
"st y+, r18 \n\t"
REPEAT(31,
"ld r18, z+ \n\t"
"ld r19, x+ \n\t"
"adc r18, r19 \n\t"
"st y+, r18 \n\t")
"adc %[carry], __zero_reg__ \n\t" /* Store carry bit (carry flag is cleared). */
/* at this point x is at the end of product, y is at the end of result,
z is 32 bytes into tmp */
"sbiw r28, 32 \n\t" /* move y back to point at result */
/* do omega_mult again with the 5 relevant bytes */
/* z points to tmp + uECC_WORDS, x points to the end of product */
"sbiw r26, 32 \n\t" /* shift x back to point into the product buffer
(we can overwrite it now) */
"ld r18, z+ \n\t"
"ld r19, z+ \n\t"
"ld r20, z+ \n\t"
"ld r21, z+ \n\t"
"mul r24, r18 \n\t"
"st x+, r0 \n\t"
"mov r22, r1 \n\t"
"ldi r23, 0 \n\t"
"mul r24, r19 \n\t"
"add r22, r0 \n\t"
"adc r23, r1 \n\t" /* can't overflow */
"mul r25, r18 \n\t"
"add r22, r0 \n\t"
"adc r23, r1 \n\t" /* can't overflow */
"st x+, r22 \n\t"
"ldi r22, 0 \n\t"
"mul r24, r20 \n\t"
"add r23, r0 \n\t"
"adc r22, r1 \n\t"
"mul r25, r19 \n\t"
"add r23, r0 \n\t"
"adc r22, r1 \n\t"
"st x+, r23 \n\t"
"ldi r23, 0 \n\t"
"mul r24, r21 \n\t"
"add r22, r0 \n\t"
"adc r23, r1 \n\t"
"mul r25, r20 \n\t"
"add r22, r0 \n\t"
"adc r23, r1 \n\t"
"st x+, r22 \n\t"
"ldi r22, 0 \n\t"
"add r23, r18 \n\t"
"adc r22, r22 \n\t"
"ld r18, z+ \n\t"
"mul r24, r18 \n\t"
"add r23, r0 \n\t"
"adc r22, r1 \n\t"
"mul r25, r21 \n\t"
"add r23, r0 \n\t"
"adc r22, r1 \n\t"
"st x+, r23 \n\t"
"ldi r23, 0 \n\t"
/* Now finish the carries etc */
"add r22, r19 \n\t"
"adc r23, r23 \n\t"
"mul r25, r18 \n\t"
"add r22, r0 \n\t"
"adc r23, r1 \n\t"
"st x+, r22 \n\t"
"ldi r22, 0 \n\t"
"add r23, r20 \n\t"
"adc r22, r22 \n\t"
"st x+, r23 \n\t"
"ldi r23, 0 \n\t"
"add r22, r21 \n\t"
"adc r23, r23 \n\t"
"st x+, r22 \n\t"
"ldi r22, 0 \n\t"
"add r23, r18 \n\t"
"adc r22, r22 \n\t"
"st x+, r23 \n\t"
"st x+, r22 \n\t"
"eor r1, r1 \n\t" /* make r1 be 0 again */
/* now z points to the end of tmp, x points to the end of product
(y still points at result) */
"sbiw r26, 10 \n\t" /* move x back to point at beginning of actual data */
/* add into result */
"ld r18, x+ \n\t"
"ld r19, y \n\t"
"add r18, r19 \n\t"
"st y+, r18 \n\t"
REPEAT(9,
"ld r18, x+ \n\t"
"ld r19, y \n\t"
"adc r18, r19 \n\t"
"st y+, r18 \n\t")
/* Done adding, now propagate carry bit */
REPEAT(22,
"ld r18, y \n\t"
"adc r18, __zero_reg__ \n\t"
"st y+, r18 \n\t")
"adc %[carry], __zero_reg__ \n\t" /* Store carry bit (carry flag is cleared). */
"sbiw r28, 32 \n\t" /* move y back to point at result */
"sbiw r30, 1 \n\t" /* fix stack pointer */
"in r0, __SREG__ \n\t"
"cli \n\t"
"out __SP_H__, r31 \n\t"
"out __SREG__, r0 \n\t"
"out __SP_L__, r30 \n\t"
: "+x" (product), [carry] "+r" (carry)
: "y" (result)
: "r0", "r18", "r19", "r20", "r21", "r22", "r23", "r24", "r25", "r30", "r31", "cc"
);
if (carry > 0) {
--carry;
uECC_vli_sub(result, result, curve_secp256k1.p, 32);
}
if (carry > 0) {
uECC_vli_sub(result, result, curve_secp256k1.p, 32);
}
if (uECC_vli_cmp_unsafe(result, curve_secp256k1.p, 32) > 0) {
uECC_vli_sub(result, result, curve_secp256k1.p, 32);
}
}
#define asm_mmod_fast_secp256k1 1
#endif /* uECC_SUPPORTS_secp256k1 */
#endif /* (uECC_OPTIMIZATION_LEVEL >= 2) */
/* ---- "Small" implementations ---- */
#if !asm_add
uECC_VLI_API uECC_word_t uECC_vli_add(uECC_word_t *result,
const uECC_word_t *left,
const uECC_word_t *right,
wordcount_t num_words) {
volatile uECC_word_t *r = result;
uint8_t carry = 0;
uint8_t left_byte;
uint8_t right_byte;
__asm__ volatile (
"clc \n\t"
"1: \n\t"
"ld %[left], x+ \n\t" /* Load left byte. */
"ld %[right], y+ \n\t" /* Load right byte. */
"adc %[left], %[right] \n\t" /* Add. */
"st z+, %[left] \n\t" /* Store the result. */
"dec %[i] \n\t"
"brne 1b \n\t"
"adc %[carry], %[carry] \n\t" /* Store carry bit. */
: "+z" (r), "+x" (left), "+y" (right), [i] "+r" (num_words),
[carry] "+r" (carry), [left] "=&r" (left_byte), [right] "=&r" (right_byte)
:
: "cc"
);
return carry;
}
#define asm_add 1
#endif
#if !asm_sub
uECC_VLI_API uECC_word_t uECC_vli_sub(uECC_word_t *result,
const uECC_word_t *left,
const uECC_word_t *right,
wordcount_t num_words) {
volatile uECC_word_t *r = result;
uint8_t borrow = 0;
uint8_t left_byte;
uint8_t right_byte;
__asm__ volatile (
"clc \n\t"
"1: \n\t"
"ld %[left], x+ \n\t" /* Load left byte. */
"ld %[right], y+ \n\t" /* Load right byte. */
"sbc %[left], %[right] \n\t" /* Subtract. */
"st z+, %[left] \n\t" /* Store the result. */
"dec %[i] \n\t"
"brne 1b \n\t"
"adc %[borrow], %[borrow] \n\t" /* Store carry bit in borrow. */
: "+z" (r), "+x" (left), "+y" (right), [i] "+r" (num_words),
[borrow] "+r" (borrow), [left] "=&r" (left_byte), [right] "=&r" (right_byte)
:
: "cc"
);
return borrow;
}
#define asm_sub 1
#endif
#if !asm_mult
__attribute((noinline))
uECC_VLI_API void uECC_vli_mult(uECC_word_t *result,
const uECC_word_t *left,
const uECC_word_t *right,
wordcount_t num_words) {
volatile uECC_word_t *r = result;
uint8_t r0 = 0;
uint8_t r1 = 0;
uint8_t r2 = 0;
uint8_t zero = 0;
uint8_t k, i;
__asm__ volatile (
"ldi %[k], 1 \n\t" /* k = 1; k < num_words; ++k */
"1: \n\t"
"ldi %[i], 0 \n\t" /* i = 0; i < k; ++i */
"add r28, %[k] \n\t" /* pre-add right ptr */
"adc r29, %[zero] \n\t"
"2: \n\t"
"ld r0, x+ \n\t"
"ld r1, -y \n\t"
"mul r0, r1 \n\t"
"add %[r0], r0 \n\t"
"adc %[r1], r1 \n\t"
"adc %[r2], %[zero] \n\t"
"inc %[i] \n\t"
"cp %[i], %[k] \n\t"
"brlo 2b \n\t" /* loop if i < k */
"sub r26, %[k] \n\t" /* fix up left ptr */
"sbc r27, %[zero] \n\t"
"st z+, %[r0] \n\t" /* Store the result. */
"mov %[r0], %[r1] \n\t"
"mov %[r1], %[r2] \n\t"
"mov %[r2], %[zero] \n\t"
"inc %[k] \n\t"
"cp %[k], %[num] \n\t"
"brlo 1b \n\t" /* loop if k < num_words */
/* second half */
"mov %[k], %[num] \n\t" /* k = num_words; k > 0; --k */
"add r28, %[num] \n\t" /* move right ptr to point at the end of right */
"adc r29, %[zero] \n\t"
"1: \n\t"
"ldi %[i], 0 \n\t" /* i = 0; i < k; ++i */
"2: \n\t"
"ld r0, x+ \n\t"
"ld r1, -y \n\t"
"mul r0, r1 \n\t"
"add %[r0], r0 \n\t"
"adc %[r1], r1 \n\t"
"adc %[r2], %[zero] \n\t"
"inc %[i] \n\t"
"cp %[i], %[k] \n\t"
"brlo 2b \n\t" /* loop if i < k */
"add r28, %[k] \n\t" /* fix up right ptr */
"adc r29, %[zero] \n\t"
"st z+, %[r0] \n\t" /* Store the result. */
"mov %[r0], %[r1] \n\t"
"mov %[r1], %[r2] \n\t"
"mov %[r2], %[zero] \n\t"
"dec %[k] \n\t"
"sub r26, %[k] \n\t" /* fix up left ptr (after k is decremented, so next time
we start 1 higher) */
"sbc r27, %[zero] \n\t"
"cp %[k], %[zero] \n\t"
"brne 1b \n\t" /* loop if k > 0 */
"st z+, %[r0] \n\t" /* Store last result byte. */
"eor r1, r1 \n\t" /* fix r1 to be 0 again */
: "+z" (result), "+x" (left), "+y" (right),
[r0] "+r" (r0), [r1] "+r" (r1), [r2] "+r" (r2),
[zero] "+r" (zero), [num] "+r" (num_words),
[k] "=&r" (k), [i] "=&r" (i)
:
: "r0", "cc"
);
}
#define asm_mult 1
#endif
#if (uECC_SQUARE_FUNC && !asm_square)