about summary refs log tree commit diff stats
path: root/subx/065hex.subx
blob: 374168db276e9d4b49d658ccf14fabb72f92f7fa (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
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
# some utilities for converting numbers to/from hex
# lowercase letters only for now

== code
#   instruction                     effective address                                                   register    displacement    immediate
# . op          subop               mod             rm32          base        index         scale       r32
# . 1-3 bytes   3 bits              2 bits          3 bits        3 bits      3 bits        2 bits      2 bits      0/1/2/4 bytes   0/1/2/4 bytes

is-hex-int?:  # in : (address slice) -> EAX : boolean
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # . save registers
    51/push-ECX
    52/push-EDX
    53/push-EBX
    # ECX = s
    8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .             .           1/r32/ECX   8/disp8         .                 # copy *(EBP+8) to ECX
    # EDX = s->end
    8b/copy                         1/mod/*+disp8   1/rm32/ECX    .           .             .           2/r32/EDX   4/disp8         .                 # copy *(ECX+4) to EDX
    # curr/ECX = s->start
    8b/copy                         0/mod/indirect  1/rm32/ECX    .           .             .           1/r32/ECX   .               .                 # copy *ECX to ECX
    # if s is empty return false
    b8/copy-to-EAX  0/imm32/false
    39/compare                      3/mod/direct    1/rm32/ECX    .           .             .           2/r32/EDX   .               .                 # compare ECX with EDX
    73/jump-if-greater-or-equal-unsigned  $is-hex-int?:end/disp8
    # skip past leading '-'
    # . if (*curr == '-') ++curr
    31/xor                          3/mod/direct    3/rm32/EBX    .           .             .           3/r32/EBX   .               .                 # clear EBX
    8a/copy-byte                    0/mod/indirect  1/rm32/ECX    .           .             .           3/r32/BL    .               .                 # copy byte at *ECX to BL
    81          7/subop/compare     3/mod/direct    3/rm32/EBX    .           .             .           .           .               0x2d/imm32/-      # compare EBX
    75/jump-if-not-equal  $is-hex-int?:initial-0/disp8
    # . ++curr
    41/increment-ECX
    # skip past leading '0x'
$is-hex-int?:initial-0:
    # . if (*curr != '0') jump to loop
    31/xor                          3/mod/direct    3/rm32/EBX    .           .             .           3/r32/EBX   .               .                 # clear EBX
    8a/copy-byte                    0/mod/indirect  1/rm32/ECX    .           .             .           3/r32/BL    .               .                 # copy byte at *ECX to BL
    81          7/subop/compare     3/mod/direct    3/rm32/EBX    .           .             .           .           .               0x30/imm32/0      # compare EBX
    75/jump-if-not-equal  $is-hex-int?:loop/disp8
    # . ++curr
    41/increment-ECX
$is-hex-int?:initial-0x:
    # . if (curr >= in->end) return true
    39/compare                      3/mod/direct    1/rm32/ECX    .           .             .           2/r32/EDX   .               .                 # compare ECX with EDX
    73/jump-if-greater-or-equal-unsigned  $is-hex-int?:true/disp8
    # . if (*curr != 'x') jump to loop  # the previous '0' is still valid so doesn't need to be checked again
    31/xor                          3/mod/direct    3/rm32/EBX    .           .             .           3/r32/EBX   .               .                 # clear EBX
    8a/copy-byte                    0/mod/indirect  1/rm32/ECX    .           .             .           3/r32/BL    .               .                 # copy byte at *ECX to BL
    81          7/subop/compare     3/mod/direct    3/rm32/EBX    .           .             .           .           .               0x78/imm32/x      # compare EBX
    75/jump-if-not-equal  $is-hex-int?:loop/disp8
    # . ++curr
    41/increment-ECX
$is-hex-int?:loop:
    # if (curr >= in->end) return true
    39/compare                      3/mod/direct    1/rm32/ECX    .           .             .           2/r32/EDX   .               .                 # compare ECX with EDX
    73/jump-if-greater-or-equal-unsigned  $is-hex-int?:true/disp8
    # EAX = is-hex-digit?(*curr)
    # . . push args
    8a/copy-byte                    0/mod/indirect  1/rm32/ECX    .           .             .           0/r32/AL    .               .                 # copy byte at *ECX to AL
    50/push-EAX
    # . . call
    e8/call  is-hex-digit?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # if (EAX == false) return false
    3d/compare-EAX-and  0/imm32
    74/jump-if-equal  $is-hex-int?:end/disp8
    # ++curr
    41/increment-ECX
    # loop
    eb/jump  $is-hex-int?:loop/disp8
$is-hex-int?:true:
    # return true
    b8/copy-to-EAX  1/imm32/true
$is-hex-int?:end:
    # . restore registers
    5b/pop-to-EBX
    5a/pop-to-EDX
    59/pop-to-ECX
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-is-hex-int:
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # var slice/ECX = "34"
    68/push  _test-slice-hex-int-end/imm32
    68/push  _test-slice-hex-int/imm32
    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           4/r32/ESP   .               .                 # copy ESP to ECX
    # EAX = is-hex-int?(slice)
    # . . push args
    51/push-ECX
    # . . call
    e8/call  is-hex-int?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 1, msg)
    # . . push args
    68/push  "F - test-is-hex-int"/imm32
    68/push  1/imm32/true
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-is-hex-int-handles-letters:
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # var slice/ECX = "34a"
    68/push  _test-slice-hex-int-letters-end/imm32
    68/push  _test-slice-hex-int-letters/imm32
    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           4/r32/ESP   .               .                 # copy ESP to ECX
    # EAX = is-hex-int?(slice)
    # . . push args
    51/push-ECX
    # . . call
    e8/call  is-hex-int?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 1, msg)
    # . . push args
    68/push  "F - test-is-hex-int-handles-letters"/imm32
    68/push  1/imm32/true
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-is-hex-int-with-trailing-char:
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # var slice/ECX = "34q"
    68/push  _test-slice-digits-and-char-end/imm32
    68/push  _test-slice-digits-and-char/imm32
    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           4/r32/ESP   .               .                 # copy ESP to ECX
    # EAX = is-hex-int?(slice)
    # . . push args
    51/push-ECX
    # . . call
    e8/call  is-hex-int?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 0, msg)
    # . . push args
    68/push  "F - test-is-hex-int-with-trailing-char"/imm32
    68/push  0/imm32/false
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-is-hex-int-with-leading-char:
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # var slice/ECX = "q34"
    68/push  _test-slice-char-and-digits-end/imm32
    68/push  _test-slice-char-and-digits/imm32
    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           4/r32/ESP   .               .                 # copy ESP to ECX
    # EAX = is-hex-int?(slice)
    # . . push args
    51/push-ECX
    # . . call
    e8/call  is-hex-int?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 0, msg)
    # . . push args
    68/push  "F - test-is-hex-int-with-leading-char"/imm32
    68/push  0/imm32/false
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-is-hex-int-empty:
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # var slice/ECX = ""
    68/push  _test-slice-empty-end/imm32
    68/push  _test-slice-empty/imm32
    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           4/r32/ESP   .               .                 # copy ESP to ECX
    # EAX = is-hex-int?(slice)
    # . . push args
    51/push-ECX
    # . . call
    e8/call  is-hex-int?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 0, msg)
    # . . push args
    68/push  "F - test-is-hex-int-empty"/imm32
    68/push  0/imm32/false
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-is-hex-int-handles-0x-prefix:
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # var slice/ECX = "0x3a"
    68/push  _test-slice-hex-int-with-0x-prefix-end/imm32
    68/push  _test-slice-hex-int-with-0x-prefix/imm32
    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           4/r32/ESP   .               .                 # copy ESP to ECX
    # EAX = is-hex-int?(slice)
    # . . push args
    51/push-ECX
    # . . call
    e8/call  is-hex-int?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 1, msg)
    # . . push args
    68/push  "F - test-is-hex-int-handles-0x-prefix"/imm32
    68/push  1/imm32/true
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-is-hex-int-handles-negative:
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # var slice/ECX = "-34a"
    68/push  _test-slice-hex-int-letters-end/imm32
    68/push  _test-slice-hex-int-letters-negative/imm32
    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           4/r32/ESP   .               .                 # copy ESP to ECX
    # EAX = is-hex-int?(slice)
    # . . push args
    51/push-ECX
    # . . call
    e8/call  is-hex-int?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 1, msg)
    # . . push args
    68/push  "F - test-is-hex-int-handles-negative"/imm32
    68/push  1/imm32/true
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-is-hex-int-handles-negative-0x-prefix:
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # var slice/ECX = "-0x3a"
    68/push  _test-slice-hex-int-with-0x-prefix-end/imm32
    68/push  _test-slice-hex-int-with-0x-prefix-negative/imm32
    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           4/r32/ESP   .               .                 # copy ESP to ECX
    # EAX = is-hex-int?(slice)
    # . . push args
    51/push-ECX
    # . . call
    e8/call  is-hex-int?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 1, msg)
    # . . push args
    68/push  "F - test-is-hex-int-handles-negative-0x-prefix"/imm32
    68/push  1/imm32/true
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

parse-hex-int:  # in : (address slice) -> result/EAX
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # . save registers
    51/push-ECX
    52/push-EDX
    53/push-EBX
    56/push-ESI
    # result/EBX = 0
    31/xor                          3/mod/direct    3/rm32/EBX    .           .             .           3/r32/EBX   .               .                 # clear EBX
    # ECX = s
    8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .             .           1/r32/ECX   8/disp8         .                 # copy *(EBP+8) to ECX
    # EDX = s->end
    8b/copy                         1/mod/*+disp8   1/rm32/ECX    .           .             .           2/r32/EDX   4/disp8         .                 # copy *(ECX+4) to EDX
    # curr/ECX = s->start
    8b/copy                         0/mod/indirect  1/rm32/ECX    .           .             .           1/r32/ECX   .               .                 # copy *ECX to ECX
    # negate?/ESI = false
    31/xor                          3/mod/direct    6/rm32/ESI    .           .             .           6/r32/ESI   .               .                 # clear ESI
$parse-hex-int:negative:
    # . if (*curr == '-') negate = true
    31/xor                          3/mod/direct    0/rm32/EAX    .           .             .           0/r32/EAX   .               .                 # clear EAX
    8a/copy-byte                    0/mod/indirect  1/rm32/ECX    .           .             .           0/r32/AL    .               .                 # copy byte at *ECX to AL
    3d/compare-EAX-and  0x2d/imm32/-
    75/jump-if-not-equal  $parse-hex-int:initial-0/disp8
    # . ++curr
    41/increment-ECX
    # . negate = true
    be/copy-to-ESI  1/imm32/true
$parse-hex-int:initial-0:
    # skip past leading '0x'
    # . if (*curr != '0') jump to loop
    8a/copy-byte                    0/mod/indirect  1/rm32/ECX    .           .             .           0/r32/AL    .               .                 # copy byte at *ECX to AL
    3d/compare-EAX-and  0x30/imm32/0
    75/jump-if-not-equal  $parse-hex-int:loop/disp8
    # . ++curr
    41/increment-ECX
$parse-hex-int:initial-0x:
    # . if (curr >= in->end) return result
    39/compare                      3/mod/direct    1/rm32/ECX    .           .             .           2/r32/EDX   .               .                 # compare ECX with EDX
    73/jump-if-greater-or-equal-unsigned  $parse-hex-int:end/disp8
    # . if (*curr != 'x') jump to loop  # the previous '0' is still valid so doesn't need to be checked again
    31/xor                          3/mod/direct    0/rm32/EAX    .           .             .           0/r32/EAX   .               .                 # clear EAX
    8a/copy-byte                    0/mod/indirect  1/rm32/ECX    .           .             .           0/r32/AL    .               .                 # copy byte at *ECX to AL
    3d/compare-EAX-and  0x78/imm32/x
    75/jump-if-not-equal  $parse-hex-int:loop/disp8
    # . ++curr
    41/increment-ECX
$parse-hex-int:loop:
    # if (curr >= in->end) break
    39/compare                      3/mod/direct    1/rm32/ECX    .           .             .           2/r32/EDX   .               .                 # compare ECX with EDX
    73/jump-if-greater-or-equal-unsigned  $parse-hex-int:negate/disp8
    # EAX = from-hex-char(*curr)
    # . . copy arg to EAX
    8a/copy-byte                    0/mod/indirect  1/rm32/ECX    .           .             .           0/r32/AL    .               .                 # copy byte at *ECX to AL
    # . . call
    e8/call  from-hex-char/disp32
    # result = result * 16 + EAX
    c1/shift    4/subop/left        3/mod/direct    3/rm32/EBX    .           .             .           .           .               4/imm8            # shift EBX left by 4 bits
    01/add                          3/mod/direct    3/rm32/EBX    .           .             .           0/r32/EAX   .               .                 # add EAX to EBX
    # ++curr
    41/increment-ECX
    # loop
    eb/jump  $parse-hex-int:loop/disp8
$parse-hex-int:negate:
    81          7/subop/compare     3/mod/direct    6/rm32/ESI    .           .             .           .           .               0/imm32           # compare ESI
    74/jump-if-equal  $parse-hex-int:end/disp8
    f7          3/subop/negate      3/mod/direct    3/rm32/EBX    .           .             .           .           .               .                 # negate EBX
$parse-hex-int:end:
    89/copy                         3/mod/direct    0/rm32/EAX    .           .             .           3/r32/EBX   .               .                 # copy EBX to EAX
    # . restore registers
    5e/pop-to-ESI
    5b/pop-to-EBX
    5a/pop-to-EDX
    59/pop-to-ECX
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-parse-hex-int-single-digit:
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # var slice/ECX = "a"
    68/push  _test-slice-hex-int-single-letter-end/imm32
    68/push  _test-slice-hex-int-single-letter/imm32
    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           4/r32/ESP   .               .                 # copy ESP to ECX
    # EAX = parse-hex-int(slice)
    # . . push args
    51/push-ECX
    # . . call
    e8/call  parse-hex-int/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 0xa, msg)
    # . . push args
    68/push  "F - test-parse-hex-int-single-digit"/imm32
    68/push  0xa/imm32
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-parse-hex-int-multi-digit:
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # var slice/ECX = "34a"
    68/push  _test-slice-hex-int-letters-end/imm32
    68/push  _test-slice-hex-int-letters/imm32
    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           4/r32/ESP   .               .                 # copy ESP to ECX
    # EAX = parse-hex-int(slice)
    # . . push args
    51/push-ECX
    # . . call
    e8/call  parse-hex-int/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 0x34a, msg)
    # . . push args
    68/push  "F - test-parse-hex-int-multi-digit"/imm32
    68/push  0x34a/imm32
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-parse-hex-int-0x-prefix:
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # var slice/ECX = "0x34"
    68/push  _test-slice-hex-int-with-0x-prefix-end/imm32
    68/push  _test-slice-hex-int-with-0x-prefix/imm32
    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           4/r32/ESP   .               .                 # copy ESP to ECX
    # EAX = parse-hex-int(slice)
    # . . push args
    51/push-ECX
    # . . call
    e8/call  parse-hex-int/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 0x34a, msg)
    # . . push args
    68/push  "F - test-parse-hex-int-0x-prefix"/imm32
    68/push  0x34/imm32
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-parse-hex-int-zero:
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # var slice/ECX = "0"
    68/push  _test-slice-hex-int-zero-end/imm32
    68/push  _test-slice-hex-int-zero/imm32
    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           4/r32/ESP   .               .                 # copy ESP to ECX
    # EAX = parse-hex-int(slice)
    # . . push args
    51/push-ECX
    # . . call
    e8/call  parse-hex-int/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 0x34a, msg)
    # . . push args
    68/push  "F - test-parse-hex-int-zero"/imm32
    68/push  0/imm32
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-parse-hex-int-0-prefix:
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # var slice/ECX = "03"
    68/push  _test-slice-hex-int-with-0-prefix-end/imm32
    68/push  _test-slice-hex-int-with-0-prefix/imm32
    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           4/r32/ESP   .               .                 # copy ESP to ECX
    # EAX = parse-hex-int(slice)
    # . . push args
    51/push-ECX
    # . . call
    e8/call  parse-hex-int/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 0x3, msg)
    # . . push args
    68/push  "F - test-parse-hex-int-0-prefix"/imm32
    68/push  0x3/imm32
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-parse-hex-int-negative:
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # var slice/ECX = "-03"
    68/push  _test-slice-hex-int-negative-with-0-prefix-end/imm32
    68/push  _test-slice-hex-int-negative-with-0-prefix/imm32
    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           4/r32/ESP   .               .                 # copy ESP to ECX
    # EAX = parse-hex-int(slice)
    # . . push args
    51/push-ECX
    # . . call
    e8/call  parse-hex-int/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 0xfffffffd, msg)
    # . . push args
    68/push  "F - test-parse-hex-int-negative"/imm32
    68/push  0xfffffffd/imm32
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

is-hex-digit?:  # c : byte -> EAX : boolean
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # . save registers
    51/push-ECX
    # ECX = c
    8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .             .           1/r32/ECX   8/disp8         .                 # copy *(EBP+8) to ECX
    # return false if c < '0'
    b8/copy-to-EAX  0/imm32/false
    81          7/subop/compare     3/mod/direct    1/rm32/ECX    .           .             .           .           .               0x30/imm32        # compare ECX
    7c/jump-if-lesser  $is-hex-digit?:end/disp8
    # return false if c > 'f'
    81          7/subop/compare     3/mod/direct    1/rm32/ECX    .           .             .           .           .               0x66/imm32        # compare ECX
    7f/jump-if-greater  $is-hex-digit?:end/disp8
    # return true if c <= '9'
    b8/copy-to-EAX  1/imm32/true
    81          7/subop/compare     3/mod/direct    1/rm32/ECX    .           .             .           .           .               0x39/imm32        # compare ECX
    7e/jump-if-lesser-or-equal  $is-hex-digit?:end/disp8
    # return true if c >= 'a'
    81          7/subop/compare     3/mod/direct    1/rm32/ECX    .           .             .           .           .               0x61/imm32        # compare ECX
    7d/jump-if-greater-or-equal  $is-hex-digit?:end/disp8
    # otherwise return false
    b8/copy-to-EAX  0/imm32/false
$is-hex-digit?:end:
    # . restore registers
    59/pop-to-ECX
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-hex-below-0:
    # EAX = is-hex-digit?(0x2f)
    # . . push args
    68/push  0x2f/imm32
    # . . call
    e8/call  is-hex-digit?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 0, msg)
    # . . push args
    68/push  "F - test-hex-below-0"/imm32
    68/push  0/imm32/false
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    c3/return

test-hex-0-to-9:
    # EAX = is-hex-digit?(0x30)
    # . . push args
    68/push  0x30/imm32
    # . . call
    e8/call  is-hex-digit?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 1, msg)
    # . . push args
    68/push  "F - test-hex-at-0"/imm32
    68/push  1/imm32/true
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # EAX = is-hex-digit?(0x39)
    # . . push args
    68/push  0x39/imm32
    # . . call
    e8/call  is-hex-digit?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 1, msg)
    # . . push args
    68/push  "F - test-hex-at-9"/imm32
    68/push  1/imm32/true
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    c3/return

test-hex-above-9-to-a:
    # EAX = is-hex-digit?(0x3a)
    # . . push args
    68/push  0x3a/imm32
    # . . call
    e8/call  is-hex-digit?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 0, msg)
    # . . push args
    68/push  "F - test-hex-above-9-to-a"/imm32
    68/push  0/imm32/false
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    c3/return

test-hex-a-to-f:
    # EAX = is-hex-digit?(0x61)
    # . . push args
    68/push  0x61/imm32
    # . . call
    e8/call  is-hex-digit?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 1, msg)
    # . . push args
    68/push  "F - test-hex-at-a"/imm32
    68/push  1/imm32/true
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # EAX = is-hex-digit?(0x66)
    # . . push args
    68/push  0x66/imm32
    # . . call
    e8/call  is-hex-digit?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 1, msg)
    # . . push args
    68/push  "F - test-hex-at-f"/imm32
    68/push  1/imm32/true
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    c3/return

test-hex-above-f:
    # EAX = is-hex-digit?(0x67)
    # . . push args
    68/push  0x67/imm32
    # . . call
    e8/call  is-hex-digit?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 0, msg)
    # . . push args
    68/push  "F - test-hex-above-f"/imm32
    68/push  0/imm32/false
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    c3/return

from-hex-char:  # in/EAX : byte -> out/EAX : nibble
    # no error checking; accepts argument in EAX
    # if (EAX <= '9') return EAX - '0'
    3d/compare-EAX-with  0x39/imm32/9
    7f/jump-if-greater  $from-hex-char:else/disp8
    2d/subtract-from-EAX  0x30/imm32/0
    c3/return
$from-hex-char:else:
    # otherwise return EAX - 'a' + 10
    2d/subtract-from-EAX  0x57/imm32/a-10
    c3/return

to-hex-char:  # in/EAX : nibble -> out/EAX : byte
    # no error checking; accepts argument in EAX
    # if (EAX <= 9) return EAX + '0'
    3d/compare-EAX-with  0x9/imm32/9
    7f/jump-if-greater  $to-hex-char:else/disp8
    05/add-to-EAX  0x30/imm32/0
    c3/return
$to-hex-char:else:
    # otherwise return EAX + 'a' - 10
    05/add-to-EAX  0x57/imm32/a-10
    c3/return

== data

_test-slice-empty:
  # nothing
_test-slice-empty-end:

_test-slice-hex-int:
  33/3 34/4
_test-slice-hex-int-end:

_test-slice-hex-int-letters-negative:
  2d/-
_test-slice-hex-int-letters:
  33/3 34/4 61/a
_test-slice-hex-int-letters-end:

_test-slice-hex-int-single-letter:
  61/a
_test-slice-hex-int-single-letter-end:

_test-slice-char-and-digits:
  71/q 33/3 34/4
_test-slice-char-and-digits-end:

_test-slice-digits-and-char:
  33/3 34/4 71/q
_test-slice-digits-and-char-end:

_test-slice-hex-int-with-0x-prefix-negative:
  2d/-
_test-slice-hex-int-with-0x-prefix:
  30/0 78/x 33/3 34/4
_test-slice-hex-int-with-0x-prefix-end:

_test-slice-hex-int-zero:
  30/0
_test-slice-hex-int-zero-end:

_test-slice-hex-int-with-0-prefix:
  30/0 33/3
_test-slice-hex-int-with-0-prefix-end:

_test-slice-hex-int-negative-with-0-prefix:
  2d/- 30/0 33/3
_test-slice-hex-int-negative-with-0-prefix-end:

# . . vim:nowrap:textwidth=0