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
|
# primitives for emitting traces to a 'trace' stream, and for tests to make assertions on its contents
#
# A trace stream looks like a regular stream:
# write : int # index at which writes go
# read : int # index that we've read until
# data : (array byte) # prefixed by length as usual
# Usually the trace stream will be in a separate segment set aside for the purpose.
#
# primitives for operating on traces (arguments in quotes):
# - initialize-trace-stream: populates Trace-stream with a new segment of the given 'size'
# - trace: adds a 'line' to Trace-stream
# - check-trace-contains: scans from Trace-stream's start for a matching 'line', prints a 'message' to stderr on failure
# - check-trace-scans-to: scans from Trace-stream's read pointer for a matching 'line', prints a 'message' to stderr on failure
== data
# We'll save the address of the trace segment here.
Trace-stream:
0/imm32
Trace-segment:
0/imm32/curr
0/imm32/end
# Fake trace-stream for tests.
# Also illustrates the layout of the real trace-stream (segment).
_test-trace-stream:
# current write index
0/imm32
# current read index
0/imm32
# length
8/imm32
# data
00 00 00 00 00 00 00 00 # 8 bytes
== 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
#? Entry: # run a single test, while debugging
#? e8/call test-trace-single/disp32
#? # syscall(exit, Num-test-failures)
#? 8b/copy 0/mod/indirect 5/rm32/.disp32 . . 3/r32/EBX Num-test-failures/disp32 # copy *Num-test-failures to EBX
#? b8/copy-to-EAX 1/imm32/exit
#? cd/syscall 0x80/imm8
# Allocate a new segment for the trace stream, initialize its length, and save its address to Trace-stream.
# The Trace-stream segment will consist of variable-length lines separated by newlines (0x0a)
initialize-trace-stream: # n : int -> <void>
# . prolog
55/push-EBP
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
# . save registers
50/push-EAX
51/push-ECX
# ECX = n
8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 1/r32/ECX 8/disp8 . # copy *(EBP+8) to ECX
# Trace-segment = new-segment(n)
# . . push args
68/push Trace-segment/imm32
51/push-ECX
# . . call
e8/call new-segment/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# copy Trace-segment->curr to *Trace-stream
8b/copy 0/mod/indirect 5/rm32/.disp32 . . 0/r32/EAX Trace-segment/disp32 # copy *Trace-segment to EAX
89/copy 0/mod/indirect 5/rm32/.disp32 . . 0/r32/EAX Trace-stream/disp32 # copy EAX to *Trace-stream
# Trace-stream->length = n - 12
# . ECX -= 12
81 5/subop/subtract 3/mod/direct 1/rm32/ECX . . . . . 0xc/imm32 # subtract from ECX
# . Trace-stream->length = ECX
89/copy 1/mod/*+disp8 0/rm32/EAX . . . 1/r32/ECX 8/disp8 . # copy ECX to *(EAX+8)
$initialize-trace-stream:end:
# . restore registers
59/pop-to-ECX
58/pop-to-EAX
# . epilog
89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP
5d/pop-to-EBP
c3/return
# Append a string to the given trace stream.
# Silently give up if it's already full. Or truncate the string if there isn't enough room.
trace: # line : string
# . prolog
55/push-EBP
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
# . save registers
50/push-EAX
51/push-ECX
52/push-EDX
53/push-EBX
56/push-ESI
57/push-EDI
# EDI = *Trace-stream
8b/copy 0/mod/indirect 5/rm32/.disp32 . . 7/r32/EDI Trace-stream/disp32 # copy *Trace-stream to EDI
# ESI = line
8b/copy 1/mod/*+disp8 5/rm32/EBP . . 6/r32/ESI 8/disp8 . # copy *(EBP+8) to ESI
# ECX = t->write
8b/copy 0/mod/indirect 7/rm32/EDI . . . 1/r32/ECX . . # copy *EDI to ECX
# EDX = t->length
8b/copy 1/mod/*+disp8 7/rm32/EDI . . . 2/r32/EDX 8/disp8 . # copy *(EDI+8) to EDX
# EAX = _append-3(&t->data[t->write], &t->data[t->length], line)
# . . push line
56/push-ESI
# . . push &t->data[t->length]
8d/copy-address 1/mod/*+disp8 4/rm32/sib 7/base/EDI 2/index/EDX . 3/r32/EBX 0xc/disp8 . # copy EDI+EDX+12 to EBX
53/push-EBX
# . . push &t->data[t->write]
8d/copy-address 1/mod/*+disp8 4/rm32/sib 7/base/EDI 1/index/ECX . 3/r32/EBX 0xc/disp8 . # copy EDI+ECX+12 to EBX
53/push-EBX
# . . call
e8/call _append-3/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP
# if (EAX == 0) return
3d/compare-EAX-and 0/imm32
74/jump-if-equal $trace:end/disp8
# t->write += EAX
01/add 0/mod/indirect 7/rm32/EDI . . . 0/r32/EAX . . # add EAX to *EDI
# refresh ECX = t->write
8b/copy 0/mod/indirect 7/rm32/EDI . . . 1/r32/ECX . . # copy *EDI to ECX
# EAX = _append-3(&t->data[t->write], &t->data[t->length], line)
# . . push line
68/push Newline/imm32
# . . push &t->data[t->length]
8d/copy-address 1/mod/*+disp8 4/rm32/sib 7/base/EDI 2/index/EDX . 3/r32/EBX 0xc/disp8 . # copy EDI+EDX+12 to EBX
53/push-EBX
# . . push &t->data[t->write]
8d/copy-address 1/mod/*+disp8 4/rm32/sib 7/base/EDI 1/index/ECX . 3/r32/EBX 0xc/disp8 . # copy EDI+ECX+12 to EBX
53/push-EBX
# . . call
e8/call _append-3/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP
# t->write += EAX
01/add 0/mod/indirect 7/rm32/EDI . . . 0/r32/EAX . . # add EAX to *EDI
$trace:end:
# . restore registers
5f/pop-to-EDI
5e/pop-to-ESI
5b/pop-to-EBX
5a/pop-to-EDX
59/pop-to-ECX
58/pop-to-EAX
# . epilog
89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP
5d/pop-to-EBP
c3/return
test-trace-single:
# *Trace-stream = _test-trace-stream
b8/copy-to-EAX _test-trace-stream/imm32
89/copy 0/mod/indirect 5/rm32/.disp32 . . 0/r32/EAX Trace-stream/disp32 # copy EAX to *Trace-stream
# clear-trace-stream()
e8/call clear-trace-stream/disp32
# trace("Ab")
# . . push args
68/push "Ab"/imm32
# . . call
e8/call trace/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# check-ints-equal(*_test-trace-stream->data, 41/A 62/b 0a/newline 00, msg)
# . . push args
68/push "F - test-trace-single"/imm32
68/push 0x0a6241/imm32/Ab-newline
# . . push *_test-trace-stream->data
b8/copy-to-EAX _test-trace-stream/imm32
ff 6/subop/push 1/mod/*+disp8 0/rm32/EAX . . . . 0xc/disp8 . # push *(EAX+12)
# . . call
e8/call check-ints-equal/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP
# end
c3/return
test-trace-appends:
# *Trace-stream = _test-trace-stream
b8/copy-to-EAX _test-trace-stream/imm32
89/copy 0/mod/indirect 5/rm32/.disp32 . . 0/r32/EAX Trace-stream/disp32 # copy EAX to *Trace-stream
# clear-trace-stream()
e8/call clear-trace-stream/disp32
# trace("C")
# . . push args
68/push "C"/imm32
# . . call
e8/call trace/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# trace("D")
# . . push args
68/push "D"/imm32
# . . call
e8/call trace/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# check-ints-equal(*_test-trace-stream->data, 43/C 0a/newline 44/D 0a/newline, msg)
# . . push args
68/push "F - test-trace-appends"/imm32
68/push 0x0a440a43/imm32/C-newline-D-newline
# . . push *_test-trace-stream->data
b8/copy-to-EAX _test-trace-stream/imm32
ff 6/subop/push 1/mod/*+disp8 0/rm32/EAX . . . . 0xc/disp8 . # push *(EAX+12)
# . . call
e8/call check-ints-equal/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP
# end
c3/return
test-trace-empty-line:
# *Trace-stream = _test-trace-stream
b8/copy-to-EAX _test-trace-stream/imm32
89/copy 0/mod/indirect 5/rm32/.disp32 . . 0/r32/EAX Trace-stream/disp32 # copy EAX to *Trace-stream
# clear-trace-stream()
e8/call clear-trace-stream/disp32
# trace("")
# . . push args
68/push ""/imm32
# . . call
e8/call trace/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# check-ints-equal(*_test-trace-stream->data, 0, msg)
# . . push args
68/push "F - test-trace-empty-line"/imm32
68/push 0/imm32
# . . push *_test-trace-stream->data
b8/copy-to-EAX _test-trace-stream/imm32
ff 6/subop/push 1/mod/*+disp8 0/rm32/EAX . . . . 0xc/disp8 . # push *(EAX+12)
# . . call
e8/call check-ints-equal/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP
# end
c3/return
check-trace-contains: # line : (address string), msg : (address string)
# . prolog
55/push-EBP
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
# rewind-stream(*Trace-stream)
# . . push args
ff 6/subop/push 0/mod/indirect 5/rm32/.disp32 . . . Trace-stream/disp32 # push *Segment-size
# . . call
e8/call rewind-stream/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# check-trace-can-scan-to(line, msg)
# . . push args
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 8/disp8 . # push *(EBP+8)
# . . call
e8/call check-trace-can-scan-to/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
$check-trace-contains:end:
# . epilog
89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP
5d/pop-to-EBP
c3/return
check-trace-scans-to: # line : (address string), msg : (address string)
# . prolog
55/push-EBP
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
# . save registers
50/push-EAX
# EAX = trace-scan(*Trace-stream, line)
# . . push args
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 8/disp8 . # push *(EBP+8)
ff 6/subop/push 0/mod/indirect 5/rm32/.disp32 . . . Trace-stream/disp32 # push *Segment-size
# . . call
e8/call check-trace-can-scan-to/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# check-ints-equal(EAX, 1, msg)
# . . push args
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
68/push 1/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
$check-trace-scans-to:end:
# . restore registers
58/pop-to-EAX
# . epilog
89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP
5d/pop-to-EBP
c3/return
# Start scanning from Trace-stream->read for 'line'. If found, update Trace-stream->read and return true.
trace-scan: # line : string -> result/EAX : boolean
# pseudocode:
# while true:
# if Trace-stream->read >= Trace-stream->write
# break
# if next-line-matches?(Trace-stream, line)
# skip-next-line(Trace-stream)
# return true
# return false
#
# . prolog
55/push-EBP
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
# . save registers
51/push-ECX
56/push-ESI
# ESI = *Trace-stream
8b/copy 0/mod/indirect 5/rm32/.disp32 . . 6/r32/ESI Trace-stream/disp32 # copy *Trace-stream to ESI
# ECX = Trace-stream->write
$trace-scan:loop:
# if (Trace-stream->read >= Trace-stream->write) return false
39/compare 1/mod/*+disp8 6/rm32/ESI . . . 1/r32/ECX 4/disp8 . # compare ECX with *(ESI+4)
7d/jump-if-greater-or-equal $trace-scan:false/disp8
# EAX = next-line-matches?(Trace-stream, line)
# . . push args
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 8/disp8 . # push *(EBP+8)
56/push-ESI
# . . call
e8/call next-line-matches?/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# if (EAX == 0) continue
3d/compare-EAX-and 0/imm32
74/jump-if-equal $trace-scan:loop/disp8
$trace-scan:true:
# skip-next-line(Trace-stream)
# . . push args
56/push-ESI
# . . call
e8/call skip-next-line/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# return true
b8/copy-to-EAX 1/imm32/true
eb/jump $trace-scan:end/disp8
$trace-scan:false:
b8/copy-to-EAX 0/imm32/false
$trace-scan: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
next-line-matches?: # t : (address stream), line : string -> result/EAX : boolean
# pseudocode:
# while true:
# if (currl >= maxl) break
# if (currt >= maxt) return false
# if (*currt != *currl) return false
# ++currt
# ++currl
# return *currt == '\n'
#
# . prolog
55/push-EBP
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
# . save registers
# ESI = line
# maxl/ECX = line->data + line->size
# currl/ESI = line->data
# EDI = t
# maxt/EDX = t->data + t->write
# currt/EDI = t->data + t->read
$next-line-matches?:loop:
# if (currl >= maxl) break
# if (currt >= maxt) return false
# if (*currt != *currl) return false
# ++currt
# ++currl
$next-line-matches?:break:
# return *currt == '\n'
$next-line-matches?:end:
# . restore registers
# . epilog
89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP
5d/pop-to-EBP
c3/return
skip-next-line: # t : (address stream)
# pseudocode:
# i = t->read
# curr = t->data + t->read
# max = t->data + t->write
# while true
# if (curr >= max) break
# if (*curr == '\n') break
# ++curr
# ++i
# t->read = i
#
# . prolog
55/push-EBP
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
# . save registers
# i = t->read
# curr = t->data + t->read
# max = t->data + t->write
$skip-next-line:loop:
# if (curr >= max) break
# if (*curr == '\n') break
# ++curr
# ++i
$skip-next-line:end:
# t->read = i
# . restore registers
# . epilog
89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP
5d/pop-to-EBP
c3/return
test-trace-scan-first:
# setup
# . *Trace-stream = _test-trace-stream
b8/copy-to-EAX _test-trace-stream/imm32
89/copy 0/mod/indirect 5/rm32/.disp32 . . 0/r32/EAX Trace-stream/disp32 # copy EAX to *Trace-stream
# . clear-trace-stream()
e8/call clear-trace-stream/disp32
# . trace("Ab")
# . . push args
68/push "Ab"/imm32
# . . call
e8/call trace/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# EAX = trace-scan("Ab")
# . . push args
68/push "Ab"/imm32
# . . call
e8/call trace-scan/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-trace-scan-first"/imm32
68/push 1/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
# . end
c3/return
test-trace-scan-skips-lines-until-found:
# setup
# . *Trace-stream = _test-trace-stream
b8/copy-to-EAX _test-trace-stream/imm32
89/copy 0/mod/indirect 5/rm32/.disp32 . . 0/r32/EAX Trace-stream/disp32 # copy EAX to *Trace-stream
# . clear-trace-stream()
e8/call clear-trace-stream/disp32
# . trace("Ab")
# . . push args
68/push "Ab"/imm32
# . . call
e8/call trace/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# . trace("cd")
# . . push args
68/push "cd"/imm32
# . . call
e8/call trace/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# EAX = trace-scan("cd")
# . . push args
68/push "cd"/imm32
# . . call
e8/call trace-scan/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-trace-scan-skips-lines-until-found"/imm32
68/push 1/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
# . end
c3/return
test-trace-second-scan-starts-where-first-left-off:
# setup
# . *Trace-stream = _test-trace-stream
b8/copy-to-EAX _test-trace-stream/imm32
89/copy 0/mod/indirect 5/rm32/.disp32 . . 0/r32/EAX Trace-stream/disp32 # copy EAX to *Trace-stream
# . clear-trace-stream()
e8/call clear-trace-stream/disp32
# . trace("Ab")
# . . push args
68/push "Ab"/imm32
# . . call
e8/call trace/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# . EAX = trace-scan("Ab")
# . . push args
68/push "Ab"/imm32
# . . call
e8/call trace-scan/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# second scan fails
# . EAX = trace-scan("Ab")
# . . push args
68/push "Ab"/imm32
# . . call
e8/call trace-scan/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-trace-second-scan-starts-where-first-left-off"/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
# . end
c3/return
test-trace-scan-failure-leaves-read-index-untouched:
# setup
# . *Trace-stream = _test-trace-stream
b8/copy-to-EAX _test-trace-stream/imm32
89/copy 0/mod/indirect 5/rm32/.disp32 . . 0/r32/EAX Trace-stream/disp32 # copy EAX to *Trace-stream
# . clear-trace-stream()
e8/call clear-trace-stream/disp32
# . trace("Ab")
# . . push args
68/push "Ab"/imm32
# . . call
e8/call trace/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# . check-ints-equal(_test-trace-stream->read, 0, msg)
# . . push args
68/push "F - test-trace-second-scan-starts-where-first-left-off/precondition-failure"/imm32
68/push 0/imm32
b8/copy-to-EAX _test-trace-stream/imm32
ff 6/subop/push 1/mod/*+disp8 0/rm32/EAX . . . . 4/disp8 . # push *(EAX+4)
# . . call
e8/call check-ints-equal/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP
# perform a failing scan
# . EAX = trace-scan("Ax")
# . . push args
68/push "Ax"/imm32
# . . call
e8/call trace-scan/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# no change in read index
# . check-ints-equal(_test-trace-stream->read, 0, msg)
# . . push args
68/push "F - test-trace-second-scan-starts-where-first-left-off"/imm32
68/push 0/imm32
b8/copy-to-EAX _test-trace-stream/imm32
ff 6/subop/push 1/mod/*+disp8 0/rm32/EAX . . . . 4/disp8 . # push *(EAX+4)
# . . call
e8/call check-ints-equal/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP
# . end
c3/return
clear-trace-stream:
# . prolog
55/push-EBP
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
# . save registers
50/push-EAX
51/push-ECX
# EAX = *Trace-stream
8b/copy 0/mod/indirect 5/rm32/.disp32 . . 0/r32/EAX Trace-stream/disp32 # copy *Trace-stream to EAX
# ECX = t->length
8b/copy 1/mod/*+disp8 0/rm32/EAX . . . 1/r32/ECX 8/disp8 . # copy *(EAX+8) to ECX
# ECX = &t->data[t->length]
8d/copy-address 1/mod/*+disp8 4/rm32/sib 0/base/EAX 1/index/ECX . 1/r32/ECX 0xc/disp8 . # copy EAX+ECX+12 to ECX
# t->write = 0
c7 0/subop/copy 0/mod/direct 0/rm32/EAX . . . . . 0/imm32 # copy to *EAX
# t->read = 0
c7 0/subop/copy 1/mod/*+disp8 0/rm32/EAX . . . . 4/disp8 0/imm32 # copy to *(EAX+4)
# EAX = t->data
81 0/subop/add 3/mod/direct 0/rm32/EAX . . . . . 0xc/imm32 # add to EAX
$clear-trace-stream:loop:
# if (EAX >= ECX) break
39/compare 3/mod/direct 0/rm32/EAX . . . 1/r32/ECX . . # compare EAX with ECX
7d/jump-if-greater-or-equal $clear-trace-stream:end/disp8
# *EAX = 0
c7 0/subop/copy 0/mod/direct 0/rm32/EAX . . . . . 0/imm32 # copy to *EAX
# EAX += 4
81 0/subop/add 3/mod/direct 0/rm32/EAX . . . . . 4/imm32 # add to EAX
eb/jump $clear-trace-stream:loop/disp8
$clear-trace-stream:end:
# . restore registers
59/pop-to-ECX
58/pop-to-EAX
# . epilog
89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP
5d/pop-to-EBP
c3/return
# - helpers
# 3-argument variant of _append
_append-3: # out : address, outend : address, s : (array byte) -> num_bytes_appended/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
# EAX = _append-4(out, outend, &s->data[0], &s->data[s->length])
# . . push &s->data[s->length]
8b/copy 1/mod/*+disp8 5/rm32/EBP . . 0/r32/EAX 0x10/disp8 . # copy *(EBP+16) to EAX
8b/copy 0/mod/indirect 0/rm32/EAX . . . 1/r32/ECX . . # copy *EAX to ECX
8d/copy-address 1/mod/*+disp8 4/rm32/sib 0/base/EAX 1/index/ECX . 1/r32/ECX 4/disp8 . # copy EAX+ECX+4 to ECX
51/push-ECX
# . . push &s->data[0]
8d/copy-address 1/mod/*+disp8 0/rm32/EAX . . . 1/r32/ECX 4/disp8 . # copy EAX+4 to ECX
51/push-ECX
# . . push outend
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
# . . push out
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 8/disp8 . # push *(EBP+8)
# . . call
e8/call _append-4/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0x10/imm32 # add to ESP
$_append-3: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
# 4-argument variant of _append
_append-4: # out : address, outend : address, in : address, inend : address -> num_bytes_appended/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
57/push-EDI
# EAX/num_bytes_appended = 0
b8/copy-to-EAX 0/imm32
# EDI = out
8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 7/r32/EDI 8/disp8 . # copy *(EBP+8) to EDI
# EDX = outend
8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 2/r32/EDX 0xc/disp8 . # copy *(EBP+12) to EDX
# ESI = in
8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 6/r32/ESI 0x10/disp8 . # copy *(EBP+16) to ESI
# ECX = inend
8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 1/r32/ECX 0x14/disp8 . # copy *(EBP+20) to ECX
$_append-4:loop:
# if (in >= inend) break
39/compare 3/mod/direct 6/rm32/ESI . . . 1/r32/ECX . . # compare ESI with ECX
7d/jump-if-greater-or-equal $_append-4:end/disp8
# if (out >= outend) abort # just to catch test failures fast
39/compare 3/mod/direct 7/rm32/EDI . . . 2/r32/EDX . . # compare EDI with EDX
7d/jump-if-greater-or-equal $_append-4:abort/disp8
# *out = *in
8a/copy-byte 0/mod/indirect 6/rm32/ESI . . . 3/r32/BL . . # copy byte at *ESI to BL
88/copy-byte 0/mod/indirect 7/rm32/EDI . . . 3/r32/BL . . # copy byte at BL to *EDI
# ++num_bytes_appended
40/increment-EAX
# ++in
46/increment-ESI
# ++out
47/increment-EDI
eb/jump $_append-4:loop/disp8
$_append-4:end:
# . restore registers
5f/pop-to-EDI
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
$_append-4:abort:
# . _write(2/stderr, error)
# . . push args
68/push "stream overflow"/imm32
68/push 2/imm32/stderr
# . . call
e8/call _write/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# . syscall(exit, 1)
bb/copy-to-EBX 1/imm32
b8/copy-to-EAX 1/imm32/exit
cd/syscall 0x80/imm8
# never gets here
# . . vim:nowrap:textwidth=0
|