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
|
# Port of https://github.com/akkartik/crenshaw/blob/master/tutor2.1.pas
# which corresponds to the section "single digits" in https://compilers.iecc.com/crenshaw/tutor2.txt
# except that we support hex digits.
#
# To run (from the subx/ directory):
# $ ./subx translate *.subx apps/crenshaw2-1.subx -o apps/crenshaw2-1
# $ echo '3' |./subx run apps/crenshaw2-1
# Expected output:
# # syscall(exit, 3)
# bb/copy-to-EBX 3/imm32
# b8/copy-to-EAX 1/imm32/exit
# cd/syscall 0x80/imm8
#
# To run the generated output:
# $ echo '3' |./subx run apps/crenshaw2-1 > z1.subx
# $ ./subx translate z1.subx -o z1
# $ ./subx run z1
# $ echo $?
# 3
#
# Stdin must contain just a single hex digit. Other input will print an error:
# $ echo 'xyz' |./subx run apps/crenshaw2-1
# Error: integer expected
#
# Names in this file sometimes follow Crenshaw's original rather than my usual
# naming conventions.
== 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
#? # for debugging: run a single test; don't bother setting status code
#? e8/call test-get-num-reads-single-digit/disp32
#? eb/jump $main:end/disp8
# main: run tests if necessary, call 'compile' if not
# . prolog
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
# - if argc > 1 and argv[1] == "test" then return run_tests()
# . argc > 1
81 7/subop/compare 1/mod/*+disp8 5/rm32/EBP . . . . 0/disp8 1/imm32 # compare *EBP
7e/jump-if-lesser-or-equal $run-main/disp8
# . argv[1] == "test"
# . . push args
68/push "test"/imm32
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 8/disp8 . # push *(EBP+8)
# . . call
e8/call kernel-string-equal/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# . check result
3d/compare-EAX 1/imm32
75/jump-if-not-equal $run-main/disp8
# . run-tests()
e8/call run-tests/disp32
8b/copy 0/mod/indirect 5/rm32/.disp32 . . 3/r32/EBX Num-test-failures/disp32 # copy *Num-test-failures to EBX
eb/jump $main:end/disp8
$run-main:
# - otherwise read a program from stdin and emit its translation to stdout
# var ed/EAX : exit-descriptor
81 5/subop/subtract 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # subtract from ESP
89/copy 3/mod/direct 0/rm32/EAX . . . 4/r32/ESP . . # copy ESP to EAX
# configure ed to really exit()
# . ed->target = 0
c7 0/subop/copy 0/mod/direct 0/rm32/EAX . . . . . 0/imm32 # copy to *EAX
# return compile(Stdin, 1/stdout, 2/stderr, ed)
# . . push args
50/push-EAX/ed
68/push 2/imm32/stderr
68/push 1/imm32/stdout
68/push Stdin/imm32
# . . call
e8/call compile/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0x10/imm32 # add to ESP
# . syscall(exit, 0)
bb/copy-to-EBX 0/imm32
$main:end:
b8/copy-to-EAX 1/imm32/exit
cd/syscall 0x80/imm8
# the main entry point
compile: # in : (address buffered-file), out : fd or (address stream), err : fd or (address stream), ed : (address exit-descriptor) -> <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
# prime the pump
# . Look = get-char(in)
# . . push args
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 8/disp8 . # push *(EBP+8)
# . . call
e8/call get-char/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# var num/ECX : (address stream) on the stack
# Numbers can be 32 bits or 8 hex bytes long. One of them will be in 'Look', so we need space for 7 bytes.
# Sizing the stream just right buys us overflow-handling for free inside 'get-num'.
# Add 12 bytes for 'read', 'write' and 'length' fields, for a total of 19 bytes, or 0x13 in hex.
# The stack pointer is no longer aligned, so dump_stack() can be misleading past this point.
81 5/subop/subtract 3/mod/direct 4/rm32/ESP . . . . . 0x13/imm32 # subtract from ESP
89/copy 3/mod/direct 1/rm32/ECX . . . 4/r32/ESP . . # copy ESP to ECX
# initialize the stream
# . num->length = 7
c7 0/subop/copy 1/mod/*+disp8 1/rm32/ECX . . . . 8/disp8 7/imm32 # copy to *(ECX+8)
# . clear-stream(num)
# . . push args
51/push-ECX
# . . call
e8/call clear-stream/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# read a digit from 'in' into 'num'
# . get-num(in, num, err, ed)
# . . push args
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0x14/disp8 . # push *(EBP+20)
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0x10/disp8 . # push *(EBP+16)
51/push-ECX/num
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 8/disp8 . # push *(EBP+8)
# . . call
e8/call get-num/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0x10/imm32 # add to ESP
# render 'num' into the following template on 'out':
# bb/copy-to-EBX _num_
# b8/copy-to-EAX 1/imm32/exit
# cd/syscall 0x80/imm8
#
# . write(out, "bb/copy-to-EBX ")
# . . push args
68/push "bb/copy-to-EBX "/imm32
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
# . . call
e8/call write/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# . write-stream(out, num)
# . . push args
51/push-ECX/num
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
# . . call
e8/call write-stream/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# . write(out, Newline)
# . . push args
68/push Newline/imm32
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
# . . call
e8/call write/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# . write(out, "b8/copy-to-EAX 1/imm32/exit")
# . . push args
68/push "b8/copy-to-EAX 1/imm32/exit"/imm32
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
# . . call
e8/call write/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# . write(out, Newline)
# . . push args
68/push Newline/imm32
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
# . . call
e8/call write/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# . write(out, "cd/syscall 0x80/imm8")
# . . push args
68/push "cd/syscall 0x80/imm8"/imm32
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
# . . call
e8/call write/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# . write(out, Newline)
# . . push args
68/push Newline/imm32
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
# . . call
e8/call write/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
$compile: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
# Read a single digit into 'out'. Abort if there are none, or if there is no space in 'out'.
# Input comes from the global variable 'Look', and we leave the next byte from
# 'in' into it on exit.
get-num: # in : (address buffered-file), out : (address stream), err : fd or (address stream), ed : (address exit-descriptor) -> <void>
# pseudocode:
# if !is-digit?(Look) expected(ed, err, "integer")
# if out->write >= out->length
# write(err, "Error: too many digits in number\n")
# stop(ed, 1)
# out->data[out->write] = LSB(Look)
# ++out->write
# Look = get-char(in)
#
# registers:
# ESI : in
# EDI : out
# EAX : temp
# ECX : out->write (persisted back at end)
# EDX : out->length
# EBX : temp2
# We can't allocate Look to a register because it gets written implicitly in
# get-char in each iteration of the loop. (Thereby demonstrating that it's
# not the right interface for us. But we'll keep it just to follow Crenshaw.)
#
# . prolog
55/push-EBP
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
# - if is-digit?(Look) expected(ed, err, "integer")
# . EAX = is-digit?(Look)
# . . push args
ff 6/subop/push 0/mod/indirect 5/rm32/.disp32 . . . Look/disp32 . # push *Look
# . . call
e8/call is-digit?/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# . if EAX == 0
3d/compare-EAX 0/imm32
75/jump-if-not-equal $get-num:main/disp8
# . expected(ed, err, "integer")
# . . push args
68/push "integer"/imm32
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0x10/disp8 . # push *(EBP+16)
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0x14/disp8 . # push *(EBP+20)
# . . call
e8/call expected/disp32 # never returns
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP
$get-num:main:
# - otherwise read a digit
# . save registers
50/push-EAX
51/push-ECX
52/push-EDX
53/push-EBX
56/push-ESI
57/push-EDI
# read necessary variables to registers
# ESI = in
8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 6/r32/ESI 8/disp8 . # copy *(EBP+8) to ESI
# EDI = out
8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 7/r32/EDI 0xc/disp8 . # copy *(EBP+12) to EDI
# ECX = out->write
8b/copy 0/mod/indirect 7/rm32/EDI . . . 1/r32/ECX . . # copy *EDI to ECX
# EDX = out->length
8b/copy 1/mod/*+disp8 7/rm32/EDI . . . 2/r32/EDX 8/disp8 . # copy *(EDI+8) to EDX
# if out->write >= out->length error
39/compare 3/mod/direct 2/rm32/EDX . . . 1/r32/ECX . . # compare EDX with ECX
7d/jump-if-lesser $get-num:stage2/disp8
# . error(ed, err, msg) # TODO: show full number
# . . push args
68/push "get-num: too many digits in number"/imm32
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0x10/disp8 . # push *(EBP+16)
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0x14/disp8 . # push *(EBP+20)
# . . call
e8/call error/disp32 # never returns
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP
$get-num:stage2:
# out->data[out->write] = LSB(Look)
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
8b/copy 0/mod/indirect 5/rm32/.disp32 . . 0/r32/EAX Look/disp32 . # copy *Look to EAX
88/copy-byte 0/mod/indirect 3/rm32/EBX . . . 0/r32/AL . . # copy byte at AL to *EBX
# ++out->write
41/increment-ECX
# Look = get-char(in)
# . . push args
56/push-ESI
# . . call
e8/call get-char/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
$get-num:loop-end:
# persist necessary variables from registers
89/copy 0/mod/indirect 7/rm32/EDI . . . 1/r32/ECX . . # copy ECX to *EDI
$get-num: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-get-num-reads-single-digit:
# - check that get-num returns first character if it's a digit
# This test uses exit-descriptors. Use EBP for setting up local variables.
55/push-EBP
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
# clear all streams
# . clear-stream(_test-stream)
# . . push args
68/push _test-stream/imm32
# . . call
e8/call clear-stream/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# . clear-stream(_test-buffered-file+4)
# . . push args
b8/copy-to-EAX _test-buffered-file/imm32
05/add-to-EAX 4/imm32
50/push-EAX
# . . call
e8/call clear-stream/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# . clear-stream(_test-output-stream)
# . . push args
68/push _test-output-stream/imm32
# . . call
e8/call clear-stream/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# . clear-stream(_test-error-stream)
# . . push args
68/push _test-error-stream/imm32
# . . call
e8/call clear-stream/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# initialize 'in'
# . write(_test-stream, "3")
# . . push args
68/push "3"/imm32
68/push _test-stream/imm32
# . . call
e8/call write/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# initialize exit-descriptor 'ed' for the call to 'get-num' below
# . var ed/EAX : exit-descriptor
81 5/subop/subtract 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # subtract from ESP
89/copy 3/mod/direct 0/rm32/EAX . . . 4/r32/ESP . . # copy ESP to EAX
# . tailor-exit-descriptor(ed, 16)
# . . push args
68/push 0x10/imm32/nbytes-of-args-for-get-num
50/push-EAX/ed
# . . call
e8/call tailor-exit-descriptor/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# prime the pump
# . get-char(_test-buffered-file)
# . . push args
68/push _test-buffered-file/imm32
# . . call
e8/call get-char/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# get-num(in, out, err, ed)
# . . push args
50/push-EAX/ed
68/push _test-error-stream/imm32
68/push _test-output-stream/imm32
68/push _test-buffered-file/imm32
# . . call
e8/call get-num/disp32
# registers except ESP may be clobbered at this point
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0x10/imm32 # add to ESP
# check-ints-equal(*_test-output-stream->data, '3', msg)
# . . push args
68/push "F - test-get-num-reads-single-digit"/imm32
68/push 0x33/imm32
b8/copy-to-EAX _test-output-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
# . reclaim locals
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
5d/pop-to-EBP
c3/return
test-get-num-aborts-on-non-digit-in-Look:
# - check that get-num returns first character if it's a digit
# This test uses exit-descriptors. Use EBP for setting up local variables.
55/push-EBP
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
# clear all streams
# . clear-stream(_test-stream)
# . . push args
68/push _test-stream/imm32
# . . call
e8/call clear-stream/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# . clear-stream(_test-buffered-file+4)
# . . push args
b8/copy-to-EAX _test-buffered-file/imm32
05/add-to-EAX 4/imm32
50/push-EAX
# . . call
e8/call clear-stream/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# . clear-stream(_test-output-stream)
# . . push args
68/push _test-output-stream/imm32
# . . call
e8/call clear-stream/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# . clear-stream(_test-error-stream)
# . . push args
68/push _test-error-stream/imm32
# . . call
e8/call clear-stream/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# initialize 'in'
# . write(_test-stream, "3")
# . . push args
68/push "3"/imm32
68/push _test-stream/imm32
# . . call
e8/call write/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# initialize exit-descriptor 'ed' for the call to 'get-num' below
# . var ed/EAX : (address exit-descriptor)
81 5/subop/subtract 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # subtract from ESP
89/copy 3/mod/direct 0/rm32/EAX . . . 4/r32/ESP . . # copy ESP to EAX
# . tailor-exit-descriptor(ed, 16)
# . . push args
68/push 0x10/imm32/nbytes-of-args-for-get-num
50/push-EAX/ed
# . . call
e8/call tailor-exit-descriptor/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# *don't* prime the pump
# get-num(in, out, err, ed)
# . . push args
50/push-EAX/ed
68/push _test-error-stream/imm32
68/push _test-output-stream/imm32
68/push _test-buffered-file/imm32
# . . call
e8/call get-num/disp32
# registers except ESP may be clobbered at this point
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0x10/imm32 # add to ESP
# check that get-num tried to call exit(1)
# . check-ints-equal(ed->value, 2, msg) # i.e. stop was called with value 1
# . . push args
68/push "F - test-get-num-aborts-on-non-digit-in-Look"/imm32
68/push 2/imm32
# . . push ed->value
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
# . reclaim locals
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
5d/pop-to-EBP
c3/return
## helpers
# write(f, "Error: "+s+" expected\n") then stop(ed, 1)
expected: # ed : (address exit-descriptor), f : fd or (address stream), s : (address array byte) -> <void>
# . prolog
55/push-EBP
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
# write(f, "Error: ")
# . . push args
68/push "Error: "/imm32
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
# . . call
e8/call write/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# write(f, s)
# . . push args
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0x10/disp8 . # push *(EBP+16)
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
# . . call
e8/call write/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# write(f, " expected")
# . . push args
68/push " expected"/imm32
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
# . . call
e8/call write/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# write(f, Newline)
# . . push args
68/push Newline/imm32
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
# . . call
e8/call write/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# stop(ed, 1)
# . . push args
68/push 1/imm32
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 8/disp8 . # push *(EBP+8)
# . . call
e8/call stop/disp32
# should never get past this point
$expected:dead-end:
# . epilog
89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP
5d/pop-to-EBP
c3/return
# read a byte from 'f', and save it in 'Look'
get-char: # f : (address buffered-file) -> <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
# read-byte(f)
# . . push args
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 8/disp8 . # push *(EBP+8)
# . . call
e8/call read-byte/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# save EAX to Look
89/copy 0/mod/indirect 5/rm32/.disp32 . . 0/r32/EAX Look/disp32 . # copy EAX to *Look
$get-char: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
is-digit?: # c : int -> bool/EAX
# . prolog
55/push-EBP
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
# EAX = false
b8/copy-to-EAX 0/imm32
# if c < '0' return false
81 7/subop/compare 1/mod/*+disp8 5/rm32/EBP . . . . 8/disp8 0x30/imm32 # compare *(EBP+8)
7c/jump-if-lesser $is-digit?:end/disp8
# if c > '9' return false
81 7/subop/compare 1/mod/*+disp8 5/rm32/EBP . . . . 8/disp8 0x39/imm32 # compare *(EBP+8)
7f/jump-if-greater $is-digit?:end/disp8
# otherwise return true
b8/copy-to-EAX 1/imm32
$is-digit?:end:
# . epilog
89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP
5d/pop-to-EBP
c3/return
== data
Look: # (char)
00 00 00 00 # = 0
_test-output-stream:
# current write index
00 00 00 00
# current read index
00 00 00 00
# length (= 8)
08 00 00 00
# data
00 00 00 00 00 00 00 00 # 8 bytes
_test-error-stream:
# current write index
00 00 00 00
# current read index
00 00 00 00
# length (= 8)
08 00 00 00
# data
00 00 00 00 00 00 00 00 # 8 bytes
# . . vim:nowrap:textwidth=0
|