about summary refs log blame commit diff stats
path: root/factorial.mu
blob: 96a28fd3e6da197438589eaa95ecdfbfde5900a2 (plain) (tree)
1
2
3
4
5
6
7
8
9
                     
                                                               
                           
         
                     


                                                
   
                           



                                                          
  
 
                
                                    
                                 
                                                
                           
  
(function factorial [
  (default-space:space-address <- new space:literal 30:literal)
  (n:integer <- next-input)
  { begin
    ; if n=0 return 1
    (zero?:boolean <- equal n:integer 0:literal)
    (break-unless zero?:boolean)
    (reply 1:literal)
  }
  ; return n*factorial(n-1)
  (x:integer <- subtract n:integer 1:literal)
  (subresult:integer <- factorial x:integer)
  (result:integer <- multiply subresult:integer n:integer)
  (reply result:integer)
])

(function main [
  (1:integer <- factorial 5:literal)
  ($print (("result: " literal)))
  (print-integer nil:literal/terminal 1:integer)
  ($print (("\n" literal)))
])
le='Blame the previous revision' href='/akkartik/mu/blame/subx/055trace.subx?h=hlt&id=e9661581f092f3e210b7bd900af058d8b8c4369e'>^
35dd69f7 ^

6030d7e2 ^
35dd69f7 ^
6030d7e2 ^




9d27e966 ^
6030d7e2 ^
9d27e966 ^
6030d7e2 ^

9d27e966 ^
6030d7e2 ^

ee9a9237 ^
6030d7e2 ^
ee9a9237 ^
6030d7e2 ^
1639687b ^
615a7e95 ^
6030d7e2 ^





9d27e966 ^
6030d7e2 ^
9d27e966 ^
6030d7e2 ^

9d27e966 ^
6030d7e2 ^

ee9a9237 ^
6030d7e2 ^
ee9a9237 ^
6030d7e2 ^


33ad0851 ^
ee9a9237 ^
6030d7e2 ^





ee9a9237 ^
6030d7e2 ^


33ad0851 ^
a0467aa2 ^
120a7408 ^

35dd69f7 ^



6030d7e2 ^
35dd69f7 ^
ee9a9237 ^
6030d7e2 ^
ee9a9237 ^
6030d7e2 ^
ee9a9237 ^
35dd69f7 ^
c98d4b1c ^
ee9a9237 ^
6030d7e2 ^

c98d4b1c ^
6030d7e2 ^

ee9a9237 ^
6030d7e2 ^
ee9a9237 ^
6030d7e2 ^
120a7408 ^
551112ff ^
6030d7e2 ^

33ad0851 ^
a0467aa2 ^
120a7408 ^

35dd69f7 ^



6030d7e2 ^
35dd69f7 ^
ee9a9237 ^
6030d7e2 ^
ee9a9237 ^
6030d7e2 ^
ee9a9237 ^
35dd69f7 ^

ee9a9237 ^
6030d7e2 ^
ee9a9237 ^
6030d7e2 ^
ee9a9237 ^
35dd69f7 ^
c98d4b1c ^
ee9a9237 ^
6030d7e2 ^

c98d4b1c ^
6030d7e2 ^

ee9a9237 ^
6030d7e2 ^
ee9a9237 ^
6030d7e2 ^
120a7408 ^
551112ff ^
6030d7e2 ^

a0467aa2 ^
7c397786 ^
120a7408 ^

35dd69f7 ^



6030d7e2 ^
35dd69f7 ^
ee9a9237 ^
6030d7e2 ^
ee9a9237 ^
6030d7e2 ^
ee9a9237 ^
35dd69f7 ^
c98d4b1c ^
ee9a9237 ^
6030d7e2 ^

c98d4b1c ^
6030d7e2 ^

ee9a9237 ^
6030d7e2 ^
ee9a9237 ^
6030d7e2 ^
120a7408 ^
551112ff ^
6030d7e2 ^

7c397786 ^
c437318d ^





89a7cac6 ^
c437318d ^



28795052 ^
c437318d ^



28795052 ^
c437318d ^













51c311d5 ^
c437318d ^

c437318d ^
28795052 ^
c437318d ^
51c311d5 ^
c437318d ^

















b41c2c71 ^
c437318d ^
21299a30 ^
c437318d ^




21299a30 ^
c437318d ^
21299a30 ^

c437318d ^










e9860d21 ^
21299a30 ^

c437318d ^













21299a30 ^
c437318d ^







21299a30 ^

c437318d ^


21299a30 ^








c437318d ^
21299a30 ^


c437318d ^








3b2d621b ^
120a7408 ^

3b2d621b ^




























120a7408 ^
551112ff ^
3b2d621b ^



120a7408 ^

3b2d621b ^



































120a7408 ^
551112ff ^
3b2d621b ^



120a7408 ^

3b2d621b ^




































120a7408 ^
551112ff ^
3b2d621b ^



120a7408 ^

3b2d621b ^









































120a7408 ^
551112ff ^
3b2d621b ^


b41c2c71 ^
c437318d ^












1efabd28 ^






c437318d ^
1efabd28 ^






c437318d ^
1efabd28 ^


c437318d ^
1efabd28 ^



c437318d ^
1efabd28 ^



c437318d ^
1efabd28 ^

51c311d5 ^
1efabd28 ^



51c311d5 ^
1efabd28 ^
















c437318d ^

1efabd28 ^







c437318d ^

1efabd28 ^




c437318d ^




5be5fcd7 ^



1efabd28 ^
8effbb47 ^
5be5fcd7 ^
1efabd28 ^
5be5fcd7 ^
1efabd28 ^
5be5fcd7 ^


1efabd28 ^

5be5fcd7 ^
1efabd28 ^
5be5fcd7 ^
1efabd28 ^
5be5fcd7 ^





1efabd28 ^
8effbb47 ^
5be5fcd7 ^
1efabd28 ^
5be5fcd7 ^
1efabd28 ^
5be5fcd7 ^


1efabd28 ^

5be5fcd7 ^
1efabd28 ^
5be5fcd7 ^
1efabd28 ^
5be5fcd7 ^





1efabd28 ^
8effbb47 ^
5be5fcd7 ^
1efabd28 ^
5be5fcd7 ^
1efabd28 ^
5be5fcd7 ^


1efabd28 ^

5be5fcd7 ^
1efabd28 ^
5be5fcd7 ^
1efabd28 ^
5be5fcd7 ^





1efabd28 ^
8effbb47 ^
5be5fcd7 ^
1efabd28 ^
5be5fcd7 ^
1efabd28 ^
5be5fcd7 ^


1efabd28 ^

5be5fcd7 ^
1efabd28 ^
5be5fcd7 ^
1efabd28 ^


21299a30 ^
c437318d ^

fbb92d80 ^
c437318d ^

c437318d ^

21299a30 ^
c437318d ^

c437318d ^





fbb92d80 ^

















c437318d ^
fbb92d80 ^

51c311d5 ^
21299a30 ^

fbb92d80 ^
07ef0715 ^

fbb92d80 ^



fbb92d80 ^

c437318d ^
fbb92d80 ^



c437318d ^
fbb92d80 ^



c437318d ^




5be5fcd7 ^



ff30b00b ^
5be5fcd7 ^
fbb92d80 ^
5be5fcd7 ^
fbb92d80 ^
5be5fcd7 ^



ff30b00b ^
fbb92d80 ^
fbb92d80 ^
5be5fcd7 ^
fbb92d80 ^
5be5fcd7 ^
fbb92d80 ^
5be5fcd7 ^





ff30b00b ^
5be5fcd7 ^
fbb92d80 ^
5be5fcd7 ^
fbb92d80 ^
5be5fcd7 ^



ff30b00b ^
fbb92d80 ^
fbb92d80 ^
5be5fcd7 ^
fbb92d80 ^
5be5fcd7 ^
fbb92d80 ^


35dd69f7 ^





















51c311d5 ^
35dd69f7 ^













9d27e966 ^
b3d8c144 ^


ee9a9237 ^
6030d7e2 ^

ee9a9237 ^
6030d7e2 ^
52a2a21c ^
c98d4b1c ^
dd9ba09a ^
6030d7e2 ^
6030d7e2 ^

c98d4b1c ^
6030d7e2 ^

9d27e966 ^
dd9ba09a ^
9d27e966 ^
dd9ba09a ^
ee9a9237 ^
6030d7e2 ^
ee9a9237 ^
6030d7e2 ^
cf02c20b ^
ee9a9237 ^
6030d7e2 ^
ee9a9237 ^
6030d7e2 ^


8b0e960d ^


ee9a9237 ^
6030d7e2 ^

ee9a9237 ^
6030d7e2 ^







dd9ba09a ^
6030d7e2 ^
dd9ba09a ^
6030d7e2 ^
dd9ba09a ^
6030d7e2 ^
dd9ba09a ^
8b0e960d ^
1639687b ^
6030d7e2 ^
51c311d5 ^
52a2a21c ^
6030d7e2 ^
51c311d5 ^
1639687b ^
6030d7e2 ^

1639687b ^
6030d7e2 ^
1639687b ^
6030d7e2 ^
1639687b ^
6030d7e2 ^

8b0e960d ^
ee9a9237 ^
6030d7e2 ^




ee9a9237 ^
6030d7e2 ^


b3d8c144 ^
52a2a21c ^


3a044623 ^
52a2a21c ^










8effbb47 ^


f3d3c4ec ^
8effbb47 ^
f3d3c4ec ^
8effbb47 ^





ff30b00b ^
f3d3c4ec ^
8effbb47 ^
f3d3c4ec ^
8effbb47 ^



ff30b00b ^


f3d3c4ec ^
ff30b00b ^
f3d3c4ec ^
ff30b00b ^



8effbb47 ^

ee9a9237 ^
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
                                                                                                      
 
                                             
                                           
                                             
                                                      
                                                                                   
 




                                                                                                                                 




                                                   
           
 

                
                 
 

                                                                 
                   
                         
           
                        


            

                                      

       


                                                                                                                                                 
 

                                                                                                           








                                                                                                                                                                            
                                    
                   
                                
               
              
                               
                      


                                                                                                                                                                                  

                                             
                                                                                                                                                                                 











                                                                                                                                                                            
             
 

                                                                                           
                                 
              

                                                                                                                                                                       
                      





               

                                                                                                                                                                                 
                
                                                                                                                                                                            




                                                                                                                                                                            
                   
               
                                  

                                                                                                                                                                              
                                 

                                                                                                                                                                              
              
                             
                      
                                                                                                                                                                  
                          
                               





                                                                                                                                                                        
                   
                          
                                  

                                                                                                                                                                              
                                 

                                                                                                                                                                              
              
                             
                      


                                                                                                                                                                       
           
                         





                 
              


                                                                                                                                                                       
 
                  

                                                                                                                                                                          



                                                                                                                                                                                 
                                      
                 
                   
                       
              
                         
                      
                                                                                                                                                                  
                                                                               
                   

                                          
                                        

                                                                                                                                                                      
              
                                    
                      
                                                                                                                                                                  
                            
                                                                                                                                                                              

             
 
                   

                                                                                                                                                                          



                                                                                                                                                                                 
                                      
                
                   
                      
              
                         
                      

                                                                                                                                                                  
                   
                      
              
                         
                      
                                                                                                                                                                  
                                                                                       
                   

                                                 
                                        

                                                                                                                                                                      
              
                                    
                      
                                                                                                                                                                  
                            
                                                                                                                                                                              

             
 
                      

                                                                                                                                                                          



                                                                                                                                                                                 
                                      
               
                   
                     
              
                         
                      
                                                                                                                                                                  
                                                         
                   

                                              
                                        

                                                                                                                                                                      
              
                                    
                      
                                                                                                                                                                  
                            
                                                                                                                                                                              

             
 





                                                                                                                                                                       
                                                                                                                                                                          



                                                                                                                                                                  
                                     



                                                                                                                                                                      
                                        













                                                                                                                                                                       
                            

                                                                                                                                                                     
              
                              
                      
                                                                                                                                                                  

















                                                                                                                                                                       
                                                              
                 
                               




                                                      
                                                 
                       

                                            










                                                                                                                                                                                 
                                                                                                                                                                        

                                                                                                                                                                     













                                                                                                                                                                                 
                                                







                                                                                                                                                                  

                                                                                                                                                                  


                                  








                                                                                                                                                                  
                  


                                                                                                                                                                       








                                                                                                                                                                       
                      

                                                                                                                                                                          




























                                                                                                                                                                                 
                            
                                                                                                                                                                              



                                        

                                                                                                                                                                          



































                                                                                                                                                                                 
                            
                                                                                                                                                                              



                                                   

                                                                                                                                                                          




































                                                                                                                                                                                 
                            
                                                                                                                                                                              



                                                    

                                                                                                                                                                          









































                                                                                                                                                                                 
                            
                                                                                                                                                                              


             
                                                                                            












                                                                                                                                                                       






                                                                                                                                                                             
                            






                                                                                                                                                                           
             


                                                                                                                                                                            
                                   



                                                                                                                                                                           
                                   



                                                                                                                                                                            
                         

                                                                                                                                                                           
                                                                         



                                                                                                                                                                           
                                                                       
















                                                                                                                                                                           

                           







                                                                                                                                                                        

                         




                 




                                                                                                                                                                       



                                                                      
                              
                                          
              
                                      
                      
                                                                                                                                                                  


                                                           

                    
              
                                    
                      
                                                                                                                                                                  





                                                             
                     
                                          
              
                                      
                      
                                                                                                                                                                  


                                                           

                    
              
                                    
                      
                                                                                                                                                                  





                                                               
                       
                                          
              
                                      
                      
                                                                                                                                                                  


                                                           

                    
              
                                    
                      
                                                                                                                                                                  





                                                                  
                          
                                          
              
                                      
                      
                                                                                                                                                                  


                                                      

                    
              
                                    
                      


                                                                                                                                                                  
                                      

                                       
                                

                                

                                
             

                                  





                                                                                                                                                                       

















                                                                                                                                                                            
                     

                                                                                                                                                                           
                                                                   

                    
                                  

                                                                                                                                                                        



                                               

                                       
                    



                                                                                                                                                                            
                         



                 




                                                                                                                                                                       



                                                                 
                                     
              
                                  
                      
                                                                                                                                                                  



                                                          
                                            
                                                                                                                                                                            
               
              
                                    
                      
                                                                                                                                                                  





                                                                                    
                                      
              
                                  
                      
                                                                                                                                                                  



                                                           
                                             
                                                                                                                                                                            
               
              
                                    
                      


                                                                                                                                                                  





















                                                                                                                                                                                 
                                                                       













                                                                                                                                                                       
           


                                                                                         
              

                                                                                                                                                                       
                      
               
                                                                    
                                  
                                                                                                                                                                             
                                                                                                                                                                        

                                                                                                                                                                             
                          

                                                                                                                                                                         
                     
                                                                                                                                                                      
                  
                                                                                                                                                                     
              
                             
                      
                                                                                                                                                                  
               
                         
                 
              


                                                                                                                                                                       


                                                                                                      
              

                                                                                                                                                                       
                      







                                
                                                                                                                                                                            
                  
                                                                                                                                                                             
              
                                                                                                                                                                             
                 
                                                                                                                                                                             
                
                            
                                                                                                                                                                            
                                                              
                                                                  
                                                                                                                                                                            
                                                                
                

                                                                                                                                                                               
                          
                    
          
                    
           

                                  
               
                         




                 
              


                                                                                                                                                                       
 


                               
                                      










                                                                                                                                                                  


                        
           
           
          





                                      
                   
           
           
          



            


                                      
           
           
          



            

                                      
                            
# 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/limit

# 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

# 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
    # watch point to catch Trace-stream leaks
#? $watch-1:
    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 : (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
    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:
    # push *Trace-stream
    ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
    # *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
    # pop into *Trace-stream
    8f          0/subop/pop         0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # pop into *Trace-stream
    # end
    c3/return

test-trace-appends:
    # push *Trace-stream
    ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
    # *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
    # pop into *Trace-stream
    8f          0/subop/pop         0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # pop into *Trace-stream
    # end
    c3/return

test-trace-empty-line:
    # push *Trace-stream
    ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
    # *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
    # pop into *Trace-stream
    8f          0/subop/pop         0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # pop into *Trace-stream
    # 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 *Trace-stream
    # . . 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-scans-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-scans-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(line)
    # . . push args
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
    # . . 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
    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 : (address string) -> result/EAX : boolean
    # pseudocode:
    #   push Trace-stream->read
    #   while true:
    #     if Trace-stream->read >= Trace-stream->write
    #       break
    #     if next-line-matches?(Trace-stream, line)
    #       skip-next-line(Trace-stream)
    #       dump saved copy of Trace-stream->read
    #       return true
    #     skip-next-line(Trace-stream)
    #   pop saved copy of Trace-stream->read
    #   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
    8b/copy                         0/mod/indirect  6/rm32/ESI    .           .             .           1/r32/ECX                   .                 # copy *ESI to ECX
    # push Trace-stream->read
    ff          6/subop/push        1/mod/*+disp8   6/rm32/ESI    .           .             .           .           4/disp8         .                 # push *(ESI+4)
$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:continue/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
    # dump saved copy of Trace-stream->read
    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:continue:
    # 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
    eb/jump  $trace-scan:loop/disp8
$trace-scan:false:
    # restore saved copy of Trace-stream->read
    8f          0/subop/pop         1/mod/*+disp8   6/rm32/ESI    .           .             .           .           4/disp8         .                 # pop to *(ESI+4)
    # return 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

test-trace-scan-first:
    # push *Trace-stream
    ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
    # 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
    # pop into *Trace-stream
    8f          0/subop/pop         0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # pop into *Trace-stream
    # . end
    c3/return

test-trace-scan-skips-lines-until-found:
    # push *Trace-stream
    ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
    # 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
    # pop into *Trace-stream
    8f          0/subop/pop         0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # pop into *Trace-stream
    # . end
    c3/return

test-trace-second-scan-starts-where-first-left-off:
    # push *Trace-stream
    ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
    # 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
    # pop into *Trace-stream
    8f          0/subop/pop         0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # pop into *Trace-stream
    # . end
    c3/return

test-trace-scan-failure-leaves-read-index-untouched:
    # push *Trace-stream
    ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
    # 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
    # pop into *Trace-stream
    8f          0/subop/pop         0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # pop into *Trace-stream
    # . end
    c3/return

next-line-matches?:  # t : (address stream), line : (address 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
    51/push-ECX
    52/push-EDX
    53/push-EBX
    56/push-ESI
    57/push-EDI
    # EDX = line
    8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .                         2/r32/EDX   0xc/disp8       .                 # copy *(EBP+12) to EDX
    # currl/ESI = line->data
    # . ESI = line/EDX->data
    8d/copy-address                 1/mod/*+disp8   2/rm32/EDX    .           .             .           6/r32/ESI   4/disp8         .                 # copy EDX+4 to ESI
    # maxl/ECX = line->data + line->size
    # . EAX = line/EDX->size
    8b/copy                         0/mod/indirect  2/rm32/EDX    .           .                         0/r32/EAX   .               .                 # copy *EDX to EAX
    # . maxl/ECX = line->data/ESI + line->size/EAX
    8d/copy-address                 0/mod/indirect  4/rm32/sib    6/base/ESI  0/index/EAX   .           1/r32/ECX   .               .                 # copy EDX+EAX to ECX
    # EDI = t
    8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .                         7/r32/EDI   8/disp8         .                 # copy *(EBP+8) to EDI
    # EBX = t->data
    8d/copy-address                 1/mod/*+disp8   7/rm32/EDI    .           .             .           3/r32/EBX   0xc/disp8       .                 # copy EDI+12 to EBX
    # maxt/EDX = t->data + t->write
    # . EAX = t->write
    8b/copy                         0/mod/indirect  7/rm32/EDI    .           .                         0/r32/EAX   .               .                 # copy *EDI to EAX
    # . maxt/EDX = t->data/EBX + t->write/EAX
    8d/copy-address                 0/mod/indirect  4/rm32/sib    3/base/EBX  0/index/EAX   .           2/r32/EDX   .               .                 # copy EBX+EAX to EDX
    # currt/EDI = t->data + t->read
    # . EAX = t/EDI->read
    8b/copy                         1/mod/*+disp8   7/rm32/EDI    .           .                         0/r32/EAX   4/disp8         .                 # copy *(EDI+4) to EAX
    # . currt/EDI = t->data/EBX + t->read/EAX
    8d/copy-address                 0/mod/indirect  4/rm32/sib    3/base/EBX  0/index/EAX   .           7/r32/EDI   .               .                 # copy EBX+EAX to EDI
$next-line-matches?:loop:
    # if (currl/ESI >= maxl/ECX) break
    39/compare                      3/mod/direct    6/rm32/ESI    .           .             .           1/r32/ECX   .               .                 # compare ESI and ECX
    73/jump-if-greater-or-equal-unsigned  $next-line-matches?:break/disp8
    # if (currt/EDI >= maxt/EDX) return false
    # . EAX = false
    b8/copy-to-EAX  0/imm32/false
    39/compare                      3/mod/direct    7/rm32/EDI    .           .             .           2/r32/EDX   .               .                 # compare EDI and EDX
    73/jump-if-greater-or-equal-unsigned  $next-line-matches?:end/disp8
    # if (*currt/EDI != *currl/ESI) return false
    31/xor                          3/mod/direct    0/rm32/EAX    .           .             .           0/r32/EAX   .               .                 # clear EAX
    31/xor                          3/mod/direct    3/rm32/EAX    .           .             .           3/r32/EAX   .               .                 # clear EBX
    # . EAX = (char) *currt/EDI
    8a/copy-byte                    0/mod/indirect  7/rm32/EDI    .           .                         0/r32/EAX   .               .                 # copy *EDI to EAX
    # . EBX = (char) *currl/ESI
    8a/copy-byte                    0/mod/indirect  6/rm32/ESI    .           .                         3/r32/EBX   .               .                 # copy *ESI to EBX
    # . EAX >= EBX
    39/compare                      3/mod/direct    0/rm32/EAX    .           .             .           3/r32/EBX   .               .                 # compare EAX and EBX
    # . EAX = false
    b8/copy-to-EAX  0/imm32/false
    75/jump-if-not-equal  $next-line-matches?:end/disp8
    # ++currt/EDI
    47/increment-EDI
    # ++currl/ESI
    46/increment-ESI
    eb/jump  $next-line-matches?:loop/disp8
$next-line-matches?:break:
    # return *currt == '\n'
    31/xor                          3/mod/direct    0/rm32/EAX    .           .             .           0/r32/EAX   .               .                 # clear EAX
    # . EAX = (char) *currt
    8a/copy-byte                    0/mod/indirect  7/rm32/EDI    .           .                         0/r32/EAX   .               .                 # copy *EDI to EAX
    3d/compare-EAX-and  0xa/imm32/newline
    # . EAX = false
    b8/copy-to-EAX  1/imm32/true
    74/jump-if-equal  $next-line-matches?:end/disp8
    b8/copy-to-EAX  0/imm32/true
$next-line-matches?: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

test-next-line-matches?-no-match-1:
    # next line of "ABABA" does not match "blah blah"
    # . EAX = next-line-matches?(_test-stream-line-ABABA, "blah blah")
    # . . push args
    68/push  "blah blah"/imm32
    68/push  _test-stream-line-ABABA/imm32
    # . . call
    e8/call  next-line-matches?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . check-ints-equal(EAX, 0, msg)
    # . . push args
    68/push  "F - test-next-line-matches?-no-match-1"/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
    c3/return

test-next-line-matches?-no-match-2:
    # next line of "ABABA" does not match ""
    # . EAX = next-line-matches?(_test-stream-line-ABABA, "")
    # . . push args
    68/push  ""/imm32
    68/push  _test-stream-line-ABABA/imm32
    # . . call
    e8/call  next-line-matches?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . check-ints-equal(EAX, 0, msg)
    # . . push args
    68/push  "F - test-next-line-matches?-no-match-2"/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
    c3/return

test-next-line-matches?-no-match-3:
    # next line of "ABABA" does not match  "AA"
    # . EAX = next-line-matches?(_test-stream-line-ABABA, "AA")
    # . . push args
    68/push  "AA"/imm32
    68/push  _test-stream-line-ABABA/imm32
    # . . call
    e8/call  next-line-matches?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . check-ints-equal(EAX, 0, msg)
    # . . push args
    68/push  "F - test-next-line-matches?-no-match-3"/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
    c3/return

test-next-line-matches?-match:
    # next line of "ABABA" matches "ABABA"
    # . EAX = next-line-matches?(_test-stream-line-ABABA, "ABABA")
    # . . push args
    68/push  "ABABA"/imm32
    68/push  _test-stream-line-ABABA/imm32
    # . . call
    e8/call  next-line-matches?/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
    68/push  "F - test-next-line-matches?-match"/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
    c3/return

# move t->read to _after_ next newline
skip-next-line:  # t : (address stream)
    # pseudocode:
    #   max = t->data + t->write
    #   i = t->read
    #   curr = t->data + t->read
    #   while true
    #     if (curr >= max) break
    #     ++i
    #     if (*curr == '\n') break
    #     ++curr
    #   t->read = i
    #
    # . 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
    # ECX = t
    8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .                         1/r32/ECX   8/disp8         .                 # copy *(EBP+8) to ECX
    # EDX = t/ECX->data
    8d/copy-address                 1/mod/*+disp8   1/rm32/ECX    .           .             .           2/r32/EDX   0xc/disp8       .                 # copy ECX+12 to EDX
    # EAX = t/ECX->write
    8b/copy                         0/mod/indirect  1/rm32/ECX    .           .             .           0/r32/EAX   .               .                 # copy *ECX to EAX
    # max/EBX = t->data/EDX + t->write/EAX
    8d/copy-address                 0/mod/indirect  4/rm32/sib    2/base/EDX  0/index/EAX   .           3/r32/EBX   .               .                 # copy EDX+EAX to EBX
    # EAX = t/ECX->read
    8b/copy                         1/mod/*+disp8   1/rm32/ECX    .           .             .           0/r32/EAX   4/disp8         .                 # copy *(ECX+4) to EDX
    # curr/ECX = t->data/EDX + t->read/EAX
    8d/copy-address                 0/mod/indirect  4/rm32/sib    2/base/EDX  0/index/EAX   .           1/r32/ECX   .               .                 # copy EDX+EAX to ECX
    # i/EDX = EAX
    8b/copy                         3/mod/direct    0/rm32/EAX    .           .             .           2/r32/EDX   .               .                 # copy EAX to EDX
$skip-next-line:loop:
    # if (curr/ECX >= max/EBX) break
    39/compare                      3/mod/direct    1/rm32/ECX    .           .             .           3/r32/EBX   .               .                 # compare ECX and EBX
    73/jump-if-greater-or-equal-unsigned  $skip-next-line:end/disp8
    # ++i/EDX
    42/increment-EDX
    # if (*curr/ECX == '\n') break
    31/xor                          3/mod/direct    0/rm32/EAX    .           .             .           0/r32/EAX   .               .                 # clear EAX
    8a/copy-byte                    0/mod/indirect  1/rm32/ECX    .           .             .           0/r32/EAX   .               .                 # copy *ECX to EAX
    3d/compare-EAX-and  0a/imm32/newline
    74/jump-if-equal  $skip-next-line:end/disp8
    # ++curr/ECX
    41/increment-ECX
    # loop
    eb/jump  $skip-next-line:loop/disp8
$skip-next-line:end:
    # ECX = t
    8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .                         1/r32/ECX   8/disp8         .                 # copy *(EBP+8) to ECX
    # t/ECX->read = i/EDX
    89/copy                         1/mod/*+disp8   1/rm32/ECX    .           .             .           2/r32/EDX   4/disp8         .                 # copy EDX to *(ECX+4)
    # . restore registers
    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-skip-next-line-empty:
    # skipping next line in empty stream leaves read pointer at 0
    # . skip-next-line(_test-stream-empty)
    # . . push args
    68/push  _test-stream-empty/imm32
    # . . call
    e8/call  skip-next-line/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # . check-ints-equal(_test-stream-empty->read, 0, msg)
    # . . push args
    68/push  "F - test-skip-next-line-empty"/imm32
    68/push  0/imm32
    b8/copy-to-EAX  _test-stream-empty/imm32
    8b/copy                         1/mod/*+disp8   0/rm32/EAX    .           .             .           0/r32/EAX   4/disp8         .                 # copy *(EAX+4) to EAX
    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-skip-next-line-filled:
    # skipping next line increments read pointer by length of line + 1 (for newline)
    # . skip-next-line(_test-stream-filled)
    # . . push args
    68/push  _test-stream-filled/imm32
    # . . call
    e8/call  skip-next-line/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # . check-ints-equal(_test-stream-filled->read, 5, msg)
    # . . push args
    68/push  "F - test-skip-next-line-filled"/imm32
    68/push  5/imm32
    b8/copy-to-EAX  _test-stream-filled/imm32
    8b/copy                         1/mod/*+disp8   0/rm32/EAX    .           .             .           0/r32/EAX   4/disp8         .                 # copy *(EAX+4) to EAX
    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

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
    73/jump-if-greater-or-equal-unsigned  $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
    73/jump-if-greater-or-equal-unsigned  $_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
    73/jump-if-greater-or-equal-unsigned  $_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\n"/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

== data

_test-stream-line-ABABA:
    # write
    8/imm32
    # read
    0/imm32
    # length
    8/imm32
    # data
    41 42 41 42 41 0A 00 00  # 8 bytes

_test-stream-empty:
    # write
    0/imm32
    # read
    0/imm32
    # length
    8/imm32
    # data
    00 00 00 00 00 00 00 00  # 8 bytes

_test-stream-filled:
    # write
    8/imm32
    # read
    0/imm32
    # length
    8/imm32
    # data
    41 41 41 41 0A 41 41 41  # 8 bytes

# . . vim:nowrap:textwidth=0