https://github.com/akkartik/mu/blob/master/subx/065error-byte.subx
 1 # Print an error message followed by the text representation of a byte. Then exit.
 2 
 3 == code
 4 #   instruction                     effective address                                                   register    displacement    immediate
 5 # . op          subop               mod             rm32          base        index         scale       r32
 6 # . 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
 7 
 8 # main:
 9     # manual test
10 #?     # . var ed/EAX : exit-descriptor
11 #?     81          5/subop/subtract    3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # subtract from ESP
12 #?     8d/copy-address                 0/mod/indirect  4/rm32/sib    4/base/ESP  4/index/none  .           0/r32/EAX   .               .                 # copy ESP to EAX
13 #?     # . configure ed to really exit()
14 #?     # . . ed->target = 0
15 #?     c7/copy                         0/mod/direct    0/rm32/EAX    .           .             .           .           .               0/imm32           # copy to *EAX
16 #?     # . error-byte(ed, Stdout, msg, 34)
17 #?     68/push  0x34/imm32
18 #?     68/push  "abc"/imm32
19 #?     68/push  Stdout/imm32
20 #?     50/push-EAX
21 #?     e8/call  error-byte/disp32
22     # automatic test
23     e8/call  run-tests/disp32  # 'run-tests' is a function created automatically by SubX. It calls all functions that start with 'test-'.
24     # . syscall(exit, Num-test-failures)
25     8b/copy                         0/mod/indirect  5/rm32/.disp32            .             .           3/r32/EBX   Num-test-failures/disp32          # copy *Num-test-failures to EBX
26     b8/copy-to-EAX  1/imm32
27     cd/syscall  0x80/imm8
28 
29 # write(out, "Error: "+msg+": "+byte) then stop(ed, 1)
30 error-byte:  # ed : (address exit-descriptor), out : (address buffered-file), msg : (address array byte), n : byte -> <void>
31     # . prolog
32     55/push-EBP
33     89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
34     # write-buffered(out, "Error: ")
35     # . . push args
36     68/push  "Error: "/imm32
37     ff          6/subop/push        1/mod/*+disp8   4/rm32/sib    5/base/EBP  4/index/none  .           .           0xc/disp8       .                 # push *(EBP+12)
38     # . . call
39     e8/call  write-buffered/disp32
40     # . . discard args
41     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
42     # write-buffered(out, msg)
43     # . . push args
44     ff          6/subop/push        1/mod/*+disp8   4/rm32/sib    5/base/EBP  4/index/none  .           .           0x10/disp8      .                 # push *(EBP+16)
45     ff          6/subop/push        1/mod/*+disp8   4/rm32/sib    5/base/EBP  4/index/none  .           .           0xc/disp8       .                 # push *(EBP+12)
46     # . . call
47     e8/call  write-buffered/disp32
48     # . . discard args
49     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
50     # write-buffered(out, ": ")
51     # . . push args
52     68/push  ": "/imm32
53     ff          6/subop/push        1/mod/*+disp8   4/rm32/sib    5/base/EBP  4/index/none  .           .           0xc/disp8       .                 # push *(EBP+12)
54     # . . call
55     e8/call  write-buffered/disp32
56     # . . discard args
57     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
58     # print-byte(out, byte)
59     # . . push args
60     ff          6/subop/push        1/mod/*+disp8   4/rm32/sib    5/base/EBP  4/index/none  .           .           0x14/disp8      .                 # push *(EBP+20)
61     ff          6/subop/push        1/mod/*+disp8   4/rm32/sib    5/base/EBP  4/index/none  .           .           0xc/disp8       .                 # push *(EBP+12)
62     # . . call
63     e8/call  print-byte/disp32
64     # . . discard args
65     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
66     # write-buffered(out, Newline)
67     # . . push args
68     68/push  Newline/imm32
69     ff          6/subop/push        1/mod/*+disp8   4/rm32/sib    5/base/EBP  4/index/none  .           .           0xc/disp8       .                 # push *(EBP+12)
70     # . . call
71     e8/call  write-buffered/disp32
72     # . . discard args
73     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
74     # . flush(out)
75     # . . push args
76     ff          6/subop/push        1/mod/*+disp8   4/rm32/sib    5/base/EBP  4/index/none  .           .           0xc/disp8       .                 # push *(EBP+12)
77     # . . call
78     e8/call  flush/disp32
79     # . . discard args
80     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
81     # stop(ed, 1)
82     # . . push args
83     68/push  1/imm32
84     ff          6/subop/push        1/mod/*+disp8   4/rm32/sib    5/base/EBP  4/index/none  .           .           8/disp8         .                 # push *(EBP+8)
85     # . . call
86     e8/call  stop/disp32
87     # should never get past this point
88 $error-byte:dead-end:
89     # . epilog
90     89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
91     5d/pop-to-EBP
92     c3/return
93 
94 # . . vim:nowrap:textwidth=0