1 # Rudimentary test harness
 2 
 3 == code
 4 # instruction                     effective address                                                   operand     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:  (manual test if this is the last file loaded)
 9   # check-ints-equal(34, 34)
10   68/push  "error in check-ints-equal"/imm32
11   68/push  34/imm32
12   68/push  34/imm32
13   e8/call  check-ints-equal/disp32
14   81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
15   # syscall(exit, 0)
16   bb/copy-to-EBX  0/imm32
17   b8/copy-to-EAX  1/imm32
18   cd/syscall  0x80/imm8
19 
20 # print msg to stderr if a != b, otherwise print "."
21 check-ints-equal:  # (a : int, b : int, msg : (address array byte)) -> boolean
22   # prolog
23   55/push-EBP
24   89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
25   # save registers
26   51/push-ECX
27   53/push-EBX
28   # load first 2 args into EAX and EBX
29   8b/copy                         1/mod/*+disp8   4/rm32/sib    5/base/EBP  4/index/none  .           0/r32/EAX   0x8/disp8       .                 # copy *(EBP+8) to EAX
30   8b/copy                         1/mod/*+disp8   4/rm32/sib    5/base/EBP  4/index/none  .           3/r32/EBX   0xc/disp8       .                 # copy *(EBP+12) to EBX
31   # if EAX == b/EBX
32   39/compare                      3/mod/direct    0/rm32/EAX    .           .             .           3/r32/EBX   .               .                 # compare EAX and EBX
33   75/jump-if-unequal  $check-ints-equal:else/disp8
34     # _write(2/stderr, '.')
35       # push args
36   68/push  "."/imm32
37   68/push  2/imm32/stderr
38       # call
39   e8/call  _write/disp32
40       # discard args
41   81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
42     # return
43   eb/jump  $check-ints-equal:end/disp8
44   # else:
45 $check-ints-equal:else:
46     # _write(2/stderr, msg)
47       # push args
48   8b/copy                         1/mod/*+disp8   4/rm32/sib    5/base/EBP  4/index/none  .           1/r32/ECX   0x10/disp8      .                 # copy *(EBP+16) to ECX
49   51/push-ECX
50   68/push  2/imm32/stderr
51       # call
52   e8/call  _write/disp32
53       # discard args
54   81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
55     # _write(2/stderr, Newline)
56       # push args
57   68/push  Newline/imm32
58   68/push  2/imm32/stderr
59       # call
60   e8/call  _write/disp32
61       # discard args
62   81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
63     # increment Num-test-failures
64   ff          0/subop/increment   0/mod/indirect  5/rm32/.disp32            .             .           .           Num-test-failures/disp32          # increment *Num-test-failures
65 $check-ints-equal:end:
66   # restore registers
67   5b/pop-to-EBX
68   59/pop-to-ECX
69   # epilog
70   89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
71   5d/pop-to-EBP
72   c3/return
73 
74 == data
75 
76 Newline:
77   # size
78   01 00 00 00
79   # data
80   0a/newline
81 
82 Num-test-failures:
83   00 00 00 00
84 
85 # vim:nowrap:textwidth=0