blob: 518ed0de4257898dfc0eb7fd8898c8f677a10941 (
plain) (
blame)
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
|
# Rudimentary test harness
== code
# instruction effective address register displacement immediate
# . op subop mod rm32 base index scale r32
# . 1-3 bytes 3 bits 2 bits 3 bits 3 bits 3 bits 2 bits 2 bits 0/1/2/4 bytes 0/1/2/4 bytes
Entry: # manual test
# check-ints-equal(34, 34)
# . . push args
68/push "error in check-ints-equal"/imm32
68/push 34/imm32
68/push 34/imm32
# . . call
e8/call check-ints-equal/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp
# syscall(exit, 0)
bb/copy-to-ebx 0/imm32
b8/copy-to-eax 1/imm32/exit
cd/syscall 0x80/imm8
# print msg to stderr if a != b, otherwise print "."
check-ints-equal: # a: int, b: int, msg: (addr array byte)
# . prologue
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
53/push-ebx
# load first 2 args into eax and ebx
8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 0/r32/eax 8/disp8 . # copy *(ebp+8) to eax
8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 3/r32/ebx 0xc/disp8 . # copy *(ebp+12) to ebx
# if (eax == ebx) success
39/compare 3/mod/direct 0/rm32/eax . . . 3/r32/ebx . . # compare eax and ebx
75/jump-if-unequal $check-ints-equal:else/disp8
# . _write(2/stderr, '.')
# . . push args
68/push "."/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
# . return
eb/jump $check-ints-equal:end/disp8
# otherwise print error message
$check-ints-equal:else:
# . _write(2/stderr, msg)
# . . push args
8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 1/r32/ecx 0x10/disp8 . # copy *(ebp+16) to ecx
51/push-ecx
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
# . _write(2/stderr, Newline)
# . . push args
68/push Newline/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
# increment Num-test-failures
ff 0/subop/increment 0/mod/indirect 5/rm32/.disp32 . . . Num-test-failures/disp32 # increment *Num-test-failures
$check-ints-equal:end:
# . restore registers
5b/pop-to-ebx
59/pop-to-ecx
58/pop-to-eax
# . epilogue
89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp
5d/pop-to-ebp
c3/return
== data
# length-prefixed string containing just a single newline
# convenient to have when printing messages and so on
Newline: # (array byte)
# size: int
1/imm32
# data
0a/newline
# every test failure increments this counter
Num-test-failures: # int
0/imm32
# length-prefixed string containing just a single space
Space: # (array byte)
# size: int
1/imm32
# data
20/space
# length-prefixed string containing just a single slash
Slash: # (array byte)
# size: int
1/imm32
# data
2f/slash
# . . vim:nowrap:textwidth=0
|