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
|
# some common helpers shared by phases of the SubX converter
== 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
# (re)compute the bounds of the next word in the line
# return empty string on reaching end of file
next-word: # line : (address stream byte), out : (address slice)
# . 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
56/push-ESI
57/push-EDI
# ESI = line
8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 6/r32/ESI 8/disp8 . # copy *(EBP+8) to ESI
# EDI = out
8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 7/r32/EDI 0xc/disp8 . # copy *(EBP+12) to EDI
# skip-chars-matching(line, ' ')
# . . push args
68/push 0x20/imm32/space
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 8/disp8 . # push *(EBP+8)
# . . call
e8/call skip-chars-matching/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
$next-word:check0:
# if (line->read >= line->write) clear out and return
# . EAX = line->read
8b/copy 1/mod/*+disp8 6/rm32/ESI . . . 0/r32/EAX 4/disp8 . # copy *(ESI+4) to EAX
# . if (EAX < line->write) goto next check
3b/compare 0/mod/indirect 6/rm32/ESI . . . 0/r32/EAX . . # compare EAX with *ESI
7c/jump-if-lesser $next-word:check1/disp8
# . return out = {0, 0}
c7 0/subop/copy 0/mod/direct 7/rm32/EDI . . . . . 0/imm32 # copy to *EDI
c7 0/subop/copy 1/mod/*+disp8 7/rm32/EDI . . . . 4/disp8 0/imm32 # copy to *(EDI+4)
eb/jump $next-word:end/disp8
$next-word:check1:
# out->start = &line->data[line->read]
8b/copy 1/mod/*+disp8 6/rm32/ESI . . . 1/r32/ECX 4/disp8 . # copy *(ESI+4) to ECX
8d/copy-address 1/mod/*+disp8 4/rm32/sib 6/base/ESI 1/index/ECX . 0/r32/EAX 0xc/disp8 . # copy ESI+ECX+12 to EAX
89/copy 0/mod/indirect 7/rm32/EDI . . . 0/r32/EAX . . # copy EAX to *EDI
# if (line->data[line->read] == '#') out->end = &line->data[line->write]), skip rest of stream and return
# . EAX = line->data[line->read]
31/xor 3/mod/direct 0/rm32/EAX . . . 0/r32/EAX . . # clear EAX
8a/copy-byte 1/mod/*+disp8 4/rm32/sib 6/base/ESI 1/index/ECX . 0/r32/AL 0xc/disp8 . # copy byte at *(ESI+ECX+12) to AL
# . compare
3d/compare-EAX-and 0x23/imm32/pound
75/jump-if-not-equal $next-word:not-comment/disp8
# . out->end = &line->data[line->write]
8b/copy 0/mod/indirect 6/rm32/ESI . . . 0/r32/EAX . . # copy *ESI to EAX
8d/copy-address 1/mod/*+disp8 4/rm32/sib 6/base/ESI 0/index/EAX . 0/r32/EAX 0xc/disp8 . # copy ESI+EAX+12 to EAX
89/copy 1/mod/*+disp8 7/rm32/EDI . . . 0/r32/EAX 4/disp8 . # copy EAX to *(EDI+4)
# . line->read = line->write
89/copy 1/mod/*+disp8 6/rm32/ESI . . . 0/r32/EAX 4/disp8 . # copy EAX to *(ESI+4)
# . return
eb/jump $next-word:end/disp8
$next-word:not-comment:
# otherwise skip-chars-not-matching-whitespace(line) # including trailing newline
# . . push args
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 8/disp8 . # push *(EBP+8)
# . . call
e8/call skip-chars-not-matching-whitespace/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# out->end = &line->data[line->read]
8b/copy 1/mod/*+disp8 6/rm32/ESI . . . 1/r32/ECX 4/disp8 . # copy *(ESI+4) to ECX
8d/copy-address 1/mod/*+disp8 4/rm32/sib 6/base/ESI 1/index/ECX . 0/r32/EAX 0xc/disp8 . # copy ESI+ECX+12 to EAX
89/copy 1/mod/*+disp8 7/rm32/EDI . . . 0/r32/EAX 4/disp8 . # copy EAX to *(EDI+4)
$next-word:end:
# . restore registers
5f/pop-to-EDI
5e/pop-to-ESI
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-next-word:
# . prolog
55/push-EBP
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
# setup
# . clear-stream(_test-stream)
# . . push args
68/push _test-stream/imm32
# . . call
e8/call clear-stream/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# var slice/ECX = {0, 0}
68/push 0/imm32/end
68/push 0/imm32/start
89/copy 3/mod/direct 1/rm32/ECX . . . 4/r32/ESP . . # copy ESP to ECX
# write(_test-stream, " ab")
# . . push args
68/push " ab"/imm32
68/push _test-stream/imm32
# . . call
e8/call write/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# next-word(_test-stream, slice)
# . . push args
51/push-ECX
68/push _test-stream/imm32
# . . call
e8/call next-word/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# check-ints-equal(slice->start - _test-stream->data, 2, msg)
# . check-ints-equal(slice->start - _test-stream, 14, msg)
# . . push args
68/push "F - test-next-word: start"/imm32
68/push 0xe/imm32
# . . push slice->start - _test-stream
8b/copy 0/mod/indirect 1/rm32/ECX . . . 0/r32/EAX . . # copy *ECX to EAX
81 5/subop/subtract 3/mod/direct 0/rm32/EAX . . . . . _test-stream/imm32 # subtract from 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
# check-ints-equal(slice->end - _test-stream->data, 4, msg)
# . check-ints-equal(slice->end - _test-stream, 16, msg)
# . . push args
68/push "F - test-next-word: end"/imm32
68/push 0x10/imm32
# . . push slice->end - _test-stream
8b/copy 1/mod/*+disp8 1/rm32/ECX . . . 0/r32/EAX 4/disp8 . # copy *(ECX+4) to EAX
81 5/subop/subtract 3/mod/direct 0/rm32/EAX . . . . . _test-stream/imm32 # subtract from 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
# . epilog
89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP
5d/pop-to-EBP
c3/return
test-next-word-returns-whole-comment:
# . prolog
55/push-EBP
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
# setup
# . clear-stream(_test-stream)
# . . push args
68/push _test-stream/imm32
# . . call
e8/call clear-stream/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# var slice/ECX = {0, 0}
68/push 0/imm32/end
68/push 0/imm32/start
89/copy 3/mod/direct 1/rm32/ECX . . . 4/r32/ESP . . # copy ESP to ECX
# write(_test-stream, " # a")
# . . push args
68/push " # a"/imm32
68/push _test-stream/imm32
# . . call
e8/call write/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# next-word(_test-stream, slice)
# . . push args
51/push-ECX
68/push _test-stream/imm32
# . . call
e8/call next-word/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# check-ints-equal(slice->start - _test-stream->data, 2, msg)
# . check-ints-equal(slice->start - _test-stream, 14, msg)
# . . push args
68/push "F - test-next-word-returns-whole-comment: start"/imm32
68/push 0xe/imm32
# . . push slice->start - _test-stream
8b/copy 0/mod/indirect 1/rm32/ECX . . . 0/r32/EAX . . # copy *ECX to EAX
81 5/subop/subtract 3/mod/direct 0/rm32/EAX . . . . . _test-stream/imm32 # subtract from 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
# check-ints-equal(slice->end - _test-stream->data, 5, msg)
# . check-ints-equal(slice->end - _test-stream, 17, msg)
# . . push args
68/push "F - test-next-word-returns-whole-comment: end"/imm32
68/push 0x11/imm32
# . . push slice->end - _test-stream
8b/copy 1/mod/*+disp8 1/rm32/ECX . . . 0/r32/EAX 4/disp8 . # copy *(ECX+4) to EAX
81 5/subop/subtract 3/mod/direct 0/rm32/EAX . . . . . _test-stream/imm32 # subtract from 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
# . epilog
89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP
5d/pop-to-EBP
c3/return
test-next-word-returns-empty-string-on-eof:
# . prolog
55/push-EBP
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
# setup
# . clear-stream(_test-stream)
# . . push args
68/push _test-stream/imm32
# . . call
e8/call clear-stream/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
# var slice/ECX = {0, 0}
68/push 0/imm32/end
68/push 0/imm32/start
89/copy 3/mod/direct 1/rm32/ECX . . . 4/r32/ESP . . # copy ESP to ECX
# write nothing to _test-stream
# next-word(_test-stream, slice)
# . . push args
51/push-ECX
68/push _test-stream/imm32
# . . call
e8/call next-word/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
# check-ints-equal(slice->end - slice->start, 0, msg)
# . . push args
68/push "F - test-next-word-returns-empty-string-on-eof"/imm32
68/push 0/imm32
# . . push slice->end - slice->start
8b/copy 1/mod/*+disp8 1/rm32/ECX . . . 0/r32/EAX 4/disp8 . # copy *(ECX+4) to EAX
2b/subtract 0/mod/indirect 1/rm32/ECX . . . 0/r32/EAX . . # subtract *ECX from 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
# . epilog
89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP
5d/pop-to-EBP
c3/return
|