blob: 04f4dee6a733753b776e97fec06ff841a321c4d3 (
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
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
|
(define-library (csc encoding)
(export encode int->le-bytes)
(import (scheme base)
(prefix (csc list) list.)
(prefix (csc map) map.))
(begin
; I'm only going to say this once, so pay attention.
; The format of unboxed constants is described in bytecocde/src/data.rs.
; Boxed values are represented by a pointer to an array on the heap. The
; first position in the array is an integer code indicating what type the
; object is. Vectors have code 0, pairs have code 2, and codes for other
; types are not stable. Vectors are represented as an array, the first
; element of which is the integer 0 (the type code), the second element is
; the vector length, and the remaining slots hold the array values.
(define-syntax mlength
(syntax-rules ()
((mlength ()) 0)
((mlength (_ l ...)) (+ 1 (mlength (l ...))))))
(define-syntax match-clause
(syntax-rules ()
((match-clause op n ((code arg1 arg2 ...) body ...) clause* ...)
(if (and (= n (mlength (code arg1 arg2 ...)))
(symbol=? (car op) code))
(let-values (((arg1 arg2 ...) (apply values (cdr op))))
body ...)
(match-clause op n clause* ...)))
((match-clause _ _ (else body ...))
(begin body ...))))
(define-syntax match
(syntax-rules ()
((match op clause* ...)
(let ((n (length op)))
(match-clause op n clause* ...)))))
(define (make-label-map program)
(let loop ((program program)
(i 0)
(m (map.empty -)))
(if (null? program)
m
(match (car program)
(('label id)
(loop (cdr program)
i
(map.insert m id i)))
(else (loop (cdr program)
(+ 1 i)
m))))))
; Rewrites each (label x) form into a integer constant.
(define (translate-labels program)
(define label-map (make-label-map program))
(list.map-maybe
(lambda (opcode)
(match opcode
(('label x) #f)
(else
(let ((op (car opcode))
(args (cdr opcode)))
(cons op
(map
(lambda (arg)
(match arg
(('label x)
(list 'const (map.lookup label-map x)))
(else arg)))
args))))))
program))
(define (low-byte w n)
(write-u8 (remainder n #x100) w))
(define (64->le-bytes w n)
(low-byte w n)
(low-byte w (quotient n #x100))
(low-byte w (quotient n #x10000))
(low-byte w (quotient n #x1000000))
(low-byte w (quotient n #x100000000))
(low-byte w (quotient n #x10000000000))
(low-byte w (quotient n #x1000000000000))
(low-byte w (quotient n #x100000000000000)))
(define (int->le-bytes w n)
(when (or (>= n #x4000000000000000)
(< n #x-4000000000000000))
(error "int constant too large" n))
(when (negative? n)
(set! n (+ #x10000000000000000 n)))
(64->le-bytes w (+ 1 (* 2 n))))
(define (bool->le-bytes w b)
(if b
(64->le-bytes w #xa)
(64->le-bytes w #x2)))
(define (const->le-bytes w x)
(cond
((integer? x)
(int->le-bytes w x))
((boolean? x)
(bool->le-bytes w x))
((null? x)
(64->le-bytes w #x12))
(else (error "unexpected type in const->le-bytes" x))))
(define (make-opcode w code arg1-const arg2-const)
(when (>= code #x40)
(error "code is more than 6 bits" code))
(define arg1-bit (if arg1-const
2
0))
(define arg2-bit (if arg2-const
1
0))
(write-u8 (+ (* 4 code) arg1-bit arg2-bit) w))
(define (arg->le-bytes w atom)
(match atom
(('const val) (const->le-bytes w val))
(('local i)
(when (>= i #x100)
(error "local index is out of range" i))
(write-u8 i w))
(else (error "unexpected form in arg->le-bytes" atom))))
(define (is-const? atom)
(match atom
(('const x) #t)
(else #f)))
(define (opcode-switch w opcode)
(match opcode
(('mov dest src)
(make-opcode w 0 (is-const? src) #f)
(arg->le-bytes w dest)
(arg->le-bytes w src))
(('jmpif test dest)
(make-opcode w 1 (is-const? test) (is-const? dest))
(arg->le-bytes w test)
(arg->le-bytes w dest))
(('jmp dest)
(make-opcode w 2 (is-const? dest) #f)
(arg->le-bytes w dest))
(('alloc dest size)
(make-opcode w 3 (is-const? size) #f)
(arg->le-bytes w dest)
(arg->le-bytes w size))
(('peek dest ptr offset)
(make-opcode w 4 (is-const? ptr) (is-const? offset)) ; ptr will likely never be constant.
(arg->le-bytes w dest)
(arg->le-bytes w ptr)
(arg->le-bytes w offset))
(('poke word ptr offset)
; We only have 2 bits to store whether the arguments are const, but
; it's actually true that a pointer can never be a constant. So we
; only track whether the word and offset arguments are constant, and
; assume ptr will always be a one-byte register name.
(make-opcode w 5 (is-const? word) (is-const? offset))
(arg->le-bytes w word)
(arg->le-bytes w ptr)
(arg->le-bytes w offset))
(('add dest x y)
(make-opcode w 6 (is-const? x) (is-const? y))
(arg->le-bytes w dest)
(arg->le-bytes w x)
(arg->le-bytes w y))
(('sub dest x y)
(make-opcode w 7 (is-const? x) (is-const? y))
(arg->le-bytes w dest)
(arg->le-bytes w x)
(arg->le-bytes w y))
(('mul dest x y)
(make-opcode w 8 (is-const? x) (is-const? y))
(arg->le-bytes w dest)
(arg->le-bytes w x)
(arg->le-bytes w y))
(('div dest x y)
(make-opcode w 9 (is-const? x) (is-const? y))
(arg->le-bytes w dest)
(arg->le-bytes w x)
(arg->le-bytes w y))
(('mod dest x y)
(make-opcode w 10 (is-const? x) (is-const? y))
(arg->le-bytes w dest)
(arg->le-bytes w x)
(arg->le-bytes w y))
(('peekbyte dest ptr offset)
(make-opcode w 11 (is-const? ptr) (is-const? offset))
(arg->le-bytes w dest)
(arg->le-bytes w ptr)
(arg->le-bytes w offset))
(('pokebyte word ptr offset)
(make-opcode w 12 (is-const? word) (is-const? offset))
(arg->le-bytes w word)
(arg->le-bytes w ptr)
(arg->le-bytes w offset))
(('exit code)
(make-opcode w 13 (is-const? code) #f)
(arg->le-bytes w code))
(('alloc-bytevector dest size)
(make-opcode w 14 (is-const? size) #f)
(arg->le-bytes w dest)
(arg->le-bytes w size))
(('typeof dest x)
(make-opcode w 15 (is-const? x) #f)
(arg->le-bytes w dest)
(arg->le-bytes w x))
(('lt dest x y)
(make-opcode w 16 (is-const? x) (is-const? y))
(arg->le-bytes w dest)
(arg->le-bytes w x)
(arg->le-bytes w y))
(('eq dest x y)
(make-opcode w 17 (is-const? x) (is-const? y))
(arg->le-bytes w dest)
(arg->le-bytes w x)
(arg->le-bytes w y))
(('cons dest x y)
(make-opcode w 18 (is-const? x) (is-const? y))
(arg->le-bytes w dest)
(arg->le-bytes w x)
(arg->le-bytes w y))
(else (error "invalid opcode" opcode))))
(define (encode program)
(define out (open-output-bytevector))
(map (lambda (op) (opcode-switch out op)) (translate-labels program))
(get-output-bytevector out))))
|
