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
252
253
254
255
256
257
258
259
260
|
## Mu's instructions and their table-driven translation
See http://akkartik.name/akkartik-convivial-20200315.pdf for the complete
story. In brief: Mu is a statement-oriented language. Blocks consist of flat
lists of instructions. Instructions can have inputs after the operation, and
outputs to the left of a '<-'. Inputs and outputs must be variables. They can't
include nested expressions. Variables can be literals ('n'), or live in a
register ('var/reg') or in memory ('var') at some 'stack-offset' from the 'ebp'
register. Outputs must be registers. To modify a variable in memory, pass it in
by reference as an input. (Inputs are more precisely called 'inouts'.)
Conversely, registers that are just read from must not be passed as inputs.
The following chart shows all the instruction forms supported by Mu, along with
the SubX instruction they're translated to.
var/eax <- increment => "40/increment-eax"
var/ecx <- increment => "41/increment-ecx"
var/edx <- increment => "42/increment-edx"
var/ebx <- increment => "43/increment-ebx"
var/esi <- increment => "46/increment-esi"
var/edi <- increment => "47/increment-edi"
increment var => "ff 0/subop/increment *(ebp+" var.stack-offset ")"
increment *var/reg => "ff 0/subop/increment *" reg
var/eax <- decrement => "48/decrement-eax"
var/ecx <- decrement => "49/decrement-ecx"
var/edx <- decrement => "4a/decrement-edx"
var/ebx <- decrement => "4b/decrement-ebx"
var/esi <- decrement => "4e/decrement-esi"
var/edi <- decrement => "4f/decrement-edi"
decrement var => "ff 1/subop/decrement *(ebp+" var.stack-offset ")"
decrement *var/reg => "ff 1/subop/decrement *" reg
var/reg <- add var2/reg2 => "01/add-to %" reg " " reg2 "/r32"
var/reg <- add var2 => "03/add *(ebp+" var2.stack-offset ") " reg "/r32"
var/reg <- add *var2/reg2 => "03/add *" reg2 " " reg "/r32"
add-to var1, var2/reg => "01/add-to *(ebp+" var1.stack-offset ") " reg "/r32"
var/eax <- add n => "05/add-to-eax " n "/imm32"
var/reg <- add n => "81 0/subop/add %" reg " " n "/imm32"
add-to var, n => "81 0/subop/add *(ebp+" var.stack-offset ") " n "/imm32"
add-to *var/reg, n => "81 0/subop/add *" reg " " n "/imm32"
var/reg <- subtract var2/reg2 => "29/subtract-from %" reg " " reg2 "/r32"
var/reg <- subtract var2 => "2b/subtract *(ebp+" var2.stack-offset ") " reg "/r32"
var/reg <- subtract *var2/reg2 => "2b/subtract *" reg2 " " reg1 "/r32"
subtract-from var1, var2/reg2 => "29/subtract-from *(ebp+" var1.stack-offset ") " reg2 "/r32"
var/eax <- subtract n => "2d/subtract-from-eax " n "/imm32"
var/reg <- subtract n => "81 5/subop/subtract %" reg " " n "/imm32"
subtract-from var, n => "81 5/subop/subtract *(ebp+" var.stack-offset ") " n "/imm32"
subtract-from *var/reg, n => "81 5/subop/subtract *" reg " " n "/imm32"
var/reg <- and var2/reg2 => "21/and-with %" reg " " reg2 "/r32"
var/reg <- and var2 => "23/and *(ebp+" var2.stack-offset " " reg "/r32"
var/reg <- and *var2/reg2 => "23/and *" reg2 " " reg "/r32"
and-with var1, var2/reg => "21/and-with *(ebp+" var1.stack-offset ") " reg "/r32"
var/eax <- and n => "25/and-with-eax " n "/imm32"
var/reg <- and n => "81 4/subop/and %" reg " " n "/imm32"
and-with var, n => "81 4/subop/and *(ebp+" var.stack-offset ") " n "/imm32"
and-with *var/reg, n => "81 4/subop/and *" reg " " n "/imm32"
var/reg <- or var2/reg2 => "09/or-with %" reg " " reg2 "/r32"
var/reg <- or var2 => "0b/or *(ebp+" var2.stack-offset ") " reg "/r32"
var/reg <- or *var2/reg2 => "0b/or *" reg2 " " reg "/r32"
or-with var1, var2/reg2 => "09/or-with *(ebp+" var1.stack-offset " " reg2 "/r32"
var/eax <- or n => "0d/or-with-eax " n "/imm32"
var/reg <- or n => "81 1/subop/or %" reg " " n "/imm32"
or-with var, n => "81 1/subop/or *(ebp+" var.stack-offset ") " n "/imm32"
or-with *var/reg, n => "81 1/subop/or *" reg " " n "/imm32"
var/reg <- xor var2/reg2 => "31/xor-with %" reg " " reg2 "/r32"
var/reg <- xor var2 => "33/xor *(ebp+" var2.stack-offset ") " reg "/r32"
var/reg <- xor *var2/reg2 => "33/xor *" reg2 " " reg "/r32"
xor-with var1, var2/reg => "31/xor-with *(ebp+" var1.stack-offset ") " reg "/r32"
var/eax <- xor n => "35/xor-with-eax " n "/imm32"
var/reg <- xor n => "81 6/subop/xor %" reg " " n "/imm32"
xor-with var, n => "81 6/subop/xor *(ebp+" var.stack-offset ") " n "/imm32"
xor-with *var/reg, n => "81 6/subop/xor *" reg " " n "/imm32"
var/reg <- shift-left n
var/reg <- shift-right n
var/reg <- shift-right-signed n
shift-left var, n
shift-right var, n
shift-right-signed var, n
var/eax <- copy n => "b8/copy-to-eax " n "/imm32"
var/ecx <- copy n => "b9/copy-to-ecx " n "/imm32"
var/edx <- copy n => "ba/copy-to-edx " n "/imm32"
var/ebx <- copy n => "bb/copy-to-ebx " n "/imm32"
var/esi <- copy n => "be/copy-to-esi " n "/imm32"
var/edi <- copy n => "bf/copy-to-edi " n "/imm32"
var/reg <- copy var2/reg2 => "89/<- %" reg " " reg2 "/r32"
copy-to var1, var2/reg => "89/<- *(ebp+" var1.stack-offset ") " reg "/r32"
var/reg <- copy var2 => "8b/-> *(ebp+" var2.stack-offset ") " reg "/r32"
var/reg <- copy *var2/reg2 => "8b/-> *" reg2 " " reg "/r32"
var/reg <- copy n => "c7 0/subop/copy %" reg " " n "/imm32"
copy-to var, n => "c7 0/subop/copy *(ebp+" var.stack-offset ") " n "/imm32"
copy-to *var/reg, n => "c7 0/subop/copy *" reg " " n "/imm32"
var/reg <- copy-byte var2/reg2 => "8a/byte-> %" reg2 " " reg "/r32"
var/reg <- copy-byte *var2/reg2 => "8a/byte-> *" reg2 " " reg "/r32"
copy-byte-to *var1/reg1, var2/reg2 => "88/byte<- *" reg1 " " reg2 "/r32"
compare var1, var2/reg2 => "39/compare *(ebp+" var1.stack-offset ") " reg2 "/r32"
compare *var1/reg1, var2/reg2 => "39/compare *" reg1 " " reg2 "/r32"
compare var1/reg1, var2 => "3b/compare<- *(ebp+" var2.stack-offset ") " reg1 "/r32"
compare var/reg, *var2/reg2 => "3b/compare<- *" reg " " n "/imm32"
compare var/eax, n => "3d/compare-eax-with " n "/imm32"
compare var/reg, n => "81 7/subop/compare %" reg " " n "/imm32"
compare var, n => "81 7/subop/compare *(ebp+" var.stack-offset ") " n "/imm32"
compare *var/reg, n => "81 7/subop/compare *" reg " " n "/imm32"
var/reg <- multiply var2 => "0f af/multiply *(ebp+" var2.stack-offset ") " reg "/r32"
var/reg <- multiply *var2/reg2 => "0f af/multiply *" reg2 " " reg "/r32"
break => "e9/jump break/disp32"
break label => "e9/jump " label ":break/disp32"
loop => "e9/jump loop/disp32"
loop label => "e9/jump " label ":loop/disp32"
break-if-= => "0f 84/jump-if-= break/disp32"
break-if-= label => "0f 84/jump-if-= " label ":break/disp32"
loop-if-= => "0f 84/jump-if-= loop/disp32"
loop-if-= label => "0f 84/jump-if-= " label ":loop/disp32"
break-if-!= => "0f 85/jump-if-!= break/disp32"
break-if-!= label => "0f 85/jump-if-!= " label ":break/disp32"
loop-if-!= => "0f 85/jump-if-!= loop/disp32"
loop-if-!= label => "0f 85/jump-if-!= " label ":loop/disp32"
break-if-< => "0f 8c/jump-if-< break/disp32"
break-if-< label => "0f 8c/jump-if-< " label ":break/disp32"
loop-if-< => "0f 8c/jump-if-< loop/disp32"
loop-if-< label => "0f 8c/jump-if-< " label ":loop/disp32"
break-if-> => "0f 8f/jump-if-> break/disp32"
break-if-> label => "0f 8f/jump-if-> " label ":break/disp32"
loop-if-> => "0f 8f/jump-if-> loop/disp32"
loop-if-> label => "0f 8f/jump-if-> " label ":loop/disp32"
break-if-<= => "0f 8e/jump-if-<= break/disp32"
break-if-<= label => "0f 8e/jump-if-<= " label ":break/disp32"
loop-if-<= => "0f 8e/jump-if-<= loop/disp32"
loop-if-<= label => "0f 8e/jump-if-<= " label ":loop/disp32"
break-if->= => "0f 8d/jump-if->= break/disp32"
break-if->= label => "0f 8d/jump-if->= " label ":break/disp32"
loop-if->= => "0f 8d/jump-if->= loop/disp32"
loop-if->= label => "0f 8d/jump-if->= " label ":loop/disp32"
break-if-addr< => "0f 82/jump-if-addr< break/disp32"
break-if-addr< label => "0f 82/jump-if-addr< " label ":break/disp32"
loop-if-addr< => "0f 82/jump-if-addr< loop/disp32"
loop-if-addr< label => "0f 82/jump-if-addr< " label ":loop/disp32"
break-if-addr> => "0f 87/jump-if-addr> break/disp32"
break-if-addr> label => "0f 87/jump-if-addr> " label ":break/disp32"
loop-if-addr> => "0f 87/jump-if-addr> loop/disp32"
loop-if-addr> label => "0f 87/jump-if-addr> " label ":loop/disp32"
break-if-addr<= => "0f 86/jump-if-addr<= break/disp32"
break-if-addr<= label => "0f 86/jump-if-addr<= " label ":break/disp32"
loop-if-addr<= => "0f 86/jump-if-addr<= loop/disp32"
loop-if-addr<= label => "0f 86/jump-if-addr<= " label ":loop/disp32"
break-if-addr>= => "0f 83/jump-if-addr>= break/disp32"
break-if-addr>= label => "0f 83/jump-if-addr>= " label ":break/disp32"
loop-if-addr>= => "0f 83/jump-if-addr>= loop/disp32"
loop-if-addr>= label => "0f 83/jump-if-addr>= " label ":loop/disp32"
In the following instructions types are provided for clarity even if they must
be provided in an earlier 'var' declaration.
# Address operations
var/reg: (addr T) <- address var2: T
=> "8d/copy-address *(ebp+" var2.stack-offset ") " reg "/r32"
# Array operations
(TODO: bounds-checking)
var/reg <- index arr/rega: (addr array T), idx/regi: int
| if size-of(T) is 4 or 8
=> "8d/copy-address *(" rega "+" regi "<<" log2(size-of(T)) "+4) " reg "/r32"
var/reg <- index arr: (array T sz), idx/regi: int
=> "8d/copy-address *(ebp+" regi "<<" log2(size-of(T)) "+" (arr.stack-offset + 4) ") " reg "/r32"
var/reg <- index arr/rega: (addr array T), n
=> "8d/copy-address *(" rega "+" (n*size-of(T)+4) ") " reg "/r32"
var/reg <- index arr: (array T sz), n
=> "8d/copy-address *(ebp+" (arr.stack-offset+4+n*size-of(T)) ") " reg "/r32"
var/reg: (offset T) <- compute-offset arr: (addr array T), idx/regi: int # arr can be in reg or mem
=> "69/multiply %" regi " " size-of(T) "/imm32 " reg "/r32"
var/reg: (offset T) <- compute-offset arr: (addr array T), idx: int # arr can be in reg or mem
=> "69/multiply *(ebp+" idx.stack-offset ") " size-of(T) "/imm32 " reg "/r32"
var/reg <- index arr/rega: (addr array T), o/rego: offset
=> "8d/copy-address *(" rega "+" rego "+4) " reg "/r32"
Computing the length of an array is complex.
var/reg <- length arr/reg2: (addr array T)
| if T is byte (TODO)
=> "8b/-> *" reg2 " " reg "/r32"
| if size-of(T) is 4 or 8 or 16 or 32 or 64 or 128
=> "8b/-> *" reg2 " " reg "/r32"
"c1/shift 5/subop/logic-right %" reg " " log2(size-of(T)) "/imm8"
| otherwise
x86 has no instruction to divide by a literal, so
we need up to 3 extra registers! eax/edx for division and say ecx
=> if reg is not eax
"50/push-eax"
if reg is not ecx
"51/push-ecx"
if reg is not edx
"52/push-edx"
"8b/-> *" reg2 " eax/r32"
"31/xor %edx 2/r32/edx" # sign-extend, but array size can't be negative
"b9/copy-to-ecx " size-of(T) "/imm32"
"f7 7/subop/idiv-eax-edx-by %ecx"
if reg is not eax
"89/<- %" reg " 0/r32/eax"
if reg is not edx
"5a/pop-to-edx"
if reg is not ecx
"59/pop-to-ecx"
if reg is not eax
"58/pop-to-eax"
# User-defined types
If a record (product) type T was defined to have elements a, b, c, ... of
types T_a, T_b, T_c, ..., then accessing one of those elements f of type T_f:
var/reg: (addr T_f) <- get var2/reg2: (addr T), f
=> "8d/copy-address *(" reg2 "+" offset(f) ") " reg "/r32"
var/reg: (addr T_f) <- get var2: T, f
=> "8d/copy-address *(ebp+" var2.stack-offset "+" offset(f) ") " reg "/r32"
# Handles for safe access to the heap
out/reg: (addr T) <- lookup in: (handle T)
=> # payload_allocid = in->address->allocid
"8b/-> *(epb+" (in.stack-offset+4) ") " reg "/r32"
"8b/-> *" reg " " reg "/r32"
# if (payload_allocid != handle->allocid) abort
"39/compare *(ebp+" in.stack-offset ") " reg "/r32"
"0f 85/jump-if-!= $lookup:abort/disp32"
# return payload
"8b/-> *(epb+" (in.stack-offset+4) ") " reg "/r32"
"81 0/subop/add %" reg " 4/imm32" # skip payload->allocid
# Allocating memory
allocate in: (addr handle T)
=> "(allocate Heap " size-of(T) " " in ")"
populate in: (addr handle array T), num # can be literal or variable on stack or register
=> "(allocate-array2 Heap " size-of(T) " " num " " in ")"
vim:ft=mu:nowrap:textwidth=0
|