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
|
package j1
import "fmt"
// Decode instruction
func Decode(v uint16) Instruction {
switch {
case v&(1<<15) != 0:
return newLit(v)
case v&(7<<13) == 0:
return newJump(v)
case v&(7<<13) == 1<<13:
return newCond(v)
case v&(7<<13) == 2<<13:
return newCall(v)
case v&(7<<13) == 3<<13:
return newALU(v)
}
return nil
}
// Instruction interface
type Instruction interface {
Value() uint16
Compile() uint16
}
// Lit is a literal
type Lit uint16
func newLit(v uint16) Lit { return Lit(v &^ uint16(1<<15)) }
func (v Lit) String() string { return fmt.Sprintf("LIT %0.4X", uint16(v)) }
func (v Lit) Value() uint16 { return uint16(v) }
func (v Lit) Compile() uint16 { return v.Value() | (1 << 15) }
// Jump is an unconditional branch
type Jump uint16
func newJump(v uint16) Jump { return Jump(v &^ uint16(7<<13)) }
func (v Jump) String() string { return fmt.Sprintf("UBRANCH %0.4X", uint16(v<<1)) }
func (v Jump) Value() uint16 { return uint16(v) }
func (v Jump) Compile() uint16 { return v.Value() }
// Cond is a conditional branch
type Cond uint16
func newCond(v uint16) Cond { return Cond(v &^ uint16(7<<13)) }
func (v Cond) String() string { return fmt.Sprintf("0BRANCH %0.4X", uint16(v<<1)) }
func (v Cond) Value() uint16 { return uint16(v) }
func (v Cond) Compile() uint16 { return v.Value() | (1 << 13) }
// Call procedure
type Call uint16
func newCall(v uint16) Call { return Call(v &^ uint16(7<<13)) }
func (v Call) String() string { return fmt.Sprintf("CALL %0.4X", uint16(v<<1)) }
func (v Call) Value() uint16 { return uint16(v) }
func (v Call) Compile() uint16 { return v.Value() | (2 << 13) }
// ALU instruction
type ALU struct {
Opcode uint16
RtoPC bool
TtoN bool
TtoR bool
NtoAtT bool
Rdir int8
Ddir int8
}
func newALU(v uint16) ALU {
return ALU{
Opcode: (v >> 8) & 15,
RtoPC: v&(1<<12) != 0,
TtoN: v&(1<<7) != 0,
TtoR: v&(1<<6) != 0,
NtoAtT: v&(1<<5) != 0,
Rdir: expand((v >> 2) & 3),
Ddir: expand(v & 3),
}
}
func (v ALU) Value() uint16 {
ret := v.Opcode << 8
if v.RtoPC {
ret |= 1 << 12
}
if v.TtoN {
ret |= 1 << 7
}
if v.TtoR {
ret |= 1 << 6
}
if v.NtoAtT {
ret |= 1 << 5
}
ret |= uint16(v.Rdir&3) << 2
ret |= uint16(v.Ddir & 3)
return ret
}
func (v ALU) Compile() uint16 { return v.Value() | (3 << 13) }
func expand(v uint16) int8 {
if v&2 != 0 {
v |= 0xfc
}
return int8(v)
}
const (
opT = iota // 0
opN // 1
opTplusN // 2
opTandN // 3
opTorN // 4
opTxorN // 5
opNotT // 6
opNeqT // 7
opNleT // 8
opNrshiftT // 9
opTminus1 // 10
opR // 11
opAtT // 12
opNlshiftT // 13
opDepth // 14
opNuleT // 15
)
var opcodeNames = []string{
"T", "N", "T+N", "T&N", "T|N", "T^N", "~T", "N==T",
"N<T", "N>>T", "T-1", "R", "[T]", "N<<T", "depth", "Nu<T",
}
func (v ALU) String() string {
s := "ALU " + opcodeNames[v.Opcode]
if v.RtoPC {
s += " R→PC"
}
if v.TtoN {
s += " T→N"
}
if v.TtoR {
s += " T→R"
}
if v.NtoAtT {
s += " N→[T]"
}
if v.Rdir != 0 {
s += fmt.Sprintf(" r%+d", v.Rdir)
}
if v.Ddir != 0 {
s += fmt.Sprintf(" d%+d", v.Ddir)
}
return s
}
|