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
|
package main
import (
_"math"
"math/big"
"fmt"
_"strconv"
_ "encoding/hex"
"strconv"
)
// Op codes
const (
oSTOP int = 0x00
oADD int = 0x01
oMUL int = 0x02
oSUB int = 0x03
oDIV int = 0x04
oSDIV int = 0x05
oMOD int = 0x06
oSMOD int = 0x07
oEXP int = 0x08
oNEG int = 0x09
oLT int = 0x0a
oLE int = 0x0b
oGT int = 0x0c
oGE int = 0x0d
oEQ int = 0x0e
oNOT int = 0x0f
oMYADDRESS int = 0x10
oTXSENDER int = 0x11
oPUSH int = 0x30
oPOP int = 0x31
oLOAD int = 0x36
)
type OpType int
const (
tNorm = iota
tData
tExtro
tCrypto
)
type TxCallback func(opType OpType) bool
// Simple push/pop stack mechanism
type Stack struct {
data []string
}
func NewStack() *Stack {
return &Stack{}
}
func (st *Stack) Pop() string {
s := len(st.data)
str := st.data[s-1]
st.data = st.data[:s-1]
return str
}
func (st *Stack) Popn() (*big.Int, *big.Int) {
s := len(st.data)
strs := st.data[s-2:]
st.data = st.data[:s-2]
return Big(strs[0]), Big(strs[1])
}
func (st *Stack) Push(d string) {
st.data = append(st.data, d)
}
func (st *Stack) Print() {
fmt.Println(st.data)
}
type Vm struct {
// Stack
stack *Stack
}
func NewVm() *Vm {
return &Vm{
stack: NewStack(),
}
}
func (vm *Vm) ProcContract(tx *Transaction, block *Block, cb TxCallback) {
// Instruction pointer
pc := 0
contract := block.GetContract(tx.Hash())
if contract == nil {
fmt.Println("Contract not found")
return
}
Pow256 := BigPow(2, 256)
//fmt.Printf("# op arg\n")
out:
for {
// The base big int for all calculations. Use this for any results.
base := new(big.Int)
// XXX Should Instr return big int slice instead of string slice?
// Get the next instruction from the contract
//op, _, _ := Instr(contract.state.Get(string(Encode(uint32(pc)))))
op, _, _ := Instr(contract.state.Get(string(NumberToBytes(uint64(pc), 32))))
if !cb(0) { break }
if Debug {
//fmt.Printf("%-3d %-4d\n", pc, op)
}
switch op {
case oADD:
x, y := vm.stack.Popn()
// (x + y) % 2 ** 256
base.Add(x, y)
base.Mod(base, Pow256)
// Pop result back on the stack
vm.stack.Push(base.String())
case oSUB:
x, y := vm.stack.Popn()
// (x - y) % 2 ** 256
base.Sub(x, y)
base.Mod(base, Pow256)
// Pop result back on the stack
vm.stack.Push(base.String())
case oMUL:
x, y := vm.stack.Popn()
// (x * y) % 2 ** 256
base.Mul(x, y)
base.Mod(base, Pow256)
// Pop result back on the stack
vm.stack.Push(base.String())
case oDIV:
x, y := vm.stack.Popn()
// floor(x / y)
base.Div(x, y)
// Pop result back on the stack
vm.stack.Push(base.String())
case oSDIV:
x, y := vm.stack.Popn()
// n > 2**255
if x.Cmp(Pow256) > 0 { x.Sub(Pow256, x) }
if y.Cmp(Pow256) > 0 { y.Sub(Pow256, y) }
z := new(big.Int)
z.Div(x, y)
if z.Cmp(Pow256) > 0 { z.Sub(Pow256, z) }
// Push result on to the stack
vm.stack.Push(z.String())
case oMOD:
x, y := vm.stack.Popn()
base.Mod(x, y)
vm.stack.Push(base.String())
case oSMOD:
x, y := vm.stack.Popn()
// n > 2**255
if x.Cmp(Pow256) > 0 { x.Sub(Pow256, x) }
if y.Cmp(Pow256) > 0 { y.Sub(Pow256, y) }
z := new(big.Int)
z.Mod(x, y)
if z.Cmp(Pow256) > 0 { z.Sub(Pow256, z) }
// Push result on to the stack
vm.stack.Push(z.String())
case oEXP:
x, y := vm.stack.Popn()
base.Exp(x, y, Pow256)
vm.stack.Push(base.String())
case oNEG:
base.Sub(Pow256, Big(vm.stack.Pop()))
vm.stack.Push(base.String())
case oLT:
x, y := vm.stack.Popn()
// x < y
if x.Cmp(y) < 0 {
vm.stack.Push("1")
} else {
vm.stack.Push("0")
}
case oLE:
x, y := vm.stack.Popn()
// x <= y
if x.Cmp(y) < 1 {
vm.stack.Push("1")
} else {
vm.stack.Push("0")
}
case oGT:
x, y := vm.stack.Popn()
// x > y
if x.Cmp(y) > 0 {
vm.stack.Push("1")
} else {
vm.stack.Push("0")
}
case oGE:
x, y := vm.stack.Popn()
// x >= y
if x.Cmp(y) > -1 {
vm.stack.Push("1")
} else {
vm.stack.Push("0")
}
case oNOT:
x, y := vm.stack.Popn()
// x != y
if x.Cmp(y) != 0 {
vm.stack.Push("1")
} else {
vm.stack.Push("0")
}
case oMYADDRESS:
vm.stack.Push(string(tx.Hash()))
case oTXSENDER:
vm.stack.Push(tx.sender)
case oPUSH:
// Get the next entry and pushes the value on the stack
pc++
vm.stack.Push(contract.state.Get(string(NumberToBytes(uint64(pc), 32))))
case oPOP:
// Pop current value of the stack
vm.stack.Pop()
case oLOAD:
// Load instruction X on the stack
i, _ := strconv.Atoi(vm.stack.Pop())
vm.stack.Push(contract.state.Get(string(NumberToBytes(uint64(i), 32))))
case oSTOP:
break out
}
pc++
}
vm.stack.Print()
}
|
