package main
import (
"math"
"math/big"
"fmt"
"strconv"
_ "encoding/hex"
)
// Op codes
const (
oSTOP int = 0x00
oADD int = 0x10
oSUB int = 0x11
oMUL int = 0x12
oDIV int = 0x13
oSDIV int = 0x14
oMOD int = 0x15
oSMOD int = 0x16
oEXP int = 0x17
oNEG int = 0x18
oLT int = 0x20
oLE int = 0x21
oGT int = 0x22
oGE int = 0x23
oEQ int = 0x24
oNOT int = 0x25
oSHA256 int = 0x30
oRIPEMD160 int = 0x31
oECMUL int = 0x32
oECADD int = 0x33
oSIGN int = 0x34
oRECOVER int = 0x35
oCOPY int = 0x40
oST int = 0x41
oLD int = 0x42
oSET int = 0x43
oJMP int = 0x50
oJMPI int = 0x51
oIND int = 0x52
oEXTRO int = 0x60
oBALANCE int = 0x61
oMKTX int = 0x70
oDATA int = 0x80
oDATAN int = 0x81
oMYADDRESS int = 0x90
oSUICIDE int = 0xff
)
type OpType int
const (
tNorm = iota
tData
tExtro
tCrypto
)
type TxCallback func(opType OpType) bool
type Vm struct {
// Memory stack
stack map[string]string
// Index ptr
iptr int
memory map[string]map[string]string
}
func NewVm() *Vm {
fmt.Println("init Ethereum VM")
stackSize := uint(256)
fmt.Println("stack size =", stackSize)
return &Vm{make(map[string]string), 0, make(map[string]map[string]string)}
}
func (vm *Vm) RunTransaction(tx *Transaction, cb TxCallback) {
fmt.Printf(`
# processing Tx (%v)
# fee = %f, ops = %d, sender = %s, value = %d
`, tx.addr, float32(tx.fee) / 1e8, len(tx.data), tx.sender, tx.value)
vm.stack = make(map[string]string)
vm.stack["0"] = tx.sender
vm.stack["1"] = "100" //int(tx.value)
vm.stack["1"] = "1000" //int(tx.fee)
//vm.memory[tx.addr] = make([]int, 256)
vm.memory[tx.addr] = make(map[string]string)
// Define instruction 'accessors' for the instruction, which makes it more readable
// also called register values, shorthanded as Rx/y/z. Memory address are shorthanded as Mx/y/z.
// Instructions are shorthanded as Ix/y/z
x := 0; y := 1; z := 2; //a := 3; b := 4; c := 5
out:
for vm.iptr < len(tx.data) {
// 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?
op, args, _ := Instr(tx.data[vm.iptr])
fmt.Printf("%-3d %d %v\n", vm.iptr, op, args)
opType := OpType(tNorm)
// Determine the op type (used for calculating fees by the block manager)
switch op {
case oEXTRO, oBALANCE:
opType = tExtro
case oSHA256, oRIPEMD160, oECMUL, oECADD: // TODO add rest
opType = tCrypto
}
// If the callback yielded a negative result abort execution
if !cb(opType) { break out }
nptr := vm.iptr
switch op {
case oSTOP:
fmt.Println("exiting (oSTOP), idx =", nptr)
break out
case oADD:
// (Rx + Ry) % 2 ** 256
base.Add(Big(vm.stack[args[ x ]]), Big(vm.stack[args[ y ]]))
base.Mod(base, big.NewInt(int64(math.Pow(2, 256))))
// Set the result to Rz
vm.stack[args[ z ]] = base.String()
case oSUB:
// (Rx - Ry) % 2 ** 256
base.Sub(Big(vm.stack[args[ x ]]), Big(vm.stack[args[ y ]]))
base.Mod(base, big.NewInt(int64(math.Pow(2, 256))))
// Set the result to Rz
vm.stack[args[ z ]] = base.String()
case oMUL:
// (Rx * Ry) % 2 ** 256
base.Mul(Big(vm.stack[args[ x ]]), Big(vm.stack[args[ y ]]))
base.Mod(base, big.NewInt(int64(math.Pow(2, 256))))
// Set the result to Rz
vm.stack[args[ z ]] = base.String()
case oDIV:
// floor(Rx / Ry)
base.Div(Big(vm.stack[args[ x ]]), Big(vm.stack[args[ y ]]))
// Set the result to Rz
vm.stack[args[ z ]] = base.String()
case oSET:
// Set the (numeric) value at Iy to Rx
vm.stack[args[ x ]] = args[ y ]
case oLD:
// Load the value at Mx to Ry
vm.stack[args[ y ]] = vm.memory[tx.addr][vm.stack[args[ x ]]]
case oLT:
cmp := Big(vm.stack[args[ x ]]).Cmp( Big(vm.stack[args[ y ]]) )
// Set the result as "boolean" value to Rz
if cmp < 0 { // a < b
vm.stack[args[ z ]] = "1"
} else {
vm.stack[args[ z ]] = "0"
}
case oJMP:
// Set the instruction pointer to the value at Rx
ptr, _ := strconv.Atoi( vm.stack[args[ x ]] )
nptr = ptr
case oJMPI:
// Set the instruction pointer to the value at Ry if Rx yields true
if vm.stack[args[ x ]] != "0" {
ptr, _ := strconv.Atoi( vm.stack[args[ y ]] )
nptr = ptr
}
default:
fmt.Println("Error op", op)
break
}
if vm.iptr == nptr {
vm.iptr++
} else {
vm.iptr = nptr
fmt.Println("... JMP", nptr, "...")
}
}
fmt.Println("# finished processing Tx\n")
}
