path: root/core/vm/vm.go

package vm

import (
    "fmt"
    "math/big"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/core/state"
    "github.com/ethereum/go-ethereum/crypto"
    "github.com/ethereum/go-ethereum/logger/glog"
    "github.com/ethereum/go-ethereum/params"
)

type Vm struct {
    env Environment

    logTy  byte
    logStr string

    err error
    // For logging
    debug bool

    BreakPoints []int64
    Stepping    bool
    Fn          string

    Recoverable bool

    // Will be called before the vm returns
    After func(*Context, error)
}

func New(env Environment) *Vm {
    lt := LogTyPretty

    return &Vm{debug: Debug, env: env, logTy: lt, Recoverable: true}
}

func (self *Vm) Run(context *Context, callData []byte) (ret []byte, err error) {
    self.env.SetDepth(self.env.Depth() + 1)
    defer self.env.SetDepth(self.env.Depth() - 1)

    var (
        caller = context.caller
        code   = context.Code
        value  = context.value
        price  = context.Price
    )

    self.Printf("(%d) (%x) %x (code=%d) gas: %v (d) %x", self.env.Depth(), caller.Address().Bytes()[:4], context.Address(), len(code), context.Gas, callData).Endl()

    // User defer pattern to check for an error and, based on the error being nil or not, use all gas and return.
    defer func() {
        if self.After != nil {
            self.After(context, err)
        }

        if err != nil {
            self.Printf(" %v", err).Endl()
            // In case of a VM exception (known exceptions) all gas consumed (panics NOT included).
            context.UseGas(context.Gas)

            ret = context.Return(nil)
        }
    }()

    if context.CodeAddr != nil {
        if p := Precompiled[context.CodeAddr.Str()]; p != nil {
            return self.RunPrecompiled(p, callData, context)
        }
    }

    var (
        op OpCode

        destinations = analyseJumpDests(context.Code)
        mem          = NewMemory()
        stack        = newStack()
        pc           = new(big.Int)
        statedb      = self.env.State()

        jump = func(from *big.Int, to *big.Int) error {
            nop := context.GetOp(to)
            if !destinations.Has(to) {
                return fmt.Errorf("invalid jump destination (%v) %v", nop, to)
            }

            self.Printf(" ~> %v", to)
            pc = to

            self.Endl()

            return nil
        }
    )

    // Don't bother with the execution if there's no code.
    if len(code) == 0 {
        return context.Return(nil), nil
    }

    for {
        // The base for all big integer arithmetic
        base := new(big.Int)

        // Get the memory location of pc
        op = context.GetOp(pc)

        self.Printf("(pc) %-3d -o- %-14s (m) %-4d (s) %-4d ", pc, op.String(), mem.Len(), stack.len())
        newMemSize, gas, err := self.calculateGasAndSize(context, caller, op, statedb, mem, stack)
        if err != nil {
            return nil, err
        }

        self.Printf("(g) %-3v (%v)", gas, context.Gas)

        if !context.UseGas(gas) {
            self.Endl()

            tmp := new(big.Int).Set(context.Gas)

            context.UseGas(context.Gas)

            return context.Return(nil), OOG(gas, tmp)
        }

        mem.Resize(newMemSize.Uint64())

        switch op {
        // 0x20 range
        case ADD:
            x, y := stack.pop(), stack.pop()
            self.Printf(" %v + %v", y, x)

            base.Add(x, y)

            U256(base)

            self.Printf(" = %v", base)
            // pop result back on the stack
            stack.push(base)
        case SUB:
            x, y := stack.pop(), stack.pop()
            self.Printf(" %v - %v", y, x)

            base.Sub(x, y)

            U256(base)

            self.Printf(" = %v", base)
            // pop result back on the stack
            stack.push(base)
        case MUL:
            x, y := stack.pop(), stack.pop()
            self.Printf(" %v * %v", y, x)

            base.Mul(x, y)

            U256(base)

            self.Printf(" = %v", base)
            // pop result back on the stack
            stack.push(base)
        case DIV:
            x, y := stack.pop(), stack.pop()
            self.Printf(" %v / %v", x, y)

            if y.Cmp(common.Big0) != 0 {
                base.Div(x, y)
            }

            U256(base)

            self.Printf(" = %v", base)
            // pop result back on the stack
            stack.push(base)
        case SDIV:
            x, y := S256(stack.pop()), S256(stack.pop())

            self.Printf(" %v / %v", x, y)

            if y.Cmp(common.Big0) == 0 {
                base.Set(common.Big0)
            } else {
                n := new(big.Int)
                if new(big.Int).Mul(x, y).Cmp(common.Big0) < 0 {
                    n.SetInt64(-1)
                } else {
                    n.SetInt64(1)
                }

                base.Div(x.Abs(x), y.Abs(y)).Mul(base, n)

                U256(base)
            }

            self.Printf(" = %v", base)
            stack.push(base)
        case MOD:
            x, y := stack.pop(), stack.pop()

            self.Printf(" %v %% %v", x, y)

            if y.Cmp(common.Big0) == 0 {
                base.Set(common.Big0)
            } else {
                base.Mod(x, y)
            }

            U256(base)

            self.Printf(" = %v", base)
            stack.push(base)
        case SMOD:
            x, y := S256(stack.pop()), S256(stack.pop())

            self.Printf(" %v %% %v", x, y)

            if y.Cmp(common.Big0) == 0 {
                base.Set(common.Big0)
            } else {
                n := new(big.Int)
                if x.Cmp(common.Big0) < 0 {
                    n.SetInt64(-1)
                } else {
                    n.SetInt64(1)
                }

                base.Mod(x.Abs(x), y.Abs(y)).Mul(base, n)

                U256(base)
            }

            self.Printf(" = %v", base)
            stack.push(base)

        case EXP:
            x, y := stack.pop(), stack.pop()

            self.Printf(" %v ** %v", x, y)

            base.Exp(x, y, Pow256)

            U256(base)

            self.Printf(" = %v", base)

            stack.push(base)
        case SIGNEXTEND:
            back := stack.pop()
            if back.Cmp(big.NewInt(31)) < 0 {
                bit := uint(back.Uint64()*8 + 7)
                num := stack.pop()
                mask := new(big.Int).Lsh(common.Big1, bit)
                mask.Sub(mask, common.Big1)
                if common.BitTest(num, int(bit)) {
                    num.Or(num, mask.Not(mask))
                } else {
                    num.And(num, mask)
                }

                num = U256(num)

                self.Printf(" = %v", num)

                stack.push(num)
            }
        case NOT:
            stack.push(U256(new(big.Int).Not(stack.pop())))
            //base.Sub(Pow256, stack.pop()).Sub(base, common.Big1)
            //base = U256(base)
            //stack.push(base)
        case LT:
            x, y := stack.pop(), stack.pop()
            self.Printf(" %v < %v", x, y)
            // x < y
            if x.Cmp(y) < 0 {
                stack.push(common.BigTrue)
            } else {
                stack.push(common.BigFalse)
            }
        case GT:
            x, y := stack.pop(), stack.pop()
            self.Printf(" %v > %v", x, y)

            // x > y
            if x.Cmp(y) > 0 {
                stack.push(common.BigTrue)
            } else {
                stack.push(common.BigFalse)
            }

        case SLT:
            x, y := S256(stack.pop()), S256(stack.pop())
            self.Printf(" %v < %v", x, y)
            // x < y
            if x.Cmp(S256(y)) < 0 {
                stack.push(common.BigTrue)
            } else {
                stack.push(common.BigFalse)
            }
        case SGT:
            x, y := S256(stack.pop()), S256(stack.pop())
            self.Printf(" %v > %v", x, y)

            // x > y
            if x.Cmp(y) > 0 {
                stack.push(common.BigTrue)
            } else {
                stack.push(common.BigFalse)
            }

        case EQ:
            x, y := stack.pop(), stack.pop()
            self.Printf(" %v == %v", y, x)

            // x == y
            if x.Cmp(y) == 0 {
                stack.push(common.BigTrue)
            } else {
                stack.push(common.BigFalse)
            }
        case ISZERO:
            x := stack.pop()
            if x.Cmp(common.BigFalse) > 0 {
                stack.push(common.BigFalse)
            } else {
                stack.push(common.BigTrue)
            }

            // 0x10 range
        case AND:
            x, y := stack.pop(), stack.pop()
            self.Printf(" %v & %v", y, x)

            stack.push(base.And(x, y))
        case OR:
            x, y := stack.pop(), stack.pop()
            self.Printf(" %v | %v", x, y)

            stack.push(base.Or(x, y))
        case XOR:
            x, y := stack.pop(), stack.pop()
            self.Printf(" %v ^ %v", x, y)

            stack.push(base.Xor(x, y))
        case BYTE:
            th, val := stack.pop(), stack.pop()

            if th.Cmp(big.NewInt(32)) < 0 {
                byt := big.NewInt(int64(common.LeftPadBytes(val.Bytes(), 32)[th.Int64()]))

                base.Set(byt)
            } else {
                base.Set(common.BigFalse)
            }

            self.Printf(" => 0x%x", base.Bytes())

            stack.push(base)
        case ADDMOD:
            x := stack.pop()
            y := stack.pop()
            z := stack.pop()

            if z.Cmp(Zero) > 0 {
                add := new(big.Int).Add(x, y)
                base.Mod(add, z)

                base = U256(base)
            }

            self.Printf(" %v + %v %% %v = %v", x, y, z, base)

            stack.push(base)
        case MULMOD:
            x := stack.pop()
            y := stack.pop()
            z := stack.pop()

            if z.Cmp(Zero) > 0 {
                mul := new(big.Int).Mul(x, y)
                base.Mod(mul, z)

                U256(base)
            }

            self.Printf(" %v + %v %% %v = %v", x, y, z, base)

            stack.push(base)

            // 0x20 range
        case SHA3:
            offset, size := stack.pop(), stack.pop()
            data := crypto.Sha3(mem.Get(offset.Int64(), size.Int64()))

            stack.push(common.BigD(data))

            self.Printf(" => (%v) %x", size, data)
            // 0x30 range
        case ADDRESS:
            stack.push(common.Bytes2Big(context.Address().Bytes()))

            self.Printf(" => %x", context.Address())
        case BALANCE:
            addr := common.BigToAddress(stack.pop())
            balance := statedb.GetBalance(addr)

            stack.push(balance)

            self.Printf(" => %v (%x)", balance, addr)
        case ORIGIN:
            origin := self.env.Origin()

            stack.push(origin.Big())

            self.Printf(" => %x", origin)
        case CALLER:
            caller := context.caller.Address()
            stack.push(common.Bytes2Big(caller.Bytes()))

            self.Printf(" => %x", caller)
        case CALLVALUE:
            stack.push(value)

            self.Printf(" => %v", value)
        case CALLDATALOAD:
            data := getData(callData, stack.pop(), common.Big32)

            self.Printf(" => 0x%x", data)

            stack.push(common.Bytes2Big(data))
        case CALLDATASIZE:
            l := int64(len(callData))
            stack.push(big.NewInt(l))

            self.Printf(" => %d", l)
        case CALLDATACOPY:
            var (
                mOff = stack.pop()
                cOff = stack.pop()
                l    = stack.pop()
            )
            data := getData(callData, cOff, l)

            mem.Set(mOff.Uint64(), l.Uint64(), data)

            self.Printf(" => [%v, %v, %v]", mOff, cOff, l)
        case CODESIZE, EXTCODESIZE:
            var code []byte
            if op == EXTCODESIZE {
                addr := common.BigToAddress(stack.pop())

                code = statedb.GetCode(addr)
            } else {
                code = context.Code
            }

            l := big.NewInt(int64(len(code)))
            stack.push(l)

            self.Printf(" => %d", l)
        case CODECOPY, EXTCODECOPY:
            var code []byte
            if op == EXTCODECOPY {
                addr := common.BigToAddress(stack.pop())
                code = statedb.GetCode(addr)
            } else {
                code = context.Code
            }

            var (
                mOff = stack.pop()
                cOff = stack.pop()
                l    = stack.pop()
            )

            codeCopy := getData(code, cOff, l)

            mem.Set(mOff.Uint64(), l.Uint64(), codeCopy)

            self.Printf(" => [%v, %v, %v] %x", mOff, cOff, l, codeCopy)
        case GASPRICE:
            stack.push(context.Price)

            self.Printf(" => %x", context.Price)

            // 0x40 range
        case BLOCKHASH:
            num := stack.pop()

            n := new(big.Int).Sub(self.env.BlockNumber(), common.Big257)
            if num.Cmp(n) > 0 && num.Cmp(self.env.BlockNumber()) < 0 {
                stack.push(self.env.GetHash(num.Uint64()).Big())
            } else {
                stack.push(common.Big0)
            }

            self.Printf(" => 0x%x", stack.peek().Bytes())
        case COINBASE:
            coinbase := self.env.Coinbase()

            stack.push(coinbase.Big())

            self.Printf(" => 0x%x", coinbase)
        case TIMESTAMP:
            time := self.env.Time()

            stack.push(big.NewInt(time))

            self.Printf(" => 0x%x", time)
        case NUMBER:
            number := self.env.BlockNumber()

            stack.push(U256(number))

            self.Printf(" => 0x%x", number.Bytes())
        case DIFFICULTY:
            difficulty := self.env.Difficulty()

            stack.push(difficulty)

            self.Printf(" => 0x%x", difficulty.Bytes())
        case GASLIMIT:
            self.Printf(" => %v", self.env.GasLimit())

            stack.push(self.env.GasLimit())

            // 0x50 range
        case PUSH1, PUSH2, PUSH3, PUSH4, PUSH5, PUSH6, PUSH7, PUSH8, PUSH9, PUSH10, PUSH11, PUSH12, PUSH13, PUSH14, PUSH15, PUSH16, PUSH17, PUSH18, PUSH19, PUSH20, PUSH21, PUSH22, PUSH23, PUSH24, PUSH25, PUSH26, PUSH27, PUSH28, PUSH29, PUSH30, PUSH31, PUSH32:
            a := big.NewInt(int64(op - PUSH1 + 1))
            byts := getData(code, new(big.Int).Add(pc, big.NewInt(1)), a)
            // push value to stack
            stack.push(common.Bytes2Big(byts))
            pc.Add(pc, a)

            self.Printf(" => 0x%x", byts)
        case POP:
            stack.pop()
        case DUP1, DUP2, DUP3, DUP4, DUP5, DUP6, DUP7, DUP8, DUP9, DUP10, DUP11, DUP12, DUP13, DUP14, DUP15, DUP16:
            n := int(op - DUP1 + 1)
            stack.dup(n)

            self.Printf(" => [%d] 0x%x", n, stack.peek().Bytes())
        case SWAP1, SWAP2, SWAP3, SWAP4, SWAP5, SWAP6, SWAP7, SWAP8, SWAP9, SWAP10, SWAP11, SWAP12, SWAP13, SWAP14, SWAP15, SWAP16:
            n := int(op - SWAP1 + 2)
            stack.swap(n)

            self.Printf(" => [%d]", n)
        case LOG0, LOG1, LOG2, LOG3, LOG4:
            n := int(op - LOG0)
            topics := make([]common.Hash, n)
            mStart, mSize := stack.pop(), stack.pop()
            for i := 0; i < n; i++ {
                topics[i] = common.BigToHash(stack.pop()) //common.LeftPadBytes(stack.pop().Bytes(), 32)
            }

            data := mem.Get(mStart.Int64(), mSize.Int64())
            log := state.NewLog(context.Address(), topics, data, self.env.BlockNumber().Uint64())
            //log := &Log{context.Address(), topics, data, self.env.BlockNumber().Uint64()}
            self.env.AddLog(log)

            self.Printf(" => %v", log)
        case MLOAD:
            offset := stack.pop()
            val := common.BigD(mem.Get(offset.Int64(), 32))
            stack.push(val)

            self.Printf(" => 0x%x", val.Bytes())
        case MSTORE: // Store the value at stack top-1 in to memory at location stack top
            // pop value of the stack
            mStart, val := stack.pop(), stack.pop()
            mem.Set(mStart.Uint64(), 32, common.BigToBytes(val, 256))

            self.Printf(" => 0x%x", val)
        case MSTORE8:
            off, val := stack.pop().Int64(), stack.pop().Int64()

            mem.store[off] = byte(val & 0xff)

            self.Printf(" => [%v] 0x%x", off, mem.store[off])
        case SLOAD:
            loc := common.BigToHash(stack.pop())
            val := common.Bytes2Big(statedb.GetState(context.Address(), loc))
            stack.push(val)

            self.Printf(" {0x%x : 0x%x}", loc, val.Bytes())
        case SSTORE:
            loc := common.BigToHash(stack.pop())
            val := stack.pop()

            statedb.SetState(context.Address(), loc, val)

            self.Printf(" {0x%x : 0x%x}", loc, val.Bytes())
        case JUMP:
            if err := jump(pc, stack.pop()); err != nil {
                return nil, err
            }

            continue
        case JUMPI:
            pos, cond := stack.pop(), stack.pop()

            if cond.Cmp(common.BigTrue) >= 0 {
                if err := jump(pc, pos); err != nil {
                    return nil, err
                }

                continue
            }

            self.Printf(" ~> false")

        case JUMPDEST:
        case PC:
            //stack.push(big.NewInt(int64(pc)))
            stack.push(pc)
        case MSIZE:
            stack.push(big.NewInt(int64(mem.Len())))
        case GAS:
            stack.push(context.Gas)

            self.Printf(" => %x", context.Gas)
            // 0x60 range
        case CREATE:

            var (
                value        = stack.pop()
                offset, size = stack.pop(), stack.pop()
                input        = mem.Get(offset.Int64(), size.Int64())
                gas          = new(big.Int).Set(context.Gas)
                addr         common.Address
            )
            self.Endl()

            context.UseGas(context.Gas)
            ret, suberr, ref := self.env.Create(context, input, gas, price, value)
            if suberr != nil {
                stack.push(common.BigFalse)

                self.Printf(" (*) 0x0 %v", suberr)
            } else {
                // gas < len(ret) * CreateDataGas == NO_CODE
                dataGas := big.NewInt(int64(len(ret)))
                dataGas.Mul(dataGas, params.CreateDataGas)
                if context.UseGas(dataGas) {
                    ref.SetCode(ret)
                }
                addr = ref.Address()

                stack.push(addr.Big())

            }

        case CALL, CALLCODE:
            gas := stack.pop()
            // pop gas and value of the stack.
            addr, value := stack.pop(), stack.pop()
            value = U256(value)
            // pop input size and offset
            inOffset, inSize := stack.pop(), stack.pop()
            // pop return size and offset
            retOffset, retSize := stack.pop(), stack.pop()

            address := common.BigToAddress(addr)
            self.Printf(" => %x", address).Endl()

            // Get the arguments from the memory
            args := mem.Get(inOffset.Int64(), inSize.Int64())

            if len(value.Bytes()) > 0 {
                gas.Add(gas, params.CallStipend)
            }

            var (
                ret []byte
                err error
            )
            if op == CALLCODE {
                ret, err = self.env.CallCode(context, address, args, gas, price, value)
            } else {
                ret, err = self.env.Call(context, address, args, gas, price, value)
            }

            if err != nil {
                stack.push(common.BigFalse)

                self.Printf("%v").Endl()
            } else {
                stack.push(common.BigTrue)

                mem.Set(retOffset.Uint64(), retSize.Uint64(), ret)
            }
            self.Printf("resume %x (%v)", context.Address(), context.Gas)
        case RETURN:
            offset, size := stack.pop(), stack.pop()
            ret := mem.GetPtr(offset.Int64(), size.Int64())

            self.Printf(" => [%v, %v] (%d) 0x%x", offset, size, len(ret), ret).Endl()

            return context.Return(ret), nil
        case SUICIDE:
            receiver := statedb.GetOrNewStateObject(common.BigToAddress(stack.pop()))
            balance := statedb.GetBalance(context.Address())

            self.Printf(" => (%x) %v", receiver.Address().Bytes()[:4], balance)

            receiver.AddBalance(balance)

            statedb.Delete(context.Address())

            fallthrough
        case STOP: // Stop the context
            self.Endl()

            return context.Return(nil), nil
        default:
            self.Printf("(pc) %-3v Invalid opcode %x\n", pc, op).Endl()

            return nil, fmt.Errorf("Invalid opcode %x", op)
        }

        pc.Add(pc, One)

        self.Endl()
    }
}

func (self *Vm) calculateGasAndSize(context *Context, caller ContextRef, op OpCode, statedb *state.StateDB, mem *Memory, stack *stack) (*big.Int, *big.Int, error) {
    var (
        gas                 = new(big.Int)
        newMemSize *big.Int = new(big.Int)
    )
    err := baseCheck(op, stack, gas)
    if err != nil {
        return nil, nil, err
    }

    // stack Check, memory resize & gas phase
    switch op {
    case SWAP1, SWAP2, SWAP3, SWAP4, SWAP5, SWAP6, SWAP7, SWAP8, SWAP9, SWAP10, SWAP11, SWAP12, SWAP13, SWAP14, SWAP15, SWAP16:
        n := int(op - SWAP1 + 2)
        err := stack.require(n)
        if err != nil {
            return nil, nil, err
        }
        gas.Set(GasFastestStep)
    case DUP1, DUP2, DUP3, DUP4, DUP5, DUP6, DUP7, DUP8, DUP9, DUP10, DUP11, DUP12, DUP13, DUP14, DUP15, DUP16:
        n := int(op - DUP1 + 1)
        err := stack.require(n)
        if err != nil {
            return nil, nil, err
        }
        gas.Set(GasFastestStep)
    case LOG0, LOG1, LOG2, LOG3, LOG4:
        n := int(op - LOG0)
        err := stack.require(n + 2)
        if err != nil {
            return nil, nil, err
        }

        mSize, mStart := stack.data[stack.len()-2], stack.data[stack.len()-1]

        gas.Add(gas, params.LogGas)
        gas.Add(gas, new(big.Int).Mul(big.NewInt(int64(n)), params.LogTopicGas))
        gas.Add(gas, new(big.Int).Mul(mSize, params.LogDataGas))

        newMemSize = calcMemSize(mStart, mSize)
    case EXP:
        gas.Add(gas, new(big.Int).Mul(big.NewInt(int64(len(stack.data[stack.len()-2].Bytes()))), params.ExpByteGas))
    case SSTORE:
        err := stack.require(2)
        if err != nil {
            return nil, nil, err
        }

        var g *big.Int
        y, x := stack.data[stack.len()-2], stack.data[stack.len()-1]
        val := statedb.GetState(context.Address(), common.BigToHash(x))
        if len(val) == 0 && len(y.Bytes()) > 0 {
            // 0 => non 0
            g = params.SstoreSetGas
        } else if len(val) > 0 && len(y.Bytes()) == 0 {
            statedb.Refund(self.env.Origin(), params.SstoreRefundGas)

            g = params.SstoreClearGas
        } else {
            // non 0 => non 0 (or 0 => 0)
            g = params.SstoreClearGas
        }
        gas.Set(g)
    case SUICIDE:
        if !statedb.IsDeleted(context.Address()) {
            statedb.Refund(self.env.Origin(), params.SuicideRefundGas)
        }
    case MLOAD:
        newMemSize = calcMemSize(stack.peek(), u256(32))
    case MSTORE8:
        newMemSize = calcMemSize(stack.peek(), u256(1))
    case MSTORE:
        newMemSize = calcMemSize(stack.peek(), u256(32))
    case RETURN:
        newMemSize = calcMemSize(stack.peek(), stack.data[stack.len()-2])
    case SHA3:
        newMemSize = calcMemSize(stack.peek(), stack.data[stack.len()-2])

        words := toWordSize(stack.data[stack.len()-2])
        gas.Add(gas, words.Mul(words, params.Sha3WordGas))
    case CALLDATACOPY:
        newMemSize = calcMemSize(stack.peek(), stack.data[stack.len()-3])

        words := toWordSize(stack.data[stack.len()-3])
        gas.Add(gas, words.Mul(words, params.CopyGas))
    case CODECOPY:
        newMemSize = calcMemSize(stack.peek(), stack.data[stack.len()-3])

        words := toWordSize(stack.data[stack.len()-3])
        gas.Add(gas, words.Mul(words, params.CopyGas))
    case EXTCODECOPY:
        newMemSize = calcMemSize(stack.data[stack.len()-2], stack.data[stack.len()-4])

        words := toWordSize(stack.data[stack.len()-4])
        gas.Add(gas, words.Mul(words, params.CopyGas))

    case CREATE:
        newMemSize = calcMemSize(stack.data[stack.len()-2], stack.data[stack.len()-3])
    case CALL, CALLCODE:
        gas.Add(gas, stack.data[stack.len()-1])

        if op == CALL {
            if self.env.State().GetStateObject(common.BigToAddress(stack.data[stack.len()-2])) == nil {
                gas.Add(gas, params.CallNewAccountGas)
            }
        }

        if len(stack.data[stack.len()-3].Bytes()) > 0 {
            gas.Add(gas, params.CallValueTransferGas)
        }

        x := calcMemSize(stack.data[stack.len()-6], stack.data[stack.len()-7])
        y := calcMemSize(stack.data[stack.len()-4], stack.data[stack.len()-5])

        newMemSize = common.BigMax(x, y)
    }

    if newMemSize.Cmp(common.Big0) > 0 {
        newMemSizeWords := toWordSize(newMemSize)
        newMemSize.Mul(newMemSizeWords, u256(32))

        if newMemSize.Cmp(u256(int64(mem.Len()))) > 0 {
            oldSize := toWordSize(big.NewInt(int64(mem.Len())))
            pow := new(big.Int).Exp(oldSize, common.Big2, Zero)
            linCoef := new(big.Int).Mul(oldSize, params.MemoryGas)
            quadCoef := new(big.Int).Div(pow, params.QuadCoeffDiv)
            oldTotalFee := new(big.Int).Add(linCoef, quadCoef)

            pow.Exp(newMemSizeWords, common.Big2, Zero)
            linCoef = new(big.Int).Mul(newMemSizeWords, params.MemoryGas)
            quadCoef = new(big.Int).Div(pow, params.QuadCoeffDiv)
            newTotalFee := new(big.Int).Add(linCoef, quadCoef)

            fee := new(big.Int).Sub(newTotalFee, oldTotalFee)
            gas.Add(gas, fee)
        }
    }

    return newMemSize, gas, nil
}

func (self *Vm) RunPrecompiled(p *PrecompiledAccount, callData []byte, context *Context) (ret []byte, err error) {
    gas := p.Gas(len(callData))
    if context.UseGas(gas) {
        ret = p.Call(callData)
        self.Printf("NATIVE_FUNC => %x", ret)
        self.Endl()

        return context.Return(ret), nil
    } else {
        self.Printf("NATIVE_FUNC => failed").Endl()

        tmp := new(big.Int).Set(context.Gas)

        return nil, OOG(gas, tmp)
    }
}

func (self *Vm) Printf(format string, v ...interface{}) VirtualMachine {
    if self.debug {
        self.logStr += fmt.Sprintf(format, v...)
    }

    return self
}

func (self *Vm) Endl() VirtualMachine {
    if self.debug {
        glog.V(0).Infoln(self.logStr)
        self.logStr = ""
    }

    return self
}

func (self *Vm) Env() Environment {
    return self.env
}