path: root/core/vm/instructions.go

// Copyright 2015 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package vm

import (
    "errors"
    "fmt"
    "math/big"

    "github.com/dexon-foundation/dexon/common"
    "github.com/dexon-foundation/dexon/common/math"
    "github.com/dexon-foundation/dexon/core/types"
    "github.com/dexon-foundation/dexon/params"
    "golang.org/x/crypto/sha3"
)

var (
    bigZero                  = new(big.Int)
    tt255                    = math.BigPow(2, 255)
    errWriteProtection       = errors.New("evm: write protection")
    errReturnDataOutOfBounds = errors.New("evm: return data out of bounds")
    errExecutionReverted     = errors.New("evm: execution reverted")
    errMaxCodeSizeExceeded   = errors.New("evm: max code size exceeded")
)

func opAdd(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    x, y := stack.pop(), stack.peek()
    math.U256(y.Add(x, y))

    interpreter.intPool.put(x)
    return nil, nil
}

func opSub(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    x, y := stack.pop(), stack.peek()
    math.U256(y.Sub(x, y))

    interpreter.intPool.put(x)
    return nil, nil
}

func opMul(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    x, y := stack.pop(), stack.pop()
    stack.push(math.U256(x.Mul(x, y)))

    interpreter.intPool.put(y)

    return nil, nil
}

func opDiv(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    x, y := stack.pop(), stack.peek()
    if y.Sign() != 0 {
        math.U256(y.Div(x, y))
    } else {
        y.SetUint64(0)
    }
    interpreter.intPool.put(x)
    return nil, nil
}

func opSdiv(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    x, y := math.S256(stack.pop()), math.S256(stack.pop())
    res := interpreter.intPool.getZero()

    if y.Sign() == 0 || x.Sign() == 0 {
        stack.push(res)
    } else {
        if x.Sign() != y.Sign() {
            res.Div(x.Abs(x), y.Abs(y))
            res.Neg(res)
        } else {
            res.Div(x.Abs(x), y.Abs(y))
        }
        stack.push(math.U256(res))
    }
    interpreter.intPool.put(x, y)
    return nil, nil
}

func opMod(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    x, y := stack.pop(), stack.pop()
    if y.Sign() == 0 {
        stack.push(x.SetUint64(0))
    } else {
        stack.push(math.U256(x.Mod(x, y)))
    }
    interpreter.intPool.put(y)
    return nil, nil
}

func opSmod(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    x, y := math.S256(stack.pop()), math.S256(stack.pop())
    res := interpreter.intPool.getZero()

    if y.Sign() == 0 {
        stack.push(res)
    } else {
        if x.Sign() < 0 {
            res.Mod(x.Abs(x), y.Abs(y))
            res.Neg(res)
        } else {
            res.Mod(x.Abs(x), y.Abs(y))
        }
        stack.push(math.U256(res))
    }
    interpreter.intPool.put(x, y)
    return nil, nil
}

func opExp(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    base, exponent := stack.pop(), stack.pop()
    // some shortcuts
    cmpToOne := exponent.Cmp(big1)
    if cmpToOne < 0 { // Exponent is zero
        // x ^ 0 == 1
        stack.push(base.SetUint64(1))
    } else if base.Sign() == 0 {
        // 0 ^ y, if y != 0, == 0
        stack.push(base.SetUint64(0))
    } else if cmpToOne == 0 { // Exponent is one
        // x ^ 1 == x
        stack.push(base)
    } else {
        stack.push(math.Exp(base, exponent))
        interpreter.intPool.put(base)
    }
    interpreter.intPool.put(exponent)
    return nil, nil
}

func opSignExtend(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    back := stack.pop()
    if back.Cmp(big.NewInt(31)) < 0 {
        bit := uint(back.Uint64()*8 + 7)
        num := stack.pop()
        mask := back.Lsh(common.Big1, bit)
        mask.Sub(mask, common.Big1)
        if num.Bit(int(bit)) > 0 {
            num.Or(num, mask.Not(mask))
        } else {
            num.And(num, mask)
        }

        stack.push(math.U256(num))
    }

    interpreter.intPool.put(back)
    return nil, nil
}

func opNot(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    x := stack.peek()
    math.U256(x.Not(x))
    return nil, nil
}

func opLt(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    x, y := stack.pop(), stack.peek()
    if x.Cmp(y) < 0 {
        y.SetUint64(1)
    } else {
        y.SetUint64(0)
    }
    interpreter.intPool.put(x)
    return nil, nil
}

func opGt(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    x, y := stack.pop(), stack.peek()
    if x.Cmp(y) > 0 {
        y.SetUint64(1)
    } else {
        y.SetUint64(0)
    }
    interpreter.intPool.put(x)
    return nil, nil
}

func opSlt(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    x, y := stack.pop(), stack.peek()

    xSign := x.Cmp(tt255)
    ySign := y.Cmp(tt255)

    switch {
    case xSign >= 0 && ySign < 0:
        y.SetUint64(1)

    case xSign < 0 && ySign >= 0:
        y.SetUint64(0)

    default:
        if x.Cmp(y) < 0 {
            y.SetUint64(1)
        } else {
            y.SetUint64(0)
        }
    }
    interpreter.intPool.put(x)
    return nil, nil
}

func opSgt(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    x, y := stack.pop(), stack.peek()

    xSign := x.Cmp(tt255)
    ySign := y.Cmp(tt255)

    switch {
    case xSign >= 0 && ySign < 0:
        y.SetUint64(0)

    case xSign < 0 && ySign >= 0:
        y.SetUint64(1)

    default:
        if x.Cmp(y) > 0 {
            y.SetUint64(1)
        } else {
            y.SetUint64(0)
        }
    }
    interpreter.intPool.put(x)
    return nil, nil
}

func opEq(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    x, y := stack.pop(), stack.peek()
    if x.Cmp(y) == 0 {
        y.SetUint64(1)
    } else {
        y.SetUint64(0)
    }
    interpreter.intPool.put(x)
    return nil, nil
}

func opIszero(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    x := stack.peek()
    if x.Sign() > 0 {
        x.SetUint64(0)
    } else {
        x.SetUint64(1)
    }
    return nil, nil
}

func opAnd(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    x, y := stack.pop(), stack.pop()
    stack.push(x.And(x, y))

    interpreter.intPool.put(y)
    return nil, nil
}

func opOr(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    x, y := stack.pop(), stack.peek()
    y.Or(x, y)

    interpreter.intPool.put(x)
    return nil, nil
}

func opXor(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    x, y := stack.pop(), stack.peek()
    y.Xor(x, y)

    interpreter.intPool.put(x)
    return nil, nil
}

func opByte(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    th, val := stack.pop(), stack.peek()
    if th.Cmp(common.Big32) < 0 {
        b := math.Byte(val, 32, int(th.Int64()))
        val.SetUint64(uint64(b))
    } else {
        val.SetUint64(0)
    }
    interpreter.intPool.put(th)
    return nil, nil
}

func opAddmod(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    x, y, z := stack.pop(), stack.pop(), stack.pop()
    if z.Cmp(bigZero) > 0 {
        x.Add(x, y)
        x.Mod(x, z)
        stack.push(math.U256(x))
    } else {
        stack.push(x.SetUint64(0))
    }
    interpreter.intPool.put(y, z)
    return nil, nil
}

func opMulmod(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    x, y, z := stack.pop(), stack.pop(), stack.pop()
    if z.Cmp(bigZero) > 0 {
        x.Mul(x, y)
        x.Mod(x, z)
        stack.push(math.U256(x))
    } else {
        stack.push(x.SetUint64(0))
    }
    interpreter.intPool.put(y, z)
    return nil, nil
}

// opSHL implements Shift Left
// The SHL instruction (shift left) pops 2 values from the stack, first arg1 and then arg2,
// and pushes on the stack arg2 shifted to the left by arg1 number of bits.
func opSHL(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    // Note, second operand is left in the stack; accumulate result into it, and no need to push it afterwards
    shift, value := math.U256(stack.pop()), math.U256(stack.peek())
    defer interpreter.intPool.put(shift) // First operand back into the pool

    if shift.Cmp(common.Big256) >= 0 {
        value.SetUint64(0)
        return nil, nil
    }
    n := uint(shift.Uint64())
    math.U256(value.Lsh(value, n))

    return nil, nil
}

// opSHR implements Logical Shift Right
// The SHR instruction (logical shift right) pops 2 values from the stack, first arg1 and then arg2,
// and pushes on the stack arg2 shifted to the right by arg1 number of bits with zero fill.
func opSHR(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    // Note, second operand is left in the stack; accumulate result into it, and no need to push it afterwards
    shift, value := math.U256(stack.pop()), math.U256(stack.peek())
    defer interpreter.intPool.put(shift) // First operand back into the pool

    if shift.Cmp(common.Big256) >= 0 {
        value.SetUint64(0)
        return nil, nil
    }
    n := uint(shift.Uint64())
    math.U256(value.Rsh(value, n))

    return nil, nil
}

// opSAR implements Arithmetic Shift Right
// The SAR instruction (arithmetic shift right) pops 2 values from the stack, first arg1 and then arg2,
// and pushes on the stack arg2 shifted to the right by arg1 number of bits with sign extension.
func opSAR(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    // Note, S256 returns (potentially) a new bigint, so we're popping, not peeking this one
    shift, value := math.U256(stack.pop()), math.S256(stack.pop())
    defer interpreter.intPool.put(shift) // First operand back into the pool

    if shift.Cmp(common.Big256) >= 0 {
        if value.Sign() >= 0 {
            value.SetUint64(0)
        } else {
            value.SetInt64(-1)
        }
        stack.push(math.U256(value))
        return nil, nil
    }
    n := uint(shift.Uint64())
    value.Rsh(value, n)
    stack.push(math.U256(value))

    return nil, nil
}

func opSha3(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    offset, size := stack.pop(), stack.pop()
    data := memory.Get(offset.Int64(), size.Int64())

    if interpreter.hasher == nil {
        interpreter.hasher = sha3.NewLegacyKeccak256().(keccakState)
    } else {
        interpreter.hasher.Reset()
    }
    interpreter.hasher.Write(data)
    interpreter.hasher.Read(interpreter.hasherBuf[:])

    evm := interpreter.evm
    if evm.vmConfig.EnablePreimageRecording {
        evm.StateDB.AddPreimage(interpreter.hasherBuf, data)
    }
    stack.push(interpreter.intPool.get().SetBytes(interpreter.hasherBuf[:]))

    interpreter.intPool.put(offset, size)
    return nil, nil
}

func opAddress(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    stack.push(contract.Address().Big())
    return nil, nil
}

func opBalance(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    slot := stack.peek()
    slot.Set(interpreter.evm.StateDB.GetBalance(common.BigToAddress(slot)))
    return nil, nil
}

func opOrigin(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    stack.push(interpreter.evm.Origin.Big())
    return nil, nil
}

func opCaller(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    stack.push(contract.Caller().Big())
    return nil, nil
}

func opCallValue(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    stack.push(interpreter.intPool.get().Set(contract.value))
    return nil, nil
}

func opCallDataLoad(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    stack.push(interpreter.intPool.get().SetBytes(getDataBig(contract.Input, stack.pop(), big32)))
    return nil, nil
}

func opCallDataSize(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    stack.push(interpreter.intPool.get().SetInt64(int64(len(contract.Input))))
    return nil, nil
}

func opCallDataCopy(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    var (
        memOffset  = stack.pop()
        dataOffset = stack.pop()
        length     = stack.pop()
    )
    memory.Set(memOffset.Uint64(), length.Uint64(), getDataBig(contract.Input, dataOffset, length))

    interpreter.intPool.put(memOffset, dataOffset, length)
    return nil, nil
}

func opReturnDataSize(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    stack.push(interpreter.intPool.get().SetUint64(uint64(len(interpreter.returnData))))
    return nil, nil
}

func opReturnDataCopy(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    var (
        memOffset  = stack.pop()
        dataOffset = stack.pop()
        length     = stack.pop()

        end = interpreter.intPool.get().Add(dataOffset, length)
    )
    defer interpreter.intPool.put(memOffset, dataOffset, length, end)

    if end.BitLen() > 64 || uint64(len(interpreter.returnData)) < end.Uint64() {
        return nil, errReturnDataOutOfBounds
    }
    memory.Set(memOffset.Uint64(), length.Uint64(), interpreter.returnData[dataOffset.Uint64():end.Uint64()])

    return nil, nil
}

func opExtCodeSize(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    slot := stack.peek()
    slot.SetUint64(uint64(interpreter.evm.StateDB.GetCodeSize(common.BigToAddress(slot))))

    return nil, nil
}

func opCodeSize(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    l := interpreter.intPool.get().SetInt64(int64(len(contract.Code)))
    stack.push(l)

    return nil, nil
}

func opCodeCopy(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    var (
        memOffset  = stack.pop()
        codeOffset = stack.pop()
        length     = stack.pop()
    )
    codeCopy := getDataBig(contract.Code, codeOffset, length)
    memory.Set(memOffset.Uint64(), length.Uint64(), codeCopy)

    interpreter.intPool.put(memOffset, codeOffset, length)
    return nil, nil
}

func opExtCodeCopy(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    var (
        addr       = common.BigToAddress(stack.pop())
        memOffset  = stack.pop()
        codeOffset = stack.pop()
        length     = stack.pop()
    )
    codeCopy := getDataBig(interpreter.evm.StateDB.GetCode(addr), codeOffset, length)
    memory.Set(memOffset.Uint64(), length.Uint64(), codeCopy)

    interpreter.intPool.put(memOffset, codeOffset, length)
    return nil, nil
}

// opExtCodeHash returns the code hash of a specified account.
// There are several cases when the function is called, while we can relay everything
// to `state.GetCodeHash` function to ensure the correctness.
//   (1) Caller tries to get the code hash of a normal contract account, state
// should return the relative code hash and set it as the result.
//
//   (2) Caller tries to get the code hash of a non-existent account, state should
// return common.Hash{} and zero will be set as the result.
//
//   (3) Caller tries to get the code hash for an account without contract code,
// state should return emptyCodeHash(0xc5d246...) as the result.
//
//   (4) Caller tries to get the code hash of a precompiled account, the result
// should be zero or emptyCodeHash.
//
// It is worth noting that in order to avoid unnecessary create and clean,
// all precompile accounts on mainnet have been transferred 1 wei, so the return
// here should be emptyCodeHash.
// If the precompile account is not transferred any amount on a private or
// customized chain, the return value will be zero.
//
//   (5) Caller tries to get the code hash for an account which is marked as suicided
// in the current transaction, the code hash of this account should be returned.
//
//   (6) Caller tries to get the code hash for an account which is marked as deleted,
// this account should be regarded as a non-existent account and zero should be returned.
func opExtCodeHash(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    slot := stack.peek()
    address := common.BigToAddress(slot)
    if interpreter.evm.StateDB.Empty(address) {
        slot.SetUint64(0)
    } else {
        slot.SetBytes(interpreter.evm.StateDB.GetCodeHash(address).Bytes())
    }
    return nil, nil
}

func opGasprice(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    stack.push(interpreter.intPool.get().Set(interpreter.evm.GasPrice))
    return nil, nil
}

func opBlockhash(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    num := stack.pop()

    n := interpreter.intPool.get().Sub(interpreter.evm.BlockNumber, common.Big257)
    if num.Cmp(n) > 0 && num.Cmp(interpreter.evm.BlockNumber) < 0 {
        stack.push(interpreter.evm.GetHash(num.Uint64()).Big())
    } else {
        stack.push(interpreter.intPool.getZero())
    }
    interpreter.intPool.put(num, n)
    return nil, nil
}

func opCoinbase(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    stack.push(interpreter.evm.Coinbase.Big())
    return nil, nil
}

func opTimestamp(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    stack.push(math.U256(interpreter.intPool.get().Set(interpreter.evm.Time)))
    return nil, nil
}

func opNumber(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    stack.push(math.U256(interpreter.intPool.get().Set(interpreter.evm.BlockNumber)))
    return nil, nil
}

func opDifficulty(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    stack.push(math.U256(interpreter.intPool.get().Set(interpreter.evm.Difficulty)))
    return nil, nil
}

func opGasLimit(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    stack.push(math.U256(interpreter.intPool.get().SetUint64(interpreter.evm.GasLimit)))
    return nil, nil
}

func opPop(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    interpreter.intPool.put(stack.pop())
    return nil, nil
}

func opMload(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    offset := stack.pop()
    val := interpreter.intPool.get().SetBytes(memory.Get(offset.Int64(), 32))
    stack.push(val)

    interpreter.intPool.put(offset)
    return nil, nil
}

func opMstore(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    // pop value of the stack
    mStart, val := stack.pop(), stack.pop()
    memory.Set32(mStart.Uint64(), val)

    interpreter.intPool.put(mStart, val)
    return nil, nil
}

func opMstore8(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    off, val := stack.pop().Int64(), stack.pop().Int64()
    memory.store[off] = byte(val & 0xff)

    return nil, nil
}

func opSload(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    loc := stack.peek()
    val := interpreter.evm.StateDB.GetState(contract.Address(), common.BigToHash(loc))
    loc.SetBytes(val.Bytes())
    return nil, nil
}

func opSstore(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    loc := common.BigToHash(stack.pop())
    val := stack.pop()
    interpreter.evm.StateDB.SetState(contract.Address(), loc, common.BigToHash(val))

    interpreter.intPool.put(val)
    return nil, nil
}

func opJump(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    pos := stack.pop()
    if !contract.validJumpdest(pos) {
        nop := contract.GetOp(pos.Uint64())
        return nil, fmt.Errorf("invalid jump destination (%v) %v", nop, pos)
    }
    *pc = pos.Uint64()

    interpreter.intPool.put(pos)
    return nil, nil
}

func opJumpi(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    pos, cond := stack.pop(), stack.pop()
    if cond.Sign() != 0 {
        if !contract.validJumpdest(pos) {
            nop := contract.GetOp(pos.Uint64())
            return nil, fmt.Errorf("invalid jump destination (%v) %v", nop, pos)
        }
        *pc = pos.Uint64()
    } else {
        *pc++
    }

    interpreter.intPool.put(pos, cond)
    return nil, nil
}

func opJumpdest(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    return nil, nil
}

func opPc(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    stack.push(interpreter.intPool.get().SetUint64(*pc))
    return nil, nil
}

func opMsize(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    stack.push(interpreter.intPool.get().SetInt64(int64(memory.Len())))
    return nil, nil
}

func opGas(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    stack.push(interpreter.intPool.get().SetUint64(contract.Gas))
    return nil, nil
}

func opCreate(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    var (
        value        = stack.pop()
        offset, size = stack.pop(), stack.pop()
        input        = memory.Get(offset.Int64(), size.Int64())
        gas          = contract.Gas
    )
    if interpreter.evm.ChainConfig().IsEIP150(interpreter.evm.BlockNumber) {
        gas -= gas / 64
    }

    contract.UseGas(gas)
    res, addr, returnGas, suberr := interpreter.evm.Create(contract, input, gas, value)
    // Push item on the stack based on the returned error. If the ruleset is
    // homestead we must check for CodeStoreOutOfGasError (homestead only
    // rule) and treat as an error, if the ruleset is frontier we must
    // ignore this error and pretend the operation was successful.
    if interpreter.evm.ChainConfig().IsHomestead(interpreter.evm.BlockNumber) && suberr == ErrCodeStoreOutOfGas {
        stack.push(interpreter.intPool.getZero())
    } else if suberr != nil && suberr != ErrCodeStoreOutOfGas {
        stack.push(interpreter.intPool.getZero())
    } else {
        stack.push(addr.Big())
    }
    contract.Gas += returnGas
    interpreter.intPool.put(value, offset, size)

    if suberr == errExecutionReverted {
        return res, nil
    }
    return nil, nil
}

func opCreate2(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    var (
        endowment    = stack.pop()
        offset, size = stack.pop(), stack.pop()
        salt         = stack.pop()
        input        = memory.Get(offset.Int64(), size.Int64())
        gas          = contract.Gas
    )

    // Apply EIP150
    gas -= gas / 64
    contract.UseGas(gas)
    res, addr, returnGas, suberr := interpreter.evm.Create2(contract, input, gas, endowment, salt)
    // Push item on the stack based on the returned error.
    if suberr != nil {
        stack.push(interpreter.intPool.getZero())
    } else {
        stack.push(addr.Big())
    }
    contract.Gas += returnGas
    interpreter.intPool.put(endowment, offset, size, salt)

    if suberr == errExecutionReverted {
        return res, nil
    }
    return nil, nil
}

func opCall(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    // Pop gas. The actual gas in interpreter.evm.callGasTemp.
    interpreter.intPool.put(stack.pop())
    gas := interpreter.evm.callGasTemp
    // Pop other call parameters.
    addr, value, inOffset, inSize, retOffset, retSize := stack.pop(), stack.pop(), stack.pop(), stack.pop(), stack.pop(), stack.pop()
    toAddr := common.BigToAddress(addr)
    value = math.U256(value)
    // Get the arguments from the memory.
    args := memory.Get(inOffset.Int64(), inSize.Int64())

    if value.Sign() != 0 {
        gas += params.CallStipend
    }
    ret, returnGas, err := interpreter.evm.Call(contract, toAddr, args, gas, value)
    if err != nil {
        stack.push(interpreter.intPool.getZero())
    } else {
        stack.push(interpreter.intPool.get().SetUint64(1))
    }
    if err == nil || err == errExecutionReverted {
        memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
    }
    contract.Gas += returnGas

    interpreter.intPool.put(addr, value, inOffset, inSize, retOffset, retSize)
    return ret, nil
}

func opCallCode(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    // Pop gas. The actual gas is in interpreter.evm.callGasTemp.
    interpreter.intPool.put(stack.pop())
    gas := interpreter.evm.callGasTemp
    // Pop other call parameters.
    addr, value, inOffset, inSize, retOffset, retSize := stack.pop(), stack.pop(), stack.pop(), stack.pop(), stack.pop(), stack.pop()
    toAddr := common.BigToAddress(addr)
    value = math.U256(value)
    // Get arguments from the memory.
    args := memory.Get(inOffset.Int64(), inSize.Int64())

    if value.Sign() != 0 {
        gas += params.CallStipend
    }
    ret, returnGas, err := interpreter.evm.CallCode(contract, toAddr, args, gas, value)
    if err != nil {
        stack.push(interpreter.intPool.getZero())
    } else {
        stack.push(interpreter.intPool.get().SetUint64(1))
    }
    if err == nil || err == errExecutionReverted {
        memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
    }
    contract.Gas += returnGas

    interpreter.intPool.put(addr, value, inOffset, inSize, retOffset, retSize)
    return ret, nil
}

func opDelegateCall(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    // Pop gas. The actual gas is in interpreter.evm.callGasTemp.
    interpreter.intPool.put(stack.pop())
    gas := interpreter.evm.callGasTemp
    // Pop other call parameters.
    addr, inOffset, inSize, retOffset, retSize := stack.pop(), stack.pop(), stack.pop(), stack.pop(), stack.pop()
    toAddr := common.BigToAddress(addr)
    // Get arguments from the memory.
    args := memory.Get(inOffset.Int64(), inSize.Int64())

    ret, returnGas, err := interpreter.evm.DelegateCall(contract, toAddr, args, gas)
    if err != nil {
        stack.push(interpreter.intPool.getZero())
    } else {
        stack.push(interpreter.intPool.get().SetUint64(1))
    }
    if err == nil || err == errExecutionReverted {
        memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
    }
    contract.Gas += returnGas

    interpreter.intPool.put(addr, inOffset, inSize, retOffset, retSize)
    return ret, nil
}

func opStaticCall(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    // Pop gas. The actual gas is in interpreter.evm.callGasTemp.
    interpreter.intPool.put(stack.pop())
    gas := interpreter.evm.callGasTemp
    // Pop other call parameters.
    addr, inOffset, inSize, retOffset, retSize := stack.pop(), stack.pop(), stack.pop(), stack.pop(), stack.pop()
    toAddr := common.BigToAddress(addr)
    // Get arguments from the memory.
    args := memory.Get(inOffset.Int64(), inSize.Int64())

    ret, returnGas, err := interpreter.evm.StaticCall(contract, toAddr, args, gas)
    if err != nil {
        stack.push(interpreter.intPool.getZero())
    } else {
        stack.push(interpreter.intPool.get().SetUint64(1))
    }
    if err == nil || err == errExecutionReverted {
        memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
    }
    contract.Gas += returnGas

    interpreter.intPool.put(addr, inOffset, inSize, retOffset, retSize)
    return ret, nil
}

func opReturn(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    offset, size := stack.pop(), stack.pop()
    ret := memory.GetPtr(offset.Int64(), size.Int64())

    interpreter.intPool.put(offset, size)
    return ret, nil
}

func opRevert(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    offset, size := stack.pop(), stack.pop()
    ret := memory.GetPtr(offset.Int64(), size.Int64())

    interpreter.intPool.put(offset, size)
    return ret, nil
}

func opStop(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    return nil, nil
}

func opSuicide(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
    balance := interpreter.evm.StateDB.GetBalance(contract.Address())
    interpreter.evm.StateDB.AddBalance(common.BigToAddress(stack.pop()), balance)

    interpreter.evm.StateDB.Suicide(contract.Address())
    return nil, nil
}

// following functions are used by the instruction jump  table

// make log instruction function
func makeLog(size int) executionFunc {
    return func(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
        topics := make([]common.Hash, size)
        mStart, mSize := stack.pop(), stack.pop()
        for i := 0; i < size; i++ {
            topics[i] = common.BigToHash(stack.pop())
        }

        d := memory.Get(mStart.Int64(), mSize.Int64())
        interpreter.evm.StateDB.AddLog(&types.Log{
            Address: contract.Address(),
            Topics:  topics,
            Data:    d,
            // This is a non-consensus field, but assigned here because
            // core/state doesn't know the current block number.
            BlockNumber: interpreter.evm.BlockNumber.Uint64(),
        })

        interpreter.intPool.put(mStart, mSize)
        return nil, nil
    }
}

// make push instruction function
func makePush(size uint64, pushByteSize int) executionFunc {
    return func(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
        codeLen := len(contract.Code)

        startMin := codeLen
        if int(*pc+1) < startMin {
            startMin = int(*pc + 1)
        }

        endMin := codeLen
        if startMin+pushByteSize < endMin {
            endMin = startMin + pushByteSize
        }

        integer := interpreter.intPool.get()
        stack.push(integer.SetBytes(common.RightPadBytes(contract.Code[startMin:endMin], pushByteSize)))

        *pc += size
        return nil, nil
    }
}

// make dup instruction function
func makeDup(size int64) executionFunc {
    return func(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
        stack.dup(interpreter.intPool, int(size))
        return nil, nil
    }
}

// make swap instruction function
func makeSwap(size int64) executionFunc {
    // switch n + 1 otherwise n would be swapped with n
    size++
    return func(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
        stack.swap(int(size))
        return nil, nil
    }
}