reworked stack

6 files changed, 352 insertions, 442 deletions

diff --git a/tests/vm/gh_test.go b/tests/vm/gh_test.go
index e3908af52..959f20463 100644
--- a/tests/vm/gh_test.go
+++ b/tests/vm/gh_test.go
@@ -11,7 +11,6 @@ import (
 	"github.com/ethereum/go-ethereum/logger"
 	"github.com/ethereum/go-ethereum/state"
 	"github.com/ethereum/go-ethereum/tests/helper"
-	"github.com/ethereum/go-ethereum/vm"
 )
 
 type Account struct {
@@ -81,11 +80,6 @@ func RunVmTest(p string, t *testing.T) {
 	helper.CreateFileTests(t, p, &tests)
 
 	for name, test := range tests {
-		vm.Debug = true
-		helper.Logger.SetLogLevel(4)
-		if name != "addmod0" {
-			continue
-		}
 		db, _ := ethdb.NewMemDatabase()
 		statedb := state.New(nil, db)
 		for addr, account := range test.Pre {
diff --git a/vm/debugger.go b/vm/debugger.go
index 9b08634c6..830a8f69d 100644
--- a/vm/debugger.go
+++ b/vm/debugger.go
@@ -1,10 +1 @@
 package vm
-
-import "github.com/ethereum/go-ethereum/state"
-
-type Debugger interface {
-	BreakHook(step int, op OpCode, mem *Memory, stack *Stack, object *state.StateObject) bool
-	StepHook(step int, op OpCode, mem *Memory, stack *Stack, object *state.StateObject) bool
-	BreakPoints() []int64
-	SetCode(byteCode []byte)
-}
diff --git a/vm/gas.go b/vm/gas.go
new file mode 100644
index 000000000..a19afeb67
--- /dev/null
+++ b/vm/gas.go
@@ -0,0 +1,86 @@
+package vm
+
+import "math/big"
+
+type req struct {
+	stack int
+	gas   *big.Int
+}
+
+var _baseCheck = map[OpCode]req{
+	//       Req stack  Gas price
+	ADD:          {2, GasFastestStep},
+	LT:           {2, GasFastestStep},
+	GT:           {2, GasFastestStep},
+	SLT:          {2, GasFastestStep},
+	SGT:          {2, GasFastestStep},
+	EQ:           {2, GasFastestStep},
+	ISZERO:       {1, GasFastestStep},
+	SUB:          {2, GasFastestStep},
+	AND:          {2, GasFastestStep},
+	OR:           {2, GasFastestStep},
+	XOR:          {2, GasFastestStep},
+	NOT:          {1, GasFastestStep},
+	BYTE:         {2, GasFastestStep},
+	CALLDATALOAD: {1, GasFastestStep},
+	CALLDATACOPY: {3, GasFastestStep},
+	MLOAD:        {1, GasFastestStep},
+	MSTORE:       {2, GasFastestStep},
+	MSTORE8:      {2, GasFastestStep},
+	CODECOPY:     {3, GasFastestStep},
+	MUL:          {2, GasFastStep},
+	DIV:          {2, GasFastStep},
+	SDIV:         {2, GasFastStep},
+	MOD:          {2, GasFastStep},
+	SMOD:         {2, GasFastStep},
+	SIGNEXTEND:   {2, GasFastStep},
+	ADDMOD:       {3, GasMidStep},
+	MULMOD:       {3, GasMidStep},
+	JUMP:         {1, GasMidStep},
+	JUMPI:        {2, GasSlowStep},
+	EXP:          {2, GasSlowStep},
+	ADDRESS:      {0, GasQuickStep},
+	ORIGIN:       {0, GasQuickStep},
+	CALLER:       {0, GasQuickStep},
+	CALLVALUE:    {0, GasQuickStep},
+	CODESIZE:     {0, GasQuickStep},
+	GASPRICE:     {0, GasQuickStep},
+	COINBASE:     {0, GasQuickStep},
+	TIMESTAMP:    {0, GasQuickStep},
+	NUMBER:       {0, GasQuickStep},
+	CALLDATASIZE: {0, GasQuickStep},
+	DIFFICULTY:   {0, GasQuickStep},
+	GASLIMIT:     {0, GasQuickStep},
+	POP:          {0, GasQuickStep},
+	PC:           {0, GasQuickStep},
+	MSIZE:        {0, GasQuickStep},
+	GAS:          {0, GasQuickStep},
+	BLOCKHASH:    {1, GasExtStep},
+	BALANCE:      {0, GasExtStep},
+	EXTCODESIZE:  {1, GasExtStep},
+	EXTCODECOPY:  {4, GasExtStep},
+	SLOAD:        {1, GasStorageGet},
+	SSTORE:       {2, Zero},
+	SHA3:         {1, GasSha3Base},
+	CREATE:       {3, GasCreate},
+	CALL:         {7, GasCall},
+	CALLCODE:     {7, GasCall},
+	JUMPDEST:     {0, GasJumpDest},
+	SUICIDE:      {1, Zero},
+	RETURN:       {2, Zero},
+}
+
+func baseCheck(op OpCode, stack *stack, gas *big.Int) {
+	if r, ok := _baseCheck[op]; ok {
+		stack.require(r.stack)
+
+		gas.Add(gas, r.gas)
+	}
+}
+
+func toWordSize(size *big.Int) *big.Int {
+	tmp := new(big.Int)
+	tmp.Add(size, u256(31))
+	tmp.Div(tmp, u256(32))
+	return tmp
+}
diff --git a/vm/memory.go b/vm/memory.go
new file mode 100644
index 000000000..2a1e6e1b9
--- /dev/null
+++ b/vm/memory.go
@@ -0,0 +1,72 @@
+package vm
+
+import "fmt"
+
+type Memory struct {
+	store []byte
+}
+
+func NewMemory() *Memory {
+	return &Memory{nil}
+}
+
+func (m *Memory) Set(offset, size uint64, value []byte) {
+	if len(value) > 0 {
+		totSize := offset + size
+		lenSize := uint64(len(m.store) - 1)
+		if totSize > lenSize {
+			// Calculate the diff between the sizes
+			diff := totSize - lenSize
+			if diff > 0 {
+				// Create a new empty slice and append it
+				newSlice := make([]byte, diff-1)
+				// Resize slice
+				m.store = append(m.store, newSlice...)
+			}
+		}
+		copy(m.store[offset:offset+size], value)
+	}
+}
+
+func (m *Memory) Resize(size uint64) {
+	if uint64(m.Len()) < size {
+		m.store = append(m.store, make([]byte, size-uint64(m.Len()))...)
+	}
+}
+
+func (self *Memory) Get(offset, size int64) (cpy []byte) {
+	if size == 0 {
+		return nil
+	}
+
+	if len(self.store) > int(offset) {
+		cpy = make([]byte, size)
+		copy(cpy, self.store[offset:offset+size])
+
+		return
+	}
+
+	return
+}
+
+func (m *Memory) Len() int {
+	return len(m.store)
+}
+
+func (m *Memory) Data() []byte {
+	return m.store
+}
+
+func (m *Memory) Print() {
+	fmt.Printf("### mem %d bytes ###\n", len(m.store))
+	if len(m.store) > 0 {
+		addr := 0
+		for i := 0; i+32 <= len(m.store); i += 32 {
+			fmt.Printf("%03d: % x\n", addr, m.store[i:i+32])
+			addr++
+		}
+	} else {
+		fmt.Println("-- empty --")
+	}
+	fmt.Println("####################")
+}
diff --git a/vm/stack.go b/vm/stack.go
index a9aafdb9d..a99cc1805 100644
--- a/vm/stack.go
+++ b/vm/stack.go
@@ -5,98 +5,53 @@ import (
 	"math/big"
 )
 
-type OpType int
-
-const (
-	tNorm = iota
-	tData
-	tExtro
-	tCrypto
-)
-
-type TxCallback func(opType OpType) bool
-
-// Simple push/pop stack mechanism
-type Stack struct {
-	data []*big.Int
-}
-
-func NewStack() *Stack {
-	return &Stack{}
-}
-
-func (st *Stack) Data() []*big.Int {
-	return st.data
-}
-
-func (st *Stack) Len() int {
-	return len(st.data)
-}
-
-func (st *Stack) Pop() *big.Int {
-	str := st.data[len(st.data)-1]
-
-	copy(st.data[:len(st.data)-1], st.data[:len(st.data)-1])
-	st.data = st.data[:len(st.data)-1]
-
-	return str
+func newStack() *stack {
+	return &stack{}
 }
 
-func (st *Stack) Popn() (*big.Int, *big.Int) {
-	ints := st.data[len(st.data)-2:]
-
-	copy(st.data[:len(st.data)-2], st.data[:len(st.data)-2])
-	st.data = st.data[:len(st.data)-2]
-
-	return ints[0], ints[1]
+type stack struct {
+	data []*big.Int
+	ptr  int
 }
 
-func (st *Stack) Peek() *big.Int {
-	str := st.data[len(st.data)-1]
-
-	return str
+func (st *stack) push(d *big.Int) {
+	if len(st.data) > st.ptr {
+		st.data[st.ptr] = d
+	} else {
+		st.data = append(st.data, d)
+	}
+	st.ptr++
 }
 
-func (st *Stack) Peekn() (*big.Int, *big.Int) {
-	ints := st.data[len(st.data)-2:]
-
-	return ints[0], ints[1]
+func (st *stack) pop() (ret *big.Int) {
+	st.ptr--
+	ret = st.data[st.ptr]
+	return
 }
 
-func (st *Stack) Swapn(n int) (*big.Int, *big.Int) {
-	st.data[len(st.data)-n], st.data[len(st.data)-1] = st.data[len(st.data)-1], st.data[len(st.data)-n]
-
-	return st.data[len(st.data)-n], st.data[len(st.data)-1]
+func (st *stack) len() int {
+	return st.ptr
 }
 
-func (st *Stack) Dupn(n int) *big.Int {
-	st.Push(st.data[len(st.data)-n])
-
-	return st.Peek()
+func (st *stack) swap(n int) {
+	st.data[st.len()-n], st.data[st.len()-1] = st.data[st.len()-1], st.data[st.len()-n]
 }
 
-func (st *Stack) Push(d *big.Int) {
-	st.data = append(st.data, new(big.Int).Set(d))
+func (st *stack) dup(n int) {
+	st.push(st.data[st.len()-n])
 }
 
-func (st *Stack) Get(amount *big.Int) []*big.Int {
-	// offset + size <= len(data)
-	length := big.NewInt(int64(len(st.data)))
-	if amount.Cmp(length) <= 0 {
-		start := new(big.Int).Sub(length, amount)
-		return st.data[start.Int64():length.Int64()]
-	}
-
-	return nil
+func (st *stack) peek() *big.Int {
+	return st.data[st.len()-1]
 }
 
-func (st *Stack) require(n int) {
-	if st.Len() < n {
-		panic(fmt.Sprintf("stack underflow (%d <=> %d)", st.Len(), n))
+func (st *stack) require(n int) {
+	if st.len() < n {
+		panic(fmt.Sprintf("stack underflow (%d <=> %d)", len(st.data), n))
 	}
 }
 
-func (st *Stack) Print() {
+func (st *stack) Print() {
 	fmt.Println("### stack ###")
 	if len(st.data) > 0 {
 		for i, val := range st.data {
@@ -107,72 +62,3 @@ func (st *Stack) Print() {
 	}
 	fmt.Println("#############")
 }
-
-type Memory struct {
-	store []byte
-}
-
-func NewMemory() *Memory {
-	return &Memory{nil}
-}
-
-func (m *Memory) Set(offset, size uint64, value []byte) {
-	if len(value) > 0 {
-		totSize := offset + size
-		lenSize := uint64(len(m.store) - 1)
-		if totSize > lenSize {
-			// Calculate the diff between the sizes
-			diff := totSize - lenSize
-			if diff > 0 {
-				// Create a new empty slice and append it
-				newSlice := make([]byte, diff-1)
-				// Resize slice
-				m.store = append(m.store, newSlice...)
-			}
-		}
-		copy(m.store[offset:offset+size], value)
-	}
-}
-
-func (m *Memory) Resize(size uint64) {
-	if uint64(m.Len()) < size {
-		m.store = append(m.store, make([]byte, size-uint64(m.Len()))...)
-	}
-}
-
-func (self *Memory) Get(offset, size int64) (cpy []byte) {
-	if size == 0 {
-		return nil
-	}
-
-	if len(self.store) > int(offset) {
-		cpy = make([]byte, size)
-		copy(cpy, self.store[offset:offset+size])
-
-		return
-	}
-
-	return
-}
-
-func (m *Memory) Len() int {
-	return len(m.store)
-}
-
-func (m *Memory) Data() []byte {
-	return m.store
-}
-
-func (m *Memory) Print() {
-	fmt.Printf("### mem %d bytes ###\n", len(m.store))
-	if len(m.store) > 0 {
-		addr := 0
-		for i := 0; i+32 <= len(m.store); i += 32 {
-			fmt.Printf("%03d: % x\n", addr, m.store[i:i+32])
-			addr++
-		}
-	} else {
-		fmt.Println("-- empty --")
-	}
-	fmt.Println("####################")
-}
diff --git a/vm/vm.go b/vm/vm.go
index 3647d7a5e..6f3945472 100644
--- a/vm/vm.go
+++ b/vm/vm.go
@@ -19,8 +19,6 @@ type Vm struct {
 	// For logging
 	debug bool
 
-	Dbg Debugger
-
 	BreakPoints []int64
 	Stepping    bool
 	Fn          string
@@ -66,10 +64,9 @@ func (self *Vm) Run(me, caller ContextRef, code []byte, value, gas, price *big.I
 
 		destinations        = analyseJumpDests(context.Code)
 		mem                 = NewMemory()
-		stack               = NewStack()
+		stack               = newStack()
 		pc           uint64 = 0
 		step                = 0
-		prevStep            = 0
 		statedb             = self.env.State()
 
 		jump = func(from uint64, to *big.Int) {
@@ -93,7 +90,6 @@ func (self *Vm) Run(me, caller ContextRef, code []byte, value, gas, price *big.I
 	}
 
 	for {
-		prevStep = step
 		// The base for all big integer arithmetic
 		base := new(big.Int)
 
@@ -101,11 +97,7 @@ func (self *Vm) Run(me, caller ContextRef, code []byte, value, gas, price *big.I
 		// 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())
-		if self.Dbg != nil {
-			//self.Dbg.Step(self, op, mem, stack, context)
-		}
-
+		self.Printf("(pc) %-3d -o- %-14s (m) %-4d (s) %-4d ", pc, op.String(), mem.Len(), stack.len())
 		newMemSize, gas := self.calculateGasAndSize(context, caller, op, statedb, mem, stack)
 
 		self.Printf("(g) %-3v (%v)", gas, context.Gas)
@@ -125,40 +117,40 @@ func (self *Vm) Run(me, caller ContextRef, code []byte, value, gas, price *big.I
 		switch op {
 		// 0x20 range
 		case ADD:
-			x, y := stack.Popn()
+			x, y := stack.pop(), stack.pop()
 			self.Printf(" %v + %v", y, x)
 
-			base.Add(y, x)
+			base.Add(x, y)
 
 			U256(base)
 
 			self.Printf(" = %v", base)
-			// Pop result back on the stack
-			stack.Push(base)
+			// pop result back on the stack
+			stack.push(base)
 		case SUB:
-			x, y := stack.Popn()
+			x, y := stack.pop(), stack.pop()
 			self.Printf(" %v - %v", y, x)
 
-			base.Sub(y, x)
+			base.Sub(x, y)
 
 			U256(base)
 
 			self.Printf(" = %v", base)
-			// Pop result back on the stack
-			stack.Push(base)
+			// pop result back on the stack
+			stack.push(base)
 		case MUL:
-			x, y := stack.Popn()
+			x, y := stack.pop(), stack.pop()
 			self.Printf(" %v * %v", y, x)
 
-			base.Mul(y, x)
+			base.Mul(x, y)
 
 			U256(base)
 
 			self.Printf(" = %v", base)
-			// Pop result back on the stack
-			stack.Push(base)
+			// pop result back on the stack
+			stack.push(base)
 		case DIV:
-			x, y := stack.Pop(), stack.Pop()
+			x, y := stack.pop(), stack.pop()
 			self.Printf(" %v / %v", x, y)
 
 			if y.Cmp(ethutil.Big0) != 0 {
@@ -168,10 +160,10 @@ func (self *Vm) Run(me, caller ContextRef, code []byte, value, gas, price *big.I
 			U256(base)
 
 			self.Printf(" = %v", base)
-			// Pop result back on the stack
-			stack.Push(base)
+			// pop result back on the stack
+			stack.push(base)
 		case SDIV:
-			x, y := S256(stack.Pop()), S256(stack.Pop())
+			x, y := S256(stack.pop()), S256(stack.pop())
 
 			self.Printf(" %v / %v", x, y)
 
@@ -191,9 +183,9 @@ func (self *Vm) Run(me, caller ContextRef, code []byte, value, gas, price *big.I
 			}
 
 			self.Printf(" = %v", base)
-			stack.Push(base)
+			stack.push(base)
 		case MOD:
-			x, y := stack.Pop(), stack.Pop()
+			x, y := stack.pop(), stack.pop()
 
 			self.Printf(" %v %% %v", x, y)
 
@@ -206,9 +198,9 @@ func (self *Vm) Run(me, caller ContextRef, code []byte, value, gas, price *big.I
 			U256(base)
 
 			self.Printf(" = %v", base)
-			stack.Push(base)
+			stack.push(base)
 		case SMOD:
-			x, y := S256(stack.Pop()), S256(stack.Pop())
+			x, y := S256(stack.pop()), S256(stack.pop())
 
 			self.Printf(" %v %% %v", x, y)
 
@@ -228,25 +220,25 @@ func (self *Vm) Run(me, caller ContextRef, code []byte, value, gas, price *big.I
 			}
 
 			self.Printf(" = %v", base)
-			stack.Push(base)
+			stack.push(base)
 
 		case EXP:
-			x, y := stack.Popn()
+			x, y := stack.pop(), stack.pop()
 
-			self.Printf(" %v ** %v", y, x)
+			self.Printf(" %v ** %v", x, y)
 
-			base.Exp(y, x, Pow256)
+			base.Exp(x, y, Pow256)
 
 			U256(base)
 
 			self.Printf(" = %v", base)
 
-			stack.Push(base)
+			stack.push(base)
 		case SIGNEXTEND:
-			back := stack.Pop().Uint64()
+			back := stack.pop().Uint64()
 			if back < 31 {
 				bit := uint(back*8 + 7)
-				num := stack.Pop()
+				num := stack.pop()
 				mask := new(big.Int).Lsh(ethutil.Big1, bit)
 				mask.Sub(mask, ethutil.Big1)
 				if ethutil.BitTest(num, int(bit)) {
@@ -259,91 +251,91 @@ func (self *Vm) Run(me, caller ContextRef, code []byte, value, gas, price *big.I
 
 				self.Printf(" = %v", num)
 
-				stack.Push(num)
+				stack.push(num)
 			}
 		case NOT:
-			base.Sub(Pow256, stack.Pop()).Sub(base, ethutil.Big1)
+			base.Sub(Pow256, stack.pop()).Sub(base, ethutil.Big1)
 
 			// Not needed
 			base = U256(base)
 
-			stack.Push(base)
+			stack.push(base)
 		case LT:
-			x, y := stack.Popn()
-			self.Printf(" %v < %v", y, x)
+			x, y := stack.pop(), stack.pop()
+			self.Printf(" %v < %v", x, y)
 			// x < y
-			if y.Cmp(x) < 0 {
-				stack.Push(ethutil.BigTrue)
+			if x.Cmp(y) < 0 {
+				stack.push(ethutil.BigTrue)
 			} else {
-				stack.Push(ethutil.BigFalse)
+				stack.push(ethutil.BigFalse)
 			}
 		case GT:
-			x, y := stack.Popn()
-			self.Printf(" %v > %v", y, x)
+			x, y := stack.pop(), stack.pop()
+			self.Printf(" %v > %v", x, y)
 
 			// x > y
-			if y.Cmp(x) > 0 {
-				stack.Push(ethutil.BigTrue)
+			if x.Cmp(y) > 0 {
+				stack.push(ethutil.BigTrue)
 			} else {
-				stack.Push(ethutil.BigFalse)
+				stack.push(ethutil.BigFalse)
 			}
 
 		case SLT:
-			y, x := S256(stack.Pop()), S256(stack.Pop())
-			self.Printf(" %v < %v", y, x)
+			x, y := S256(stack.pop()), S256(stack.pop())
+			self.Printf(" %v < %v", x, y)
 			// x < y
-			if y.Cmp(S256(x)) < 0 {
-				stack.Push(ethutil.BigTrue)
+			if x.Cmp(S256(y)) < 0 {
+				stack.push(ethutil.BigTrue)
 			} else {
-				stack.Push(ethutil.BigFalse)
+				stack.push(ethutil.BigFalse)
 			}
 		case SGT:
-			y, x := S256(stack.Pop()), S256(stack.Pop())
-			self.Printf(" %v > %v", y, x)
+			x, y := S256(stack.pop()), S256(stack.pop())
+			self.Printf(" %v > %v", x, y)
 
 			// x > y
-			if y.Cmp(x) > 0 {
-				stack.Push(ethutil.BigTrue)
+			if x.Cmp(y) > 0 {
+				stack.push(ethutil.BigTrue)
 			} else {
-				stack.Push(ethutil.BigFalse)
+				stack.push(ethutil.BigFalse)
 			}
 
 		case EQ:
-			x, y := stack.Popn()
+			x, y := stack.pop(), stack.pop()
 			self.Printf(" %v == %v", y, x)
 
 			// x == y
 			if x.Cmp(y) == 0 {
-				stack.Push(ethutil.BigTrue)
+				stack.push(ethutil.BigTrue)
 			} else {
-				stack.Push(ethutil.BigFalse)
+				stack.push(ethutil.BigFalse)
 			}
 		case ISZERO:
-			x := stack.Pop()
+			x := stack.pop()
 			if x.Cmp(ethutil.BigFalse) > 0 {
-				stack.Push(ethutil.BigFalse)
+				stack.push(ethutil.BigFalse)
 			} else {
-				stack.Push(ethutil.BigTrue)
+				stack.push(ethutil.BigTrue)
 			}
 
 			// 0x10 range
 		case AND:
-			x, y := stack.Popn()
+			x, y := stack.pop(), stack.pop()
 			self.Printf(" %v & %v", y, x)
 
-			stack.Push(base.And(y, x))
+			stack.push(base.And(x, y))
 		case OR:
-			x, y := stack.Popn()
-			self.Printf(" %v | %v", y, x)
+			x, y := stack.pop(), stack.pop()
+			self.Printf(" %v | %v", x, y)
 
-			stack.Push(base.Or(y, x))
+			stack.push(base.Or(x, y))
 		case XOR:
-			x, y := stack.Popn()
-			self.Printf(" %v ^ %v", y, x)
+			x, y := stack.pop(), stack.pop()
+			self.Printf(" %v ^ %v", x, y)
 
-			stack.Push(base.Xor(y, x))
+			stack.push(base.Xor(x, y))
 		case BYTE:
-			val, th := stack.Popn()
+			th, val := stack.pop(), stack.pop()
 
 			if th.Cmp(big.NewInt(32)) < 0 {
 				byt := big.NewInt(int64(ethutil.LeftPadBytes(val.Bytes(), 32)[th.Int64()]))
@@ -355,12 +347,12 @@ func (self *Vm) Run(me, caller ContextRef, code []byte, value, gas, price *big.I
 
 			self.Printf(" => 0x%x", base.Bytes())
 
-			stack.Push(base)
+			stack.push(base)
 		case ADDMOD:
 
-			x := stack.Pop()
-			y := stack.Pop()
-			z := stack.Pop()
+			x := stack.pop()
+			y := stack.pop()
+			z := stack.pop()
 
 			add := new(big.Int).Add(x, y)
 			if len(z.Bytes()) > 0 { // NOT 0x0
@@ -371,12 +363,12 @@ func (self *Vm) Run(me, caller ContextRef, code []byte, value, gas, price *big.I
 
 			self.Printf(" %v + %v %% %v = %v", x, y, z, base)
 
-			stack.Push(base)
+			stack.push(base)
 		case MULMOD:
 
-			x := stack.Pop()
-			y := stack.Pop()
-			z := stack.Pop()
+			x := stack.pop()
+			y := stack.pop()
+			z := stack.pop()
 
 			mul := new(big.Int).Mul(x, y)
 			if len(z.Bytes()) > 0 { // NOT 0x0
@@ -387,24 +379,24 @@ func (self *Vm) Run(me, caller ContextRef, code []byte, value, gas, price *big.I
 
 			self.Printf(" %v + %v %% %v = %v", x, y, z, base)
 
-			stack.Push(base)
+			stack.push(base)
 
 			// 0x20 range
 		case SHA3:
-			size, offset := stack.Popn()
+			size, offset := stack.pop(), stack.pop()
 			data := crypto.Sha3(mem.Get(offset.Int64(), size.Int64()))
 
-			stack.Push(ethutil.BigD(data))
+			stack.push(ethutil.BigD(data))
 
 			self.Printf(" => (%v) %x", size, data)
 			// 0x30 range
 		case ADDRESS:
-			stack.Push(ethutil.BigD(context.Address()))
+			stack.push(ethutil.BigD(context.Address()))
 
 			self.Printf(" => %x", context.Address())
 		case BALANCE:
 
-			addr := stack.Pop().Bytes()
+			addr := stack.pop().Bytes()
 			var balance *big.Int
 			if statedb.GetStateObject(addr) != nil {
 				balance = statedb.GetBalance(addr)
@@ -412,27 +404,27 @@ func (self *Vm) Run(me, caller ContextRef, code []byte, value, gas, price *big.I
 				balance = base
 			}
 
-			stack.Push(balance)
+			stack.push(balance)
 
 			self.Printf(" => %v (%x)", balance, addr)
 		case ORIGIN:
 			origin := self.env.Origin()
 
-			stack.Push(ethutil.BigD(origin))
+			stack.push(ethutil.BigD(origin))
 
 			self.Printf(" => %x", origin)
 		case CALLER:
 			caller := context.caller.Address()
-			stack.Push(ethutil.BigD(caller))
+			stack.push(ethutil.BigD(caller))
 
 			self.Printf(" => %x", caller)
 		case CALLVALUE:
-			stack.Push(value)
+			stack.push(value)
 
 			self.Printf(" => %v", value)
 		case CALLDATALOAD:
 			var (
-				offset  = stack.Pop()
+				offset  = stack.pop()
 				data    = make([]byte, 32)
 				lenData = big.NewInt(int64(len(callData)))
 			)
@@ -446,18 +438,18 @@ func (self *Vm) Run(me, caller ContextRef, code []byte, value, gas, price *big.I
 
 			self.Printf(" => 0x%x", data)
 
-			stack.Push(ethutil.BigD(data))
+			stack.push(ethutil.BigD(data))
 		case CALLDATASIZE:
 			l := int64(len(callData))
-			stack.Push(big.NewInt(l))
+			stack.push(big.NewInt(l))
 
 			self.Printf(" => %d", l)
 		case CALLDATACOPY:
 			var (
 				size = uint64(len(callData))
-				mOff = stack.Pop().Uint64()
-				cOff = stack.Pop().Uint64()
-				l    = stack.Pop().Uint64()
+				mOff = stack.pop().Uint64()
+				cOff = stack.pop().Uint64()
+				l    = stack.pop().Uint64()
 			)
 
 			if cOff > size {
@@ -475,7 +467,7 @@ func (self *Vm) Run(me, caller ContextRef, code []byte, value, gas, price *big.I
 		case CODESIZE, EXTCODESIZE:
 			var code []byte
 			if op == EXTCODESIZE {
-				addr := stack.Pop().Bytes()
+				addr := stack.pop().Bytes()
 
 				code = statedb.GetCode(addr)
 			} else {
@@ -483,21 +475,21 @@ func (self *Vm) Run(me, caller ContextRef, code []byte, value, gas, price *big.I
 			}
 
 			l := big.NewInt(int64(len(code)))
-			stack.Push(l)
+			stack.push(l)
 
 			self.Printf(" => %d", l)
 		case CODECOPY, EXTCODECOPY:
 			var code []byte
 			if op == EXTCODECOPY {
-				code = statedb.GetCode(stack.Pop().Bytes())
+				code = statedb.GetCode(stack.pop().Bytes())
 			} else {
 				code = context.Code
 			}
 			context := NewContext(nil, nil, code, ethutil.Big0, ethutil.Big0)
 			var (
-				mOff = stack.Pop().Uint64()
-				cOff = stack.Pop().Uint64()
-				l    = stack.Pop().Uint64()
+				mOff = stack.pop().Uint64()
+				cOff = stack.pop().Uint64()
+				l    = stack.pop().Uint64()
 			)
 			codeCopy := context.GetCode(cOff, l)
 
@@ -505,80 +497,80 @@ func (self *Vm) Run(me, caller ContextRef, code []byte, value, gas, price *big.I
 
 			self.Printf(" => [%v, %v, %v] %x", mOff, cOff, l, codeCopy)
 		case GASPRICE:
-			stack.Push(context.Price)
+			stack.push(context.Price)
 
 			self.Printf(" => %x", context.Price)
 
 			// 0x40 range
 		case BLOCKHASH:
-			num := stack.Pop()
+			num := stack.pop()
 
 			n := new(big.Int).Sub(self.env.BlockNumber(), ethutil.Big257)
 			if num.Cmp(n) > 0 && num.Cmp(self.env.BlockNumber()) < 0 {
-				stack.Push(ethutil.BigD(self.env.GetHash(num.Uint64())))
+				stack.push(ethutil.BigD(self.env.GetHash(num.Uint64())))
 			} else {
-				stack.Push(ethutil.Big0)
+				stack.push(ethutil.Big0)
 			}
 
-			self.Printf(" => 0x%x", stack.Peek().Bytes())
+			self.Printf(" => 0x%x", stack.peek().Bytes())
 		case COINBASE:
 			coinbase := self.env.Coinbase()
 
-			stack.Push(ethutil.BigD(coinbase))
+			stack.push(ethutil.BigD(coinbase))
 
 			self.Printf(" => 0x%x", coinbase)
 		case TIMESTAMP:
 			time := self.env.Time()
 
-			stack.Push(big.NewInt(time))
+			stack.push(big.NewInt(time))
 
 			self.Printf(" => 0x%x", time)
 		case NUMBER:
 			number := self.env.BlockNumber()
 
-			stack.Push(U256(number))
+			stack.push(U256(number))
 
 			self.Printf(" => 0x%x", number.Bytes())
 		case DIFFICULTY:
 			difficulty := self.env.Difficulty()
 
-			stack.Push(difficulty)
+			stack.push(difficulty)
 
 			self.Printf(" => 0x%x", difficulty.Bytes())
 		case GASLIMIT:
 			self.Printf(" => %v", self.env.GasLimit())
 
-			stack.Push(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 := uint64(op - PUSH1 + 1)
 			byts := context.GetRangeValue(pc+1, a)
-			// Push value to stack
-			stack.Push(ethutil.BigD(byts))
+			// push value to stack
+			stack.push(ethutil.BigD(byts))
 			pc += a
 
 			step += int(op) - int(PUSH1) + 1
 
 			self.Printf(" => 0x%x", byts)
 		case POP:
-			stack.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.Dupn(n)
+			stack.dup(n)
 
-			self.Printf(" => [%d] 0x%x", n, stack.Peek().Bytes())
+			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)
-			x, y := stack.Swapn(n)
+			stack.swap(n)
 
-			self.Printf(" => [%d] %x [0] %x", n, x.Bytes(), y.Bytes())
+			self.Printf(" => [%d]", n)
 		case LOG0, LOG1, LOG2, LOG3, LOG4:
 			n := int(op - LOG0)
 			topics := make([][]byte, n)
-			mSize, mStart := stack.Popn()
+			mStart, mSize := stack.pop(), stack.pop()
 			for i := 0; i < n; i++ {
-				topics[i] = ethutil.LeftPadBytes(stack.Pop().Bytes(), 32)
+				topics[i] = ethutil.LeftPadBytes(stack.pop().Bytes(), 32)
 			}
 
 			data := mem.Get(mStart.Int64(), mSize.Int64())
@@ -587,41 +579,40 @@ func (self *Vm) Run(me, caller ContextRef, code []byte, value, gas, price *big.I
 
 			self.Printf(" => %v", log)
 		case MLOAD:
-			offset := stack.Pop()
+			offset := stack.pop()
 			val := ethutil.BigD(mem.Get(offset.Int64(), 32))
-			stack.Push(val)
+			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
-			val, mStart := stack.Popn()
+			// pop value of the stack
+			mStart, val := stack.pop(), stack.pop()
 			mem.Set(mStart.Uint64(), 32, ethutil.BigToBytes(val, 256))
 
 			self.Printf(" => 0x%x", val)
 		case MSTORE8:
-			off := stack.Pop()
-			val := stack.Pop()
+			off, val := stack.pop(), stack.pop()
 
 			mem.store[off.Int64()] = byte(val.Int64() & 0xff)
 
 			self.Printf(" => [%v] 0x%x", off, val)
 		case SLOAD:
-			loc := stack.Pop()
+			loc := stack.pop()
 			val := ethutil.BigD(statedb.GetState(context.Address(), loc.Bytes()))
-			stack.Push(val)
+			stack.push(val)
 
 			self.Printf(" {0x%x : 0x%x}", loc.Bytes(), val.Bytes())
 		case SSTORE:
-			val, loc := stack.Popn()
+			loc, val := stack.pop(), stack.pop()
 			statedb.SetState(context.Address(), loc.Bytes(), val)
 
 			self.Printf(" {0x%x : 0x%x}", loc.Bytes(), val.Bytes())
 		case JUMP:
-			jump(pc, stack.Pop())
+			jump(pc, stack.pop())
 
 			continue
 		case JUMPI:
-			cond, pos := stack.Popn()
+			pos, cond := stack.pop(), stack.pop()
 
 			if cond.Cmp(ethutil.BigTrue) >= 0 {
 				jump(pc, pos)
@@ -633,19 +624,19 @@ func (self *Vm) Run(me, caller ContextRef, code []byte, value, gas, price *big.I
 
 		case JUMPDEST:
 		case PC:
-			stack.Push(big.NewInt(int64(pc)))
+			stack.push(big.NewInt(int64(pc)))
 		case MSIZE:
-			stack.Push(big.NewInt(int64(mem.Len())))
+			stack.push(big.NewInt(int64(mem.Len())))
 		case GAS:
-			stack.Push(context.Gas)
+			stack.push(context.Gas)
 
 			self.Printf(" => %x", context.Gas)
 			// 0x60 range
 		case CREATE:
 
 			var (
-				value        = stack.Pop()
-				size, offset = stack.Popn()
+				value        = stack.pop()
+				offset, size = stack.pop(), stack.pop()
 				input        = mem.Get(offset.Int64(), size.Int64())
 				gas          = new(big.Int).Set(context.Gas)
 				addr         []byte
@@ -655,7 +646,7 @@ func (self *Vm) Run(me, caller ContextRef, code []byte, value, gas, price *big.I
 			context.UseGas(context.Gas)
 			ret, suberr, ref := self.env.Create(context, nil, input, gas, price, value)
 			if suberr != nil {
-				stack.Push(ethutil.BigFalse)
+				stack.push(ethutil.BigFalse)
 
 				self.Printf(" (*) 0x0 %v", suberr)
 			} else {
@@ -668,23 +659,19 @@ func (self *Vm) Run(me, caller ContextRef, code []byte, value, gas, price *big.I
 				}
 				addr = ref.Address()
 
-				stack.Push(ethutil.BigD(addr))
+				stack.push(ethutil.BigD(addr))
 
 			}
 
-			// Debug hook
-			if self.Dbg != nil {
-				self.Dbg.SetCode(context.Code)
-			}
 		case CALL, CALLCODE:
-			gas := stack.Pop()
-			// Pop gas and value of the stack.
-			value, addr := stack.Popn()
+			gas := stack.pop()
+			// pop gas and value of the stack.
+			addr, value := stack.pop(), stack.pop()
 			value = U256(value)
-			// Pop input size and offset
-			inSize, inOffset := stack.Popn()
-			// Pop return size and offset
-			retSize, retOffset := stack.Popn()
+			// pop input size and offset
+			inOffset, inSize := stack.pop(), stack.pop()
+			// pop return size and offset
+			retOffset, retSize := stack.pop(), stack.pop()
 
 			address := ethutil.Address(addr.Bytes())
 			self.Printf(" => %x", address).Endl()
@@ -707,30 +694,24 @@ func (self *Vm) Run(me, caller ContextRef, code []byte, value, gas, price *big.I
 			}
 
 			if err != nil {
-				stack.Push(ethutil.BigFalse)
+				stack.push(ethutil.BigFalse)
 
 				vmlogger.Debugln(err)
 			} else {
-				stack.Push(ethutil.BigTrue)
+				stack.push(ethutil.BigTrue)
 
 				mem.Set(retOffset.Uint64(), retSize.Uint64(), ret)
 			}
 			self.Printf("resume %x (%v)", context.Address(), context.Gas)
-
-			// Debug hook
-			if self.Dbg != nil {
-				self.Dbg.SetCode(context.Code)
-			}
-
 		case RETURN:
-			size, offset := stack.Popn()
+			offset, size := stack.pop(), stack.pop()
 			ret := mem.Get(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(stack.Pop().Bytes())
+			receiver := statedb.GetOrNewStateObject(stack.pop().Bytes())
 			balance := statedb.GetBalance(context.Address())
 
 			self.Printf(" => (%x) %v", receiver.Address()[:4], balance)
@@ -753,117 +734,17 @@ func (self *Vm) Run(me, caller ContextRef, code []byte, value, gas, price *big.I
 		pc++
 
 		self.Endl()
-
-		if self.Dbg != nil {
-			for _, instrNo := range self.Dbg.BreakPoints() {
-				if pc == uint64(instrNo) {
-					self.Stepping = true
-
-					if !self.Dbg.BreakHook(prevStep, op, mem, stack, statedb.GetStateObject(context.Address())) {
-						return nil, nil
-					}
-				} else if self.Stepping {
-					if !self.Dbg.StepHook(prevStep, op, mem, stack, statedb.GetStateObject(context.Address())) {
-						return nil, nil
-					}
-				}
-			}
-		}
-
 	}
 }
 
-type req struct {
-	stack int
-	gas   *big.Int
-}
-
-var _baseCheck = map[OpCode]req{
-	//       Req Stack  Gas price
-	ADD:          {2, GasFastestStep},
-	LT:           {2, GasFastestStep},
-	GT:           {2, GasFastestStep},
-	SLT:          {2, GasFastestStep},
-	SGT:          {2, GasFastestStep},
-	EQ:           {2, GasFastestStep},
-	ISZERO:       {1, GasFastestStep},
-	SUB:          {2, GasFastestStep},
-	AND:          {2, GasFastestStep},
-	OR:           {2, GasFastestStep},
-	XOR:          {2, GasFastestStep},
-	NOT:          {1, GasFastestStep},
-	BYTE:         {2, GasFastestStep},
-	CALLDATALOAD: {1, GasFastestStep},
-	CALLDATACOPY: {3, GasFastestStep},
-	MLOAD:        {1, GasFastestStep},
-	MSTORE:       {2, GasFastestStep},
-	MSTORE8:      {2, GasFastestStep},
-	CODECOPY:     {3, GasFastestStep},
-	MUL:          {2, GasFastStep},
-	DIV:          {2, GasFastStep},
-	SDIV:         {2, GasFastStep},
-	MOD:          {2, GasFastStep},
-	SMOD:         {2, GasFastStep},
-	SIGNEXTEND:   {2, GasFastStep},
-	ADDMOD:       {3, GasMidStep},
-	MULMOD:       {3, GasMidStep},
-	JUMP:         {1, GasMidStep},
-	JUMPI:        {2, GasSlowStep},
-	EXP:          {2, GasSlowStep},
-	ADDRESS:      {0, GasQuickStep},
-	ORIGIN:       {0, GasQuickStep},
-	CALLER:       {0, GasQuickStep},
-	CALLVALUE:    {0, GasQuickStep},
-	CODESIZE:     {0, GasQuickStep},
-	GASPRICE:     {0, GasQuickStep},
-	COINBASE:     {0, GasQuickStep},
-	TIMESTAMP:    {0, GasQuickStep},
-	NUMBER:       {0, GasQuickStep},
-	CALLDATASIZE: {0, GasQuickStep},
-	DIFFICULTY:   {0, GasQuickStep},
-	GASLIMIT:     {0, GasQuickStep},
-	POP:          {0, GasQuickStep},
-	PC:           {0, GasQuickStep},
-	MSIZE:        {0, GasQuickStep},
-	GAS:          {0, GasQuickStep},
-	BLOCKHASH:    {1, GasExtStep},
-	BALANCE:      {0, GasExtStep},
-	EXTCODESIZE:  {1, GasExtStep},
-	EXTCODECOPY:  {4, GasExtStep},
-	SLOAD:        {1, GasStorageGet},
-	SSTORE:       {2, Zero},
-	SHA3:         {1, GasSha3Base},
-	CREATE:       {3, GasCreate},
-	CALL:         {7, GasCall},
-	CALLCODE:     {7, GasCall},
-	JUMPDEST:     {0, GasJumpDest},
-	SUICIDE:      {1, Zero},
-	RETURN:       {2, Zero},
-}
-
-func baseCheck(op OpCode, stack *Stack, gas *big.Int) {
-	if r, ok := _baseCheck[op]; ok {
-		stack.require(r.stack)
-
-		gas.Add(gas, r.gas)
-	}
-}
-
-func toWordSize(size *big.Int) *big.Int {
-	tmp := new(big.Int)
-	tmp.Add(size, u256(31))
-	tmp.Div(tmp, u256(32))
-	return tmp
-}
-
-func (self *Vm) calculateGasAndSize(context *Context, caller ContextRef, op OpCode, statedb *state.StateDB, mem *Memory, stack *Stack) (*big.Int, *big.Int) {
+func (self *Vm) calculateGasAndSize(context *Context, caller ContextRef, op OpCode, statedb *state.StateDB, mem *Memory, stack *stack) (*big.Int, *big.Int) {
 	var (
 		gas                 = new(big.Int)
 		newMemSize *big.Int = new(big.Int)
 	)
 	baseCheck(op, stack, gas)
 
-	// Stack Check, memory resize & gas phase
+	// stack Check, memory resize & gas phase
 	switch op {
 	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:
 		gas.Set(GasFastestStep)
@@ -879,7 +760,7 @@ func (self *Vm) calculateGasAndSize(context *Context, caller ContextRef, op OpCo
 		n := int(op - LOG0)
 		stack.require(n + 2)
 
-		mSize, mStart := stack.Peekn()
+		mSize, mStart := stack.data[stack.len()-2], stack.data[stack.len()-1]
 
 		gas.Add(gas, GasLogBase)
 		gas.Add(gas, new(big.Int).Mul(big.NewInt(int64(n)), GasLogTopic))
@@ -887,12 +768,12 @@ func (self *Vm) calculateGasAndSize(context *Context, caller ContextRef, op OpCo
 
 		newMemSize = calcMemSize(mStart, mSize)
 	case EXP:
-		gas.Add(gas, new(big.Int).Mul(big.NewInt(int64(len(stack.data[stack.Len()-2].Bytes()))), GasExpByte))
+		gas.Add(gas, new(big.Int).Mul(big.NewInt(int64(len(stack.data[stack.len()-2].Bytes()))), GasExpByte))
 	case SSTORE:
 		stack.require(2)
 
 		var g *big.Int
-		y, x := stack.Peekn()
+		y, x := stack.data[stack.len()-2], stack.data[stack.len()-1]
 		val := statedb.GetState(context.Address(), x.Bytes())
 		if len(val) == 0 && len(y.Bytes()) > 0 {
 			// 0 => non 0
@@ -911,51 +792,51 @@ func (self *Vm) calculateGasAndSize(context *Context, caller ContextRef, op OpCo
 			statedb.Refund(self.env.Origin(), RefundSuicide)
 		}
 	case MLOAD:
-		newMemSize = calcMemSize(stack.Peek(), u256(32))
+		newMemSize = calcMemSize(stack.peek(), u256(32))
 	case MSTORE8:
-		newMemSize = calcMemSize(stack.Peek(), u256(1))
+		newMemSize = calcMemSize(stack.peek(), u256(1))
 	case MSTORE:
-		newMemSize = calcMemSize(stack.Peek(), u256(32))
+		newMemSize = calcMemSize(stack.peek(), u256(32))
 	case RETURN:
-		newMemSize = calcMemSize(stack.Peek(), stack.data[stack.Len()-2])
+		newMemSize = calcMemSize(stack.peek(), stack.data[stack.len()-2])
 	case SHA3:
-		newMemSize = calcMemSize(stack.Peek(), stack.data[stack.Len()-2])
+		newMemSize = calcMemSize(stack.peek(), stack.data[stack.len()-2])
 
-		words := toWordSize(stack.data[stack.Len()-2])
+		words := toWordSize(stack.data[stack.len()-2])
 		gas.Add(gas, words.Mul(words, GasSha3Word))
 	case CALLDATACOPY:
-		newMemSize = calcMemSize(stack.Peek(), stack.data[stack.Len()-3])
+		newMemSize = calcMemSize(stack.peek(), stack.data[stack.len()-3])
 
-		words := toWordSize(stack.data[stack.Len()-3])
+		words := toWordSize(stack.data[stack.len()-3])
 		gas.Add(gas, words.Mul(words, GasCopyWord))
 	case CODECOPY:
-		newMemSize = calcMemSize(stack.Peek(), stack.data[stack.Len()-3])
+		newMemSize = calcMemSize(stack.peek(), stack.data[stack.len()-3])
 
-		words := toWordSize(stack.data[stack.Len()-3])
+		words := toWordSize(stack.data[stack.len()-3])
 		gas.Add(gas, words.Mul(words, GasCopyWord))
 	case EXTCODECOPY:
-		newMemSize = calcMemSize(stack.data[stack.Len()-2], stack.data[stack.Len()-4])
+		newMemSize = calcMemSize(stack.data[stack.len()-2], stack.data[stack.len()-4])
 
-		words := toWordSize(stack.data[stack.Len()-4])
+		words := toWordSize(stack.data[stack.len()-4])
 		gas.Add(gas, words.Mul(words, GasCopyWord))
 
 	case CREATE:
-		newMemSize = calcMemSize(stack.data[stack.Len()-2], stack.data[stack.Len()-3])
+		newMemSize = calcMemSize(stack.data[stack.len()-2], stack.data[stack.len()-3])
 	case CALL, CALLCODE:
-		gas.Add(gas, stack.data[stack.Len()-1])
+		gas.Add(gas, stack.data[stack.len()-1])
 
 		if op == CALL {
-			if self.env.State().GetStateObject(stack.data[stack.Len()-2].Bytes()) == nil {
+			if self.env.State().GetStateObject(stack.data[stack.len()-2].Bytes()) == nil {
 				gas.Add(gas, GasCallNewAccount)
 			}
 		}
 
-		if len(stack.data[stack.Len()-3].Bytes()) > 0 {
+		if len(stack.data[stack.len()-3].Bytes()) > 0 {
 			gas.Add(gas, GasCallValueTransfer)
 		}
 
-		x := calcMemSize(stack.data[stack.Len()-6], stack.data[stack.Len()-7])
-		y := calcMemSize(stack.data[stack.Len()-4], stack.data[stack.Len()-5])
+		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 = ethutil.BigMax(x, y)
 	}