Refactored VM to two separate VMs; std & debug

Standard VM should be about 10x faster than the debug VM. Some error
checking has been removed, all of the log statements and therefor quite
some unnecessary if-statements.

10 files changed, 1147 insertions, 344 deletions

diff --git a/ethvm/closure.go b/ethvm/closure.go
index c047a83b7..0cd3c768c 100644
--- a/ethvm/closure.go
+++ b/ethvm/closure.go
@@ -58,6 +58,26 @@ func (c *Closure) Get(x *big.Int) *ethutil.Value {
 	return c.Gets(x, big.NewInt(1))
 }
 
+func (c *Closure) GetOp(x int) OpCode {
+	return OpCode(c.GetByte(x))
+}
+
+func (c *Closure) GetByte(x int) byte {
+	if x < len(c.Code) {
+		return c.Code[x]
+	}
+
+	return 0
+}
+
+func (c *Closure) GetBytes(x, y int) []byte {
+	if x >= len(c.Code) || y >= len(c.Code) {
+		return nil
+	}
+
+	return c.Code[x : x+y]
+}
+
 func (c *Closure) Gets(x, y *big.Int) *ethutil.Value {
 	if x.Int64() >= int64(len(c.Code)) || y.Int64() >= int64(len(c.Code)) {
 		return ethutil.NewValue(0)
@@ -76,7 +96,7 @@ func (c *Closure) Address() []byte {
 	return c.object.Address()
 }
 
-func (c *Closure) Call(vm *Vm, args []byte) ([]byte, *big.Int, error) {
+func (c *Closure) Call(vm VirtualMachine, args []byte) ([]byte, *big.Int, error) {
 	c.Args = args
 
 	ret, err := vm.RunClosure(c)
diff --git a/ethvm/common.go b/ethvm/common.go
index 5a3aec648..6854a5219 100644
--- a/ethvm/common.go
+++ b/ethvm/common.go
@@ -1,13 +1,23 @@
 package ethvm
 
 import (
+	"math/big"
+
 	"github.com/ethereum/eth-go/ethlog"
 	"github.com/ethereum/eth-go/ethutil"
-	"math/big"
 )
 
 var vmlogger = ethlog.NewLogger("VM")
 
+type Type int
+
+const (
+	StandardVmTy Type = iota
+	DebugVmTy
+
+	MaxVmTy
+)
+
 var (
 	GasStep    = big.NewInt(1)
 	GasSha     = big.NewInt(20)
@@ -24,4 +34,32 @@ var (
 
 	LogTyPretty byte = 0x1
 	LogTyDiff   byte = 0x2
+
+	To256 = ethutil.To256
 )
+
+const MaxCallDepth = 1024
+
+func calcMemSize(off, l *big.Int) *big.Int {
+	if l.Cmp(ethutil.Big0) == 0 {
+		return ethutil.Big0
+	}
+
+	return new(big.Int).Add(off, l)
+}
+
+// Simple helper
+func u256(n int64) *big.Int {
+	return big.NewInt(n)
+}
+
+// Mainly used for print variables and passing to Print*
+func toValue(val *big.Int) interface{} {
+	// Let's assume a string on right padded zero's
+	b := val.Bytes()
+	if b[0] != 0 && b[len(b)-1] == 0x0 && b[len(b)-2] == 0x0 {
+		return string(b)
+	}
+
+	return val
+}
diff --git a/ethvm/debugger.go b/ethvm/debugger.go
new file mode 100644
index 000000000..6144b5d6a
--- /dev/null
+++ b/ethvm/debugger.go
@@ -0,0 +1,10 @@
+package ethvm
+
+import "github.com/ethereum/eth-go/ethstate"
+
+type Debugger interface {
+	BreakHook(step int, op OpCode, mem *Memory, stack *Stack, object *ethstate.StateObject) bool
+	StepHook(step int, op OpCode, mem *Memory, stack *Stack, object *ethstate.StateObject) bool
+	BreakPoints() []int64
+	SetCode(byteCode []byte)
+}
diff --git a/ethvm/environment.go b/ethvm/environment.go
new file mode 100644
index 000000000..e261f8462
--- /dev/null
+++ b/ethvm/environment.go
@@ -0,0 +1,26 @@
+package ethvm
+
+import (
+	"math/big"
+
+	"github.com/ethereum/eth-go/ethstate"
+	"github.com/ethereum/eth-go/ethutil"
+)
+
+type Environment interface {
+	State() *ethstate.State
+
+	Origin() []byte
+	BlockNumber() *big.Int
+	PrevHash() []byte
+	Coinbase() []byte
+	Time() int64
+	Difficulty() *big.Int
+	Value() *big.Int
+	BlockHash() []byte
+}
+
+type Object interface {
+	GetStorage(key *big.Int) *ethutil.Value
+	SetStorage(key *big.Int, value *ethutil.Value)
+}
diff --git a/ethvm/execution.go b/ethvm/execution.go
new file mode 100644
index 000000000..84bc50778
--- /dev/null
+++ b/ethvm/execution.go
@@ -0,0 +1,79 @@
+package ethvm
+
+import (
+	"fmt"
+	"math/big"
+
+	"github.com/ethereum/eth-go/ethstate"
+	"github.com/ethereum/eth-go/ethutil"
+)
+
+type Execution struct {
+	vm                VirtualMachine
+	closure           *Closure
+	address, input    []byte
+	gas, price, value *big.Int
+	object            *ethstate.StateObject
+}
+
+func NewExecution(vm VirtualMachine, address, input []byte, gas, gasPrice, value *big.Int) *Execution {
+	return &Execution{vm: vm, address: address, input: input, gas: gas, price: gasPrice, value: value}
+}
+
+func (self *Execution) Addr() []byte {
+	return self.address
+}
+
+func (self *Execution) Exec(codeAddr []byte, caller ClosureRef) (ret []byte, err error) {
+	env := self.vm.Env()
+
+	snapshot := env.State().Copy()
+
+	msg := env.State().Manifest().AddMessage(&ethstate.Message{
+		To: self.address, From: caller.Address(),
+		Input:  self.input,
+		Origin: env.Origin(),
+		Block:  env.BlockHash(), Timestamp: env.Time(), Coinbase: env.Coinbase(), Number: env.BlockNumber(),
+		Value: self.value,
+	})
+
+	object := caller.Object()
+	if object.Balance.Cmp(self.value) < 0 {
+		caller.ReturnGas(self.gas, self.price)
+
+		err = fmt.Errorf("Insufficient funds to transfer value. Req %v, has %v", self.value, object.Balance)
+	} else {
+		stateObject := env.State().GetOrNewStateObject(self.address)
+		self.object = stateObject
+
+		caller.Object().SubAmount(self.value)
+		stateObject.AddAmount(self.value)
+
+		// Precompiled contracts (address.go) 1, 2 & 3.
+		if p := Precompiled[ethutil.BigD(codeAddr).Uint64()]; p != nil {
+			if self.gas.Cmp(p.Gas) >= 0 {
+				ret = p.Call(self.input)
+			}
+		} else {
+			if self.vm.Depth() == MaxCallDepth {
+				return nil, fmt.Errorf("Max call depth exceeded (%d)", MaxCallDepth)
+			}
+
+			// Retrieve the executing code
+			code := env.State().GetCode(codeAddr)
+
+			// Create a new callable closure
+			c := NewClosure(msg, caller, stateObject, code, self.gas, self.price)
+			// Executer the closure and get the return value (if any)
+			ret, _, err = c.Call(self.vm, self.input)
+
+			msg.Output = ret
+		}
+	}
+
+	if err != nil {
+		env.State().Set(snapshot)
+	}
+
+	return
+}
diff --git a/ethvm/types.go b/ethvm/types.go
index 68d1c9409..36fa1d526 100644
--- a/ethvm/types.go
+++ b/ethvm/types.go
@@ -4,7 +4,7 @@ import (
 	"fmt"
 )
 
-type OpCode int
+type OpCode byte
 
 // Op codes
 const (
diff --git a/ethvm/virtual_machine.go b/ethvm/virtual_machine.go
new file mode 100644
index 000000000..6dd837049
--- /dev/null
+++ b/ethvm/virtual_machine.go
@@ -0,0 +1,7 @@
+package ethvm
+
+type VirtualMachine interface {
+	Env() Environment
+	RunClosure(*Closure) ([]byte, error)
+	Depth() int
+}
diff --git a/ethvm/vm.go b/ethvm/vm.go
index 0c9fa6f14..0fb97e652 100644
--- a/ethvm/vm.go
+++ b/ethvm/vm.go
@@ -5,118 +5,48 @@ import (
 	"math/big"
 
 	"github.com/ethereum/eth-go/ethcrypto"
-	"github.com/ethereum/eth-go/ethstate"
 	"github.com/ethereum/eth-go/ethutil"
 )
 
-// Shortcut :-)
-var To256 = ethutil.To256
-
-const MaxCallDepth = 1024
-
-type Debugger interface {
-	BreakHook(step int, op OpCode, mem *Memory, stack *Stack, object *ethstate.StateObject) bool
-	StepHook(step int, op OpCode, mem *Memory, stack *Stack, object *ethstate.StateObject) bool
-	BreakPoints() []int64
-	SetCode(byteCode []byte)
-}
-
 type Vm struct {
-	env Environment
-
-	Verbose bool
-
-	logTy  byte
-	logStr string
-
-	err error
-
-	// Debugging
-	Dbg Debugger
-
-	BreakPoints []int64
-	Stepping    bool
-	Fn          string
-
-	Recoverable bool
-
+	env   Environment
+	err   error
 	depth int
 }
 
-type Environment interface {
-	State() *ethstate.State
-
-	Origin() []byte
-	BlockNumber() *big.Int
-	PrevHash() []byte
-	Coinbase() []byte
-	Time() int64
-	Difficulty() *big.Int
-	Value() *big.Int
-	BlockHash() []byte
-}
-
-type Object interface {
-	GetStorage(key *big.Int) *ethutil.Value
-	SetStorage(key *big.Int, value *ethutil.Value)
-}
-
-func New(env Environment) *Vm {
-	lt := LogTyPretty
-	if ethutil.Config.Diff {
-		lt = LogTyDiff
+func New(env Environment, typ Type) VirtualMachine {
+	switch typ {
+	case DebugVmTy:
+		return NewDebugVm(env)
+	default:
+		return &Vm{env: env}
 	}
-
-	return &Vm{env: env, logTy: lt, Recoverable: true}
-}
-
-func calcMemSize(off, l *big.Int) *big.Int {
-	if l.Cmp(ethutil.Big0) == 0 {
-		return ethutil.Big0
-	}
-
-	return new(big.Int).Add(off, l)
-}
-
-// Simple helper
-func u256(n int64) *big.Int {
-	return big.NewInt(n)
 }
 
 func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 	self.depth++
 
-	if self.Recoverable {
-		// Recover from any require exception
-		defer func() {
-			if r := recover(); r != nil {
-				ret = closure.Return(nil)
-				err = fmt.Errorf("%v", r)
-			}
-		}()
-	}
-
-	// Debug hook
-	if self.Dbg != nil {
-		self.Dbg.SetCode(closure.Code)
-	}
+	// Recover from any require exception
+	defer func() {
+		if r := recover(); r != nil {
+			ret = closure.Return(nil)
+			err = fmt.Errorf("%v", r)
+		}
+	}()
 
 	// Don't bother with the execution if there's no code.
 	if len(closure.Code) == 0 {
 		return closure.Return(nil), nil
 	}
 
-	vmlogger.Debugf("(%s) %x gas: %v (d) %x\n", self.Fn, closure.Address(), closure.Gas, closure.Args)
-
 	var (
 		op OpCode
 
-		mem      = &Memory{}
-		stack    = NewStack()
-		pc       = big.NewInt(0)
-		step     = 0
-		prevStep = 0
-		require  = func(m int) {
+		mem     = &Memory{}
+		stack   = NewStack()
+		pc      = 0
+		step    = 0
+		require = func(m int) {
 			if stack.Len() < m {
 				panic(fmt.Sprintf("%04v (%v) stack err size = %d, required = %d", pc, op, stack.Len(), m))
 			}
@@ -124,40 +54,16 @@ func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 	)
 
 	for {
-		prevStep = step
 		// The base for all big integer arithmetic
 		base := new(big.Int)
 
 		step++
 		// Get the memory location of pc
-		val := closure.Get(pc)
-		// Get the opcode (it must be an opcode!)
-		op = OpCode(val.Uint())
-
-		// XXX Leave this Println intact. Don't change this to the log system.
-		// Used for creating diffs between implementations
-		if self.logTy == LogTyDiff {
-			switch op {
-			case STOP, RETURN, SUICIDE:
-				closure.object.EachStorage(func(key string, value *ethutil.Value) {
-					value.Decode()
-					fmt.Printf("%x %x\n", new(big.Int).SetBytes([]byte(key)).Bytes(), value.Bytes())
-				})
-			}
-
-			b := pc.Bytes()
-			if len(b) == 0 {
-				b = []byte{0}
-			}
-
-			fmt.Printf("%x %x %x %x\n", closure.Address(), b, []byte{byte(op)}, closure.Gas.Bytes())
-		}
+		op := closure.GetOp(pc)
 
 		gas := new(big.Int)
 		addStepGasUsage := func(amount *big.Int) {
-			if amount.Cmp(ethutil.Big0) >= 0 {
-				gas.Add(gas, amount)
-			}
+			gas.Add(gas, amount)
 		}
 
 		addStepGasUsage(GasStep)
@@ -254,56 +160,43 @@ func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 			return closure.Return(nil), err
 		}
 
-		self.Printf("(pc) %-3d -o- %-14s", pc, op.String())
-		self.Printf(" (g) %-3v (%v)", gas, closure.Gas)
-
 		mem.Resize(newMemSize.Uint64())
 
 		switch op {
-		case LOG:
-			stack.Print()
-			mem.Print()
-			// 0x20 range
+		// 0x20 range
 		case ADD:
 			require(2)
 			x, y := stack.Popn()
-			self.Printf(" %v + %v", y, x)
 
 			base.Add(y, x)
 
 			To256(base)
 
-			self.Printf(" = %v", base)
 			// Pop result back on the stack
 			stack.Push(base)
 		case SUB:
 			require(2)
 			x, y := stack.Popn()
-			self.Printf(" %v - %v", y, x)
 
 			base.Sub(y, x)
 
 			To256(base)
 
-			self.Printf(" = %v", base)
 			// Pop result back on the stack
 			stack.Push(base)
 		case MUL:
 			require(2)
 			x, y := stack.Popn()
-			self.Printf(" %v * %v", y, x)
 
 			base.Mul(y, x)
 
 			To256(base)
 
-			self.Printf(" = %v", base)
 			// Pop result back on the stack
 			stack.Push(base)
 		case DIV:
 			require(2)
 			x, y := stack.Popn()
-			self.Printf(" %v / %v", y, x)
 
 			if x.Cmp(ethutil.Big0) != 0 {
 				base.Div(y, x)
@@ -311,13 +204,11 @@ func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 
 			To256(base)
 
-			self.Printf(" = %v", base)
 			// Pop result back on the stack
 			stack.Push(base)
 		case SDIV:
 			require(2)
 			x, y := stack.Popn()
-			self.Printf(" %v / %v", y, x)
 
 			if x.Cmp(ethutil.Big0) != 0 {
 				base.Div(y, x)
@@ -325,46 +216,35 @@ func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 
 			To256(base)
 
-			self.Printf(" = %v", base)
 			// Pop result back on the stack
 			stack.Push(base)
 		case MOD:
 			require(2)
 			x, y := stack.Popn()
 
-			self.Printf(" %v %% %v", y, x)
-
 			base.Mod(y, x)
 
 			To256(base)
 
-			self.Printf(" = %v", base)
 			stack.Push(base)
 		case SMOD:
 			require(2)
 			x, y := stack.Popn()
 
-			self.Printf(" %v %% %v", y, x)
-
 			base.Mod(y, x)
 
 			To256(base)
 
-			self.Printf(" = %v", base)
 			stack.Push(base)
 
 		case EXP:
 			require(2)
 			x, y := stack.Popn()
 
-			self.Printf(" %v ** %v", y, x)
-
 			base.Exp(y, x, Pow256)
 
 			To256(base)
 
-			self.Printf(" = %v", base)
-
 			stack.Push(base)
 		case NEG:
 			require(1)
@@ -373,7 +253,6 @@ func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 		case LT:
 			require(2)
 			x, y := stack.Popn()
-			self.Printf(" %v < %v", y, x)
 			// x < y
 			if y.Cmp(x) < 0 {
 				stack.Push(ethutil.BigTrue)
@@ -383,7 +262,6 @@ func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 		case GT:
 			require(2)
 			x, y := stack.Popn()
-			self.Printf(" %v > %v", y, x)
 
 			// x > y
 			if y.Cmp(x) > 0 {
@@ -395,7 +273,6 @@ func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 		case SLT:
 			require(2)
 			x, y := stack.Popn()
-			self.Printf(" %v < %v", y, x)
 			// x < y
 			if y.Cmp(x) < 0 {
 				stack.Push(ethutil.BigTrue)
@@ -405,7 +282,6 @@ func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 		case SGT:
 			require(2)
 			x, y := stack.Popn()
-			self.Printf(" %v > %v", y, x)
 
 			// x > y
 			if y.Cmp(x) > 0 {
@@ -417,7 +293,6 @@ func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 		case EQ:
 			require(2)
 			x, y := stack.Popn()
-			self.Printf(" %v == %v", y, x)
 
 			// x == y
 			if x.Cmp(y) == 0 {
@@ -438,19 +313,16 @@ func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 		case AND:
 			require(2)
 			x, y := stack.Popn()
-			self.Printf(" %v & %v", y, x)
 
 			stack.Push(base.And(y, x))
 		case OR:
 			require(2)
 			x, y := stack.Popn()
-			self.Printf(" %v | %v", y, x)
 
 			stack.Push(base.Or(y, x))
 		case XOR:
 			require(2)
 			x, y := stack.Popn()
-			self.Printf(" %v ^ %v", y, x)
 
 			stack.Push(base.Xor(y, x))
 		case BYTE:
@@ -460,7 +332,6 @@ func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 				byt := big.NewInt(int64(ethutil.LeftPadBytes(val.Bytes(), 32)[th.Int64()]))
 				stack.Push(byt)
 
-				self.Printf(" => 0x%x", byt.Bytes())
 			} else {
 				stack.Push(ethutil.BigFalse)
 			}
@@ -476,8 +347,6 @@ func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 
 			To256(base)
 
-			self.Printf(" = %v", base)
-
 			stack.Push(base)
 		case MULMOD:
 			require(3)
@@ -491,8 +360,6 @@ func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 
 			To256(base)
 
-			self.Printf(" = %v", base)
-
 			stack.Push(base)
 
 			// 0x20 range
@@ -503,12 +370,10 @@ func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 
 			stack.Push(ethutil.BigD(data))
 
-			self.Printf(" => %x", data)
 			// 0x30 range
 		case ADDRESS:
 			stack.Push(ethutil.BigD(closure.Address()))
 
-			self.Printf(" => %x", closure.Address())
 		case BALANCE:
 			require(1)
 
@@ -517,24 +382,20 @@ func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 
 			stack.Push(balance)
 
-			self.Printf(" => %v (%x)", balance, addr)
 		case ORIGIN:
 			origin := self.env.Origin()
 
 			stack.Push(ethutil.BigD(origin))
 
-			self.Printf(" => %x", origin)
 		case CALLER:
 			caller := closure.caller.Address()
 			stack.Push(ethutil.BigD(caller))
 
-			self.Printf(" => %x", caller)
 		case CALLVALUE:
 			value := self.env.Value()
 
 			stack.Push(value)
 
-			self.Printf(" => %v", value)
 		case CALLDATALOAD:
 			require(1)
 			var (
@@ -550,14 +411,11 @@ func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 				copy(data, closure.Args[offset.Int64():length.Int64()])
 			}
 
-			self.Printf(" => 0x%x", data)
-
 			stack.Push(ethutil.BigD(data))
 		case CALLDATASIZE:
 			l := int64(len(closure.Args))
 			stack.Push(big.NewInt(l))
 
-			self.Printf(" => %d", l)
 		case CALLDATACOPY:
 			var (
 				size = int64(len(closure.Args))
@@ -589,7 +447,6 @@ func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 			l := big.NewInt(int64(len(code)))
 			stack.Push(l)
 
-			self.Printf(" => %d", l)
 		case CODECOPY, EXTCODECOPY:
 			var code []byte
 			if op == EXTCODECOPY {
@@ -620,87 +477,68 @@ func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 		case GASPRICE:
 			stack.Push(closure.Price)
 
-			self.Printf(" => %v", closure.Price)
-
 			// 0x40 range
 		case PREVHASH:
 			prevHash := self.env.PrevHash()
 
 			stack.Push(ethutil.BigD(prevHash))
 
-			self.Printf(" => 0x%x", prevHash)
 		case COINBASE:
 			coinbase := self.env.Coinbase()
 
 			stack.Push(ethutil.BigD(coinbase))
 
-			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(number)
 
-			self.Printf(" => 0x%x", number.Bytes())
 		case DIFFICULTY:
 			difficulty := self.env.Difficulty()
 
 			stack.Push(difficulty)
 
-			self.Printf(" => 0x%x", difficulty.Bytes())
 		case GASLIMIT:
 			// TODO
 			stack.Push(big.NewInt(0))
 
 			// 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) - int64(PUSH1) + 1)
-			pc.Add(pc, ethutil.Big1)
-			data := closure.Gets(pc, a)
-			val := ethutil.BigD(data.Bytes())
+			a := int(op - PUSH1 + 1)
+			val := ethutil.BigD(closure.GetBytes(int(pc+1), a))
 			// Push value to stack
 			stack.Push(val)
-			pc.Add(pc, a.Sub(a, big.NewInt(1)))
 
-			step += int(op) - int(PUSH1) + 1
+			pc += a
 
-			self.Printf(" => 0x%x", data.Bytes())
+			step += int(op) - int(PUSH1) + 1
 		case POP:
 			require(1)
 			stack.Pop()
 		case DUP1, DUP2, DUP3, DUP4, DUP5, DUP6, DUP7, DUP8, DUP9, DUP10, DUP11, DUP12, DUP13, DUP14, DUP15, DUP16:
 			n := int(op - DUP1 + 1)
-			v := stack.Dupn(n)
-
-			self.Printf(" => [%d] 0x%x", n, stack.Peek().Bytes())
-
-			if OpCode(closure.Get(new(big.Int).Add(pc, ethutil.Big1)).Uint()) == POP && OpCode(closure.Get(new(big.Int).Add(pc, big.NewInt(2))).Uint()) == POP {
-				fmt.Println(toValue(v))
-			}
+			stack.Dupn(n)
 		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.Swapn(n)
 
-			self.Printf(" => [%d] %x [0] %x", n, x.Bytes(), y.Bytes())
 		case MLOAD:
 			require(1)
 			offset := stack.Pop()
 			val := ethutil.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
 			require(2)
 			// Pop value of the stack
 			val, mStart := stack.Popn()
 			mem.Set(mStart.Int64(), 32, ethutil.BigToBytes(val, 256))
 
-			self.Printf(" => 0x%x", val)
 		case MSTORE8:
 			require(2)
 			off := stack.Pop()
@@ -708,7 +546,6 @@ func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 
 			mem.store[off.Int64()] = byte(val.Int64() & 0xff)
 
-			self.Printf(" => [%v] 0x%x", off, val)
 		case SLOAD:
 			require(1)
 			loc := stack.Pop()
@@ -716,7 +553,6 @@ func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 
 			stack.Push(val.BigInt())
 
-			self.Printf(" {0x%x : 0x%x}", loc.Bytes(), val.Bytes())
 		case SSTORE:
 			require(2)
 			val, loc := stack.Popn()
@@ -724,32 +560,27 @@ func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 
 			closure.message.AddStorageChange(loc.Bytes())
 
-			self.Printf(" {0x%x : 0x%x}", loc.Bytes(), val.Bytes())
 		case JUMP:
 			require(1)
-			pc = stack.Pop()
+			pc = int(stack.Pop().Int64())
 			// Reduce pc by one because of the increment that's at the end of this for loop
-			self.Printf(" ~> %v", pc).Endl()
 
 			continue
 		case JUMPI:
 			require(2)
 			cond, pos := stack.Popn()
 			if cond.Cmp(ethutil.BigTrue) >= 0 {
-				pc = pos
+				pc = int(pos.Int64())
 
-				if OpCode(closure.Get(pc).Uint()) != JUMPDEST {
+				if closure.GetOp(int(pc)) != JUMPDEST {
 					return closure.Return(nil), fmt.Errorf("JUMP missed JUMPDEST %v", pc)
 				}
 
 				continue
-			} else {
-				self.Printf(" (f)")
 			}
 		case JUMPDEST:
-			self.Printf(" ~> %v (t)", pc).Endl()
 		case PC:
-			stack.Push(pc)
+			stack.Push(u256(int64(pc)))
 		case MSIZE:
 			stack.Push(big.NewInt(int64(mem.Len())))
 		case GAS:
@@ -774,8 +605,6 @@ func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 			addr := ethcrypto.CreateAddress(closure.Address(), closure.object.Nonce)
 			closure.object.Nonce++
 
-			self.Printf(" (*) %x", addr).Endl()
-
 			closure.UseGas(closure.Gas)
 
 			msg := NewExecution(self, addr, input, gas, closure.Price, value)
@@ -786,24 +615,15 @@ func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 				// Revert the state as it was before.
 				//self.env.State().Set(snapshot)
 
-				self.Printf("CREATE err %v", err)
 			} else {
 				msg.object.Code = ret
 
 				stack.Push(ethutil.BigD(addr))
 			}
 
-			self.Endl()
-
-			// Debug hook
-			if self.Dbg != nil {
-				self.Dbg.SetCode(closure.Code)
-			}
 		case CALL, CALLCODE:
 			require(7)
 
-			self.Endl()
-
 			gas := stack.Pop()
 			// Pop gas and value of the stack.
 			value, addr := stack.Popn()
@@ -836,18 +656,11 @@ func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 				mem.Set(retOffset.Int64(), retSize.Int64(), ret)
 			}
 
-			// Debug hook
-			if self.Dbg != nil {
-				self.Dbg.SetCode(closure.Code)
-			}
-
 		case RETURN:
 			require(2)
 			size, offset := stack.Popn()
 			ret := mem.Get(offset.Int64(), size.Int64())
 
-			self.Printf(" => (%d) 0x%x", len(ret), ret).Endl()
-
 			return closure.Return(ret), nil
 		case SUICIDE:
 			require(1)
@@ -860,7 +673,6 @@ func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 
 			fallthrough
 		case STOP: // Stop the closure
-			self.Endl()
 
 			return closure.Return(nil), nil
 		default:
@@ -871,121 +683,14 @@ func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 			return closure.Return(nil), fmt.Errorf("Invalid opcode %x", op)
 		}
 
-		pc.Add(pc, ethutil.Big1)
-
-		self.Endl()
-
-		if self.Dbg != nil {
-			for _, instrNo := range self.Dbg.BreakPoints() {
-				if pc.Cmp(big.NewInt(instrNo)) == 0 {
-					self.Stepping = true
-
-					if !self.Dbg.BreakHook(prevStep, op, mem, stack, closure.Object()) {
-						return nil, nil
-					}
-				} else if self.Stepping {
-					if !self.Dbg.StepHook(prevStep, op, mem, stack, closure.Object()) {
-						return nil, nil
-					}
-				}
-			}
-		}
-
+		pc++
 	}
 }
 
-func (self *Vm) Printf(format string, v ...interface{}) *Vm {
-	if self.Verbose && self.logTy == LogTyPretty {
-		self.logStr += fmt.Sprintf(format, v...)
-	}
-
-	return self
+func (self *Vm) Env() Environment {
+	return self.env
 }
 
-func (self *Vm) Endl() *Vm {
-	if self.Verbose && self.logTy == LogTyPretty {
-		vmlogger.Debugln(self.logStr)
-		self.logStr = ""
-	}
-
-	return self
-}
-
-type Execution struct {
-	vm                *Vm
-	closure           *Closure
-	address, input    []byte
-	gas, price, value *big.Int
-	object            *ethstate.StateObject
-}
-
-func NewExecution(vm *Vm, address, input []byte, gas, gasPrice, value *big.Int) *Execution {
-	return &Execution{vm: vm, address: address, input: input, gas: gas, price: gasPrice, value: value}
-}
-
-func (self *Execution) Addr() []byte {
-	return self.address
-}
-
-func (self *Execution) Exec(codeAddr []byte, caller ClosureRef) (ret []byte, err error) {
-	snapshot := self.vm.env.State().Copy()
-
-	msg := self.vm.env.State().Manifest().AddMessage(&ethstate.Message{
-		To: self.address, From: caller.Address(),
-		Input:  self.input,
-		Origin: self.vm.env.Origin(),
-		Block:  self.vm.env.BlockHash(), Timestamp: self.vm.env.Time(), Coinbase: self.vm.env.Coinbase(), Number: self.vm.env.BlockNumber(),
-		Value: self.value,
-	})
-
-	object := caller.Object()
-	if object.Balance.Cmp(self.value) < 0 {
-		caller.ReturnGas(self.gas, self.price)
-
-		err = fmt.Errorf("Insufficient funds to transfer value. Req %v, has %v", self.value, object.Balance)
-	} else {
-		stateObject := self.vm.env.State().GetOrNewStateObject(self.address)
-		self.object = stateObject
-
-		caller.Object().SubAmount(self.value)
-		stateObject.AddAmount(self.value)
-
-		// Precompiled contracts (address.go) 1, 2 & 3.
-		if p := Precompiled[ethutil.BigD(codeAddr).Uint64()]; p != nil {
-			if self.gas.Cmp(p.Gas) >= 0 {
-				ret = p.Call(self.input)
-			}
-		} else {
-			if self.vm.depth == MaxCallDepth {
-				return nil, fmt.Errorf("Max call depth exceeded (%d)", MaxCallDepth)
-			}
-
-			// Retrieve the executing code
-			code := self.vm.env.State().GetCode(codeAddr)
-
-			// Create a new callable closure
-			c := NewClosure(msg, caller, stateObject, code, self.gas, self.price)
-			// Executer the closure and get the return value (if any)
-			ret, _, err = c.Call(self.vm, self.input)
-
-			msg.Output = ret
-		}
-	}
-
-	if err != nil {
-		self.vm.env.State().Set(snapshot)
-	}
-
-	return
-}
-
-// Mainly used for print variables and passing to Print*
-func toValue(val *big.Int) interface{} {
-	// Let's assume a string on right padded zero's
-	b := val.Bytes()
-	if b[0] != 0 && b[len(b)-1] == 0x0 && b[len(b)-2] == 0x0 {
-		return string(b)
-	}
-
-	return val
+func (self *Vm) Depth() int {
+	return self.depth
 }
diff --git a/ethvm/vm_debug.go b/ethvm/vm_debug.go
new file mode 100644
index 000000000..8892ed6b8
--- /dev/null
+++ b/ethvm/vm_debug.go
@@ -0,0 +1,872 @@
+package ethvm
+
+import (
+	"fmt"
+	"math/big"
+
+	"github.com/ethereum/eth-go/ethcrypto"
+	"github.com/ethereum/eth-go/ethutil"
+)
+
+type DebugVm struct {
+	env Environment
+
+	logTy  byte
+	logStr string
+
+	err error
+
+	// Debugging
+	Dbg Debugger
+
+	BreakPoints []int64
+	Stepping    bool
+	Fn          string
+
+	Recoverable bool
+
+	depth int
+}
+
+func NewDebugVm(env Environment) *DebugVm {
+	lt := LogTyPretty
+	if ethutil.Config.Diff {
+		lt = LogTyDiff
+	}
+
+	return &DebugVm{env: env, logTy: lt, Recoverable: true}
+}
+
+func (self *DebugVm) RunClosure(closure *Closure) (ret []byte, err error) {
+	self.depth++
+
+	if self.Recoverable {
+		// Recover from any require exception
+		defer func() {
+			if r := recover(); r != nil {
+				ret = closure.Return(nil)
+				err = fmt.Errorf("%v", r)
+			}
+		}()
+	}
+
+	// Debug hook
+	if self.Dbg != nil {
+		self.Dbg.SetCode(closure.Code)
+	}
+
+	// Don't bother with the execution if there's no code.
+	if len(closure.Code) == 0 {
+		return closure.Return(nil), nil
+	}
+
+	vmlogger.Debugf("(%s) %x gas: %v (d) %x\n", self.Fn, closure.Address(), closure.Gas, closure.Args)
+
+	var (
+		op OpCode
+
+		mem      = &Memory{}
+		stack    = NewStack()
+		pc       = big.NewInt(0)
+		step     = 0
+		prevStep = 0
+		require  = func(m int) {
+			if stack.Len() < m {
+				panic(fmt.Sprintf("%04v (%v) stack err size = %d, required = %d", pc, op, stack.Len(), m))
+			}
+		}
+	)
+
+	for {
+		prevStep = step
+		// The base for all big integer arithmetic
+		base := new(big.Int)
+
+		step++
+		// Get the memory location of pc
+		op := OpCode(closure.Get(pc).Uint())
+
+		// XXX Leave this Println intact. Don't change this to the log system.
+		// Used for creating diffs between implementations
+		if self.logTy == LogTyDiff {
+			switch op {
+			case STOP, RETURN, SUICIDE:
+				closure.object.EachStorage(func(key string, value *ethutil.Value) {
+					value.Decode()
+					fmt.Printf("%x %x\n", new(big.Int).SetBytes([]byte(key)).Bytes(), value.Bytes())
+				})
+			}
+
+			b := pc.Bytes()
+			if len(b) == 0 {
+				b = []byte{0}
+			}
+
+			fmt.Printf("%x %x %x %x\n", closure.Address(), b, []byte{byte(op)}, closure.Gas.Bytes())
+		}
+
+		gas := new(big.Int)
+		addStepGasUsage := func(amount *big.Int) {
+			if amount.Cmp(ethutil.Big0) >= 0 {
+				gas.Add(gas, amount)
+			}
+		}
+
+		addStepGasUsage(GasStep)
+
+		var newMemSize *big.Int = ethutil.Big0
+		switch op {
+		case STOP:
+			gas.Set(ethutil.Big0)
+		case SUICIDE:
+			gas.Set(ethutil.Big0)
+		case SLOAD:
+			gas.Set(GasSLoad)
+		case SSTORE:
+			var mult *big.Int
+			y, x := stack.Peekn()
+			val := closure.GetStorage(x)
+			if val.BigInt().Cmp(ethutil.Big0) == 0 && len(y.Bytes()) > 0 {
+				mult = ethutil.Big2
+			} else if val.BigInt().Cmp(ethutil.Big0) != 0 && len(y.Bytes()) == 0 {
+				mult = ethutil.Big0
+			} else {
+				mult = ethutil.Big1
+			}
+			gas = new(big.Int).Mul(mult, GasSStore)
+		case BALANCE:
+			gas.Set(GasBalance)
+		case MSTORE:
+			require(2)
+			newMemSize = calcMemSize(stack.Peek(), u256(32))
+		case MLOAD:
+			require(1)
+
+			newMemSize = calcMemSize(stack.Peek(), u256(32))
+		case MSTORE8:
+			require(2)
+			newMemSize = calcMemSize(stack.Peek(), u256(1))
+		case RETURN:
+			require(2)
+
+			newMemSize = calcMemSize(stack.Peek(), stack.data[stack.Len()-2])
+		case SHA3:
+			require(2)
+
+			gas.Set(GasSha)
+
+			newMemSize = calcMemSize(stack.Peek(), stack.data[stack.Len()-2])
+		case CALLDATACOPY:
+			require(2)
+
+			newMemSize = calcMemSize(stack.Peek(), stack.data[stack.Len()-3])
+		case CODECOPY:
+			require(3)
+
+			newMemSize = calcMemSize(stack.Peek(), stack.data[stack.Len()-3])
+		case EXTCODECOPY:
+			require(4)
+
+			newMemSize = calcMemSize(stack.data[stack.Len()-2], stack.data[stack.Len()-4])
+		case CALL, CALLCODE:
+			require(7)
+			gas.Set(GasCall)
+			addStepGasUsage(stack.data[stack.Len()-1])
+
+			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)
+		case CREATE:
+			require(3)
+			gas.Set(GasCreate)
+
+			newMemSize = calcMemSize(stack.data[stack.Len()-2], stack.data[stack.Len()-3])
+		}
+
+		if newMemSize.Cmp(ethutil.Big0) > 0 {
+			newMemSize.Add(newMemSize, u256(31))
+			newMemSize.Div(newMemSize, u256(32))
+			newMemSize.Mul(newMemSize, u256(32))
+
+			if newMemSize.Cmp(u256(int64(mem.Len()))) > 0 {
+				memGasUsage := new(big.Int).Sub(newMemSize, u256(int64(mem.Len())))
+				memGasUsage.Mul(GasMemory, memGasUsage)
+				memGasUsage.Div(memGasUsage, u256(32))
+
+				addStepGasUsage(memGasUsage)
+			}
+		}
+
+		if !closure.UseGas(gas) {
+			err := fmt.Errorf("Insufficient gas for %v. req %v has %v", op, gas, closure.Gas)
+
+			closure.UseGas(closure.Gas)
+
+			return closure.Return(nil), err
+		}
+
+		self.Printf("(pc) %-3d -o- %-14s", pc, op.String())
+		self.Printf(" (g) %-3v (%v)", gas, closure.Gas)
+
+		mem.Resize(newMemSize.Uint64())
+
+		switch op {
+		case LOG:
+			stack.Print()
+			mem.Print()
+			// 0x20 range
+		case ADD:
+			require(2)
+			x, y := stack.Popn()
+			self.Printf(" %v + %v", y, x)
+
+			base.Add(y, x)
+
+			To256(base)
+
+			self.Printf(" = %v", base)
+			// Pop result back on the stack
+			stack.Push(base)
+		case SUB:
+			require(2)
+			x, y := stack.Popn()
+			self.Printf(" %v - %v", y, x)
+
+			base.Sub(y, x)
+
+			To256(base)
+
+			self.Printf(" = %v", base)
+			// Pop result back on the stack
+			stack.Push(base)
+		case MUL:
+			require(2)
+			x, y := stack.Popn()
+			self.Printf(" %v * %v", y, x)
+
+			base.Mul(y, x)
+
+			To256(base)
+
+			self.Printf(" = %v", base)
+			// Pop result back on the stack
+			stack.Push(base)
+		case DIV:
+			require(2)
+			x, y := stack.Popn()
+			self.Printf(" %v / %v", y, x)
+
+			if x.Cmp(ethutil.Big0) != 0 {
+				base.Div(y, x)
+			}
+
+			To256(base)
+
+			self.Printf(" = %v", base)
+			// Pop result back on the stack
+			stack.Push(base)
+		case SDIV:
+			require(2)
+			x, y := stack.Popn()
+			self.Printf(" %v / %v", y, x)
+
+			if x.Cmp(ethutil.Big0) != 0 {
+				base.Div(y, x)
+			}
+
+			To256(base)
+
+			self.Printf(" = %v", base)
+			// Pop result back on the stack
+			stack.Push(base)
+		case MOD:
+			require(2)
+			x, y := stack.Popn()
+
+			self.Printf(" %v %% %v", y, x)
+
+			base.Mod(y, x)
+
+			To256(base)
+
+			self.Printf(" = %v", base)
+			stack.Push(base)
+		case SMOD:
+			require(2)
+			x, y := stack.Popn()
+
+			self.Printf(" %v %% %v", y, x)
+
+			base.Mod(y, x)
+
+			To256(base)
+
+			self.Printf(" = %v", base)
+			stack.Push(base)
+
+		case EXP:
+			require(2)
+			x, y := stack.Popn()
+
+			self.Printf(" %v ** %v", y, x)
+
+			base.Exp(y, x, Pow256)
+
+			To256(base)
+
+			self.Printf(" = %v", base)
+
+			stack.Push(base)
+		case NEG:
+			require(1)
+			base.Sub(Pow256, stack.Pop())
+			stack.Push(base)
+		case LT:
+			require(2)
+			x, y := stack.Popn()
+			self.Printf(" %v < %v", y, x)
+			// x < y
+			if y.Cmp(x) < 0 {
+				stack.Push(ethutil.BigTrue)
+			} else {
+				stack.Push(ethutil.BigFalse)
+			}
+		case GT:
+			require(2)
+			x, y := stack.Popn()
+			self.Printf(" %v > %v", y, x)
+
+			// x > y
+			if y.Cmp(x) > 0 {
+				stack.Push(ethutil.BigTrue)
+			} else {
+				stack.Push(ethutil.BigFalse)
+			}
+
+		case SLT:
+			require(2)
+			x, y := stack.Popn()
+			self.Printf(" %v < %v", y, x)
+			// x < y
+			if y.Cmp(x) < 0 {
+				stack.Push(ethutil.BigTrue)
+			} else {
+				stack.Push(ethutil.BigFalse)
+			}
+		case SGT:
+			require(2)
+			x, y := stack.Popn()
+			self.Printf(" %v > %v", y, x)
+
+			// x > y
+			if y.Cmp(x) > 0 {
+				stack.Push(ethutil.BigTrue)
+			} else {
+				stack.Push(ethutil.BigFalse)
+			}
+
+		case EQ:
+			require(2)
+			x, y := stack.Popn()
+			self.Printf(" %v == %v", y, x)
+
+			// x == y
+			if x.Cmp(y) == 0 {
+				stack.Push(ethutil.BigTrue)
+			} else {
+				stack.Push(ethutil.BigFalse)
+			}
+		case NOT:
+			require(1)
+			x := stack.Pop()
+			if x.Cmp(ethutil.BigFalse) > 0 {
+				stack.Push(ethutil.BigFalse)
+			} else {
+				stack.Push(ethutil.BigTrue)
+			}
+
+			// 0x10 range
+		case AND:
+			require(2)
+			x, y := stack.Popn()
+			self.Printf(" %v & %v", y, x)
+
+			stack.Push(base.And(y, x))
+		case OR:
+			require(2)
+			x, y := stack.Popn()
+			self.Printf(" %v | %v", y, x)
+
+			stack.Push(base.Or(y, x))
+		case XOR:
+			require(2)
+			x, y := stack.Popn()
+			self.Printf(" %v ^ %v", y, x)
+
+			stack.Push(base.Xor(y, x))
+		case BYTE:
+			require(2)
+			val, th := stack.Popn()
+			if th.Cmp(big.NewInt(32)) < 0 && th.Cmp(big.NewInt(int64(len(val.Bytes())))) < 0 {
+				byt := big.NewInt(int64(ethutil.LeftPadBytes(val.Bytes(), 32)[th.Int64()]))
+				stack.Push(byt)
+
+				self.Printf(" => 0x%x", byt.Bytes())
+			} else {
+				stack.Push(ethutil.BigFalse)
+			}
+		case ADDMOD:
+			require(3)
+
+			x := stack.Pop()
+			y := stack.Pop()
+			z := stack.Pop()
+
+			base.Add(x, y)
+			base.Mod(base, z)
+
+			To256(base)
+
+			self.Printf(" = %v", base)
+
+			stack.Push(base)
+		case MULMOD:
+			require(3)
+
+			x := stack.Pop()
+			y := stack.Pop()
+			z := stack.Pop()
+
+			base.Mul(x, y)
+			base.Mod(base, z)
+
+			To256(base)
+
+			self.Printf(" = %v", base)
+
+			stack.Push(base)
+
+			// 0x20 range
+		case SHA3:
+			require(2)
+			size, offset := stack.Popn()
+			data := ethcrypto.Sha3(mem.Get(offset.Int64(), size.Int64()))
+
+			stack.Push(ethutil.BigD(data))
+
+			self.Printf(" => %x", data)
+			// 0x30 range
+		case ADDRESS:
+			stack.Push(ethutil.BigD(closure.Address()))
+
+			self.Printf(" => %x", closure.Address())
+		case BALANCE:
+			require(1)
+
+			addr := stack.Pop().Bytes()
+			balance := self.env.State().GetBalance(addr)
+
+			stack.Push(balance)
+
+			self.Printf(" => %v (%x)", balance, addr)
+		case ORIGIN:
+			origin := self.env.Origin()
+
+			stack.Push(ethutil.BigD(origin))
+
+			self.Printf(" => %x", origin)
+		case CALLER:
+			caller := closure.caller.Address()
+			stack.Push(ethutil.BigD(caller))
+
+			self.Printf(" => %x", caller)
+		case CALLVALUE:
+			value := self.env.Value()
+
+			stack.Push(value)
+
+			self.Printf(" => %v", value)
+		case CALLDATALOAD:
+			require(1)
+			var (
+				offset  = stack.Pop()
+				data    = make([]byte, 32)
+				lenData = big.NewInt(int64(len(closure.Args)))
+			)
+
+			if lenData.Cmp(offset) >= 0 {
+				length := new(big.Int).Add(offset, ethutil.Big32)
+				length = ethutil.BigMin(length, lenData)
+
+				copy(data, closure.Args[offset.Int64():length.Int64()])
+			}
+
+			self.Printf(" => 0x%x", data)
+
+			stack.Push(ethutil.BigD(data))
+		case CALLDATASIZE:
+			l := int64(len(closure.Args))
+			stack.Push(big.NewInt(l))
+
+			self.Printf(" => %d", l)
+		case CALLDATACOPY:
+			var (
+				size = int64(len(closure.Args))
+				mOff = stack.Pop().Int64()
+				cOff = stack.Pop().Int64()
+				l    = stack.Pop().Int64()
+			)
+
+			if cOff > size {
+				cOff = 0
+				l = 0
+			} else if cOff+l > size {
+				l = 0
+			}
+
+			code := closure.Args[cOff : cOff+l]
+
+			mem.Set(mOff, l, code)
+		case CODESIZE, EXTCODESIZE:
+			var code []byte
+			if op == EXTCODECOPY {
+				addr := stack.Pop().Bytes()
+
+				code = self.env.State().GetCode(addr)
+			} else {
+				code = closure.Code
+			}
+
+			l := big.NewInt(int64(len(code)))
+			stack.Push(l)
+
+			self.Printf(" => %d", l)
+		case CODECOPY, EXTCODECOPY:
+			var code []byte
+			if op == EXTCODECOPY {
+				addr := stack.Pop().Bytes()
+
+				code = self.env.State().GetCode(addr)
+			} else {
+				code = closure.Code
+			}
+
+			var (
+				size = int64(len(code))
+				mOff = stack.Pop().Int64()
+				cOff = stack.Pop().Int64()
+				l    = stack.Pop().Int64()
+			)
+
+			if cOff > size {
+				cOff = 0
+				l = 0
+			} else if cOff+l > size {
+				l = 0
+			}
+
+			codeCopy := code[cOff : cOff+l]
+
+			mem.Set(mOff, l, codeCopy)
+		case GASPRICE:
+			stack.Push(closure.Price)
+
+			self.Printf(" => %v", closure.Price)
+
+			// 0x40 range
+		case PREVHASH:
+			prevHash := self.env.PrevHash()
+
+			stack.Push(ethutil.BigD(prevHash))
+
+			self.Printf(" => 0x%x", prevHash)
+		case COINBASE:
+			coinbase := self.env.Coinbase()
+
+			stack.Push(ethutil.BigD(coinbase))
+
+			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(number)
+
+			self.Printf(" => 0x%x", number.Bytes())
+		case DIFFICULTY:
+			difficulty := self.env.Difficulty()
+
+			stack.Push(difficulty)
+
+			self.Printf(" => 0x%x", difficulty.Bytes())
+		case GASLIMIT:
+			// TODO
+			stack.Push(big.NewInt(0))
+
+			// 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) - int64(PUSH1) + 1)
+			pc.Add(pc, ethutil.Big1)
+			data := closure.Gets(pc, a)
+			val := ethutil.BigD(data.Bytes())
+			// Push value to stack
+			stack.Push(val)
+			pc.Add(pc, a.Sub(a, big.NewInt(1)))
+
+			step += int(op) - int(PUSH1) + 1
+
+			self.Printf(" => 0x%x", data.Bytes())
+		case POP:
+			require(1)
+			stack.Pop()
+		case DUP1, DUP2, DUP3, DUP4, DUP5, DUP6, DUP7, DUP8, DUP9, DUP10, DUP11, DUP12, DUP13, DUP14, DUP15, DUP16:
+			n := int(op - DUP1 + 1)
+			v := stack.Dupn(n)
+
+			self.Printf(" => [%d] 0x%x", n, stack.Peek().Bytes())
+
+			if OpCode(closure.Get(new(big.Int).Add(pc, ethutil.Big1)).Uint()) == POP && OpCode(closure.Get(new(big.Int).Add(pc, big.NewInt(2))).Uint()) == POP {
+				fmt.Println(toValue(v))
+			}
+		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)
+
+			self.Printf(" => [%d] %x [0] %x", n, x.Bytes(), y.Bytes())
+		case MLOAD:
+			require(1)
+			offset := stack.Pop()
+			val := ethutil.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
+			require(2)
+			// Pop value of the stack
+			val, mStart := stack.Popn()
+			mem.Set(mStart.Int64(), 32, ethutil.BigToBytes(val, 256))
+
+			self.Printf(" => 0x%x", val)
+		case MSTORE8:
+			require(2)
+			off := stack.Pop()
+			val := stack.Pop()
+
+			mem.store[off.Int64()] = byte(val.Int64() & 0xff)
+
+			self.Printf(" => [%v] 0x%x", off, val)
+		case SLOAD:
+			require(1)
+			loc := stack.Pop()
+			val := closure.GetStorage(loc)
+
+			stack.Push(val.BigInt())
+
+			self.Printf(" {0x%x : 0x%x}", loc.Bytes(), val.Bytes())
+		case SSTORE:
+			require(2)
+			val, loc := stack.Popn()
+			closure.SetStorage(loc, ethutil.NewValue(val))
+
+			closure.message.AddStorageChange(loc.Bytes())
+
+			self.Printf(" {0x%x : 0x%x}", loc.Bytes(), val.Bytes())
+		case JUMP:
+			require(1)
+			pc = stack.Pop()
+			// Reduce pc by one because of the increment that's at the end of this for loop
+			self.Printf(" ~> %v", pc).Endl()
+
+			continue
+		case JUMPI:
+			require(2)
+			cond, pos := stack.Popn()
+			if cond.Cmp(ethutil.BigTrue) >= 0 {
+				pc = pos
+
+				if OpCode(closure.Get(pc).Uint()) != JUMPDEST {
+					return closure.Return(nil), fmt.Errorf("JUMP missed JUMPDEST %v", pc)
+				}
+
+				continue
+			} else {
+				self.Printf(" (f)")
+			}
+		case JUMPDEST:
+			self.Printf(" ~> %v (t)", pc).Endl()
+		case PC:
+			stack.Push(pc)
+		case MSIZE:
+			stack.Push(big.NewInt(int64(mem.Len())))
+		case GAS:
+			stack.Push(closure.Gas)
+			// 0x60 range
+		case CREATE:
+			require(3)
+
+			var (
+				err          error
+				value        = stack.Pop()
+				size, offset = stack.Popn()
+				input        = mem.Get(offset.Int64(), size.Int64())
+				gas          = new(big.Int).Set(closure.Gas)
+
+				// Snapshot the current stack so we are able to
+				// revert back to it later.
+				//snapshot = self.env.State().Copy()
+			)
+
+			// Generate a new address
+			addr := ethcrypto.CreateAddress(closure.Address(), closure.object.Nonce)
+			closure.object.Nonce++
+
+			self.Printf(" (*) %x", addr).Endl()
+
+			closure.UseGas(closure.Gas)
+
+			msg := NewExecution(self, addr, input, gas, closure.Price, value)
+			ret, err := msg.Exec(addr, closure)
+			if err != nil {
+				stack.Push(ethutil.BigFalse)
+
+				// Revert the state as it was before.
+				//self.env.State().Set(snapshot)
+
+				self.Printf("CREATE err %v", err)
+			} else {
+				msg.object.Code = ret
+
+				stack.Push(ethutil.BigD(addr))
+			}
+
+			self.Endl()
+
+			// Debug hook
+			if self.Dbg != nil {
+				self.Dbg.SetCode(closure.Code)
+			}
+		case CALL, CALLCODE:
+			require(7)
+
+			self.Endl()
+
+			gas := stack.Pop()
+			// Pop gas and value of the stack.
+			value, addr := stack.Popn()
+			// Pop input size and offset
+			inSize, inOffset := stack.Popn()
+			// Pop return size and offset
+			retSize, retOffset := stack.Popn()
+
+			// Get the arguments from the memory
+			args := mem.Get(inOffset.Int64(), inSize.Int64())
+
+			//snapshot := self.env.State().Copy()
+
+			var executeAddr []byte
+			if op == CALLCODE {
+				executeAddr = closure.Address()
+			} else {
+				executeAddr = addr.Bytes()
+			}
+
+			msg := NewExecution(self, executeAddr, args, gas, closure.Price, value)
+			ret, err := msg.Exec(addr.Bytes(), closure)
+			if err != nil {
+				stack.Push(ethutil.BigFalse)
+
+				//self.env.State().Set(snapshot)
+			} else {
+				stack.Push(ethutil.BigTrue)
+
+				mem.Set(retOffset.Int64(), retSize.Int64(), ret)
+			}
+
+			// Debug hook
+			if self.Dbg != nil {
+				self.Dbg.SetCode(closure.Code)
+			}
+
+		case RETURN:
+			require(2)
+			size, offset := stack.Popn()
+			ret := mem.Get(offset.Int64(), size.Int64())
+
+			self.Printf(" => (%d) 0x%x", len(ret), ret).Endl()
+
+			return closure.Return(ret), nil
+		case SUICIDE:
+			require(1)
+
+			receiver := self.env.State().GetOrNewStateObject(stack.Pop().Bytes())
+
+			receiver.AddAmount(closure.object.Balance)
+
+			closure.object.MarkForDeletion()
+
+			fallthrough
+		case STOP: // Stop the closure
+			self.Endl()
+
+			return closure.Return(nil), nil
+		default:
+			vmlogger.Debugf("(pc) %-3v Invalid opcode %x\n", pc, op)
+
+			//panic(fmt.Sprintf("Invalid opcode %x", op))
+
+			return closure.Return(nil), fmt.Errorf("Invalid opcode %x", op)
+		}
+
+		pc.Add(pc, ethutil.Big1)
+
+		self.Endl()
+
+		if self.Dbg != nil {
+			for _, instrNo := range self.Dbg.BreakPoints() {
+				if pc.Cmp(big.NewInt(instrNo)) == 0 {
+					self.Stepping = true
+
+					if !self.Dbg.BreakHook(prevStep, op, mem, stack, closure.Object()) {
+						return nil, nil
+					}
+				} else if self.Stepping {
+					if !self.Dbg.StepHook(prevStep, op, mem, stack, closure.Object()) {
+						return nil, nil
+					}
+				}
+			}
+		}
+
+	}
+}
+
+func (self *DebugVm) Printf(format string, v ...interface{}) *DebugVm {
+	if self.logTy == LogTyPretty {
+		self.logStr += fmt.Sprintf(format, v...)
+	}
+
+	return self
+}
+
+func (self *DebugVm) Endl() *DebugVm {
+	if self.logTy == LogTyPretty {
+		vmlogger.Debugln(self.logStr)
+		self.logStr = ""
+	}
+
+	return self
+}
+
+func (self *DebugVm) Env() Environment {
+	return self.env
+}
+
+func (self *DebugVm) Depth() int {
+	return self.depth
+}
diff --git a/ethvm/vm_test.go b/ethvm/vm_test.go
index 5b3a9aef1..40fb985a6 100644
--- a/ethvm/vm_test.go
+++ b/ethvm/vm_test.go
@@ -2,9 +2,9 @@ package ethvm
 
 import (
 	"fmt"
+	"io/ioutil"
 	"log"
 	"math/big"
-	"os"
 	"testing"
 
 	"github.com/ethereum/eth-go/ethlog"
@@ -17,6 +17,7 @@ type TestEnv struct {
 
 func (self TestEnv) Origin() []byte         { return nil }
 func (self TestEnv) BlockNumber() *big.Int  { return nil }
+func (self TestEnv) BlockHash() []byte      { return nil }
 func (self TestEnv) PrevHash() []byte       { return nil }
 func (self TestEnv) Coinbase() []byte       { return nil }
 func (self TestEnv) Time() int64            { return 0 }
@@ -24,20 +25,65 @@ func (self TestEnv) Difficulty() *big.Int   { return nil }
 func (self TestEnv) Value() *big.Int        { return nil }
 func (self TestEnv) State() *ethstate.State { return nil }
 
-func TestVm(t *testing.T) {
-	ethlog.AddLogSystem(ethlog.NewStdLogSystem(os.Stdout, log.LstdFlags, ethlog.LogLevel(4)))
+func setup(level int, typ Type) (*Closure, VirtualMachine) {
+	// Pipe output to /dev/null
+	ethlog.AddLogSystem(ethlog.NewStdLogSystem(ioutil.Discard, log.LstdFlags, ethlog.LogLevel(level)))
 
 	ethutil.ReadConfig(".ethtest", "/tmp/ethtest", "")
 
 	stateObject := ethstate.NewStateObject([]byte{'j', 'e', 'f', 'f'})
-	callerClosure := NewClosure(stateObject, stateObject, []byte{0x60, 0x01}, big.NewInt(1000000), big.NewInt(0))
+	callerClosure := NewClosure(nil, stateObject, stateObject, []byte{
+		PUSH1, 1,
+		PUSH1, 0,
+		MSTORE,
+		PUSH1, 32,
+		PUSH1, 0,
+		RETURN,
+	}, big.NewInt(1000000), big.NewInt(0))
 
-	vm := New(TestEnv{})
-	vm.Verbose = true
+	return callerClosure, New(TestEnv{}, typ)
+}
 
-	ret, _, e := callerClosure.Call(vm, nil)
+func TestDebugVm(t *testing.T) {
+	closure, vm := setup(4, DebugVmTy)
+	ret, _, e := closure.Call(vm, nil)
 	if e != nil {
 		fmt.Println("error", e)
 	}
-	fmt.Println(ret)
+
+	if ret[len(ret)-1] != 1 {
+		t.Errorf("Expected VM to return 1, got", ret, "instead.")
+	}
+}
+
+func TestVm(t *testing.T) {
+	closure, vm := setup(4, StandardVmTy)
+	ret, _, e := closure.Call(vm, nil)
+	if e != nil {
+		fmt.Println("error", e)
+	}
+
+	if ret[len(ret)-1] != 1 {
+		t.Errorf("Expected VM to return 1, got", ret, "instead.")
+	}
+}
+
+func BenchmarkDebugVm(b *testing.B) {
+	closure, vm := setup(3, DebugVmTy)
+
+	b.ResetTimer()
+
+	for i := 0; i < b.N; i++ {
+		closure.Call(vm, nil)
+	}
+}
+
+func BenchmarkVm(b *testing.B) {
+	closure, vm := setup(3, StandardVmTy)
+
+	b.ResetTimer()
+
+	for i := 0; i < b.N; i++ {
+		closure.Call(vm, nil)
+	}
 }