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.

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
+}