diff --git a/ethutil/big.go b/ethutil/big.go
index d4f6361e9a..2ff1c72d81 100644
--- a/ethutil/big.go
+++ b/ethutil/big.go
@@ -62,14 +62,14 @@ func S256(x *big.Int) *big.Int {
 	}
 }
 
-func FirstBitSet(v *big.Int) *big.Int {
+func FirstBitSet(v *big.Int) int {
 	for i := 0; i < v.BitLen(); i++ {
 		if v.Bit(i) > 0 {
-			return big.NewInt(int64(i))
+			return i
 		}
 	}
 
-	return big.NewInt(int64(v.BitLen()))
+	return v.BitLen()
 }
 
 // Big to bytes
diff --git a/tests/vm/gh_test.go b/tests/vm/gh_test.go
index bd107249b1..eb641b0343 100644
--- a/tests/vm/gh_test.go
+++ b/tests/vm/gh_test.go
@@ -2,7 +2,6 @@ package vm
 
 import (
 	"bytes"
-	"fmt"
 	"testing"
 
 	"github.com/ethereum/go-ethereum/ethutil"
@@ -45,7 +44,6 @@ func RunVmTest(p string, t *testing.T) {
 	helper.CreateFileTests(t, p, &tests)
 
 	for name, test := range tests {
-		fmt.Println(name)
 		state := state.New(helper.NewTrie())
 		for addr, account := range test.Pre {
 			obj := StateObjectFromAccount(addr, account)
@@ -85,20 +83,10 @@ func RunVmTest(p string, t *testing.T) {
 
 // I've created a new function for each tests so it's easier to identify where the problem lies if any of them fail.
 func TestVMArithmetic(t *testing.T) {
-	//helper.Logger.SetLogLevel(5)
 	const fn = "../files/vmtests/vmArithmeticTest.json"
 	RunVmTest(fn, t)
 }
 
-/*
-deleted?
-func TestVMSystemOperation(t *testing.T) {
-	helper.Logger.SetLogLevel(5)
-	const fn = "../files/vmtests/vmSystemOperationsTest.json"
-	RunVmTest(fn, t)
-}
-*/
-
 func TestBitwiseLogicOperation(t *testing.T) {
 	const fn = "../files/vmtests/vmBitwiseLogicOperationTest.json"
 	RunVmTest(fn, t)
@@ -126,7 +114,7 @@ func TestPushDupSwap(t *testing.T) {
 }
 
 func TestVMSha3(t *testing.T) {
-	helper.Logger.SetLogLevel(5)
+	//helper.Logger.SetLogLevel(5)
 	const fn = "../files/vmtests/vmSha3Test.json"
 	RunVmTest(fn, t)
 }
diff --git a/vm/vm_debug.go b/vm/vm_debug.go
index 4daa3ab5ba..ea94987d15 100644
--- a/vm/vm_debug.go
+++ b/vm/vm_debug.go
@@ -172,12 +172,13 @@ func (self *DebugVm) RunClosure(closure *Closure) (ret []byte, err error) {
 		case EXP:
 			require(2)
 
-			expGas := ethutil.FirstBitSet(stack.data[stack.Len()-2])
-			expGas.Div(expGas, u256(8))
-			expGas.Sub(u256(32), expGas)
-			expGas.Add(expGas, u256(1))
-
-			gas.Set(expGas)
+			exp := new(big.Int).Set(stack.data[stack.Len()-2])
+			nbytes := 0
+			for exp.Cmp(ethutil.Big0) > 0 {
+				nbytes += 1
+				exp.Rsh(exp, 8)
+			}
+			gas.Set(big.NewInt(int64(nbytes + 1)))
 		// Gas only
 		case STOP:
 			gas.Set(ethutil.Big0)