diff --git a/core/state/state_object.go b/core/state/state_object.go
index 1fdaec6147..fc26af68db 100644
--- a/core/state/state_object.go
+++ b/core/state/state_object.go
@@ -93,7 +93,7 @@ type stateObject struct {
 
 // empty returns whether the account is considered empty.
 func (s *stateObject) empty() bool {
-	return s.data.Nonce == 0 && s.data.Balance.Sign() == 0 && bytes.Equal(s.data.CodeHash, types.EmptyCodeHash.Bytes())
+	return s.data.Nonce == 0 && s.data.Balance.IsZero() && bytes.Equal(s.data.CodeHash, types.EmptyCodeHash.Bytes())
 }
 
 // newObject creates a state object.
@@ -408,7 +408,7 @@ func (s *stateObject) commit() (*trienode.NodeSet, error) {
 func (s *stateObject) AddBalance(amount *uint256.Int) {
 	// EIP161: We must check emptiness for the objects such that the account
 	// clearing (0,0,0 objects) can take effect.
-	if amount.Sign() == 0 {
+	if amount.IsZero() {
 		if s.empty() {
 			s.touch()
 		}
@@ -420,7 +420,7 @@ func (s *stateObject) AddBalance(amount *uint256.Int) {
 // SubBalance removes amount from s's balance.
 // It is used to remove funds from the origin account of a transfer.
 func (s *stateObject) SubBalance(amount *uint256.Int) {
-	if amount.Sign() == 0 {
+	if amount.IsZero() {
 		return
 	}
 	s.SetBalance(new(uint256.Int).Sub(s.Balance(), amount))
diff --git a/core/vm/evm.go b/core/vm/evm.go
index 985e6a9ae2..16cc854908 100644
--- a/core/vm/evm.go
+++ b/core/vm/evm.go
@@ -182,7 +182,7 @@ func (evm *EVM) Call(caller ContractRef, addr common.Address, input []byte, gas
 		return nil, gas, ErrDepth
 	}
 	// Fail if we're trying to transfer more than the available balance
-	if value.Sign() != 0 && !evm.Context.CanTransfer(evm.StateDB, caller.Address(), value) {
+	if !value.IsZero() && !evm.Context.CanTransfer(evm.StateDB, caller.Address(), value) {
 		return nil, gas, ErrInsufficientBalance
 	}
 	snapshot := evm.StateDB.Snapshot()
@@ -190,7 +190,7 @@ func (evm *EVM) Call(caller ContractRef, addr common.Address, input []byte, gas
 	debug := evm.Config.Tracer != nil
 
 	if !evm.StateDB.Exist(addr) {
-		if !isPrecompile && evm.chainRules.IsEIP158 && value.Sign() == 0 {
+		if !isPrecompile && evm.chainRules.IsEIP158 && value.IsZero() {
 			// Calling a non existing account, don't do anything, but ping the tracer
 			if debug {
 				if evm.depth == 0 {
diff --git a/core/vm/instructions.go b/core/vm/instructions.go
index ff78833ed9..023aa0af00 100644
--- a/core/vm/instructions.go
+++ b/core/vm/instructions.go
@@ -347,9 +347,7 @@ func opExtCodeSize(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext)
 }
 
 func opCodeSize(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
-	l := new(uint256.Int)
-	l.SetUint64(uint64(len(scope.Contract.Code)))
-	scope.Stack.push(l)
+	scope.Stack.push(new(uint256.Int).SetUint64(uint64(len(scope.Contract.Code))))
 	return nil, nil
 }