1 files changed, 21 insertions, 18 deletions

diff --git a/core/vm/contracts.go b/core/vm/contracts.go
index 9645d268f..593b6ca55 100644
--- a/core/vm/contracts.go
+++ b/core/vm/contracts.go
@@ -17,8 +17,6 @@
 package vm
 
 import (
-	"math/big"
-
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/logger"
@@ -30,8 +28,8 @@ import (
 // requires a deterministic gas count based on the input size of the Run method of the
 // contract.
 type PrecompiledContract interface {
-	RequiredGas(inputSize int) *big.Int // RequiredPrice calculates the contract gas use
-	Run(input []byte) []byte            // Run runs the precompiled contract
+	RequiredGas(inputSize int) uint64 // RequiredPrice calculates the contract gas use
+	Run(input []byte) []byte          // Run runs the precompiled contract
 }
 
 // Precompiled contains the default set of ethereum contracts
@@ -57,7 +55,7 @@ func RunPrecompiledContract(p PrecompiledContract, input []byte, contract *Contr
 // ECRECOVER implemented as a native contract
 type ecrecover struct{}
 
-func (c *ecrecover) RequiredGas(inputSize int) *big.Int {
+func (c *ecrecover) RequiredGas(inputSize int) uint64 {
 	return params.EcrecoverGas
 }
 
@@ -92,10 +90,12 @@ func (c *ecrecover) Run(in []byte) []byte {
 // SHA256 implemented as a native contract
 type sha256 struct{}
 
-func (c *sha256) RequiredGas(inputSize int) *big.Int {
-	n := big.NewInt(int64(inputSize+31) / 32)
-	n.Mul(n, params.Sha256WordGas)
-	return n.Add(n, params.Sha256Gas)
+// RequiredGas returns the gas required to execute the pre-compiled contract.
+//
+// This method does not require any overflow checking as the input size gas costs
+// required for anything significant is so high it's impossible to pay for.
+func (c *sha256) RequiredGas(inputSize int) uint64 {
+	return uint64(inputSize+31)/32*params.Sha256WordGas + params.Sha256Gas
 }
 func (c *sha256) Run(in []byte) []byte {
 	return crypto.Sha256(in)
@@ -104,10 +104,12 @@ func (c *sha256) Run(in []byte) []byte {
 // RIPMED160 implemented as a native contract
 type ripemd160 struct{}
 
-func (c *ripemd160) RequiredGas(inputSize int) *big.Int {
-	n := big.NewInt(int64(inputSize+31) / 32)
-	n.Mul(n, params.Ripemd160WordGas)
-	return n.Add(n, params.Ripemd160Gas)
+// RequiredGas returns the gas required to execute the pre-compiled contract.
+//
+// This method does not require any overflow checking as the input size gas costs
+// required for anything significant is so high it's impossible to pay for.
+func (c *ripemd160) RequiredGas(inputSize int) uint64 {
+	return uint64(inputSize+31)/32*params.Ripemd160WordGas + params.Ripemd160Gas
 }
 func (c *ripemd160) Run(in []byte) []byte {
 	return common.LeftPadBytes(crypto.Ripemd160(in), 32)
@@ -116,11 +118,12 @@ func (c *ripemd160) Run(in []byte) []byte {
 // data copy implemented as a native contract
 type dataCopy struct{}
 
-func (c *dataCopy) RequiredGas(inputSize int) *big.Int {
-	n := big.NewInt(int64(inputSize+31) / 32)
-	n.Mul(n, params.IdentityWordGas)
-
-	return n.Add(n, params.IdentityGas)
+// RequiredGas returns the gas required to execute the pre-compiled contract.
+//
+// This method does not require any overflow checking as the input size gas costs
+// required for anything significant is so high it's impossible to pay for.
+func (c *dataCopy) RequiredGas(inputSize int) uint64 {
+	return uint64(inputSize+31)/32*params.IdentityWordGas + params.IdentityGas
 }
 func (c *dataCopy) Run(in []byte) []byte {
 	return in