1 files changed, 16 insertions, 13 deletions
diff --git a/core/gaspool.go b/core/gaspool.go
index ef99908cf..c3ee5c198 100644
--- a/core/gaspool.go
+++ b/core/gaspool.go
@@ -16,31 +16,34 @@
 
 package core
 
-import "math/big"
+import (
+	"fmt"
+	"math"
+)
 
-// GasPool tracks the amount of gas available during
-// execution of the transactions in a block.
-// The zero value is a pool with zero gas available.
-type GasPool big.Int
+// GasPool tracks the amount of gas available during execution of the transactions
+// in a block. The zero value is a pool with zero gas available.
+type GasPool uint64
 
 // AddGas makes gas available for execution.
-func (gp *GasPool) AddGas(amount *big.Int) *GasPool {
-	i := (*big.Int)(gp)
-	i.Add(i, amount)
+func (gp *GasPool) AddGas(amount uint64) *GasPool {
+	if uint64(*gp) > math.MaxUint64-amount {
+		panic("gas pool pushed above uint64")
+	}
+	*(*uint64)(gp) += amount
 	return gp
 }
 
 // SubGas deducts the given amount from the pool if enough gas is
 // available and returns an error otherwise.
-func (gp *GasPool) SubGas(amount *big.Int) error {
-	i := (*big.Int)(gp)
-	if i.Cmp(amount) < 0 {
+func (gp *GasPool) SubGas(amount uint64) error {
+	if uint64(*gp) < amount {
 		return ErrGasLimitReached
 	}
-	i.Sub(i, amount)
+	*(*uint64)(gp) -= amount
 	return nil
 }
 
 func (gp *GasPool) String() string {
-	return (*big.Int)(gp).String()
+	return fmt.Sprintf("%d", *gp)
 }