core/vm: implement RETURNDATA metropolis opcodes

1 files changed, 26 insertions, 0 deletions

diff --git a/core/vm/gas_table.go b/core/vm/gas_table.go
index 8a6c2741d..6cdbc5c39 100644
--- a/core/vm/gas_table.go
+++ b/core/vm/gas_table.go
@@ -91,6 +91,32 @@ func gasCalldataCopy(gt params.GasTable, evm *EVM, contract *Contract, stack *St
 	return gas, nil
 }
 
+func gasReturnDataCopy(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
+	gas, err := memoryGasCost(mem, memorySize)
+	if err != nil {
+		return 0, err
+	}
+
+	var overflow bool
+	if gas, overflow = math.SafeAdd(gas, GasFastestStep); overflow {
+		return 0, errGasUintOverflow
+	}
+
+	words, overflow := bigUint64(stack.Back(2))
+	if overflow {
+		return 0, errGasUintOverflow
+	}
+
+	if words, overflow = math.SafeMul(toWordSize(words), params.CopyGas); overflow {
+		return 0, errGasUintOverflow
+	}
+
+	if gas, overflow = math.SafeAdd(gas, words); overflow {
+		return 0, errGasUintOverflow
+	}
+	return gas, nil
+}
+
 func gasSStore(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
 	var (
 		y, x = stack.Back(1), stack.Back(0)