56 lines
1.8 KiB
Go
56 lines
1.8 KiB
Go
// Copyright 2015 The go-ethereum Authors
|
|
// This file is part of the go-ethereum library.
|
|
//
|
|
// The go-ethereum library is free software: you can redistribute it and/or modify
|
|
// it under the terms of the GNU Lesser General Public License as published by
|
|
// the Free Software Foundation, either version 3 of the License, or
|
|
// (at your option) any later version.
|
|
//
|
|
// The go-ethereum library is distributed in the hope that it will be useful,
|
|
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
// GNU Lesser General Public License for more details.
|
|
//
|
|
// You should have received a copy of the GNU Lesser General Public License
|
|
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
package vm
|
|
|
|
import (
|
|
"math/big"
|
|
|
|
"github.com/ethereum/go-ethereum/params"
|
|
)
|
|
|
|
// Gas costs
|
|
const (
|
|
GasQuickStep uint64 = 2
|
|
GasFastestStep uint64 = 3
|
|
GasFastStep uint64 = 5
|
|
GasMidStep uint64 = 8
|
|
GasSlowStep uint64 = 10
|
|
GasExtStep uint64 = 20
|
|
)
|
|
|
|
// calcGas returns the actual gas cost of the call.
|
|
//
|
|
// The cost of gas was changed during the homestead price change HF. To allow for EIP150
|
|
// to be implemented. The returned gas is gas - base * 63 / 64.
|
|
func callGas(gasTable params.GasTable, availableGas, base uint64, callCost *big.Int) (uint64, error) {
|
|
if gasTable.CreateBySuicide > 0 {
|
|
availableGas = availableGas - base
|
|
gas := availableGas - availableGas/64
|
|
// If the bit length exceeds 64 bit we know that the newly calculated "gas" for EIP150
|
|
// is smaller than the requested amount. Therefor we return the new gas instead
|
|
// of returning an error.
|
|
if callCost.BitLen() > 64 || gas < callCost.Uint64() {
|
|
return gas, nil
|
|
}
|
|
}
|
|
if callCost.BitLen() > 64 {
|
|
return 0, errGasUintOverflow
|
|
}
|
|
|
|
return callCost.Uint64(), nil
|
|
}
|