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authorDeterminant <[email protected]>2020-07-30 14:18:44 -0400
committerDeterminant <[email protected]>2020-07-30 14:18:44 -0400
commit0444e66f640999c15496066637841efcc0433934 (patch)
treec19aec2dced2e9129c880c19c52ca0f87b3d62f6 /core/vm/gas.go
parentcffa0954bbdb43821d1b71d00f99fb705cecd25b (diff)
parent1f49826de2bb8bb4f5f99f69fd2beb039b1172d9 (diff)
Merge branch 'multi-coin'
Diffstat (limited to 'core/vm/gas.go')
-rw-r--r--core/vm/gas.go53
1 files changed, 53 insertions, 0 deletions
diff --git a/core/vm/gas.go b/core/vm/gas.go
new file mode 100644
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--- /dev/null
+++ b/core/vm/gas.go
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+// 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"
+)
+
+// 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.
+// As part of EIP 150 (TangerineWhistle), the returned gas is gas - base * 63 / 64.
+func callGas(isEip150 bool, availableGas, base uint64, callCost *big.Int) (uint64, error) {
+ if isEip150 {
+ 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.IsUint64() || gas < callCost.Uint64() {
+ return gas, nil
+ }
+ }
+ if !callCost.IsUint64() {
+ return 0, errGasUintOverflow
+ }
+
+ return callCost.Uint64(), nil
+}