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all: unify big.Int zero checks, use common/math in more places (#3716)

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* common/math: optimize PaddedBigBytes, use it more

name              old time/op    new time/op    delta
PaddedBigBytes-8    71.1ns ± 5%    46.1ns ± 1%  -35.15%  (p=0.000 n=20+19)

name              old alloc/op   new alloc/op   delta
PaddedBigBytes-8     48.0B ± 0%     32.0B ± 0%  -33.33%  (p=0.000 n=20+20)

* all: unify big.Int zero checks

Various checks were in use. This commit replaces them all with Int.Sign,
which is cheaper and less code.

eg templates:

    func before(x *big.Int) bool { return x.BitLen() == 0 }
    func after(x *big.Int) bool  { return x.Sign() == 0 }

    func before(x *big.Int) bool { return x.BitLen() > 0 }
    func after(x *big.Int) bool  { return x.Sign() != 0 }

    func before(x *big.Int) int { return x.Cmp(common.Big0) }
    func after(x *big.Int) int  { return x.Sign() }

* common/math, crypto/secp256k1: make ReadBits public in package math
This commit is contained in:
Felix Lange
2017-02-28 15:09:11 +01:00
committed by Jeffrey Wilcke
parent d4f60d362b
commit 5f7826270c
30 changed files with 104 additions and 114 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
core/vm/gas_table.go
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@ -273,7 +273,7 @@ func gasExp(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem
func gasCall(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
var (
gas = gt.Calls
transfersValue = stack.Back(2).BitLen() > 0
transfersValue = stack.Back(2).Sign() != 0
address = common.BigToAddress(stack.Back(1))
eip158 = evm.ChainConfig().IsEIP158(evm.BlockNumber)
)
@ -316,7 +316,7 @@ func gasCall(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem
func gasCallCode(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
gas := gt.Calls
if stack.Back(2).BitLen() > 0 {
if stack.Back(2).Sign() != 0 {
gas += params.CallValueTransferGas
}
memoryGas, err := memoryGasCost(mem, memorySize)
@ -362,7 +362,7 @@ func gasSuicide(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack,
if eip158 {
// if empty and transfers value
if evm.StateDB.Empty(address) && evm.StateDB.GetBalance(contract.Address()).BitLen() > 0 {
if evm.StateDB.Empty(address) && evm.StateDB.GetBalance(contract.Address()).Sign() != 0 {
gas += gt.CreateBySuicide
}
} else if !evm.StateDB.Exist(address) {