forks/go-ethereum
1
0
Fork 1
mirror of https://github.com/ethereum/go-ethereum.git synced 2026-07-26 14:46:42 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

vm: optimize EXP

Browse source 
Optimize EXP performance by using simple algorithm that replaces division with
a bit mask.
This commit is contained in:
Paweł Bylica 2016-10-19 17:16:06 +02:00
parent 8048f4d4f6
commit 2ae2a78f38
No known key found for this signature in database
GPG key ID: 7A0C037434FE77EF
1 changed files with 10 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

12
core/vm/instructions.go
View file

@ -192,8 +192,16 @@ func opSmod(instr instruction, pc *uint64, env Environment, contract *Contract,
} }
func opExp(instr instruction, pc *uint64, env Environment, contract *Contract, memory *Memory, stack *Stack) { func opExp(instr instruction, pc *uint64, env Environment, contract *Contract, memory *Memory, stack *Stack) {
x, y := stack.pop(), stack.pop() base, exponent := stack.pop(), stack.pop()
stack.push(U256(x.Exp(x, y, Pow256))) result := big.NewInt(1)
for exponent.Cmp(common.Big0) != 0 {
if exponent.Bit(0) == 1 {
U256(result.Mul(result, base))
}
U256(base.Mul(base, base))
exponent.Rsh(exponent, 1)
}
stack.push(result)
} }
func opSignExtend(instr instruction, pc *uint64, env Environment, contract *Contract, memory *Memory, stack *Stack) { func opSignExtend(instr instruction, pc *uint64, env Environment, contract *Contract, memory *Memory, stack *Stack) {