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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

23
core/vm/instructions.go
View File

@ -58,7 +58,7 @@ func opMul(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stac
func opDiv(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
x, y := stack.pop(), stack.pop()
if y.Cmp(common.Big0) != 0 {
if y.Sign() != 0 {
stack.push(math.U256(x.Div(x, y)))
} else {
stack.push(new(big.Int))
@ -71,12 +71,12 @@ func opDiv(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stac
func opSdiv(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
x, y := math.S256(stack.pop()), math.S256(stack.pop())
if y.Cmp(common.Big0) == 0 {
if y.Sign() == 0 {
stack.push(new(big.Int))
return nil, nil
} else {
n := new(big.Int)
if evm.interpreter.intPool.get().Mul(x, y).Cmp(common.Big0) < 0 {
if evm.interpreter.intPool.get().Mul(x, y).Sign() < 0 {
n.SetInt64(-1)
} else {
n.SetInt64(1)
@ -93,7 +93,7 @@ func opSdiv(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Sta
func opMod(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
x, y := stack.pop(), stack.pop()
if y.Cmp(common.Big0) == 0 {
if y.Sign() == 0 {
stack.push(new(big.Int))
} else {
stack.push(math.U256(x.Mod(x, y)))
@ -105,11 +105,11 @@ func opMod(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stac
func opSmod(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
x, y := math.S256(stack.pop()), math.S256(stack.pop())
if y.Cmp(common.Big0) == 0 {
if y.Sign() == 0 {
stack.push(new(big.Int))
} else {
n := new(big.Int)
if x.Cmp(common.Big0) < 0 {
if x.Sign() < 0 {
n.SetInt64(-1)
} else {
n.SetInt64(1)
@ -221,7 +221,7 @@ func opEq(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack
func opIszero(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
x := stack.pop()
if x.Cmp(common.Big0) > 0 {
if x.Sign() > 0 {
stack.push(new(big.Int))
} else {
stack.push(evm.interpreter.intPool.get().SetUint64(1))
@ -252,10 +252,11 @@ func opXor(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stac
evm.interpreter.intPool.put(y)
return nil, nil
}
func opByte(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
th, val := stack.pop(), stack.pop()
if th.Cmp(big.NewInt(32)) < 0 {
byte := evm.interpreter.intPool.get().SetInt64(int64(common.LeftPadBytes(val.Bytes(), 32)[th.Int64()]))
byte := evm.interpreter.intPool.get().SetInt64(int64(math.PaddedBigBytes(val, 32)[th.Int64()]))
stack.push(byte)
} else {
stack.push(new(big.Int))
@ -505,7 +506,7 @@ func opJump(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Sta
}
func opJumpi(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
pos, cond := stack.pop(), stack.pop()
if cond.BitLen() > 0 {
if cond.Sign() != 0 {
if !contract.jumpdests.has(contract.CodeHash, contract.Code, pos) {
nop := contract.GetOp(pos.Uint64())
return nil, fmt.Errorf("invalid jump destination (%v) %v", nop, pos)
@ -583,7 +584,7 @@ func opCall(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Sta
// Get the arguments from the memory
args := memory.Get(inOffset.Int64(), inSize.Int64())
if value.BitLen() > 0 {
if value.Sign() != 0 {
gas += params.CallStipend
}
@ -616,7 +617,7 @@ func opCallCode(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack
// Get the arguments from the memory
args := memory.Get(inOffset.Int64(), inSize.Int64())
if value.BitLen() > 0 {
if value.Sign() != 0 {
gas += params.CallStipend
}