mirror of
https://github.com/ethereum/go-ethereum.git
synced 2026-07-27 07:06:42 +00:00
4c0e2f32f9
This changes the internals of the EVM-JIT by dropping support for blocks (and therefor also transactions) that can exceed a 64^2-1 gas-limit. This means that the EVM-JIT can drop support for abritrary precision (*big.Int) and move to 64bit based gas calculations. For obvious reasons integer overflows have added to make sure that gas calculations such as gas for memory doesn't overflow 64bit. If the overflow check fails it throws an out-of-gas error and will halt the execution of the code.
160 lines
3.4 KiB
Go
160 lines
3.4 KiB
Go
// Copyright 2014 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package common
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import (
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"math"
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"math/big"
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)
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// Common big integers often used
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var (
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Big1 = big.NewInt(1)
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Big2 = big.NewInt(2)
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Big3 = big.NewInt(3)
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Big0 = big.NewInt(0)
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BigTrue = Big1
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BigFalse = Big0
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Big32 = big.NewInt(32)
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Big36 = big.NewInt(36)
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Big97 = big.NewInt(97)
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Big98 = big.NewInt(98)
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Big256 = big.NewInt(0xff)
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Big257 = big.NewInt(257)
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MaxBig = String2Big("0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff")
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Max64Bit = new(big.Int).SetUint64(math.MaxUint64)
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)
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// Big pow
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//
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// Returns the power of two big integers
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func BigPow(a, b int) *big.Int {
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c := new(big.Int)
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c.Exp(big.NewInt(int64(a)), big.NewInt(int64(b)), big.NewInt(0))
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return c
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}
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// Big
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//
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// Shortcut for new(big.Int).SetString(..., 0)
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func Big(num string) *big.Int {
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n := new(big.Int)
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n.SetString(num, 0)
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return n
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}
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// Bytes2Big
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//
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func BytesToBig(data []byte) *big.Int {
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n := new(big.Int)
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n.SetBytes(data)
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return n
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}
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func Bytes2Big(data []byte) *big.Int { return BytesToBig(data) }
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func BigD(data []byte) *big.Int { return BytesToBig(data) }
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func String2Big(num string) *big.Int {
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n := new(big.Int)
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n.SetString(num, 0)
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return n
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}
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func BitTest(num *big.Int, i int) bool {
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return num.Bit(i) > 0
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}
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// To256
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//
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// "cast" the big int to a 256 big int (i.e., limit to)
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var tt256 = new(big.Int).Lsh(big.NewInt(1), 256)
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var tt256m1 = new(big.Int).Sub(new(big.Int).Lsh(big.NewInt(1), 256), big.NewInt(1))
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var tt255 = new(big.Int).Lsh(big.NewInt(1), 255)
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func U256(x *big.Int) *big.Int {
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//if x.Cmp(Big0) < 0 {
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// return new(big.Int).Add(tt256, x)
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// }
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x.And(x, tt256m1)
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return x
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}
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func S256(x *big.Int) *big.Int {
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if x.Cmp(tt255) < 0 {
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return x
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} else {
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// We don't want to modify x, ever
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return new(big.Int).Sub(x, tt256)
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}
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}
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func FirstBitSet(v *big.Int) int {
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for i := 0; i < v.BitLen(); i++ {
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if v.Bit(i) > 0 {
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return i
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}
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}
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return v.BitLen()
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}
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// Big to bytes
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//
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// Returns the bytes of a big integer with the size specified by **base**
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// Attempts to pad the byte array with zeros.
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func BigToBytes(num *big.Int, base int) []byte {
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ret := make([]byte, base/8)
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if len(num.Bytes()) > base/8 {
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return num.Bytes()
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}
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return append(ret[:len(ret)-len(num.Bytes())], num.Bytes()...)
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}
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// Big copy
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//
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// Creates a copy of the given big integer
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func BigCopy(src *big.Int) *big.Int {
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return new(big.Int).Set(src)
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}
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// Big max
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//
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// Returns the maximum size big integer
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func BigMax(x, y *big.Int) *big.Int {
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if x.Cmp(y) < 0 {
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return y
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}
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return x
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}
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// Big min
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//
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// Returns the minimum size big integer
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func BigMin(x, y *big.Int) *big.Int {
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if x.Cmp(y) > 0 {
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return y
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}
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return x
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}
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