From c12f4df910e2da1cc5dd28c5c4bbe2d8721e1057 Mon Sep 17 00:00:00 2001 From: Jeffrey Wilcke Date: Wed, 4 Jan 2017 20:17:24 +0100 Subject: params: core, core/vm, miner: 64bit gas instructions Reworked the EVM gas instructions to use 64bit integers rather than arbitrary size big ints. All gas operations, be it additions, multiplications or divisions, are checked and guarded against 64 bit integer overflows. In additon, most of the protocol paramaters in the params package have been converted to uint64 and are now constants rather than variables. * common/math: added overflow check ops * core: vmenv, env renamed to evm * eth, internal/ethapi, les: unmetered eth_call and cancel methods * core/vm: implemented big.Int pool for evm instructions * core/vm: unexported intPool methods & verification methods * core/vm: added memoryGasCost overflow check and test --- common/math/integer.go | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) create mode 100644 common/math/integer.go (limited to 'common/math/integer.go') diff --git a/common/math/integer.go b/common/math/integer.go new file mode 100644 index 000000000..8162b1985 --- /dev/null +++ b/common/math/integer.go @@ -0,0 +1,25 @@ +package math + +import gmath "math" + +/* + * NOTE: The following methods need to be optimised using either bit checking or asm + */ + +// SafeSub returns subtraction result and whether overflow occurred. +func SafeSub(x, y uint64) (uint64, bool) { + return x - y, x < y +} + +// SafeAdd returns the result and whether overflow occurred. +func SafeAdd(x, y uint64) (uint64, bool) { + return x + y, y > gmath.MaxUint64-x +} + +// SafeMul returns multiplication result and whether overflow occurred. +func SafeMul(x, y uint64) (uint64, bool) { + if x == 0 { + return 0, false + } + return x * y, x != 0 && y != 0 && y > gmath.MaxUint64/x +} -- cgit v1.2.3