diff options
Diffstat (limited to 'core')
| -rw-r--r-- | core/vm/instructions.go | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/core/vm/instructions.go b/core/vm/instructions.go index e94a2777b..b7c3ca532 100644 --- a/core/vm/instructions.go +++ b/core/vm/instructions.go @@ -124,10 +124,22 @@ func opSmod(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory func opExp(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) { base, exponent := stack.pop(), stack.pop() - stack.push(math.Exp(base, exponent)) - - interpreter.intPool.put(base, exponent) - + // some shortcuts + cmpToOne := exponent.Cmp(big1) + if cmpToOne < 0 { // Exponent is zero + // x ^ 0 == 1 + stack.push(base.SetUint64(1)) + } else if base.Sign() == 0 { + // 0 ^ y, if y != 0, == 0 + stack.push(base.SetUint64(0)) + } else if cmpToOne == 0 { // Exponent is one + // x ^ 1 == x + stack.push(base) + } else { + stack.push(math.Exp(base, exponent)) + interpreter.intPool.put(base) + } + interpreter.intPool.put(exponent) return nil, nil } |