public override void Execute()
{
// Obtain our value and exponent
BigInteger value = Stack.Pop();
BigInteger exponent = Stack.Pop();
// Calculate how much gas to deduct: the cost per exponent byte differs per Ethereum release
byte[] exponentBytes = BigIntegerConverter.GetBytesWithoutLeadingZeros(exponent);
BigInteger extraGasCost = exponentBytes.Length;
if (Version < EthereumRelease.SpuriousDragon)
{
// Pre-Spurious Dragon
extraGasCost *= GasDefinitions.GAS_EXP_BYTE;
}
else
{
// Spurious Dragon+
extraGasCost *= GasDefinitions.GAS_EXP_BYTE_SPURIOUS_DRAGON;
}
// Deduct our gas
GasState.Deduct(extraGasCost);
// Perform an exponent operation on the two unsigned words off of the top of the stack.
BigInteger result = BigInteger.ModPow(value, exponent, EVMDefinitions.UINT256_MAX_VALUE + 1);
// Push the result onto the stack.
Stack.Push(result);
}
// Type handling
public static RLPByteArray FromInteger(BigInteger bigInteger, int byteCount = 32, bool removeLeadingZeros = false)
{
if (!removeLeadingZeros)
{
return(new RLPByteArray(BigIntegerConverter.GetBytes(bigInteger, byteCount)));
}
else
{
return(new RLPByteArray(BigIntegerConverter.GetBytesWithoutLeadingZeros(bigInteger, byteCount)));
}
}