Bug in function powu(x,y)

[themastermindnktp]

In contract PRBMathSD59x18, on line 624, you have already modified variable y but later on line 639, you check whether y is odd or even. At that point, y is always 0, so the result of the function powu(x, y) is always positive even if x is negative and y is odd.

[PaulRBerg]

This is worth of becoming an issue. I locked this discussion and created an issue: where we can continue the conversation: #55.