Multiplying two UINT256 to a UINT512

[Th0rgal]

Hello,

I need to compute a multiplication of two integers a, b modulo a big prime P. Those integers and the prime fit in a UINT256, but to compute the result of a*b mod P I need to compute a*b which doesn't fit in a UINT256. Would it be possible to add another method perfect_mul (or another name) which gives the UINT512 result in an efficient way or should I use UINT512 everywhere?

Thanks for your work, Thomas

[ordian]

Hey, sorry for the delay in reply. Take a look at

https://github.com/paritytech/parity-common/blob/854e68bb5af1bf285445228c47d1a1090e1f1bf3/primitive-types/src/lib.rs#L153-L160

Hope that helps.