Re: Forwarded patch for modular exponentiation support (GMP powm)

[Kevin Ryde]

I wrote:
>
> Also, if m is negative

Oops, I meant the exponent k there.

> The case can be detected
> by mpz_invert, though it will be wasteful to do the same as what
> mpz_powm is about to do.

Actually, I think what you'll want is to call mpz_invert explicitly,
then mpz_powm with the inverse (when it exists) and the absolute value
of the exponent.