Shared toom evaluation functions

[Paul Zimmermann]

> nisse at lysator.liu.se (Niels Möller) writes:
> 
>   Torbjorn Granlund <tg at gmplib.org> writes:
>   
>   > I think we might want to make our lives in toom more difficult:
>   >
>   > We should add, to gmp-mparam.h, cycle counts for available mpn functions
>   > as first degree polynomials.  Measurements for that can easily be added
>   > to tuneup.c.
>   
>   I was about to suggest something similar, but a little simpler, with
>   only a cycles/limb value for each of the O(n) functions. Do you think
>   the constant overhead is important here?
>   
> Perhaps not here, but it will be useful elsewhere.  It is not hard to
> measure one paramater when we measure the other.

I personally like this idea of measuring the cycles as a+bn instead of
just bn. We might extend it to a+bn+cn^2 for say mpn_mul_n_basecase.

Paul