T3/T3 mul_2 and addmul_2

[David Miller]

From: Torbjorn Granlund <tg at gmplib.org>
Date: Fri, 08 Mar 2013 21:23:55 +0100

> If you want to play with this, please start with the checked in code
> (you'll need to fresh configure.ac to allow the aormul_2 'multifunc'
> name).  The first thing to try is its speed compared to the code you
> timed above.

I'll look into this when I get back from Copenhagen, in about
a week.