Organization of multiplication functions

[Torbjorn Granlund]

Kevin Ryde <user42 at zip.com.au> writes:

  Of course there's probably not much chance of anyone writing a
  realistic program which uses mul but not sqr.
  
That's not the main reason.  I'm trying to allow for better
function inlining.

  The other reorganisation was to split the toom3 out, so that by
  setting the thresholds one could get only the karatsuba code,
  if trying to save code space, esp if knowing only moderate
  sized operands are going to arise.
  
We might want to allow configure-time selection of what routines
to include, but I would prefer if that resulted in cpp macros
that conditionally exclude code.  We already have WANT_FFT, and
could add WANT_TOOM and WANT_KARATSUBA.

Dunno how much use this would get, though.  Cryptographers might
want to use it, to have less code to worry about, and if anybody
would want to put GMP in an embedded system, it would probably be
useful as well.

--
Torbjörn