longlong.h and cpu type vectoring...

[David Miller]

From: Torbjorn Granlund <tg at gmplib.org>
Date: Tue, 09 Apr 2013 21:24:59 +0200

> David Miller <davem at davemloft.net> writes:
> 
>   That's my argument, leave the most generic code in longlong.h and if
>   something is critical.. then we have an assembler variant.
>   
> This is not how we usually do things, and there are arguments against
> that as GMP is currently organised.  Look for all usages of umul_ppmm,
> spread all over GMP.  For a fat binary, we will need to cope with its
> absence, if it is not generally available.
> 
> I'd like to work on supporting more fat binaries and also work on making
> those as close to "lean" binaries in performance.  We should not do that
> by missing out on optimisation opportunities for lean binaries.

Ok, so would you propose to do something like build the mpn/generic/
code using "mcpu=whatever" to create an instance of those objects for
each target we want to cover in the fat binary?

> It is not too hard to do these types of tricks in m4; we in fact do that
> for some x86 instructions already.

Then I would suggest we handle this sparc ELF binary tagging issue in
this way.