[PATCH] Implement fma correctly

[Ulrich Drepper]

Going back to this:

On Tue, Oct 12, 2010 at 18:02, Richard Henderson <rth@twiddle.net> wrote:
> You'd have to either
> open-code that function in order avoid doing extra work,
> or add new helper functions.

Add #ifdef code in the generic implementation, depending on some new
macro which does the switching of the round mode and the precision.
arch-specific wrappers of the file can define those symbols before
including the generic implementation.  In case there is no such macro
use the current generic code.