fma without exception or rounding mode support

[Bruno Haible]

Joseph S. Myers wrote:
> * Functions in libm that only work with exception / rounding mode support.  
> The only case I know of is fma.  Bruno, in bug 13304 you expressed a 
> willingness to adapt the gnulib implementation of the fma functions to be 
> suitable for use in glibc as the math/ implementation that can be used for 
> systems without hardware exception / rounding mode support, and in 
> <http://sourceware.org/bugzilla/show_bug.cgi?id=13304#c34> I indicated I 
> thought that was the way to go - any news there?

There were two misunderstandings here:

  - I thought your comment
    <http://sourceware.org/bugzilla/show_bug.cgi?id=13304#c34>
    was advice directed to Jakub and/or Ulrich, or an action plan for
    yourself.
    If it was an action item for me, then do you want me to provide
    this replacement for math/s_fma{,f,l}.c now, for glibc 2.16 [1]? Or
    is it less urgent?

  - The proposed portable fma implementation indeed does not require
    exception nor rounding mode support. But we did not talk about this
    in the scope of bug 13304. In fact, it's the first time I hear that
    glibc would want to support such systems without providing a complete
    <fenv.h>.

Bruno

[1] http://sourceware.org/ml/libc-alpha/2012-05/msg00608.html