RFC Migrating PowerPC to IEEE 128-bit Floating Point

[Joseph Myers]

On Wed, 14 Oct 2015, Andreas Schwab wrote:

> Joseph Myers <joseph@codesourcery.com> writes:
> 
> > but I strongly suspect that some of the code in
> > sysdeps/ieee754/ldbl-96 does not handle the m68k variant fully
> > correctly.)
> 
> m68k uses only a few of them, and I don't think any of them is testing
> for subnormal values.

I'm pretty sure that fmal is not correct for m68k.  There are lots of 
conditionals to avoid internal underflow when the final result does not 
underflow, while ensuring correctly rounded results with underflow 
exception when such an exception is correct.  All of those conditionals 
are analogous to those for flt-32 / dbl-64 / ldbl-128 and make no 
allowance for the m68k format - and testcases were generally written to 
cover problem cases for those formats and for the Intel version of ldbl-96 
and so may not expose problems for m68k either.  (Some conditionals may be 
safe for m68k for one reason or another, but probably not all.)

-- 
Joseph S. Myers
joseph@codesourcery.com