Re: floating point woes on i386

[Jörg Sonnenberger <joerg%bec.de@localhost>]

On 9/30/25 9:30 AM, Greg A. Woods wrote:
> At Sat, 27 Sep 2025 10:36:59 +0200, Joerg Sonnenberger <joerg%bec.de@localhost> wrote:
> Subject: Re: floating point woes on i386
> > On 9/26/25 5:50 PM, RVP wrote:
> >
> > > On Thu, 25 Sep 2025, Greg Troxel wrote:
> > >
> > > > I ran paranoia (pkgsrc/benchmarks/paranoia) on 9 and 10.  On 9:
> > > >
> > > >   The number of  FAILUREs  encountered =       3.
> > > >   The number of  SERIOUS DEFECTs  discovered = 4.
> > > >   The number of  DEFECTs  discovered =         3.
> > > >   The number of  FLAWs  discovered =           2.
> > > >
> > > > which is shocking, especially as I remember earlier NetBSD i386 versions
> > > > being ok, like 5 or 7.
> > >
> > > Force strict standards compliance with
> > > `-std=c89' or `-std=c99', or pass the
> > > `-fexcess-precision=standard' flag to the compiler.
> >
> > There is on newer i386 also the option of
> > using -mfpmath=sse. That's strictly
> > speaking the only way to get IEEE754
> > semantics on i386.
>
> On NetBSD/i386 10.0 with the system's GCC-10.5 the -mfpmath=sse option
> doesn't actually do anything:

Well, of course. You also need to use a CPU that supports SSE2 and/or 
enable the feature with -msse2.

Joerg