Re: FLOATING-POINT CONSISTENCY, -FFLOAT-STORE, AND X86

[Toon Moene <toon at moene dot indiv dot nluug dot nl>]

N8TM@aol.com wrote:

> In a message dated 12/19/98 6:46:15 AM Pacific Standard Time,
> emil@skatter.usask.ca writes:

> <<  I very much
>  appreciate your proposal AND I endorse it completely. I am more than willing
> to
>  pay a performance penalty in order to get numerically accurate results with
> less
>  programming on my part.  >>
> I would like to join in thanking Craig for raising this issue and offering to
> work on it.    My primary objection to it was that the performance penalty
> would be too large if the problem of mis-aligned spills were not solved.  With
> that qualification, I endorse it also.

I tend to turn this remark around:  What we need in the g77 manual
(despite the fact that it is not exclusively relevant to FORTRAN) is a
section on the uses and pitfalls of floating point arithmetic.

I'll set out to write this (this won't be easy, as I have to evade the
obvious references for copyright reasons).

In the mean time, it would be useful for the compiler to warn about
testing floating point variables for (in)equality.

HTH,

-- 
Toon Moene (toon@moene.indiv.nluug.nl)
Saturnushof 14, 3738 XG  Maartensdijk, The Netherlands
Phone: +31 346 214290; Fax: +31 346 214286
g77 Support: fortran@gnu.org; egcs: egcs-bugs@cygnus.com