Re: IEEE NaN and Trichotomy

[alms@cambridge.apple.com (Andrew LM Shalit)]

At  3:15 PM 12/22/92 -0400, Robert A. Cassels wrote:
> At 12:02 PM 12/22/92 -0500, Jim Allard wrote:
> >Robert Cassels responds:
> >
> 
> >As an FYI about my motivation for the comparison implementation options in my
> >previous note, I kept looking for a way to avoid giving the "wrong" IEEE
> >answer.  I was inclined towards this approach since I felt it was consistent
> >with the pains that have been taken to keep Dylan "safe", so I had expected an
> >error on NaN comparison.
> 
> I have no objection to signalling an exception on NaN comparisons.  (It's
> what I did with NaN comparisons for Symbolics machines.)  I haven't looked
> at what performance implications that might have on which platforms.  (And
> you're concerned about a "not" instruction.  :-)

If my memory serves me correctly, signalling an exception on NaN comparisons
wouldn't bee IEEE compatible.  You have to return #f.

  -Andrew