[Python-Dev] Python on non IEEE-754 platforms: plea for information.

[Jeffrey Yasskin]

On Feb 1, 2008 6:31 PM, Neal Norwitz <nnorwitz at gmail.com> wrote:
> On Feb 1, 2008 2:52 PM, Mark Dickinson <dickinsm at gmail.com> wrote:
> >  The IBM format is particularly troublesome because
> > it's base 16 instead of base 2 (so e.g. multiplying a float by 2 can lose
> > bits), but it appears that recent IBM machines do both IBM format and IEEE
> > format floating-point.  I assume that the S-390 buildbots are using the IEEE
> > side---is this true?
>
> I don't know and suspect the only way to figure it out would be to
> write a test that would expose which is being used.  It's using gcc,
> so we probably get whatever the compiler defaults to.  Sometimes we
> have to specify flags for certain platforms.  For example -mieee on
> the Alpha.
>
> It's fine to check in something so that you can get an answer on a buildbot.

Actually, an even better way to do this would be to craft a test case
that exposes the assumptions you've found about the floating format.
Then it'll be a valuable regression test even after someone fixes the
bug.

-- 
Namasté,
Jeffrey Yasskin