svn commit: r215237 - head/lib/msun/src
Alexander Best
arundel at freebsd.org
Mon Nov 15 16:28:12 UTC 2010
On Tue Nov 16 10, Bruce Evans wrote:
> On Tue, 16 Nov 2010, Bruce Evans wrote:
>
> >...
> >I checked most cases specified in n1156.pdf and found only the following
> >non-conforming behaviour in FreeBSD:
> >
> >%C99 rule -- pow(-Inf, y) returns -0 for y an odd integer <
> >0.
> >%fdlibm rule(?) * 17. -INF ** (anything) = -0 ** (-anything)
> >
> >fdlibm error: returns +0 instead of -0. I'm not sure if I matched the
> >rules correctly.
>
> False alarm. It actually returns -0 as specified.
>
> >%C99 rule -- pow(-1, +-Inf) returns 1.
> >%fdlibm rule * 9. +-1 ** +-INF is NAN
> >
> >fdlibm non-error: pow(-1, +-Inf) is NaN, not 1 as specified by C99.
> >fdlibm non-error: pow(1, +-Inf) is 1 as specified by C99, not NaN as
> >claimed in the comment.
>
> So I didn't find any non-conforming behaviour in fdlibm except for not
> conforming to the new pow(-1, +-Inf) bug (which is required for conistency
> with old bugs).
thanks for all your work. i don't think there are a lot of people able to
understand the tiny details of arithmetics, so having your expertise is
invaluable. :)
if you are interested in solving two more msun mysteries, you might want to
have a look at #PR kern/133583 and standards/143358.
cheers.
alex
>
> Bruce
--
a13x
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