svn commit: r215237 - head/lib/msun/src

[Alexander Best]

On Sat Nov 13 10, Steve Kargl wrote:
> On Sat, Nov 13, 2010 at 12:56:48PM +0000, Alexander Best wrote:
> > On Sat Nov 13 10, Ulrich Spoerlein wrote:
> > > Author: uqs
> > > Date: Sat Nov 13 10:54:10 2010
> > > New Revision: 215237
> > > URL: http://svn.freebsd.org/changeset/base/215237
> > > 
> > > Log:
> > >   Fix bug in jn(3) and jnf(3) that led to -inf results
> > 
> > thank you very much for fixing this long outstanding issue.
> > you might want to have a look at [1], where two more issues have been reported.
> > 
> > cheers.
> > alex
> > 
> > [1] http://mailman.oakapple.net/pipermail/numeric-interest/2010-September/thread.html
> > 
> 
> Ulrich, thanks.  Of the two remaining issues, I can verify
> one is indeed an issue.

also it seems one of the regression tests in tools/regression/lib/msun fails
(assert tripped): test-lrint.

cheers.
alex

> 
> laptop:kargl[204] cat mn.c
> #include <stdio.h>
> #include <math.h>
> 
> static const double z = 0.;
> 
> int
> main(void)
> {
>    double x, y;
>    x = -1. / z;
>    y = exp( 0.5 * log(x));
>    printf("pow(%f,  0.5) = %le, %le\n", x, pow(x,  0.5), y);
>    y = exp(-0.5 * log(x));
>    printf("pow(%f, -0.5) = %le, %le\n", x, pow(x, -0.5), y);
>    return 0;
> }
> 
> laptop:kargl[205] cc -o z mn.c -fno-builtin -lm && ./z
> pow(-inf,  0.5) = inf, nan
> pow(-inf, -0.5) = 0.000000e+00, nan
> 
> -- 
> Steve

-- 
a13x