Re: yet another Java oddity

[Daniel J Sebald]

On 02/07/2013 09:32 AM, John W. Eaton wrote:
> On 02/07/2013 10:25 AM, Mike Miller wrote:

[snip]

> > Run till exit from #0 __pow (x=10, y=-5) at w_pow.c:35
> > xpow (a=10, b=-5) at ../../default/libinterp/interp-core/xpow.cc:95
> > 95 return retval;
> > Value returned is $1 = 1.0000000000000001e-05
> > (gdb) cont
> > Continuing.

[snip]

> > Run till exit from #0 __pow (x=10, y=-5) at w_pow.c:35
> > xpow (a=10, b=-5) at ../../default/libinterp/interp-core/xpow.cc:95
> > 95 return retval;
> > Value returned is $2 = 1.0000000000000006e-05
> > (gdb) cont
> > Continuing.
> > ans = 1.0000e-05
> >
> > Looks to me like the same call stack with different return values.
>
> That's odd. Does the JVM set some FPU flags that are different from the
> default that could affect the values that std::pow computes?

I was just about to email to propose that could be happening.  Perhaps 
there is a bug in Java that isn't fully restoring the state of the CPU 
registers when it returns.  Could be a machine specific problem.

Dan