Bug#327351: Fixed in local cvs.parisc-linux.org, sorry for not submitting upstream.

[Carlos O'Donell <carlos@systemhalted.org>]

On Thu, Oct 13, 2005 at 11:10:18PM -0400, Daniel Jacobowitz wrote:
> On Wed, Sep 21, 2005 at 12:46:48PM -0400, Carlos O'Donell wrote:
> > int
> > fesetround (int round)
> > {
> >   struct { unsigned int sw[2]; } s;
> > 
> >   /* Get the current status word. */
> >   __asm__ ("fstd %%fr0,0(%1)" : "=m" (s) : "r" (&s) : "%r0");
> >   s.sw[0] &= ~FE_DOWNWARD;
> >   s.sw[0] |= round & FE_DOWNWARD;
> >   __asm__ ("fldd 0(%0),%%fr0" : : "r" (&s), "m" (s) : "%r0");
> > 
> >   return 0;
> > }
> > ---
> > 
> > Comments:
> > - Please do not return 1 if the rounding mode is invalid.
> >   Try as hard as possible to set something reasonable.
> > - Use a struct where possible for two integers since GCC
> >   will generally have an easier time following the memory.
> > - These are double word stores, so you need sw[2].
> 
> Er... how can comment #1 possibly be correct?  The documentation's
> clear: fesetround should return 1 if it could not set the requested
> rounding mode.

info glibc?

AFAIU the return was undefined if the input is not one of the rounding
macros. I meant only to make the function more robust, but in retrospect
you are right, it should be more conformant.

To be clear the section 7.6.3.2 fesetround of the ISO C spec says that
zero should only be returned when the round value matches one of the
rounding macros. 

And this function does not do that. I should not go around recommending
people break spec :}

c.