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Re: netbsd build update
From: |
Jason Stover |
Subject: |
Re: netbsd build update |
Date: |
Thu, 18 May 2006 13:03:25 -0400 |
User-agent: |
Mutt/1.5.10i |
On Wed, May 17, 2006 at 08:08:42PM -0700, Ben Pfaff wrote:
> Jason Stover <address@hidden> writes:
>
> > Short answer: The alpha chip does not comply entirely with ieee 754.
> > The -mieee option to gcc fixes the problem. Maybe this option should be
> > added conditionally in Makefile.am (or wherever such things go).
>
> The problem is a floating point exception (FPE), right? (Before,
> I thought it was a segmentation fault, but I guess I
> misunderstood.) I'd expect that increased IEEE compliance would
> only prevent an FPE if it prevented, say, underflow by instead
> resulting in a denormal. If that's the case, then an underflow
> from a denormal to zero would still, presumably, cause an FPE and
> we'd only be papering over the problem, not curing.
>
> I do think that -mieee is a good idea, but I think we should look
> for a secondary problem too. Here is one idea: PSPP tries to
> turn off FPEs entirely, in fpu_init() in main.c:
>
> static void
> fpu_init (void)
> {
> #if HAVE_FEHOLDEXCEPT
> fenv_t foo;
> feholdexcept (&foo);
> #elif HAVE___SETFPUCW && defined(_FPU_IEEE)
> __setfpucw (_FPU_IEEE);
> #endif
> }
>
> Does NetBSD support either of the approaches we try there? That
> is, is HAVE_FEHOLDEXCEPT or both HAVE___SETFPUCW and _FPU_IEEE
> defined when that function is compiled? If not, then we should
> find out how we turn off FPEs on NetBSD and add that to the
> possibilities. (We should possibly warn about this at configure
> time, too.)
None of these seem to be defined on NetBSD. I couldn't see any of them
in /usr/include, and adding an assert(0) in the #if and #elif
statements above didn't cause a failure.
-Jason
- Re: netbsd build update, (continued)
- Re: netbsd build update, Jason Stover, 2006/05/16
- Re: netbsd build update, Ben Pfaff, 2006/05/16
- Re: netbsd build update, John Darrington, 2006/05/17
- Re: netbsd build update, Jason Stover, 2006/05/17
- Re: netbsd build update, Ben Pfaff, 2006/05/17
- Re: netbsd build update, John Darrington, 2006/05/17
- Re: netbsd build update, Ben Pfaff, 2006/05/17
- Re: netbsd build update, Jason Stover, 2006/05/17
- Re: netbsd build update, Ben Pfaff, 2006/05/17
- Re: netbsd build update, Jason Stover, 2006/05/18
- Re: netbsd build update,
Jason Stover <=
- Re: netbsd build update, Ben Pfaff, 2006/05/18
- Re: netbsd build update, Jason Stover, 2006/05/18
- Re: netbsd build update, Ben Pfaff, 2006/05/18
- Re: netbsd build update, John Darrington, 2006/05/18
- Re: netbsd build update, Ben Pfaff, 2006/05/18
- Re: netbsd build update, John Darrington, 2006/05/19
- Re: netbsd build update, Ben Pfaff, 2006/05/19
- Re: netbsd build update, Ben Pfaff, 2006/05/19
- Re: netbsd build update, John Darrington, 2006/05/19
- Re: netbsd build update, Ben Pfaff, 2006/05/19