From: Nathan Froyd <froydnj@codesourcery.com>
To: Aurelien Jarno <aurelien@aurel32.net>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 02/14] Add various NaN-handling macros
Date: Tue, 3 Feb 2009 12:19:09 -0800 [thread overview]
Message-ID: <20090203201908.GD15286@codesourcery.com> (raw)
In-Reply-To: <20090203194114.GA18984@volta.aurel32.net>
On Tue, Feb 03, 2009 at 08:41:14PM +0100, Aurelien Jarno wrote:
> On Thu, Jan 22, 2009 at 12:44:02PM -0800, Nathan Froyd wrote:
> > These simplify the implementation of the floating-point Altivec
> > instructions and reduce clutter.
> >
> > +#undef DO_HANDLE_NAN
> > +#undef HANDLE_NAN1
> > +#undef HANDLE_NAN2
> > +#undef HANDLE_NAN3
> > #undef VECTOR_FOR_INORDER_I
> > #undef HI_IDX
> > #undef LO_IDX
>
> This is something already handled by the softfloat code. You should use
> set_default_nan_mode(1, &env->vec_status) to get this behavior. This
> could probably done directly in the init code.
I saw the set_default_nan_mode and considered using it. It doesn't give
the same results as the above macros, though. The Altivec specs say
that if a particular input is a SNaN, then the output is the
corresponding QNaN, not the default NaN for the platform. The default
NaN is only used in specific instances. Also, QNaNs propagate through
Altivec operations; using set_default_nan_mode would mean that the
correct propagation no longer occurs.
-Nathan
next prev parent reply other threads:[~2009-02-03 20:19 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-22 20:44 [Qemu-devel] [PATCH 00/14] target-ppc: add floating-point AltiVec instructions Nathan Froyd
2009-01-22 20:44 ` [Qemu-devel] [PATCH 01/14] Add f field to ppc_avr_t Nathan Froyd
2009-02-03 19:59 ` Aurelien Jarno
2009-01-22 20:44 ` [Qemu-devel] [PATCH 02/14] Add various NaN-handling macros Nathan Froyd
2009-02-03 19:41 ` Aurelien Jarno
2009-02-03 20:19 ` Nathan Froyd [this message]
2009-02-04 9:05 ` Aurelien Jarno
2009-01-22 20:44 ` [Qemu-devel] [PATCH 03/14] Rename spe_status to vec_status Nathan Froyd
2009-02-03 19:59 ` Aurelien Jarno
2009-01-22 20:44 ` [Qemu-devel] [PATCH 04/14] Add calls to initialize VSCR on appropriate machines Nathan Froyd
2009-02-03 19:59 ` Aurelien Jarno
2009-01-22 20:44 ` [Qemu-devel] [PATCH 05/14] Make mtvscr use a helper Nathan Froyd
2009-02-03 19:59 ` Aurelien Jarno
2009-01-22 20:44 ` [Qemu-devel] [PATCH 06/14] Add v{max,min}fp instructions Nathan Froyd
2009-02-03 19:51 ` Aurelien Jarno
2009-02-04 9:06 ` Aurelien Jarno
2009-02-08 22:38 ` Nathan Froyd
2009-02-09 16:50 ` Aurelien Jarno
2009-01-22 20:44 ` [Qemu-devel] [PATCH 07/14] Add v{add,sub}fp instructions Nathan Froyd
2009-02-03 19:52 ` Aurelien Jarno
2009-02-03 20:34 ` Nathan Froyd
2009-02-08 22:39 ` Nathan Froyd
2009-02-09 16:51 ` Aurelien Jarno
2009-01-22 20:44 ` [Qemu-devel] [PATCH 08/14] Add vmaddfp and vnmsubfp instructions Nathan Froyd
2009-02-04 10:39 ` Aurelien Jarno
2009-02-08 22:39 ` Nathan Froyd
2009-02-09 16:51 ` Aurelien Jarno
2009-01-22 20:44 ` [Qemu-devel] [PATCH 09/14] Add vcmp{eq,ge,gt,b}fp{,.} instructions Nathan Froyd
2009-02-04 14:12 ` Aurelien Jarno
2009-02-08 22:40 ` [Qemu-devel] [PATCH 09/14] Add vcmp{eq, ge, gt, b}fp{, .} instructions Nathan Froyd
2009-02-09 16:51 ` Aurelien Jarno
2009-01-22 20:44 ` [Qemu-devel] [PATCH 10/14] Add vrfi{m,n,p,z} instructions Nathan Froyd
2009-02-04 13:53 ` Aurelien Jarno
2009-01-22 20:44 ` [Qemu-devel] [PATCH 11/14] Add vcf{u,s}x instructions Nathan Froyd
2009-02-04 13:54 ` Aurelien Jarno
2009-01-22 20:44 ` [Qemu-devel] [PATCH 12/14] Add vct{u,s}xs instructions Nathan Froyd
2009-02-04 14:46 ` Aurelien Jarno
2009-02-08 22:40 ` Nathan Froyd
2009-02-09 16:52 ` Aurelien Jarno
2009-01-22 20:44 ` [Qemu-devel] [PATCH 13/14] Add vrefp instruction Nathan Froyd
2009-02-04 13:56 ` Aurelien Jarno
2009-02-08 22:44 ` Nathan Froyd
2009-02-09 16:52 ` Aurelien Jarno
2009-01-22 20:44 ` [Qemu-devel] [PATCH 14/14] Add vrsqrtefp instruction Nathan Froyd
2009-02-04 13:56 ` Aurelien Jarno
2009-02-08 22:44 ` Nathan Froyd
2009-02-09 16:52 ` Aurelien Jarno
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