Hi there,

Just wondering if Povray supports 3DNow (plain vanilla K6-2 and/or extended
Athlon), and if not if it plans to support it in the future.

Thanks
Michael

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"Michael Brown" <emb### [at] i4freeDELETETHISconz> wrote in message
news:3a715049@news.povray.org...
> Hi there,
>
> Just wondering if Povray supports 3DNow (plain vanilla K6-2 and/or
extended
> Athlon), and if not if it plans to support it in the future.
>

Is 3DNow relevant to POV? I may have misunderstood, but I thought it just
increased the speed of 3d graphics and multi-media, and would therefore have
no effect on rendering. That said, 3DNow does, I believe, speed up floating
point calculations.

Question: If 3DNow speeds up float calcs, why is it only of benefit to
graphics and not all apps. using floating point calcs.?

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Tom Melly wrote:
>  
> Question: If 3DNow speeds up float calcs, why is it only of benefit to
> graphics and not all apps. using floating point calcs.?


As I understood it, 3DNow supports single precision floating point only.
But POV (and ray-tracing in general) needs double precision to get good
pictures (there is a thread in p.unofficial.patches about why this is
so). Therefore 3DNow is useless for POV.

- Micha

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Micha Riser wrote:
> 
> As I understood it, 3DNow supports single precision floating point only.
> But POV (and ray-tracing in general) needs double precision to get good
> pictures (there is a thread in p.unofficial.patches about why this is
> so). Therefore 3DNow is useless for POV.
> 
> - Micha

Specifically the threads:

3D!Now & ISSE
double/single precision

BTW, wouldn't that be a good addition to the VFAQ?

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/

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Tom Melly wrote:
>
> Question: If 3DNow speeds up float calcs, why is it only of benefit to
> graphics and not all apps. using floating point calcs.?

WinAmp uses 3DNow to decode mp3s.

______________________________________________________________________
Kari Kivisalo                                  http://www.kivisalo.net

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"Kari Kivisalo" <kar### [at] kivisalonet> wrote in message
news:3A717C79.10257149@kivisalo.net...
> Tom Melly wrote:
> >
> > Question: If 3DNow speeds up float calcs, why is it only of benefit to
> > graphics and not all apps. using floating point calcs.?
>
> WinAmp uses 3DNow to decode mp3s.
>

Yes - I gathered that it applied to multi-media (hate that term) - this is
partly what confused me. MM as a generic set of apps is hardly likely to
benefit from something unless that something can also benefit non-MM apps.
The answer would appear to be the 3dnow only works on single-point.

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Just have to push to get AMD to beef up 3DNow with double precision, I
guess. Could call it Super Extended 3DNow!  :)
And yes, it would be a good addition to the FAQ.

"Christoph Hormann" <chr### [at] gmxde> wrote in message
news:3A717642.3C96091C@gmx.de...
>
>
> Micha Riser wrote:
> >
> > As I understood it, 3DNow supports single precision floating point only.
> > But POV (and ray-tracing in general) needs double precision to get good
> > pictures (there is a thread in p.unofficial.patches about why this is
> > so). Therefore 3DNow is useless for POV.
> >
> > - Micha
>
> Specifically the threads:
>
> 3D!Now & ISSE
> double/single precision
>
> BTW, wouldn't that be a good addition to the VFAQ?
>
> Christoph
>
> --
> Christoph Hormann <chr### [at] gmxde>
> IsoWood include, radiosity tutorial, TransSkin and other
> things on: http://www.schunter.etc.tu-bs.de/~chris/

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Tom Melly wrote:

> "Kari Kivisalo" <kar### [at] kivisalonet> wrote in message
> news:3A717C79.10257149@kivisalo.net...
> > Tom Melly wrote:
> > >
> > > Question: If 3DNow speeds up float calcs, why is it only of benefit to
> > > graphics and not all apps. using floating point calcs.?
> >
> > WinAmp uses 3DNow to decode mp3s.
> >
>
> Yes - I gathered that it applied to multi-media (hate that term) - this is
> partly what confused me. MM as a generic set of apps is hardly likely to
> benefit from something unless that something can also benefit non-MM apps.
> The answer would appear to be the 3dnow only works on single-point.

My understanding of 3dnow, and intel's counterpart Katimi new instructions, is
that it merely allows you to do the same instruction on several pieces of data
simultaneously.  Basically it saves clock cycles by not having to repeat the
same instruction.  Example multiplying normally you would input something like
this into the processor: data, data, multiply, data, data, multiply, data,
data, multiply... But with (single instruction multiple data) it would use a
single command to to input all the multiply's.  Well this is my understanding
of it.  I have never read the actual list of commands an intel processor
recognizes.

Dan Johnson

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http://www.students.tut.fi/~warp/povVFAQ/miscVFAQ.html#3dnow

-- 
char*i="b[7FK@`3NB6>B:b3O6>:B:b3O6><`3:;8:6f733:>::b?7B>:>^B>C73;S1";
main(_,c,m){for(m=32;c=*i++-49;c&m?puts(""):m)for(_=(
c/4)&7;putchar(m),_--?m:(_=(1<<(c&3))-1,(m^=3)&3););}    /*- Warp -*/

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On 2001-01-26 10:31, Michael Brown <emb### [at] i4freeDELETETHISconz> wrote:
>Just wondering if Povray supports 3DNow (plain vanilla K6-2 and/or extended
>Athlon), and if not if it plans to support it in the future.

Look in povray.unofficial.patches. Daniel Jungmann has converted the
color handling (which is single precision) to use 3D!Now and reports a
speedup of at least 50%.

	hp


-- 
   _  | Peter J. Holzer    | All Linux applications run on Solaris,
|_|_) | Sysadmin WSR       | which is our implementation of Linux.
| |   | hjp### [at] wsracat      | 
__/   | http://www.hjp.at/ |	-- Scott McNealy, Dec. 2000

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