Re: [Openexr-devel] Conversion between half-float and float

[Paul Schneider]

Hi, Kennant,

If you don't have a nice video card, but you do have a Mac, you might 
be able to use these Altivec-enabled conversion routines.  If you're on 
an x86 machine and you have some experience with SSE, you might be able 
to adapt these algorithms to do SIMD conversions using SSE.

From: "Derek Ledbetter" <address@hidden>
Date: August 28, 2003 4:54:05 PM PDT
To: <address@hidden>
Subject: [Openexr-devel] AltiVec functions that operate on "half"

I wrote two functions that use AltiVec (the vector processing unit on
 the PowerPC G4 and G5) to convert between "half"s and "float"s.  I 
found
 that converting a large array of "float"s to "half"s is about three
 times faster using AltiVec, and it's about 1.7 times as fast going the
 other way.  I figure that they should be useful for other functions 
too.

 <http://www.serve.com/derekl/openexr/AltiVecHalfConversion.html>
 --
 Derek Ledbetter
 address@hidden



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On Jun 24, 2004, at 8:36 PM, Kennant Tom wrote:

> Hello all,
>
> Does anybody out there know a way that can convert between half-float 
> and float faster than the implementation provided the OpenExr group?
>
> Regards,
>
> Kennant
>
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