Fixed point matrix representation considered harmful
simon.thum at gmx.de
Thu Mar 20 14:41:56 PDT 2008
Joerg Sonnenberger wrote:
>>> Except that it complicates decoding for non-IEEE platforms. Think VAX.
>> Are we actually designing for VAX these days? There aren't many other
>> non-IEEE platforms that I know of: even lame embedded/consumer chips are
>> pretty much all IEEE now, TTBOMK.
> Well, at least some of the RISC platforms have IEEE-like floating point,
> but don't do the magic values. Think about Alpha. My point is to just
> specify a simple binary format and leave out all the special magic
You'll have to do sanity checks independent of the platform. It's
actually quite hard to avoid special values by (re)specifying the binary
representation. How to make denorms unrepresentable?
IMHO: Much pain, no gain.
That leads me to the question if threre is any policy or precedence on
float-over-wire? I could really use it if it was officially blessed. A
quick grep gives me glxproto.h and some floats in
xf86vidmodeproto/xf86vmode.h. Is there any 'official' policy on this?
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