[vorbis-dev] Optimisations

[Jason Hecker]

>that we're typically working with data that came from 16 bit samples - so
>really high precision tends to be unneccesary in much of the code. Most of

True enough, signed 16 bit numbers will leave you with plenty of elbow 
room.  Speaking of which, what is the highest number of bits the spec is 
able to handle (I promise I'll read the code carefully for such details 
tonight...)

>That said, there are reasons to use fixed point arithmetic. With modern
>processors, it's usually only a good idea to do fixed point if the
>processor doesn't have a FPU (many/most dsps (including the C6201) are good
>examples here, as you mentioned.) - fixed point is actually typically
>slower these days if the cpu does have a FPU.

That said, I presume fixed point would have to be the choice for x86 
optimisations, as MMX is the only common SIMD instruction set for all post 
1997 x86 CPUs.  Implementation in SSE or 3DNow! would be redundant.(?)  I 
am just looking for an excuse to learn and apply MMX/3DNow (I have a Duron) 
in some sort of constructive fashion. :)

Still, is some sort of optimised (platform dependant optimisations where 
available) DSP library that both the encoder and decoder can use worth it 
at this stage?

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