[speex-dev] Speex on Nokia 6600

[Jean-Marc Valin]

Le ven 23/01/2004 à 18:55, Grzegorz Kulewski a écrit :
> Hmm, what these instructions do? (I know nothing about ARMs; I have some 
> knowlege about x86 assemblers and programming). 

These are dsp-like instructions. For example, one of them replaces 4
instructions by doing a 32 bits x 16 bits fused multiply-add. I know
they're available on xscale, but I don't know about other ARM cores.

> Cant we use pure standard C++ or Java? 

Sure, the assembly is only for some parts where there's a potential gain
in speed.

> Does Speex work with fixedpoint math? (As far as I know Java 
> on 6600 has no builtin floatingpoint, there is emulation class somewhere 
> on the net, but it is probably painfully slow.) I do not know if this 
> processor has builtin floatingpoint math module.

Speex uses fixed-point arithmetic. Otherwise, it would be about 100
times slower than real-time.

> When "current" code would be able to do it in Your opinion?

I have no idea. You have to test that. If the multiply-add and similar
operations are supported, it might be already possible. Otherwise, there
would be some optimization to do. Right now, Speex is about 5x faster
than real-time on a 400 MHz xscale.

        Jean-Marc


-- 
Jean-Marc Valin, M.Sc.A., ing. jr.
LABORIUS (http://www.gel.usherb.ca/laborius)
Université de Sherbrooke, Québec, Canada


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