[speex-dev] Speex on Nokia 6600
Jean-Marc.Valin at USherbrooke.ca
Fri Jan 23 20:59:39 PST 2004
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
> 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 Valin, M.Sc.A., ing. jr.
Université de Sherbrooke, Québec, Canada
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