[Speex-dev] Speex on a Blackfin DSP

Jean-Marc Valin jean-marc.valin at usherbrooke.ca
Wed May 2 03:41:49 PDT 2007

> Which we are constantly working on. We do have some targetted pieces of C 
> code, that we noticed could be done better, and are in process of working on.

David Rowe actually had some details about optimising Speex here:

Some of the issues we found:
- Enabling write back helps a lot
- There *probably* is I1 cache trashing because we don't use the I1 SRAM

In terms of gcc some of the things that *probably* have the most impact:
- No hardware loops
- No conditional moves
- No MAC instructions
- No parallel loads

The last two mean that an inner product ends up looking like:
instead of
mac | load | load

All that is based on observations from last year. Things might have
changed since then.


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