Rockbox

This enabled SPC files to be played with echo on PortalPlayer targets like iPods and Sansa. It operates in a pipelined manner by running emulation on the COP and audio output on the CPU. Comes with a few asm optimizations to help out a bit though most help is just from the parallel processing.

Only reason this won't go into SVN right away is that there is no compatibility with voice. There is no facility to swap-out multithreaded codecs -- multiprocessor or otherwise. I plan to address this since I think codecs should have full control over their processing setup. The piplined method should be preferred for especially intensive codecs anyway.

This will compile for single core ARM and Coldfire as well and doesn't create the extra thread in that case.
Single-core ARM still gets the asm tweaks.

 apps/codecs.c               |    2 
 apps/codecs.h               |    8 
 apps/codecs/spc/spc_codec.h |  100 +++++++++---
 apps/codecs/spc/spc_dsp.c   |  232 ++++++++++++++++++++--------
 apps/codecs/spc.c           |  353 +++++++++++++++++++++++++++++++++++++++-----
 5 files changed, 571 insertions(+), 124 deletions(-)