From: Tomasz Malesinski <tmal_at_mimuw.edu.pl>
Date: Wed, 14 Dec 2005 00:52:49 +0100

On Tue, Dec 13, 2005 at 02:18:49PM +0100, Tomasz Malesinski wrote:
> I tried playing an Ogg Vorbis song using the original firmware in my
> emulator. Some data appeared in a place that looked like an audio
> output buffer, but when I tried to play them there was only noise. I
> have not yet analysed the codec yet (it is the Tremor decoder, a
> little old and/or modified version). There may be a bug in my emulator
> which causes errors in decoding, but it is also possible that the main
> CPU does not decode the data entirely, for example it is the EPIC core
> that does DCT and the data that I intercepted was not fully
> decoded.

It turned out that it was a bug in emulation of 64-bit multiply
instructions. After I fixed it, the original firmware correctly
decoded a piece of an Ogg Vorbis song, so decoding can be done
entirely by the main CPU.

-- 
Tomek Malesinski

Received on 2005-12-14