The Chuckster has posted some WIP news of his port of Stella the Atari 2600 emulator to the NintendoDS
Wrote DS sound code. Seems to output sound but there's no ring buffer, it's slow (due to a loop with a double), and there's no detectable Atari 2600 bleeps in there. I got some bugs fixed, but of course, it's no where near release.
