via http://pdroms.de/gcw-zero/a5200-v1-0-a5200-emu-for-gcwz

alekmaul released a port of A5200 for the GCW Zero. It’s an Atari 5200 emulator based upon Atari800.

http://boards.dingoonity.org/gcw-releases/a5200-v1-0/