grape is an Open Source Apple II emulator for Nintendo DS, powered by devkitPRO, libnds and lots of LemonBoy sweat.

Consider it as a WIP, it lacks some stuff like configurable keymaps and extensive testing. The video generation takes ~50% of the CPU time and would definitely benefit from optimization, beside the fact that it doesn’t emulate color bleeding. When playing games that make extensive use of disk IO disable vblank to make it load faster (eg. Karateka and Pacman).

http://gbatemp.net/threads/grape-an-apple-ii-emulator.356060/