DrSMS is a Sega Master System (SMS) and GameGear emulator for the Game Boy Advance.
It is written in 100% ARM ASM and compiled using the Goldroad compiler.
I have written the Z80 core from scratch using a few ideas from TheHiVE,
which makes it pretty nifty. The Z80 is the main CPU for the SMS just in case you were wondering what it is.
The emulator is still in the early stages of development but already many games are quite playable, check out the compatibility pages to see the progress.