This will be a web-based DCPU-16 emulator, from Mojang's new game 0x10c.
I am following the spec posted by Notch.
You should be able to use the app here: http://mappum.github.com/DCPU-16.
So far, this app can compile code, but it's possible there are mistakes. Notch's example code compiles correctly. I have not yet tested this very thoroughly, so if you find anything, feel free to open a ticket.
I will finish the code execution next.
The current UI is just for getting the emulator code to work. I will try to make a real editor soon.