This is a GameBoyAdvance demo that I made during my first few months at Ai-VB around November 2002. I studied the GBA architecture and learned how to program for it over the course of a couple weeks.
This demo show the direct use of the backbuffer in mode 4, a scrolling tile map made in using an external map editor and sprite animation using external graphics.
I programmed using full C++ in Visual Studio 6 and added the final compilation as a post build step. Using BoycottAdvance I was also able to test the demo as if it was a full Visual Studio project. The full source includes a copy of BoycottAdvance and devkit Advance which was used to make the Game Boy bin files. The demo was actually copied onto a GBA cartridge and tested to work on an actual GBA unit.
GBA Bin File
VC6 Source Code (Cannot be built on it's own)
Source and build tools (See Note)

Boycott Advance
Devkit Advance
GBA Development
NOTE: Because of the requirements of building the GBA the second Source file also includes devkitadv (50 Megs uncompressed). To complete the experience I also included a copy of boycott advance. With these extra tools you can open the project in Visual Studio 6, compile and run the demo without the having to leave VS6.

[Oct30, 2005] At the time that I did this everything was all legal and ok. I'm not sure what the status is like as Nintendo has made some fuss over GBA emulators since I did this.