Month: April 2003

Mappy 0.9d is the 4th release of the Mappy Virtual Machine and the first release to be Open Source. The complete source code to both the Mappy VM user interface and the Mappy VM core is available under the Bottled Light Public License, similar in terms to the MPL.

The binary version of Mappy VM 0.9d is an interim release to accompany the source code. In addition to a number of bug fixes, 0.9 is also considerably faster than 0.8. Most of the viewers have also been improved and the source debugger has been rewritten from scratch.

More information, binaries, and source code can be found at http://www.bottledlight.com/mappy

Mappy VM is a fully featured virtual machine which behaves very similar to the Gameboy Advance from Nintendo. It fully supports the CPU, input hardware, all graphics modes, DMA with correct timing, and many aspects of the sound system. Both a compiled version and the complete source code can now be downloaded from the Mappy VM website. However, it needs a BIOS image from a GBA for proper operation, as the included stub BIOS only includes an IRQ handler.

Mappy VM also provides an extensive suite of tools to assist developers in debugging and developing their games:

• Breakpoint List
• Console
• Disassembler
• IO Register Viewer
• Memory Editor
• Palette Viewer
• Sound Viewer (prototype)
• Source Debugger
• Sprite Viewer
• Video Viewer
• Watch List

All of the viewers are updated in realtime as the simulation progresses, and most of them have editing capabilities. Being able to pause a simulation and edit system conditions can be extremely useful in attempting to reproduce bugs. In addition, Mappy VM also supports

saving or restoring the entire system state, making it easier to debug problems that only occur after several minutes of gameplay or to test multiple hypotheses.

A number of pictures from the current version (0.9) can be seen in the online help.