4.0 Creating the Software

There are several tools to write programs in different languages for the GameBoy^TM and all are freeware! I have found a Basic-interpreter, a C-compiler and different assemblers. When writing programs an emulator can be very handy for testing prior to burning code into EPROM. Several emulators and tools are described in this section.

4.1 Software (development) Tools

Emulators and other useful programs

NO$GMB - one of the best emulators for developers. Allows stepping through programs while viewing registers, etc.

GB 97 and VGB - Two GB emulators running under DOS or in the Windows DOS-Box

VGB-MAX - A very good frontend under W95. To use it with GB97 rename GB97.EXE to VGB.EXE

Development tools

GB-Basic - A real Basic with all its advantages and disadvantages, which runs both on the real GameBoy^TM and on the emulators
The problem of writing GB-Basic programs on the GameBoy^TM is that you have to key them in with the six keys of the GameBoy^TM and that there is no way to save the files on the GameBoy^TM permanently (they can not be burnt to a ROM either). Also it is not possible to modify existing GB-Basic code. Jeff has still some work to do on this tool.
An alternative method is to use a PC with a text editor (like DOS edit) and GBBC the next tool in this list. To implement improved file handling I wrote some batch files. To transfer the basic - programs form you PC to the GameBoy^TM requires modification of a MBC1 cartridge (with RAM onboard) and building the GameBoy^TM to parallel port cable. For more details have a look on Jeff Frohwein's page.

GBBC - converts an ASCII-text file into an GBB binary and GBB binary into ASCII (see the batch files below)

The GB-Development Kit (V2.0) includes a C and an assembler compiler, linker and builder.
It is absolutely vital to install the Development Kit into the root directory of your hard disc. To avoid this use the "subst" command as shown in the next batch file example. Programs can now be written using a text editor. Use the extension „C“ for a C-source file and „S“ for an assembler-source file.

The Gameboy Development Studio is a IDE (Integrated Development Environment) for GBDK 2.0 and Windows95^TM. Check out the site for further features.

Table x: some useful batch examples