GBA Bootstrap

This is an example of a minimal project for GBA that can be built with a vanilla gcc-arm-none-eabi toolchain. This repository contains all the source you need to get started.

There is an example of the codebase using just C and an example of using C and C++. Feel free to modify anything as you wish to suit your needs. This is meant to be a relatively simple to understand template for anyone to use as base.

The license of the files in this repository is CC0 1.0 Universal, so you can treat all the files as if they were in the public domain.

For an up-to-date version of this repository, check the GitHub repository: https://github.com/AntonioND/gba-bootstrap

Instructions

You need the gcc-arm-none-eabi toolchain. If you're on Linux you can just use your package manager. For example, in Ubuntu:

sudo apt install gcc-arm-none-eabi

This will add the compiler to your PATH as well.

You can also download prebuilt binaries from Arm's GNU toolchain downloads website. In this case, you will need to manually add this toolchain to your PATH.

Then, from the folder of either of the samples, type:

make

That's all!

Organization

For both samples the organization is the same:

• Makefile: Global makefile.
• gbafix: Tool used to fill the checksums and other required fields of the ROM header.
• source: All the source code of the game goes here, including yours.
• source/sys: Files required by the C/C++ runtime.
• source/sys/gba_cart.ld: Linker script that describes how code and data sections are placed in the ROM and at runtime on the GBA.
• source/sys/gba_crt0.s: Initialization code that loads each section into the right location in RAM.
• source/sys/syscalls.c: Implementation of system calls. They are all stubbed, so you can't use things like printf() or fopen() unless you implement them, which isn't usually worth the effort on GBA. For more information, check: https://sourceware.org/newlib/libc.html#Syscalls