The most popular toolchain is devkitPro, which is based on GCC: https://devkitpro.org/wiki/Getting_Started https://devkitpro.org/wiki/Getting_Started The impre

The most popular toolchain is devkitPro, which is based on GCC: https://devkitpro.org/wiki/Getting_Started https://devkitpro.org/wiki/Getting_Started The impression I've gotten is that the GBA is powerful enough that you can write most of your programs in C, but some performance-critical stuff (like if you're trying to draw pixels directly instead of using the sprite/tile hardware) is best written in assembly. If you're interested in learning more, I would highly recommend this tutorial: https://www.coranac.com/tonc/text/toc.htm https://www.coranac.com/tonc/text/toc.htm