GBA starter kit

You could always install devkitARM and use .s files instead of .c files. I'll admit that some members of NESdev BBS might think a full GNU toolchain (which is what devkitARM is) is overkill. You could take the GBA examples written in C and pass the -S flag to have GCC write the assembly language to disk instead of piping it into the assembler.

You could always do it like I did: just use a hex editor and a little bit of elbow grease And no, I'm not joking, I actually did some programming on the GBA like that (but yes, it is ridiculous).

Doing it by hand with a hex editor is fine for about 4 hours, after that you should never do it again.

Real programmers latch in individual words using toggle switches and a deposit key. If you haven't memorized your program by now then what are you even doing?

It actually isn't bad the way I had it setup. I eventually started writing larger functions by hand and came up with a base "template" ROM so I wouldn't have to keep re-writing stuff. Though for making actual games, a hex editor is a trial in madness. Thankfully I only made small demos to test hardware functionality comparison on an actual GBA vs. emulators. It's a shame though, I have some common THUMB opcodes memorized in hexadecimal.