Getting the GBA to do things often involves the use of the so-called IO registers. Certain bits at certain addresses of memory can be used as switches for the various effects that the GBA is capable of. Each register is aliased as a normal variable, and you need to set/clear bits using bit operations. We'll get to where these registers are and what bit does what later; right now I want to show you how I will present these, and refer to them in the text... If you are new and have followed the other tutorials, everything will seem to work fine, so what's the problem? Well, that's part of the problem actually. Everything will seem fine, until you start bigger projects, at which time you'll find hidden errors and that slow code really bogs things down and you'll have unlearn all the bad habits you picked up and redo everything from the start. The GBA is one of the few platforms where efficient coding still means something, and sometimes all it takes is a change of datatype or compiler..
Also known as: gbadev