The GBA's Video RAM is 96k stretching from 0x0600_0000 to 0x0601_7FFF.

The Video RAM can only be accessed totally freely during a Vertical Blank (aka "vblank"). At other times, if the CPU tries to touch the same part of video memory as the display controller is accessing then the CPU gets bumped by a cycle to avoid a clash.

Annoyingly, VRAM can only be properly written to in 16 and 32 bit segments (same with PALRAM and OAM). If you try to write just an 8 bit segment, then both parts of the 16 bit segment get the same value written to them. In other words, if you write the byte 5 to 0x0600_0000, then both 0x0600_0000 and ALSO 0x0600_0001 will have the byte 5 in them. We have to be extra careful when trying to set an individual byte, and we also have to be careful if we use memcopy or memset as well, because they're byte oriented by default and don't know to follow the special rules.

TODO

TODO

TODO

TODO

TODO