Fix Link's Awakening scroll issue.
Replicating it is easy:
- Start a new game
- Go down
- Go left
- Go up
Or just play the game long enough and you'll start to see what I mean. It completely glitches out. Sometimes it's both OBJ's and the bg tiles, other times it's just the bg tiles. The cause is due to writes not being done to update VRAM when the X scroll reg is not 0. I don't know much more than that, and it's proven inscrutable to investigation. I have a hunch it's either a CPU core bug, interrupt bug, or some combination of the two.