When we are dealing with arrangement/mirroring, there are 2 important concepts:
- How the end result is arranged, for the purpose of scrolling
- How PPU memory addresses correspond to each nametable.
It seems that most suggestions lean towards one of those or the other, depending on perspective (programmer vs. emulator vs. hardware) or just personal preference. It is probably important to try to do both somehow. Even something so clear for arrangement, such as (v mirroring, h arrangement) doesn’t tell you anything about the PPU address space:
AB
AB
One just has to know that the address arrangement goes top-left, top-right, bottom-left, bottom-right. It seems reasonable that the address space may have gone top-left, bottom-left, top-right, bottom-right. You almost need a second one:
Address Arrangement:
01
23
Graphical Arrangement:
AB
AB
But then someone more hardware oriented might argue that the address arrangement is the one that should change and the graphical arrangement stays constant:
Address Arrangement:
01
01
Graphical Arrangement:
AB
CD
So the question is, how can we generalize address arrangement vs. graphics arrangement, in a way that is short and easy to say?
I think we just ought to have plenty of wiki links whenever we say mirroring or arrangement, and then a page that explains it clearly. Which we pretty much already have.