Porting Test Drive II from SNES to PC, Part 24: Tightening the SNES selector domains and the B1F9 handoff window

Porting Test Drive II from SNES to PC, Part 24: Tightening the SNES selector domains and the B1F9 handoff window The previous checkpoint created the first DOS-driven SNES front-end contract set. That was useful, but still soft in two places: the selector domains were only loosely named the bank-1 handoff candidate near L009568/L0095AD was structurally plausible, but still blurry around the real gameplay callback chain This checkpoint tightened both without pretending they are solved. The four-state selector is now more concrete The strongest static gain came from decoding the small table at 01:8000/01:8008. That table is the source for $1C7E/$1C80, which means it drives the row base and row count used by the shared front-end descriptor builder. It now decodes cleanly as: bases: [0, 5, 11, 18] counts: [5, 6, 7, 8] So $1C7C is not just “some four-state knob.” It is a verified four-group descriptor selector. That still does not prove the human label is “track” or “scenery,” but it does el