Module slots 

Fixed-slot residency policy: a handful of equally sized private arenas, a wishlist, and a stored-then-decoded pipeline.

Lifted from hk-psx game/src/room_residency.rs (a policy independent of the CD transport and of GPU calls) and made generic over the slot count and the wishlist length. The logic and its tests carry over unchanged; what changed is naming (loading is SlotResidency::is_loading, stored is SlotResidency::find_stored, Residency is SlotResidency) and layout. Region ids are plain usize; EMPTY means none.

A slot is empty, being read or decoded (loading), holding completed but unverified bytes (stored, len == 0), or holding a verified room (len non-zero). Only a decoder may turn stored bytes into a verified room, so completed transport data can never be mistaken for one. The current slot, the slot an upload is reading from (protected) and every loading slot are never reused. The wishlist ranks speculative targets: a lower-priority speculative read never displaces an earlier wishlist entry, and an urgent read (the room needed now) may.

Use crate::Residency when payloads differ in size, several pools or categories are in play, or distance should drive eviction; use this when the game keeps a few interchangeable slots.

Structs

Slot

One arena slot.

SlotResidency

Residency over SLOTS arenas with a wishlist of WANTED regions (hk-psx uses 5 and 4: the current room’s slot plus four others).

Constants

EMPTY

Sentinel region id: none.