Therons Quest Track02 Internals

Theron's Quest Track 02 Internals

Why the Disc Is Not an ISO Filesystem

PC Engine System Card software works with record numbers relative to a CD base. Official Hu7 production places record constants in the executable; the finished disc has no runtime central directory for a game to enumerate. Firestaff uses strict CUE parsing, raw-sector layout validation, known hashes, and traced record transitions rather than filename inference.

IPL and Stage Two

For verified raw JP/US Track 02 media, the IPL executes record 0x0003e7 into local RAM $4000. The subsequent observed CD_READ loads a single sector into $3800: record 0x04df in JP and 0x04e0 in US. The receipt records variant, record, raw sector, MODE1 user-data offset/size, content hash, destination, and live record-register provenance.

The initial $3800 payload begins BRK $ff followed by $0308 and a bounded 218-entry envelope. BRK $ff is control transfer through the active HuC6280 IRQ2 protocol; the subsequent six-byte entries are not executable code merely because they share the loaded sector.

Stage Three Boundary

The stage-two runtime handoff accepts the exact traced record and structural manifest receipt, then rejects a mismatched or mutated record before startup state can advance. This is intentionally transport evidence only. It does not name a manifest entry as a level, object, bitmap, palette, sound, or script.

Startup and Route Transactions

M12 carries strict CUE/Track02 provenance into M11. Startup title, stage, Soul Room, forcefield, and Continue routes require all of their original bitmap and level receipts. Route assembly is candidate-first: a level/object route is committed only after every required data receipt validates. An incomplete route leaves the old runtime state unchanged and cannot fall through to a synthetic surface.

Startup Level Envelope

The authenticated raw JP and US startup payloads agree on the complete 12-byte envelope prefix: dimensions, seed, level index, and an opaque two-byte extension 0x0103 at offsets 10-11. Firestaff fingerprints that extension with the CD-record boundary receipt, but assigns it no gameplay meaning. In particular, it is not treated as a start pose, object count, flag, or command; the following 0x380 user-data tail remains unparsed.

theron_v1_track02_decode_initial_level_envelope() is the real-media decode surface for that one payload. It requires the known raw JP/US hash, IPL INDEX 01 coordinate, descriptor-relative candidate, and MODE1 user-data copy before it promotes the header fields and the exact 0x360-byte grid span. The grid is still byte-faithful and unclassified: no tile meanings, objects, or visuals are inferred. Its receipt explicitly blocks fallback visuals and keeps both the extension and tail unpromoted.

Multi-Level Object Table

theron_v1_track02_read_object_table() now bounds decoded records against the real per-dungeon level count (0..THERON_MAX_LEVELS_PER_DUNGEON-1), replacing the earlier level-0/32x27-only assumption. theron_v1_track02_decode_initial_level_object_table() accepts records for any bounded level, and the new theron_v1_track02_decode_dungeon_level_object_table() extracts a single level's object records from a full-dungeon buffer. Two additional object kinds carry decoded state: THERON_OBJTYPE_SOUND (default THERON_SOUND_AMBIENT_1 for the movement code) and THERON_OBJTYPE_PIT (pit records own their grid position). theron_v1_world_apply_track02_object_table_for_dungeon() routes decoded records to every loaded level of a dungeon, and theron_v1_transition_execute() implements stairs (validated target level), progression advance, theron_v1_world_reset_for_dungeon(), and quest-complete handling at the end of move_party_internal(). This remains real Track 02 data decode, not synthesized object placement.

The loader also exposes a source-category and raw-type census over the opaque category-4..10/14/15 occurrences. This is useful for comparing authentic US and JP media and for selecting the next disassembly target, but it deliberately does not bind category-local type fields to Firestaff item or inventory IDs. That binding remains blocked until the original consumer path is observed.

Authenticated US Descriptor Receipt

The production source layer reads 53 six-byte records from UD 0x619900 in the authenticated US Track 02 MODE1 user-data stream. The focused regression extracts the user bytes from the real BIN and rejects any mismatch against the source-locked table. These records are a provenance receipt for the descriptor bytes only: they do not establish graphics compression, tile-bank ownership, palette binding, object IDs, or the game-owned later-level handoff.

SRM Boundary

Save Disk candidates require one valid gzip member with bounded header parsing, CRC32, and ISIZE validation. Unknown original bodies can be catalogued but are not restored until their structure is independently correlated. Firestaff-native SRM export uses no-replace atomic publication so an original artifact is not overwritten by a test save.

Continue carries the accepted media route mask, checksum, and selected level bank in its receipt. Restore is atomic: bad media, bad gzip, or an unbound body cannot partly mutate the live world.

Verification

FIRESTAFF_THERON_TRACK02_US_BIN=/path/to/us.bin \
FIRESTAFF_THERON_TRACK02_JP_BIN=/path/to/jp.bin \
  ./build/firestaff_theron_v1_track02_ipl_loader_probe

./build/firestaff_theron_v1_track02_level_handoff_probe
./build/test_theron_v1_startup_save_resume_pc34

The next valid semantic step must come from an original loader read, dispatch, or layout correlation for a later record. Repeated bytes, descriptor adjacency, and guessed PC Engine data formats are not sufficient evidence.