# RE knowledge index

Confidence: ✅ `CONFIRMED` · 🟡 `PROBABLE` · ❔ `HYPOTHESIS`. See [README](README.md).

Formats we've already reversed are, for now, **documented by their parser + disc round-trip
tests** (the executable spec) rather than a prose file — the "Spec" column points there.
Promote to a prose `structures/…md` file when a format needs behavioural notes beyond layout.

## Data structures / formats

| Format | Conf. | Spec (parser + tests) | Notes |
|--------|-------|-----------------------|-------|
| IPFB `.pak` archive | ✅ | `sylpheed-formats/src/pak.rs` + `tests/pak_idxd_disc.rs` | header + 12-byte TOC, Z1/zlib payloads |
| name-hash (TOC keys) | ✅ | `sylpheed-formats/src/hash.rs` | Barrett-reduction hash; recovers original paths |
| IDXD object/table | ✅ | `sylpheed-formats/src/idxd.rs` + `tests/idxd_records_disc.rs` ([container](structures/idxd-container.md)) | **The binary record/index region in front of the string pool is DECODED** (2026-08-25), closing the parser's long-standing "not yet decoded" note. Uniform 16-byte records `{name_hash, name_off, field_begin, field_end}` sorted by hash and binary-searched, then a field count, 12-byte fields `{key, name_off, value_off}` sorted by key, a pool size, and the string pool; the trailing `pool_size == file_len - pool_base` identity makes the layout self-checking. Verified over the **whole disc** with **zero** failures: 7 750/7 750 objects, 190 782/190 782 records reproducing their stored `tag_hash`, 1 271 462/1 271 462 named fields reproducing their key — and `IXUD` is the same container with `ixud_hash`, UTF-16BE and all offsets in **chars** (1 104/1 104 objects, 628 165/628 165 fields). **Field names are stored on disc** — a field's middle word points at its own name — so nothing needs preimage search except the **504** fields disc-wide that are hash-keyed with no name; the other 1 485 073 nameless fields are *positional*, keyed by a literal integer (line slots, movie ids). ⚠️ **Two long-held beliefs WITHDRAWN**: the word at `0x08` is **not a schema hash**, it is record 0's `name_hash` (7 750/7 750) — the header has no type field at all, so an object's kind is known only from the caller that loads it; and the field's middle word is **not** an always-`0xFFFFFFFF` flags word. The first was caught by a test asserting that every movie id names a real record: `1005 -> STAGE10_PHASE01` failed because `tag_hash("STAGE10_PHASE01")` **is** `0x067025B9`, that table's supposed schema id. 🟡 the legacy value-before-key string-pool reader is now known to be an *approximation* of the real table, and every number derived from it is re-checkable but not yet re-checked |
| XPR2 texture + cubemap | 🟡/✅ | `sylpheed-formats/src/texture.rs` + [colour check](xpr2-colour-check.md) | de-tile + A8R8G8B8 and DXT1. **Channel order ✅ confirmed against the running game**: the Delta Saber's decoded atlas is orange-dominant (median saturated hue 23.3°, *zero* cool pixels) and the game renders the same hull at 9.3° — a red↔blue swap would sit at ≈200°. Exact fidelity (gamma/sRGB curve, premultiplied alpha, per-channel scale) is 🟡 untested, since a hue comparison cannot see it; cubemap face ordering ❔ |
| T8aD 2D texture | ✅ | `sylpheed-formats/src/t8ad.rs` | **100 % of the disc decodes** (19 216/19 216, measured). The "~15 % deferred variants" were a wrong model, not a variant: a surface is a list of **arbitrary sub-rectangles**, each with a 16-byte header of `dst X, dst Y, width, height`, not a 256×256 grid — `0x1c` is the **rectangle count**. Uncovered area stays transparent. **Colours ✅ CONFIRMED** ([k8888](structures/texture-color-k8888.md)) |
| RATC bundle | ✅ | `sylpheed-formats/src/ratc.rs` | child listing confirmed. **"One level deep" is not a limitation — there is nothing deeper**: 2 859 bundles hold 18 002 children at depth 1 and **0 at depth 2**, with no parse failures. Nested RATC blobs are **leaf records that reference siblings by name** (`opt `, the sprite name): 3 311 leaves, all embedding sibling names, **10 144 of 10 148 references resolve**. The 4 that do not are one dangling asset — `pmbase.rat` → `pmbase.t32` in `GP_STAGE_CLEAR.pak`'s four language builds, and `pmbase.t32` is **on the disc nowhere** |
| LSTA sprite list | ✅ | `sylpheed-formats/src/lsta.rs` | A display list of inline elements: **T8aD sprites and `PRMD` primitives**. The `count` at `0x04` is **exact and counts both** — `count == T8aD + PRMD` for **64/64** lists on the disc, which retires the old "a few entries disagree" note (it compared sprites against a total including primitives). **All 1 281 sprite frames decode** after the T8aD rectangle-list fix |
| IXUD subtitle | 🟡/✅ | `sylpheed-formats/src/ixud.rs` + [movie link](movie-subtitle-link.md) | timed cues. **The movie↔subtitle↔voice link is solved — statically**, from the movie config record in `tables.pak` (schema `0x067025b9`), not from the running game as this row previously assumed: [101 movies mapped](captures/movie-subtitle-voice-map.csv), 94 with subtitles, 83 with voice, 21 with a telop overlay. 93 of 94 subtitle refs resolve in the language paks; **`SUBTITLE_S12B.tbl` is missing from all six languages** — a dangling reference on the disc. Naming is `SUBTITLE_<base>.tbl` / `VOICE_<base>` with six documented exceptions. The record's ~104 **script ids** are ❔ — positional pairing drifts by three because the IDXD pool dedupes repeated values |
| Fonts (ttf/otf/ttc) | ✅ | `sylpheed-formats/src/font.rs` | standard OpenType, parsed via ttf-parser |
| XBG7 mesh | ✅/🟡 | `sylpheed-formats/src/mesh.rs` + `tests/mesh_disc.rs` ([xbg7](structures/xbg7-mesh.md)) | **6 294 resources, 6 209 decode (98.7 %), 82 searched-and-missed** (2026-08-12, up from 5 480 / 87.1 %). Five evidence-driven fixes got there: **distinct anchor assignment** (no two resources may claim one buffer — proved by a capture showing the container holds both mirrored `e106` hull halves), the connectivity cap replaced by a **winding-consistency gate at 0.70**, **structural requirements on pre-pivot sub-meshes** (index range, then exact pool coverage), and **filtering after the assignment** so a subset query cannot differ from the full decode. Validated against a runtime capture that names the file offset of every buffer the engine drew: **46/46 drawn buffers claimed, 45 anchored exactly**. **No real mesh now decodes differently in different containers** — all 89 remaining cross-container disagreements are interchangeable 24-vertex bounding boxes, which no anchoring rule can pin (monotone order re-tested and refuted). Remaining misses attribute to the degeneracy/extent gate (42), winding (31) and coverage (9); the first was probed and its "obvious" fix refuted. Every decoded sub-mesh covers its own vertex pool. **The `[index buffer][vertex buffer]` layout is now runtime-verified** (2026-08-13): with the F10 capture extended to log each draw's index buffer, all **42** drawn `Stage_S02` buffers match our decoded index count exactly, all 42 have their index union cover the pool exactly, and the 30 single-block cases all sit at `pad ≤ 3` — so `e106_eng_02_l`'s old rejection was the connectivity gate, not a misplaced index buffer. The `indices=` mystery was the capture keeping only the **first of several index batches** per buffer. **And comparing index VALUES found the biggest silent defect yet**: the anchor took the first `pad` that validated, so a block whose index data sits at pad 2 was read **one element late** — 76/93 captured runs matched, all 17 differences a one-element shift. Scoring pads by degenerate triangles + winding fixes it: **93/93** captured runs now match byte for byte, disc-wide degenerate runs **582 → 1** (the grouped path had the same bug; and two resources were anchored on a degenerate lookalike earlier in file order), **590 of 8 850** sub-meshes re-wired with 10 vertex anchors moved, resources decoded unchanged at 6 209. Cross-container minority decodes 89 → 96 — *because* the decoder improved: `_rou_f402_dead` now has a majority (32×25×8) so its seven wrong copies are named instead of hidden. One dirty run remains, blocked by distinct assignment on a 24-vertex box. **Then the descriptor gave up its last structural secret**: it declares a vertex layout **per sub-mesh** (`n201_01` → strides 24/24/24/**28**, capture-confirmed), and grouped selection must prefer the candidate explaining the **whole** pool rather than the first whose pivot validates — together they take never-decoding resources **85 → 47** (**6 247 / 6 294 = 99.25 %** decode), put `n201_01` on all four capture-proven offsets and raise the stage-05 capture oracle to **128/128**. The residual 47 is 30 pose/proxy composites (0.010-unit marker boxes), 6 `.DAT` particle composites, 8 damage/LOD variants and 3 props — not a threshold away |
| Capital-ship part placement | ✅ | `sylpheed-formats/src/ship.rs` (static) + [runtime capture](ship-placement-runtime-capture.md) | Placement is **sound** (hull static-exact against the `e106` capture; cross-id mounting genuinely narrow, 2 pairs across 335 ships). The XBG7 mis-decode this row used to blame for "ships assemble wrong" — a shared turret ~100× too large in some containers — is **fixed** (2026-08-12, the exact-coverage requirement): `e303_wep_01` now decodes 49×23×42 everywhere and places at ±179 on the `e106` hull, and no real mesh disagrees across containers. A composite-node audit confirmed the assembler itself never applied a bad scale (all nodes scale 1.0, orthonormal). Still open: `static_assembly_matches_runtime_capture` walks capture parts only, so **extra** static placements cannot fail it |
| Weapon fields defaulted on disc | ✅ | [runtime struct](structures/weapon-struct-runtime.md) · [DATA SHEET route](weapon-datasheet-runtime.md) | **Solved.** Canary maps guest RAM into `/dev/shm`, so the parsed `Weapon`/`Shell` objects are readable live; their layout is solved against disc ground truth (zero contradictions over 100+ records). All 126 weapons, exact numbers, no story progress needed — [4 393 values](captures/weapon-runtime-fields.csv) the disc does not carry. Supersedes the letter-bucket limit of the DATA SHEET route, which now serves as the independent cross-check |
| Unit (craft/vessel) fields defaulted on disc | ✅/🟡 | [runtime struct](structures/unit-struct-runtime.md) | The parsed `unit\UN_*.tbl` definition object, vtable `0x820af844`, ≥`0x380` bytes, one per unit — **discovered, not assumed** (`unit_discover.py`), and distinguished from the spawned-entity class `0x820af030` by being one-per-ID and byte-constant within a run. Across runs only pointer words move — `--crosscheck` proves **no reported field offset is run-dependent** (two words, `+0x2c8`/`+0x2d0`, are stage-dependent and remain unidentified). 27 fields ✅ (21 units, 7 runs); the `Maneuver` block is **schema declaration order, 4 bytes/field, base `0x9c` with a two-slot gap after `AA_Roll_Min`** (29 anchors, 0 conflicts), which also pins 5 fields *no* disc record ever values. Angles are **radians at runtime, degrees on disc**. **Re-derived independently 2026-08-13 from the loader's own key strings** (`sub_82341A20`; the field name for each store is a string in the image): **159 fields**, agreeing with this solver on **25 of 25 shared offsets**, verified at **406 values matching the disc and 0 disagreeing** over 11 live objects spanning UNIT and VESSEL — landed as `data/unit_definition_layout.txt` + `sylpheed_formats::unit_layout` + a no-emulator test, with **121 defaulted fields** read out ([live-unit-definitions](live-unit-definitions.md)). Unlike weapons, unit definitions are instantiated **per stage**, so coverage (21/110) grows by visiting missions — but a defaulted field is **not** a global constant: `Size_Y` provably inherits `Size_X` (7 independent units, 6 distinct values), and three more sibling rules are recorded ❔, recovering 65 values in units never visited — [values](captures/unit-runtime-fields.csv) |
| Arsenal develop economy | ✅/❔ | [arsenal-develop-economy](arsenal-develop-economy.md) + [conditions](captures/arsenal-develop-conditions.csv) | The Arsenal reads `weapon.tbl` (item ids, in the 8-category display order) and `strings.tbl` (names, descriptions, and a **"Conditions to obtain"** block per item) out of `GP_HANGAR_ARSENAL.pak`. All **60** conditions are extracted: gates are stage completion, a predecessor item, or an **ace kill**; costs run 3 000–350 000 P and **20 items are free** once gated. `weapon.tbl`'s first record reproduces the in-game DATA SHEET exactly (Range D / Power E / Speed – / Weight 0.3 = Light / 4000 P) — later records are unreadable from the string pool alone because IDXD **dedupes repeated values**. Used to identify the save blob's index space, now **solved**: the blob follows **`strings.tbl`'s** order — the display order *plus* the cut items only the localisation file lists (`Adhesive Mine B2A`, `Ballista GSH`, …) — pinned by four hand-written probe saves (9 Stiletto, 21 Falcon, 39 Tomahawk, 48 Jamming System) and closing exactly at index 53. `weapon.tbl`'s id list is **not** the index space; that it is also 54 long is a coincidence, and the two agree only to index 32. The retail save's five unexplained owned entries are the cut items, shipped owned and never rendered |
| UI screen layout (`.rat`) | ✅/🟡 | [ui-rat-layout](structures/ui-rat-layout.md) | One pak per UI screen; each RATC = one (context × language) build; every `<name>.t32` sprite has a `<name>.rat` **layout record** (BE u32; 1280×720 design space; scale/tint/X/Y, keyframes for animated elements, `opt ` link to the focused state). **The tutorial PAUSE menu and the title main menu both rebuild pixel-accurately from the disc.** `loop1.rat` is decoded — it is a **looping sprite animation**, not a composition. ⚠️ **DEMOTED 2026-08-18** — the declaration table is *not* the paint order: a per-draw capture of the running title screen ([ui-title-paint-order-capture](ui-title-paint-order-capture.md)) paints element 13 first and elements 0/1 late, and the visible screen composites two bundles. The rest of the table's reading stands. Previously claimed: the **screen's draw list is the RATC bundle's own declaration table** (elements in back-to-front order, including the `eff*`/`deli*`/`msg` sprites that have no `.rat`, and excluding focused button variants reached via `opt `); its entry also carries a **parent element index** at `+32`. **A screen is fully reconstructible from its bundle**: the placement region right after the declaration table gives every element a keyframe group (header = element index + keyframe count, then 40-byte blocks of scale/tint/X/Y), including the `.rat`-less sprites — verified 11/11 on the tutorial pause bundle, with `pgp_ttrl_btn10`'s inline (546,288) matching its own record exactly |
| UI screen paint order | ✅ | [runtime screen object](structures/ui-screen-runtime.md) + [title capture](ui-title-paint-order-capture.md) | **SOLVED**: the game's screen object keeps a second, reordered list of its elements — the child array at `+0x30` — and that is the paint order, not the declaration table. Read live from guest memory (found by the item vtable `0x820b30b4`) and checked against the draw capture: the seven nameable elements sit at child slots 0, 6, 7, 13, 16, 17, 22, strictly ascending, exactly as captured; it also settles the one pair no static field could order. 🟡 deriving that order from the bundle — what the port needs — is still open |
| Scripted input / profile traps | ✅/🟡 | [canary-scripted-input-traps](canary-scripted-input-traps.md) | Why a scripted run appears unable to press Ⓐ: **F10 opens the emulator menu bar**, and any Xenia UI makes `XamInputGetKeystrokeEx` return SUCCESS with an empty keystroke *before* any driver is asked (Canary now logs `[RE-INPUT] … swallowed by IsUIActive`); the title needs a **signed-in profile** (hence `--create_profile_if_none`); and a **FIFO trace consumer that exits stalls the emulator**, which reads exactly like a dead pad. 🟡 The main menu HAS been reached — Ⓐ works, but only intermittently (1 in ~4), which is the open question |
| Title-screen guest crash | ✅ | [title-crash-stl-tree](title-crash-stl-tree.md) | The guest throws **`std::out_of_range`** from its cache-manager flush (`sub_823070B0`, an STL map/set erase that builds `'invalid map/set<T> iterator'`); the access violation after it is only the throw **returning**, because this build does not unwind guest EH. Trigger found and controlled: an **incomplete on-disc cache** (`~/.local/share/Xenia/cache/aab216c3`) throws ~100 s into a boot, a complete one never does — 2 runs each way. ❌ `mem_watch`, the handoff's suspect #1, is **eliminated**: cold cache + `--mem_watch=false` throws anyway |
| Save file (`savedata`) | ✅/❔ | [savegame-format](structures/savegame-format.md) + [`tools/re-capture/savegame.py`](../../tools/re-capture/savegame.py) | `GDHA` container, zlib payload, chunk stream (`GDAA` / phase name / `GHAD` 122 B progress block / 16×20 B slot table / trailer). **Container and layout read off the title's own serializer `0x822C00E8` and verified by a byte-identical round-trip**; the whole save is 545 B. Payload offsets are also the live save object's offsets (`save+8` GHAD, `save+136` slots). A second save made in-game names **Points** (+24), **flight time in ms** (+4) and **clear ratio %** (+8) off the game's own Details panel; the payload is a **pure function of game state** (same state saved twice = byte-identical, only the header FILETIME and its uninitialised pointer padding move), and the 16 `SHAB` records are **not** the UI's 20 save slots. Difficulty vs stage is undecided — three fields hold 2. **A third save, taken after developing exactly one Arsenal weapon** (Light Machine Gun MG I, 4000 P), moves exactly three things: `+24` Points 4101→101 (which **separates it from `+28`**, that did not move), `+8` clear ratio 5→6 (so the ratio counts *collection*, not only stages), and two entries of the 54-byte blob — `2→4` for the item bought and `0→2` for the successor the game announced as newly developable, giving the blob its alphabet ✅ *0 locked / 2 developable / 4 developed* (only the `4`s are stored — `2` is re-derived at load). **Saves can also be written back**: three derived header fields (length at `+0x30`, payload length at `+0x8c`, `adler32` at `+0x8e`) are all that stand between a parse and a hand-written save that the title loads, and [`savegame_edit.py`](../../tools/re-capture/savegame_edit.py) re-wraps a real save byte-identically. That turned the blob's index space from blocked-on-story-progress into four probe saves — see the [economy note](arsenal-develop-economy.md) |

## Runtime / dynamic-capture technique

| Technique | Conf. | Spec | Notes |
|-----------|-------|------|-------|
| Scripted input without a virtual controller | ✅ | [`tools/re-capture/pad.py`](../../tools/re-capture/pad.py) + Canary `--hid=file` | The old `vgamepad` path created its device through `/dev/uinput`, which is **not namespaced** — a pad made inside the container registers with the HOST's input stack, so every scripted press leaked to the desktop. Canary now carries a header-only driver that reads pad state from a **text file** (`--hid=file --pad_file=…`): no kernel device, nothing leaves the container, and analogue values are exact. ⚠️ The trap: 360 menus poll **`XamInputGetKeystrokeEx`**, not `GetState` — with `GetKeystroke` stubbed the pad looks completely dead on a title screen while its own log shows the press arriving. Implemented edge-triggered, no auto-repeat (scripted input wants one event per press). Proven end to end: boot → title → main menu → EXTRAS from the file alone |
| Live guest-memory write | ✅ | [`tools/re-capture/gpoke.py`](../../tools/re-capture/gpoke.py) | Write companion to `gmem.py`, same guest-VA → `/dev/shm` map; prints before/after per word. Used to confirm the challenge gate's cleared-stage mask on the running game |
| Live guest-memory read | ✅ | [`tools/re-capture/gmem.py`](../../tools/re-capture/gmem.py) | Canary backs the guest address space with `/dev/shm/xenia_memory_*`; guest VAs map in through Xenia's fixed table. Full-RAM search ~0.2 s (sparse, `SEEK_DATA`). No debugger, no emulator patch, game keeps running |
| IDXD object layout solver | ✅ | [`tools/re-capture/weapon_runtime.py`](../../tools/re-capture/weapon_runtime.py) | Scan RAM for a class's vtable → enumerate its objects → brute-force `(field, offset, encoding)` against the disc records. Accepts a binding only on **zero** contradictions. Generalizes to any IDXD-backed definition |
| Live entity state, anchored on the definition | ✅ | [`tools/re-capture/own_state.py`](../../tools/re-capture/own_state.py) · [autopilot](autopilot-memory-driven.md) | An undamaged craft holds its definition's own numbers, so a *solved definition field* locates the matching live field without a value scan: definition `HP` (1500) → **hull at `position+0x154`**, confirmed by a trace across a death (30/60/90 per hit, negative at 0). Reusable for any live counter whose maximum the definition carries |
| Mission / escort state, every entity's hull | ✅ | [`tools/re-capture/mission_state.py`](../../tools/re-capture/mission_state.py) · [escort state](mission-escort-state.md) | `hull = position + 0x154` is a property of the **entity class**, not of the player object: at t=0 it equals each entity's own definition `HP` across 7 classes and 5 distinct HP values (turret 100, fighter 500, destroyer 10000, cruiser 30000, **ACROPOLIS 25000**), falls under fire (780 damage events in 240 s), goes negative at death, and the object then leaves the heap. So an escort objective is scoreable live — `UN_f101_TCAF_Acropolis` measured at 25000 → 23038 over 240 s, attack starting only at t≈170 s. `REMAINING OB` counts objectives, not hostiles (012 on the HUD vs 118 live ADAN); its address is still ❔ |
| In-flight control mapping | ✅/🟡 | [`tools/re-capture/fire_probe.sh`](../../tools/re-capture/fire_probe.sh) · [controls](flight-controls-runtime.md) | Measured by holding each pad input and photographing the HUD ammo counters: **`RB` = nose gun** (6000→5956 in 4 s, ~11 rounds/s, HEAT rises), **`Y` = main mount** (missiles, 300→299), d-pad = **tactical map** overlay, nothing else moves a counter. No target-cycle input exists — the `TARGET` marker is present with nothing pressed, so targeting is automatic and a missile lock is **time-on-target**. That, not target choice or ballistics, is what caps lethality at 2 kills per 98 missiles |
| Throttle → speed law | ✅/🟡 | [flight-speed-law](flight-speed-law.md) | **The throttle selects a TARGET SPEED**, it does not add thrust: no input settles at ~420 (`CruisingVelocity` 350), `RT` at ~1 530 (`MaximumVelocity` 1200), `LT` at ~125 (`MinimumVelocity` 100), and releasing either returns to cruise. `Acceleration`/`Deceleration` govern the convergence rate (measured ~440–560 units/s² against 500/600). 🟡 measured world speeds run ≈1.2–1.3× the definition numbers while the HUD shows the definition value exactly, so world units are a constant (~1.25) multiple of the definition's velocity unit |
| Input → dynamics calibration | ✅ | [`tools/re-capture/ctrl_probe.py`](../../tools/re-capture/ctrl_probe.py) · [`binq.py`](../../tools/re-capture/binq.py) | Hold each pad input in turn and measure the craft's speed as displacement/s of its own position triple — no speed field needed first. Settled the throttle: **`RT` accelerates, `LT` brakes, and the setting persists** (488 → 1510 → 174 units/s), overturning an earlier field-scan conclusion |

## Functions / code paths

| Function | Conf. | Reimpl. | Summary |
|----------|-------|---------|---------|
| Achievement table + XAM read path | ✅/🟡 | [achievements](structures/achievements.md) | The XEX's `XACH` resource (`.pe` `0x8FBCBC`, 36-byte records) defines **24 achievements summing to 1000G** — the retail total, which self-checks the stride and field offsets. `GamePart_Debriefing` (`0x8218CF38`–`0x82191B18`) does two things: it walks the on-disc `ACHIEVEMENTS_REQUIREMENTS` list (`tables.pak` #16, entries `ACHIEVEMENT01…24`, in achievement-id order — its `ShootDownAircrafts`/`ShootDownShips`/`ShootDownWeight`/`GetAllWeapons`/`GetAllAchievements` types line up with ids 19–24 exactly as `XACH` names them), evaluating each and setting a bit; **and it enumerates `XACHIEVEMENT_DETAILS` from XAM** — 36-byte records confirmed by the `0x38E38E39`+`srawi 3` divide-by-36, `dwId` at `+0`, `dwFlags & 0x00020000` (`…_ACHIEVED`) at `+32`, behind a waited-then-closed async handle. **So earned state comes from the console profile, not the 545-byte save** — and the masks it builds are `1 << dwId`, i.e. **bit = the 1-based id**. **The challenge missions do NOT gate on this** — an earlier claim here, refuted by finding `+80`'s sole writer: it is `GamePart_StageClear` setting `1 << stage`, so that word is a *cleared-stage* mask and the shared "24" was a coincidence. `GetAllAchievements`/`GetAllWeapons` are requirement **types**, not debug cheats |
| Challenge-mission gate + stage-config switch | ✅ | [challenge-mission-gate](challenge-mission-gate.md) | **`GamePart_ChallengeMission` gates each of the six challenge missions on a CLEARED-STAGE bit**: `REQUIREMENT` absent or `"Always"` → available, else `n = atoi(v)` and it tests bit `n` of singleton `+80` (`n < 24`) or bit `n-24` of `+1956` (`n ≥ 24`) — which is the disc's own stage numbering (story 1–16 and tutorial 18–23 below 24, challenge 24–29 above). Word A's **sole writer** is `0x821C1820` in `GamePart_StageClear`, doing `1 << (this+84)` where `this+84` is the stage number (it also indexes a 20-byte per-stage record array and the debriefing `STAGE` sprite list). So `TimeAttack` needs **stage 16** — the last story mission — and the rest chain off challenge stages 25–29. The six-mission table is on disc in `tables.pak` (schema `54a10697`). Separately, the stage loader picks its config section from a **mission-kind field at `object+144`**: `3` → `EXTRA`, `5`/`6` → `CHALLENGE`, anything else → `FILE`; two further sites treat `{3,5,6}` as one class. Constructed as `0` (`sub_821783D8`) and only ever *cleared* inside the class, so the kind comes from the launching GamePart, **not** from the stage number — which is a mechanism (🟡, unproven) for why patching the save's stage field to a challenge stage kills the load. Same note carries the **GamePart id table** (`0x820A1630`, 29 ids, `GP_CHALLENGE` = 26, cross-checked against the image's own `RegisterToFactory<26, …>` text) and the disc's **three stage families** — `S01`–`S16` story, `S18`–`S23` tutorial, `S24`–`S29` challenge, plus `Test`, matching `weapon.tbl`'s 16 + 6 + 6 key set exactly. `GP_CHALLENGE.pak` holds **0 IDXD objects** — it is the menu screen; challenge missions reuse `GP_MAIN_GAME_E.pak`'s stage records |

## All RE notes (generated)

Every file under `docs/re/`. **Search this table before starting a new
investigation** — the index was previously hand-maintained and listed 20 of 43
files, which is how the same ground got covered twice.

| Note | Title | Status |
|------|-------|--------|
| [`SESSION-2026-08-11.md`](SESSION-2026-08-11.md) | Session log — 2026-08-11 (autonomous run) | — |
| [`arsenal-develop-economy.md`](arsenal-develop-economy.md) | The Arsenal develop economy, and what the save's blob indexes | — |
| [`autopilot-knowledge-sources.md`](autopilot-knowledge-sources.md) | Where the autopilot's missing knowledge lives on the disc |  🟡 this is a map, not the knowledge itself — it says which files |
| [`autopilot-memory-driven.md`](autopilot-memory-driven.md) | Memory-driven autopilot — build log and current state | 🟢 IT FLIES, KILLS AND SURVIVES — but it loses the mission anyway. |
| [`canary-scripted-input-traps.md`](canary-scripted-input-traps.md) | Getting past the title screen in the container — three traps and one blocker |  ✅ CONFIRMED for the three traps (each reproduced, and two of them |
| [`challenge-mission-gate.md`](challenge-mission-gate.md) | Challenge / EX missions — the stage set, the GamePart graph, and the kind field |  ✅ for the static structure (stage set, GamePart ids, the config-section |
| [`dynamic-re-state-restore.md`](dynamic-re-state-restore.md) | The container's dynamic-RE state is not durable — how to rebuild it | ✅ CONFIRMED by rebuilding it (2026-08-23). Everything the dynamic |
| [`flight-controls-runtime.md`](flight-controls-runtime.md) | In-flight control mapping — measured, not assumed |  ✅ for the weapon bindings (ammo counters move), 🟡 for the rest (HUD |
| [`flight-speed-law.md`](flight-speed-law.md) | The throttle is a TARGET-SPEED selector — measured against the definition (2026-08-13) | ✅ for the shape of the law, 🟡 for the unit scale. |
| [`guest-stalls.md`](guest-stalls.md) | The guest stalls, often — and the probe now detects it | ✅ the stall witness works and is validated against independent |
| [`live-unit-definitions.md`](live-unit-definitions.md) | Live unit definitions from a running Stage 02 (2026-08-12) | — |
| [`mission-arrival-watch.md`](mission-arrival-watch.md) | Six runs, no arrival — and an accidental control | ✅ the deployment structure reproduces exactly; ✅ losses require the |
| [`mission-clock-advances.md`](mission-clock-advances.md) | The mission clock is running — the runs were too short in *game* time | 🔴 "the phase clock is stopped" is refuted; ✅ something advances |
| [`mission-escort-state.md`](mission-escort-state.md) | Escort / mission state from guest RAM — every entity's hull |  ✅ CONFIRMED (2026-07-30). Capture: tools/re-capture/mission_state.py, |
| [`mission-freeze-and-ob-flag.md`](mission-freeze-and-ob-flag.md) | An in-mission freeze, and the first cut at what `REMAINING OB` counts | — |
| [`mission-freeze-resume-spin.md`](mission-freeze-resume-spin.md) | The in-mission freeze — the resume-spin lead is DEAD, and the freeze is a guest-side spin | 🔴 the reading this file was named for is REFUTED (2026-08-23, later |
| [`mission-liveness-probe.md`](mission-liveness-probe.md) | A motion-independent live roster — and what `n` probably is | ✅ the enumeration method; ✅ the hunting pilot gets kills; 🔴 "no |
| [`mission-objectives-text.md`](mission-objectives-text.md) | The mission script in plain English — and why phase 1 never completed | ✅ the localised string tables are decoded and readable; ✅ the phase |
| [`mission-outcome-stage02.md`](mission-outcome-stage02.md) | Why Stage 02 is never won — the escort sinks at ~11 minutes (2026-08-10) | ✅ measured, one 500 s run. The standing open item since 2026-07-29 was |
| [`mission-per-record-strength.md`](mission-per-record-strength.md) | Per-record craft strength — the measurement works, the run does not reproduce | ✅ the per-record measurement is internally consistent; 🔴 it does not |
| [`mission-phase-deployment.md`](mission-phase-deployment.md) | Enemies come into play per PHASE, deployed at phase start | 🟡 strongly supported and internally consistent, one unexplained |
| [`mission-phase-objectives.md`](mission-phase-objectives.md) | What each phase asks for — from the game's own objective text | ✅ pinned by a disc test (crates/sylpheed-formats/tests/phase_objectives_disc.rs). |
| [`mission-phase-runtime.md`](mission-phase-runtime.md) | Where the runtime phase state is *not* | ✅ the stage tables are resident in guest RAM, so the static decode |
| [`mission-wave-arrivals.md`](mission-wave-arrivals.md) | The arrival timetable, and what the entity table is really counting | ✅ the static arrival timetable is in Route_S<NN>.tbl; 🟡 the runtime |
| [`movie-subtitle-link.md`](movie-subtitle-link.md) | The movie ↔ subtitle ↔ voice link ✅ (static) | — |
| [`pilot-never-fires.md`](pilot-never-fires.md) | `pilot.py` never pulls the trigger — the proximal cause, measured | ✅ ROOT CAUSE FOUND AND FIXED (2026-08-23, later the same day) — the |
| [`probe-harness.md`](probe-harness.md) | A shared probe harness — so the same lessons stop being re-learned | ✅ built and verified on a live run. |
| [`remaining-ob-hunt.md`](remaining-ob-hunt.md) | Hunting REMAINING OB by correlation — method works, run did not finish | ✅ the correlation method is sound and demonstrated; 🔴 the hunt is |
| [`roster-to-craft-link.md`](roster-to-craft-link.md) | The 116 roster records and the ~300 live craft are not directly linked | 🔴 a direct pointer link is refuted in both directions; ✅ the two |
| [`ship-placement-capture-generalisation.md`](ship-placement-capture-generalisation.md) | Capital-ship placement — does the `e106` result generalise? (WIP, 2026-07-31) |  🚧 WIP, time-boxed session. Two results so far: a static audit across all |
| [`ship-placement-runtime-capture.md`](ship-placement-runtime-capture.md) | Capital-ship part placement — runtime capture (ground truth) |  ✅✅ STATIC ASSEMBLY IS EXACT — no captures needed anymore |
| [`structures/achievements.md`](structures/achievements.md) | Achievements — the 24-entry table, and where the earned state comes from | — |
| [`idxd-legacy-reader-audit.md`](idxd-legacy-reader-audit.md) | The legacy IDXD string-pool reader vs the real field table — what the old numbers got wrong | 🟡 shape CONFIRMED by hand (`FCSRange`, `ShieldRatio`, hangar `Model`); disc-wide rates are single-source |
| [`structures/idxd-container.md`](structures/idxd-container.md) | The IDXD/IXUD container — record/field table, and the two beliefs it withdraws | ✅ CONFIRMED disc-wide, 7 750/7 750 objects and 1 271 462/1 271 462 named fields, zero failures |
| [`structures/hud-glyph-quad.md`](structures/hud-glyph-quad.md) | The HUD's glyph quad — vtable `0x820B2A64` | ✅ CONFIRMED for the object layout and the atlas size, read live off |
| [`structures/mission-objective-counter.md`](structures/mission-objective-counter.md) | `REMAINING OB` — the mission's own objective counter, in RAM |  ✅ CONFIRMED for one Stage 02 run: a big-endian u32 whose value |
| [`structures/movie-subtitles.md`](structures/movie-subtitles.md) | Movie subtitles & the movie ↔ mission ↔ text chain | — |
| [`structures/regn-map-grid.md`](structures/regn-map-grid.md) | `REGN` — a per-map spatial grid (and `MCOL` beside it) | ✅ CONFIRMED for the header, which self-checks on all 11 objects on |
| [`structures/savegame-format.md`](structures/savegame-format.md) | Save file (`savedata`) — container ✅ exact, 3 fields named ✅, rest ❔ (2026-08-11) | ✅ CONFIRMED for the container and the chunk layout — parsed off the |
| [`structures/sound-slb.md`](structures/sound-slb.md) | Sound bank audio — `sound.pak` / `.slb` / XMA1 | — |
| [`structures/stage-definition-table.md`](structures/stage-definition-table.md) | Stage definition table and the squadron (`UnitGroup`) roster | ✅ for the record vocabulary and the stage→table wiring; |
| [`structures/stage-mission-tables.md`](structures/stage-mission-tables.md) | The stage table set — phases, routes, sub-objectives and AI parameters | ✅ the table set and how the stage record reaches it, validated across |
| [`structures/texture-color-k8888.md`](structures/texture-color-k8888.md) | Texture colour interpretation — `k_8_8_8_8` (32bpp UI/HUD textures) | — |
| [`structures/ui-composable-bundles.md`](structures/ui-composable-bundles.md) | A screen build is not the only thing `compose` can draw |  ✅ CONFIRMED by measurement over the disc, with the artifact to |
| [`structures/ui-focus-and-effect-elements.md`](structures/ui-focus-and-effect-elements.md) | `_eff` glow layers are not focused-state records |  ✅ CONFIRMED by measurement over all 965 screen builds on the disc, |
| [`structures/ui-paint-order-key.md`](structures/ui-paint-order-key.md) | The paint order comes from a layer key in the T8aD sprite header |  ✅ CONFIRMED on both screens whose paint order has been measured — |
| [`structures/ui-prm-primitives.md`](structures/ui-prm-primitives.md) | `.prm` elements are untextured full-screen quads, and `kind` bit `0x10` says so |  ✅ CONFIRMED statically across all 965 screen builds on the disc. |
| [`structures/ui-rat-layout.md`](structures/ui-rat-layout.md) | `.rat` — the UI element layout / animation record |  ✅ CONFIRMED for placement (2026-07-28). The retail UI can be |
| [`structures/ui-resting-pose.md`](structures/ui-resting-pose.md) | A keyframe is the start of a ramp, not a pose that is held |  ✅ CONFIRMED against the framebuffer capture of the running title |
| [`structures/ui-screen-runtime.md`](structures/ui-screen-runtime.md) | The UI screen object at runtime — found in live guest memory |  ✅ CONFIRMED for the object's identity and its element array (five |
| [`structures/unit-group-table.md`](structures/unit-group-table.md) | `stage\UnitGroup_S<NN>.tbl` — the per-stage squadron roster | ✅ container format and field semantics, validated across all 28 stage |
| [`structures/unit-struct-runtime.md`](structures/unit-struct-runtime.md) | Runtime `Unit` struct (craft / vessel definitions) — read from live guest memory | — |
| [`structures/weapon-struct-runtime.md`](structures/weapon-struct-runtime.md) | Runtime `Weapon` / `Shell` structs — read from live guest memory | — |
| [`structures/xbg7-mesh.md`](structures/xbg7-mesh.md) | XBG7 — mesh geometry (inside XPR2 model containers) | — |
| [`title-crash-stl-tree.md`](title-crash-stl-tree.md) | The title-screen crash is an STL `map`/`set` erase on a bad iterator |  ✅ CONFIRMED — the guest throws std::out_of_range from an STL |
| [`ui-paint-order-third-permutation.md`](ui-paint-order-third-permutation.md) | A third measured paint order — tool built and validated, screen not reached |  ✅ the reader works and is CONFIRMED against both previously |
| [`ui-quad-class-foothold.md`](ui-quad-class-foothold.md) | The guest's UI quad class — a foothold found from the capture's vertex layout |  🟡 PROBABLE for the identification below (it is a static read, but |
| [`ui-title-paint-order-capture.md`](ui-title-paint-order-capture.md) | The title screen's paint order, measured from the guest's draw submissions |  ✅ CONFIRMED — the order in which the running game paints the title |
| [`upstream-baseline.md`](upstream-baseline.md) | A stock-upstream baseline runs Stage 02 crash-free |  ✅ CONFIRMED — upstream canary_experimental + only the pad |
| [`weapon-datasheet-runtime.md`](weapon-datasheet-runtime.md) | Weapon DATA SHEET — runtime capture (Route B) |  🟡 first dynamic capture, 2026-07-28. The Arsenal's Gallery Mode panel is a |
| [`xpr2-colour-check.md`](xpr2-colour-check.md) | XPR2 colours: channel order ✅ confirmed against the running game | — |