ecf6887b76
stage\UnitGroup_S<NN>.tbl is now fully readable. A squadron record is Count
member tuples -- (unit model, message set, n, identity/nameplate) -- followed by
five named fields: Count, SideID, AIID, FormationID, DisableInterval. The
property entries carry their own field names inline, so the tag hash never has
to be inverted.
Two independent self-checks validate it corpus-wide, 1160/1160 each across all
28 stage tables on the disc:
- the length identity len(fields) == Count * 4 + 5, which is what pins the
member-tuple width at 4 and the named-field count at 5;
- agreement with the file's own Enumerate_Squadrons roster, which maps record
key to squadron id independently of the per-record string offset.
Adds tools/re-capture/unitgroup.py (pure static, runs no emulator) with a
--all --check self-check mode, and commits the Stage 02 dump as evidence.
Corrections to the container layout written yesterday, all three wrong:
- the 20-byte "(tag, 0, 0, count, size) section header" does not exist. It
was the file's last 16-byte record followed by a plain npool word. The
corrected layout is uniform across all 28 files; the old one failed on 9.
- squadron ids do not use a separate string base. Every offset in the file is
relative to the one string pool. The earlier "109 of 111" score was an
artefact of the uniform 7-byte id stride and had silently shifted every
name by three entries, which is why 17 TC*-named squadrons came out as
SideID=ADAN. The roster record refuted it outright.
- the roster is not always the last record; 9 stages put it elsewhere, so it
is found by its missing Count.
Refuted and kept: the 4-byte record key is not the squadron id's name hash
(0 of 112).
Not settled: what the key encodes, the member tuple's third field n, and where
the arrival interval values live. DisableInterval is only a per-squadron flag
(Yes for 31 of 1160); the durations, triggers and arrival positions are not in
this file. Formation_*.tbl and EnumSquadron_Test.tbl are next.
Reverse-engineering knowledge base
This directory is the spec-side of the clean-room: it records what the original Project Sylpheed binary does (behaviour) and how its data is laid out, so that the Rust port can be implemented from these specs without re-deriving anything and without ever copying original code.
It exists to answer one question fast: "do we already know how X works, and how sure are we?"
The one rule that matters
Never document a claim more confidently than the evidence supports, and never paste original code here.
A wrong-but-confident note is worse than no note: someone builds on it and the bug hides for weeks. Every entry therefore carries an explicit confidence and its evidence. This mirrors the project method — measure the oracle, never infer; refute before believing.
Clean-room firewall
- ✅ Allowed: behaviour descriptions, field offsets/types, formulas, state machines,
observed input→output pairs, and references to the original by address
(
sub_821B68C0) or toxenia-rs/sylpheed.db. - ❌ Forbidden here and in
crates/: pasted decompiled C/C++ or verbatim disassembled function bodies presented as the thing to reimplement. Cite the address; describe the behaviour in your own words. Disassembly is a tool for understanding, not a source to copy.
Confidence levels
| Level | Meaning | Bar to reach it |
|---|---|---|
CONFIRMED |
Behaviour verified against ground truth. | ≥2 independent observations or one observation cross-checked against an oracle (canary framebuffer, a known-correct value, a second code path). |
PROBABLE |
Strong single-source inference. | One clean observation, or an unambiguous static read of the disassembly. |
HYPOTHESIS |
Educated guess, not yet tested. | Anything else. Must say what would confirm/refute it. |
Promotion requires new evidence, not re-reading the old evidence. A HYPOTHESIS that
"looks right again" is still a HYPOTHESIS. Only an independent check promotes it.
If evidence later contradicts an entry, demote it and record the contradiction — do
not silently edit the conclusion.
When to document
- Right after a function/structure crosses from
HYPOTHESISto at leastPROBABLE— before moving to the next code path, so the knowledge isn't lost or re-derived. - Whenever confidence changes (up or down) — append to the Evidence log, don't overwrite.
- Not while it's still a pure guess with no evidence — a one-liner in the relevant backlog/plan is enough until there's something to stand on.
What to document
- Functions/code paths →
docs/re/functions/<name>.md(one file per function or tight cluster). - Data structures / formats →
docs/re/structures/<name>.md. - Keep the index in
INDEX.md(one line each: name · confidence · one-line summary).
Use the templates: _TEMPLATE.function.md,
_TEMPLATE.structure.md.
How we find and confirm code paths (the toolchain)
Everything joins on the guest virtual address (PC) — code addresses are fixed by the XEX load, identical across our emulator and canary.
- Static (cheap, try first):
xenia-rs/sylpheed.db(DuckDB: 25 481 functions, xrefs, strings, vtables, imports). Query withxenia-rs/zq.py—zq.py grep <str>,zq.py xref <addr>,zq.py dis <lo> <hi>,zq.py fn <pc>. Entry points are usually a string (zq.py grep MSG_DEMO) or an import (movie/XMA API) xref'd back to the loader. - Dynamic (when static is ambiguous): run
xenia-rswith its probe suite —--pc-probe/--audit-pc-probe-hex(fires at block entry),--mem-watch(mid-block reads/writes of a VA),--lr-trace(call/return chains),--trace-instructions,--dump-addr(read guest memory). These already exist; prefer them over hacking canary. - Oracle (correctness ground truth): canary — the Wine cross-build
xenia-canary/build-cross/bin/Windows/Debug/xenia_canary.exe(the native Linux ELF crashes / does not run — do not use it). This is the only emulator that reaches the in-game menu; ourxenia-rsnever got past the intro video. Use canary to observe output (capture its framebuffer for texture colours), not usually to instrument code — though itsbuild-crosstoolchain does compile, so small C++ probes + rebuild are possible when needed. Run muted, one emulator process at a time, point it at the real ISO (not the symlink).
⚠️ VA-equality caveat: join code by PC (fixed), but never assume a data VA holds the same bytes across emulators — allocators differ. Compare data by content/layout.