Files
Sylpheed/docs/re
Sylpheed RE agent b0fc1e6e7b re: kill run -- arrival timing reproduced (n=2), decrement inconclusive, "live attackers" refuted
pilot.py with SYLPH_PREFER=e010, 300s, mission clock sampled throughout.

RISES REPRODUCED: 004 -> 008 in (114.8s, 134.7s] and 008 -> 012 in (196.4s,
213.3s], both brackets containing the predicted 120 and 210.  Second independent
run, so the arrival half is now n=2.

DECREMENT INCONCLUSIVE.  The pilot fought properly -- 424 fire=1 samples, 865 with
the target inside 1500 units, closest approach 79, target e010 throughout, hull
untouched -- and 13 ADAN died (129 -> 116).  The counter held 012 for 98s.  That is
NOT evidence against the decrement: the 13 dead were not identified by class, this
pilot's kills historically skew to turrets, and the live e010 count ROSE over the
run so attacker deaths cannot be inferred from it.  Recording it as inconclusive
rather than as a negative, which is the error this corpus has already logged twice.

POSITIVE RESULT: at TIME 05:56.85, both arms sampled together, REMAINING OB = 012
while live UN_e010_ADAN_Attacker_S = 23.  So the counter is NOT the live attacker
head-count; it tracks a subset, and 12 is exactly the three A-route squadrons'
membership (3 x n=4).  Phase 1 fields only 16 e010, so 23 live means later-phase or
F-route squadrons joined without touching the counter.

Anomaly recorded, not explained: the enumeration reports 2 _Player entities at two
distinct positions.
2026-08-27 02:18:29 +00:00
..

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 to xenia-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.

The status markers

The table above is the confidence scale. The markers that appear in BACKLOG.md and the structures/ pages are a separate, and until now undefined, vocabulary. They mean:

Marker Meaning
Confirmed — verified against ground truth.
🟡 Partial: true as far as it goes, or true under a stated assumption.
Open question. Nobody has answered it yet.
🔴 Refuted — shown false — or blocked by something the container cannot do.
A specific claim that was tried and failed. Prefer 🔴.
🚧 Work started and not finished.

🔴 never means "we have not run it yet." That is or 🚧. Reserve 🔴's "blocked" sense for a real limit of the box — no push credentials, no hardware Vulkan (lavapipe only), or a decision only the user can make. The box can run the emulator, script input, screenshot, read guest memory, and build and test Rust, so "needs a run" is never a blocker. This paragraph exists because the marker was undefined for 98 uses and three of them were mislabelled that way.

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 HYPOTHESIS to at least PROBABLE — 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 pathsdocs/re/functions/<name>.md (one file per function or tight cluster).
  • Data structures / formatsdocs/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 with xenia-rs/zq.pyzq.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-rs with 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; our xenia-rs never got past the intro video. Use canary to observe output (capture its framebuffer for texture colours), not usually to instrument code — though its build-cross toolchain 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.