sylph-decoder 7e20b4b3b8 re: the decoder's timers are a double-tap latch on LB/LT, not key repeat
Answers H1's first half with a negative, and decodes what the timing
constants are for.

C_PAD_DECODER's +0xB4/+0xB8 and +0xBC/+0xC0 (10 and 90, twice) are not a
key-repeat delay/interval pair. They are two identical channels of a
DOUBLE-TAP detector, on cfg +0x74 (LT) and +0x70 (LB), firing output bits
0x20 and 0x40.

The mechanism, from the image: both timers tick down once per update; a
press arms the short timer to 10; a RELEASE adds 1000 to it as a flag
stored inside the counter, which is why the tick watches for exactly 1000
and clears both there; a second press while the flag is set arms the long
timer to 90; and while the long timer runs the output bit is asserted on
EVERY update, with the short timer re-armed to 1010 each time.

So it is a latch, not a repeat: a double-tap opens a 90-update window and
the bit is held for its whole duration. That is a dash or barrel-roll
shape, which fits the buttons it is wired to.

H1: the directions have NO timer. The D-pad and left stick reach the output
word through bare mask tests -- the four left-stick literals at 0x8220C458,
C474, C490, C4AC, and DPAD DOWN through cfg +0xA4 -- with no counter
loaded, decremented or tested on any of those paths. On the evidence of
this layer a held direction does not repeat.

Reach: one layer. A menu could implement repeat on top of a held bit, and
this says nothing about that -- but it does establish the repeat is not in
the shared decoder, so it would have to be per-screen. "One step per
deflection" stays authored for the port; this narrows rather than settles.

Refutation of my own earlier note that a decoder "is where a game normally
puts its repeat timing, its edge detection and its button remap": remap
survives, edge detection survives, repeat timing is REFUTED. That clause
was a prior about how games are written, not a reading of this one.

Also commits tools/ppc-dis, the minimal PowerPC disassembler this corpus
has been rebuilding in scratch and losing to container restarts three times
in one session.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Jc4pciRArGHfxGGhEbwp5t
2026-09-02 16:20:50 +00:00

Sylpheed

A clean-room reverse engineering and port project for Project Sylpheed: Arc of Deception (Xbox 360, 2007).

Three things live here, in one repository so that a change spanning them lands as one commit:

The decoders crates/sylpheed-formats — the disc's formats, read and verified disc-wide
The port port/ — a Godot 4 project, plus crates/sylpheed-export which converts a disc into the open asset tree it reads
The corpus docs/re/ — what has been reverse engineered, with its evidence, its retractions and its dead ends

You need your own copy of the game. No game content is in this repository and none ever will be. The exporter reads the disc you supply.

The oracle is the real game

sylpheed-cli and the Explorer are tools for verifying our decoding. They are hypotheses under test and they have been wrong. When something must be checked against the truth, the truth is the game running in Xenia Canary, captured — not any renderer of ours.

This is stated first because getting it backwards is the most expensive mistake this project has made.

Layout

crates/
  sylpheed-formats/   the decoders. Disc-wide verified; the corpus is its spec
  sylpheed-cli/       headless tools -- render a screen, dump a table, probe audio
  sylpheed-viewer/    the Explorer: a human's window onto the disc. STATIC data only
  sylpheed-export/    disc -> the open, moddable asset tree
port/                 the Godot 4 project. Reads open formats ONLY
authored/             decisions that are NOT on the disc, each with its reason
data/
  base/               generated by the exporter. Gitignored, never hand-edited
  mods/               drop-in overrides. Yours
docs/
  re/                 the corpus: findings, refutations, method traps
  game/               how the game is navigated -- menus, modals, flight
  port/               the port's mission, its handoff contract, modding rules
  agents/             how the agent team works together
tools/                capture harnesses, probes, the share tool
exchange/             transient inter-agent files. NOT in git
docker/               the agent containers

Where to start

Xenia Canary is a separate repository: it is a fork tracking upstream, and it carries our instrumentation.

Conventions

Confidence is per claim, never per document: CONFIRMED · 🟡 PROBABLE · HYPOTHESIS · REFUTED. A withdrawn result is kept with its reasoning rather than deleted — that is why the numbers here can be trusted.

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