# Mechanics reconstruction progress

This ledger scopes the current reverse-engineering pass to the claw and
flippers. The preserved executable is the authority; `TDKPIN_GHIDRA_RAW.c`
remains immutable raw evidence, while `TDKPIN_MECHANICS_RESTORED.c` carries
reviewed names and control flow.

Target: `TDKPIN.EXE` SHA-256
`a9022f1894e3e6e21fc42e8f6c932f7c549ca77f63aaa0c488bb9d55d9d0174c`.

## Function inventory

| Address | Raw name | Restored role | Status |
| --- | --- | --- | --- |
| `1000:638e` | `FUN_1000_638e` | key-release flag updates | reviewed |
| `1000:6bf8` | `FUN_1000_6bf8` | key-press flag updates | reviewed |
| `1000:7ed9` | `FUN_1000_7ed9` | flipper collision movement and sound | reviewed; inner fixed-point geometry still raw |
| `1000:8b0d` | `FUN_1000_8b0d` | flipper bitmap/collider movement | reviewed; inner fixed-point geometry still raw |
| `1000:99f0` | `FUN_1000_99f0` | binary flipper transition state machine | restored |
| `1000:c79c` | `FUN_1000_c79c` | collision dispatch, including claw object `0x59` | claw branch restored |
| `1000:eab1` | exported ordinal 10 | timer tick, claw release and return | claw branch restored |
| `1008:0002` | `FUN_1008_0002` | sound-enabled dispatch | restored |
| `1008:0e08` | `FUN_1008_0e08` | claw background restore and sprite slicing | restored |

Inventory coverage is 9/9 functions inspected for this mechanism pass. This is
not a claim that all instructions in the two large physics functions have been
renamed.

## Proven behavior now available to the Rust port

- Left Control (scan `0x1d`) and keypad Enter (scan `0x1c`) set input flags;
  the timer changes each flipper position only between 0 and 1.
- Every flipper movement edge, including return, invokes sound number 21,
  Win16 WAVE resource 2021.
- Claw collision object `0x59` suspends the ball, zeros its live motion,
  disables collision records 12 through 20, and selects terminal frame 1, 6,
  7, or 18.
- The claw advances exactly one frame per timer tick to its terminal, releases
  the ball, then advances one frame per tick back to frame 10 before clearing
  the overlay and restoring collision records 12 through 20.
- Resource 900 is sliced into 100x74 frames, nine columns by four rows. The
  destination is `(238,47)`; closing rows begin at source y=0 and opening rows
  at source y=148.
- Claw capture/contact uses sound 2015; release uses sound 2016.

## Explicit pending evidence

- Decode the runtime/FPU conversion used to project the claw's raw 16.16
  release coordinates and non-frame-18 velocity into playfield pixels.
- Recover or differentially measure the timer cadence used for each claw frame.
- Transcribe the full fixed-point flipper impulse calculation, then compare it
  with the Rust floating-point collision response.
- Validate the reconstructed sequences against deterministic Rust traces and
  captured frames from the original executable.

Those four items are intentionally not counted as semantic parity. The readable
C file preserves their raw constants and labels the unresolved conversion so a
later implementation cannot silently turn an estimate into claimed evidence.