ddidderr
75c2464e72
Correct the coordinate model from guessed 16.16 values to the millipixel arithmetic shown by the 16-bit division routine. Decode the Borland Real48 direction constants and record the exact position and velocity tables used by every claw terminal. Test Plan: - git diff --cached --check - Compare constants against segment 1 disassembly at 9bca and eab1
64 lines
3.4 KiB
Markdown
64 lines
3.4 KiB
Markdown
# Mechanics reconstruction progress
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This ledger scopes the current reverse-engineering pass to the claw and
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flippers. The preserved executable is the authority; `TDKPIN_GHIDRA_RAW.c`
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remains immutable raw evidence, while `TDKPIN_MECHANICS_RESTORED.c` carries
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reviewed names and control flow.
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Target: `TDKPIN.EXE` SHA-256
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`a9022f1894e3e6e21fc42e8f6c932f7c549ca77f63aaa0c488bb9d55d9d0174c`.
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## Function inventory
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| Address | Raw name | Restored role | Status |
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| --- | --- | --- | --- |
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| `1000:638e` | `FUN_1000_638e` | key-release flag updates | reviewed |
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| `1000:6bf8` | `FUN_1000_6bf8` | key-press flag updates | reviewed |
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| `1000:7ed9` | `FUN_1000_7ed9` | flipper collision movement and sound | reviewed; inner fixed-point geometry still raw |
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| `1000:8b0d` | `FUN_1000_8b0d` | flipper bitmap/collider movement | reviewed; inner fixed-point geometry still raw |
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| `1000:99f0` | `FUN_1000_99f0` | binary flipper transition state machine | restored |
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| `1000:c79c` | `FUN_1000_c79c` | collision dispatch, including claw object `0x59` | claw branch restored |
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| `1000:eab1` | exported ordinal 10 | timer tick, claw release and return | claw branch restored |
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| `1008:0002` | `FUN_1008_0002` | sound-enabled dispatch | restored |
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| `1008:0e08` | `FUN_1008_0e08` | claw background restore and sprite slicing | restored |
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Inventory coverage is 9/9 functions inspected for this mechanism pass. This is
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not a claim that all instructions in the two large physics functions have been
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renamed.
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## Proven behavior now available to the Rust port
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- Left Control (scan `0x1d`) and keypad Enter (scan `0x1c`) set input flags;
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the timer changes each flipper position only between 0 and 1.
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- Every flipper movement edge, including return, invokes sound number 21,
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Win16 WAVE resource 2021.
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- Claw collision object `0x59` suspends the ball, zeros its live motion,
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disables collision records 12 through 20, and selects terminal frame 1, 6,
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7, or 18.
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- The claw advances exactly one frame per timer tick to its terminal, releases
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the ball, then advances one frame per tick back to frame 10 before clearing
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the overlay and restoring collision records 12 through 20.
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- Resource 900 is sliced into 100x74 frames, nine columns by four rows. The
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destination is `(238,47)`; closing rows begin at source y=0 and opening rows
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at source y=148.
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- Claw capture/contact uses sound 2015; release uses sound 2016.
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- The release-coordinate projection is `(raw + 500) / 1000` for rendering;
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decoded physics centers are `(258,78)`, `(270,94)`, `(275,97)`, and
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`(325,92)` for the four selectable terminal frames.
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- The speed scalar is 3800 millipixels per tick. Its Borland Real48 direction
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constants are decoded for all release cases in the readable C companion.
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## Explicit pending evidence
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- Differentially verify the recovered 10/20/30/40/50 ms timer choices against
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live original captures; the Rust port intentionally uses the default 30 ms
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claw cadence independently of render rate.
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- Transcribe the full fixed-point flipper impulse calculation, then compare it
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with the Rust floating-point collision response.
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- Validate the reconstructed sequences against deterministic Rust traces and
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captured frames from the original executable.
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Those items are intentionally not counted as semantic parity. The readable
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C file preserves their raw constants and labels the unresolved conversion so a
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later implementation cannot silently turn an estimate into claimed evidence.
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