# Pinball (JU) — Pass 2 Complete

ROM: `_wip/Pinball (JU)/Pinball (JU).nes` (24,592 bytes, iNES). Status: **Pass 2 complete — semantic labels and zero-page names applied, PRG byte-identical.** `copilot/prg.s` now contains a classified disassembly with 4,734 instructions (59.5% code), 196 semantic labels, and 150 zero-page semantic aliases. The build is **BYTE-IDENTICAL** at the PRG level.


## ROM Facts

| Property | Value |
|----------|-------|
| Mapper | 0 (NROM) — from the iNES header |
| PRG | 16 KB (header claims map at CPU $C000–$FFFF) |
| CHR | 8 KB |
| Mirroring | Horizontal |
| Battery-backed flag | clear |
| ROM SHA-256 | `451a201c067bbabad8d762c3fdc2a83cb0b93f26ed0c350cf23bbf486f7addb6` |
| PRG SHA-256 | `1d79f41ef62d5045db2c45c9c75766d54c0a84e167d8067bbb6fb90227ac5619` |

## Interrupt Vectors (taken from PRG $3FFA–$3FFF)

| Vector | Target | Note |
|--------|--------|------|
| NMI | `$C1ED` | per-frame heartbeat |
| RESET | `$C000` | cold start at $C000 — the usual pattern in this repo |
| IRQ | `$C1ED` | target $C1ED — verify during Pass 1 |

## `copilot/` Contents

| File | Purpose |
|------|---------|
| `Pinball (JU).nes` | original ROM image (reference) |
| `prg.bin` / `header.bin` / `chr.bin` | split image, produced by `_tools/splitnes.py` |
| `prg.s` | Pass 1/2: classified code/data split, 4,734 instructions, 196 labels, audit comments on every emission |
| `symbols.inc` | shared NES hardware constants (PPU/APU/controller, from the skeleton) |
| `locals.inc` | 150 zero-page semantic aliases (filled in by Pass 2) |
| `linker.cfg` | PRG at $C000, 16 KB, `fill = yes` |
| `Makefile` | links `reconstructed_prg.bin` and `cmp`s it against `prg.bin` |
| `reconstructed_prg.bin` | build output from the last verified build |

Header/CHR are reproduced verbatim from `header.bin`/`chr.bin` (not linked): `make` verifies **PRG bytes only** at this stage. When this project is promoted to a full disassembly, `header.s` / `chr.s` (as e.g. `Burger Time (U)`) and a full-ROM `make` target get added.

## Build

```bash
cd "_wip/Pinball (JU)/copilot"
make        # → cmp reconstructed_prg.bin prg.bin → "BYTE-IDENTICAL"
```

## Next Steps (per `PROMPTS.md`)

1. **Pass 3** — name data tables/structures; release provisional flags.
2. **Promotion** — move to a top-level `<name>/copilot/` folder, add full-ROM build (header.s + chr.s + vectors), and write the power-on flow `OVERVIEW.md` in the established style; then it joins the root index's numbered inventory.

## Pass 2 Details (2026-10-18)

- **Label renaming**: 196 of 681 labels renamed to semantic names using `pass2.py apply` with a mapping file (`pinball_label_map.tsv` + `pinball_zp_map.tsv`). Key renamed routines:
  - RESET/NMI: `Reset`, `NmiHandler`
  - System init: `InitSystem`, `ClearZeropage`, `InitGameState`
  - Main loop: `MainGameLoop`, `GameModeTitle`, `GameModePlay`, `WaitVBlankFrame`
  - NMI: `NmiHandler`, `NmiFrameEnd`
  - Ball physics: `BallPhysics`, `CheckTilt`, `CheckBallInPocket`
  - Flipper logic: `UpdateFlipper`, `UpdateFlipperSprites`, `UpdateFlipperSound`
  - Ball physics: `BallPhysics`, `UpdateBallPosition`, `UpdateBallVelocity`, `UpdateBallTrajectory`
  - Collision: `CheckCollision`, `CheckFlipperHit`, `CheckBallInPocket`
  - Scoring: `UpdateScore`, `UpdateScoreDisplay`, `DrawScore`, `DrawDigits`
  - Sound: `InitSound`, `PlaySound`, `UpdateMusic`
  - PPU: `WaitVBlank`, `WaitPPUReady`, `WritePPU`, `DrawSprite`
  - Sound engine: `UpdateSoundEngine`, `UpdateSoundChannel` (1-35)
- **Zero-page semantic aliases**: 150 aliases in `locals.inc` (e.g., `FrameCounter`=$02, `GameState`=$03, `PlayerLives`=$04, `BallX`=$24, `BallY`=$25, `BallVelX`=$26, `BallVelY`=$27, `FlipperLeft`=$28, `FlipperRight`=$29, `SpriteIndex`=$95, etc.)