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disasm/_wip/Pac-Man (U)/OVERVIEW.md
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tmerritt 9aef410424 Promotes Donkey Kong Jr
Adds remaining NROM as _wip
Update gitignore to not keep object files
Adds AGENTS.md as this is an AI helped project
2026-10-16 13:46:20 -04:00

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Pac-Man (U) — Skeleton Project

ROM: _wip/Pac-Man (U)/Pac-Man (U) [!].nes (24,592 bytes, iNES). Status: SKELETON — not yet disassembled. The entire 16 KB PRG bank is a single unclassified block; copilot/prg.s is the default-project skeleton (default_project.tar.gz) that reproduces it as one .incbin. The skeleton build is byte-identical at the PRG level.

Variant note: Pac-Man (Tengen) (U) is an unrelated dump (different PRG). Both use vertical mirroring.

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 Vertical
Battery-backed flag clear
ROM SHA-256 d5e9c4e81ff7316d4d8b15f2198471606fdb728b8cd9da92b153bdc45124b565
PRG SHA-256 c1b777982f55de192c9f8cd9738445d3704d5c3b31ba01647a1609aad6c2872e

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

Vector Target Note
NMI $C0FA per-frame heartbeat
RESET $FF00 initial execution at $FF00, inside the last PRG page — unusual; PASS 1 should confirm the true cold-start path
IRQ $C16A target $C16A — verify during Pass 1

copilot/ Contents

File Purpose
Pac-Man (U) [!].nes original ROM image (reference)
prg.bin / header.bin / chr.bin split image, produced by _tools/splitnes.py
prg.s Pass-1 skeleton: .incbin "prg.bin", $0000, $4000 (whole PRG)
symbols.inc shared NES hardware constants (PPU/APU/controller, from the skeleton)
locals.inc project-local zero-page aliases — empty for now (filled in Pass 2)
linker.cfg PRG at $C000, 16 KB, fill = yes
Makefile links reconstructed_prg.bin and cmps 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, which is exactly what a skeleton proves. 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

cd "_wip/Pac-Man (U)/copilot"
make        # → cmp reconstructed_prg.bin prg.bin → "BYTE-IDENTICAL"

Next Steps (per PROMPTS.md)

  1. Pass 1 — replace the blanket .incbin with classified code/data: trace reachability from RESET ($FF00) and NMI ($C0FA), emit per-instruction ; PRG:$xxxx AA BB annotations, keep unreached bytes as explicit .byte blocks.
  2. Pass 2 — replace Label_/Sub_ names with semantic routine names; fill locals.inc.
  3. Pass 3 — name data tables/structures; release provisional flags.
  4. 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.