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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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CIRCUS — Skeleton Project

ROM: _wip/CIRCUS/CIRCUS.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.

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	`608a8c542e49d5fa500634aa49ee96921d52c49c6e1646db7ca21ac7682ce4ba`
PRG SHA-256	`e707fddce05efeb064b644b91b36969e4f4d7723db9965a1a1a85021a6a3da57`

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

Vector	Target	Note
NMI	`$C05A`	per-frame heartbeat
RESET	`$C000`	cold start at $C000 — the usual pattern in this repo
IRQ	`$4CB7`	$4CB7 is outside the mapped address space — effectively unused

`copilot/` Contents

File	Purpose
`CIRCUS.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 `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, 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/CIRCUS/copilot"
make        # → cmp reconstructed_prg.bin prg.bin → "BYTE-IDENTICAL"

Next Steps (per `PROMPTS.md`)

Pass 1 — replace the blanket .incbin with classified code/data: trace reachability from RESET ($C000) and NMI ($C05A), emit per-instruction ; PRG:$xxxx AA BB annotations, keep unreached bytes as explicit .byte blocks.
Pass 2 — replace Label_/Sub_ names with semantic routine names; fill locals.inc.
Pass 3 — name data tables/structures; release provisional flags.
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.

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