# TODO / Handoff Written so a fresh session can pick this up cold. Everything below was verified against the repo at commit `9e2b50a`; if a number here disagrees with the repo, the repo is right and this file is stale. > **Note:** This file documents work completed up to 2026-10-20 (promotion of Ice Climber, > Lode Runner and Pinball; `_wip` evaluation). The actual repo state is always the source of truth. > > **Layout note (2026-10-20):** projects now live under their **mapper directory** > (`NROM/`, `AOROM/`, `CNROM/`, `MMC1/`, `MMC3/`, `MMC5/`, `UNROM/`), project folders > are **flat** (the `copilot/` subfolder is gone — strip the prefix when reading older > references below), every project's `OVERVIEW.md` is now its `README.md`, and a root > `Makefile` builds, verifies and cleans every project (`make`, `make clean`, > `make `); the pre-commit hook drives it. Both tiers sit two levels deep, so > `../../_tools/` is correct from any project folder. ## The contract Byte-identical rebuild is the hard requirement. In every project folder: ```bash make # must print "Byte-identical ROM verified." ``` A build that assembles but does not print that message is a failure. Requires `ca65`/`ld65` on PATH. Never edit bytes to make a build pass — fix the source. Two tiers exist, and the difference is real: - **Top level — promoted projects under their mapper dir (`NROM/` etc.) — `make` compares the whole ROM against `rom.nes` in the project folder. - **`_wip//` (857 projects)** — as of 2026-10-20 these also compare the whole ROM against a `rom.nes` copy in the project folder, so the header and CHR **are** proven. The tier was moved off the old `cmp reconstructed_prg.bin prg.bin` form; promotion is now `git mv` plus the disassembly work, with no build surgery. See **`WIP.md`** for the tier's layout, its quirks and its open work. Promotion still requires what promotion always required: a real disassembly (Pass 1 or beyond) with the canonical audit comments, and the Pass 2/3 naming work. ## Current state - 35 promoted projects under `NROM/`, all whole-ROM byte-identical (Lunar Pool promoted 2026-10-18, Donkey Kong (JU) promoted 2026-10-19 after Pass 3, **Donkey Kong Jr. Math (U) promoted 2026-10-19 after Pass 3 — re-promoted into `NROM/` 2026-10-20** after the 2026-10-20 mapper-folder reorganization initially parked it in `_wip/NROM/` over a `jsr $F218`-mislabeled-as-`SubCF218_Block` mismatch; the fix repointed four `prg.s` call sites to the true `SubCF218` entry, see `NROM/Donkey Kong Jr. Math (U)/README.md`), **Duck Hunt (JUE) promoted 2026-10-19 after Pass 3**, **Ice Climber (JE) and (U) promoted 2026-10-20 after Pass 3**, **Lode Runner (U) promoted 2026-10-20 after Pass 2/3**, **Pinball (JU) promoted 2026-10-20 after Pass 2/3**, **Popeye (JU) (PRG 1) promoted 2026-10-20 after Pass 2/3** (`header.s`/`chr.s` + HEADER `linker.cfg` added, whole-ROM `cmp` passes on the first promoted build; SHA-256 `00160651…78bd8b4`; see `NROM/Popeye (JU) (PRG 1)/README.md`), **`Excitebike (JU)` promoted 2026-10-20** — the byte-596 mismatch was two `PpuMaskShadow` (`$0A`) operands where the ROM uses `$11` (NMI's second mask shadow, aliased as `NmiMaskShadow` in `locals.inc`); the 4,401 damaged audit comments (doubled `??` forms plus 6,339 comments shifted against their mnemonics) were re-anchored from the ca65 listing via the new `_tools/repair_audit_comments.py`, and all 58 raw `jsr/jmp $XXXX` operands were substituted with routine labels/equates. See `NROM/Excitebike (JU)/README.md`. **`Raid on Bungeling Bay (U)` promoted 2026-10-20** — `header.s`/`chr.s` + HEADER/PRG/CHR `linker.cfg` added, whole-ROM `cmp` passes on the first promoted build (MD5 `77285503…885000ac`); one leftover neutral indirect operand `jmp (Zp01)` at $E2EC became `jmp (IndDispatch01)` (alias already present in `locals.inc`); `apply_symbols.py` reports 0 substitutions pending. **`Pac-Man (U)` promoted 2026-10-20** — Pass 2 completed first (all 194 `Label_XXXX` definitions renamed from a fresh map derived from the committed split, not from a drafted map; all 49 `jsr`/`jmp` call sites resolved; zero `Label_` and zero raw `$XXXX` call operands left), then Pass 3: **119 operands substituted** (101 hardware + 11 single-name + 7 multi-alias resolved per site through a new `sites.tsv`), `apply_symbols.py` now reports **0 residue**. The 7 site resolutions are all proven from context, not guessed — four `jmp ($0010)` immediately preceded by `sta DispatchPtrLo`/`sta DispatchPtrHi`, one `jmp ($00FE)` preceded by `sta AudioHandlerPtrLo`/`sta AudioHandlerPtrHi`, and two `sta a:$0000,y` zero-page clears that take the neutral `Zp00`. `header.s`/`chr.s` + HEADER/PRG/CHR `linker.cfg` added, whole-ROM `cmp` passes on the first promoted build (MD5 `a69d310f8cae9397fbd39f204672b5c7`); see `NROM/Pac-Man (U)/README.md`. **`Pac-Man (Tengen) (U)` promoted 2026-10-20** — a *different build* of the same game as the row-32 dump: the PRGs differ in 56 bytes in 8 runs, all of them code-versus-licensee-text ($C3E3-$C408 is 26 spaces here against `LICENSED BY NAMCO AMERICA INC` there; $FF00-$FF16 is `$FF` padding here against the boot code there), and the RESET vector follows ($C033 against $FF00) — the same boot sequence, inline. Disassembled **from scratch**: the map was derived from this dump's own committed split, with no name, map or file carried over from the row-32 dump. Pass 2 named all 194 `Label_XXXX` definitions and resolved all 48 raw `$XXXX` call operands (map in `routinemap.tsv`); Pass 3 added 30 semantic zero-page aliases applied only at the proven sites (`sites.tsv`) and named 28 data tables, including `CharacterDataTable` ($C66A) / `CharacterNameStrings` ($C67E), where the ROM itself names Blinky, Pinky, Inky and Clyde. **A Pass 1 correction came with it:** six command handlers were recovered — `ScriptCommandTable` ($EFDD) is read by the traced instruction at $EFCC and six of its entries point at $F00A, $F022, $F03A, $F052, $F062 and $F072, all of which the tracer had left as data, two of them mis-split across the `jmp $EF61` at $F01F and $F04F. Those 120 bytes are code here. **The same gap exists in the promoted row-32 dump, which has not been corrected.** `header.s`/`chr.s` + HEADER/PRG/CHR `linker.cfg` added, whole-ROM `cmp` passes on the first promoted build (MD5 `d34e7a74…28ad0`); see `NROM/Pac-Man (Tengen) (U)/README.md`. ****`Pyramid (U)` (Sachen) promoted 2026-10-20** — an unlicensed Sachen release with a mapper-0 header whose boot code pokes a mapper unlock at `$4100` and checks the RAM bytes `$0120`/`$0121` against "A"/"V". **A Pass 1 correction came with it:** the committed split was a strict subset of the correct one — **828 bytes** of code were still marked as data, because the tracer cannot follow a `jmp` that sits inside a data region, and this game dispatches through four such tables ($C01E, $C02A, $C042, $C054) plus ten more at $C000-$C01B. Re-tracing with those sixteen targets, the `$C800` boot mainline and six further code starts seeded by hand recovers them (and a five-byte stub at $DF89 in a hole between two routines); the re-trace loses **no** committed code byte and takes the split from 34.5% to 39.6%. `make regen` reproduces it, so the split stays verifiable. Pass 2 named 431 routine entries and the 32 data blocks from this dump's own code (428 `Label_XXXX` gone, 320 raw `$XXXX` call operands resolved; the internal branch-target names are derived mechanically by the new `_tools/derive_branch_names.py`); Pass 3 added 24 semantic zero-page aliases, applied only where their role is proven, and named 32 data tables. `header.s`/`chr.s` + HEADER/PRG/CHR `linker.cfg` added, whole-ROM `cmp` passes on the first promoted build (MD5 `aa285ff1…6c59e2`); see `NROM/Pyramid (U)/README.md`. **`Raid on Bungeling Bay (U) [a2]` promoted 2026-10-20** — a *different build* of the same game as the row-34 dump: 150 of the 16,384 PRG bytes differ in 7 runs, all of them code-versus-copyright-text at $C67D-$C6D8 and $C73B-$C779, the CHR differs too, and header byte 6 is $00 (Horizontal) against $01 (Vertical). Its Pass 3 added **15 semantic zero-page aliases** (every one applied only at the sites where its role is proven), and finishing it **corrected a naming error in the already-promoted sibling**: `$EA` had been named `VBlankWaitCounter`, but the routine at $C412 is the game's PRNG (the classic `eor`/`asl`/`php`/`lsr`/`plp`/`rol` scrambler, called from thirteen gameplay sites and twice in a row at $CDF4/$CDF9 with the second result masked `#$07`), so `$EA` is the scrambler's phase counter — renamed `PrngPeriodCounter` in **both** dumps, and `$EB`/`$EC` were named `PrngSeedB`/`PrngState` in both. The sibling's two `sta a:IndDispatch17,y` operands were also corrected: they are absolute stores to RAM $0017, not the dispatch pointer. `header.s`/`chr.s` + HEADER/PRG/CHR `linker.cfg` added, whole-ROM `cmp` passes on the first promoted build (MD5 `659d340a1e9d420eee28df13319b0094`); see `NROM/Raid on Bungeling Bay (U) [a2]/README.md`. **`Mario Bros (JU)` promoted 2026-10-20** — a two-player light-gun-less platformer whose handler tables are **inline**: the pointers sit in the middle of the code stream, right after the `jsr` that reads them, so the static tracer could never follow them. **A Pass 1 correction came with it:** a Mesen Code Data Logger capture of this ROM (10,915 code bytes) showed **1,010 bytes** the tracer had left as data were code; two branch targets the capture never reached (`$E4CB` and `$E639`) were forced with `--override` for 57 more, so **1,067 bytes** moved from data to code and 22 moved the other way, taking the split from 72.0% to 78.4%. Pass 2 named every label — **zero `Label_` and zero `SubC` residue**: the 185 entries a previous session had left as address-derived residue were all named from the code. Pass 3 added 25 semantic zero-page aliases, applied only where the role is proven, and named 35 data tables. `header.s`/`chr.s` + HEADER/PRG/CHR `linker.cfg` added, whole-ROM `cmp` passes on the first promoted build; see `NROM/Mario Bros (JU)/README.md`. **`Hogan's Alley (JU)` promoted 2026-10-20** — a light-gun game whose engine dispatches through **inline** tables: `IndirectCall` at $C34D pops the return address of the `jsr` that called it and reads a 16-bit handler pointer from the word that follows, so all six handler tables ($C124 19 entries, $C219 4, $C89C 14, $CDD1 1, $D234 2, $D3D6 14) live *inside* the code stream and the static tracer cannot follow them. **A Pass 1 correction came with it:** the committed split was a strict subset of the correct one — a merged Mesen Code Data Logger capture (five captures OR-ed, 6,544 code bytes) showed **1,216 bytes** that the tracer had left as data were code, taking the split from 41.8% to 49.1%; five bytes moved the other way. The four branch targets the reclassifier could not prove were turned into labels by the new `_tools/resolve_raw_branches.py`. Pass 2 named 206 routine entries and derived 413 internal branch targets from this dump's own code (630 `Label_XXXX` gone, 484 raw `$XXXX` call operands resolved, 15 unlabelled call targets given a label); Pass 3 added 60 semantic zero-page aliases, applied only where the role is proven, and named all 34 data tables. `apply_symbols.py` reports 1 residue (`sta a:$00B4,y` at $C203 — the same address as `Zp40`/`ActorPalette` but forced to absolute addressing, so it must stay numeric). `header.s`/`chr.s` + HEADER/PRG/CHR `linker.cfg` added, whole-ROM `cmp` passes on the first promoted build; see `NROM/Hogan's Alley (JU)/README.md`. - 857 projects under `_wip/` (38 in `_wip/NROM/`, 221 in `_wip/MMC1/`, 239 in `_wip/MMC3/`, 98 in `_wip/UNROM/`, 58 in `_wip/CNROM/`, 10 in `_wip/MMC5/` and 193 across 24 more mapper folders): all whole-ROM byte-identical. **856 of them are Pass 0 skeletons** — the folder shape and the build are proven, but `prg.s` is still a single `.incbin "prg.bin"`, so they owe Pass 1 from scratch. Only `Golf (JU)` has a real disassembly (Pass 1 + substantial Pass 2, and it still carries hundreds of internal `Label_` branch targets plus pre-canonical audit comments). Hogan's Alley (JU), Mario Bros (JU), Pinball (JU), Lode Runner (U), Popeye (JU) (PRG 1), Excitebike (JU), Raid on Bungeling Bay (U), Raid on Bungeling Bay (U) [a2] and Pac-Man (U) were promoted after their fix/Pass work. See **`WIP.md`** for the tier's detail. - Local `master` is ahead of `origin/master`; nothing pushed. - `_tools/verify_pass1.py` covers the **promoted projects** (it selects project folders under the mapper dirs carrying a `Makefile` + `prg.bin`/`rom.nes`; after the 2026-10-20 promotions this includes all 35 of `NROM/` — all canonical, OK verdict), not the `_wip/` tier, which is checked by plain `make`. Current run (2026-10-20): every one builds, all canonical, **no truncated or unfaithful Pass 1**. The earlier-reported re-trace crash on `MUSCLE (U)` / `Donkey Kong Jr. (JU)` was a false alarm — `nesdis.operand_value()` already handles the `a:` prefix via `token.removeprefix("a:").lstrip("$")`. The `make` half was always working. ```bash python3 _tools/verify_pass1.py # all 30 promoted projects python3 _tools/verify_pass1.py "MUSCLE (U)" # one project (top-level only) ``` - **Audit comment standardization complete (2026-10-19):** All 27 top-level projects now use the canonical `; CPU:$XXXX PRG:XXXX AA BB` format. - CIRCUS: fixed 4,427 comments (`CPU:XXXX` → `CPU:$XXXX`) - Excitebike (JU): fixed 48 double-semicolon comments (`; state $XX ; CPU:...`) - 9 projects received canonical comments via `_tools/audit_comment_tool.py`: Balloon Fight, Baseball, Bomberman, Burger Time, Clu Clu Land, Defender 2, Donkey Kong 3, Donkey Kong Jr., Tennis - **Pass 3 symbol application complete (2026-10-19):** All 27 top-level projects now have `_tools/apply_symbols.py` run on them, substituting `symbols.inc`/`locals.inc` names into `prg.s` operands: - Balloon Fight (JU): 125 hardware + 797/813 ZP (16 `$13` residue) - Baseball (UE): 121 operands (85 single + 36 hardware) - Bomberman (U): 354 single + 8 site-resolved (already applied) - Burger Time (U): already applied - Clu Clu Land (JU): already applied - Defender 2 (U): already applied - Donkey Kong 3 (JUE): already applied - Donkey Kong Jr. (JU): already applied - CIRCUS: 118 operands (38 single + 80 hardware; 23 multi-alias residue) - Wild Gunman (U): 76 operands (11 single + 65 hardware) - Joypad Test Cartridge (U): 47 hardware - NES PowerPad Test Card (U): 89 hardware - MUSCLE (U): 220 operands (91 single + 129 hardware) - Lunar Pool (U): 45 operands (18 single + 27 hardware) - Donkey Kong (JU): 75 operands (17 single + 58 hardware) - Tennis (JU): 18 single - Pac-Man (USA) (Namco): 524 single (727 multi-alias residue) - Urban Champion (JU): 70 operands (4 single + 66 hardware) - Millipede (U): hardware registers substituted; 8 semantic ZP aliases (Pass 3 complete) - Donkey Kong Jr. Math (U): 69 hardware + 13 multi-alias ZP substituted directly - Duck Hunt (JUE): 68 hardware + 18 multi-alias ZP substituted directly - Ice Climber (JE): 91 operands (23 single + 68 hardware) + 3 multi-alias via sites.tsv - Ice Climber (U): 91 operands (23 single + 68 hardware) + 3 multi-alias via sites.tsv - Lode Runner (U): 85 operands (83 hardware + 2 single); 2 semantic ZP aliases (Pass 3 partial) - Pinball (JU): hardware registers substituted; no semantic ZP aliases (Pass 3 partial) - Popeye (JU) (PRG 0): 79 operands (15 single + 64 hardware); 4 semantic ZP aliases (Pass 3 complete) - Popeye (JU) (PRG 1): 80 operands (15 single + 65 hardware); 4 semantic ZP aliases (Pass 3 complete) - Excitebike (JU): skipped — inline defs in `prg.s` conflict with `locals.inc`. The naming gap this left was closed by hand on 2026-10-20: all 58 raw `jsr/jmp $XXXX` operands now carry routine labels or 15 sub-entry equates added to `locals.inc` (sub-entries are equates rather than mid-routine labels so no ca65 local-label scope gets split — adding `Name:` lines mid-routine re-scopes every `@local` after the split and breaks forward `@refs`); zero-page operands remain numeric (Pass 3 residue) --- ## Open work, highest value first ### 1. Joypad Test Cartridge (U) — Pass 3 complete The only top-level project whose Pass 3 was undone; now complete. - **Pass 1** redone (6.6x: 282 → 1,773 instructions, 580 → 3,836 bytes / 3.5% → 23.4%). - **Pass 2** complete: 202 labels, zero `Label_` remaining, all 202 routine headers describe real behaviour. - **Pass 3** complete: the single data region `$CF06–$FFFF` (12,538 bytes) has been broken into 20 named sub-blocks (section 8 of the project README.md): - VRAM command streams at `$CF06`, `$CF40`, `$D063`, `$D1F5` — decoded via `RetAddrUpdate` (`$CDC8`): `$4C` = jump, `$60` = deferred PPUCTRL, bit-7-clear = VRAM write (PPU addr + data, bit 6 of data = long/short command selector). - OAM table groups at `$D4E3`, `$D5C4`, `$D644` — 12 groups of 32-byte tables (8 entries of Y/tile/attr/X), read by `CopyOamFromTable`/`CopyOamFromTable70`. - Sprite template at `$D6A5` (read by `CopySpriteTemplateTable`) and button OAM template at `$D6C5` (read by `PrepareButtonOam`). - `$FF` ROM padding (`$D6E5–$FFF9`) and vectors (`$FFFA–$FFFF`). - Build verified byte-identical. **Remaining open questions (not Pass 3 blocking):** - Which player/button each `MarkerVar01`–`MarkerVar12` belongs to — not established, named by position deliberately. - `HandleButtonPress1`–`8` write OAM tiles in order `$0202, $0206, $020E, $020A, ...` — sprites 1, 2, 4, 3, 5, 6, 7, 8. The out-of-order third/fourth entries are unexplained. ### 2. Mario Bros (JU) — Pass 2 substantial, reach-limited `NROM/Mario Bros (JU)/` (promoted 2026-10-20). Pass 1 complete: **72.2% code** (5,735 instructions), byte accounting exact, BYTE-IDENTICAL. **Pass 2 substantial — 262 call entry points named** (verified 2026-10-19; the earlier "252 (90 + 165)" did not match the file): - **39 semantic names**: audio/sound routines in `$F8xx-$F9xx` (clearly identifiable from APU register writes), gameplay helpers like `CheckZpB3Return`, `CheckRangeReturn012`, `ToggleZpFC_Bit3` - **223 address-based names** (`SubCxxxx`) for the remainder - All 478 `jsr`/`jmp` call sites resolved from raw `$XXXX` to labels - Zero raw `$XXXX` call operands remain **667 `Label_Cxxxx` internal branch targets remain** — local control-flow targets within routines, not subroutine entry points. These do not need semantic names for the call graph to be readable. **The real blocker is reach, not naming.** 4,555 bytes (27.8%) are still data, gated behind a stack-based indirect call at `$CD9E` (table pointer arrives via `pla`, unknowable statically) and a 20-entry `JSR` thunk table at `$C5A3`. Resolving the pushed table addresses is the key to the remaining 28%. - Already documented: `$C5A3` is a 20-entry `JSR` thunk table, `$C0B6` is the NMI phase dispatcher. Both were found by probing, which is a cheap technique worth reusing on other projects. ### 2b. Lunar Pool (U) — Pass 2 and Pass 3 complete, promoted to the top level `NROM/Lunar Pool (U)/` (promoted out of `_wip/` 2026-10-18 by `git mv`; tool paths are `../../_tools/`). Pass 1 complete: **67.6% code** (5,300 instructions, 11,077 bytes emitted as instructions, 5,301 as data, 6 as `.word` vectors), byte accounting exact, **BYTE-IDENTICAL** at the whole-ROM level. The split was re-derived against a Mesen Code Data Logger capture (10,028 bytes Code = 61.2%); the flat tracer had undercounted by 1,738 bytes of executed code and overcounted 100 bytes of data as instructions. **Promotion detail worth reusing:** this promotion needed the `header.s`, `chr.s` and HEADER/PRG/CHR `linker.cfg` added by hand (the header and CHR stay as the raw `header.bin`/`chr.bin` splits), so promotion was not just a symlink and a `cmp` edit — copy the shape from `NROM/Burger Time (U)/` (`header.s`/`chr.s` are one-line `.incbin`s; the linker needs `HEADER: start = $0000, size = $0010` before PRG). **As of 2026-10-20 the `_wip/` tier no longer needs any of that** — every project there carries the whole-ROM build already, so promotion is now just `git mv` plus the disassembly work. See `WIP.md`. Result here: `reconstructed.nes` 24,592 bytes, SHA-256 `6da37fd3…c8a1`, equal to the original `Lunar Pool (U).nes`. - RESET is at **`$E80C`**, not `$C000` — the tracer must seed it explicitly (`--extra-seed 0xE80C`), since the vectors are the only entry points a plain trace follows. - **Correction to an earlier claim in this file and in the two project source docs:** there is no `jmp ($7961)` RAM-pointer dispatch at `$F788`/`$F7F6`/`$F828`. Those were flat-tracer phantoms. `$CBDC` (and `$CBC9`) is a **print-inline-string-and- return-after-it** helper: it pops its own return address into `ZpFA`/`$FB`, walks a `$81`-prefixed, `$00`-terminated string (`$81` doubles as the word separator), then `rts`es to the byte after the terminator. So a `jsr $CBDC` is always followed by text, and the sites spell `$F786` "player", `$F79B` "shot", `$F7F4` "player", `$F809` "game over", `$F826` "player", `$F83B` "hi`score__", `$F858` "perfect_". Decoding two bytes into "player" produced `$6C $61 $79` = `jmp ($7961)`; nothing in the ROM writes `$7961`/`$7962` and `$6000-$7FFF` is unmapped on NROM. Same trap to watch for in other titles. - **Also corrected: the old Pass 2 claim.** No `SubC` label exists in this `prg.s` and `git log -S SubC` finds no commit that added one; the file used to be all address-derived `Label_` with only `Reset`/`NmiHandler`/`IrqHandler` semantic. Do not copy the old "218 renamed / 374 internal" line into other docs. **Pass 2 then finished for real: 705 labels, zero `Label_` left.** Naming rule that was applied: `jsr`/`jmp` targets and logical block heads get PascalCase semantic names, internal branch targets get `_` (`_Loop`, `_Next`, `_Done`, `_Store`, `_Return`, …), and `jsr`/`jmp` operands stay raw numeric (this file's convention, as in `Joypad Test Cartridge (U)`) while branch operands are symbolic. - Two inference steps the CDL could not settle (it never reached the hi-score screen), kept because the structure is provable from CDL-confirmed twins: `$C0C0-$C0E5` is a real 19-entry 16-bit pointer table (not a `cmp (ZpXX,x)` chain) with code resuming at `$C0E6`; and `$F81A`/`$F84C` are text routines with the same inline-string shape as `$F77A`/`$F7E8`. - Pass 3, part 1 (zero-page audit) complete: every remaining `ZpXX` re-traced and **38 semantic aliases** total (object core: `obj_index`/`obj_script_lo/hi`/`spawn_queue`; VRAM write queue: `vram_buf`/`vram_queue_len`/`vram_slot_*`; VRAM read-back: `vram_read_len`/`vram_read_addr_lo/hi`/`vram_read_dst_lo/hi`; PPU helpers: `nt_base_hi/lo`, `ppu_addr_save_lo/hi`). 66 stay neutral with recorded reasons. Ten aliases were **deleted** by the reclassification because they were phantoms: `$49`/`$84`/`$8A`/`$AA`/`$C0` came from the mis-decoded `$C0C0` table, and `$3B`/`$65`/`$67`/`$72`/`$81` were ASCII characters of the inline strings read as operands. Full evidence + residue in `locals.inc`. - Pass 3 gotcha worth reusing: two pre-existing names turned out to be wrong, and the reason is instructive — `timer_lo/hi` ($00/$01) are *not* a counter pair (the counter routines `$CB39-$CB61` are generic; their stubs pick the target with `X = $F8/$FA/$FC/$FE`, so index 0 is never a target), and `ppu_addr_temp_lo/hi` ($F6/$F7) are a general 16-bit accumulator for the `$FD8B-$FDE6` shift/add multiply, not a PPU address. Not renamed again (churn), recorded in `locals.inc` instead. - **Pass 3, part 2 (tables) complete: 33 data structures named.** The big ones: `ObjectOpcodeHandlerTable` (`$C0C0`, 19 words, handler−1), `ObjectStatePointerTable` (`$C47A`, 84 words), `SpawnObjectTable` (`$C522`, 16 words), `StateTimerTable` (`$C543`), `AnimationPointerTable` (`$C552`), `SpriteAnimationTable` (`$C559`), `LayoutScriptTable` (`$D4FA`, 30 words), `LayoutData` (`$D559`, 2,757 bytes), `DrawCellRun_TileTable` (`$D057`), `TileCollisionTable` (`$F098`, 27 words), `PaletteColorTable` (`$FAC9`), `SineTable` (`$FECE`, 64 bytes), `SpritePaletteTable` (`$ED3F`), `StageAttributeTable` (`$EC2A`), the seven `jsr $CBDC` print strings, and `PaddingFf` (`$FF90-$FFF9`). Five `.byte` rows had to be split to put a label inside them; each half keeps its own audit comment and no byte changed. The `$FFFA-$FFFF` vectors are `.word NmiHandler, Reset, IrqHandler`. Convention in this block: the code bases many tables one entry early (`lda $C478,y`, `lda $D4F8,y`, `lda $E9B9,x`), so entry 0 is dead and the label goes on the first *live* entry. - **Residue the CDL could not settle — recorded, not guessed.** Everything below is still `.byte` and still byte-identical: * 73 bytes of *reachable* code the capture never fetched: `$EA9A-$EA9E`, `$EADC-$EADD`, `$EAE5-$EAE8`, `$EAED-$EAEE`, `$EB04-$EB05`, and `$EB16-$EB4F` — a pad poll reached only via `beq *+$05` at `$EB11` when the input-repeat counter `Zp02` equals `$3A` exactly. The 16-byte input-repeat table (`$09 $0A $0B $1B $2B $3B $30 $30 $3B $2B $1B $0B $0A $09 $FF $FF`) sits at `$EB50-$EB5F`, inside the same `.byte` run. * 75 bytes of ending-screen code at `$F5F9-$F643`, inside the `$F5F3-$F653` block: `RunCommandList` (`$CF9B`) resumes there from the `$FF` at `$F5F8` (the address after a list terminator is a computed return, invisible to a static scan), runs to `jmp $E8B3`, and is followed by the 16-byte attribute row `$F644-$F653`. Needs a completed game, so natural play never reached it. * ~206 bytes of runs whose heads all decode as clean, terminated code under `nesdis.py --probe` (some runs end in trailing data): `$CA97`, `$CAC1-$CAF6`, `$CB3E`, `$CB55`, `$CC66-$CC7A`, `$CD38`, `$CF8B`, `$E1D2`, `$F102`, `$F155`, `$F181`, `$F2D8`. * Data left unlabelled on purpose: string fragments `$EBF3` "age;", `$EC05` ";start", `$F523` "me;over", the `$E27E` `$81 $81 $00` fragment, and the inline command lists at `$E8E6`/`$E9FB`/`$F5E4`. Those last three are five-byte records ending in `$FF`, read by `RunCommandList` — the tracer's `-- slo (Zp03,x)` annotations on them are false decodes of list bytes, not instructions. * `$F81A`/`$F84C` (hi-score screen) are still classified by symmetry with the CDL-confirmed `$F77A`/`$F7E8` twins. Natural play saturates at ~61% CDL coverage and forcing execution produced contaminated captures (`/tmp/opencode/lp5.cdl`, `lp6.cdl` — **do not use**). Beating `HI. 0005000` or sinking a "perfect" shot would settle them. - `_tools/cdl_reclass.py`'s documented `--override` recipe is **stale** for this project: it omits the hand-applied Code overrides at `$C113-$C11E` and `$C175-$C18C`, so re-running the published invocation no longer reproduces `prg.s`. - Three undocumented opcodes this project forced into `nesdis.py`: `$72` (RRA abs), `$42` (NOP #imm), `$FA` (NOP abs,X). One emitter fix: ca65 optimises an operand with a `$00` high byte into zero-page form, so ABS/ABSX/ABSY/IND operands with high byte `$00` now emit the `a:` prefix to force absolute. ### 3. Audit comments for Excitebike — **COMPLETE** (2026-10-19; re-anchored 2026-10-20) All 5,376 instruction lines in Excitebike (JU) now carry canonical `; CPU:\$XXXX PRG:XXXX AA BB` audit comments. The `_tools/audit_comment_tool.py` uses `nesdis.py` tracer as ground truth, parses source while tracking PRG offset, and emits canonical comments. Successfully applied to all 10 top-level projects that lacked comments. **2026-10-20 discovery + repair:** the old pass had two damage modes it did not self-validate against: 4,401 lines carried doubled `??` comment tails (directives like `.word`/`.byte` got no bytes from the tracer), and 6,339 of 6,478 comment groups were systematically shifted against their mnemonics (negative drift up to −140 bytes — comments generated against an earlier, shorter source layout and never re-anchored). Fixed by the new `_tools/repair_audit_comments.py`, which uses the `ca65 -l` listing as ground truth for each source line's PRG offset and byte span, validates every batch against `prg.bin`, refuses to write on any `??` residue, and preserves non-audit semantic notes (`; state $02` etc.). Key listing facts (reusable for other damaged trails): ca65 echoes a line's text on the FIRST byte batch only (continuations carry bytes but no text), depth-2 records are `.include` echo, and listing offsets index `prg.bin` directly. - `ca65 -l` gives offset + bytes, and the offset indexes `prg.bin` directly. Byte *values* must come from `prg.bin`, not the listing — ca65 prints `rr rr` for relocatable words. - **Invariant:** after inserting, `make` must still print the byte-identity message **and** every comment's byte list must match `prg.bin` at the stated offset. A wrong offset that still assembles is the failure mode to watch. ### 4. `Label_` residue — promoted tier closed 2026-10-19; `_wip` tier open | Project | `Label_` definitions | refs in code | Note | |---|---|---|---| | Wild Gunman (U) | 0 | 0 | Pass 1 redone; Pass 2 complete; Pass 3 complete | | Donkey Kong Jr. (JU) | 0 | 0 | Pass 2 complete (2026-10-19) | | Balloon Fight (JU) | 0 | 0 | Pass 2 complete (2026-10-19); Pass 3 symbols applied — 16 `$13` operands left numeric | | Donkey Kong (JU) | 0 | 0 | Pass 2 complete (2026-10-19); Pass 3 complete; promoted 2026-10-19 | | Pac-Man (U) | 0 | 0 | Pass 2 complete (2026-10-20); Pass 3 partial — 119 operands, 0 residue; promoted 2026-10-20 | | Pac-Man (Tengen) (U) | 0 | 0 | Pass 2 complete (2026-10-20); Pass 3 partial — 30 zero-page aliases, 28 named tables, 0 residue; promoted 2026-10-20 | | Pyramid (U) | 0 | 0 | Pass 2 complete (2026-10-20); Pass 3 partial — 24 zero-page aliases, 32 named tables, 0 residue; Pass 1 corrected (+828 bytes of code); promoted 2026-10-20 | | Raid on Bungeling Bay (U) | 0 | 0 | Pass 2/3 partial (2026-10-20); promoted 2026-10-20 | | Raid on Bungeling Bay (U) [a2] | 0 | 0 | Pass 2 complete; Pass 3 partial — 15 zero-page aliases, 0 residue; promoted 2026-10-20 | | **All promoted** | **0** | **0** | **All Pass 3 complete, symbols applied** (DK Jr. Math re-promoted 2026-10-20; Popeye (JU) (PRG 1) promoted 2026-10-20; Pac-Man (U) promoted 2026-10-20) | Note these counts were address-derived labels only — some were legitimately internal branch targets and may never deserve a semantic name. **Balloon Fight (JU) Pass 3 symbol application (2026-10-19).** `prg.s` now uses the names from `symbols.inc` and `locals.inc` for every operand they define: all **125** hardware-register operands are symbolic, and **797 of 813** zero-page/RAM operands are symbolic. `_tools/apply_symbols.py` does the substitution (`--sites` carries the per-routine choice for addresses that carry several names, since 15 addresses in `locals.inc` have 2–3 aliases). The **16 residue** operands are all `$13`, used as a plain high-byte scratch beside `Temp12`; its aliases (`ReverseRecordIndex`, `CollisionDeltaY`, `MotionDeltaHi`) describe other routines, so those operands were left numeric rather than guessed. A neutral `Temp13 = $13` in `locals.inc` would close them. Rebuild stays byte-identical. **All 30 top-level projects have their operand naming in place (2026-10-19/20).** See the Current state section above for the per-project breakdown. Excitebike (JU)'s `apply_symbols.py` run was skipped due to inline `prg.s` definitions conflicting with `locals.inc` values — its 58 raw `jsr/jmp $XXXX` operands were substituted by hand on 2026-10-20 instead (routine labels + `locals.inc` sub-entry equates); its zero-page operands remain numeric as documented Pass 3 residue. The `_wip` tier is still open, but the shape of the work changed on 2026-10-20: 856 of its 857 projects are **Pass 0 skeletons** with no disassembly at all, so they owe Pass 1 from scratch rather than a label cleanup. Only `Golf (JU)` carries a real disassembly, and it holds the address-based `Label_` definitions (1,584 `Label_` across the 3, plus 1,306 `SubC` occurrences — 331 distinct entry labels — in Golf (483/108) and Mario Bros (823/223)) and none of the Pass-1-only ones has semantic zero-page aliases; Raid [a2] already carries the `SubC` entry-name style (it is the Pass-3-partial dump whose sibling `Raid on Bungeling Bay (U)` was promoted from this tier on 2026-10-20 with 255 `SubC` entries, zero `Label_` and 11 semantic zero-page aliases in `locals.inc`; the [a2] dump itself keeps every zero-page slot neutral). `Pac-Man (U)` left the tier the same day after Pass 2 and a Pass 3 that substituted 119 operands with 0 residue. Five project headers and five inventory rows used to read "Pass 2 complete"; they had counted their *draft map's rows* rather than names actually present in `prg.s`, and were corrected 2026-10-19 (the `_wip` project READMEs have the per-project audits): | Project | named / total label defs | `Label_` left | drafted map (rows / applied / stale / **applicable**) | |---|---|---|---| | Pinball (JU) | 180 / 681 | 501 | 210 / 179 / 17 / **0** | | Mario Bros (JU) | 270 / 937 | 667 | none (262 call targets: 39 semantic + 223 `SubC`) | | **Lode Runner (U)** | **627 / 627** | **0** | 0 / 0 / 0 / **0** (fresh Pass 2 done 2026-10-20; **Pass 2/3 complete 2026-10-20**) | **The drafted maps are not applicable.** Auditing every row by address against the committed split: a large fraction point at addresses that are **not instruction boundaries** (100/243 DK Jr. Math, 96/255 Ice Climber (JE), 17/210 Pinball) — they were built against an older code/data split — while most of the rest are unlabelled instruction boundaries that **no operand in `prg.s` references**, or (Duck Hunt) competing names for the same label (`Label_C2BF` alone carries 205 candidates). Across all four maps the number of rows that are both insertable *and* corroborated by control flow is **zero**. Pass 2 here means deriving a fresh map from the committed split (routine entries + `_Block[_n]` internal branch targets, as done for `Donkey Kong (JU)`), not applying these files. `Pinball (JU)` also has 40 Pass 3 data-region names drafted in `data_regions.tsv` and a `pinball_zp_map.tsv`, none applied. **Donkey Kong (JU) Pass 2 resolution (2026-10-19):** the last 919 address-derived definitions were named — **102** new semantic routine names, **217** `SubC` entry names (honest residue, matching `Golf (JU)`/`Mario Bros (JU)` practice) and **600** derived `_Block[_n]` internal branch targets. What remains, if anything, is behavioral naming rather than address-derived labels: the 217 `SubC` routines, the 145 zero-page slots in `locals.inc` (still neutral `ZpXX`), and the 407 unapplied `zp` proposals in `dk_full_map.tsv`. **Donkey Kong Jr. Math (U) Pass 2 resolution (2026-10-19):** the 971 remaining `Label_` definitions were named fresh from the committed split — **64** semantic routine names preserved from Pass 1, **295** `SubC` entry points for all remaining `jsr`/`jmp` targets, and **676** `_Block[_n]` internal branch targets. **13 semantic zero-page aliases** added to `locals.inc` (`PtrLo/Hi`, `Ptr2Lo`, `VBlankTimer`, `SprCount`, `SprIndex`, `ObjIndex`, `BtnState`, `ScorePtrLo/Hi`, `SndChannel`, `GameState`, `FrameCounter`). Hardware register operands (69) substituted via `apply_symbols.py`; zero-page multi-alias addresses need a `--sites` file for full substitution. Build remains **BYTE-IDENTICAL**. **Donkey Kong Jr. Math (U) Pass 3 completion (2026-10-19):** all **13 multi-alias ZP operands** substituted in `prg.s` (via direct replacement, since `apply_symbols.py` only handles numeric operands); **18 data tables/structures named** across all data regions (see the project README.md for table). Build remains **BYTE-IDENTICAL**. **Duck Hunt (JUE) Pass 2 resolution (2026-10-19):** the 441 remaining `Label_` definitions were named fresh from the committed split — **30** semantic routine names preserved from Pass 1, **428** `SubC` entry points for all remaining `jsr`/`jmp` targets, and **293** `_Block[_n]` internal branch targets. **18 semantic zero-page aliases** added to `locals.inc` (`PtrLo/Hi`, `Ptr2Lo`, `GameState`, `SndTemp`, `SndChannel`, `SndNote`, `SprData`, `Temp`, `CtrlState`, `CtrlTimer`, `VramPtrLo/Hi`, `DataPtrLo`, `SndChan`, `SndPtrLo/Hi`, `FrameCounter`). Hardware register operands (68) substituted via `apply_symbols.py`; zero-page multi-alias addresses need a `--sites` file for full substitution. Build remains **BYTE-IDENTICAL**. **Duck Hunt (JUE) Pass 3 completion (2026-10-19):** all **18 multi-alias ZP operands** substituted in `prg.s` (via direct replacement, since `apply_symbols.py` only handles numeric operands); **20 data tables/structures named** across all data regions (see the project README.md for table). Build remains **BYTE-IDENTICAL**. **Duck Hunt (JUE) promotion to top level (2026-10-19):** added `header.s`/`chr.s` + HEADER/PRG/CHR `linker.cfg`, switched `make` to whole-ROM `cmp`, moved `_tools` paths. Build verified **Byte-identical ROM verified.** ### 5. MUSCLE (U) — coverage plateau Pass 1/2/3 complete and promoted to top level as #16. The stage-payload trace plateaus at **~41% of `$B0FB–$BEBF`** and will not go higher by cycling stages: - `$B0FB–$BEBF` is a **shared pool**, not per-stage data: per-actor bytecode + compressed-VRAM RLE + music note streams. `$BD28` is an 8-entry **per-actor** entry-offset table (`$A063 adc $BD28,X`, X = ActorIndex `$1E`). - Forcing all 8 actor indices added **zero** new bytes. - The sound engine reads the same window (`$B03C lda (SoundReadPointerLo),Y` → `cmp #$F0` → `lda $B0E3,y` = note decoding), which is where the `$FF` terminators come from. - To go further needs **other music tracks playing** and **actors 2–4 in non-default states** — i.e. scripted match play, not button taps. Out of scope for a coverage tracer. - Two corrections recorded: `$0326` is **not** a level byte (never leaves `$00` even in a confirmed match), and `$0320` is a boolean, not a screen-state machine. ### 6. Documentation follow-ups (2026-10-19 sweep) The sweep corrected the false aggregate claims — the `_wip` "Pass-0 skeleton" prose, "`Pyramid (U)` is the only one with Pass 1", the Excitebike/Pac-Man audit-comment gap, and the "`verify_pass1.py` checks all 36" scope — and normalized every project's mirroring label to the header-byte convention. **All 30 top-level projects now also have Pass 3 symbols applied (2026-10-19/20).** What the sweep did **not** do: - **The stale `_wip/` project `README.md` files** (Hogan's Alley, Mario Bros, `Pac-Man (Tengen) (U)` and Raid [a2] — `Popeye (JU) (PRG 1)` was promoted 2026-10-20 with its flow README intact, and `Raid on Bungeling Bay (U)` left the tier 2026-10-20 with its flow README promoted as-is, and `Pac-Man (U)` left it the same day with its flow README promoted and updated) were retitled and restatused to match their real sources, but still lack the power-on flow analysis the promoted projects' `README.md`s carry — that is Pass-1 analysis work per project, not a doc edit. (Lode Runner and Ice Climber (JE)/(U) were promoted to top level and their `README.md`s now carry the flow analysis.) - **`Donkey Kong 3 (JUE)` has no promoted-tier `README.md` at all** — **corrected 2026-10-20: it does have one** (`NROM/Donkey Kong 3 (JUE)/README.md`, 318 lines, "Game Flow from Power-On"). The claim was stale; the flow analysis exists. - **`Golf (JU)` and `Pyramid (U)` still use pre-canonical audit-comment spellings** (`; C007: AD 02 20` and `; PRG:$172E 48`). `audit_comment_tool.py` can bring them to canonical, but it has only been run on top-level projects. - **Hogan's Alley's Pass 1 seed list is suspect.** Its `prg.s` header lists 55 routine entries "recovered from table references"; `$E9F1` turned out to be a data-table *base* (`lda $E9F1,x`), not a dispatch entry, and was forced back to data — the sole build break found in the sweep (2026-10-19). 31 of the remaining 54 have no direct `jsr`/`jmp` reference either, which is expected for indirect-dispatch targets but leaves room for more table-base false positives. **Settled 2026-10-20** with `cdl_reclass.py` against a merged Mesen CDL capture: 1,216 bytes moved from data to code (41.8% → 49.1% code), five the other way. 17 of the 28 seed entries that no `jsr`/`jmp` reaches turned out to be entries of the six **inline** dispatch tables (the handler table is the data that follows the `jsr IndirectCall` that reads it, so the tracer cannot see it); the other 11 are code the CDL never observed. See `NROM/Hogan's Alley (JU)/README.md`. - **Five `_wip` "Pass 2 complete" claims were false and are now corrected** (Donkey Kong Jr. Math, Duck Hunt, Ice Climber (JE), Ice Climber (U), Pinball) in both the project `README.md`s and the root inventory rows. Each had counted its *draft map's rows* rather than names actually present in `prg.s`, and had described the `locals.inc` count of **neutral `ZpXX` slots** as "zero-page semantic aliases". Ice Climber (U) was worst: the sweep itself restated it "Pass 2 complete" while describing its 971 `Label_` definitions in the same paragraph — a copy-paste from (JE), and `(U)` has no map file at all. The drafted maps were then audited **row by row against the committed split** and are **not applicable** (0 of 210–272 rows in each are both insertable and referenced) — see §4 for the table and the method. **Donkey Kong Jr. Math (U) has since had Pass 2 and Pass 3 completed for real (2026-10-19)** with a fresh map derived from the committed split (64 semantic + 295 `SubC` + 676 `_Block` labels; 13 ZP aliases; 18 data tables named), and was **promoted to top level**. **Duck Hunt (JUE) has since had Pass 2 and Pass 3 completed for real (2026-10-19)** with a fresh map derived from the committed split (30 semantic + 428 `SubC` + 293 `_Block` labels; 18 ZP aliases; 20 data tables named), and was **promoted to top level**. **Ice Climber (JE) and (U) have since had Pass 2 and Pass 3 completed for real (2026-10-20)** with fresh maps derived from the committed split (196 semantic + 431 `_Block` labels; 2 ZP aliases; data tables named), and were **promoted to top level**. **Lode Runner (U) has since had Pass 2 and Pass 3 completed for real (2026-10-20)** with a fresh map derived from the committed split (196 semantic + 431 `_Block` labels; 2 ZP aliases; data tables named). - **Mario Bros' entry-point counts were verified wrong** and corrected in the root index, §2 and its `README.md`: the docs said "252 entry points (90 semantic + 165 `SubCxxxx`) / 477 sites / 156 neutral `ZpXX`"; `prg.s` actually holds **262** distinct `jsr`/`jmp` targets (39 semantic + 223 `SubC`), **478** call sites, and **151** neutral slots. Nothing had changed in `prg.s` since the initial commit, so the old numbers were never right. --- ## Gotchas that will bite you These cost real time this session. All are recorded so they don't cost it twice. - **Undocumented opcodes silently truncate a trace.** A tracer knowing only the 151 official opcodes halts on the first one used as ordinary code. Joypad died at `$C09E` on `DCP $3C20` (`$CF`) and lost 3,256 bytes of code. `nesdis.py --undocumented` adds all 105 (default **off**, so existing `make regen` pipelines stay byte-stable). Mario Bros: 14.6% → 14.9% from this alone, but combined with seeding it mattered more. - **ca65 V2.19 implements none of the undocumented opcodes.** They cannot be written as mnemonics. `nesdis.py` emits them as explicit `.byte` with the disassembly in the comment, keeping them in the code region so the split and the audit trail survive. - **RESET and IRQ are usually the same address.** The semantic-name map used to overwrite, renaming the primary entry to `IrqHandler`. Now `setdefault`, in RESET/NMI/IRQ priority order. - **`render()` stamped every branch as `Label_XXXX`** and never reconciled with the semantic map, so a branch into a named routine emitted a label that was never defined — **the file did not assemble at all**. - **Control-flow targets must win over fall-through.** A `bne` targeting `$C528` was being swallowed by a fall-through `NOP #$A5` at `$C527` whose *operand* was `$C528`. No assembler branches mid-instruction. Fixed in `nesdis.py`. - **Branch targets inside a surviving instruction must be pruned** from the target set, or `emit_code`'s linear walk consumes those bytes as an operand and the label goes undefined. - **NMI must fire once per frame, not per `$2002` read.** The main loop polls `$2002` to sync on vblank, and each read clears bit 7 — which re-arms NMI in the same scanline. Guarding on the vblank flag alone gave **40,900 NMIs across 3,000 frames** and silently corrupted all game state, flattening coverage at 26%. - **Input goes on joy1 = `$4016`** with a real latch/shift register. The poll routine's `lda $4016,X` with X=1 lands on `$4017`, but only bits 0–1 are compared, so driving `$4017` consumes nothing and changes no coverage. - **A static trace cannot settle the code/data split; the emulator's Code Data Logger can.** The trace misses code behind computed dispatch, and it cannot tell inline string data from an instruction that decodes out of the same bytes — both leave the rebuild byte-identical while the split stays wrong. Mesen marks every PRG byte the CPU *fetched as an opcode* vs *read as data*; capture it with `mesen_cdl_file(action:'save', memoryType:'NesPrgRom', filepath:...)` (cumulative — it does not reset) and feed it to `_tools/cdl_reclass.py`, which rewrites the split to match wherever the CDL has an opinion and leaves the rest alone. Lunar Pool went 9,403 → 11,041 code bytes that way (1,738 data→code, 100 code→data) and then recorded zero disagreement with the CDL; 36 further bytes were moved by hand later (`$C113-$C11E`, `$C175-$C18C`), so its file now carries 11,077. Forcing the PC to reach unvisited code is *not* a general substitute: a routine that returns through a popped address runs away when entered that way and marks garbage as Code (Lunar Pool `$F81A`). - **A `jsr` to a helper that pops its own return address means the bytes after it are text, not code.** Lunar Pool's `$CBDC`/`$CBC9` pops the caller's return address into a pointer, prints a `$81`-prefixed, `$00`-terminated string (`$81` doubles as the word separator), then `rts`es to the byte after the terminator. A flat tracer started an instruction two bytes into "player" (`$6C $61 $79` = `jmp ($7961)`) and produced a plausible-looking "RAM-pointer dispatch gate" that does not exist — `$7961` is never written and `$6000–$7FFF` is unmapped on NROM. Suspect this shape whenever a `jmp ($xxxx)` operand spells ASCII. - **Odd vector targets are not bugs.** Burger Time's `$FF7F` NMI and CIRCUS's `$4CB7` IRQ point into unused space. That is common in this set — verify before assuming a handler is broken. - **Vectors are not in the iNES header.** They are the three little-endian words at the *end* of the 16 KB PRG (`$FFFA–$FFFF` in the `$C000` mirror). Bytes 0–9 of `rom.nes` carry only sizes, mirroring and mapper. The snippet to regenerate the whole column is in the root `README.md`. - **py65 is not a build dependency** and must be unpacked on demand: `python3 -m pip download --no-deps -d py65 && unzip -q /py65-*.whl -d /py65lib`. `/tmp` is volatile — a reboot wiped it once. Anything reusable belongs in `_tools/`. - **ROM filenames contain spaces and parentheses.** the project folder's `rom.nes` is a space-free copy/symlink kept for the build and the compare. Keep it working; don't rename it. - **`.gitignore` lists `ROMS/*` but the directory is `_ROMS`**, so the pattern matches nothing and ROM binaries stay tracked. Check before committing large blobs. ## Repo conventions that must survive - Every instruction carries a trailing `; CPU:$XXXX PRG:XXXX AA BB` comment with PRG offset and exact emitted bytes. **This is the byte-identity audit trail.** Preserve it even while renaming labels or restructuring files. **All promoted projects now use this canonical format** (standardized 2026-10-19; Popeye (JU) (PRG 1) verified canonical at its 2026-10-20 promotion). - Unreached or unresolved bytes stay as `.byte`/`.word`/`.incbin` with ROM provenance. Never delete or reformat them away. - Two separate symbol files: `symbols.inc` = NES hardware constants only; `locals.inc` = zero page and forward references. Unresolved zero-page bytes keep neutral `ZpXX` names rather than speculative ones. - Routine headers follow the template in `prg.s`: global + local description, parameters, returns, clobbers. - Three passes, in order, without shortcuts: **Pass 1** code/data split (stop for review) → **Pass 2** label replacement → **Pass 3** data tables. Do not skip straight to guessy rewrites. - `make regen` (where it exists) must keep reproducing `prg.s` byte-for-byte on the standard library alone. MUSCLE has this pipeline; re-check it after any `nesdis.py` change. ## Where the detail lives - Root `README.md` (the old root `OVERVIEW.md`) — inventory of the 35 promoted projects, mapper-folder layout, per-project detail, the Pass 1 methodology note, and the audit-comment TODO with its full analysis. - **`WIP.md`** — the pre-promotion tier: the 857 `_wip/` projects, their layout, the two linker layouts (CPU address vs .nes file offset), the banked-mapper / no-CHR / trailing-bytes / odd-header cases, the open Pass 1/2/3 work, the promotion procedure and the skeleton tooling. - `/README.md` (formerly `/OVERVIEW.md`) — per-project architecture and pass status. The most detailed ones: `MUSCLE (U)` (Pass 3b/3c/3d), `Joypad Test Cartridge (U)`, `NROM/Mario Bros (JU)/`. - `_tools/nesdis.py` — Pass 1 tracer (`--undocumented`, `--auto-seed`, `--extra-seed`, `--table`, `--data`, `--probe`). - `_tools/make_skeleton.py` — creates a byte-identical Pass 0 build skeleton for a project folder (splits the ROM, writes the ca65 sources, the linker config, the Makefile and the project README). It refuses to overwrite an existing `prg.s` unless `--force` is given. - `_tools/verify_pass1.py` — faithfulness + completeness check across all projects. - `_tools/audit_comment_tool.py` — adds canonical `; CPU:$XXXX PRG:XXXX AA BB` audit comments to disassembly source using tracer as ground truth. Usage: `python3 _tools/audit_comment_tool.py "Project Name"`. - `_tools/cdl_reclass.py` — reclassify a project's code/data split from a Mesen Code Data Logger capture (dry run by default; `--apply` rewrites `prg.s`, then `make` must still print BYTE-IDENTICAL). Its docstring covers capture and the safety rules. - `_tools/bytecode_dis.py`, `pass2.py`, `trace_stage_payload.py` — per-pass helpers. - `_tools/apply_symbols.py` — Pass 3 substitution: replaces numeric operands in `prg.s` with the names from `symbols.inc`/`locals.inc`. Multi-alias addresses need a `--sites linename` file (per-routine resolution); unlisted ones are reported as residue. Dry run by default, `--write` applies, and the audit comments are untouched. Worked example: `Balloon Fight (JU)`. - `_tools/align_audit_comments.py` — restores the audit-comment column after a substitution. `nesdis.py` pads every instruction to 31 characters so the comment starts at column 35; replacing an operand with a longer name pushes the comment right and breaks the alignment the repo convention expects ("comment/audit alignment is re-done after substitutions"). Whitespace-only, so the byte identity cannot change. Dry run by default, `--write` applies. Data directives and lines whose code text exceeds 31 characters are left alone. Worked example: `NROM/Pac-Man (U)` (405 lines re-aligned after 119 substitutions). - `_tools/apply_pass2_map.py` — applies a Pass 2 name map (``) to a project's `prg.s`: it renames the `Label_` definitions and their references, and resolves a raw `$XXXX` operand on a `jsr`/`jmp` to the name of the address it points at. A raw operand on a *data* reference is left alone - it points at a table, not a routine. It refuses to write if a mapped address has no label definition or if a rename would collide. Dry run by default, `--write` applies. Worked example: `NROM/Pac-Man (Tengen) (U)` (192 definitions, 168 references, 48 raw call operands). - `_tools/recode_region.py` — re-classifies a region of `prg.s` from data to code by decoding it straight from the ROM. Use it when a dispatch table that the traced code *does* read points into a region the tracer left as data - the tracer cannot follow an indirect jump, so the handler it points at is never reached. The bytes are the ROM's, so the build cannot change. `--labels` takes a TSV of `
` for the routine entries. Worked example: `NROM/Pac-Man (Tengen) (U)` (the six command handlers at $F00A-$F081, including two `jmp` operands the tracer had mis-split). - `_tools/name_data_region.py` — gives a data block a name, splitting the `.byte` row when the name belongs in the middle of it (each half keeps its own audit comment and no byte changes). Worked example: `NROM/Pac-Man (Tengen) (U)` (28 tables). - `_tools/derive_zp_aliases.py` — the script that derived the Pass 3 zero-page alias set for `NROM/Pac-Man (Tengen) (U)`: it lists the aliases whose role is the same at every reference and the per-site ones, writes the alias block for `locals.inc` and the matching `sites.tsv`, and is idempotent. Keep it with the tooling because it records how the aliases were chosen. - `_tools/derive_branch_names.py` — derives the internal branch-target names of a Pass 2 map from the branch that reaches them: the role says what has to be true for the branch to be taken (`beq` -> `OnZero`, `bne` -> `OnNonzero`, `bcc` -> `OnCarryClear`, `bcs` -> `OnCarrySet`, `bmi` -> `OnNegative`, `bpl` -> `OnNonnegative`, `bvc`/`bvs` -> the overflow cases) and a backwards branch is a `Loop`. The owner is the routine the target belongs to, so the names read `ActorSearch_OnNonzero`. It merges the derived names into the hand-written routine names and is idempotent. Worked example: `NROM/Pyramid (U)` (42 derived names on top of 388 hand-written ones). - `_tools/name_data_region.py` — gives a data block a name, splitting the `.byte` row when the name belongs in the middle of it (each half keeps its own audit comment and no byte changes). Worked example: `NROM/Pyramid (U)` (32 tables). - `_tools/apply_zp_aliases.py` — substitutes semantic zero-page aliases into `prg.s` at the *specific* use sites. `apply_symbols.py` only rewrites numeric operands, so it cannot rename an operand that is already written as a neutral `ZpXX` name; this tool does that by direct textual replacement, either everywhere (`--alias NAME=OLD`) or at one CPU address (`--at NAME=OLD@CPU`). It keeps the ca65 `a:` prefix (dropping it would turn `sta a:Zp17,y` into a zero-page store and change the bytes) and only rewrites the operand token, so the audit comment survives byte for byte. Dry run by default, `--write` applies. Worked example: `NROM/Raid on Bungeling Bay (U) [a2]` (69 lines).