Drew T
e936556ff0
seed_ref answers 'is there a byte-identical twin?'. This answers the weaker but far more common question: 'which matched function should I READ before drafting this?' S68 measured a ~20x swing on that variable. Every cheapest large match came from an agent finding a matched neighbour (func_800D1254 555 ins/72k; func_800D12D0 657 ins/122k FIRST COMPILE; func_8018AD9C 397 ins/87k; func_8017BEBC 753 ins/177k), while main functions with no neighbour ran 200-350k for ~80 instructions. THE FAILURE THAT MOTIVATED IT: func_8017BEBC's card asserted 'no banked twin' while a MATCHED 755-instruction near-twin sat 3,700 lines up IN ITS OWN FILE, its header comment documenting the four levers the target needed. seed_ref joins on signature hashes and the two bodies are not hash-identical, so it was structurally invisible. Three other S68 agents found their unlock the same way, unprompted. Ranks on what actually worked, not intuition: SAME TU first (solved against the same decl environment, and its header records the levers), then same binary, then shape (li-normalised skeleton / call-sequence hash / reloc-kind sequence / CFG counts / opcode-histogram cosine, all precomputed in .run/feat.*.jsonl), then instruction- count proximity, with a HARD PENALTY for opt-level mismatch (§116 — an -O2 example actively misleads an -O0 target). It surfaces the neighbour's HEADER COMMENT, which is the payload agents actually consumed. Explicitly NOT a remap claim: §168 law 1 measured cousins at 0/26. A neighbour is a worked example to READ; seed_ref remains the tool for the byte-identical case. Validated against ground truth: for main/func_80024054 (265k tokens, ended NEAR 32) the top three neighbours are func_8003A0E4, func_800242D0 and func_800241C0 -- all three MATCHED THIS SESSION, same TU, same call sequence, same reloc-kind sequence. src/800.c holds 657 matched functions and the card offered none of them. Bug fixed en route, and it is a repeat: the atlas writes addresses as hex STRINGS while corpus.Stub.addr is an int. T4's verifier already lost rows to exactly this string-vs-int mismatch (the R32 silent-no-op class). Normalised in _addr().
BFM-decomp
A matching decompilation of Brave Fencer Musashi (PlayStation, SLUS-00726, USA 1998) — the first public decompilation effort for this game.
What "matching" means
The goal is C source code that, compiled with the original-era toolchain (PsyQ 4.x / GCC 2.7.2-family + ASPSX via maspsx), produces a byte-for-byte identical SLUS_007.26 and, eventually, byte-identical overlay binaries. SHA1 checksums are the ground truth; "functionally equivalent" does not count.
No ROM content
This repository contains no game assets, no disassembly output, and no ROM-derived data — only source code, build configuration, symbol names/addresses, hashes, and documentation. To build or contribute you must provide your own dump of the game disc (4-track BIN/CUE, redump layout). See .gitignore for the firewall.
Project status
Latest (Phase 19, 2026-06-20): the project builds 136 binaries byte-identical from a clean tree (the EXE + the resident engine + all 134 location overlays);
make check-all→ 136/136. Fleet byte-identical-from-source is 58.0% (function-instance-weighted; see the PhaseEnds for the byte-weighted ~30% figure and what it includes). Shared engine functions are matched once inov_SC01_077and propagated ×134 viatools/dedup_propagate.py. (The narrative below is Phase-11/12-era; a full refresh is part of the public-flip prep.)
Gen1 (foundation) complete — the matching pipeline is proven end-to-end. make extract && make build && make check rebuilds SLUS_007.26 byte-for-byte identical (SHA1 143dbb89…) from C + assembly, reproducibly across many sessions.
- Compiler pinned by evidence:
gcc-2.7.2-psx -O2 -G0 -mips1 -mcpu=3000+maspsx --aspsx-version=2.56 --expand-div. - 52 functions hand-matched to byte-identical machine code — including the LZSS streaming decompressor — with a decomp-permuter + matching-cookbook "flywheel" to accelerate the next.
- 959 PsyQ SDK functions linked byte-identical (libcd, libgs, libgte, libspu/libsnd, libgpu, libc2, libmcrd, libapi/libcard, libetc) straight from the real PsyQ 4.0 libraries instead of re-decompiling them — bringing byte-identical-from-source coverage of the EXE to ~50%.
- File-loader / overlay system reverse-engineered, with the resident engine blob + location overlays' load addresses proven byte-identical against a live PCSX-Redux RAM dump.
About half the EXE is still INCLUDE_ASM stubs (correct bytes, not yet C), and the bulk of the game lives in compressed overlays inside the .CD archives — Gen2 (overlays & engine at scale) is underway:
- The build toolchain is binary-agnostic (one parameterized pipeline builds any binary), and the always-resident engine blob rebuilds byte-for-byte from source (SHA1
8e17e02f…) — the second binary reconstructed exactly, after the EXE — and is now 86% hand-matched C (123 / 146 functions, up from 0): its scripting turned out to be compiled-MIPS state/mode dispatch, not a bytecode VM, and the save-file + sound (SQV) formats are documented. The harvest used a reusable swarm-of-agents + bit-for-bit byte-gate method (a wrong match can't be accepted) —tools/harvest_verify.py+tools/match_one.py, which carry straight into the overlay phase. - A cross-binary deduplication pipeline is live: a Ghidra-free signer fingerprints all 134 location overlays, and the report finds ~9,000 byte-identical function groups shared across binaries (~28 MB of collapsible code) — a single engine function is byte-identical in all 134 overlays. This is "one match unlocks many": each engine match will be auto-credited across the overlay fleet.
Current phase and detailed progress live in phase-ends/ (newest PhaseEnd_*.md = current state); methodology, rules, and the full roadmap are in PROJECT_CONTEXT.md; environment setup in docs/SETUP.md.
This project is developed primarily by Claude Code driving Ghidra through an MCP server; see CLAUDE.md.
License
Private repository for now. AGPL-3.0 is planned at public release, modeled on sotn-decomp. tools/brave-CUE/ is CUE's BRAVE extractor (GPL, source included) and retains its own license.