Drew T 8d40d55c7a docs(phase-30): SS130 — an INCREMENTAL build reported BYTE-IDENTICAL for a change the CLEAN build cannot LINK
I reported func_8013B83C + func_8013BD74 as "BOTH BANKED - BYTE-IDENTICAL". That was
WRONG. My in-loop gate ran `make extract && make build` without `make clean`, and it gave
a FALSE PASS. The clean rebuild does not link at all:

    ov_SC01_077_o0.c:(.text+0x10f8): undefined reference to `$L105'
    ov_SC01_077_jr_801588CC.o: undefined reference to `func_8013C938'

- the first is a local label from the C-emitted jump table;
- the second is a PREVIOUSLY-MATCHED cluster fn going undefined (the incremental build
  reused objects that still satisfied it).

Reverted; R22 140/140; nothing lost, nothing was committed.

SS42b named the stale-object trap for a FALSE FAIL. This is its MIRROR: a FALSE PASS, on a
change that is not even linkable — false in the most convincing direction possible, a green
SHA. Anything touching config/ (carve, resegment, split) must be gated by a full
clean-fleet R22 before it is BELIEVED, let alone reported.

THREE WRONG CLASSIFICATIONS ON THIS PAIR, all corrected in the ledger:
  CC1-FAIL-UNREAD      -> it has no compile error at all
  JTBL-PAD-SPEC-DRIFT  -> I had carved ONE fn of a TWO-table span; carving both gives
                          pad spec [0,4,4] and the filter is satisfied
  "both banked"        -> the false pass above
Real class: JR-PAIR-IN-ONE-O0-OBJECT. Both bodies ARE byte-correct (match_one --o0 and
rtu_match --o0 both MATCH, 272 / 198 ins); the blocker is integrating TWO jr fns into ONE
-O0 object. Untested escape: SS81 step 1, isolate one into its own code subseg so each
object owns exactly one table.

Also records the diagnostic ladder that found it: diff the two BINARIES and bucket each
differing byte against the function's own vram range. 3,749 of 3,791 diffs were OUTSIDE the
function, first diff near the overlay START, image 57 bytes LONGER - the SS8 signature of
.rodata floating to the front. That fingerprint separates a codegen residual from a layout
effect in one build, and it is what finally redirected three wrong guesses.
2026-07-31 18:47:00 -06:00
2026-06-10 22:02:07 -06:00
2026-06-10 22:02:07 -06:00

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 in ov_SC01_077 and propagated ×134 via tools/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.

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