Drew T 109ce6a2c3 feat(phase-29): BEHEMOTH #6 func_8017C730 BANKED (1,061 ins) + §82 two source-shape oracles
- CRACKED at xHigh and VERIFIED INDEPENDENTLY: match_one MATCH (1061 ins); agent re-matched 3x
  from clean runs (100% register-masked AND register-kept, all 10 regions, frame 0x270 exact).
  §81 carve chain clean first try: jr_isolate_all --only -> byte-identical cacaf7c2 -> jtbl_carve
  (43-piece set) -> byte-identical -> bank -> R22 clean-fleet 140/140, tools-health OK.
  instr 80.6%; distinct-code 3,844,100 -> 3,845,161.
- WHAT IT IS: the matched base func_8017CA80 + camera height-band cull + distance-driven CLUT
  fade. func_8004974C (TransposeMatrix) sits in a 36-ins prologue deriving a Y band; the
  part-level `lim >= g.otz` cull is GONE; flat arms gain an `sz < lim` near-plane cull. The
  base+one-extra-callee fingerprint predicted this exactly.
- §82 ORACLE 1 -- A DUPLICATED `addiu $aN,$sp,K` ACROSS A `jal` MEANS THE BLOCK WAS INLINED.
  `&X` on any non-first local always creates a pseudo and CSE always merges two of them
  (expr.c:6260 ADDR_EXPR -> force_operand(..., NULL); exception: virtual-stack-vars offset 0).
  So the same stack address re-materialised at two sites separated by a jal means CSE was
  PREVENTED from merging => not the same function body. 17 non-inline spellings failed; a
  `static inline` helper reproduced the prologue BYTE-FOR-BYTE first try. Reusable probe: scan
  the ~1,200 built objects for that signature in NON-INCLUDE_ASM functions.
- §82 ORACLE 2 -- SCALAR vs AGGREGATE DECIDES *WHEN* A STACK SLOT IS ALLOCATED: lazily at first
  `&` for a scalar, AT DECLARATION for an aggregate. Six GTE result words had to be six separate
  longs, not a struct, or they don't land after the inlined helper's temps and the frame isn't
  0x270. Second-order: it also flips MEM_IN_STRUCT_P (§30's /s) -- with one word a fixed-address
  scalar, ((PolyF3*)pkt)->rgbc stops aliasing it, so a store needed respelling to keep the
  target's nop. A scalar-vs-struct choice is simultaneously a frame-layout AND an aliasing
  decision.
- BANKING FOOTNOTE (§75a class A): first bank rejected `conflicting types for ApplyMatrixSV` --
  draft (MATRIX2*, SVECTOR2*, SVECTOR2*) vs the TU/fleet canon (void*, void*, void*), 2,286 of
  2,835 sites. Conforming the decl is byte-neutral and banked first try. On a jr function expect
  BOTH gates to speak: the carve chain answers the jump table, §75a answers the declarations.
- Also reproduced: §78 (reuse a busy variable), §80(i) (a lever went -8 -> exactly neutral as the
  base moved), §72 (a register pin made it worse).
- AGENT'S OWN CAVEAT, recorded not hidden: one zero-byte __asm__ keeps a vestigial `mnc = hmid`
  alive that flow.c would delete (costing 10 ins + the 0x130 spill slot). Emits nothing, compile
  is 1061 exact, but it is a documented stand-in -- 12 natural spellings measured, all DCE'd.
2026-07-25 23:24:11 -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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