Resident Evil 4 (GameCube) — decompilation
A complete, byte-identical decompilation of Resident Evil 4 for the Nintendo GameCube: the
G4BE08 debug build (the "Nov 25 2004" prototype, both discs), whose Bio4.sym files name every
function. Building the repository reproduces main.dol and all 114 REL overlays exactly
(config/G4BE08/build.sha1, checked on every build).
|
|
| Objects |
1083 (675 in the DOL, 408 across the 114 RELs), all byte-identical; 23289 function symbols (14587 distinct names; template and inline copies repeat per module) |
| Source |
~571k lines of C/C++ (src/: 635 .cpp, 380 .c), ~43k lines in 417 headers (include/); no assembly files |
| Game code |
SN Systems ProDG 3.9.3 — GCC 2.95.3 "SN BUILD v1.79", built natively from SN's GPL source drop |
CRI middleware (src/lib/adx_*, sfd_*, mpv_*, …) |
Metrowerks CodeWarrior 2.4.7 (GC/2.7), the compiler CRI shipped the libraries with |
Nintendo SDK (src/lib/OS*, GX*, …) |
Metrowerks CodeWarrior GC/1.2.5n, sources from dolsdk2004 |
The repository contains no game assets and no code or data copied from the discs. You need your
own images of the debug discs to build (disc 1 for main.dol and most RELs, disc 2 for the four
island-stage RELs); the original files are read from them at configure time.
Building
Linux, Python 3, ninja. Compilers and tools (decomp-toolkit, objdiff,
wibo, the CodeWarrior builds) are downloaded by the first configure run, except the native SN GCC:
# 1. the native cc1/cc1plus (once): needs SN's GPL source drop, see tools/sn-gcc/build.sh
SN_GCC_SRC=/path/to/NGC_GNU_SRC/NGC tools/sn-gcc/build.sh
# 2. your disc images (disc 1: main.dol + 110 RELs; disc 2: the four island-stage RELs st3_0..st3_3)
cp re4_debug_disc1.iso re4_debug_disc2.gcm orig/G4BE08/
# 3. build and verify
python3 configure.py && ninja
ninja ends with the progress report (100% matched and linked for the DOL and the REL modules);
build/tools/dtk shasum -c config/G4BE08/build.sha1 prints 115 OK lines. To work on a unit, python3 tools/bytecmp.py game/foo compares its object with
the original word by word and python3 tools/fdiff.py game/foo <symbol> shows one function.
Layout
src/game/ — the game (C++; a few newlib C units). src/em*/ enemies, src/wep*/ weapons,
src/pl*/ player characters, src/st*/ rooms (one REL per room), src/t_*/, src/Tools/,
src/tools/ the in-game debug editors, src/Sscrn/ the sub-screens, src/lib/ SDK, CRI and runtime.include/ — headers, including the reconstructed struct layouts.config/G4BE08/ — unit lists (objects.py, modules.py), symbols.txt, splits.txt, linker
scripts, per-module REL data (modules/<mod>/), build.sha1.tools/ — build generator (project.py), the ProDG driver (ngccc.py), REL rebuild (make_rel.py,
link_rel.py), the compare tools, sn-gcc/ (native compiler build), research/ (compiler-analysis kit),
motion_export.py + motion/ (animation export to glTF/BVH, evaluated with the game's own code and
verified against the game running in Dolphin).docs/overview.md — how the engine is put together: a reading guide to src/ by subsystem.docs/matching.md — how the matching was done: compiler provenance, the catalogue of compiler
mechanisms and the source shapes that reproduce them, rules of thumb for both compilers.
docs/unit-notes.md — per-unit notes. docs/research/ — the pass-by-pass research log.
What "matching" means here
Every unit compiles to the original bytes with the original compilers. Where the compiler needed a
particular source shape to reproduce a register choice or a schedule and no natural spelling was
found, the construct is marked with a // COMPILER-DIFF: comment (578 of them: dead tests, empty
asm("") launders and anchors, register T x asm("rN") pins, padding statements). None of them
emits an instruction: python3 tools/asmcheck.py --all compiles every GCC unit with its asm templates
marked and lists the instructions that came from a template — the only hits are the hardware kernels
below (TOTAL 231; the eight asm-bodied units are reported on their own line and kept out of that
number). An earlier state of this tree had ~100 hand-placed instructions (asm("li %0,0"),
asm("lis/addi"), asm("mr")) in the game code and ~100 register-pinning asm { } blocks in the CRI
libraries; they were replaced by C on 2026-09-17 (docs/research/compiler.md, section "Asm-removal pass", records the recipe
and the compiler mechanism per site). Each tag's mechanism is documented in docs/matching.md and
docs/research/.
Assembly that remains, all of it code the original authors also wrote in assembly because their
compilers had no other way to express it:
- GCC 2.95 game code: paired-single kernels (
SINF/COSF/RSQRT/LIMIT_ANGLE in math_sub, the
matrix kernels in trans, shape, dbmodule, quantised psq_l in Espgen42/espgen45), the
GQR setup in main/scheduler, and the libsn sndvd exception handler.
- MWCC CRI libraries: the paired-single / cache / SPR kernels (
mpv_umc, mpv_mc, dct_fsri,
cftyp422_ppc, mpv_lib), the SDK's mtx/vec/quat/GX intrinsics, and one register-steering
block in dct_ac (DCT_AcInit: the vendor's compiler build pooled .bss but not the function's
8-byte literals; ours pools both). Codeless asm { mr r11, x; mr x, r11 } pins (both moves are
deleted by the allocator; they narrow the colour set by one register) and asm { mr v, v } self
copies (an opaque second definition) remain in 28 places.
- Eight asm-bodied units: crt0 (
__start), eabi, SN's tealeaf/fileserver/ppcdown/proview
(src/lib/<name>.c), and Capcom's memset_2 and yz2asm (src/game/<name>.cpp). The originals
were assembly (SN's libsn/crt0 objects and Capcom's own asm; no compiler idiom in the bytes), so
each is a C file whose functions are whole-function top-level asm() bodies in GAS syntax
(.globl/.type/label/.size, local .L_ labels, .4byte/.float/.skip data), compiled by
the same ProDG driver as the rest (include/asm_regs.h supplies the r3/f1/GQR0 names as
.set constants; NgcAs takes bare numbers). tools/asmcheck.py lists them as asm-bodied.
Naming
Function names are Capcom's, from the debug build's Bio4.sym files; they are C++-mangled, which is
why the game code is C++ and the SDK, CRI and newlib units are C. File names and unit boundaries come
from the D:/Bio4/Prog/<file>.cpp strings the asserts left in the binaries. Struct and field names are
of three kinds: the vendor's, from the PS2 debug build's type information (matched to the GameCube
layouts by tools/ps2sym.py); ours, named from usage and marked as such; and placeholders xNN
(offset in hex, meaning unknown). Vendor names keep the vendor's spelling, so the tree mixes
conventions on purpose. Constants are the PS2 build's enums, imported as declared, and the pG flag
bits are read through the XxxFlagChk/On/Off macros of include/global.h with the PS2 bit names.
#line directives reproduce the vendor's line numbers in the assert strings.
docs/naming.md has the full account and the counts.
Contributing
CONTRIBUTING.md: build, the three verification checks, the rules (bytes never change, no
instruction-emitting asm, naming), and how to propose a rename with evidence.
Legal
The reconstructed game and SDK source is the intellectual property of its respective owners
(Capcom, Nintendo, CRI Middleware) and is published for research and preservation only. The build
scripts, tools and documentation written for this project are released under CC0 (LICENSE).
对 GameCube 版《生化危机 4》的完整逐字节还原的反编译——即 G4BE08 调试版，包含两张光盘——以可读的 C/C++ 代码重建，并能在编译后得到和原版完全一致的程序文件。