Marvel vs. Capcom 2 — port and decompilation

Marvel vs. Capcom 2: New Age of Heroes, rebuilt from source:

Part	Where	State
The port: the game's own code on modern hardware, no emulator	port/	Playable end to end in the browser
PS2 decompilation (NTSC-U SLUS_204.86)	src/, config/, tools/	99.93% of code, 99.99% of data; rebuilds the retail ELF byte for byte
Arcade (NAOMI) decompilation	naomi/	In progress: 58.4% of the main image, 36.9% as verified C

No game data is in this repository. The port runs from your own disc.

The port

The port compiles the decompiled PS2 C for a 32-bit host and replaces only the console's hardware: graphics (WebGL2), sound (ADX streams and sound banks through Web Audio), controllers, memory card and disc. Everything the player does runs through the game's own code.

It plays by the arcade's rules. The PS2 build was made from the arcade program; where the two differ (timing, super-freeze order, flying-screen edges, Servbot hit-stop, float rounding and more), the port follows the arcade. The differences were found by comparing the two programs and confirmed by running the arcade ROM next to the port (ARCADE_DIFF.md).

There are no settings that make it worse. It always runs with:

• Zero added input lag: input is read the frame it happens, and run-ahead shows each press one frame sooner, ahead of the arcade cabinet. The display path is low latency too.
• Everything unlocked, no load times, sharp native-resolution output.
• Keyboard and gamepad for two players with full remapping (Xbox, PlayStation and Switch pads), and a touch overlay on phones.
• The Dreamcast's higher-rate sound effects, if you also give it your Dreamcast disc. The PS2's are 8 kHz; the Dreamcast's are 11–16 kHz.
• Saves that persist, and offline play once the disc is cached.

Play. Build the web version, or open a hosted copy, and choose your SLUS-20486 disc image once; it is cached in the browser. ?disc=URL and ?dcse=URL load the discs without the picker. Controls and building are in the player guide.

Verified against retail. An oracle runs the retail PS2 executable in an emulator and compares the port with it frame by frame: the whole game state, plus every sound command. 416 random fight seeds and 36 complete arcade runs (about 1.1 million frames, through Abyss to the ending) match exactly, and so do 410,208 sound commands (ORACLE_FUZZ.md). These runs switch the arcade rules off, so that retail PS2 is a fair reference.

Document	Contents
USER_GUIDE.md	Playing, controls, building, test switches
ARCADE_DIFF.md	PS2 vs arcade: what differs and what the port does
ORACLE_FUZZ.md	The retail comparison and its results
BOOT_NOTES.md	How the port runs the game's code; every fix, with its evidence
PS2_GRIPES.md	Known complaints about the PS2 version, and what the port does about each
RENDERER.md, AUDIO.md	The graphics and sound layers
PORT_PLAN.md	Phases and what is next (desktop builds)

PS2 decompilation

Every matched function is C compiled with a period toolchain (Metrowerks MWCC 2.4/3.0/3.0.3, SN GCC 2.95.2, EE GCC 2.96 or Sony EE GCC 2.9), and checked byte for byte against retail. The few routines that were hand-written assembly in the original (crt0, the exception handler, libvu0 kernels, the cache flush, newlib's r5900 string routines) are .S sources. The hybrid build links all of it and reproduces the retail ELF exactly (SHA-256 48ebf907…6f13d7).

Track	Progress
Code	99.93% (3,291,484 / 3,293,696 bytes; 20,181 / 20,678 functions)
Initialized data	99.99% (647,988 / 648,064 bytes)
Retail ELF rebuild	Byte-exact

The last 2,212 bytes of code are blocked by compiler behaviour that no available build reproduces; REMAINING.md gives the evidence for each. Setup, building and the matching rules are in DECOMP.md and AGENTS.md. CI checks the catalog, the build script and the tools. It cannot compile, because the compilers are not redistributable.

NAOMI decompilation

The arcade program, compiled with the original Hitachi SH C compiler and matched against the retail ROM. It is far from done, so the port runs the PS2 program. The arcade ROM is the reference for how the port plays. See naomi/README.md.

Layout

Path	Holds
port/	The port: host layer, renderer, audio, front ends, web shell, oracle tools
src/, config/, tools/, tests/	PS2 decompilation: C sources, symbol and match catalogs, build and verification tools
naomi/	NAOMI decompilation, self-contained
docs/	PS2 decompilation notes; docs/recovery/ holds the dated recovery records
build-inputs/, private/	Where you supply the retail image and compilers (ignored)

Legal

Disc images, ROMs, extracted assets, generated retail assembly, compilers and SDK files are not in this repository and must be supplied locally. The port contains no game data: it reads your own disc image at run time. This is a research project and is not affiliated with Capcom, Marvel, Sony, Sega or their licensors.