parasite-eve-decomp-port

parasite-eve-decomp-port

Parasite Eve decomp and port: a matching decompilation of Parasite Eve (PlayStation, USA, SLUS-00662) and a native Linux port that runs the decompiled game code.

You need your own disc. This repository contains no game data, no BIOS and no Sony SDK code. The port reads everything from your own copy of Parasite Eve. See NOTICE.md.

Just want to play? Jump to How to play.

New (2026-10-08): native-only build. Release native-only-ab6de50b runs only native C: no MIPS interpreter and no CPU emulation in the game. A function that isn't ported yet stops the game with a CPU_BOUNDARY/REFUSED message instead of being emulated (rooms included: they no longer skip missing code silently). On a real disc image it plays Day 1 through to the opening of Day 2, and 377 of 402 Day 2 room slots ran clean in a warp sweep. It is untested by hand past Day 1 and has not been played on real hardware yet. What works and what doesn't: docs/port/NATIVE_ONLY_STATUS.md. It supersedes native-only-328511c8. The earlier native-only-2918a7f0 stops about 12 minutes into Day 1; don't use it. The hardware-tested Day 1 build is still r5.

About this project

This is a passion project. I'm working hard on it, but it's made for fun and for everyone's enjoyment — free, non-commercial, and made by a fan. If you enjoy it, that's the whole point.

How to play

This is a native Linux build of Parasite Eve, not an emulator. You need your own copy of the game; nothing from the game is included. No BIOS is needed. Day 1 plays from start to finish.

1. Download

From the r5 release, download parasite-eve-day1-day1-r5-16a267b1-linux-x64.tar.gz. You can also download SHA256SUMS if you want to check the file.

What is in the r5 build. The r5 binary is compiled from the full development tree, so it contains two things this repository's source leaves out:

• Psy-Q SDK-derived code: about 445 functions that translate Sony's Psy-Q libraries (graphics, CD, pad, sound, GTE and others).
• khasinski's upstream code: credited, and not under this repository's MIT license (see UPSTREAM_FILES.md).

It includes no game assets, apart from the PlayStation SPU's 40-byte sound-interpolation table. All of this is being replaced by the project's own code in later releases (a Psy-Q-free port layer).

2. Install

Unpack it into ~/Games:

mkdir -p ~/Games
tar xzf ~/Downloads/parasite-eve-day1-day1-r5-16a267b1-linux-x64.tar.gz -C ~/Games

That gives you ~/Games/parasite-eve-day1-day1-r5-16a267b1/, with the launcher parasite-eve inside.

3. Your disc

You need Parasite Eve (USA) Disc 1 as a raw BIN/CUE image. This is the "Redump" kind: one .bin of 495,531,120 bytes, next to its .cue. An .iso or .chd does not work directly.

• Ripped with a disc tool to BIN/CUE: use the .bin as it is.
• You have a .chd: convert it with chdman extractcd -i "Parasite Eve (USA) (Disc 1).chd" -o "Parasite Eve (USA) (Disc 1).cue" -ob "Parasite Eve (USA) (Disc 1).bin". chdman comes with MAME. On Bazzite or Steam Deck, install mame-tools in a distrobox.

Put the .bin and .cue in a folder of their own:

~/Games/parasite-eve/disc/Parasite Eve (USA) (Disc 1).bin
~/Games/parasite-eve/disc/Parasite Eve (USA) (Disc 1).cue

Nothing needs to be extracted. The port reads the image directly and checks it on start.

4. Run it

~/Games/parasite-eve-day1-day1-r5-16a267b1/parasite-eve ~/Games/parasite-eve/disc

You can pass the folder, the .bin or the .cue. It starts fullscreen. For a window instead:

PE_WINDOWED=1 ~/Games/parasite-eve-day1-day1-r5-16a267b1/parasite-eve ~/Games/parasite-eve/disc

To run it without typing the disc path every time, save the path once:

mkdir -p ~/.config/parasite-eve-port
echo "disc1=$HOME/Games/parasite-eve/disc" > ~/.config/parasite-eve-port/config

After that, ~/Games/parasite-eve-day1-day1-r5-16a267b1/parasite-eve alone is enough, and you can double-click it in a file manager.

5. Steam Deck / Bazzite Game Mode

1. In Desktop Mode, save the disc path once (the config step above).
2. In Steam, choose Games → Add a Non-Steam Game → Browse. Pick ~/Games/parasite-eve-day1-day1-r5-16a267b1/parasite-eve.
3. Switch to Game Mode and start it from your library. No launch options are needed.
4. Controller: the built-in controls work as a standard Xbox-style gamepad. Use Steam's default "Gamepad" layout.

Controls

PlayStation	Gamepad (Xbox labels)	Keyboard
D-pad / move	D-pad or left stick	Arrow keys
Cross (confirm, act, fire)	A	Enter, Space, Z or X
Circle (cancel)	B	C
Square	X	S
Triangle (menu)	Y	V
L1 / R1	LB / RB	Q / E
L2 / R2	LT / RT	1 / 3
Select	Back / View	Tab
Start	Start / Menu	P
Fast-forward on/off	L3 (click left stick)	F6
Fast-forward while held	R3 (click right stick)	—
Quit	—	Esc

Keyboard and controllers work at the same time. You can plug a controller in or remove it while the game runs.

Dev menu (cheats; off unless you press them): F1 shows the help. The other keys are F2 god mode, F3 infinite ammo and full PE, F4 win the current battle, F5 key items, F6 fast-forward and F7 fast-forward speed. F8 opens the warp menu: Up/Down chooses, Enter warps, F8 closes it. Use warps while walking around in the field. "CHEATS" shows in the corner while any cheat is on.

Saves

Memory card saves go to ~/.local/share/parasite-eve-port/memcard1.mcd. They survive updates, because the install folder is never written to.

Troubleshooting

• Nothing happens when I double-click it. The launcher didn't find your disc. Run it from a terminal with the disc path (step 4) and read the message.
• "not a raw 2352-byte/sector BIN". You gave it an .iso or a converted image. Use the .bin from a BIN/CUE dump (or convert the .chd, step 3).
• The disc is rejected at start. The port checks for USA Disc 1 (SLUS-00662). A different region, Disc 2, or a modified image is refused, with a message saying why.
• "no X display". Run it from a desktop session or Game Mode. Wayland desktops provide one through XWayland.
• GLIBC_2.34' not found. Your Linux is too old. The build needs glibc 2.34 or newer: a 2021-or-later distribution, including SteamOS 3 and Bazzite.
• No sound. Sound needs libpulse-simple.so.0, which PipeWire provides on current distributions. If sound crackles, try PE_AUDIO_LATENCY_MS=150.
• The controller does nothing. Check that ls -l /dev/input/js* lists a device your user can read. If Square and Triangle are swapped, set PE_PAD_SWAP_XY=1.
• Logs: every run writes ~/.local/state/parasite-eve-port/logs/run-<time>.log (the last 10 are kept). Include the newest one, with the time and room and a screenshot, when you report a bug.

Known issues in r5:

• Using some equipment or tool items from the field menu may stop the game. Healing items are fine.
• Loading screens are shorter than on a real PlayStation.
• Aya's gun model may be missing when she readies it.

FAQ

• Do I need a PlayStation BIOS? No.
• Is the game included? No. There are no game files, music or movies. You must own the disc, and the port reads your copy.
• How far does it go? Day 1 plays from start to finish: the opera, Carnegie Hall, the sewers and the alligator boss, with the movies. Days 2 to 6 and Disc 2 are in progress.
• Windows? Not yet. This release is Linux x86-64 only.

What is here

• src/: the matching decompilation. This repository has 1,772 EXE functions in C that compile back to the retail bytes, plus the overlay functions. The development tree has 2,252 matched EXE functions. The difference is the Psy-Q SDK functions and two functions with retail tables, which are split from your disc as assembly instead.
• pc_port/: the native port, including the host layer (window, input, audio, saves), the disc checks, the opt-in cheats, and its tests.
• configs/: splat and symbol configuration (addresses and names only).
• tools/, scripts/, dev/: the analysis tools, including the retail-data and Psy-Q guards, the build scripts and the build container.
• docs/: project, port and divergence documentation.

Build from source

The matching build is turnkey: from a clean clone and your own disc, it rebuilds the retail executable byte for byte (SHA-1 452fb033f2eaa4b18aa20a5bca60b8125af3a37b). Every retail byte that isn't published here is split from your disc at build time. That covers the assembly, the data, and the Psy-Q SDK functions whose source isn't published. You need git and Docker.

git clone https://github.com/Blizz127/parasite-eve-decomp-port.git
cd parasite-eve-decomp-port

# Your disc: the Redump BIN/CUE of Disc 1, copied (or linked) here
mkdir -p "rom/image/Parasite Eve (USA) (Disc 1)"
cp ~/Games/parasite-eve/disc/"Parasite Eve (USA) (Disc 1)".{bin,cue} "rom/image/Parasite Eve (USA) (Disc 1)/"

# The build container (Debian with a mipsel cross toolchain)
docker build -t parasite-eve-mipsel:trixie -f dev/mipsel/Dockerfile .

# Toolchain setup, extract, split, build and verify
docker run --rm -u "$(id -u):$(id -g)" -e HOME=/tmp -v "$PWD":/workspace \
  parasite-eve-mipsel:trixie bash -c '
    scripts/setup_env.sh && scripts/setup_era.sh &&
    export PATH=/workspace/.venv/bin:$PATH &&
    scripts/extract_us.sh 1 && scripts/split_us.sh &&
    scripts/build_us.sh && scripts/verify_us.sh'

• setup_env.sh installs the pinned splat into .venv/.
• setup_era.sh downloads the era compilers (decompals/old-gcc) and maspsx at a pinned commit, and keeps this repo's patched maspsx files.
• The build ends with Compare: EXACT SHA-1 452fb033…, and verify_us.sh prints VERIFY_US=PASS.

Everything the build writes (build/, asm/, assets/) is git-ignored, and your disc is only read.

The native port (pc_port/) can't be built from this repository yet. The files that still translate Psy-Q SDK code are being replaced by the project's own port layer, and they are not published. The prebuilt release is the way to play until then.

Status

Day 1 is playable from start to finish on the port (r5), and movies play in real time. Since 2026-10-07 the port is native only: the game binary has no MIPS interpreter or CPU emulation, and the sound driver runs as native C. The native-only build plays Day 1 to the opening of Day 2 on a real disc image; it has not been played on real hardware yet. The calls that still stop it are listed in docs/port/NATIVE_ONLY_STATUS.md. Every known difference from the PlayStation original is logged in docs/port/KNOWN_DIVERGENCES.md.

Credits and license

• Credits: CREDITS.md, covering khasinski's decompilation, the tools and the libraries. The imported files are listed in UPSTREAM_FILES.md.
• License: LICENSE (MIT), for this project's original work only.
• Legal notice and disclaimer: NOTICE.md. Parasite Eve is © Square Enix. This project is not affiliated with or endorsed by Square Enix.