geolith-libretro
----------------
Geolith is a highly accurate emulator for the Neo Geo AES and MVS.

This emulator supports TerraOnion's .NEO file format only.

BIOS files from a recent MAME set are required:
 - aes.zip for Neo Geo AES (Home Console)
 - neogeo.zip for Neo Geo MVS (Arcade) and Unibios

This is the libretro port of the Geolith emulator, whose upstream repository
lives at: https://gitlab.com/jgemu/geolith

ROM Set Support
---------------
This emulator was written against ROMs with checksums equal to those of the
LunaGarlic set. It is recommended to use these checksums to verify your
legally obtained dumps are correct. Check the included "rename-neo.sh" for
more information.

Input Devices
-------------
geolith-libretro supports the following input devices:

Neo Geo Joystick
Multiplayer Extension Board (NEO-FTC1B, 4 Player)
V-Liner

Compatibility
-------------
Geolith is compatible with 100% of the commercially released Neo Geo AES and
MVS libraries. Most games work in both modes, but some require MVS mode.

All bootlegs and hacks from the MAME set are compatible, the majority of which
require being run in MVS mode. Other bootlegs and hacks not in the MAME set may
be compatible if correctly converted to the .NEO format.

Some MVS releases will exhibit glitches when run on an AES BIOS. Home Console
releases are preferred when running in AES mode.

Some early prototypes are not currently possible to emulate, pending new dumps
or new information:
  Stakes Winner (early development board) - Missing data from SRAM chip

Dedicated JAMMA PCB and Neo Geo CD systems are not currently supported.
PAL mode is not currently supported.

The special inputs for Irritating Maze are not yet supported. It is possible to
play Irritating Maze using the Universe BIOS with a cheat enabled for joystick
controls.

Accuracy/Caveats
----------------
Geolith's CPUs are emulated at instruction level granularity and are very
tightly synced to each other as well as the LSPC (video) and YM2610 (sound).
Video related events are timed with a "best effort" approach based on available
documentation, with future original hardware research on the agenda. The longer
term goal is to have completely cycle accurate video rendering, but for now,
things are emulated accurately enough that all games are fully playable with
only very minor differences from real hardware, and no known major bugs.

Contributing
------------
Any contributions should respect the coding style and the direction and goals
of this emulator. All code should be placed under a permissive license (BSD,
MIT, etc). Changes made for portability or speed should be as generic as
possible, and any preprocessor directives for platform-specific code should be
avoided at all costs in the interest of keeping the emulator core clean,
maintainable, and free of regressions.

Copyright
---------
Geolith (BSD-3-Clause)
  Copyright (c) 2022-2024 Rupert Carmichael
  See LICENSE

Jolly Good Z80 (MIT)
  Copyright (c) 2019 Nicolas Allemand
  Copyright (c) 2020-2022 Rupert Carmichael
  Copyright (c) 2022 rofl0r
  See src/z80/LICENSE

miniz (MIT)
  Copyright 2013-2014 RAD Game Tools and Valve Software
  Copyright 2010-2014 Rich Geldreich and Tenacious Software LLC
  See deps/miniz/miniz.c (https://github.com/richgel999/miniz)

Musashi (MIT)
  Copyright (c) 1998-2019 Karl Stenerud
  See src/m68k/readme.txt (https://github.com/kstenerud/Musashi)

Speex Resampler (BSD-3-Clause)
  Copyright (c) 2003, 2007, 2008 Xiph.org Foundation
  See source files in deps/speex/ (https://github.com/xiph/speexdsp)

YMFM-C (BSD-3-Clause)
  Copyright (c) 2021 Aaron Giles
  Copyright (c) 2022 Rupert Carmichael
  See source files in src/ymfm

Extra Credits
-------------
This emulator could not have been written without the hard work and research
done by the FinalBurn Neo project, MAME, GnGeo, and the NeoGeo Development Wiki.