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PCEE2 - RetroBIOS
Type libretro
Classification Community forks
Source https://github.com/WizzardSK/pcee2-libretro
Upstream https://github.com/PCSX2/pcsx2
Version v2.7.523
Profiled 2026-09-03
Cores pcee2
Systems sony-playstation-2
BIOS directory pcsx2/bios/
Resources directory pcsx2/resources/
Technical notes

libretro port of current PCSX2, merged up to upstream 6db638dc (v2.7.523, pcee2-libretro/upstream.version); the build reports that version as library_version. Everything the port adds lives in pcee2-libretro/ and in the libretro renderer bridges; the BIOS, CDVD, patch and database code is upstream PCSX2.

InitializeConfig maps the PCSX2 folder layout under /pcsx2: AppRoot and DataRoot are that directory, Resources and UserResources are pcsx2/resources, Settings is pcsx2/inis, and EmuFolders::LoadConfig derives bios, memcards, cheats, patches, textures, gamesettings, cache, snaps, sstates, logs, covers, inputprofiles and videos from DataRoot (pcee2-libretro/Libretro.cpp:414-428, pcsx2/Pcsx2Config.cpp:2319-2336). A standalone PCSX2.ini dropped in pcsx2/inis contributes nine emulation sections as the baseline (Libretro.cpp:504-535); the core options and the port overrides apply on top.

BIOS detection is filename-agnostic. The core option pcsx2_bios lists every file of pcsx2/bios that IsBIOS accepts: a romdir whose RESET entry is followed by a readable ROMVER, whose fifth character gives the zone (Japan, USA, Europe, Asia, China, T10K, COH-H, Test, Free). With the option on auto, SettingsOverride selects the first accepted file (Libretro.cpp:578-618, pcsx2/ps2/BiosTools.cpp:80-197, 284-294). When no BIOS is configured or the configured name is missing, LoadBIOS falls back to FindBiosImage, which also filters on size between 4 and 8 MB (BiosTools.cpp:258-282, 317-369). The image is read into the 4 MB ROM region; a file shorter than 2465792 bytes turns off the OSDSys parameter HLE. No hash is matched. Booting with no content starts the BIOS (Libretro.cpp:2090-2096).

Companions derive from the selected image: rom1 and rom2 are tried as the full name plus extension, then with the extension replaced, and are skipped when absent; the nvm is read at the replaced extension and rebuilt with region and language defaults when missing or blank; the mec is written back as 0x00020603 when it cannot be read (BiosTools.cpp:214-241, 366-367, pcsx2/CDVD/CDVD.cpp:136-205).

The shaders, four interface fonts and GameIndex.yaml are built into the core (cmake/EmbedResources.cmake:19-31, pcsx2/CMakeLists.txt:1137-1157) and win over the copies on disk unless PCEE2_EXTERNAL_RESOURCES is set in the environment (pcsx2/EmbeddedResources.cpp:8-12, pcsx2/GS/Renderers/Common/GSDevice.cpp:372-387, pcsx2/ImGui/ImGuiManager.cpp:470-492, pcsx2/GameDatabase.cpp:1021-1050, Libretro.cpp:451-473). A missing resources directory is a warning, not a failure (Libretro.cpp:433-442). What the directory still supplies to this build is patches.zip. RedumpDatabase.yaml is read only by the Qt game summary (pcsx2/GameDatabase.cpp:1197-1210 has no caller in the core), game_controller_db.txt only by the SDL input source the port disables (Libretro.cpp:561-562, pcsx2/Input/SDLInputSource.cpp:701-706), the achievement sounds only with achievements enabled, which no core option or adopted ini section does (pcsx2/Achievements.cpp:943-951), and fullscreenui/no-save.png only by the save state selector, whose hotkeys the port clears (Libretro.cpp:564, pcsx2/ImGui/ImGuiOverlays.cpp:1461-1462). The port supplies Roboto alone to ImGui, so no emoji font is read.

Per-game user files keep their PCSX2 locations under /pcsx2: cheats and patches as .pnach (pcsx2/Patch.cpp:333-363), gamesettings/.ini (pcsx2/VMManager.cpp:830-833), textures//replacements (pcsx2/GS/Renderers/HW/GSTextureReplacements.cpp:262-264), memcards/*.ps2, which the core creates and lists in the memory card options (Libretro.cpp:620-640). The DEV9 HDD image is named in the ini and created on demand.

7 files | 1 required, 6 optional | 7 in repo, 0 missing | 3 with HLE fallback Categories: 6 BIOS, 1 game data

<bios>.bin required in repo
PS2 BIOS image

<bios>.rom1 optional in repo
DVD player ROM

<bios>.rom2 optional in repo
Chinese ROM extension

<bios>.nvm optional in repo HLE fallback
Console NVRAM (region parameters, language, iLink ID, OSD settings)

<bios>.mec optional in repo HLE fallback
Mechacon version, one u32

patches.zip optional in repo game_data bundled
Built-in game patch archive (pnach per serial and CRC)

  • Path: pcsx2/resources/patches.zip
  • Source: pcsx2/Patch.cpp:117, pcsx2/Patch.cpp:289-317, pcsx2/Patch.cpp:365-405
  • Opened read only from the resources directory when a game's patches are enumerated and searched for _.pnach, then .pnach. Files in the patches folder take precedence. A failure to open is reported once on screen. Not part of the PCSX2 source tree: PCSX2 builds fetch it from the pcsx2_patches releases, a rolling asset rebuilt on every patch commit.

eeprom.dat optional in repo HLE fallback
DEV9 network adapter EEPROM

Data directories

  • pcsx2-resources >pcsx2/resources

Generated on 2026-09-14T09:03:10Z