feat: add 10 emulator profiles (119-series batch 2)

freeintv_ts_overlay (same BIOS as FreeIntv), bnes (NES, no BIOS), clownmdemu (Mega Drive, open-source MCD boot ROM embedded), m2000 (Philips P2000T, all embedded), mesen (NES, FDS + StudyBox BIOS), race (NGP, HLE with disabled BIOS loader), vemulator (VMU, HLE only), gw (Game & Watch, Lua simulator), pd777 (Cassette Vision, no BIOS), play (PS2, full HLE, LoadBIOS commented out) 115 total profiles.
2026-04-13 12:22:33 -05:00 · 2026-03-17 20:15:28 +01:00
parent a77477cbe8
commit ebc8e4413f
10 changed files with 618 additions and 0 deletions
--- a/emulators/bnes.yml
+++ b/emulators/bnes.yml
@@ -0,0 +1,59 @@
+emulator: bnes
+type: libretro
+source: "https://github.com/libretro/bnes-libretro"
+cores:
+  - bnes
+systems:
+  - nes
+
+notes: |
+  bnes is a NES emulator based on byuu's bNES/higan v083 NES module, ported
+  to libretro by Ryphecha. It is a lightweight, accuracy-focused NES core.
+
+  The core loads cartridge data entirely through retro_load_game with
+  need_fullpath=false (libretro.cpp:129). ROM data is passed as a memory
+  buffer and parsed by Cartridge::load (cartridge.cpp:18-31), which detects
+  iNES headers (16-byte offset) and delegates to Board::load for mapper setup.
+
+  The PPU generates its palette from a hardcoded color table in libretro.cpp
+  (lines 20-37) with emphasis factor tables. No external palette file is loaded.
+
+  System::init (system.cpp:62-66) only sets up the interface pointer and
+  default input devices. No system ROM, BIOS, or firmware is loaded at any
+  stage of initialization or cartridge loading.
+
+  The core does not call RETRO_ENVIRONMENT_GET_SYSTEM_DIRECTORY and has no
+  file I/O for BIOS or firmware. FDS (Famicom Disk System) is not supported,
+  so disksys.rom is not needed.
+
+  No external BIOS or firmware files are needed.
+
+files: []
+
+analysis:
+  bios_search:
+    retro_load_game: "libretro.cpp:181-211 - loads cartridge data only, no BIOS"
+    cartridge_load: "cartridge.cpp:18-31 - parses iNES header + ROM data"
+    system_init: "system.cpp:62-66 - sets interface pointer, no ROM loading"
+    system_power: "system.cpp:43-50 - powers subsystems, no file I/O"
+    interface_init: "interface.cpp:17-20 - stores derived pointer, calls system.init"
+  supported_mappers:
+    - NROM
+    - SxROM (MMC1)
+    - UxROM
+    - CNROM
+    - TxROM (MMC3)
+    - ExROM (MMC5)
+    - AxROM
+    - BnROM
+    - GxROM
+    - PxROM (MMC4)
+    - FxROM (MMC4)
+    - Bandai FCG
+    - Konami VRC4
+    - Konami VRC6
+    - Konami VRC7
+    - Sunsoft 5B
+  fds_support: false
+  filesystem_access: false
+  system_directory_used: false
--- a/emulators/clownmdemu.yml
+++ b/emulators/clownmdemu.yml
@@ -0,0 +1,61 @@
+emulator: ClownMDEmu
+type: libretro
+source: "https://github.com/libretro/clownmdemu-libretro"
+cores:
+  - clownmdemu
+systems:
+  - sega-megadrive
+  - sega-megacd
+
+notes: |
+  ClownMDEmu is a Sega Mega Drive/Genesis and Mega CD emulator by Clownacy.
+  Supports cartridge (bin/md/gen) and CD (cue/iso/chd) formats, plus a
+  subsystem for cartridge+CD combo (Mega CD Mode 1).
+
+  The core has NO external BIOS file requirements. firmware_count = 0 in the
+  libretro .info file confirms this.
+
+  Mega CD boot ROM: a custom open-source replacement boot ROM is compiled
+  directly into the binary as a 16384-entry uint16 array
+  (mega-cd-boot-rom.c included into bus-main-m68k.c:19-21). Source at
+  https://github.com/Clownacy/clownmdemu-mcd-boot. No external CD BIOS
+  files (bios_CD_E.bin, bios_CD_U.bin, bios_CD_J.bin) are needed or loaded.
+
+  TMSS (Trademark Security System): not implemented at all. No TMSS ROM is
+  loaded or checked. The core boots games directly without the "Produced by
+  or under license from Sega" screen.
+
+  The system directory (RETRO_ENVIRONMENT_GET_SYSTEM_DIRECTORY) is only used
+  as a fallback path for Backup RAM (BuRAM) save files, not for BIOS loading.
+
+  CD add-on can be enabled for cartridge games via the "clownmdemu_cd_addon"
+  core option to allow CD music features, but this uses the built-in boot
+  ROM, not an external BIOS.
+
+  The core implements its own Mega CD BIOS call handler (MegaCDBIOSCall in
+  bus-sub-m68k.c) via HLE (high-level emulation) of Sub-CPU BIOS functions
+  including CDBIOS, CDCTRN, FDRSET, FDRCHG, DRVINIT, CDCSTOP, CDCSTAT,
+  CDCREAD, and others.
+
+files: []
+
+analysis:
+  tmss:
+    supported: false
+    notes: |
+      TMSS is not implemented. No ROM loaded, no "Produced by Sega" check.
+      No references to TMSS exist anywhere in the codebase.
+
+  megacd_bios:
+    external_required: false
+    builtin_boot_rom: true
+    boot_rom_source: "https://github.com/Clownacy/clownmdemu-mcd-boot"
+    boot_rom_location: "source/mega-cd-boot-rom.c (16384 uint16 entries = 32 KB)"
+    bus_mapping: "0x400000-0x41FFFF (address & 0x20000 == 0)"
+    source_ref: "bus-main-m68k.c:19-21, bus-main-m68k.c:484-494"
+    bios_hle: true
+    hle_source_ref: "bus-sub-m68k.c:64 (MegaCDBIOSCall)"
+    notes: |
+      The Mega CD boot ROM is an open-source replacement compiled into the
+      binary. Sub-CPU BIOS calls are handled via HLE. No external Sega CD
+      BIOS files (bios_CD_E/U/J.bin) are needed.
--- a/emulators/freeintv_ts_overlay.yml
+++ b/emulators/freeintv_ts_overlay.yml
@@ -0,0 +1,49 @@
+emulator: "FreeIntv (Touchscreen Overlay)"
+type: libretro
+source: "https://github.com/libretro/FreeIntv"
+cores:
+  - freeintv
+systems:
+  - intellivision
+
+notes: |
+  Same repo and core as FreeIntv. The touchscreen overlay feature is a
+  compile-time option within the same codebase, not a separate core. The
+  library_name is "freeintv" (src/libretro.c:1413), identical to the
+  non-overlay build.
+
+  The overlay system adds an onscreen interactive keypad for touchscreen
+  and mouse input. It is toggled via core option freeintv_multiscreen_overlay
+  (src/libretro_core_options.h:82-85). When enabled, the display splits into
+  game + keypad side-by-side (multi-screen mode).
+
+  Visual assets (controller base frame, banner, default keypad image) are
+  compiled into the binary from C headers: banner.h, keypad_frame_graphic.h,
+  default_keypad_image.h. These are NOT files the user needs to provide.
+
+  ROM-specific overlays are optional 370x600 PNG files placed by the user in
+  system/freeintv_overlays/<rom_name>.png. These are cosmetic per-game keypad
+  images and are not BIOS files.
+
+  BIOS loading is unchanged from the base FreeIntv core. retro_load_game()
+  (src/libretro.c:1169-1174) loads exec.bin and grom.bin from the system
+  directory with no variation based on overlay mode.
+
+bios_identical_to: freeintv
+
+files:
+  - name: "exec.bin"
+    system: intellivision
+    required: true
+    size: 8192
+    md5: 62e761035cb657903761800f4437b8af
+    note: "Executive ROM. Same file as base FreeIntv."
+    source_ref: "src/intv.c:47-71, src/libretro.c:1169"
+
+  - name: "grom.bin"
+    system: intellivision
+    required: true
+    size: 2048
+    md5: 0cd5946c6473e42e8e4c2137785e427f
+    note: "Graphics ROM. Same file as base FreeIntv."
+    source_ref: "src/intv.c:73-98, src/libretro.c:1173"
--- a/emulators/gw.yml
+++ b/emulators/gw.yml
@@ -0,0 +1,43 @@
+emulator: "Game & Watch"
+type: libretro
+source: "https://github.com/libretro/gw-libretro"
+cores:
+  - gw
+systems:
+  - handheld-electronic
+
+notes: |
+  gw-libretro runs Game & Watch simulators converted from MADrigal's Pascal
+  source code via pas2lua. Each game is a self-contained .mgw archive (bzip2
+  compressed tar v7) containing Lua scripts, sprites, and sound data.
+
+  retro_get_system_info (libretro.c:187-194) sets valid_extensions to "mgw",
+  need_fullpath to false, and block_extract to false. The core reads content
+  entirely from the retro_game_info buffer passed by the frontend.
+
+  retro_load_game (libretro.c:256-310) passes the content buffer to
+  gwrom_init() which decompresses and parses the tar archive in memory.
+  gwlua_create() then initializes the Lua VM from the archive entries.
+
+  The core never calls RETRO_ENVIRONMENT_GET_SYSTEM_DIRECTORY, never opens
+  files from the filesystem, and has no firmware or BIOS dependencies.
+  All game data is bundled in the .mgw content files available from
+  libretro's buildbot (bot.libretro.com/assets/cores/HandheldElectronicGame/).
+
+  No external BIOS or firmware files are needed.
+
+files: []
+
+analysis:
+  content_format:
+    extension: ".mgw"
+    archive_type: "tar v7 + bzip2"
+    decompression: "gwrom.c using bundled bzip2 library"
+    source_ref: "gwrom/gwrom.h:21-27"
+  game_engine:
+    language: "Lua (bundled lua 5.3)"
+    runtime: "gwlua (gwlua/)"
+    rendering: "retroluxury (retroluxury/)"
+    resolution: "128x128 base, variable via gwlua_set_fb/gwlua_zoom"
+  filesystem_access: false
+  system_directory_used: false
--- a/emulators/m2000.yml
+++ b/emulators/m2000.yml
@@ -0,0 +1,75 @@
+emulator: M2000
+type: libretro
+source: "https://github.com/p2000t/M2000"
+cores:
+  - m2000
+systems:
+  - philips-p2000t
+
+notes: |
+  M2000 is a Philips P2000T home computer emulator ported to libretro.
+
+  The libretro port does NOT require any external BIOS or ROM files.
+  All required ROMs are compiled directly into the core binary via
+  src/libretro/m2000_roms.h:
+
+    - monitor_rom (4096 bytes) - P2000T monitor ROM, loaded at 0x0000-0x0FFF
+    - basic_nl_rom (16384 bytes) - Dutch BASIC cartridge ROM, loaded at 0x1000-0x4FFF
+
+  The SAA5050 teletext font is also embedded via src/libretro/m2000_saa5050.h.
+
+  retro_init() at src/libretro/m2000_libretro.c:444 calls:
+    InitP2000(monitor_rom, basic_nl_rom)
+  which copies the embedded arrays directly into the ROM memory space
+  (src/P2000.c:282-283 and 308-311), bypassing all file I/O.
+
+  The standalone (non-libretro) version loads these as external files:
+    - P2000ROM.bin (monitor ROM, 4096 bytes)
+    - BASIC.bin (BASIC cartridge ROM, 16384 bytes)
+    - Default.fnt (SAA5050 font, 2240 bytes)
+  These files exist in the repo root for the standalone build only.
+
+  The core accepts .cas (cassette) content and can also run with no
+  content to boot directly into P2000T BASIC.
+
+files: []
+
+platform_details:
+  bios_mapping:
+    target: "20K ROM space: 0x0000-0x0FFF monitor, 0x1000-0x4FFF BASIC cartridge"
+    source_ref: "src/P2000.c:249-311, src/libretro/m2000_libretro.c:444"
+    notes: |
+      InitP2000() allocates 20K (0x5000) for ROM and 4K for VRAM.
+      The monitor ROM occupies the first 4K, the BASIC cartridge ROM
+      occupies the next 16K. In the libretro build, both are passed
+      as in-memory byte arrays from the embedded header.
+
+  embedded_roms:
+    monitor_rom:
+      source_ref: "src/libretro/m2000_roms.h:1372"
+      size: 4096
+    basic_nl_rom:
+      source_ref: "src/libretro/m2000_roms.h:1"
+      size: 16384
+    saa5050_fnt:
+      source_ref: "src/libretro/m2000_saa5050.h:1"
+      note: "Teletext character generator font, also embedded"
+
+  standalone_files:
+    note: |
+      The standalone build (allegro/SDL) loads P2000ROM.bin, BASIC.bin,
+      and Default.fnt from disk via fopen(). The libretro build skips
+      this entirely by passing embedded arrays to InitP2000().
+    files:
+      - name: "P2000ROM.bin"
+        size: 4096
+        md5: 2a9c5b22537738b66f4e619734318c15
+        sha1: 4dbb28adad30587f2ea536ba116898d459faccac
+      - name: "BASIC.bin"
+        size: 16384
+        md5: 2191811aa64f8e7f273ce0f462374728
+        sha1: fb5100436c99634a2592a10dff867f85bcff7aec
+      - name: "Default.fnt"
+        size: 2240
+        md5: e06dd73b8a149990f7722eabbe4f286f
+        sha1: dc3508afcafb38fc33e883b0caf4cf3909998a07
--- a/emulators/mesen.yml
+++ b/emulators/mesen.yml
@@ -0,0 +1,91 @@
+emulator: Mesen
+type: libretro
+source: "https://github.com/libretro/Mesen"
+systems: [nintendo-nes, nintendo-fds]
+
+notes: |
+  Mesen is a cycle-accurate NES/Famicom emulator (the original, NES-only
+  version -- not Mesen2 which adds SNES/GB/PCE). NES cartridge games
+  need no BIOS. Famicom Disk System games require the FDS BIOS ROM.
+
+  The core tries two filenames for the FDS BIOS: FdsBios.bin first, then
+  disksys.rom as fallback. Both are loaded from the system directory root
+  (GetHomeFolder = RETRO_ENVIRONMENT_GET_SYSTEM_DIRECTORY). If neither is
+  found or the file is not exactly 8192 bytes, FDS games fail to load.
+
+  The Study Box is an obscure Famicom tape-based learning peripheral
+  (mapper 186). Its BIOS (StudyBox.bin, 256 KB) is loaded the same way.
+  Only needed for Study Box tape dumps (.stbx format).
+
+  MesenDB.txt (game database for CRC-based ROM identification) is baked
+  into the core binary as MesenDB.inc. An external file in the system
+  directory overrides the built-in copy but is never required.
+
+  MesenPalette.pal is an optional custom palette file, loaded only when
+  the mesen_palette core option is set to Custom. Accepts 192 bytes
+  (64 colors) or 1536 bytes (512 colors with emphasis combos). Multiple
+  palettes exist so no canonical hash.
+
+  HdPacks go in system/HdPacks/<rom_name>/ -- not BIOS files, ignored
+  here.
+
+  File path construction: Libretro/libretro.cpp retro_init() sets
+  FolderUtilities::SetHomeFolder(systemFolder). All BIOS lookups use
+  FolderUtilities::CombinePath(GetHomeFolder(), filename) -- flat,
+  no subdirectories.
+
+files:
+  # --- Famicom Disk System BIOS (required for FDS games) ---
+  - name: "disksys.rom"
+    system: nintendo-fds
+    description: "FDS BIOS ROM"
+    required: true
+    size: 8192
+    md5: "ca30b50f880eb660a320674ed365ef7a"
+    sha1: "57fe1bdee955bb48d357e463ccbf129496930b62"
+    source_ref: "Core/FdsLoader.cpp:45-60 (LoadBios), Core/FdsLoader.cpp:140-146 (LoadRom validates size == 0x2000)"
+    notes: "Mapped at 0xE000-0xFFFF as PRG ROM bank 0. Core tries FdsBios.bin first, falls back to disksys.rom. CRC32 0x5E607DCF (standard Famicom). Size must be exactly 8192 bytes or BiosMissing is set."
+
+  # --- FDS BIOS alternate filename ---
+  - name: "FdsBios.bin"
+    system: nintendo-fds
+    description: "FDS BIOS ROM (Mesen-preferred filename)"
+    required: false
+    size: 8192
+    md5: "ca30b50f880eb660a320674ed365ef7a"
+    sha1: "57fe1bdee955bb48d357e463ccbf129496930b62"
+    source_ref: "Core/FdsLoader.cpp:50 (primary lookup path)"
+    notes: "Same file as disksys.rom. Mesen checks this name first. Only one of the two is needed."
+
+  # --- Study Box BIOS (required for Study Box tape content) ---
+  - name: "StudyBox.bin"
+    system: nintendo-nes
+    description: "Famicom Study Box BIOS ROM"
+    required: false
+    size: 262144
+    md5: ~
+    sha1: ~
+    source_ref: "Core/StudyBoxLoader.cpp:125-133 (LoadBios), Core/StudyBoxLoader.cpp:146-157 (LoadRom validates size == 0x40000)"
+    notes: "256 KB BIOS for the Study Box tape peripheral (mapper 186, iNES mapper 65533). Only needed for .stbx tape dumps. Extremely obscure hardware, no widely-known hash."
+
+  # --- Game database (optional, baked-in fallback) ---
+  - name: "MesenDB.txt"
+    system: nintendo-nes
+    description: "Mesen game database for CRC-based ROM identification"
+    required: false
+    size: ~
+    md5: ~
+    sha1: ~
+    source_ref: "Core/GameDatabase.cpp:74-81 (InitDatabase), Libretro/MesenDB.inc (baked-in copy)"
+    notes: "CSV game database keyed by CRC32. Used for mapper, mirroring, input type, and VS System detection. A complete copy is compiled into the binary, so this file is optional. Placing a newer version in the system directory overrides the built-in data."
+
+  # --- Custom palette (optional, core option mesen_palette = Custom) ---
+  - name: "MesenPalette.pal"
+    system: nintendo-nes
+    description: "External NES color palette"
+    required: false
+    size: 192
+    md5: ~
+    sha1: ~
+    source_ref: "Libretro/libretro.cpp:301-323 (load_custom_palette)"
+    notes: "Loaded when mesen_palette core option is Custom. Accepts 192 bytes (64 RGB triplets) or 1536 bytes (512 entries for emphasis combos). Falls back to built-in default palette. Multiple valid palettes exist so no canonical hash."
--- a/emulators/pd777.yml
+++ b/emulators/pd777.yml
@@ -0,0 +1,56 @@
+emulator: PD777
+type: libretro
+source: "https://github.com/W88DodPECuThLOl/PD777"
+cores:
+  - pd777
+systems:
+  - epochcv
+
+notes: |
+  PD777 is an Epoch Cassette Vision emulator (NEC uPD777C CPU) with a libretro
+  interface, by W88DodPECuThLOl.
+
+  No BIOS or firmware files required. The .info file declares firmware_count = 0.
+
+  Game loading in source/libretro/libretro.cpp:retro_load_game() (line 386-474).
+  The core loads a code ROM file (.bin777) directly from the content path, then
+  attempts to load a pattern ROM file (.ptn777) by replacing the extension.
+
+  If neither file is found, the core falls back to hardcoded ROM data compiled
+  from source/core/rom.cpp (Battle Vader program + pattern ROM dumps from
+  oguchi-rd.com).
+
+  The code ROM supports three formats:
+    - Raw order: exactly 0xF00 bytes, program words in sequential address order
+    - Raw address: address/data pairs (compiled-in rawRom[] array)
+    - Formatted: header starting with "_CassetteVision_000" magic, version 0 or 1,
+      includes key mapping, title, and code section at offset 0x100
+
+  The pattern ROM supports three formats:
+    - Formatted: 0x340 bytes, header "*CassetteVision*0000", 7x7 + 8x7 CG patterns
+    - Raw bitstream: 0x4D0 bytes, bit-packed 7x7 and 8x7 character patterns
+    - Built-in: fallback to patternRom[] / patternRom8[] arrays in rom.cpp
+
+  The system directory path is retrieved via RETRO_ENVIRONMENT_GET_SYSTEM_DIRECTORY
+  but is not used for any file loading.
+
+  Game identification uses a checksum over the loaded ROM to detect known cassettes
+  (Battle Vader, Galaxian, etc.) and apply per-game key mappings and bent character
+  tables. 11 cassette IDs are recognized (1-9, 11, 12).
+
+  Supported extensions: zip, bin777, ptn777.
+
+files: []
+
+platform_details:
+  cpu: "NEC uPD777C (uPD774 variant)"
+  system: "Epoch Cassette Vision (1981)"
+  region: "Japan"
+  notes: |
+    The Cassette Vision uses a NEC uPD777C (or uPD774 variant) as its main
+    processor. Program ROM and pattern/character ROM are per-cartridge, not
+    system-level. There is no system BIOS - the CPU executes directly from
+    the cartridge ROM.
+
+    The emulator supports analog paddles (4 paddles mapped to 2 analog sticks),
+    lever switches, push buttons, course switch, and a lightgun peripheral.
--- a/emulators/play.yml
+++ b/emulators/play.yml
@@ -0,0 +1,60 @@
+# Play! emulator BIOS profile
+# Generated from source analysis of https://github.com/jpd002/Play-
+# Commit analyzed: HEAD as of 2026-03-17
+
+emulator: "Play!"
+type: libretro
+core_name: play_libretro
+source: "https://github.com/jpd002/Play-"
+systems: [sony-playstation-2]
+
+bios_directory: null
+bios_detection: "hle"
+bios_selection: "not_applicable"
+
+validation:
+  method: "none"
+  note: >
+    Play! is a full HLE (High-Level Emulation) PS2 emulator. It does not load or
+    require any real PS2 BIOS dump. The LoadBIOS() function in Ee_SubSystem.cpp
+    (which would read ./vfs/rom0/scph10000.bin) is commented out in PS2VM.cpp:ResetVM().
+
+files: []
+  # No BIOS files required.
+  # IOP modules (rom0:SIO2MAN, rom0:PADMAN, rom0:MCMAN, rom0:MCSERV, etc.)
+  # are all replaced by HLE implementations in Source/iop/IopBios.cpp.
+  # The EE kernel/OS is reimplemented in Source/ee/PS2OS.cpp.
+
+virtual_filesystem:
+  # Play! uses a virtual filesystem for memory cards and disc access,
+  # but these are runtime directories, not BIOS files.
+  mc0: {default: "vfs/mc0", purpose: "Memory card slot 0 (save data)"}
+  mc1: {default: "vfs/mc1", purpose: "Memory card slot 1 (save data)"}
+  host: {default: "vfs/host", purpose: "Host filesystem access"}
+  cdrom0: {default: null, purpose: "Disc image (set per-game)"}
+
+memory_layout:
+  EE_RAM: {size: "32 MB (0x02000000)"}
+  EE_BIOS: {size: "4 MB (0x00400000)", note: "Allocated but unused, HLE replaces real BIOS"}
+  IOP_RAM: {size: "2 MB (0x00200000)"}
+  SPU_RAM: {size: "2 MB (0x00200000)"}
+
+notes: |
+  Play! does not require any PS2 BIOS files. Unlike PCSX2, it uses High-Level
+  Emulation to reimplement the PS2 kernel, IOP BIOS modules, and system services
+  entirely in C++.
+
+  Key HLE components:
+  - EE kernel: Source/ee/PS2OS.cpp (handles BootFromCDROM, BootFromFile, syscalls)
+  - IOP BIOS: Source/iop/IopBios.cpp (HLE modules for rom0:PADMAN, MCMAN, MCSERV, etc.)
+  - No rom0/rom1/erom files are loaded at runtime
+
+  The legacy LoadBIOS() function in Source/ee/Ee_SubSystem.cpp references
+  "./vfs/rom0/scph10000.bin" but this call is commented out in PS2VM::ResetVM()
+  and has no effect on emulation.
+
+  mc2_ings.ico is not referenced anywhere in Play! source code. That file is
+  specific to PCSX2's memory card icon handling, not Play!.
+
+  The libretro core supports: .elf, .iso, .cso, .isz, .bin disc images.
+  Extensions handled in main_libretro.cpp:retro_get_system_info().
--- a/emulators/race.yml
+++ b/emulators/race.yml
@@ -0,0 +1,52 @@
+emulator: RACE (Neo Geo Pocket)
+type: libretro
+source: "https://github.com/libretro/RACE"
+systems: [snk-ngp, snk-ngpc]
+
+notes: |
+  RACE is a Neo Geo Pocket and Neo Geo Pocket Color emulator, originally
+  developed for PSP (forked from Akop Karapetyan's port), adapted for
+  libretro.
+
+  No external BIOS files are required. The core contains dead code in
+  race-memory.c that would load "NPBIOS.BIN" (64KB, loaded into cpurom
+  via filestream_open), but it is compiled out with #if 0 and loadBIOS()
+  unconditionally returns 0. The comment explains: "Using a real bios
+  file causes nothing but issues" and references Card Fighters' Clash
+  Test Mode as a known failure.
+
+  Instead, the core uses a software HLE approach:
+  - A built-in koyote_bin memory dump (RAM state from a real console
+    post-boot) is copied into mainram at startup
+  - A fake SWI jump table is constructed at cpurom[0xE000] using the
+    TLCS-900H 0x1A (reg) dummy opcode to trap BIOS calls
+  - doBios() in tlcs900h.c handles 33 BIOS functions in software:
+    shutdown, clock speed, RTC, screen mode, font rendering, flash
+    read/write, communication, and sound control
+  - Interrupt vectors are set up at cpurom[0xFF00] and interrupt
+    handler code at cpurom[0xF800]
+  - CPU RAM defaults (interrupt priorities, timers) are loaded from
+    the ngpcpuram[256] table
+
+  The Z80 sound CPU is emulated in software (cz80 or DrZ80 backend).
+  Flash memory for game saves is handled internally by flash.c.
+
+  The only core option affecting system behavior is ngp_language
+  (english/japanese), which sets a RAM flag at 0x6F87.
+
+  ROM extensions: .ngp, .ngc, .ngpc, .npc
+
+files: []
+
+analysis:
+  npbios:
+    filename: NPBIOS.BIN
+    size: 65536  # 64 KB (0x10000)
+    loaded_by: "race-memory.c:loadBIOS()"
+    status: disabled
+    source_ref: "race-memory.c:337-361"
+    notes: |
+      loadBIOS() is wrapped in #if 0 and always returns 0.
+      Even if re-enabled, the realBIOSloaded=1 path has known
+      compatibility issues (e.g. Puzzle Bobble fails to boot).
+      The HLE path is the only functional code path.
--- a/emulators/vemulator.yml
+++ b/emulators/vemulator.yml
@@ -0,0 +1,72 @@
+emulator: VeMUlator
+type: libretro
+source: "https://github.com/libretro/vemulator-libretro"
+cores:
+  - vemulator
+systems:
+  - sega-vmu
+
+notes: |
+  VeMUlator is a Sega Dreamcast Visual Memory Unit (VMU/VMS) emulator ported
+  from Android (Java) to C++ for libretro. It emulates the Sanyo LC8670
+  "Potato" CPU, 128 KB flash memory, 48x32 monochrome LCD, piezo buzzer,
+  and basic timer subsystems.
+
+  No BIOS files are required. The core uses High Level Emulation (HLE) to
+  bypass the VMU firmware entirely:
+
+  - At startup, startCPU() checks the BIOSExists flag (vmu.cpp:195). When
+    false (always, in the libretro port), it calls initializeHLE() which
+    sets up SFR registers (SP=0x7F, PSW=0x02, IE=0x80, MCR=0x08, P7=0x02,
+    OCR=0xA3, BTCR=0x41) and system RAM variables directly (vmu.cpp:206-222).
+
+  - A loadBIOS() function exists in the VMU class (vmu.cpp:82-137) and can
+    handle both encrypted (XOR 0x37, 4-byte header stripped) and unencrypted
+    BIOS images (first byte must be 0x2A = JMPF opcode). Maximum accepted
+    size is 0xF004 (61444) bytes, loaded into 0xF000 (61440) bytes of ROM.
+    However, this function is never called by the libretro frontend code.
+    retro_load_game() in main.cpp only loads game flash data, with no BIOS
+    path resolution or RETRO_ENVIRONMENT_GET_SYSTEM_DIRECTORY call.
+
+  - The README lists "BIOS support" as a planned future feature.
+
+  The .info file declares no firmware entries (firmware_count absent).
+  Supported ROM formats: VMS (.vms), DCI (.dci), raw flash dump (.bin).
+  The core option "enable_flash_write" allows persistent saves for .bin files.
+
+files: []
+
+platform_details:
+  hle_implementation:
+    source_ref: "vmu.cpp:195-222"
+    sfr_init:
+      SP: "0x7F"
+      PSW: "0x02"
+      IE: "0x80"
+      MCR: "0x08"
+      P7: "0x02"
+      OCR: "0xA3"
+      BTCR: "0x41"
+    ram_init:
+      - "0x31 = 0xFF (battery level)"
+      - "0x6E = 0xFF"
+      - "P3 = 0xFF (no buttons pressed)"
+      - "BCD date/time at 0x10-0x16, raw at 0x17-0x1D"
+    notes: |
+      HLE skips the BIOS boot sequence and jumps directly into the loaded
+      game. System clock, date, and button state are initialized in RAM.
+      The EXT register is set to 1 to signal HLE mode to the CPU
+      (vmu.cpp:198-199). Games that depend on BIOS-initialized state
+      beyond what HLE provides may not work correctly.
+
+  unused_bios_loader:
+    source_ref: "vmu.cpp:82-137"
+    max_file_size: 61444
+    rom_load_size: 61440
+    encryption: "XOR 0x37 after stripping 4-byte header"
+    detection: "first byte 0x2A (JMPF) = unencrypted, otherwise encrypted"
+    notes: |
+      The loadBIOS() method is fully implemented but unreachable from the
+      libretro interface. No system directory query, no BIOS path construction,
+      and no call site exists in main.cpp. A future update could wire this up
+      to support real VMU firmware boot (file manager, clock, mini-games menu).