emulator: fMSX
type: libretro
core_classification: community_fork
source: "https://github.com/libretro/fmsx-libretro"
upstream: "https://fms.komkon.org/fMSX/"
profiled_date: "2026-03-23"
core_version: "6.0"
display_name: "Microsoft - MSX (fMSX)"
cores:
  - fmsx
systems:
  - msx
  - msx2
  - msx2plus

# fMSX is a standalone MSX emulator by Marat Fayzullin, ported to libretro.
# Supports MSX1, MSX2, and MSX2+ hardware models. Default model is MSX2+.
#
# ROM loading (fMSX/MSX.c:688-750, ResetMSX):
#   The core sets ProgDir = RetroArch system_directory, then chdir(ProgDir)
#   before calling LoadROM(). All BIOS files must be placed directly in the
#   system directory root (no subdirectories).
#
# Model selection (libretro.c:731-757):
#   Core option "fmsx_machine_type" picks MSX1/MSX2/MSX2+. Default is MSX2+.
#   MSX1 loads MSX.ROM (32 KB main BIOS).
#   MSX2 loads MSX2.ROM (32 KB) + MSX2EXT.ROM (16 KB extension).
#   MSX2+ loads MSX2P.ROM (32 KB) + MSX2PEXT.ROM (16 KB extension).
#
# Disk support (fMSX/MSX.c:780):
#   DISK.ROM is loaded when "fmsx_simbdos" option is enabled (MSX_PATCHBDOS).
#   Without it, .dsk files won't boot. The core shows a warning if DISK.ROM
#   is missing when loading disk content.
#
# Optional ROMs (fMSX/MSX.c:526-582):
#   KANJI.ROM - Kanji font (128 KB), loaded unconditionally if present
#   FMPAC.ROM - FM-PAC cartridge (64 KB), loaded into first free slot
#   MSXDOS2.ROM - MSX-DOS 2 (64 KB), loaded when "fmsx_dos2" enabled and MSX2+
#   PAINTER.ROM - Paint utility (64 KB), loaded for MSX2/MSX2+
#   RS232.ROM - RS-232C serial (16 KB + 256 B), loaded into slot 3:3
#   GMASTER2.ROM - Konami GameMaster2 cart, loaded when "fmsx_game_master" enabled
#   GMASTER.ROM - Konami GameMaster (fallback if GMASTER2.ROM missing)
#   CMOS.ROM - RTC settings persistence, saved/loaded automatically
#
# All ROMs listed below are bundled in fMSX/ROMs/ inside the repo source.
# They are the standard C-BIOS-compatible generic MSX BIOS set from fMSX.

notes: |
  Place all ROM files directly in the RetroArch system directory. No subdirectory
  needed. The core does chdir() to system_dir before loading.

  The default model is MSX2+, which needs MSX2P.ROM and MSX2PEXT.ROM. If you only
  play cartridge ROMs, these two files are sufficient. For disk games (.dsk), also
  add DISK.ROM and enable "Simulate DiskROM" in core options.

  KANJI.ROM and FMPAC.ROM are loaded automatically when present, no option needed.

files:
  # -- MSX1 BIOS --

  - name: MSX.ROM
    size: 32768
    md5: aa95aea2563cd5ec0a0919b44cc17d47
    sha1: 409e82adac40f6bdd18eb6c84e8b2fbdc7fb5498
    required: true
    system: msx
    bundled: true
    note: "MSX1 main BIOS (32 KB). Loaded for MSX1 model (fMSX/MSX.c:693)."
    source_ref: "fMSX/ROMs/MSX.ROM"

  # -- MSX2 BIOS --

  - name: MSX2.ROM
    size: 32768
    md5: ec3a01c91f24fbddcbcab0ad301bc9ef
    sha1: 6103b39f1e38d1aa2d84b1c3219c44f1abb5436e
    required: true
    system: msx2
    bundled: true
    note: "MSX2 main BIOS (32 KB). Loaded for MSX2 model (fMSX/MSX.c:709)."
    source_ref: "fMSX/ROMs/MSX2.ROM"

  - name: MSX2EXT.ROM
    size: 16384
    md5: 2183c2aff17cf4297bdb496de78c2e8a
    sha1: 5c1f9c7fb655e43d38e5dd1fcc6b942b2ff68b02
    required: true
    system: msx2
    bundled: true
    note: "MSX2 extension BIOS (16 KB). Loaded alongside MSX2.ROM (fMSX/MSX.c:710)."
    source_ref: "fMSX/ROMs/MSX2EXT.ROM"

  # -- MSX2+ BIOS (default model) --

  - name: MSX2P.ROM
    size: 32768
    md5: 6d8c0ca64e726c82a4b726e9b01cdf1e
    sha1: e2fbd56e42da637609d23ae9df9efd1b4241b18a
    required: true
    system: msx2plus
    bundled: true
    note: "MSX2+ main BIOS (32 KB). Loaded for MSX2+ model, the default (fMSX/MSX.c:731)."
    source_ref: "fMSX/ROMs/MSX2P.ROM"

  - name: MSX2PEXT.ROM
    size: 16384
    md5: 7c8243c71d8f143b2531f01afa6a05dc
    sha1: fe0254cbfc11405b79e7c86c7769bd6322b04995
    required: true
    system: msx2plus
    bundled: true
    note: "MSX2+ extension BIOS (16 KB). Loaded alongside MSX2P.ROM (fMSX/MSX.c:732)."
    source_ref: "fMSX/ROMs/MSX2PEXT.ROM"

  # -- Disk support --

  - name: DISK.ROM
    size: 16384
    md5: 80dcd1ad1a4cf65d64b7ba10504e8190
    sha1: 032cb1c1c75b9a191fa1230978971698d9d2a17f
    required: false
    bundled: true
    note: "Disk controller BIOS (16 KB). Needed for .dsk content. Enable 'Simulate DiskROM' option (fMSX/MSX.c:780)."
    source_ref: "fMSX/ROMs/DISK.ROM"

  # -- Optional expansion ROMs --

  - name: FMPAC.ROM
    size: 65536
    md5: 6f69cc8b5ed761b03afd78000dfb0e19
    sha1: 9d789166e3caf28e4742fe933d962e99618c633d
    required: false
    bundled: true
    note: "FM-PAC cartridge ROM (64 KB, YM2413 FM synthesis). Auto-loaded into first free slot (fMSX/MSX.c:557)."
    source_ref: "fMSX/ROMs/FMPAC.ROM"

  - name: KANJI.ROM
    size: 131072
    md5: febe8782b466d7c3b16de6d104826b34
    sha1: 84a645becec0a25d3ab7a909cde1b242699a8662
    required: false
    bundled: true
    note: "Kanji font ROM (128 KB). Auto-loaded if present, no option needed (fMSX/MSX.c:530)."
    source_ref: "fMSX/ROMs/KANJI.ROM"

  - name: MSXDOS2.ROM
    size: 65536
    md5: 6418d091cd6907bbcf940324339e43bb
    sha1: c36c9e0f96738a340381e23b4f97245388801a46
    required: false
    bundled: true
    note: "MSX-DOS 2 ROM (64 KB). Loaded when 'fmsx_dos2' option enabled and model is MSX2 or MSX2+ (fMSX/MSX.c:545)."
    source_ref: "fMSX/ROMs/MSXDOS2.ROM"

  - name: PAINTER.ROM
    size: 65536
    md5: 403cdea1cbd2bb24fae506941f8f655e
    sha1: 7fd2a28c4fdaeb140f3c8c8fb90271b1472c97b9
    required: false
    bundled: true
    note: "Paint utility ROM (64 KB). Auto-loaded for MSX2 and MSX2+ models (fMSX/MSX.c:552)."
    source_ref: "fMSX/ROMs/PAINTER.ROM"

  - name: RS232.ROM
    size: 16640
    md5: 279efd1eae0d358eecd4edc7d9adedf3
    sha1: 7aec0134ad6a5177f4056fcb6047083e8e00529b
    required: false
    bundled: true
    note: "RS-232C serial interface ROM (16 KB + 256 B). Loaded into slot 3:3 (fMSX/MSX.c:533)."
    source_ref: "fMSX/ROMs/RS232.ROM"

  # -- GameMaster (not bundled, requires core option) --

  - name: GMASTER2.ROM
    required: false
    bundled: false
    note: "Konami GameMaster2 cartridge ROM. Loaded when 'fmsx_game_master' option enabled (fMSX/MSX.c:576)."

  - name: GMASTER.ROM
    required: false
    bundled: false
    note: "Konami GameMaster cartridge ROM. Fallback if GMASTER2.ROM is missing (fMSX/MSX.c:580)."

  # -- CMOS persistence (auto-generated, not a BIOS) --

  - name: CMOS.ROM
    required: false
    bundled: false
    note: "RTC/CMOS settings. Auto-saved by the core on exit, auto-loaded on start (fMSX/MSX.c:526)."

  # -- Text fonts (selectable via fmsx_font core option) --

  - name: DEFAULT.FNT
    required: false
    bundled: true
    md5: 85b38e4128bbc300e675f55b278683a8
    note: "Default text font. Loaded by LoadFNT() (fMSX/MSX.c:523). Same content as CYRILLIC.FNT."
    source_ref: "fMSX/ROMs/DEFAULT.FNT, libretro.c:1546"

  - name: ITALIC.FNT
    required: false
    bundled: true
    md5: c83e50e9f33b8dd893c414691822740d
    note: "Italic text font."
    source_ref: "fMSX/ROMs/ITALIC.FNT, libretro.c:1546"

  - name: INTERNAT.FNT
    required: false
    bundled: true
    md5: ac4f4a90c1b1887db48ded39c9d9c847
    note: "International text font."
    source_ref: "fMSX/ROMs/INTERNAT.FNT, libretro.c:1546"

  - name: CYRILLIC.FNT
    required: false
    bundled: true
    md5: 85b38e4128bbc300e675f55b278683a8
    note: "Cyrillic text font. Same content as DEFAULT.FNT."
    source_ref: "fMSX/ROMs/CYRILLIC.FNT, libretro.c:1546"

  - name: KOREAN.FNT
    required: false
    bundled: true
    md5: 73291e76638a2f5aa2eceb843df468f4
    note: "Korean text font."
    source_ref: "fMSX/ROMs/KOREAN.FNT, libretro.c:1546"

  - name: JAPANESE.FNT
    required: false
    bundled: true
    md5: aa28f0703b951a6be8df3e28e20d263d
    note: "Japanese text font."
    source_ref: "fMSX/ROMs/JAPANESE.FNT, libretro.c:1546"

  # -- Cartridge identification database --

  - name: CARTS.CRC
    required: false
    bundled: false
    note: "CRC database for cartridge identification and mapper detection. Tried first, before CARTS.SHA (fMSX/MSX.c:2697)."

  - name: CARTS.SHA
    required: false
    bundled: true
    md5: 74b0f217fa0e2b8bb5a2f8e2ecc69da3
    note: "SHA1 database for cartridge identification and mapper detection. Fallback when CARTS.CRC absent (fMSX/MSX.c:2712)."
    source_ref: "fMSX/ROMs/CARTS.SHA"