emulator: beetle_saturn
type: libretro
core_classification: community_fork
core: mednafen_saturn_libretro
source: "https://github.com/libretro/beetle-saturn-libretro"
upstream: "https://mednafen.github.io/"
profiled_date: "2026-03-24"
source_commit: "65f05fa66f83e65e33be83aa433d883b4fd9509a"
core_version: "v1.32.1"
display_name: "Sega - Saturn (Beetle Saturn)"
cores:
  - mednafen_saturn
  - beetle-saturn
systems:
  - sega-saturn
  - sega-stv

notes: |
  Libretro port of Mednafen's Saturn emulation module, converted to C and
  reporting v1.32.1 (libretro.c:57). Region auto-detection reads the disc header
  and selects the matching BIOS. Manual override via beetle_saturn_region option.

  InitCommon() returns false if the BIOS file is missing or not exactly 512 KB.
  Both region BIOS files are required for full region coverage.

  KOF95 and Ultraman ROM carts are loaded when the cart type is set via core
  option or auto-detected from the internal game database.

  ST-V content is a game ZIP or a bare ROM matched against the ST-V game
  table (libretro.c:1207-1227, libretro.c:1261-1281). The cabinet region of
  the matched game selects one of three ST-V BIOS images
  (mednafen/ss/ss.c:1829-1843), read as a bare file from the system directory
  or, when that file is absent, as the member of the same name in stvbios.zip
  there (mednafen/ss/ss.c:1875-1942). Either form may be 131072 or 524288
  bytes (mednafen/ss/ss.c:1911-1912, mednafen/ss/ss.c:1962).

  The Video CD Card is driven through the CD block. With the
  beetle_saturn_mpeg_card option enabled, CDB_Init opens mpeg_card.bin in the
  system directory and MPEG_Init keeps up to 0x80000 bytes of it; without the
  ROM the card answers commands but does not authenticate
  (libretro.c:578-586, mednafen/settings.c:68-69, mednafen/ss/cdb.c:1315-1332,
  mednafen/ss/mpeg.c:423-450).

  No setting names a file for the bootable ROM cart: ss.cart.bootrom_path
  has no value in the port (mednafen/ss/cart.c:242-262,
  mednafen/settings.c:60-71).

files:
  - name: "sega_101.bin"
    system: sega-saturn
    region: [japan, asia-ntsc]
    required: true
    size: 524288
    validation: [size]
    note: "Saturn BIOS v1.01 (Japan). Used when region is JP or Asia NTSC."
    source_ref: "mednafen/ss/ss.c:1846 (region filename), mednafen/ss/ss.c:1871-1988 (open, size check, read, sha256)"

  - name: "mpr-17933.bin"
    system: sega-saturn
    region: [north-america, europe, south-korea, asia-pal, brazil, latin-america]
    required: true
    size: 524288
    validation: [size]
    note: "Saturn BIOS (NA/EU). Used for all non-JP/Asia-NTSC regions."
    source_ref: "mednafen/ss/ss.c:1848 (region filename), mednafen/ss/ss.c:1871-1988 (open, size check, read, sha256)"

  - name: "mpr-18811-mx.ic1"
    system: sega-saturn
    required: false
    size: 2097152
    note: "KOF95 expansion ROM cart. Loaded when cart type set to KOF95."
    source_ref: "mednafen/ss/cart.c:200-215 (firmware path + open), mednafen/ss/cart/rom.c:51 (CART_ROM_Init)"

  - name: "mpr-19367-mx.ic1"
    system: sega-saturn
    required: false
    size: 2097152
    note: "Ultraman expansion ROM cart. Loaded when cart type set to Ultraman."
    source_ref: "mednafen/ss/cart.c:200-215 (firmware path + open), mednafen/ss/cart/rom.c:51 (CART_ROM_Init)"

  - name: "epr-20091.ic8"
    system: sega-stv
    region: [japan, asia-ntsc]
    required: true
    size: [131072, 524288]
    validation: [size]
    note: "ST-V BIOS for Japan and Asia NTSC cabinets. Read from stvbios.zip when the bare file is absent."
    source_ref: "mednafen/ss/ss.c:1838-1839 (region filename), mednafen/ss/ss.c:1871-1988 (open, zip fallback, size check, read, sha256)"

  - name: "epr-17952a.ic8"
    system: sega-stv
    region: [north-america, brazil, latin-america]
    required: true
    size: [131072, 524288]
    validation: [size]
    note: "ST-V BIOS for North America and Central and South America cabinets. Read from stvbios.zip when the bare file is absent."
    source_ref: "mednafen/ss/ss.c:1840-1841 (region filename), mednafen/ss/ss.c:1871-1988 (open, zip fallback, size check, read, sha256)"

  - name: "epr-17954a.ic8"
    system: sega-stv
    region: [europe, south-korea, asia-pal]
    required: true
    size: [131072, 524288]
    validation: [size]
    note: "ST-V BIOS for every other cabinet region. Read from stvbios.zip when the bare file is absent."
    source_ref: "mednafen/ss/ss.c:1842-1843 (region filename), mednafen/ss/ss.c:1871-1988 (open, zip fallback, size check, read, sha256)"

  - name: "mpeg_card.bin"
    system: sega-saturn
    required: false
    note: "Video CD Card firmware, opened when beetle_saturn_mpeg_card is enabled. At most 0x80000 bytes are kept and nothing is checked; without it the card does not authenticate."
    source_ref: "mednafen/settings.c:68-69 (filename), mednafen/ss/cdb.c:1315-1332 (open), mednafen/ss/mpeg.c:423-450 (read)"

  - name: "satar4mp.bin"
    system: sega-saturn
    required: false
    min_size: 262144
    validation: [size]
    note: "Action Replay 4M Plus firmware. The first 0x40000 bytes are read as big-endian words and a shorter file leaves the cart slot empty; no hash is checked. Unfinished in source (mednafen/ss/cart/ar4mp.c:22-24), needs CPU UBC emulation. Neither the beetle_saturn_cart option (libretro.c:512-530) nor the game table of mednafen/ss/db.c yields CART_AR4MP, so the case is not reached."
    source_ref: "mednafen/settings.c:66-67 (filename), mednafen/ss/cart.c:218-236 (CART_AR4MP case), mednafen/ss/cart/ar4mp.c:181 (0x40000-byte read)"