emulator: Flycast
type: standalone + libretro
core_classification: official_port
source: "https://github.com/flyinghead/flycast"
logo: "https://raw.githubusercontent.com/flyinghead/flycast/master/shell/linux/flycast.png"
profiled_date: "2026-10-21"
source_commit: "6d81b998169b916ad7d7d6f403f7dc2c18e2aea5"
core_version: "Git"
display_name: "Sega - Dreamcast/Naomi (Flycast)"
cores:
  - flycast
  - flycast_dev
  - flycastvl
  - "flycast-next"
  - "flycastsa"
  - "flycast_32b"
systems:
  - sega-dreamcast
  - sega-naomi
  - sega-naomi2
  - sega-atomiswave
  - sega-systemsp
standalone_directories:
  - "Dreamcast.BiosPath"
  - "find_user_data_dir"
  - "$XDG_DATA_HOME/flycast"
  - "$HOME/.local/share/flycast"
  - "FLYCAST_BIOS_PATH"

data_root:
  android:
    path: "Android/data/com.flycast.emulator/files/data"
    source_ref: "shell/android-studio/flycast/src/main/java/com/flycast/emulator/BaseGLActivity.java:92-97,442-447, shell/android-studio/flycast/src/main/jni/src/Android.cpp:143-159, shell/android-studio/flycast/build.gradle.kts:21"
    note: "data/ under the home directory set in the app settings, getFilesDir() when no external storage is mounted"
  ios:
    path: "Documents"
    source_ref: "shell/apple/emulator-ios/emulator/FlycastViewController.mm:198-201"
    note: "the app's sandbox Documents folder, with no data/ subfolder"
  windows:
    path: "<folder of flycast.exe>/data"
    source_ref: "core/windows/winmain.cpp:59-78"
    note: "the UWP build uses data/ under the app's LocalFolder (core/windows/winmain.cpp:80-89)"
  macos:
    path: "~/Library/Application Support/Flycast/data"
    source_ref: "shell/apple/emulator-osx/emulator-osx/osx-main.mm:78-102"
    note: "~/.flycast/data when ~/.flycast exists. A second running instance appends its number to the folder"
  linux:
    path: "$XDG_DATA_HOME/flycast, else ~/.local/share/flycast"
    source_ref: "core/linux-dist/main.cpp:74-99,247"

notes: |
  The libretro core is built from flyinghead/flycast, the same tree as the
  standalone emulator: the wrapper lives in shell/libretro and is compiled
  with -DLIBRETRO=ON.

  Flycast has a built-in HLE BIOS (reios) for Dreamcast that boots most
  games without a real boot ROM. A short list of product ids forces the
  real BIOS (core/emulator.cpp:277-278) and is told "This game requires a
  real BIOS" when it is absent (core/emulator.cpp:616-621). Without content,
  the core boots the BIOS and fails when none is found
  (core/emulator.cpp:601-605). Arcade systems (NAOMI, NAOMI 2, Atomiswave,
  System SP) load MAME-format BIOS archives.

  The libretro port appends "dc/" to the system directory
  (shell/libretro/libretro.cpp:2252-2253). All files below are relative to
  system_dir/dc/.

  The standalone emulator looks for each file in the BIOS paths the user
  configures, then in its data directory, then in the system data
  directories, then in the content directories, and writes the flash back to
  the data directory (core/oslib/oslib.cpp:118-196,
  core/stdclass.cpp:95-125). The data directory, given per system in
  data_root, is the data/ folder of the configuration directory except on
  Linux and iOS. standalone_path is relative to it. The BIOS paths are the
  Dreamcast.BiosPath setting (core/cfg/option.cpp:144), the system data
  directories take $FLYCAST_BIOS_PATH (core/linux-dist/main.cpp:198-202), and
  find_user_data_dir() returns the data directory
  (core/linux-dist/main.cpp:74, core/linux-dist/main.cpp:247).

  Only the Dreamcast reads flat files. The prefix is dc_ for Dreamcast
  (core/hw/flashrom/nvmem.cpp:35-50), and the boot ROM is searched as
  {prefix}boot.bin then {prefix}bios.bin (core/hw/flashrom/nvmem.cpp:304).
  Flash is {prefix}nvmem.bin and is created when absent
  (core/hw/flashrom/nvmem.cpp:252-256). Arcade platforms return before the
  boot ROM search (core/hw/flashrom/nvmem.cpp:300-302), and their flash is a
  per-game save file. The system font is a resource compiled into the
  binary (core/reios/reios.cpp:761-764).

  Arcade BIOS archives are opened as <name>.zip, then <name>.7z
  (core/hw/naomi/naomi_cart.cpp:75-78), first in system_dir/dc, then in
  the content directory (shell/libretro/oslib.cpp:118-130). Each ROM inside
  is looked up by CRC, then by file name, in the game archive, its parent,
  then the BIOS archive (core/hw/naomi/naomi_cart.cpp:89-106). The blob of
  the configured region is mapped first, any region otherwise, and a game
  whose BIOS cannot be loaded aborts (core/hw/naomi/naomi_cart.cpp:196-207).
  Games whose bios field is naomi2 run as NAOMI 2 and those whose bios
  field is segasp as System SP (core/hw/naomi/naomi_cart.cpp:810-821).

  BIOS[] also declares naomidev and naomigd. No entry of Games[] carries
  either name in its bios field, so neither archive is opened. naomi-jp-d
  and naomi-ko-h read naomi.zip (core/hw/naomi/naomi_roms.cpp:219-242).

files:
  # -------------------------------------------------------
  # Sega Dreamcast
  # -------------------------------------------------------
  - name: "dc_boot.bin"
    path: "dc/dc_boot.bin"
    standalone_path: "dc_boot.bin"
    aliases: ["dc_bios.bin"]
    system: sega-dreamcast
    required: false
    hle_fallback: true
    size: 2097152
    note: "Dreamcast boot ROM. reios is used when it is absent, except for the product ids that force the real BIOS. Searched as dc_boot.bin then dc_bios.bin."
    source_ref: "core/hw/flashrom/nvmem.cpp:298-316, core/emulator.cpp:613-622"

  - name: "dc_nvmem.bin"
    path: "dc/dc_nvmem.bin"
    standalone_path: "dc_nvmem.bin"
    system: sega-dreamcast
    required: false
    hle_fallback: true
    size: 131072
    note: "Dreamcast flash memory. Created with factory settings when absent, written back on exit."
    source_ref: "core/hw/flashrom/nvmem.cpp:252-256, core/hw/flashrom/nvmem.cpp:321-322"

  # -------------------------------------------------------
  # Sega NAOMI
  # -------------------------------------------------------
  - name: "naomi.zip"
    path: "dc/naomi.zip"
    standalone_path: "naomi.zip"
    system: sega-naomi
    required: true
    category: bios_zip
    note: "NAOMI system BIOS archive. Games with no bios field or with naomi, naomi-jp-d or naomi-ko-h read it and abort without it."
    source_ref: "core/hw/naomi/naomi_roms.cpp:86-144, core/hw/naomi/naomi_roms.cpp:219-242, core/hw/naomi/naomi_cart.cpp:196-207"
    contents:
      - name: "epr-21576h.ic27"
        description: Japan
        size: 2097152
        crc32: "d4895685"
      - name: "epr-21576g.ic27"
        description: Japan
        size: 2097152
        crc32: "d2a1c6bf"
      - name: "epr-21578h.ic27"
        description: Export
        size: 2097152
        crc32: "7b452946"
      - name: "epr-21578g.ic27"
        description: Export
        size: 2097152
        crc32: "55413214"
      - name: "epr-21577h.ic27"
        description: USA
        size: 2097152
        crc32: "fdf17452"
      - name: "epr-21577g.ic27"
        description: USA
        size: 2097152
        crc32: "25f64af7"
      - name: "epr-21579d.ic27"
        description: Korea
        size: 2097152
        crc32: "33513691"
      - name: "epr-21576h_multi.ic27"
        description: "Multi-region, the BIOS of naomi-ko-h"
        size: 2097152
        crc32: "cce01f1f"
      - name: "epr-21576d.ic27"
        description: "Japan, the BIOS of naomi-jp-d"
        size: 2097152
        crc32: "3b2afa7b"

  - name: "airlbios.zip"
    path: "dc/airlbios.zip"
    standalone_path: "airlbios.zip"
    system: sega-naomi
    required: false
    category: bios_zip
    note: "Airline Pilots Deluxe BIOS. Required by the two Airline Pilots entries."
    source_ref: "core/hw/naomi/naomi_roms.cpp:29-37, core/hw/naomi/naomi_roms.cpp:1000, core/hw/naomi/naomi_roms.cpp:1032"
    contents:
      - name: "epr-21802.ic27"
        description: Export
        size: 2097152
        crc32: "a77c6b1c"
      - name: "epr-21801.ic27"
        description: USA
        size: 2097152
        crc32: "a21bef24"

  - name: "f355bios.zip"
    path: "dc/f355bios.zip"
    standalone_path: "f355bios.zip"
    system: sega-naomi
    required: false
    category: bios_zip
    note: "Ferrari F355 Challenge twin BIOS. Required by the three twin entries."
    source_ref: "core/hw/naomi/naomi_roms.cpp:49-59, core/hw/naomi/naomi_roms.cpp:1887, core/hw/naomi/naomi_roms.cpp:1926, core/hw/naomi/naomi_roms.cpp:1965"
    contents:
      - name: "epr-22851.ic27"
        description: Export
        size: 2097152
        crc32: "62483677"
      - name: "epr-22850.ic27"
        description: USA
        size: 2097152
        crc32: "28aa539d"
      - name: "epr-22849.ic27"
        description: Japan
        size: 2097152
        crc32: "121e009c"

  - name: "f355dlx.zip"
    path: "dc/f355dlx.zip"
    standalone_path: "f355dlx.zip"
    system: sega-naomi
    required: false
    category: bios_zip
    note: "Ferrari F355 Challenge deluxe BIOS. Required by f355."
    source_ref: "core/hw/naomi/naomi_roms.cpp:60-74, core/hw/naomi/naomi_roms.cpp:1843"
    contents:
      - name: "epr-21864.ic27"
        description: Export
        size: 2097152
        crc32: "12ed7c66"
      - name: "epr-21863.ic27"
        description: USA
        size: 2097152
        crc32: "0615a4d1"
      - name: "epr-21862.ic27"
        description: Japan
        size: 2097152
        crc32: "1f630716"

  - name: "hod2bios.zip"
    path: "dc/hod2bios.zip"
    standalone_path: "hod2bios.zip"
    system: sega-naomi
    required: false
    category: bios_zip
    note: "The House of the Dead 2 BIOS. Required by the four hotd2 entries."
    source_ref: "core/hw/naomi/naomi_roms.cpp:75-85, core/hw/naomi/naomi_roms.cpp:2203, core/hw/naomi/naomi_roms.cpp:2241, core/hw/naomi/naomi_roms.cpp:2279, core/hw/naomi/naomi_roms.cpp:2317"
    contents:
      - name: "epr-21331.ic27"
        description: Export
        size: 2097152
        crc32: "065f8500"
      - name: "epr-21330.ic27"
        description: USA
        size: 2097152
        crc32: "9e3bfa1b"
      - name: "epr-21329.ic27"
        description: Japan
        size: 2097152
        crc32: "d99e5b9b"

  # -------------------------------------------------------
  # Sega NAOMI 2
  # -------------------------------------------------------
  - name: "naomi2.zip"
    path: "dc/naomi2.zip"
    standalone_path: "naomi2.zip"
    system: sega-naomi2
    required: true
    category: bios_zip
    note: "NAOMI 2 system BIOS archive. Every game whose bios field is naomi2 aborts without it."
    source_ref: "core/hw/naomi/naomi_roms.cpp:182-202, core/hw/naomi/naomi_cart.cpp:818-819, core/hw/naomi/naomi_cart.cpp:196-207"
    contents:
      - name: "epr-23605c.ic27"
        description: Japan
        size: 2097152
        crc32: "297ea6ed"
      - name: "epr-23605b.ic27"
        description: Japan
        size: 2097152
        crc32: "3a3242d4"
      - name: "epr-23607c.ic27"
        description: USA
        size: 2097152
        crc32: "750e254b"
      - name: "epr-23607b.ic27"
        description: USA
        size: 2097152
        crc32: "f308c5e9"
      - name: "epr-23608c.ic27"
        description: Export
        size: 2097152
        crc32: "6ef1dd8e"
      - name: "epr-23608b.ic27"
        description: Export
        size: 2097152
        crc32: "a554b1e3"
      - name: "epr-23609b.ic27"
        description: Korea
        size: 2097152
        crc32: "99e3751f"
      - name: "epr-23605c_multi.ic27"
        description: Multi-region
        size: 2097152
        crc32: "353fdbcd"

  # -------------------------------------------------------
  # Sega Atomiswave
  # -------------------------------------------------------
  - name: "awbios.zip"
    path: "dc/awbios.zip"
    standalone_path: "awbios.zip"
    system: sega-atomiswave
    required: true
    category: bios_zip
    note: "Atomiswave system BIOS archive. The first 64 KB of bios0.ic23 are mapped. Every Atomiswave game aborts without it."
    source_ref: "core/hw/naomi/naomi_roms.cpp:38-48, core/hw/naomi/naomi_cart.cpp:196-207"
    contents:
      - name: "bios0.ic23"
        size: 131072
        crc32: "719b2b0b"

  # -------------------------------------------------------
  # Sega System SP
  # -------------------------------------------------------
  - name: "segasp.zip"
    path: "dc/segasp.zip"
    standalone_path: "segasp.zip"
    system: sega-systemsp
    required: true
    category: bios_zip
    note: "System SP BIOS archive. The USA and Export regions also load a default motherboard EEPROM from it. Every game whose bios field is segasp aborts without it."
    source_ref: "core/hw/naomi/naomi_roms.cpp:203-218, core/hw/naomi/naomi_cart.cpp:820-821, core/hw/naomi/naomi_cart.cpp:126-139"
    contents:
      - name: "epr-24328a.ic50"
        size: 2097152
        crc32: "03ec3805"
      - name: "mb_eeprom_us.ic54s"
        description: USA
        size: 128
        crc32: "4186d7ab"
      - name: "mb_eeprom_exp.ic54s"
        description: Export
        size: 128
        crc32: "947ddfad"

platform_details:
  dreamcast:
    bios_size: 2097152
    flash_size: 131072
    ram_size: 16777216
    hle_available: true
    source_ref: "core/emulator.cpp:456-462"

  naomi:
    bios_size: 2097152
    sram_size: 32768
    ram_size: 33554432
    hle_available: false
    source_ref: "core/emulator.cpp:463-469"

  naomi2:
    bios_size: 2097152
    sram_size: 32768
    ram_size: 33554432
    hle_available: false
    source_ref: "core/emulator.cpp:470-477"

  atomiswave:
    bios_size: 131072
    sram_size: 131072
    ram_size: 16777216
    hle_available: false
    source_ref: "core/emulator.cpp:478-484"

  systemsp:
    bios_size: 2097152
    sram_size: 131072
    ram_size: 33554432
    hle_available: false
    source_ref: "core/emulator.cpp:485-491"