emulator: Virtual Jaguar
type: libretro
core_classification: community_fork
source: "https://github.com/libretro/virtualjaguar-libretro"
upstream: "http://shamusworld.gotdns.org/git/virtualjaguar"
profiled_date: "2025-03-25"
core_version: "v2.1.0"
display_name: "Atari - Jaguar (Virtual Jaguar)"
cores:
  - virtualjaguar
systems:
  - atari-jaguar

notes: |
  Virtual Jaguar embeds all BIOS ROMs directly in the source code as C arrays
  (bin2c generated). No external BIOS files are loaded at runtime. The core
  selects between K-series and M-series boot ROMs based on vjs.biosType,
  then copies 0x20000 bytes to jagMemSpace + 0xE00000 (libretro.c:902-904).

  The "BIOS" core option (virtualjaguar_bios, disabled by default) controls
  whether the embedded boot ROM is executed at startup. When enabled, the
  boot ROM entry point is copied to jaguarMainRAM (jaguar.c:644-645).
  When disabled, jaguarRunAddress is written directly, skipping the boot
  animation. Either way the embedded ROM data is always present in memory.

  The jagBootPath and CDBootPath fields in VJSettings exist in the struct
  (settings.h:36-37) but are never populated or used in the libretro port.
  No call to RETRO_ENVIRONMENT_GET_SYSTEM_DIRECTORY or fopen for BIOS files.

  Jaguar CD emulation: the CD boot ROM (jaguarCDBootROM, 0x40000 bytes) is
  also embedded but Jaguar CD support is incomplete in this core. The
  cdrom.c references "CD BIOS" in comments only.

  No external BIOS files are required or loaded by this core.

files: []

analysis:
  embedded_bios:
    k_series_boot_rom:
      source_file: src/jagbios.c
      header: src/jagbios.h
      symbol: jaguarBootROM
      size: 131072  # 0x20000, 128 KB
      description: "Jaguar K-series boot ROM"
      filedb_crc: "0xFB731AAA"
      filedb_name: "[BIOS] Atari Jaguar (World)"

    m_series_boot_rom:
      source_file: src/jagbios2.c
      header: src/jagbios2.h
      symbol: jaguarBootROM2
      size: 131072  # 0x20000, 128 KB
      description: "Jaguar M-series boot ROM"

    cd_boot_rom:
      source_file: src/jagcdbios.c
      header: src/jagcdbios.h
      symbol: jaguarCDBootROM
      size: 262144  # 0x40000, 256 KB
      description: "Jaguar CD boot ROM"
      filedb_crc: "0x687068D5"
      filedb_name: "[BIOS] Atari Jaguar CD (World)"

    stubulator_93:
      source_file: src/jagstub1bios.c
      header: src/jagstub1bios.h
      symbol: jaguarDevBootROM1
      size: 131072  # 0x20000, 128 KB
      description: "Jaguar Stubulator '93 dev BIOS"
      filedb_crc: "0xE60277BB"
      filedb_name: "[BIOS] Atari Jaguar Stubulator '93 (World)"

    stubulator_94:
      source_file: src/jagstub2bios.c
      header: src/jagstub2bios.h
      symbol: jaguarDevBootROM2
      size: 131072  # 0x20000, 128 KB
      description: "Jaguar Stubulator '94 dev BIOS"
      filedb_crc: "0x8D15DBC6"
      filedb_name: "[BIOS] Atari Jaguar Stubulator '94 (World)"

    dev_cd_boot_rom:
      source_file: src/jagdevcdbios.c
      header: src/jagdevcdbios.h
      symbol: jaguarDevCDBootROM
      size: 262144  # 0x40000, 256 KB
      description: "Jaguar Developer CD boot ROM"
      filedb_crc: "0x55A0669C"
      filedb_name: "[BIOS] Atari Jaguar Developer CD (World)"

  bios_type_enum:
    source_ref: "settings.h:46"
    values:
      - BT_K_SERIES
      - BT_M_SERIES
      - BT_STUBULATOR_1
      - BT_STUBULATOR_2

  core_option:
    key: virtualjaguar_bios
    label: "BIOS"
    description: "Use the Jaguar BIOS, required for some games."
    default: disabled
    source_ref: "libretro_core_options.h:123"

  bios_loading:
    mechanism: embedded
    load_address: "0xE00000"
    load_size: "0x20000"
    source_ref: "libretro.c:902-904"
    selection_logic: "biosType == BT_K_SERIES ? jaguarBootROM : jaguarBootROM2"
    external_loading: false
    notes: |
      jagBootPath and CDBootPath struct fields are never set in the libretro
      port. The standalone Virtual Jaguar GUI uses them but that code path
      is not compiled into the libretro core.