emulator: xemu Chihiro
type: standalone
core_classification: community_fork
source: "https://github.com/Tovarichtch/xemu"
source_branch: perf-experimental
upstream: "https://github.com/xemu-project/xemu"
profiled_date: "2026-10-20"
source_commit: "0d44d803b2ad22c26c907844fe81d40fbd6ffdfa"
core_version: "0.8.134-406-g0d44d803b2"
display_name: "Sega - Chihiro (xemu Chihiro)"
cores:
  - xemu-chihiro
systems:
  - sega-chihiro
mode: standalone

notes: |
  Tovarichtch's fork of xemu that adds the Sega Chihiro machine: the media
  board, the AN2131 and its 8051 firmware, JVS, the drive boards, the card
  readers and the network board. RetroBat ships the build whose version string
  is 0.8.134-406-g0d44d803b2, the "Source code release and playtest v2" commit
  this profile is pinned to, on the perf-experimental branch
  (the one with the fork's NV2A and CPU work). Batocera builds the same fork at a later commit.

  RetroBat runs this emulator only as a Chihiro: the launcher sets the Chihiro
  path whenever the emulator is xemu-chihiro. It writes chihiro.roms.bios_path
  as bios/chihiro/chihiro_xbox_bios.bin, else bios/chihiro_xbox_bios.bin, and
  clears the media board and EEPROM paths so the emulator takes them from the
  folder of the BIOS.
  ref: emulatorLauncher Generators/Xemu.Generator.cs:48, 413-444

  A Chihiro boots its own BIOS only, never the Xbox flash or MCPX boot ROM set
  for the Xbox machine: the Chihiro BIOS is an MCPX X2 image with its boot ROM
  built in. The BIOS must be 512 KiB with the SHA-1 MAME lists, else the
  machine stays paused with an error.
  ref: system/vl.c:3110-3135, 3169-3190, hw/xbox/chihiro/chihiro.c:2280-2292

  The media board flash and the three serial EEPROMs come from the settings
  when set, else from the folder of the BIOS. The flash is tried as
  fpr21042_m29w160et.bin, fpr-23887_29lv160te.ic4, then fpr-23887.bin, each in
  that folder and then in its parent, and any size up to 4 MiB is read. The
  EEPROMs must have their exact size or they count as absent. Any of the five
  files missing keeps the machine paused with a message naming it.
  ref: hw/xbox/chihiro/chihiro.c:2259-2401, system/vl.c:3195-3241

  The Xbox EEPROM is not a file to supply for a Chihiro: chihiro_eeprom.bin is
  generated with the debug key in the data directory and written back. The VM
  snapshots, the per game saves, the DIMM system area and the card images are
  written by the emulator too. Booting an Xbox disc with this build reads the
  same files as upstream xemu (emulators/xemu.yml), which RetroBat never asks
  it to do.
  ref: system/vl.c:2978-3001

  The network firmware of the DIMM board is read only from the setting
  chihiro.roms.net_firmware_path, which RetroBat does not write. Without it the
  board reports version 3.17. Linked cabinets need it to run the network board,
  and network titles check the version it reports (OutRun 2 SP, Gundam).
  ref: hw/xbox/chihiro/chihiro.c:363-400, 491-513, config_spec.yml:908-915

files:
  - name: chihiro_xbox_bios.bin
    path: "chihiro/chihiro_xbox_bios.bin"
    system: sega-chihiro
    required: true
    size: 524288
    sha1: "b700b0041af8f84835e45d1d1250247bf7077188"
    validation: [size, sha1]
    description: "Chihiro BIOS"
    note: "RetroBat also looks for it at the root of the bios folder. The other Chihiro files are then read from the same folder."
    source_ref: "source hw/xbox/chihiro/chihiro.c:2280-2292, source system/vl.c:3169-3190"

  - name: fpr21042_m29w160et.bin
    path: "chihiro/fpr21042_m29w160et.bin"
    system: sega-chihiro
    required: true
    max_size: 4194304
    validation: [size]
    description: "Media board flash ROM (SEGABOOT)"
    note: "First of the three names tried. The SEGABOOT version is read from the second megabyte and the board serial from the MBDT header at 0xFFE00."
    source_ref: "source hw/xbox/chihiro/chihiro.c:2259-2333, 485-489, source system/vl.c:3201-3214"

  - name: fpr-23887_29lv160te.ic4
    path: "chihiro/fpr-23887_29lv160te.ic4"
    system: sega-chihiro
    required: false
    max_size: 4194304
    validation: [size]
    aliases: [fpr-23887.bin]
    description: "Media board flash ROM, later revision"
    note: "Read in place of fpr21042_m29w160et.bin when that one is absent, under either name."
    source_ref: "source hw/xbox/chihiro/chihiro.c:2320-2332"

  - name: ic10_g24lc64.bin
    path: "chihiro/ic10_g24lc64.bin"
    system: sega-chihiro
    required: true
    size: 8192
    validation: [size]
    description: "Base board QC EEPROM"
    source_ref: "source hw/xbox/chihiro/chihiro.c:2336-2401, source system/vl.c:3215-3217"

  - name: pc20_g24lc64.bin
    path: "chihiro/pc20_g24lc64.bin"
    system: sega-chihiro
    required: true
    size: 8192
    validation: [size]
    description: "Base board SC EEPROM"
    source_ref: "source hw/xbox/chihiro/chihiro.c:2336-2401, source system/vl.c:3218-3220"

  - name: ic11_24lc024.bin
    path: "chihiro/ic11_24lc024.bin"
    system: sega-chihiro
    required: true
    size: 128
    validation: [size]
    description: "Base board configuration EEPROM"
    source_ref: "source hw/xbox/chihiro/chihiro.c:2336-2401, source system/vl.c:3221-3223"

  - name: ver1305.bin
    system: sega-chihiro
    required: false
    description: "DIMM board network firmware 13.05"
    note: "Opened only from the path set in the settings. Its version is the word after the FIRM_VERSION is here! mark."
    source_ref: "source hw/xbox/chihiro/chihiro.c:363-400, 491-513, source hw/xbox/chihiro/chihiro-netboard.c:1257-1270"