emulator: "YabaSanshiro"
type: standalone + libretro
core_classification: official_port
source:
  libretro: "https://github.com/libretro/yabause/tree/yabasanshiro"
  standalone: "https://github.com/sydarn/yabause/tree/pi4-update"
upstream: "https://github.com/devmiyax/yabause"
profiled_date: "2026-10-24"
source_commit:
  libretro: "09ed8e5b2e97e7a848ea2514545c34c7b809e399"
  standalone: "a40dace1ae0af3ebd45848549fdf396f40e3930f"
core_version:
  libretro: "v2.6.8"
  standalone: "1.11.beta3"
display_name: "Sega - Saturn (YabaSanshiro)"
cores:
  - yabasanshiro
  - "yabasanshiro-2"
  - "yabasanshiroSA"
  - "yabasanshiro-sa"
systems:
  - sega-saturn

data_root:
  linux:
    path: "~/.yabasanshiro"
    source_ref: "yabause/src/retro_arena/main.cpp:292-301"
    note: "Created at startup. Holds backup.bin, keymapv2.json, the per-game settings files, save states and screenshots. No firmware is read from it."

notes: |
  YabaSanshiro is a Sega Saturn emulator by devmiyax, forked from Yabause.
  Requires OpenGL 3.3 or OpenGL ES 3.0.

  Saturn BIOS search order:
    1. {system}/saturn_bios.bin
    2. {system}/sega_101.bin
    3. {system}/mpr-17933.bin
  First file found wins. Real BIOS required for normal operation.
  HLE available via yabasanshiro_force_hle_bios core option (deprecated,
  debug only).

  Addon cartridges: 1M/4M RAM expansion via core option (no files needed).
  ROM cartridge and MPEG card ROM loading disabled in libretro port
  (cartpath = empty, mpegpath = NULL).

  BIOS loading: retro_load_game() at yabause/src/libretro/libretro.c:1048-1071.
  Core load: LoadBios() at yabause/src/memory.c:1353-1356, T123Load() at yabause/src/memory.h:219-289.

  Standalone: the retro_arena SDL2 front end of the sydarn/yabause
  pi4-update branch, built with -DYAB_PORTS=retro_arena. It prints version
  1.11.beta3 (yabause/CMakeLists.txt:15-18, yabause/src/config.h.in:5). It
  opens a BIOS only at the path given with -b or --bios, under any name.
  Without it biospath stays NULL and the core runs its HLE BIOS
  (yabause/src/retro_arena/main.cpp:161, yabause/src/retro_arena/main.cpp:230-234,
  yabause/src/retro_arena/main.cpp:325-328, yabause/src/yabause.c:373-388).
  The image is read through T123Load, which truncates a file above 512 KiB
  and checks nothing else (yabause/src/memory.c:1400-1403,
  yabause/src/memory.h:219-242). A -b path that cannot be read stops
  YabauseInit. The MPEG card and ROM cartridge paths stay empty, so no
  other firmware is read.

  ROCKNIX passes -b with the first of saturn_bios.bin, sega_101.bin,
  mpr-17933.bin, mpr-18811-mx.ic1, mpr-19367-mx.ic1 and stvbios.zip found
  under its BIOS folder when its use_hlebios setting is 1
  (ROCKNIX projects/ROCKNIX/packages/emulators/standalone/yabasanshiro-sa/scripts/start_yabasanshiro.sh:80-91).
  AmberELEC passes saturn_bios.bin from its BIOS folder unless HLE is
  selected (AmberELEC packages/games/emulators/yabasanshiroSA/yabasanshiro.sh:63-70).
  Both build the pi4-update tip and patch the home directory to
  /storage/.config/yabasanshiro.

files:
  - name: "saturn_bios.bin"
    system: sega-saturn
    mode: libretro
    priority: 1
    required: true
    hle_fallback: true
    note: "Primary Saturn BIOS. Any region accepted."
    source_ref: "yabause/src/libretro/libretro.c:1048"

  - name: "sega_101.bin"
    system: sega-saturn
    mode: libretro
    priority: 2
    required: false
    hle_fallback: true
    note: "Saturn BIOS v1.01 (Japan). Fallback if saturn_bios.bin missing."
    source_ref: "yabause/src/libretro/libretro.c:1052"

  - name: "mpr-17933.bin"
    system: sega-saturn
    mode: libretro
    priority: 3
    required: false
    hle_fallback: true
    note: "Saturn BIOS v1.003 (NA/EU). Last fallback."
    source_ref: "yabause/src/libretro/libretro.c:1056"