emulator: yabause
type: libretro
core_classification: community_fork
source: "https://github.com/libretro/yabause"
upstream: "https://github.com/Yabause/yabause"
profiled_date: "2026-03-25"
core_version: "v0.9.15"
display_name: "Sega - Saturn (Yabause)"
cores:
  - yabause
systems:
  - sega-saturn

notes: |
  Yabause is a software-rendered Sega Saturn emulator. Upstream project is
  dead; libretro port maintained by the community on the master branch of
  libretro/yabause.

  Saturn BIOS search order:
    1. {system}/saturn_bios.bin
    2. {system}/sega_101.bin
    3. {system}/mpr-17933.bin
  First file found wins. HLE BIOS available via yabause_force_hle_bios core
  option (reduced compatibility). Multi-disc (m3u) requires real BIOS.

  Addon cartridges: 1M/4M RAM expansion via core option (no files needed).
  ROM cartridge loading, SH1 ROM (CD Block LLE), and MPEG card ROM are
  standalone-only features disabled in the libretro port.

  BIOS loading: libretro.c retro_load_game() lines 1035-1049.
  Core load: memory.c LoadBios() line 1260, T123Load() memory.h lines 196-264.

files:
  - name: "saturn_bios.bin"
    system: sega-saturn
    required: true
    hle_fallback: true
    max_size: 524288
    validation: [max_size]
    note: "Primary Saturn BIOS. Any region accepted."
    source_ref: "libretro.c:1035"

  - name: "sega_101.bin"
    system: sega-saturn
    region: [japan]
    required: false
    hle_fallback: true
    max_size: 524288
    validation: [max_size]
    note: "Saturn BIOS v1.01 (Japan). Fallback if saturn_bios.bin missing."
    source_ref: "libretro.c:1039"

  - name: "mpr-17933.bin"
    system: sega-saturn
    region: [north-america, europe]
    required: false
    hle_fallback: true
    max_size: 524288
    validation: [max_size]
    note: "Saturn BIOS (NA/EU). Last fallback."
    source_ref: "libretro.c:1043"