emulator: RetroDream
type: libretro
source: "https://github.com/libretro/redream-next"
systems:
  - sega-dreamcast

notes: |
  Fork of the final open-source redream release (pre-relicense). Experimental
  core with no HLE BIOS -- real BIOS files are required to boot games.
  Flycast is recommended over this core for actual gameplay.

  The libretro core sets appdir to the RetroArch system directory
  (src/host/retro_host.c:216-217). boot.bin and flash.bin are loaded
  directly from appdir (src/guest/rom/boot.c:17, src/guest/rom/flash.c:30).

  The .info file declares paths as dc/boot.bin and dc/flash.bin, which means
  RetroArch resolves them under {system_dir}/dc/.

  boot.bin is validated against four known MD5 hashes at load time
  (src/guest/rom/boot.c:25-30). If validation fails, the core logs a warning
  but still attempts to run via HLE syscall hooks (bios.c:440-447).

  flash.bin is read/write -- the core saves modified flash data back to disk
  on shutdown (src/guest/rom/flash.c:197-199).

  Boot ROM size: 2 MB (0x200000). Flash ROM size: 128 KB (0x20000).

files:
  - name: "boot.bin"
    system: sega-dreamcast
    path: "dc/boot.bin"
    required: true
    size: 2097152  # 2 MB (0x200000)
    md5:
      - e10c53c2f8b90bab96ead2d368858623  # original US/EU BIOS
      - a5c6a00818f97c5e3e91569ee22416dc  # Chinese BIOS
      - 37c921eb47532cae8fb70e5d987ce91c  # Japanese BIOS
      - f2cd29d09f3e29984bcea22ab2e006fe  # revised BIOS without MIL-CD
    note: "Dreamcast boot ROM. Validated against known MD5 hashes at load."
    source_ref: "src/guest/rom/boot.c:12-80"

  - name: "flash.bin"
    system: sega-dreamcast
    path: "dc/flash.bin"
    required: true
    size: 131072  # 128 KB (0x20000)
    md5:
      - 0a93f7940c455905bea6e392dfde92a4
    note: "Dreamcast flash memory (date, time, language). Written back on shutdown."
    source_ref: "src/guest/rom/flash.c:25-35"

platform_details:
  dreamcast:
    bios_size: 2097152     # 2 MB
    flash_size: 131072     # 128 KB
    hle_available: false
    source_ref: "src/guest/rom/boot.c, src/guest/rom/flash.c"