{
  "commit": "d38cd580364b2c788e633b9e51c15e1668f726c0",
  "count": 1,
  "generated_at": "2026-11-03T13:36:34Z",
  "items": [
    {
      "id": "fceumm",
      "profile": {
        "core_classification": "community_fork",
        "core_version": null,
        "cores": [
          "fceumm"
        ],
        "display_name": "Nintendo - NES / Famicom (FCEUmm)",
        "emulator": "FCEUmm",
        "files": [
          {
            "description": "FDS BIOS ROM",
            "name": "disksys.rom",
            "note": "Loaded at 0xE000, mapped as 8 KB PRG bank 0. Load fails if missing or short read.",
            "required": true,
            "size": 8192,
            "source_ref": "src/fds.c:680-715 (FDSLoad), src/general.c:65-67 (FCEUMKF_FDSROM)",
            "system": "nintendo-fds",
            "validation": [
              "size"
            ]
          },
          {
            "description": "Game Genie add-on cartridge ROM",
            "name": "gamegenie.nes",
            "note": "iNES format ROM (4 KB PRG + 256 bytes CHR). Core option disabled by default. Only applies to cartridge games.",
            "required": false,
            "source_ref": "src/cart.c:401-455 (FCEU_OpenGenie), src/general.c:61-63 (FCEUMKF_GGROM)",
            "system": "nintendo-nes"
          },
          {
            "description": "External NES color palette",
            "name": "nes.pal",
            "note": "RGB triplets (64 standard or 512 with de-emphasis). Only loaded when palette core option is set to Custom.",
            "required": false,
            "source_ref": "src/palette.c:170-200 (FCEU_LoadGamePalette), src/general.c:69-71 (FCEUMKF_PALETTE), src/drivers/libretro/libretro.c:1992-2001",
            "system": "nintendo-nes"
          }
        ],
        "notes": "FCEUmm (FCE Ultra mappers modified) is a NES/Famicom emulator forked from\nFCEU Ultra by CaH4e3. FDS games require the FDS BIOS ROM (disksys.rom).\nGame Genie emulation requires gamegenie.nes when the core option is enabled.\nAn external palette file (nes.pal) overrides the built-in palette when the\ncore option is set to Custom.\n\nFile path construction: src/general.c FCEU_MakeFName() joins the system\ndirectory with each filename directly - no subdirectories.\n",
        "profiled_date": "2026-03-23",
        "source": "https://github.com/libretro/libretro-fceumm",
        "source_commit": "ac0d00a7fc01166f84c7bac01d1084ebfd2b865e",
        "systems": [
          "nintendo-nes",
          "nintendo-fds"
        ],
        "type": "libretro",
        "upstream": "https://sourceforge.net/projects/fceumm/",
        "version_basis": {
          "kind": "none"
        }
      }
    }
  ],
  "kind": "emulators",
  "schema_version": 1
}