emulator: FCEUmm Mod
type: libretro
core_classification: community_fork
source: "https://github.com/Tippek/libretro-fceumm-mod"
upstream: "https://github.com/libretro/libretro-fceumm"
profiled_date: "2026-10-22"
source_commit: "f0ea52190427b136a51da4490e49087fe2ca2abb"
core_version: "SVN"
display_name: "Nintendo - NES / Famicom (FCEUmm Mod)"
cores:
  - "fceumm_mod"
systems: [nintendo-nes, nintendo-fds]

notes: |
  libretro-fceumm with the hardware extensions of fceux-mod (extra RAM,
  sprites, palettes and mappers). The libretro driver hands the system
  directory to FCEUI_SetBaseDirectory (src/drivers/libretro/libretro.c:2983-2984)
  and FCEU_MakeFName joins each name to it directly (src/general.c:70-97).

  The Game Genie image is named gg.rom here (src/general.c:77-79), but
  FCEU_OpenGenie runs only when FSettings.GameGenie is set
  (src/fceu.c:283-285) and nothing in the libretro driver calls
  FCEUI_SetGameGenie (src/fceu.c:551-554), so the file is never opened.

files:
  - name: "disksys.rom"
    system: nintendo-fds
    description: "FDS BIOS ROM"
    required: true
    size: 8192
    validation: [size]
    source_ref: "src/fds.c:612-650, src/general.c:80-82"
    note: "Read as one 8 KB PRG bank. A missing file or a short read fails the FDS load."

  - name: "nes.pal"
    system: nintendo-nes
    description: "External NES color palette"
    required: false
    source_ref: "src/palette.c:191-212, src/fceu.c:289-290, src/drivers/libretro/libretro.c:1674-1682, 3013-3017"
    note: "Read at every game load when present, 768 bytes of RGB triplets. Applied when the fceumm_palette option is custom."