emulator: NeoCD
type: libretro
source: "https://github.com/libretro/neocd_libretro"
profiled_date: "2026-03-18"
core_version: "2019"
display_name: "SNK - Neo Geo CD (NeoCD)"
systems:
  - snk-neogeo-cd

notes: |
  NeoCD is a dedicated SNK Neo Geo CD emulator. It supports Front Loader,
  Top Loader, and CDZ hardware variants. BIOS files go in {system_dir}/neocd/
  subdirectory (src/path.cpp:7, src/libretro_bios.cpp:76-81).

  The core scans the neocd/ directory for any .rom or .bin file (also inside
  .zip archives), reads the first 512 bytes, and identifies the BIOS type by
  binary pattern matching at fixed ROM addresses (src/bios.cpp:168-208).
  Filenames listed in the .info are conventional but not enforced by the core.

  Three hardware families are detected: Front Loader (NeoCD), Top Loader
  (NeoCD), and CDZ. Modified BIOS variants are also recognized: SMKDan 0.07,
  SMKDan 0.07b, Universe BIOS 3.2, and Universe BIOS 3.3. The core applies
  speed hack patches and CD recognition patches at load time for each type
  (src/bios.cpp:209-280).

  The Y-ZOOM ROM (ng-lo.rom / 000-lo.lo) is a sprite zoom lookup table loaded
  separately (src/memory.h:22, YZOOMROM_SIZE = 0x10000 = 65536 bytes). It is
  optional but improves sprite scaling accuracy.

  All firmware entries are marked optional in the .info (any single valid BIOS
  is sufficient). The core presents detected BIOSes as a dropdown in the core
  options menu, sorted alphabetically by description.

  BIOS ROM size: 524288 bytes (0x80000, src/memory.h:16).
  Y-ZOOM ROM size: 65536 bytes (0x10000, src/memory.h:22).

files:
  # Front Loader BIOS (NeoCD original front-loading unit)
  - name: neocd_f.rom
    dest: neocd/neocd_f.rom
    system: snk-neogeo-cd
    required: false
    size: 524288
    note: "Front Loader BIOS, official NeoCD format"
    source_ref: "retroarch/libneocd_libretro.info:15 (firmware0)"

  # Front Loader BIOS, SMKDan custom
  - name: neocd_sf.rom
    dest: neocd/neocd_sf.rom
    system: snk-neogeo-cd
    required: false
    size: 524288
    note: "Front Loader BIOS, SMKDan custom"
    source_ref: "retroarch/libneocd_libretro.info:18 (firmware1)"

  # Top Loader BIOS (NeoCD top-loading unit)
  - name: neocd_t.rom
    dest: neocd/neocd_t.rom
    system: snk-neogeo-cd
    required: false
    size: 524288
    note: "Top Loader BIOS, official NeoCD format"
    source_ref: "retroarch/libneocd_libretro.info:21 (firmware2)"

  # Top Loader BIOS, SMKDan custom
  - name: neocd_st.rom
    dest: neocd/neocd_st.rom
    system: snk-neogeo-cd
    required: false
    size: 524288
    note: "Top Loader BIOS, SMKDan custom"
    source_ref: "retroarch/libneocd_libretro.info:24 (firmware3)"

  # CDZ BIOS (Neo Geo CDZ, last revision)
  - name: neocd_z.rom
    dest: neocd/neocd_z.rom
    system: snk-neogeo-cd
    required: false
    size: 524288
    note: "CDZ BIOS, official NeoCD format"
    source_ref: "retroarch/libneocd_libretro.info:27 (firmware4)"

  # CDZ BIOS, SMKDan custom
  - name: neocd_sz.rom
    dest: neocd/neocd_sz.rom
    system: snk-neogeo-cd
    required: false
    size: 524288
    note: "CDZ BIOS, SMKDan custom"
    source_ref: "retroarch/libneocd_libretro.info:30 (firmware5)"

  # Y-ZOOM ROM (sprite zoom lookup table)
  - name: ng-lo.rom
    dest: neocd/ng-lo.rom
    system: snk-neogeo-cd
    required: false
    size: 65536
    note: "Y-ZOOM ROM, NeoCD format"
    source_ref: "retroarch/libneocd_libretro.info:33 (firmware6)"

  # Y-ZOOM ROM, MAME naming
  - name: 000-lo.lo
    dest: neocd/000-lo.lo
    system: snk-neogeo-cd
    required: false
    size: 65536
    note: "Y-ZOOM ROM, MAME naming (same content as ng-lo.rom)"
    source_ref: "retroarch/libneocd_libretro.info:36 (firmware7)"

  # Front Loader BIOS, MAME naming
  - name: front-sp1.bin
    dest: neocd/front-sp1.bin
    system: snk-neogeo-cd
    required: false
    size: 524288
    note: "Front Loader BIOS, MAME naming (same content as neocd_f.rom)"
    source_ref: "retroarch/libneocd_libretro.info:39 (firmware8)"

  # Top Loader BIOS, MAME naming
  - name: top-sp1.bin
    dest: neocd/top-sp1.bin
    system: snk-neogeo-cd
    required: false
    size: 524288
    note: "Top Loader BIOS, MAME naming (same content as neocd_t.rom)"
    source_ref: "retroarch/libneocd_libretro.info:42 (firmware9)"

  # CDZ BIOS, MAME naming
  - name: neocd.bin
    dest: neocd/neocd.bin
    system: snk-neogeo-cd
    required: false
    size: 524288
    note: "CDZ BIOS, MAME naming (same content as neocd_z.rom)"
    source_ref: "retroarch/libneocd_libretro.info:45 (firmware10)"

  # Universe BIOS for CD systems
  - name: uni-bioscd.rom
    dest: neocd/uni-bioscd.rom
    system: snk-neogeo-cd
    required: false
    size: 524288
    note: "Universe BIOS CD, third-party multi-region BIOS (hack)"
    source_ref: "retroarch/libneocd_libretro.info:48 (firmware11)"