emulator: Gearcoleco
type: libretro
core_classification: official_port
source: "https://github.com/drhelius/Gearcoleco"
upstream: "https://github.com/drhelius/Gearcoleco"
profiled_date: "2026-03-23"
core_version: "1.0.0"
display_name: "Coleco - ColecoVision (Gearcoleco)"
cores:
  - gearcoleco
systems:
  - colecovision

notes: |
  ColecoVision emulator by Ignacio Sanchez (drhelius). Official port
  maintained by the upstream author. The ColecoVision BIOS ROM is required.
  Without it, the core renders a static placeholder image (kNoBiosImage from
  no_bios.h) and games do not execute.

  The libretro wrapper (libretro.cpp:293-306) tries "colecovision.rom" first,
  then falls back to "coleco.rom". Both resolve to the same LoadBios() call
  in Memory.cpp:228-259 which validates size == 0x2000 (8192 bytes) only.
  No hash check is performed.

  On reset, BIOS byte at offset 0x69 is patched for region selection:
  0x3C for NTSC, 0x32 for PAL (Memory.cpp:184-187).

  SGM (Super Game Module) expanded RAM requires no additional BIOS files.

files:
  - name: "colecovision.rom"
    aliases: ["coleco.rom"]
    system: colecovision
    required: true
    size: 8192
    validation: [size]
    source_ref: "platforms/libretro/libretro.cpp:293-306, src/Memory.cpp:228-259"