v2026.04.02/emulators/emux_chip8.yml

emulator: "emux (CHIP-8)"
type: libretro
core_classification: official_port
source: "https://github.com/libretro/emux"
upstream: "https://github.com/sronsse/emux"
profiled_date: "2026-03-23"
core_version: "0.1"
display_name: "CHIP-8 (Emux CHIP-8)"
cores:
  - emux_chip8
systems:
  - chip8

notes: |
  emux is a multi-system emulator supporting CHIP-8, Game Boy, NES, and
  Sega Master System as separate libretro cores. The CHIP-8 core
  (emux_chip8) does not require any external BIOS or firmware files.

  The CHIP-8 architecture has no real BIOS. The standard font/character
  set (hex digits 0-F, 5 bytes each = 80 bytes) is hardcoded in
  mach/chip8.c:40-57 as the char_mem[] array. On reset, this font data
  is copied into the beginning of the 4 KB RAM (address 0x000-0x04F)
  via memcpy in chip8_reset() at mach/chip8.c:105.

  ROM loading: the game ROM is loaded via file_open(PATH_DATA, ...) in
  chip8_init() at mach/chip8.c:68-74. On reset, ROM contents are copied
  into RAM starting at address 0x200 (mach/chip8.c:113). The core
  accepts .ch8, .bin, and .rom extensions (libretro/Makefile.rules:20).

  Memory map from mach/chip8.c:17-20:
    0x000-0x04F  font/character data (hardcoded)
    0x050-0x1FF  unused
    0x200-0xFFF  program ROM + working RAM

  The libretro frontend retrieves the system directory via
  RETRO_ENVIRONMENT_GET_SYSTEM_DIRECTORY (libretro/libretro.c:34) but
  only uses it as a general config path, not for BIOS loading.

exclusion_note: "CHIP-8 has no BIOS, font data hardcoded in char_mem[]"
files: []

platform_details:
  bios_mapping:
    target: "none"
    source_ref: "mach/chip8.c:40-57, mach/chip8.c:98-115"
    note: |
      No external BIOS. The 80-byte character font is compiled into the
      binary as char_mem[] and memcpy'd into RAM[0x000] on every reset.
      This is standard CHIP-8 behavior -- all interpreters embed the font.