emux (CHIP-8)
emux (CHIP-8) emulates CHIP-8.
About this profile
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.
Technical 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.
No BIOS or firmware files required.
Next steps
Section titled “Next steps”- Get your files, for the setup you play on
- Every system, and the files each one needs
- When a game does not start