bnes - RetroBIOS¶
| Type | libretro |
| Source | https://github.com/libretro/bnes-libretro |
| Version | v083 |
| Profiled | 2026-03-18 |
| Cores | bnes |
| Systems | nes |
No BIOS or firmware files required. This core is self-contained.
bnes is a NES emulator based on byuu's bNES/higan v083 NES module, ported to libretro by Ryphecha. It is a lightweight, accuracy-focused NES core.
The core loads cartridge data entirely through retro_load_game with need_fullpath=false (libretro/libretro.cpp:129). ROM data is passed as a memory buffer and parsed by Cartridge::load (nes/cartridge/cartridge.cpp:18-31), which detects iNES headers (16-byte offset) and delegates to Board::load.
The PPU generates its palette from a hardcoded color table in libretro/libretro.cpp:20-37 with emphasis factor tables. No external palette file is loaded.
System::init (nes/system/system.cpp:62-66) only sets up the interface pointer and default input devices. No system ROM, BIOS, or firmware is loaded at any stage of initialization or cartridge loading.
The core does not call RETRO_ENVIRONMENT_GET_SYSTEM_DIRECTORY and has no file I/O for BIOS or firmware. FDS (Famicom Disk System) is not supported, so disksys.rom is not needed.
No external BIOS or firmware files are needed.
Generated on 2026-03-20T19:12:20Z