wtf is bluemsx-libretro?

blueMSX-libretro is a plugin that lets you play games and software from the MSX family of computers and several related 1980s consoles, ColecoVision, the SEGA SG-1000, Spectravideo, and a few others, through libretro-compatible frontends like RetroArch. Think of it as a virtual time machine for old games that originally came on cartridges, cassette tapes, or floppy disks. Under the hood, the core recreates the hardware of these systems so your computer thinks it's running the original machine. It ships with freely redistributable system files (C-BIOS) that let most cartridge games run right away without hunting down copyrighted BIOS ROMs. For other machine types, you'd need the original BIOS files. The emulator handles a variety of file formats: disk images, cassette files, and cartridge ROMs, and you can swap multi-disk games at runtime or attach hard disk images via an optional IDE controller. This is aimed at retro gaming enthusiasts, hobbyists, and anyone who wants to relive or discover games from the MSX era. If you grew up playing ColecoVision or want to try MSX games that never got a re-release, this lets you do that on modern hardware with gamepad support, on-screen keyboards, and adjustable settings like region timing and sprite flicker reduction. What's notable is the project's commitment to determinism, every emulation run produces identical results across different operating systems and processors, with no floating-point math or platform-dependent behavior. This matters for features like netplay (online multiplayer) and tool-assisted speedruns, where exact reproducibility is essential. The savestate system is also byte-stable, meaning saved games can be verified with hashes for cheat-proof online play. The codebase is written in strict C89, which keeps it portable to older compilers.