LIMESTONE

An MSX emulator covering the MSX1, MSX2, and MSX2+. The Z80 runs against the TMS9918A on the MSX1, the V9938 on the MSX2, and the V9958 on the MSX2+, with every display mode, both sprite modes, the command engine, and 128 KB of video RAM. The V9958 adds hardware horizontal scrolling and the colour-difference screens that show far more colours than its palette holds, so a game written for it scrolls the way it does on the machine it was made for. Software asks the chip which one it is before using any of that, so the model is chosen deliberately rather than guessed.

The beeper, the AY-3-8910, and a Konami SCC cartridge are synthesised band-limited into a single mix, joined on the MSX2 and MSX2+ by MSX-MUSIC, a YM2413 ported from ymfm and checked against it sample for sample across every instrument, every envelope rate, both waveforms, and all five percussion voices. Each source has its own volume control, and the mix counts only the chips the machine and the cartridge actually have, so a plain cartridge is never quietened to make room for one that is not there.

Cartridges are recognised by checksum against a database built out of MAME's software lists, guessed from the image when they are not in it, or forced by hand: Normal, 32 Kb, 48 Kb, Konami, Konami SCC, and ASCII 8 Kb and 16 Kb. C-BIOS is built in, so no system ROM is needed, and the MSX2's clock and CMOS are offered to the frontend so they outlive the session. Keyboard and joystick input, save states, and battery-backed cartridge saves round it out.

Available on Windows, Linux, macOS, Android, iOS, and WebAssembly. Limestone is plain, portable C11 with no exotic dependencies, so a port to video game consoles is well within reach. Contact us if that is of interest.

Retro City Skyline

Limestone in Action

Commercial games running unmodified on Limestone, shown to demonstrate compatibility.

Knightmare running on Limestone
Knightmare © 1986 Konami
Metal Gear running on Limestone
Metal Gear © 1987 Konami
The Treasure of Usas running on Limestone
The Treasure of Usas © 1987 Konami
Zanac running on Limestone
Zanac © 1986 Compile / Pony Canyon

Limestone Options

Third-Party Software