Zet processor is an open implementation of the so widely used IA-32 architecture (generally called x86). It is implemented in Verilog and can be synthesized for FPGAs. One of the supported development boards is the Altera DE1 Board. DE1 only has one PS/2 port so mouse is not supported on that board. But the board has many IO-ports and the mouse PS/2 pins are mapped to some of the IO pins. The picture below shows how the PS/2 hardware on the DE1.

DE1 PS/2
DE1 PS/2

I soldered this simple circuit on a experimentation board with connectors to the DE1 board and PS/2. It worked with a old PS/2 mouse, but I was not able to make it work with a newer USB mouse connected through a USB to PS/2 mouse converter. Below is a movie showing the board booting DOS, starting MS Windows 3.0 and playing some games. Only some games are playable, some are to slow and some crash.