Bug

[ShevtsovNikita]

I found a bug when executing two commands MULH and MUL one after the other

This is correct result achieved by executing solo MULH operation:

This is correct result achieved by executing solo MUL operation:

And this is incorrect result when MUL goes after MULH:

It happens because control signal "is_mulh" and result of multiplication "mul_rd" performed in combinational logic.

So in 1st clock "is_mulh" already takes the value of MUL and "result" takes the value of lower part of "rd" when it have to keep value of high part

[jg-fossh]

The design seems to expect that signals will be held stable for at least a couple of clocks. Maybe that is expected behavior of the SERV core. @ShevtsovNikita do you have still have your testbench by any chance? I forked the project and made a quick update in a branch, but I haven't tested it. MDU Product & Handshake Alignment.