A much better CPU i made in Digital Logic Sim Community Edition
Paste the folder called MUCH_BETTER_CPU into %appdata%\..\LocalLow\SebastianLague\Digital-Logic-Sim\Projects and open the project in DLS
Download the assembler from here and drag the file you want to compile on top of it. Alternatively, you can run main.exe with the file as an argument in a cmd window for debug info
The assembler automatically updates the project, just exit out of it and then open it again to updates it
When you download it it doesn't have a program, if you just want a test - load snake.txt