This page illustrates the behavior of a simple stack machine specified by Nicklaus Wirth in his book Algorithms + Data Structures = Programs.
Select one of the sample programs. Then click Step to step through it.
A short description of the PL/0 virtual machine and its machine language is available on another page. [Further explanation and commentary would probably be useful, and will be provided eventually.]
Some sample programs are available; select one from the list and load it.