"Once upon a time, I got bored with VMIPS and decided to work on a
 *real* RISC architecture for a change. So, while taking a break one day,
 I wrote a simulator for the Single Instruction Computer. It's pretty scary.
 You can (probably) download the source here."

This directory contains the source code for sbn, an interpretative
simulator for the world's simplest computing architecture. The machine
this simulator simulates only has one instruction: Subtract and Branch
if Negative. A README file is included in the source distribution,
which contains build instructions; once you've built it, look at the
online help.