A TOY-8 Circuitry Simulation Algorithm

Abstract

While visual learning resources for many topics in introductory-level computer science abound, visualizations of the circuit-level workings of computer architecture are conspicuously absent from most curricula. Robert Sedgewick and Kevin Wayne’s imaginary 8-bit TOY microprocessor provides an ideal model for which to build an interactive visualizer to fill this gap. Previous work with TOY visualization has produced a proven method for graphical simulation but a non-ideal implementation for interactive purposes. We aim to fill that gap with an interactive, portable applet that simulates electric flow through circuit switch diagrams. We begin with a Scalable Vector Graphics file representing the full TOY architecture and proceed to parse and trans- form its Arithmetic Logic Unit (ALU) portion to create a working, interactive browser-side graphical simulation of a combinational digital electronic circuit. In contrast to previous work, we face additional challenges in the form of in- consistent data and greater scale and complexity of circuitry. In traversing the virtual graph representation of our circuit diagram, we also take a novel approach of using a hybrid depth-first-breadth-second search that guarantees deterministic traversal of intersections. We intend our procedure to be easily repurposable for extension to the full TOY architecture as well as to arbitrary circuit diagrams.