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Little Man Computer

Description
How to use

This tool shows the working of a computer CPU using the Little Man Computer Model (LMC).

Download

.xls file (84 KB) or .zip file (34 KB)

What is the Little Man Computer ?

The Little Man Computer was created by Dr. Stuart Madnick of MIT  as a model for teaching the workings of a CPU. The LMC models the working of a modern CPU, but is still simple enough to be understood and programmed by high school students.

A full description of the Little Man Computer can be read at this Wikipedia page.

I first came across this tool in Dr. Irv Englander's book, The Architecture of Computer Hardware and System Software: An Information Technology Approach. In this book, Dr. Englander points out that the power of the computer essentially comes from speed and not from complexity. The Little Man Computer is a good illustration of this.

About the tool

The tool is an animated model of the  LMC. It consists of a CPU model, programme editor, assembler and loader. Macros must be enabled to allow it to run.  Animated gifs used to show the working of the LMC are courtesy www.cybergifs.com.

The parts of the LMC are shown in this image.
To aid the user in understanding the LMC, the tool is pre-loaded with a simple programme for adding 2 numbers. More programmes can be obtained by a search on the internet. Currently the programme does not support labels in programming, these can be added if there is are user requests.

This tool also illustrates the concepts given the Macro Overdose tip: most processing is performed in Excel itself through Data Validation and Conditional Formatting, the macros are used for animation and other functions which cannot be done using Excel features alone.

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