Spreadsheet fanatic builds a CPU within Microsoft Excel that has a display but can't run Excel or Doom — and no, it doesn't work in the cloud just yet

Excel CPU
(Image credit: Inkbox)

Microsoft Excel is well known for its versatility (it can even run first person classic shooter Doom) - but who knew the spreadsheet software could also be used to build a functioning CPU?

It might sound ridiculous, but that's precisely what a YouTuber named Inkbox has done, as demonstrated in a detailed 16-minute video. Inkbox achieved this feat without using any Visual Basic scripts or plugins, purely utilizing Excel's capabilities.

The result is a 16-bit CPU that operates within Excel at a clock rate of 3Hz, complete with 128KB of RAM, a 16-color 128x128 pixel display, and a custom assembly language. What's more, the CPU files are available on Github for anyone to try.

Excel-ASM16 assembly language

One of the most impressive aspects of this project is Inkbox's creation of a fully functioning assembly language for the Excel CPU. Named Excel-ASM16, it includes 23 different instructions and supports variables, labels, and even binary file support. These functionalities may be basic for an assembly language, but they are quite significant given the constraints of a 16-bit CPU running within Excel.

In the source video, Inkbox provides a comprehensive explanation of the functions of Excel used in the project and how they were manipulated to create a functioning 16-bit CPU. Despite the CPU's speed being no more than 3Hz, the time-lapse demonstration allows viewers to see the inner workings of the CPU.

Though the 16-bit CPU built within Excel has its limitations, it demonstrates an impressive level of technical skill and creativity on Inkbox's part. The freely shared Excel-ASM16 and its CPU, with some sample programs on Github, provide an opportunity for any like-minded Excel users to explore this unique creation for themselves.

Watch the video below:

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Via Tom's Hardware

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Wayne Williams

Wayne Williams is a freelancer writing news for TechRadar Pro. He has been writing about computers, technology, and the web for 30 years. In that time he wrote for most of the UK’s PC magazines, and launched, edited and published a number of them too.