excelcpu

A working 16-bit CPU built inside Excel spreadsheets, with a ROM file, an instruction set description and an assembler script. A fun project for learning how CPUs work.

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Overview

This repository contains a working 16-bit CPU built inside Excel spreadsheets. The main workbook has 16 general purpose registers, 128KB of RAM and a 128x128 display. A separate ROM workbook is read by the CPU, another workbook describes the instruction set, and a Python script compiles programs written in the Excel-ASM16 language. Sample programs are included. Iterative calculation must be enabled with maximum iterations set to 1.

Key features

  • 16-bit CPU with 16 registers, 128KB RAM and a 128x128 display
  • ROM workbook and instruction set workbook
  • Python compiler for the Excel-ASM16 assembly language
  • Sample programs and a Notepad++ language file

Best for

Curious learners who want to see how a CPU works by inspecting it cell by cell in Excel. It needs iterative calculation turned on and runs at spreadsheet speed.

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InkboxSoftware/excelCPU
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Guo-astro/excelcpu
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4.8k
Category
Learning, interviews and curated lists
License
CC0-1.0
Forked
2025-12-03
Sync status
In syncLast synced 2026-09-29