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.
Pick a small issue you can reproduce, then fix it with your AI coding agent.
Share on XLicense: CC0-1.0
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.
- Upstream
- InkboxSoftware/excelCPU
- Fork on GitHub
- Guo-astro/excelcpu
- Upstream stars
- 4.8k
- Category
- Learning, interviews and curated lists
- License
- CC0-1.0
- Forked
- 2025-12-03
- Sync status
- In syncLast synced 2026-10-20
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