The 24-Bit CPU

This repository contains my implementation of a 24-bit CPU, building upon the 16-bit CPU I created in 2023 as part of a school project.

At the time, my understanding of CPU architecture was limited, and the 16-bit design relied on several improvised solutions. While it met the requirements of the project, I have since revisited the topic and invested significant time in researching proper CPU design principles and instruction handling.

This project represents a cleaner, more robust, and more thoughtfully designed successor to that earlier work. It incorporates the lessons I’ve learned and reflects a deeper understanding of computer architecture.

I recognize that there is still much more to explore in this field, and I welcome feedback, suggestions, and contributions to help improve this project further.

Current State

• Implements a RISC-style instruction set architecture (ISA) on a von Neumann bus architecture.
• Supports 16 MB of memory, with 14 MB available as addressable RAM and 2 MB reserved for memory-mapped I/O (MMIO) and storage.
• Provides 16 general-purpose registers (GPRs).
• Includes interrupt handling support.
• Features a 24-bit Arithmetic Logic Unit (ALU).

Plans

This project was created primarily for educational purposes, but my goal is to evolve it into a fully functional 24-bit CPU with features that make software development on it practical and enjoyable.

Planned improvements include:

• Refining the instruction set to address current limitations with immediate constants and memory access.
• For example, instructions such as LDI REA, [#0xF00000] or ADD REA, #1, REC are currently unsupported and require workarounds.
• Expanding instruction support to make operations more intuitive and efficient.
• Enhancing overall CPU functionality with features commonly found in modern educational CPU designs.
• Improving documentation and tooling to make the CPU easier to understand, use, and extend.

Docs

• How to use the compiler
• How to use the linker
• How to install the syntax highlighter
• How to use the assembly language
• CPU components explained

Requirements

• Visual Studio Code
• Python 3.10
• Logisim Evolution (latest binaries)

This Repo is actively maintained.