MESAx8 - Minimal Extensible System Architecture x8

I'll make a more detailed README in the near future, but for now, this repository is mainly a host of files for people who want to have a look at my progress on an 8-bit CPU design.

Files Overview

• instructions.txt — Contains my current proposal for the Instruction Set Architecture (ISA).
• cpu.circ — The main Logisim file containing all the hardware schematics.

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Schematics Breakdown (cpu.circ)

Here is a quick overview of what you will find inside the Logisim project, as it contains both current 8-bit components and remnants of an older 4-bit design:

Current 8-bit Architecture:

• main_8bit — Currently mostly empty, but this is where the entire 8-bit CPU will eventually be assembled.
• ALU_8bit — The current 8-bit ALU design.
• add_sub_8bit — 8-bit Adder/Subtractor, used in the 8-bit ALU.
• latch_8bit — 8-bit latch, also used in the 8-bit ALU.

Basic Components & Workspace:

• adder_1bit — The fundamental building block for the math circuits.
• test — Workspace for random testing, prototyping, and debugging.

Legacy 4-bit Architecture: (Note: This project originally started as a 4-bit CPU. I even have an emulator for it in another repository on my GitHub profile.)

• main_4bit — Remnant of the original 4-bit CPU top-level design.
• ALU_4bit — The complete legacy 4-bit ALU.
• adder_4bit — Used in the 4-bit ALU.
• comp_4bit — Comparator, used in the 4-bit ALU.
• add_sub_4bit — Adder/Subtractor, used in the 4-bit ALU.

Follow the Progress

I'll be documenting the development process - design decisions, schematics, and lessons learned - on my blog at www.favoslav.cz/blog. If you're interested in the deeper reasoning behind the architecture choices, that's the place to follow along.