SachinDas246

Project Overview

The 8085 Simulator is a fully interactive environment designed to help learners understand how the Intel 8085 microprocessor executes instructions internally. The project began as a passion for low-level computing and evolved into a polished cross-platform simulator used by students and Reddit communities exploring retro CPU architecture.

The simulator supports real-time register updates, flag manipulation, memory inspection, and step-by-step execution — making it a powerful learning companion for microprocessor courses.

The Problem / Story Behind the Project

I started building the 8085 Simulator during my B.Tech in Electrical & Electronics Engineering at CUSAT. During our microprocessor lab sessions, we ran into a major timing conflict: the lab hours always overlapped with the preparation time for Decibel, our college technical fest. As a result, many of us were unable to attend the microprocessor lab regularly, and we were missing the opportunity to practically learn assembly-level programming. We only had the theory — no real hands-on experience with how the 8085 worked internally.

At that time, I was experimenting with Unity3D, so I began creating a small internal tool — just for myself and a few teammates who were also involved in the fest. The idea was simple: a lightweight simulator where we could quickly write and run 8085 instructions without needing the physical hardware setup.

But as the lab exams got closer, word spread quickly. Students across my class began using the simulator to practice instructions, understand registers, and visualize how the 8085 executed each step. That was when I realized that something I built out of necessity actually solved a deeper learning gap. So I continued improving it beyond the fest season and eventually decided to release it publicly.

Over the years, I ported the simulator to Flutter and later created a dedicated web version as well. During the COVID lockdown, when offline labs were shut down, the simulator unexpectedly became even more helpful — giving students a way to continue learning microprocessors from home.

Key Features

• Real-time Register Visualization : Watch A, B, C, D, E, H, L, SP, PC update instantly as instructions execute.

• Flag Register Updates : Zero, Carry, Sign, Parity, Auxiliary Carry flags update step-by-step.

• Instruction Execution Modes: Step execution, Run until HALT

• Cross-Platform Versions:

  • Flutter version on itch.io
  • React (Vite + Zustand) version for web

• Clean UI / Beginner Friendly:

  • Designed for students learning their first assembly programs.

Tech Stack

• Flutter Version

  • Flutter
  • Dart
  • Provider & Getx

• React Web Version

  • React + Vite
  • Zustand for global state
  • TypeScript
  • Tailwind