https://github.com/debjitbis08/sim8085
Fast, accurate, and offline-capable Intel 8085 simulator with assembler and debugger. Works on desktop and mobile, no installation needed.
https://github.com/debjitbis08/sim8085
8080 8085 assembler electronics emulator engineering simulator students
Last synced: 18 days ago
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Fast, accurate, and offline-capable Intel 8085 simulator with assembler and debugger. Works on desktop and mobile, no installation needed.
- Host: GitHub
- URL: https://github.com/debjitbis08/sim8085
- Owner: debjitbis08
- License: bsd-3-clause
- Created: 2013-01-30T09:48:27.000Z (about 13 years ago)
- Default Branch: master
- Last Pushed: 2026-01-24T16:53:15.000Z (19 days ago)
- Last Synced: 2026-01-25T05:56:34.242Z (18 days ago)
- Topics: 8080, 8085, assembler, electronics, emulator, engineering, simulator, students
- Language: JavaScript
- Homepage: https://www.sim8085.com
- Size: 14.7 MB
- Stars: 129
- Watchers: 7
- Forks: 45
- Open Issues: 2
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Funding: .github/FUNDING.yml
- License: LICENSE
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README
# Sim8085
[](https://github.com/debjitbis08/sim8085/blob/master/LICENSE) [](https://www.sim8085.com) [](https://github.com/debjitbis08/sim8085/stargazers)
Sim8085 is a modern web-based development environment for the Intel 8085 microprocessor. It includes a graphical editor, assembler, and debugger designed to help students, educators, and enthusiasts explore 8085 assembly programming.
🖥️ Try it now at [sim8085.com](https://www.sim8085.com)
---
## ✨ Features
- 📝 **Syntax-highlighted editor** for writing 8085 assembly code.
- 🐞 **Interactive debugger** with:
- Step-by-step execution
- Flag and register updates
- Visual memory inspection
- ⚙️ **Assembler with smart error messages**, help fix common problems quickly.
- 🧠 **Interrupt system** that closely matches how the 8085 handles interrupts.
- ♾️ **Supports long-running programs** (e.g., waveform generators or infinite loops), safely handled in-browser.
- ⏱️ **Instruction Timing Mode** to simulate real-time delays.
- 🧹 **Built-in code formatter** that aligns mnemonics, operands, and comments into neatly spaced columns.
- 🚄 **Near-native performance**, powered by a C-based simulator compiled to highly optimized JavaScript via Emscripten.
- 📱 **Mobile-friendly** and works great in modern mobile browsers.
- 💾 **Offline support**: Once loaded, Sim8085 continues to work even without an internet connection thanks to full PWA support.
- 📦 **Installable as an app**: Add Sim8085 to your home screen or desktop like a native app, no App Store needed.
---
## 🖼️ Screenshot
---
## 🛠️ Development Setup
### 📦 Requirements
- [Emscripten SDK](https://emscripten.org/docs/getting_started/downloads.html)
- Node.js ≥ 22.x and [pnpm](https://pnpm.io)
### 🚧 Steps
1. **Install Emscripten** (follow [official instructions](https://emscripten.org/docs/getting_started/downloads.html)). You need this only if you are working on the instruction simulator code (`src/core/8085.c`).
2. Clone this repo and install dependencies:
```bash
pnpm install
```
3. Start the development server:
```bash
pnpm dev
```
---
### 🔧 Building the Emulator (C to JS)
If you make changes in `src/core/8085.c`:
1. Build the updated simulator:
```bash
pnpm build-emulator
```
2. Commit the modified JS file.
---
### 🚀 Production Build
1. Make sure the emulator is built:
```bash
pnpm build-emulator
```
2. Build the frontend:
```bash
pnpm build
```
3. Final output will be in the `dist/` directory.
---
## 💖 Support Sim8085
Sim8085 is a free and open-source project built with care to help students and educators learn 8085 programming with ease. If you find it useful and would like to support its continued development, consider donating:
- 🙌 [GitHub Sponsors](https://github.com/sponsors/debjitbis08)
- ☕ [Buy Me a Coffee](https://buymeacoffee.com/debjit.biswas)
- 💙 [Ko-fi](https://ko-fi.com/debjitbiswas)
Your support helps cover hosting, development time, and the addition of new features. Every little bit counts!
---
© 2013-present [Debjit Biswas](https://www.debjitbiswas.com). BSD-3-Clause License.