FG-8085 Simulator Toolkit

A comprehensive web-based simulator for the Intel 8085 microprocessor, designed for educational purposes and assembly language programming practice.

🌟 Features

• Complete 8085 Instruction Set: Support for all 8085 microprocessor instructions including undocumented ones (all 256 opcodes)
• Comprehensive Machine Code Reference: Searchable and filterable reference table with all 256 opcodes, mnemonics, and descriptions
• Real-time Register & Flag Monitoring: Watch register values and flags change as instructions execute
• Memory Editor: Write and modify machine code directly in memory
• Step-by-Step Execution: Execute instructions one at a time to understand program flow
• Program Loading: Load programs in hexadecimal format
• Interactive Interface: User-friendly design with intuitive controls

🚀 Getting Started

Prerequisites

• Python 3.8 or higher
• Flask web framework
• Modern web browser (Chrome, Firefox, Safari, Edge)

Installation

1. Clone the repository:

   git clone https://github.com/yourusername/8085-simulator.git
   cd 8085-simulator
   

2. Install the required dependencies:

   pip install -r requirements.txt
   

3. Run the application:

   python app.py
   

4. Open your web browser and navigate to:

   http://localhost:5000
   

💻 Usage

Loading a Program

There are two ways to load a program into the simulator:

1. Using the Program Input: Enter hexadecimal bytes separated by spaces in the "Enter Program" field and click "Load Program".
2. Using the Memory Editor: Navigate to the desired memory address, enter the machine code, and click "Execute" to write it to memory.

Executing Instructions

After loading your program, you can execute it in several ways:

• Step: Execute one instruction at a time to observe the changes in registers and flags.
• Run Program: Execute the program continuously until it halts or encounters an error.
• Execute: Execute the instruction at the current memory address.

Monitoring the State

The simulator provides real-time information about:

• Registers: View the contents of all 8085 registers (A, B, C, D, E, H, L, PC, SP).
• Flags: Monitor the status of all flags (S, Z, AC, P, CY).
• Memory: Examine the contents of memory at any address.

Resetting the Simulator

Click the "Reset" button to clear all registers, flags, and memory, returning the simulator to its initial state.

⌨️ Shortcut Keys

Shortcut	Action
Ctrl + R	Reset the simulator
Ctrl + G	Go to specified address
Ctrl + P	Run program
Ctrl + S	Step through instruction
Ctrl + L	Load program
Ctrl + C	Clear instruction history
Ctrl + H	Open help page
Enter	Next memory address
Shift + Enter	Previous address

📚 8085 Instruction Set

The simulator supports the complete 8085 instruction set, including:

• Data Transfer Group: MOV, MVI, LXI, LDA, STA, etc.
• Arithmetic Group: ADD, SUB, INR, DCR, DAD, etc.
• Logical Group: ANA, ORA, XRA, CMP, RLC, RRC, etc.
• Branch Group: JMP, JNZ, JZ, CALL, RET, etc.
• Stack, I/O, and Machine Control Group: PUSH, POP, IN, OUT, EI, DI, etc.

For a complete reference of all 256 instructions (including undocumented ones) with their opcodes, machine codes, and descriptions, visit the Machine Code Reference page.

🧩 Example Programs

Simple Addition Program

3E 05    ; MVI A, 05H  (Load 05H into accumulator)
06 03    ; MVI B, 03H  (Load 03H into register B)
80       ; ADD B       (Add B to A)
76       ; HLT         (Halt)

Memory Transfer Program

21 00 20 ; LXI H, 2000H (Load 2000H into H-L pair)
3E 42    ; MVI A, 42H   (Load 42H into accumulator)
77       ; MOV M, A     (Move A to memory location pointed by H-L)
76       ; HLT          (Halt)

🤝 Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

❤️ Support This Project

If you find this simulator useful for your studies or work, consider supporting the project with a donation:

• Bitcoin: 14GSZ1293s65JjytCjZMz3AFNSUa4ZVN2V
• Monero (XMR): 42GyVekn3tufQjYQS9iN79g9MhzfLDgiu3HVAifDfNuW8MA2bi2UPagXo5ZPzA8rupERybjWsMv5HP7azinFbBxcFf9FW86
• UPI (for users in India): furjack@ybl

Your support helps keep this project maintained and improved. Visit the Donate Page for more information.

📝 License

This project is licensed under the MIT License - see the LICENSE file for details.

🙏 Acknowledgments

• Intel Corporation for the 8085 microprocessor architecture
• The open-source community for various tools and libraries
• All contributors who have helped improve this simulator

📧 Contact

For questions or suggestions, please open an issue in the GitHub repository or contact the me.

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Made with ❤️ for microprocessor enthusiasts and students