MIPS Processor Simulator

A Python-based simulator for a MIPS processor that supports various instruction types:

• R-type (add, sub, sll, slt, xor, or, nor, jr, mult, div, mflo)
• I-type (addi, lw, sw, beq, bne)
• J-type (j, jal)

Features

• Simulates 32 general-purpose MIPS registers
• Supports stack operations
• Implements memory hierarchy
• Supports jr $ra for function returns
• Interactive menu interface
• Append and write mode for compiler and interpreter style execution

Usage

Clone the repo to your desired location. Run the simulator from the command line:

git clone https://github.com/moneytosms/MIPS_Processor.git
cd MIPS_Processor
python processor.py

Menu Options

1. Load instructions (as hex words)
2. Execute cycles
3. Show all registers
4. Help - Learn about MIPS
5. Exit

Example: Factorial Calculation

To calculate factorial of 5, enter these instructions:

0x20080005 0x20090001 0x11000004 0x01280018 0x00004812 0x2108FFFF 0x08100002

Overview

This simulator implements a basic MIPS architecture with:

• 32 general-purpose registers
• Memory model with text, data, and stack segments
• Support for core instruction types (R, I, and J)
• Function calls via jal and jr $ra
• Stack operations

Memory Layout

The simulator uses the standard MIPS memory layout:

• 0x00400000: Text segment (Code)
• 0x10000000: Data segment (Global variables)
• 0x7fffffff: Stack segment (grows downward)

Supported Instructions

R-type Instructions

• add - Add two registers
• sub - Subtract two registers
• sll - Shift left logical
• slt - Set less than
• xor - Exclusive OR
• or - Logical OR
• nor - Logical NOR
• and - Logical AND
• jr - Jump register
• mult - Multiply
• div - Divide
• mflo - Move from LO register

I-type Instructions

• addi - Add immediate
• lw - Load word
• sw - Store word
• beq - Branch if equal
• bne - Branch if not equal

J-type Instructions

• j - Jump
• jal - Jump and link (function calls)

Function Calls

The simulator supports nested function calls with stack management. For example:

# Save return address
addi $sp, $sp, -4
sw   $ra, 0($sp)

# Function body...

# Restore return address and return
lw   $ra, 0($sp)
addi $sp, $sp, 4
jr   $ra

Testing

The simulator has been thoroughly tested with:

• Register operations
• Memory operations
• Basic arithmetic and logical operations
• Branch instructions
• Function calls
• Complex programs (e.g., factorial calculation)

Learning Resources

For more information about MIPS architecture and assembly:

1. MIPS Reference Sheet: https://inst.eecs.berkeley.edu/~cs61c/resources/MIPS_Green_Sheet.pdf
2. MIPS Assembly Programming Tutorial: https://chortle.ccsu.edu/AssemblyTutorial/index.html
3. Book: 'See MIPS Run' by Dominic Sweetman
4. Book: 'Computer Organization and Design' by Patterson and Hennessy

Pipeline Visualization

Also contains Pipeline visualization tool in a menu driven format, to run the program, enter the repository directory, run from CLI.

git clone https://github.com/moneytosms/MIPS_Processor.git
cd MIPS_Processor
python pipeline.py