Microprocessor Design

This repository contains the Verilog implementation of a simple microprocessor, built and tested using Vivado. The project includes modules for an ALU, register file, and a top-level control unit.

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Features

• 4-Bit Register File:

  • Four general-purpose registers (register1, register2, register3, register4) for storing operands.
  • Read and write operations controlled by read_sel and write_sel signals.
  • Reset functionality to initialize registers to default values.

• Arithmetic Logic Unit (ALU):

  • Performs 12 basic operations, including arithmetic, logic, and bit shifts.
  • Supports addition, subtraction, multiplication, division, AND, OR, XOR, XNOR, and NOT.

• Control Signals:

  • write_enable: Controls write-back to the register file.
  • zero_flag and carry_flag: Indicate zero results and carry conditions.

• Timing Constraints:

  • Proper constraints have been applied to ensure robust synthesis and timing closure.
  • Constraints defined in microprocessor_constraints.xdc file, included in the repository.

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Modules Overview

1. Microprocessor (microprocessor.v)

The top-level module that integrates:

• Register File: For data storage and operand retrieval.
• ALU: For performing arithmetic and logic operations.

2. Register File (register_file.v)

• Contains four 4-bit registers with default values assigned.
• Supports:
  • Read: Two operands can be selected using read_sel1 and read_sel2.
  • Write: Data can be written to a specific register using write_sel.

3. ALU (alu.v)

• Performs arithmetic and logic operations based on a 4-bit opcode (alu_op):

  alu_op	Operation	Description
  0000	Add	operand1 + operand2
  0001	Subtract	operand1 - operand2
  0010	Multiply	operand1 * operand2
  0011	Divide	operand1 / operand2
  0100	AND	operand1 & operand2
  0101	OR	`operand1
  0110	XOR	operand1 ^ operand2
  0111	XNOR	~(operand1 ^ operand2)
  1000	NOT	~operand1
  1001	Right Shift	operand1 >> 1
  1010	Left Shift	operand1 << 1

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Simulation and Verification

Testbench

A testbench (microprocessor_tb.v) is provided to verify functionality. It:

• Stimulates the microprocessor with various inputs.
• Verifies:
  • Correct ALU operations.
  • Proper register read and write-back behavior.
  • Flag conditions (zero and carry).

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Synthesis and STA

• Synthesis:

  • The design was synthesized in Vivado to generate a gate-level netlist.
  • Output netlist file: microprocessor_design.

• Reports:

  • Timing Report: Pre-layout timing results are stored in microprocessor_timing_report.txt.
  • Resource Utilization Report: FPGA resource usage is documented in microprocessor_utilization_report.txt.

• Constraints:

  • Timing and design constraints are defined in microprocessor_constraints.xdc:
    • Clock period.
    • Input/output delays.
    • Reset setup requirements.

• Pre-Layout STA:

  • Timing analysis confirmed no setup or hold violations.
  • Results verified for a clock period of 5.8 ns.

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