A high-performance, 32-bit MIPS processor implementation featuring a five-stage pipeline architecture with comprehensive instruction support for arithmetic, logical, and memory operations.
This project presents a complete MIPS32 processor design implemented in Verilog HDL, featuring a classical five-stage pipeline (IF-ID-EX-MEM-WB) with master-slave register control. The processor supports 11 carefully selected MIPS instructions, demonstrating fundamental concepts of modern processor architecture including pipelining, hazard management, and memory hierarchy.
- Five-Stage Pipeline Architecture with optimized data flow
- Dual-Port Register File supporting simultaneous read operations
- Synchronous Memory Subsystem with separate instruction and data memories
- Advanced ALU Design supporting arithmetic, logical, and comparison operations
- Master-Slave Pipeline Control ensuring proper timing and data integrity
- Comprehensive Instruction Support covering essential MIPS operations
The processor implements a classical RISC pipeline with the following stages:
| Stage | Function | Components |
|---|---|---|
| IF | Instruction Fetch | Program Counter, Instruction Memory, IF/ID Register |
| ID | Instruction Decode | Register File, Control Logic, Sign Extension, ID/EX Register |
| EX | Execute | Arithmetic Logic Unit, EX/MEM Register |
| MEM | Memory Access | Data Memory Interface, Load/Store Logic, MEM/WB Register |
| WB | Write Back | Register File Write Control, Destination Selection |
Program Counter (PC)
- 10-bit counter supporting 1024 instruction addresses
- Automatic increment with each clock cycle
- Reset capability for program initialization
Register File
- 32 general-purpose registers (32-bit width)
- Dual read ports for simultaneous operand access
- Single write port with enable control
- Register $0 hardwired to zero (MIPS standard)
Arithmetic Logic Unit (ALU)
- 32-bit operand processing
- Opcode-based operation selection
- Support for arithmetic, logical, and comparison operations
- Synchronous operation with clock edge alignment
Memory Subsystem
- Instruction Memory: 1K × 32-bit preloaded program storage
- Data Memory: 1K × 32-bit synchronous read/write memory
- Word-aligned addressing with automatic address translation
The processor implements a carefully curated subset of the MIPS32 instruction set:
ADD rd, rs, rt # rd = rs + rt
SUB rd, rs, rt # rd = rs - rt
MUL rd, rs, rt # rd = rs × rt
ADDI rt, rs, imm # rt = rs + sign_extend(imm)AND rd, rs, rt # rd = rs & rt
OR rd, rs, rt # rd = rs | rt
SLT rd, rs, rt # rd = (rs < rt) ? 1 : 0SLLI rd, rt, shamt # rd = rt << shamtLW rt, offset(rs) # rt = Memory[rs + sign_extend(offset)]
SW rt, offset(rs) # Memory[rs + sign_extend(offset)] = rtThe processor supports standard MIPS instruction formats:
R-Type Format (Arithmetic/Logical)
[31-26] [25-21] [20-16] [15-11] [10-6] [5-0]
opcode rs rt rd shamt funct
I-Type Format (Immediate/Memory)
[31-26] [25-21] [20-16] [15-0]
opcode rs rt immediate
The processor utilizes variable-width pipeline buses optimized for each stage:
IF/ID Pipeline Register (42 bits)
- Instruction word (32 bits)
- Program counter value (10 bits)
ID/EX Pipeline Register (108 bits)
- Instruction opcode (6 bits)
- Source operands A and B (64 bits)
- Destination register address (5 bits)
- Control signals and padding (33 bits)
EX/MEM Pipeline Register (76 bits)
- Store data for memory operations (32 bits)
- Instruction opcode (6 bits)
- ALU result/memory address (32 bits)
- Destination register and control (6 bits)
MEM/WB Pipeline Register (44 bits)
- Instruction opcode (6 bits)
- Write-back data (32 bits)
- Destination register address (5 bits)
- Load operation flag (1 bit)
The processor employs master-slave flip-flops for pipeline register implementation:
- Rising Edge: Data latches into master stage
- Falling Edge: Data propagates to slave stage and pipeline outputs
- Synchronous Operation: All pipeline stages advance simultaneously
- Reset Capability: Global reset clears all pipeline stages
| Parameter | Specification |
|---|---|
| Architecture | MIPS32 with 5-stage pipeline |
| Data Width | 32-bit throughout |
| Instruction Width | 32-bit fixed format |
| Register File | 32 × 32-bit registers |
| Program Counter | 10-bit (1024 instruction capacity) |
| Instruction Memory | 1K × 32-bit, preloaded |
| Data Memory | 1K × 32-bit, synchronous |
| ALU Operations | 9 primary operations |
| Pipeline Registers | Master-slave with dual-edge clocking |
- Throughput: One instruction per clock cycle (steady state)
- Latency: 5 clock cycles per instruction (pipeline depth)
- Hazard Handling: Currently implements structural hazard avoidance
- Logic Elements: Optimized for FPGA implementation
- Memory Usage: Efficient dual-memory architecture
- Critical Path: ALU operations determine maximum frequency
- Control Flow: No branch or jump instruction support
- Hazard Detection: Limited data hazard resolution
- Memory Model: Word-aligned access only
- Exception Handling: No interrupt or exception support
- Simplified ISA: Focus on core MIPS operations for educational clarity
- Synchronous Design: All operations tied to single clock domain
- Harvard Architecture: Separate instruction and data memories
- Implement branch instructions (BEQ, BNE, BLT)
- Add jump instructions (J, JAL, JR)
- Integrate branch prediction logic
- Data forwarding network implementation
- Pipeline stall and flush mechanisms
- Load-use hazard detection
- Instruction cache integration
- Data cache implementation
- Pipeline depth optimization analysis
- Floating-point unit integration
- Coprocessor interface development
- Exception and interrupt handling
- HDL Simulator: ModelSim, Vivado, or Icarus Verilog
- Synthesis Tools: Xilinx Vivado or Intel Quartus (for FPGA implementation)
- Assembly Tools: MIPS cross-assembler for program development
- Clone repository and navigate to project directory
- Compile all Verilog source files in dependency order
- Load testbench and execute simulation
- Analyze waveforms and verify correct operation