Number One

Tom BozicIan NuberGreg RamseyHenry RomeroMatt Unangst

GITHU Processor

General Purpose 32-bit, pipelined computer processor

MIPS-like architecture– Reduced instruction set

24-bit address space– 22 bits, concatenate with ending 00– 32 bit boundaries

16 Registers

Registers

16 Registers (ease in immediate operations) 3 Special Purpose

– R0 – zero– R14 – stack pointer– R15 – return address

Instruction Set Architecture

First two bits indicate instruction category– Load, store, bra/jump, R-type

16 bit immediate built into R-type reduces complexity of design

Addressing Modes– Direct– Indirect with Offset

ISA accounts for full address space– NO PC-relative addressing

Instruction Format

31 30 29 24 23 20 19 16 15 0Op(2) Addr(6) Rt (4) Rs (4) Address Displacement (16)

31 24 23 20 19 16 15 12 11 0Opcode(8) Rd(4) Rs1 (4) Rs2 (4) Immediate (12)

31 30 29 26 25 24 23 20 19 0Op(2) Type(4) Addr (2) Rs (4) Address Continued (20)

Load / Store

R-Type

Bra / Jmp

Instructions

Arithmetic– Add– Addi – add immediate– Sub– Subi – subtract immediate

Data Transfer– Ld - load word– St – store word

Instructions

Logic– And– Andi – And immediate– Or– Ori – Or immediate– Nor– Nand– Sll – logic shift left– Slr – logic shift right

Instructions

Branches– Beq – branch equal to zero– Bne – branch not equal to zero

Jumps– Jmp – jump to specified address– Jsr – jump to subroutine

Interrupt handler Save current PC in register

Nop – No Operation

Datapath Diagram

Functional Units

Register File ALU Control Logic Memory System Assembler

Hardware

Xilinx XCV300/400/600/800 FPGA Keep FPGA on board Make PCB for all off-chip peripherals Connect two boards together via ribbon cable

Processor I/O

Serial RS232 port LCD, Monitor outputs Keypad, Keyboard Inputs

Vital Goals

Implement processor on FPGA in Verilog– Pipelined– Thorough simulation

Complete Assembler Keypad, LCD I/O Make PCB with off-chip peripherals Successfully run assembly program

Extended Goals

On-chip caches (Instruction and data) C Compiler Monitor, Keyboard I/O Multiplier, Divider units Floating Point Units

Individuals Roles

Tom Bozic– Assembler, control logic, documentation

Ian Nuber– Assembler, control logic, test-program design

Greg Ramsey– ALU, PCB design

Henry Romero– PCB design, Memory system

Matt Unangst– Pipeline implementation (forwarding, rollback)– Register File

Schedule

Risks

PCB issues (signal noise, speed, etc)– Wire wrapping

Pipeline complexity– Design allows for insertion of no-ops to essentially

turn machine into multi-cycle machine

Questions?