CSCE 430: Computer Architecture Final Project Group E: Matt Horn Dongpu Jin Nick Briganti Sean Hicks Overview 3 stage pipeline LCD panel output Static branch not taken predictor Write through Instruction and Data Caches Versatile assembler for rapid development Pipeline Three stages pipeline IF/ID EX MEM/WB Two pipeline registers ID/EX register EX/MEM register Pipeline Save both signal and data for next stage Synchronous Clock in values on the rising edge Clock cannot be too fast, because of tsu and th Forwarding Unit Data hazards happens because of data dependency lw r1 0 addi r2 r1 2 Need to forward value for lw directly to ALU source Forwarding Unit IF (WRITE) and (rt = Dest) then ForwardA = 1 IF (WRITE) and (rd= Dest) then ForwardB = 1 Hazard Detection Handles cases where Forwarding Unit is not enough -- Ex:lw $s0 0($0) add $s2 $s0 $s1 Inserts Noops by deasserting control signals and stalls PC in order to halt pipeline Branch Predictor Static Branch not Taken predictor Deasserts control signals for pipeline when a branch is taken Otherwise, instructions continue to execute Penalty for correct branch = 0 cycles Penalty for an incorrect branch = 2 cycles Instruction Cache 16 sets, 4 words/block Direct mapped Address Breakdown 4 bit tag 4 bit index 2 bit offset 8 cycle penalty Instruction Cache Data Cache Same specs as instruction cache except 2 bit tag Write-through policy 8 cycle delay for read miss 9 cycle delay for write miss Data Cache Overall Verification LCD Panel Includes 128 words which mirror data memory Handles most user IO for the board User selects location with switches LCD Panel displays MEM[0-127] LCD Panel Advantages of LCD memory mirroring data Simplifies program development Aids debugging on the board Disadvantages Less versatile, displayed data must appear in memory locations 0-127 Assembler Final instruction set Instruction TypeSyntaxOpcodeFunction AddRAdd $rd $rs $rt032 SubRSub $rd $rs $rt034 AndRAnd $rd $rs $rt036 OrROr $rd $rs $rt037 Add ImmediateIAddi $rs $rt imm8-- Load WordILw $rt imm $rs35-- Store WordISw $rt imm $rs43-- Branch if EqualIBeq $rs $rt imm4-- Branch if Not EqualIBne $rs $rt imm5-- JumpJJ label2-- Jump and LinkJjal label3-- Assembler Data driven, ISA parsed before assembly Instruction set Tokens Registers Assembler - Instructions add rd,rs,rt;op=0, rs, rt, rd, shamt=0, funct=32 addi rs, rt, imm;op=8, rt, rs, imm lui rs, imm;op=15, rs, rt=0, imm bne rs, rt, imm;op=5, rs, rt, ~imm jal label;op=3, label jr rs;op=0, rs, rt=0, rd=0, shamt=0, funct=8 Assembler - Tokens rd 5 rs 5 rt 5 op 6 imm +16 label +26 shamt 5 funct 6 Assembler - Registers zero at 1 v0 2 v1 3 a0 4 a1 5 a2 6 a3 7 t0 8 Assembler - Output # Reads memory location 0, then sorts that many numbers in the following memory values 1-n main: lw $s1 0 $0# load memory location 0 into $s1 addi $s1 $s1 1# increment $s1 for comparison with our "for" loop outer: addi $s0 $0 0# s0 is != 0 if a value has been changed during a bubble sort sweep addi $s2 $0 1# s2 holds the current outer iteration of bubble sort BEGIN 0: 8C110000; -- lw : ; -- addi : ; -- addi : ; -- addi : ; -- addi : 8E48FFFF; -- lw : 8E490000; -- lw : ; -- sub : 3D608000; -- lui : 016A6024; -- and Questions?