T.H.A.D.D. GROUP TOM DUAN HELEN YU ANDY LEE DANNY HUANG DAWEY HUANG DSP Enabled Processor Design T.H.A.D.D. GROUP TOM DUAN HELEN YU ANDY LEE DANNY HUANG DAWEY HUANG
Agenda Datapath Design Memory Subsystem Power Optimization Performance
5-Stage Pipeline IF/ID PIPELINE REG ID/EX PIPELINE REG EX/MEM PIPELINE REG MEM/WB PIPELINE REG INSTRUCTION CACHE REGISTER FILE DATA CACHE MAC STAGE 1 MAC STAGE 2 BRANCH LOGIC ALU JUMP LOGIC
Multiply and Accumulate 2-stage pipeline multiplier No stalling when LW followed by MAC ID/EX PIPELINE REG EX/MEM PIPELINE REG MEM/WB PIPELINE REG REGISTER FILE MULTIPIER 1 MULTIPIER 2
Critical Path (WB stage) MEM/WB PIPELINE REG 16 MAC STAGE 2 FROM DATA MEMORY 16 32 32 MUX 32 32 32 TO REGISTER FILE
Memory Subsystem 2x clock rate of processor 3 controllers sdram instruction block data block asynchronous component interface (arbitrator)
Clock Divider CLK ICLK Counter CLK2X
Memory Subsystem Diagram INSTRUCTION CACHE BLOCK DATA CACHE BLOCK BUFFER CACHE CONTROL CONTROL MAIN CACHE VICTIM CACHE miss data miss data address address ARBITRATOR ready ready address SDRAM BLOCK SDRAM (GIVEN) CONTROLLER ready
Cache Organization
Instruction Cache/Controller ADDRESS Cache Blocks Controller FSM 5 BLOCKS EACH 4 WORDS DATA ADDRESS HIT CLK IDLE WORD READ WRITE DISABLE CHECK SDRAM READY MISS SDRAM DATA MISS SDRAM ADDRESS DOUT
Data Cache
Data Cache <-> Victim Cache
Power Reduction Methods Limiting VHDL sensitivity list Balance input arrival Enable/Disable components Eliminate unnecessary control signals & data buses Minimize execution time to lower supply voltage
Power Consumption of Components Supply voltage = 2.5Volts
Component Optimization Results (1) Supply voltage = 2.5Volts
Component Optimization Results (2) Supply voltage = 2.5Volts
Supply Voltage Reduction Results
Supply Voltage Comparison
Design Challenges what we learned: power optimization concepts what surprised us: component interface timing what challenged us: reducing cache miss
Conclusion A Very Rewarding Project Excellent Performance Can Sleep Again!