Slide 26
Slide 26 text
Unit cycle architecture: an intrinsically faster approach
• Problem:
• Single/multi-cycle microarchitectures waste time using the
critical path.
• If the longest instruction takes 1100 ps, then every instruction
takes 1100 ps.
• Solution:
• Use a timer to measure the time.
• Set the timer to the duration of the instruction.
• When the timer runs out, move to the next instruction.
Single-Cycle Multi-Cycle Unit-Cycle
Clock Period (ps) 1100 300 100
Cycles Executed 360 1,316 2,748
Execution Time (ps) 396,000 394,800 274,800
Benchmark program: Square root
Unit-Cycle is more than 40% faster than Single-Cycle or Multi-Cycle