A certain microprocessor requires either 2, 3, 4, 8, or 12 machine cycles to perform various operations. Twenty-five percent of its instructions require 2 machine cycles, 20% require 3 machine cycles, 17.5% require 4 machine cycles, 12.5% require 8 machine cycles, and 25% require 12 machine cycles.
a) What is the average number of machine cycles per instruction for this microprocessor?
b) What is the clock rate (machine cycles per second) required for this microprocessor to be a "1 MIPS" processor?
c) Suppose this system requires an extra 20 machine cycles to retrieve an operand from memory. It has to go to memory 40% of the time. What is the average number of machine cycles per instruction for this microprocessor, including its memory fetch instructions?