Consider a CPU that has a clock cycle of 10 nanoseconds (ns). It is possible to

Question

Consider a CPU that has a clock cycle of 10 nanoseconds (ns). It is possible to remove some
instructions from its assembly language instruction set to form a second CPU and reduce its
clock cycle to 8 ns. These instructions comprise 4 percent of all code in a typical assembly
language program, and each of these removed instructions would have to be replaced by 3
instructions from the reduced set. Assume that every instruction requires the same number of
clock cycles, c, to complete (i.e., to be fetched, decoded, and executed with results written
back).
(a.) Which CPU has the better performance?
(b.) What percentage of typical code would the removed instructions have to comprise in
order for the two CPUs to have the same performance?
(c.) For what clock cycle for the original CPU would the two CPUs have the same
performance?

Explanation / Answer

1) find time that it takes to do 1e9 opeations For 1st cpu: 10sec For 2nd cpu: 8.64 sec therefore, 2nd is better 2) set up equation 10=(1e9)*(2x+1)*(8e-9) find x 3) set up equation 1e9*x=8.64 find x

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.