Assume for a given processor the CPI of arithmetic instructions is 1, the CPI of load/store instructions is 10, and the CPI of branch instructions is 3.

Assume a program has the following instruction breakdowns: 600 million arithmetic instructions, 250 million load/store instructions, 90 million branch instructions.

a) Suppose that new, more powerful arithmetic instructions are

added to the instruction set. On average, through the use of these more powerful

arithmetic instructions, we can reduce the number of arithmetic instructions

needed to execute a program by 25%, and the cost of increasing the clock cycle

time by only 10%. Is this a good design choice? Why?

b) Suppose that we find a way to double the performance of

arithmetic instructions. What is the overall speedup of our machine? What if we

find a way to improve the performance of arithmetic instructions by 10 times?