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Computer Organization (0306-550) - Winter 2009
Homework Assignment #2 - Due January 7
Show all intermediate steps clearly and legibly to obtain full credit.
1. Assume that the code given in question #10 of homework assignment #1 is run
on a CPU with a clock frequency of 2 GHz, that requires the following number of
cycles for each instruction.
Instruction Cycles
add, addi, sll 2
bne 3
lw 5
Ignoring the four instructions before the loops, how many seconds will it take to
execute this code in the worst case?
2. Consider two different CPU implementations of the same instruction set: CPU1
and CPU2. This instruction set has five classes (A, B, C, D, and E) of instructions
whose CPIs for each CPU are given in the table below. CPU1 has a clock rate of
2 GHz, and CPU2 has a clock rate of 2.5 GHz
Class CPI1CPI2
A 1 3
B 3 3
C 4 3
D 5 4
E 7 5
a. What are the peak MIPS ratings of CPU1 and CPU2 ?
b. If the number of instructions executed in a certain program is divided equally
among these instruction classes except for class A, which occurs five times as
often as each of the other classes, which CPU implementation is faster for this
program (i.e., CPU1 or CPU2), and by how much?
