Homework 1: COMPUTER ARCHITECTURE (CS_472_X001_F2020)
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Homework 1
Due Oct 14 at 8am Points 20 Questions 16 Available until Dec 20 at 11:59pm
Time Lim
...
Homework 1: COMPUTER ARCHITECTURE (CS_472_X001_F2020)
https://canvas.oregonstate.edu/courses/1781618/quizzes/2593664 1/15
Homework 1
Due Oct 14 at 8am Points 20 Questions 16 Available until Dec 20 at 11:59pm
Time Limit None
Instructions
Attempt History
Attempt Time Score
LATEST Attempt 1 4,682 minutes 8 out of 20
Score for this quiz: 8 out of 20
Submitted Oct 14 at 5:41am
This attempt took 4,682 minutes.
Homework #1 covers the topics taught in Module 1 and Module 2.
It consists of 4 Questions (each of them consists of sub-questions )
There is no time-limit.
Question 1
In this question, we will compare the performance of two processors, pA and pB. The
processors are identical except:
The ALU in pB has specialized multiplier logic and supports the mult instruction
The ALU in pA does not have multiplier logic and does not support the mult
instruction
pB's cycle time is 20% longer than pA's cycle time due to the added complexity
Because pA does not support a mult instruction, multiplication must be done by a
software algorithm that uses other available instructions to calculate the result. (The
assembler for pA provides a mult pseudo-instruction, which is expanded to several
instructions during assembly.)
Assume the following real-world instruction distribution for each processor running the
same workload.
pA pB CPI
MULT 0% 5% 32
LW 5% 25% 3
SW 5% 25% 2
R-TYPE 70% 15% 1
BEQ 20% 30% 212/5/2020 Homework 1: COMPUTER ARCHITECTURE (CS_472_X001_F2020)
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Question 1 0 / 1 pts
Question 1.1
What is the average CPI of pA for this workload?
Exact answer.
Y You Answered ou Answered 3
Correct Answers Correct Answers 1.35 (with margin: 0)
1.35 = 0.05(3) + 0.05(2) + 0.70(1) + 0.20(2)
Question 2 0 / 1 pts
Question 1.2
What is the average CPI of pB for this workload?
Exact answer.
Y You Answered ou Answered 2.5
Correct Answers Correct Answers 3.6 (with margin: 0)
3.6 = 0.05(32) + 0.25(3) + 0.25(2) + 0.15(1) + 0.30(2)
Question 3 0 / 1 pts
Question 1.3
What is the ratio of the total number of executed instructions of pA over that of pB?
(hint: LW and SW instructions remain the same in pB as they are not used for12/5/2020 Homework 1: COMPUTER ARCHITECTURE (CS_472_X001_F2020)
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multiplication)
Exact answer. Enter either the ratio or its reciprocal.
Y You Answered ou Answered 2.72
Correct Answers Correct Answers 5 (with margin: 0)
0.2 (with margin: 0)
pA and pB execute the same number of LW/SW instructions for a given
workload.
If a workload is A instructions on pA and B instructions to execute on pB, then
we can say that 5%*A = 25%*B
A/B = 5
pA executes 5 times as many instructions as pB
Question 4 0 / 1 pts
Question 1.4
pA runs the workload in 150 seconds. How many seconds does pB take to run the
same workload?
Exact answer.
Y You Answered ou Answered 180
Correct Answers Correct Answers 96 (with margin: 0)
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