Computer Architecture and Systems Software

Question 1
The following tasks consider designing and writing computer programs using assembly
language. For each task, the program should produce valid results after loading and
executing in the pcspim or xspim simulator. You should ensure that your programs are
ecient and well commented.
A.Design and write an MIPS assembly program that accepts three input numbers and
outputs the following numbers in sequence.
The largest of 3 inputs, the median of 3 inputs, the smallest of 3 inputs,
the dierence between the largest and smallest”
You should attach the design of your program (in terms of a
ow-chart diagram)
and your MIPS codes in the submission le. [13 marks]
B.For the program in Part A., explain and demonstrate its execution in the laboratory
sessions in Weeks 8, 9 or 10, and answer relevant questions.
[17 marks]
C.GivenNas a user-entered positive number (i.e.,N >0), design and write one of
the following MIPS assembly programs that depend on the last digit of your UoB
number.
Last digit of Program specications
your UoB number
Odd Add all odd numbers between 0 andN(inclusive)
and display the result
Even Add all even numbers between 0 andN(inclusive)
and display the result
Your program shall prompt the user to enter an input numberN. If the user enters
a zero or negative number, then your program shall stop immediately.
You should attach the design of your program (in terms of a
ow-chart diagram)
and your MIPS codes in the submission le.
[13 marks]
D.For the program in Part C., explain and demonstrate its execution in the laboratory
sessions in Weeks 8, 9 or 10, and answer relevant questions.
[17 marks]

Computer Architecture and Systems Software
Instructions:
• This coursework consists of analysis, design and demonstration tasks for simulating
logic circuits for a fire detector. All tasks are compulsory.
• Total marks from all tasks are 100 marks. Marks for each sub-task are indicated in
the corresponding sub-task. Marking criteria are indicated in Appendix on page 5.
• This coursework is worth 20% of the year’s assessment.
• It is a requirement to submit your coursework (analysis and design tasks) as electronic
submission via Blackboard. The submitted document has to be typed and
only word and pdf file is accepted. Please name your file as:
CASS CW2 YourUBnumber (with appropriate .doc, .docx or .pdf extensions)
where YourUBnumber has to be replaced by your own UB number.
• In addition to electronic submission, you should also demonstrate working systems
for the specified tasks to a lab demonstrator during your laboratory sessions. It is
compulsory that each demonstration has to be accompanied by electronic submission
for marks to be given.
• Submission deadline: The assignment along with the design work must be submitted
to the BlackBoard (under Assessment) by Monday, 04th April 2016, 4 pm. Do
not forget to press the SUBMIT button.
• Late submission without approved extenuating circumstances will receive zero mark.
• It is your responsibility to ensure that the submitted file is viewable and readable.
Marking will be based on the contents of submitted file.
• Feedback report on your coursework will be available on BlackBoard at the end of
the exam period.
CM-0107L page 1 of 5
Scenario:
You are asked by a non-governmental organization FGH to design and implement a fire
detection system in its new built office in Bradford. The organization requires 4 sensors to
be installed in order to automatically detect fire events. The 4 sensors (Inputs) include
2 high-temperature sensors, a flame detector and a smoke detector. A fire-alarm signal
(Outputs) denoted by ALARM is triggered only when appropriate sensors are activated
according to the specification given by the digits of your UB number as described in the
header Operation below.
You remember from your CASS class that the above system can be designed and
implemented using a logic circuit with the following parameters.
Inputs (from 4 sensors):
– W: 1st high-temperature sensor reading (0 = low temperature, 1 = high temperature)
– X: 2nd high-temperature sensor reading (0 = low temperature, 1 = high
temperature)
– Y : flame detector reading (0 = no flame, 1 = flame detected)
– Z: smoke detector (0 = no smoke, 1 = smoke detected)
Output:
– ALARM: fire-alarm signal (0 = alarm off, 1 = alarm on)
Operation:
Assume that your 8-digit UB number is in decimal and the 8 digits are denoted
by
d0d1d2d3d4d5d6d7
The 4-bit binary representations of the decimal numbers d7, d5 and d3 determine
the output ALARM for some input combinations. See the example below
for the detailed instructions.
Example:
In this example, a UB number 14027212 will be used. The blue color in the subsequent
descriptions will be used to indicate steps for the UB number 14027212. For the tasks, you
should clearly describe the steps for your own UB number and update those written
in blue using your own UB number.
• For the UB number 14027212, then d7 = 2, d5 = 2 and d3 = 2.
CM-0107L page 2 of 5
• 4-bit binary representations of d7 = 2, d5 = 2 and d3 = 2 are:
d7= 2 ⇒ 0010
d5= 2 ⇒ 0010
d3= 2 ⇒ 0010
• The output ALARM then follows the following truth table.
W X Y Z ALARM Remarks
0 0 0 0 0 Always 0
0 0 0 1 0 First bit of d7 (MSB)
0 0 1 0 0 Second bit of d7
0 0 1 1 1 Third bit of d7
0 1 0 0 X Don’t care
0 1 0 1 0 Fourth bit of d7 (LSB)
0 1 1 0 0 First bit of d5 (MSB)
0 1 1 1 0 Second bit of d5
1 0 0 0 X Don’t care
1 0 0 1 1 Third bit of d5
1 0 1 0 0 Fourth bit of d5 (LSB)
1 0 1 1 0 First bit of d3 (MSB)
1 1 0 0 0 Second bit of d3
1 1 0 1 1 Third bit of d3
1 1 1 0 0 Fourth bit of d3 (LSB)
1 1 1 1 1 Always 1
Tasks:
A. Using your own UB number, evaluate the truth table for the fire-alarm system
and derive a standard Boolean expression for the output ALARM in the sum-ofproducts
form.
[15 marks]
B. For the sum-of-products in Part A.:
B1. Draw a Karnaugh-map (K-map) corresponding to the output ALARM in terms
of inputs W, X, Y and Z. [12 marks]
B2. Using the K-map in Part B1., simplify the sum-of-products expression.
[13 marks]
C. For the simplified expression obtained in B2.:
CM-0107L page 3 of 5
C1. Design a multiple-input NOT, AND and OR logic gate implementation of the
circuit. Explain your design steps and attach the design diagram to your
submission file. [10 marks]
C2. Demonstrate your logic gate implementation in the laboratory sessions and
answer relevant questions. [20 marks]
D. For the simplified expression obtained in B2.:
D1. Design a multiple-input NAND logic gate implementation of the circuit. Explain
your design steps and attach the design diagram to your submission file.
(Remark: use only NAND gates.) [10 marks]
D2. Demonstrate your logic gate implementation in the laboratory sessions and
answer relevant questions. [20 marks]
CM-0107L page 4 of 5
Appendix
Marking schemes and criteria in terms of percentage of the marks:
0-20 % Basic and confused understanding with erroneous calculations and programming.
20-40 % Basic understanding with some correct and some erroneous steps and calculations.
40-60 % Good understanding with mostly correct steps and calculations but with
minor mistakes or missing points.
60-80 % Good demonstration of understanding with correct steps and calculations
but non-significant errors.
80-100 % Outstanding demonstration of understanding with correct steps and calculations
and good presentation.
CM-0107L page 5 of 5