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CMPE12 S18 Final, Version A
June 11, 2018
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CMPE12 S18 Final, Version A Page 1 of 12 June 11, 2018
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1. (4 points) MIPS32 has how many general purpose registers?
© A. 32
© B. 8
© C. 16
© D. 64
© E. 10
2. (4 points) What is the largest unsigned 6-bit number?
© A. 0x111111
© B. 0x3F
© C. 0xFFF
© D. 0xF
© E. 0x18
3. (4 points) What is the largest signed 2SC 4-bit number (in decimal)?
© A. 8
© B. 4
© C. 6
© D. 16
© E. 7
4. (4 points) Which of these 8-bit signed magnitude numbers is the largest?
© A. 0xEF
© B. 0x7F
© C. 0xFF
© D. 0x8F
© E. 0x80
5. (4 points) True or False: The ASCII character ’A’ is encoded by 10 in decimal.
© A. True
© B. False
6. (4 points) Convert the number 12010 to binary.
© A. 11110002
© B. 11001102
© C. 10110002
© D. 11010012
© E. 10111012
7. (4 points) What is the result in binary of the octal addition 10108 +01008?
© A. 00010001000100002
© B. A42
© C. 11102
© D. 0000000011102
© E. 0010010010002
8. (4 points) Convert 2610 to an excess-8 decimal number.
© A. −2610,excess8
© B. 2610,excess8
© C. −810,excess8
© D. 3410,excess8
© E. 1810,excess8
CMPE12 S18 Final, Version A Page 2 of 12 June 11, 2018
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9. (4 points) A MUX with 4 selector pins has how many inputs?
© A. 16
© B. 8
© C. 7
© D. 12
© E. 4
10. (4 points) If a computer has eight-byte addressability and needs three bits to access a location in memory,
what is the total size of memory in bytes?
© A. 768
© B. 32
© C. 256
© D. 128
© E. 64
11. (4 points) What is this logic circuit?
© A. 2-1 multiplexor
© B. half adder
© C. full adder
© D. shift register
© E. decoder
12. (4 points) What is the unsimplified Product of Sums boolean expression that represents the following truth
table?
A B C Out
0 0 0 1
0 0 1 0
0 1 0 0
0 1 1 1
1 0 0 0
1 0 1 1
1 1 0 1
1 1 1 1
© A. (A¯+ B¯+C) · (A¯+B+C¯) · (A+ B¯+C¯)
© B. (A+B+C) · (A+ B¯+C¯) · (A¯+B+C¯) · (A¯+ B¯+C) · (A¯+ B¯+C¯)
© C. (A+B+C¯) · (A+ B¯+C) · (A¯+B+C)
© D. (A¯+ B¯+C¯) · (A¯+B+C) · (A+ B¯+C) · (A+B+C¯) · (A+B+C)
CMPE12 S18 Final, Version A Page 3 of 12 June 11, 2018
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13. (4 points) What is the result of the following binary XOR operation?
0b 0 0 1 1 1 0 1 1
⊕ 0b 1 0 1 1 1 0 1 0
© A. 100000012
© B. 001110102
© C. 010001002
© D. 011111102
© E. 101110112
14. (4 points) X AND X is:
© A. Always True
© B. Always False
© C. Depends on the value of X
15. (4 points) X OR X is:
© A. Always True
© B. Always False
© C. Depends on the value of X
16. (4 points) What is the result of the following binary AND operation?
0b 0 0 1 1 1 0 1 1
· 0b 1 0 1 1 1 0 1 0
© A. 010001002
© B. 011111102
© C. 100000012
© D. 101110112
© E. 001110102
17. (2 points) How many more transistors does an AND gate have compared to a NAND gate?
© A. 0
© B. 1
© C. 2
© D. 3
© E. 4
18. (2 points) What is the minimum number of transistors needed to create an OR gate?
© A. 2
© B. 3
© C. 4
© D. 5
© E. 6
19. (2 points) Convert the 2SC number 110110112 into a decimal value in base 10.
© A. −4110
© B. 3610
© C. −3710
© D. −9110
© E. −3810
CMPE12 S18 Final, Version A Page 4 of 12 June 11, 2018
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20. (4 points) Convert 0xCAFE to binary.
© A. 01000101010000102
© B. 10101011101111102
© C. 11001010111111112
© D. 11001010111111102
© E. 10101011111010112
21. (4 points) Convert the BCD number 0b0100011100100011 to decimal.
© A. 4723
© B. 043443
© C. 18211
© D. 118
22. (4 points) Convert the 4-bit unsigned binary number 0b1011 to 8 bits.
© A. 0b11110111
© B. 0b11111011
© C. 0b00001011
© D. 0b01111011
© E. 0b11101011
23. (4 points) Consider a 4 bit ripple carry adder with inputs A=0101 and B=0011. What are the results of full
adder for bit 0?
© A. Cout=0, Sum=1
© B. Cout=1, Sum=1
© C. Cout=0, Sum=0
© D. Cout=1, Sum=0
24. (4 points) Assume all signed numbers are two’s complement. Which addition(s) have overflow?
© A. (signed) 0xD02A + 0x57D9 = 0x2803
© B. (unsigned) 0xD02A + 0x57D9 = 0x2803
© C. (unsigned) 0x76F9 + 0x801A = 0xF713
© D. (unsigned) 0x0308 + 0x1198 = 0x14A0
© E. (signed) 0x0308 + 0x1198 = 0x14A0
25. (4 points) The product of two 32-bit numbers has how many bits?
© A. 64 bits
© B. 32 bits
© C. 16 bits
26. (4 points) What is the result when adding the following 6-bit signed magnitude binary numbers?
0b 1 0 0 1 0 0
+ 0b 1 0 1 1 0 0
© A. 0b100000
© B. 0b010000
© C. 0b1100000
© D. 0b000001
© E. 0b110000
CMPE12 S18 Final, Version A Page 5 of 12 June 11, 2018
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27. (4 points) What is the result of the following unsigned 8-bit binary multiplication?
0b 0 0 0 0 0 1 1 0
x 0b 0 0 0 0 1 0 1 0
© A. 0b00111100
© B. 0b00111101
© C. 0b01000001
© D. 0b00010000
© E. 0b01000000
28. (4 points) Assume an arbitrary 16-bit instruction format as follows:
immediate rs1 rs2 opcode
How many instructions can be encoded if there are 4 general purpose registers and an immediate field of 9
bits?
© A. Unknown. There is not enough information given.
© B. 16
© C. 8
© D. 32
© E. 32
29. (4 points) True or False: The address 0x00002028 is word aligned.
© A. True
© B. False
30. (4 points) Which of the following are true about instructions in a MIPS program once assembled?
© A. instructions are stored in the heap
© B. each instruction takes up 8 bytes of memory
© C. instructions range in size from 1 to 4 bytes
© D. instructions are stored in the stack
© E. instructions are stored such that they fall on a word boundary
For the following two questions, assume a portion of data memory looks like this:
ADDRESS CONTENTS
0x10011014 0x90
0x10011013 0x78
0x10011012 0x56
0x10011011 0x34
0x10011010 0x12
31. (4 points) Assuming little endian memory storage, what is in $t0 after the following instructions?
LI $t1, 0x10011011
LW $t0, ($t1)
© A. 0x34567890
© B. 0x90785634
© C. Undefined. There will be an alignment error.
© D. 0x87654321
© E. 0x78563412
CMPE12 S18 Final, Version A Page 6 of 12 June 11, 2018
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32. (4 points) Assuming little endian memory storage, what is in $t7 after the following instructions?
ADDI $t0, $zero, 0x10011010
LH $t7, 2($t0)
SW $t7, ($t0)
LW $t7, ($t0)
© A. 0x00008765
© B. Undefined. There will be an alignment error.
© C. 0x78560000
© D. 0xFFFF8765
© E. 0x00007856
33. (4 points) True or False: A logical left shift and an arithmetic left shift perform the same operation
© A. True
© B. False
34. (4 points) Ignoring branch delay slots, which label will the following code branch/jump to?
LI $t3,92
SRL $t3, $t3, 4
BLE $t3, 4, label1
BGE $t3, 12, label2
BEQ $t3, 5, label3
BLE $t3, 12, label4
J label5
© A. label3
© B. label2
© C. label4
© D. label5
© E. label1
35. (4 points) What value (in decimal) will be in $t2 after the following instructions execute?
LI $t1, 6
SLL $t2, $t1, 4
© A. 6
© B. 24
© C. 194
© D. 96
© E. 48
CMPE12 S18 Final, Version A Page 7 of 12 June 11, 2018
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36. (4 points) What is printed to the screen after the following instructions execute?
.data
prompt1: .ascii "Hello"
prompt2: .asciiz " World!"
prompt3: .asciiz " CMPE 12 Final."
.text
LI $v0, 4
LA $a0, prompt1
SYSCALL
© A. Hello
World!
© B. Hello
© C. Hello World!
© D. Hello World! CMPE 12 Final.
© E. nothing
37. (4 points) What is printed to the screen after the following instructions execute?
.data
P1: .word 0xB
P2: .asciiz "DYoonu’’tr eWOokraryy"
.text
L1: LA $t1, P2
ADDI $t2, $zero, 2
LB $t3, P1
L2: LB $a0, ($t1)
LI $v0, 11
SYSCALL
ADDI $t3, $t3, -1
BEQZ $t3, GLUE
ADD $t1, $t1, $t2
B L2
GLUE: LI $v0, 10
SYSCALL
© A. nothing there is an error
© B. Don’t Worry
© C. B
© D. Don’t Worry You’re Okay
© E. You’re Okay
38. (4 points) True or False: The mantissa in IEEE 754 floating point numbers is stored as two’s comple-
ment.
© A. True
© B. False
CMPE12 S18 Final, Version A Page 8 of 12 June 11, 2018
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39. (4 points) True or False: The exponent in IEEE 754 floating point numbers is stored as two’s comple-
ment.
© A. True
© B. False
40. (4 points) The mantissa in an IEEE 754 Single Precision floating point number is
© A. 16 bits
© B. 8 bits
© C. 46 bits
© D. 11 bits
© E. 23 bits
41. (4 points) Which IEEE 754 Single Precision number is the largest?
© A. 0x389E5D4B
© B. 0x781CCCCC
© C. 0xC1200000
© D. 0x1F9FD394
© E. 0x402CCCCD
42. (4 points) What special exponent is used for NaN, +Inf, and -Inf in IEEE 754 Single Precision floating
point?
© A. 127
© B. 128
© C. 254
© D. 255
43. (4 points) Convert the following decimal value 86.210 to unsigned fractional binary.
© A. 1010110.01
© B. 1010110.0011
© C. 1010110.0011
© D. 1010110.10
© E. 1010110.01
44. (4 points) The single precision floating point number 0x41680000 is what value in decimal?
© A. 3.625
© B. 14.5
© C. 8.25
© D. 20
© E. 41.68
45. (4 points) Convert 47.62510 to single precision floating point format in hex
© A. 0x423F7000
© B. 0x423E8000
© C. 0x425F4000
© D. 0x42F7D000
© E. 0x42DF4000
46. (4 points) Compute the single precision floating point value of 0.2510 +10010
© A. 0x40D20000
© B. 0x42E48000
© C. 0x42C88000
© D. 0x40A40000
© E. 0x42C90000
CMPE12 S18 Final, Version A Page 9 of 12 June 11, 2018
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47. (4 points) By what value is PC(program counter) incremented each time a non-branch or jump instruction
is executed?
© A. 4
© B. 1
© C. -1
© D. 2
48. (4 points) Processing an instruction requires the following steps:
a. Fetch instruction from memory
b. Write back result
c. Memory Read/Write
d. Decode instruction and access operands
e. Execute operation
What is the correct ordering for the steps?
© A. adecb
© B. acdeb
© C. abcde
© D. adebc
© E. bdeca
49. (4 points) Assume the following sequence of push and pop operations on a stack. What is the order of items
being popped off the stack?
PUSH A
PUSH B
POP
PUSH C
PUSH D
POP
PUSH E
POP
POP
POP
© A. EDCBA
© B. BADCE
© C. BDECA
© D. ABCDE
© E. ACEDB
50. (4 points) The stack is used for all of the following except:
© A. Passing more than 4 arguments
© B. Preserving register values
© C. Returning more than 2 values
© D. Storing temporary local data
© E. Dynamically allocating global data
CMPE12 S18 Final, Version A Page 10 of 12 June 11, 2018
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51. (4 points) Which register(s) in MIPS must the callee preserve?
© A. $k0-$k1
© B. $t0-$t9
© C. $v0-$v1
© D. $s0-$s7
© E. $a0-$a3
52. (4 points) Values returned from a subroutine are passed in which registers?
© A. $k0-$k1
© B. $t0-$t9
© C. $a0-$a3
© D. $v0-$v1
© E. $s0-$s7
53. (4 points) True or False: The $fp register automatically points to the last value of the $sp after a function
call.
© A. True
© B. False
54. (4 points) Which combination of MIPS instructions perform a push operation of one element onto the
stack?
© A. LW $t0, ($sp)
ADDI $sp, $sp, 4
© B. ADDI $sp, $sp, 4
LW $t0, ($sp)
© C. SW $t0, ($sp)
SUBI $sp, $sp, 4
© D. SUBI $sp, $sp, 4
SW $t0, ($sp)
55. (4 points) When does the value in $ra need to be saved by the user?
© A. anytime a function is called
© B. any time a branch is executed
© C. never
© D. when there are nested functions
© E. in every program
This table shows the state of the $t0-$t4 registers before and after four successive instructions. The next four
problems ask to fill in the omission (indicated by the number <#>) in the instructions and register file.
Instr 1: SRA $t0, $t0, <1>
Instr 2: <2> $t1, ($t2)
Instr 3: LW <3>, ($t2)
Instr 4: ADDI $t3, $t3, -8
Reg Initial After Instr 1 After Instr 2 After Instr 3 After Instr 4
$t0 0xABCDEF00 0xF579BDE0 0xF579BDE0 0xF579BDE0 0xF579BDE0
$t1 0x000A5C11 0x000A5C11 0x000A5C11 0x000A5C11 0x000A5C11
$t2 0x1001100C 0x1001100C 0x1001100C 0x1001100C 0x1001100C
$t3 0xFFFFFFAA 0xFFFFFFAA 0xFFFFFFAA 0xFFFFFFAA < 4 >
$t4 0xFFFA5C11 0xFFFA5C11 0xFFFA5C11 0x00005C11 0x00005C11
CMPE12 S18 Final, Version A Page 11 of 12 June 11, 2018
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56. (4 points) What is <1>?
© A. $t1
© B. $t0
© C. There is not enough information to answer this.
© D. 1
© E. 3
57. (4 points) What is <2>?
© A. SH
© B. SB
© C. LW
© D. There is not enough information to answer this.
© E. LB
58. (4 points) What is <3>?
© A. 0x000A5C11
© B. $t1
© C. $t4
© D. There is not enough information to answer this.
© E. 0xFFFF
59. (4 points) What is <4>?
© A. 0x00000064
© B. 0xFFFFFFA2
© C. 0x00000048
© D. There is not enough information to answer this.
© E. 0xFFFFFFB2
60. (4 points) True or False: An object file contains only machine langauge instructions.
© A. True
© B. False
61. (4 points) True or False: ISR stands for Interrupt Service Routine.
© A. True
© B. False
62. (4 points) Which instruction cannot cause an exception?
© A. SW
© B. LW
© C. SLL
© D. SYSCALL
© E. ADD
CMPE12 S18 Final, Version A Page 12 of 12 June 11, 2018