CS401 Quiz 1 Set 3

Q1. Which part of B80500 (encoded instruction) is an opcode?

1. B80
2. B80500
3. 0500
4. B8

Correct answer: B8

Q2. Which of the following is an incorrect XOR operation?

1. XOR AX
2. XOR BX, AX
3. XOR AX, BX
4. XOR BYTE [VAR], 5

Correct answer: XOR AX

Q3. In case of 32-bit processor, the size of an accumulator register will be ___________ bits.

1. 32
2. 16
3. 64
4. 8

Correct answer: 32

Q4. Shift Arithmetic Right (SAR) shifts every bit one place to the right and places a copy of the ______________ significant bit at the ______________ significant place.

1. least, least
2. most, least
3. least, most
4. most, most

Correct answer: most, most

Q5. num1: db 75, 50, 77, 82 Which of the following accesses the third element i.e. 77?

1. num1[2]
2. [num1+4]
3. [num1+2]
4. [num1+3]

Correct answer: [num1+2]

Q6. Constant can never be used as ___________.

1. both source and destination
2. source
3. immediate source
4. destination

Correct answer: destination

Q7. Which of the following is the renamed version of conditional jump JZ?

1. JE
2. JNC
3. JB
4. JA

Correct answer: JE

Q8. The stack pointer marks the ______________ of stack.

1. top
2. top and bottom
3. bottom
4. middle

Correct answer: top

Q9. How jmp is different from jnz?

1. jmp permanently diverts the program flow, but jnz does not
2. jnz permanently diverts the program flow, but jmp does not
3. jmp is an unconditional jump, however jnz is a conditional jump
4. jmp is a conditional jump, however jnz is an unconditional jump

Correct answer: jmp is an unconditional jump, however jnz is a conditional jump

Q10. If AND operation is performed between AX and BX, then how many AND operations will be performed in total?

1. 2
2. 8
3. 32
4. 16

Correct answer: 16