Microprocessors Questions and Answers – Instruction Set Features -1

This set of Microprocessor Multiple Choice Questions & Answers (MCQs) focuses on “Instruction Set Features -1”.

1. In which of these modes, the immediate operand is included in the instruction itself?
a) register operand mode
b) immediate operand mode
c) register and immediate operand mode
d) none of the mentioned
View Answer

Answer: b
Explanation: In immediate operand mode, the immediate operand is included in the instruction itself.

2. In register address mode, the operand is stored in
a) 8-bit general purpose register
b) 16-bit general purpose register
c) si or di
d) all of the mentioned
View Answer

Answer: d
Explanation: In register address mode, the operand is stored either in one of the 8-bit or 16-bit general purpose registers or in SI, DI, BX or BP.

3. In which of the following addressing mode, the offset is obtained by adding displacement and contents of one of the base registers?
a) direct mode
b) register mode
c) based mode
d) indexed mode
View Answer

Answer: c
Explanation: In a based mode, the offset is obtained by adding displacement and contents of one of the base registers, either BX or BP.
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4. In which of the following addressing mode, the offset is obtained by adding displacement, with the contents of SI?
a) direct mode
b) register mode
c) based mode
d) indexed mode
View Answer

Answer: d
Explanation: In an indexed mode, the offset is obtained by adding displacement, with contents of an index register, either SI or DI.

5. The address of a location of the operand is calculated by adding the contents of any of the base registers, with the contents of any of index registers in
a) based indexed mode with displacement
b) based indexed mode
c) based mode
d) indexed mode
View Answer

Answer: b
Explanation: In a based indexed mode, the operand is stored at a location, whose address is calculated by adding the contents of any of the base registers, with the contents of any of the index registers.

6. Which of the following is not a data type of 80286?
a) Ordinal or unsigned
b) ASCII
c) Packed BCD
d) None of the mentioned
View Answer

Answer: d
Explanation: The 80286 supports seven data types. They are
1. integer
2. Ordinal (unsigned)
3. pointer
4. string
5. ASCII
6. BCD
7. Packed BCD.

7. The representation of 8-bit or 16-bit signed binary operands using 2’s complement is a data type of
a) Ordinal
b) ASCII
c) Packed BCD
d) integer
View Answer

Answer: d
Explanation: In integer data type, 8-bit or 16-bit signed binary operands are represented using 2’s complement.
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8. The instruction that pushes the general purpose registers, pointer and index registers on to the stack is
a) POPF
b) PUSH Imd
c) PUSH*A
d) PUSHF
View Answer

Answer: c
Explanation: The PUSH*A instruction, pushes the general purpose registers, AX, CX, DX and BX, pointer and index registers, SP, BP, SI, DI, on to the stack.

9. While executing the PUSH*A instruction, the stack pointer is decremented by
a) 1 bit
b) 2 bits
c) 4 bits
d) 16 bits
View Answer

Answer: b
Explanation: The stack pointer is decremented by 16 (eight 2-byte registers).
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10. The statement that is true for the instruction POP*A is
a) flags are unaffected
b) no operands are required
c) exceptions generated are same as that of PUSH*A
d) all of the mentioned
View Answer

Answer: d
Explanation: The POP*A instruction, pops all the contents of the registers DI, SI, BP, SP, BX, DX, CX and AX from the stack in this sequence, that is exactly opposite to that of pushing.

11. The instruction that multiplies the content of AL with a signed immediate operand is
a) MUL
b) SMUL
c) IMUL
d) None of the mentioned
View Answer

Answer: c
Explanation: The IMUL instruction multiplies the content of AL with a signed immediate operand, and the signed 16-bit result is stored in AX.

12. The instruction that represents the ‘rotate source, count’ is
a) RCL
b) RCR
c) ROR
d) All of the mentioned
View Answer

Answer: d
Explanation: The rotate source, count is a group of four instructions containing RCL, RCR, ROL, ROR.

Sanfoundry Global Education & Learning Series – Microprocessors.

Here’s the list of Best Books in Microprocessors.

To practice all areas of Microprocessors, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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