8085 Microprocessor MCQ

71. The following instruction copies a byte of data from the accumulator into the memory address given in the instruction

  1. STA address
  2. LDAX B
  3. LHLD address
  4. LDA address

Answer
Answer. a

72. The instruction that exchanges top of stack with HL pair is

  1. XTHL
  2. SPHL
  3. PUSH H
  4. POP H

Answer
Answer. a

73. In 8085 microprocessor, during PUSH PSW Operation, Stack pointer is

  1. Decremented by one
  2. Decremented by two
  3. Incremented by one
  4. Incremented by two

Answer
Answer. b

74. While a program is being executed in an Intel 8085 microprocessor, the program counter of the microprocessor contains:

  1. The memory address of the instruction that is being currently executed.
  2. The memory address of the instruction that is to be executed next.
  3. The number of instructions that have already been executed.
  4. The total number of instructions in the current program still to be executed.

Answer
Answer. b

75. The description of a program counter (PC) in 8085 microprocessor is

  1. An up/down counter
  2. An 8-bit register
  3. Initialized automatically by microprocessor
  4. Used to point to stack memory area

Answer
Answer. c

76. If the status of the control lines SI and SO is LOW, then 8085 microprocessor is performing

  1. Reset operation
  2. HOLD operation
  3. Halt operation
  4. Interrupt acknowledge

Answer
Answer. c

77.  LXI SP, 7FFF H

MVI A, 25 H

XRI 02 H

PUSH PSW

POP H

MOV A,L

ORI 10 H

HLT

What are the contents of A, H, L, SP and PSW registers after executing the above set of instructions? Assume undefined flags always remain clear.

  1. 10H, 25H, 00H, 7FFFH, 00H respectively
  2. 14H, 27H, 04H, 7FFFH, 04H respectively
  3. 14H, 25H, 00H. 7FFFH, 04H respectively
  4. 10H, 27H, 04H, 7FFFH, 00H respectively

Answer
Answer. b

78. The content of the programme counter of an 8085 microprocessor is

  1. the total number of instructions in the program already executed.
  2. the total number of times a subroutine is called.
  3. the memory address of the instruction that is being currently executed.
  4. the memory address of the instruction that is to be executed next.

Answer
Answer. d

79. The opcode for the instruction “Add Immediately to Accumulator with carry” in 8085 microprocessor is

  1. ADI
  2. ACI
  3. ADC
  4. ADD

Answer
Answer. b

80. MVI A, AA H

ORI FFH

RRC

RRC

CMC

INR A

What are the contents of A and PSW registers after executing the above set of instructions in sequence?

  1. AAH and 00H
  2. FFH and 66H
  3. 00H and 54H
  4. 00H and 00H

Answer
Answer. c

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