8086/8088 Instruction Set MCQs : This section focuses on the "8086/8088 Instruction Set". These Multiple Choice Questions (MCQs) should be practiced to improve the 8086/8088 Instruction Set skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.
Question 1
In general, the destination operand of an instruction can be
A. memory location
B. register
C. immediate data
D. memory location and register
Question 2
In general, the source operand of an instruction can be
A. memory location
B. register
C. immediate data
D. all of the mentioned
Question 3
In POP instruction, after each execution of the instruction, the stack pointer is
A. incremented by 1
B. decremented by 1
C. incremented by 2
D. decremented by 2
Question 4
In PUSH instruction, after each execution of the instruction, the stack pointer is
A. incremented by 1
B. decremented by 1
C. incremented by 2
D. decremented by 2
Question 5
During comparison operation, the result of comparing or subtraction is stored in
A. memory
B. registers
C. stack
D. no where
Question 6
NOP instruction introduces
A. Address
B. Delay
C. Memory location
D. None of the mentioned
Question 7
The Carry flag is undefined after performing the operation
A. AAA
B. ADC
C. AAM
D. AAD
Question 8
The expansion of DAA is
A. decimal adjust after addition
B. decimal adjust before addition
C. decimal adjust accumulator
D. decimal adjust auxiliary
Question 9
The instruction that performs logical AND operation and the result of the operation is not available is
A. AAA
B. AND
C. TEST
D. XOR
Question 10
The instruction that pushes the flag register on to the stack is
A. PUSH
B. POP
C. PUSHF
D. POPF
Question 11
The instruction in which adjustment is made before performing the operation is
A. AAA
B. AAS
C. AAM
D. AAD
Question 12
The instruction that adds immediate data/contents of the memory location specified in an instruction/register to the contents of another register/memory location is
A. SUB
B. ADD
C. MUL
D. DIV
Question 13
The instruction that subtracts 1 from the contents of the specified register/memory location is
A. INC
B. SUBB
C. SUB
D. DEC
Question 14
The instruction that supports addition when carry exists is
A. ADD
B. ADC
C. ADD & ADC
D. None of the mentioned
Question 15
The instruction that unconditionally transfers the control of execution to the specified address is
A. CALL
B. JMP
C. RET
D. IRET
Question 16
The instruction, “INC” increases the contents of the specified register or memory location by
A. 2
B. 0
C. 1
D. 3
Question 17
The instruction that converts the result in an unpacked decimal digits is
A. AAA
B. AAS
C. AAM
D. All of the mentioned
Question 18
The instruction that enables subtraction with borrow is
A. DEC
B. SUB
C. SBB
D. None of the mentioned
Question 19
The instruction that is used as prefix to an instruction to execute it repeatedly until the CX register becomes zero is
A. SCAS
B. REP
C. CMPS
D. STOS
Question 20
The instruction that is used for finding out the codes in case of code conversion problems is
A. XCHG
B. XLAT
C. XOR
D. JCXZ
Question 21
The instruction that is used to convert the result of the addition of two packed BCD numbers to a valid BCD number is
A. DAA
B. DAS
C. AAA
D. AAS
Question 22
The instruction that is used to transfer the data from source operand to destination operand is
A. data copy/transfer instruction
B. branch instruction
C. arithmetic/logical instruction
D. string instruction
Question 23
The instruction that loads effective address formed by destination operand into the specified source register is
A. LEA
B. LDS
C. LES
D. LAHF
Question 24
The instruction that loads the AH register with the lower byte of the flag register is
A. SAHF
B. AH
C. LAHF
D. PUSHF
Question 25
The instruction that loads the flag register completely from the word contents of the memory location is
A. PUSH
B. POP
C. PUSHF
D. POPF
Question 26
The mnemonic that is placed before the arithmetic operation is performed is
A. AAA
B. AAS
C. AAM
D. AAD
Question 27
The instruction, CMP to compare source and destination operands it performs
A. addition
B. subtraction
C. division
D. multiplication
Question 28
The instructions that are used for reading an input port and writing an output port respectively are
A. MOV, XCHG
B. MOV, IN
C. IN, MOV
D. IN, OUT
Question 29
The instructions that are used to call a subroutine from the main program and return to the main program after execution of called function are
A. CALL, JMP
B. JMP, IRET
C. CALL, RET
D. JMP, RET
Question 30
The instructions that involve various string manipulation operations are
A. branch instructions
B. flag manipulation instructions
C. shift and rotate instructions
D. string instructions
Question 31
The ROR instruction rotates the contents of the destination operand to
A. left
B. right
C. left and then right
D. right and then left
Question 32
Which instruction cannot force the 8086 processor out of ‘halt’ state?
A. Interrupt request
B. Reset
C. Both interrupt request and reset
D. Hold
Question 33
Which of the following instruction is not valid?
A. MOV AX, BX
B. MOV DS, 5000H
C. MOV AX, 5000H
D. PUSH AX
Question 34
Which of the following is a mnemonic?
A. ADD
B. ADC
C. AAA
D. ADD & ADC
Question 35
Which of the following is not a data copy/transfer instruction?
A. MOV
B. PUSH
C. DAS
D. POP
Question 36
Which of the following is not a machine controlled instruction?
A. HLT
B. CLC
C. LOCK
D. ESC