Engineering Questions with Answers - Multiple Choice Questions

MCQs on 8051 Instruction Set -1

1 - Question

Which of the following is not an instruction of 8051 instructions?
a) arithmetic instructions
b) boolean instructions
c) logical instructions
d) none

View Answer

Answer: d
Explanation: The 8051 instructions are categorized as
1. Data transfer instructions
2. Arithmetic instructions
3. Logical instructions
4. Boolean instructions
5. Control transfer instructions.




2 - Question

The operations performed by data transfer instructions are on
a) bit data
b) byte data
c) 16-bit data
d) all of the mentioned

View Answer

Answer: d
Explanation: The data transfer instructions implement a bit, byte, 16-bit data transfer operations between the SRC(source) and DST(destination) operands.




3 - Question

Which of the following is true while executing data transfer instructions?
a) program counter is not accessible
b) restricted bit-transfer operations are allowed
c) both operands can be direct/indirect register operands
d) all of the mentioned

View Answer

Answer: c
Explanation: In data transfer instructions,
1. Program counter is not accessible.
2. Restricted bit-transfer operations are allowed.
3. Both operands can be direct/indirect register operands.
4. BOth operands can be internal direct data memory operands.




4 - Question

The logical instruction that affects the carry flag during its execution is
a) XRL A;
b) ANL A;
c) ORL A;

View Answer

Answer: d
Explanation: The logical instructions that doesn’t affect the carry flag are, ANL, ORL and XRL. The logical instructions that affect the carry flag during its execution are RL, RLC, RRC and RR.




5 - Question

The instruction that is used to complement or invert the bit of a bit addressable SFR is
a) CLR C
b) CPL C
c) CPL Bit
d) ANL Bit

View Answer

Answer: c
Explanation: The instruction, CPL Bit is used to complement or invert the bit of a bit addressable SFR or RAM.




6 - Question

The instructions that change the sequence of execution are
a) conditional instructions
b) logical instructions
c) control transfer instructions
d) data transfer instructions

View Answer
Answer: c
Explanation: The control transfer instructions transfer the control of execution or change the sequence of execution conditionally or unconditionally.

 




7 - Question

The control transfer instructions are divided into
a) explicit and implicit control transfer instructions
b) conditional and unconditional control transfer instructions
c) auto control and self control transfer instructions
d) all of the mentioned

View Answer

Answer: b
Explanation: The control transfer instructions are divided into conditional and unconditional control transfer instructions.




8 - Question

The conditional control transfer instructions check a bit condition which includes any bit of
a) bit addressable RAM
b) bit addressable SFRs
c) content of accumulator
d) all of the mentioned

View Answer
Answer: d
Explanation: The conditional control transfer instructions check a bit condition which includes any bit of bit addressable RAM or bit addressable SFRs or content of accumulator for transferring the control to the specified jump location.

 




9 - Question

All conditional jumps are
a) absolute jumps
b) long jumps
c) short jumps
d) none

View Answer
Answer: c
Explanation: All conditional jumps are short jumps.

 




10 - Question

The first byte of a short jump instruction represents
a) opcode byte
b) relative address
c) opcode field
d) none

View Answer

Answer: a
Explanation: The short jump instruction has two byte instruction. The first byte represents opcode byte and second byte represents an 8-bit relative address.




11 - Question

In logical instructions, the immediate data can be an operand for
a) increment operation
b) decrement operation
c) single operand instruction
d) none

View Answer
Answer: d
Explanation: In logical instructions, the immediate data can’t be an operand for increment/decrement or any other single operand instruction.

 

Get weekly updates about new MCQs and other posts by joining 18000+ community of active learners