8086 Microprocessor - Short Questions

What is a Microprocessor?

• A) A device that converts analog signals to digital signals
• B) A central processing unit on a single chip
• C) A memory storage unit used in computers
• D) A device that controls input/output operations in computers

Answer explanation

A microprocessor is an integrated circuit that contains the functions of a central processing unit (CPU) of a computer.

Which of the following is NOT a feature of the 8086 microprocessor?

• A) 16-bit data bus
• B) 20-bit address bus
• C) Memory segmentation
• D) Built-in floating-point arithmetic

Answer explanation

8086 has a 16-bit data bus, 20-bit address bus, and supports memory segmentation. However, it does not have built-in floating-point arithmetic.

Which of the following is NOT a status flag in the 8086 microprocessor's flag register?

• A) Carry Flag (CF)
• B) Parity Flag (PF)
• C) Overflow Flag (OF)
• D) Program Counter (PC)

Answer explanation

The Program Counter (PC) is not a flag but a register. Flags include Carry Flag, Parity Flag, etc.

What is the main function of the Instruction Pointer (IP) in the 8086 microprocessor?

• A) Stores data temporarily
• B) Points to the next instruction to be executed
• C) Holds the address of the top of the stack
• D) Manages interrupts and exceptions

Answer explanation

The Instruction Pointer holds the address of the next instruction to be executed.

What does the ADD instruction in the 8086 microprocessor do?

• A) Subtracts two numbers
• B) Compares two values
• C) Adds two values and stores the result
• D) Transfers data from one register to another

Answer explanation

The ADD instruction adds two operands and stores the result.

Which mode allows the 8086 microprocessor to operate as a single processor without external coprocessors?

• A) Minimum mode
• B) Maximum mode
• C) User mode
• D) Privileged mode

Answer explanation

Minimum mode is for single processor systems.

What is the purpose of the maximum mode in the 8086 microprocessor?

• A) To reduce power consumption
• B) To support multiple processors
• C) To enhance memory access speed
• D) To execute privileged instructions

Answer explanation

Maximum mode is for systems with multiple processors or coprocessors.

Which of the following flags in the 8086 flag register indicates that the result of an operation generated a carry from the most significant bit?

• A) Zero Flag (ZF)
• B) Carry Flag (CF)
• C) Parity Flag (PF)
• D) Sign Flag (SF)

Answer explanation

Carry Flag (CF) is set when an operation generates a carry out from the most significant bit.

What is the function of the Direction Flag (DF) in the 8086 microprocessor?

• A) It indicates the direction of data transfer in string operations
• B) It controls the execution of branching instructions
• C) It stores the result of an arithmetic operation
• D) It enables or disables interrupts

Answer explanation

The Direction Flag controls string operation data transfer direction.

Which instruction in the 8086 instruction set is used to perform a bitwise AND operation?

• A) OR
• B) XOR
• C) AND
• D) NOT

Answer explanation

The AND instruction performs a bitwise AND between two operands.