Test: Basic Operational Concept - Computer Science Engineering (CSE) MCQ

Answer: a
Explanation: The instruction after obtained from the PC, is decoded and operands are fetched and stored in the IR.

1. Understanding the Components:

• LOCA: This is a label or memory address that holds a value. In assembly language, labels like LOCA are used to refer to specific locations in memory.
• R0: This is a register, which is a small, fast storage location within the CPU.

2. Operation of ADD LOCA, R0:

• Fetch the Value: The instruction fetches the value stored at the memory address specified by LOCA.
• Add the Values: It then adds this value to the current value stored in the register R0.
• Store the Result: The result of the addition is stored back into register R0.

3. Detailed Explanation:

• Before the Instruction: Suppose the value at LOCA is 5 and the value in R0 is 10.
• During Execution: The instruction adds the value at LOCA (5) to the value in R0 (10).
• After Execution: The new value of R0 will be 15, which is the sum of 5 and 10.

Summary

The instruction ADD LOCA, R0 results in the value at LOCA being added to the value in R0, and then the result is stored back into R0. This means R0 will contain the sum of its original value and the value from LOCA after the instruction executes.

This is why the correct answer is:

3. Adds the values of both LOCA and R0 and stores it in R0

Answer: a
Explanation: MAR can interact with secondary storage in order to fetch data from it.

3. PC (Program Counter)

Explanation:

During the execution of a program, the Program Counter (PC) is initialized first. The PC holds the address of the next instruction to be executed, so it must be initialized before the program starts executing. The processor fetches the instruction from memory based on the address stored in the PC.

Once the instruction is fetched, other components like the Memory Address Register (MAR), Memory Data Register (MDR), and Instruction Register (IR) are used in subsequent steps of instruction execution. But the PC is the first to be initialized to point to the starting instruction of the program.

Answer: b
Explanation: MAR is connected to the memory BUS in order to access the memory

Answer: b
Explanation: The processor BUS is used to connect the various parts in order to provide a direct connection to the CPU.

Answer: b
Explanation: The multiplexer circuit is used to choose between the two as it can give different results based on the input.

Answer: d
Explanation: The Operational and processing part of the CPU are collectively called as data path.