Registers and Common CPU Components [1.3]

Question 1

What does the Program Counter do?

Answer 1

The Program Counter stores the address of the next instruction.

Question 2

What does the Memory Address Register do?

Answer 2

Holds the address of the current instruction.

Question 3

What does the Memory Data Register do?

Answer 3

The Memory Data Register (MDR) stores the actual data of the instruction.

Question 4

What does the Current Instruction Register do?

Answer 4

Holds Opcode and Operand

Question 5

What does the Accumulator do?

Answer 5

Temporarily stores the arithmetic result.

Question 6

What does the ALU (Arithmetic Logic Unit) do?

Answer 6

Performs arithmetic and logical units (decisions). The ALU is where calculations are done and where decisions are made.

It acts as a gateway between primary memory and secondary storage . Data transferred between them passes through the ALU.

Question 7

What does the Control Unit (CU) do?

Answer 7

Fetches, decodes and executes instructions.
Issues control signals that control hardware.
Moves data around system.