Function and structure of the Processor

Question 1

Arithmetic and Logic Unit

Answer 1

Component of the processor, which is responsible for all arithmetical and logical operations.

Question 2

What are Arithmetic operations?

Answer 2

All mathematical operations such as addition and subtraction on fixed or floating point numbers.

Question 3

Control Unit

Answer 3

Component of the processor which directs the operations of the CPU.

Question 4

What does CU stand for?

Answer 4

Control Unit

Question 5

What are the roles of the CPU?

Answer 5

• Controlling and coordinating the activities of the CPU
• Managing the flow of data between the CPU and other devices
• Accepting the next instruction
• Decoding instructions
• Storing the resulting data back in memory

Question 6

Registers

Answer 6

Small memory cells that operate at a very high speed.

Question 7

What is a register?

Answer 7

Small memory cells that operate at a very high speed.

Question 8

What is the purpose of a register?

Answer 8

Temporarily store data and all arithmetic, logical and shift operations occur in these register.

Question 9

What are the 5 types of registers?

Answer 9

Program counter
Accumulator
Memory data register
Memory address register
Current instruction register

Question 10

What does PC stand for?

Answer 10

Program counter

Question 11

What is a program counter?

Answer 11

The program counter holds the address of the next instruction to be executed.

Question 12

What does ACC stand for?

Answer 12

Accumulator

Question 13

What is an Accumulator?

Answer 13

Stores the results of the ALU

Question 14

What is a Logical operations?

Answer 14

Boolean logic operations such as AND, OR, NOT, XOR. NAND and NOR.

Question 15

Memory data register

Answer 15

Temporarily stores data that has been read

or data that needs to be written

Question 16

Memory address register

Answer 16

Holds the address of a location that is to be read from or written to.

Question 17

What does MDR stand for?

Answer 17

Memory data register

Question 18

What does MAR stand for?

Answer 18

Memory address register

Question 19

What does CIR stand for?

Answer 19

Current instruction register

Question 20

Current instruction register

Answer 20

Holds the current instruction being executed, divided up into operand and opcode.

Question 21

What is a bus?

Answer 21

A set of parallel wires, which connect 2 or more components inside the CPU. There are three buses in the CPU: data bus, control bus, and address bus. These buses collectively are called the system bus.

Question 22

What is a data bus?

Answer 22

Bi-directional bus (meaning bits can be carried in both directions). This is used for transporting data and instructions between components.

Question 23

What is an address bus?

Answer 23

This is the bus used to transmit the memory addresses specifying where data is to be sent to or retrieved from. The width of the address bus is proportional to the number of addressable memory locations.

Question 24

The control signals include

Answer 24

The control signals include:

• Bus request: shows that a device is requesting the use of the data bus
• Bus grant: shows that the CPU has granted access to the data bus
• Memory write: data is written into the addressed location using this bus
• Memory read: data is read from a specific location to be placed onto the data bus,
• Interrupt request: shows that a device is requesting access to the CPU
• Clock: used to synchronize operations