1.1.1 (Structure and function of the processor)

Question 1

What is the Harvard architecture?

Answer 1

• Data and instructions are stored and fetched separately
• Can process instructions and data at the same time

Question 2

Compare Von Neumann and Harvard architecture

Answer 2

• Von Neumann is adaptable and conventional
• Harvard is faster and more complex

Question 3

What is an address bus?

Answer 3

• Transmits the address of data to be loaded from the CPU to memory
• Carries the location to read/write data
• It goes one way

Question 4

What is a data bus?

Answer 4

• Transmits data between components
• Goes both directions

Question 5

What is a control bus?

Answer 5

• Transmits command, timing, and status information between components

Question 6

What is assembly language?

Answer 6

• A low level programming language
• Each command maps directly to a machine code instruction

Question 7

Describe what happens in the “fetch” part of the fetch-execute cycle?

Answer 7

• The address of the instruction to be fetched is placed into the MAR.
• The instruction is fetched from memory. - - The instruction is transferred to the MDR.

Question 8

Describe what happens in the “decode” part of the fetch-execute cycle?

Answer 8

The instruction is decoded

Question 9

Describe what happens in the “execute” part of the fetch-execute cycle?

Answer 9

The decoded instruction is then executed so that the CPU performs continuously

Question 10

Describe what happens at the end of the fetch execute cycle?

Answer 10

• The process is repeated
• The program counter is incremented

Question 11

What operations does the ALU perform?

Answer 11

Arithmetic and logic operations

Question 12

What does the Control Unit (CU) do?

Answer 12

• Sends signals to control the fetch execute cycle.
• Co-ordinates the flow of data through the CPU

Question 13

What is a CPU register?

Answer 13

• The section of high-speed memory within the CPU that stores data to be processed

Question 14

State two features of the MAR?

Answer 14

• It is a register
• It stores a single address

Question 15

What is the function of the MAR?

Answer 15

• Stores the address of the instruction that is going to be fetched
• Holds the address in memory where data is going to be transferred to

Question 16

What is the function of the MDR?

Answer 16

Stores the fetched instruction/ the instruction to be processed

Question 17

What is the function of the Program Counter?

Answer 17

Stores the address of the next (or current) instruction to be run

Question 18

What is the function of the Accumulator?

Answer 18

Stores the result of calculations/processes

Question 19

Why does cache size affect the performance of the CPU?

Answer 19

• Data is transferred faster
• Makes the CPU more efficient

Question 20

How can having a higher processor affect the performance of the CPU?

Answer 20

• Faster/ Higher clock speed
• More Fetch Execute Cycles
• More Instructions can be executed per second

Question 21

Explain why having a quad- core processor will not always run twice as fast as a dual- core processor?

Answer 21

• Software may be designed to run 1 core and not multiple
• Dual core may have a faster clock speed than a quad core
• Quad core may have less RAM
• Quad core may have less cache

Question 22

What is Cache Memory?

Answer 22

High speed memory inside the processor that stores frequently used instructions

Question 23

What is machine code?

Answer 23

• A binary programming language used by a CPU
• All code is eventually converted to machine code
• Unique to each CPU type

Question 24

What is the Stored Program Concept?

Answer 24

• Instructions and data are stored in memory together

Question 25

What is operand?

Answer 25

- Data for the CPU to run an instruction on

Question 26

What is opcode?

Answer 26

- Operation code: an instruction for the CPU to process

Question 27

What is a CIR?

Answer 27

- Current Instruction Register - Holds the current instruction, divided into operand and opcode