1.1.1 Architecture Of The CPU

Question 1

Fetch Decode Execute Cycle

Answer 1

Instructions are fetched from the RAM (Random Access Memory)

Instructions are decoded using the CPU’s instruction

Instruction is executed

Cycle is then repeated

Question 2

ALU (Arithmetic Logic Unit)

Answer 2

Carries out arithmetic operations (add, subtract, multiply, divide, shifts)

And logical operations (NOT, AND, OR)

Question 3

CU (Control Unit)

Answer 3

Decodes and execute the instructions

Question 4

Cache

Answer 4

Is very (very) fast memory with a very fast read/write speed - holds recently/frequently used instructions that have been fetched from RAM

Question 5

Register

Answer 5

A very very very small memory circuit

Question 6

Accumulator (ACC)

Answer 6

Temporary store that holds data/instructions that has been inputted form the keyboard or is due to be outputted to the screen, or has been calculated by the ALU

Question 7

Program Counter (PC)

Answer 7

Increments once every fetch decode execute cycle, holding the address of the next instruction to be loaded

Question 8

Memory Address Register (MAR)

Answer 8

Holds the address of the memory location that the processor needs to access (either to read or write data)