CPU Components & Their Function
What is the Von Neumann architecture?
- The Von Neumann Architecture is a design of the CPU which was proposed by Mathematician John Von Neumann in the 1940s, which most general-purpose computers are built upon
- The Von Neumann Architecture outlines how the computer memory, input / output devices and processor all work together
What are the components of the CPU?
- The CPU is made up of 5 key components
- Arithmetic Logic Unit (ALU)
- Control Unit (CU)
- Clock
- Registers
- Bus
- Each of the components sits within the CPU
What is the function of each component?
Arithmetic logic unit (ALU)
- Performs arithmetic operations
- Performs logical decisions
- IF X > 5 THEN
DO ……….
- IF X > 5 THEN
Control unit (CU)
- Coordinates how data moves around the CPU by sending a signal to control the movement of the data
- Decodes the instructions fetched from memory
Clock
- Keeps related components in sync by generating pulses at a constant rate
Registers
- Extremely small, extremely fast memory located in the CPU
- Hold small amounts of data needed as part of the fetch-execute cycle
- Each register has its own specific purpose
- Accumulator (ACC) - stores results of logical or arithmetic calculations carried out by the ALU
- Memory address register (MAR) - stores the address of the next instruction to be fetched from RAM
- Memory data register (MDR) - stores the data retrieved from RAM
- Program counter (PC) - stores the memory address of the next instructions to be executed & Increments by 1 as the fetch-decode-execute cycle runs
Bus
- A bus is a collection of wires through which data/signals are transmitted from one component to another