General Features of a Processor

The processor is the most active part of the motherboard, which carries out the instruction of a program. The processor is often called Central Processing Unit (CPU) and involved in numerous activities related to instruction execution. It can be an arithmetic calculation, a text manipulation, I/O signal control or a memory space management.

Structural Components of CPU

CPU comprises of 2 main parts, data path and control.

Data path: 

Considered as the hardware that performs all required operations, and consists of ALU, registers and internal buses. Data path is the brawn (strength) of the computer.

Control: 

The hardware which instructs the data path about what needs to be done. This is considered to be the brain of the computer.

Control Unit: 

Fetches and decodes instructions.

ALU: 

Performs basic operations needed to carry out instructions.

Registers: 

Local storage locations (to acquire high speed memory) used to store temporary results and control information during instruction execution

A register is allocated a certain number of bits. Normally, the register size corresponds with the word size. Word size is considered to be a determining factor when considering the capability of a computer. Thus the word size relates with the architecture of the processor. Internal register size, 16 bits or 32 bits contribute for 16- bit- architecture and 32-bit architecture respectively.

Special Purpose Registers:

1. Program Counter: contains the address of the next instruction to be fetched from memory during program execution.
2. Instruction Register: Holds the currently executed instruction.
3. Data Registers: Hold data values during instruction execution.