Introduction :

Name : Muhammad Ashib Altaf.

Registration number : F12-1028-(A)

Presentation Topics

Central Processing Unit (CPU)

Control Unit (CU)

Arithmetic Logic Unit (ALU)

Registers

Instruction Set

Processor Speed

Types of Processor

Central Processing Unit (CPU)

• The brain of computer system.

• Performs all major calculations and comparisons.

• Activates and controls the operations of other units of a computer system.

• Two basic components are:

1. Arithmetic Logic Unit (ALU)2. Control Unit (CU)

Arithmetic Logic Unit (ALU) :

• In computing, an arithmetic logic unit (ALU) is a digital circuit that performs arithmetic and logical operations.

• Now, modern microprocessors, microcontrollers and CPUs have very powerful and very complex ALUs, also a CPU may contain up to more than 4 ALUs.

Operations of Arithmetic Logic Unit (ALU) :

• The ALU (Arithmetic/Logic Unit) performs.

• Mathematical operations (+, -, x, /, ^,…)

• Logic operations (=, <, >, and, or, not, ...)

Control Unit:

• One of the two basic components of CPU.

• Acts as the central nervous system of a computer system.

• Selects and interprets program instructions, and coordinates execution.

• Has some special purpose registers and a decoder to perform these activities.

Basic Cycle of Control Unit :

Structure of the Control Unit :

• PC (Program Counter):◦stores the address of next instruction to fetch

• IR (Instruction Register):◦stores the current instruction.

• Instruction Decoder:◦Decodes instruction and activates

necessary circuitry

Functions of the control unit

Registers:

• Special memory units , called registers are used to hold information on a temporary bases as the instructions are interpreted and executed by the CPU.

• Registers are part of the CPU of a computer.

• The length of a register , also known Word Size , equals the numbers of bits it can store.

• CPU with 32bit register can process data twice larger than one with 16bit register.

Functions of commonly used Registers:

CPU and main memory connected via a bus

2-13

Processor Speed:

• A computer has a built-in system Clock that emits millions of regularly spaced electric pulses per second(known as clock cycles)

• It takes one cycle to perform a basic operation, such as moving a byte of data from one memory location to another.

Processor Speed:

• Normally, several clock cycles are required to Fetch, Decode, and Execute a single program instruction.

• Shorter the clock cycle, Faster the processor.

Types of Processor:

Types of Processor:

Types of Processor: