Introduction : Name : Muhammad Ashib Altaf. Registration number : F12-1028-(A)
Presentation Topics Central Registers Processing Unit (CPU) Instruction Set Control Unit (CU) Processor Speed Arithmetic Logic Unit Types of (ALU) 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.
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
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.
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.