Lahore Leads University 923224907404

2. Introduction :
Name : Muhammad Ashib Altaf.
Registration number : F12-1028-(A)

3. Presentation Topics
 Central  Registers
Processing Unit
(CPU)  Instruction
Set
 Control Unit
(CU)  Processor
Speed
 Arithmetic
Logic Unit  Types of
(ALU) Processor

4. 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)

5. 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.

6. Operations of Arithmetic Logic Unit (ALU) :
• The ALU (Arithmetic/Logic Unit) performs.
• Mathematical operations (+, -, x, /, ^,…)
• Logic operations (=, <, >, and, or, not, ...)

7. 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.

8. Basic Cycle of Control Unit :

9. 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

10. Functions of the control unit

11. 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.

12. Functions of commonly used Registers:

13. CPU and main memory connected via a
bus
2-13

14. 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.

15. Processor Speed:
• Normally, several clock cycles are
required to Fetch, Decode, and
Execute a single program instruction.
• Shorter the clock cycle, Faster the
processor.

16. Types of Processor:

17. Types of Processor:

18. Types of Processor: