The document discusses the central processing unit (CPU). It describes the CPU as the multipurpose, programmable component of a computer that interprets instructions and performs logical and arithmetic operations. The CPU is composed of an arithmetic logic unit (ALU) that performs calculations, a control unit (CU) that directs signals between memory and the ALU, and register arrays that temporarily store processed data. Factors like clock rate, memory size, and instruction set complexity can impact a CPU's processing speed. The CPU executes a cycle of fetching instructions from memory, decoding them, executing operations, and storing results.

1. CENTRAL PROCESSING UNIT
(CPU)
P R E PA R E D B Y
P R A B I N M A H A R J A N
B I M 1 S T S E M E S T E R
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2. CONTENTS:
 I N T R O D U C T I O N O F C P U
 F U N C T I O N O F C P U
 C O M P O N E N T S O F T H E C P U
 FA C TO R S A F F E C T I N G P R O C E S S I N G S P E E D
 C P U C Y C L E
 C O N C L U S I O N
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3. INTRODUCTION
 It is a multipurpose, programmable, clock-driven, register based semiconductor
device
 CPU interprets instructions to the computer, performs the logical and arithmetic
processing operations, and causes the input and output operations
 First CPU was made in the 1940s and was ran with the first computer the
EDVAC
 It is made up of silicon chip which normally contains millions of transistors.
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5. FUNCTION OF CPU
 To carry out processing.
 To perform arithmetic calculation such as addition, subtraction.
 To read instruction & data from memory.
 To communicate with peripherals using system bus.
 To give commands to all parts of the computer system.
 To control the timing of information flow.
 To control the storage of data or instruction.
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6. COMPONENTS OF CPU
1. ALU (Arithmetic Logic Unit)
2. CU (Control Unit)
3. Register Array
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7. ALU (ARITHMETIC LOGIC UNIT)
 ALU performs arithmetic and logic operations such as addition,
subtraction, multiplication, division, shifting operations and logic
instructions
 ALU includes a group of register-high speed memory locations built
directly into the CPU that holds the data currently being processed
which is known as Accumulator
 ALU also perform operation like increment, decrement etc.
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8. CU (CONTROL UNIT)
 CU directs the moment of electronic signals between main memory and
ALU
 It acts as the nerve center of the computer system
 It provides the necessary timing and control signals to all the
operations in the computer
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9. REGISTER ARRAY
 Register is the special purpose temporary storage locations inside the
CPU that holds data that is being processed
 It generally occupy the top-most position in the memory hierarchy,
providing high-speed and fast access
 It is normally made of static or dynamic random access memory (RAM)
cells
 E.g.
• Accumulator
• Address Register
• Instruction register
• Sequence register
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10. FACTORS AFFECTING PROCESSING SPEED
 Clock rate of the CPU
 Computer word size
 Bus speed
 Main memory size
 Cache memory size
 Instruction set complexity
 Number of processing units
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11. CPU CYCLE
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FETCHING
EXECUTING
STORING DECODING

12. CONCLUSION
 Thus CPU is the main part (brain) of the computer system
 It controls the operation of all other components such as memory, input and
output device
 It interprets instructions to the computer, performs the logical and arithmetic
operations
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13. THANK YOU
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