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Fundamentals of Computerand programming in C

(CMP 101 )

CENTRAL

PROCESSING UNIT

http://in.groups.yahoo.com/group/shardafundamental14/04/12

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The Central Processing Unit (CPU)

The Central Processing Unit is a silicon chip that

is the brain of of a computer system.

Control unit (CU)

Arithmetic and Logic unit (ALU)

Registers

It executes program instructions and data and

controls all the devices within the machine

Its internal organisation (architecture)

consists of 3 main parts:

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Central Processing Unit

Main Memory (RAM)

FlashProgrammable Read onlyMemory (PROM)Read only Memory(ROM)

Cache Memory

Decoder

Program Control

Register

Instruction Register

Memory Address

Register

Memory Buffer

Register

Input/output Register

General Purpose

Register

Accumulator

Register

General Purpose

Register

General Purpose

Register

I/O

D

E

V

IC

E

s

ALU

Control Unit

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Inside the CPU

Control UnitArithmetic

and Logic

Unit (ALU)

Other

registers

MemoryAddress

Register

Memory

Data

Register

Main

Memory

Address bus

Data bus

Control Bus (Read / Write)

Electronic

clock

Clock pulses

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The Control Unit

It manages fetch, decode andexecute program instructions.

It synchronises the whole system by telling devices what to

do and when to do it

The CU sends signals to other parts of the

computer

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The Arithmetic and Logic Unit

The ALU is where data is actually processed in the CPU

Processing data in the ALU involves doing

arithmetic calculations e.g. add, subtract,

multiply, divide etc.

It also involves logical comparisonslike AND, OR etc. using electronic

circuitry

The ALU uses special arithmetic registers to

temporarily store data and results of calculationse.g. the accumulator

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Instruction SetInstruction

Operation (op) Code Operand

ADD Operand one Operand two

0 0 0 1 1 1 0 0 A R0

Instruction

Accumulat

or register

General Purpose

Register

0 0 0 1 1 1 0 0 0000 0010 0001 0001

0 0 0 1 1 1 0 0 0001 0011 0001 0001

Before execution

After execution

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The Registers

The Registers are very fast storage locations inside the processor itself.

There are many registers including :

memory address register (MAR)

holds the address of a location in

memory

memory data register (MDR) holds

data just read from or written to memory

program counter (PC) holds the

address of the next instruction to be

fetched

Instruction register (IR) holds the

current instruction being executed

general purpose registers can be

used by programmers

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Machine Cycle

Fetch - Calls an instruction into memory

Decode - Figures out what the instruction is trying

to do.

Execute - Does the decoded instruction

Add 2+2

Store - Puts the answer 4 into memory for use by

another instruction

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Clock Cycle

A Crystal Oscillator on the Motherboard

It paces the machine cycle

Measured in MHz or GHz

Megahertz = 1,000,000 cycles/sec

Gigahertz = 1,000,000,000 cycles/sec

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Clock Cycle

One clock cycle is calculated by dividing 1 by the MHz orGHz

Example: (800 MHz CPU)

1/800,000,000 =0.00000000125 or

1.25 nanoseconds (nano = billionth)

(1.25 billionths of a second)

The shorter the clock cycle the faster the processor

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Pipelining

Executing multiple instructions at the same time

FETCHFETCH DECODEDECODE EXECUTEEXECUTE STORESTORE

Instruction 1Instruction 1

Instruction 2Instruction 2

Instruction 3Instruction 3

Instruction 4Instruction 4

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Parallel Processing

Multiple processors work together to complete aset of instructions

Control

CPU

CPU 01

CPU 02

Answer

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Processor Types

CISC :

Complex Instruction Set

Computer.

A set of large number of

variable length instructions.

RISC:

Reduce instruction set

computers.

EPIC:

Explicitly parallel

Instruction

Computing.

1 1 0 0 1 1 0 0

2 0 2 0

2 2

4

ParallelComputation

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Dual-Core

A dual-core CPU combines two independent

processors and their respective caches andcache controllers onto a single silicon chip.

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Dual-Core

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Dual-Core Advantages

Less Power

Less Space

Better Performance

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Dual-Core Disadvantages

Require Different OS

Scalability more limited

Lower production yields

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INTEL

AMD

TRANSMETA

MOTOROLA

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INTEL

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AMD

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TRANSMETA

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MOTOROLA & IBM

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Assignment 01

Explain the difference between the Intel Dual-

Core and AMD Dual-Core CPUS. What makes

them different.

Double-Spaced, 12pt Font, w/References