Transcript Session 1

Computer Engineering
Rabie A. Ramadan
Lecture 1
Welcome Back
2
Organization of the Course
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Two Lectures weekly
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Evaluation is based on:
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Midterm and Final Exams
Assignments
In class group activities  almost every lecture
3
Organization of the Course (Cont.)
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Textbooks
Mostafa Abd-El-Barr and Hesham El-Rewini,
Fundamentals of computer Organization and
architecture, Wiley interscience, 2005.
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4
Class Rules
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Attendance is a mandatory
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Assignments must be delivered on time
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Assignments must be submitted in electronic format  no
papers will be accepted
5
Things need to be with you in class
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For the group activities
6
Before we start ….
Lets have a group activity for 2 minutes
Game No. 1
Study the circles below.
Work out what number should replace the question
mark.
Hit
4 * 5 + 3* 6 = 38
8 * 4 + 3 * 5 = 47
9
Video Part
Play
What does it tell you?
Be Smart and Think Smartly
10
Table of Contents

Introduction

Historical Development
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Computer Hierarchy
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The Von Neumann Model

Architecture Development and Styles
Introduction
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Computer Architecture :
• Focuses on the structure and behavior of the computer system
• Refers to the logical aspects of system implementation as seen by
the programmer.
• How do I design a computer?
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Computer Organization:
• Focuses on the relationship exists between computer hardware
and many aspects of programming and software components in
computer systems.
• How does a computer work?
Introduction
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It is not easy to separate computer organization issues from computer
architecture issues due to:
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Principle of Equivalence of Hardware and Software
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Anything that can be done with software can also be done with hardware,
Anything that can be done with hardware can also be done with software.
A computer is a device consisting of three pieces:
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A processor to interpret and execute programs
A memory to store both data and programs
A mechanism for transferring data to and from the outside world
Main Components of a Computer (Cont.)
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Human being brain  Processor
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Writing notes  saving data in the memory
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Pencil or pen used to write is the I/O mechanism
Computer Development and Moore's Law
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New devices are invented almost every day
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Technology became smaller and smaller
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Millions of transistors on a chip.
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Where it ends ?
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How small can we make transistors?
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How densely can we pack chips?
Computer Development and Moore's Law
(Cont.)
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In 1965, Intel founder Gordon Moore stated,
"The density of transistors in an integrated circuit will double every
year."
The current version of this prediction is usually conveyed as
"the density of silicon chips doubles every 18 months."
Moore's Law cannot hold forever.
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Moore intended this postulate to hold for only 10 years
There are physical and financial limitations that must ultimately come into play.
Computer Level Hierarchy
Computer Level Hierarchy (Cont.)
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Level 6 (the User Level):
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Composed of applications and is the level with which everyone is most familiar.
Examples: Word, graphics , and games.
Level 5 (The High-Level Language Level):
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Languages such as C, C++, FORTRAN, Lisp, Pascal, and Prolog.
Level 4(the Assembly Language Level):
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compiled higher-level languages are first translated to assembly, which is then directly
translated to machine language.
Level 3 (the System Software Level)
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deals with operating system instructions.
responsible for multiprogramming, protecting memory, synchronizing processes,
and various other important functions
Computer Level Hierarchy (Cont.)
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Level 2 (Instruction Set Architecture (ISA) or Machine Level)
• The machine language recognized by the particular architecture of
the computer system.
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Level 1(Control Level)
• Where a control unit makes sure that instructions are decoded and
executed properly and that data is moved where and when it
should be.
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Level 0 (Digital Logic)
• Computer Hardware
The Von Neumann Model
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The system passes all of
its I/O through
the arithmetic logic.
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It uses von Neumann
execution cycle
(also called the fetchdecode-execute cycle)
The Von Neumann Model (Cont.)
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A cycle could be as follows:
1.
The control unit fetches the next program
instruction from the memory, using the program
counter to determine where the instruction is
located.
2.
The instruction is decoded into a language the
ALU can understand.
3.
Any data operands required to execute the
instruction are fetched from memory and placed
into registers within the CPU.
4.
The ALU executes the instruction and places the
results in registers or memory.
Instruction Processing
Von Neumann execution cycle
Fetch instruction from memory
Decode instruction
Evaluate address
Fetch operands from memory
Execute operation
Store result
The Modified Von Neumann Model
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The data bus:
Moves data from main memory
to the CPU registers (and vice versa).
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The address bus:
Holds the address of the data that
the data bus is currently accessing.
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The control bus:
Carries the necessary control signals that specify how the
information transfer is to take place.
Did we
gain
something
?
Architecture Development and Styles
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Performance is the main goal of any architecture
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Complex instructions
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Reduces the number of instructions to be used
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Small number of instructions to perform a job.
Using different addressing modes that fits the required task
Examples:
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Complex Instructions Set Computers (CISCs) such as :
• Intel PentiumTM,
• Motorola,
• MC68000TM,
• and the IBM & Macintosh PowerPCTM.
Architecture Development and Styles (Cont.)
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Speeding up some of the effective instructions
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More than 80% of the instructions executed are those using:
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Assignment statements, conditional branching and procedure calls.
Simple assignment statements constitute almost 50% of those
operations.
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Optimizing such instructions enhances the performance
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Example:
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Reduced Instructions Set Computers (RISCs) such as:
Sun SPARCTM and MIPS machines.