Computer Engineering

Rabie A. Ramadan

Lecture 1

2

Welcome Back

Organization of the Course

3

Two Lectures weekly

Evaluation is based on: • Midterm and Final Exams

• Assignments

• In class group activities almost every lecture

Organization of the Course (Cont.)

4

Textbooks • Mostafa Abd-El-Barr and Hesham El-Rewini,

Fundamentals of computer Organization and

architecture, Wiley interscience, 2005.

•

Class Rules

5

Attendance is a mandatory

Assignments must be delivered on time

Assignments must be submitted in electronic format no papers will be accepted

Things need to be with you in class

6

• For the group activities

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.

9

Hit

4 * 5 + 3* 6 = 38

8 * 4 + 3 * 5 = 47

Video Part

10

Play

What does it tell you?

Be Smart and Think Smartly

Table of Contents

Introduction

Historical Development

Computer Hierarchy

The Von Neumann Model

Architecture Development and Styles

Introduction

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?

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

It is not easy to separate computer organization issues from computer architecture issues due to:

Principle of Equivalence of Hardware and Software• 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:

• 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.)

Human being brain Processor

Writing notes saving data in the memory

Pencil or pen used to write is the I/O mechanism

Computer Development and Moore's Law

New devices are invented almost every day

Technology became smaller and smaller

Millions of transistors on a chip.

Where it ends ?

How small can we make transistors?

How densely can we pack chips?

Computer Development and Moore's Law (Cont.)

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. • 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.)

Level 6 (the User Level):• 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):• Languages such as C, C++, FORTRAN, Lisp, Pascal, and Prolog.

Level 4(the Assembly Language Level):• compiled higher-level languages are first translated to assembly, which is then directly

translated to machine language.

Level 3 (the System Software Level)• deals with operating system instructions.

• responsible for multiprogramming, protecting memory, synchronizing processes, and various other important functions

Computer Level Hierarchy (Cont.)

Level 2 (Instruction Set Architecture (ISA) or Machine Level)

• The machine language recognized by the particular architecture of the computer system.

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.

Level 0 (Digital Logic)

• Computer Hardware

The Von Neumann Model

The system passes all of its I/O through

the arithmetic logic.

It uses von Neumann execution cycle

(also called the fetch-decode-execute cycle)

The Von Neumann Model (Cont.)

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

Decode instruction

Evaluate address

Fetch operands from memory

Execute operation

Store result

Fetch instruction from memory

The Modified Von Neumann Model

The data bus: Moves data from main memory

to the CPU registers (and vice versa).

The address bus: Holds the address of the data that

the data bus is currently accessing.

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

Performance is the main goal of any architecture• Complex instructions

• Reduces the number of instructions to be used

• Small number of instructions to perform a job.

• Using different addressing modes that fits the required task

• Examples: • Complex Instructions Set Computers (CISCs) such as :

• Intel PentiumTM,

• Motorola,

• MC68000TM,

• and the IBM & Macintosh PowerPCTM.

Architecture Development and Styles (Cont.)

Speeding up some of the effective instructions• More than 80% of the instructions executed are those using:

• Assignment statements, conditional branching and procedure calls.

• Simple assignment statements constitute almost 50% of those operations.

• Optimizing such instructions enhances the performance

• Example:

• Reduced Instructions Set Computers (RISCs) such as:

• Sun SPARCTM and MIPS machines.