1. COMPUTER ORGANZIATION AND ASSEMBLY LANGUAGE
Abdul Mannan

2. Course Objectives
After successfully completing this course, you will be able to:
Describe the basic components of a Computer System, its instruction set architecture and its basic fetch-execute cycle operation.
Describe how data is represented and recognized in a Computer.
Understand the basics of Assembly Language programming including addressing modes, subroutines, interrupts, stacks, etc.
Analyze, design, implement, and test assembly language programs.

3. Course is About What computers are consist of? How computers work?
How to represent information?
How they are organized internally?
How design affects programming and applications?
Programming the machine: Assembly Language

4. Text Books to Follow
Assembly Language for x86 Processors ,6th Ed. Kip R. Irvine , Prentice Hall ,2010
Computer Organization & Design: The Hardware/Software Interface, 4th Ed. David Peterson & John Hennessy 2008
Computer organization and Architecture by William Stallings

5. Subject Schema The course is divided into two sections:
Computer Organization: describes how different components fit together to create working computer system.
Assembly Language: programming language that uses symbolic names to represent operations, registers and memory locations.

6. Computing Machines Computing machines are ubiquitous.
General Purpose: Servers, desktops, laptops, PDAs, etc.…
Special Purpose: Cash register, ATMs, Games, Mobile Phones, etc.
Embedded: Cars, door lock, printers, digital players, industrial machinery, medical equipment, etc.

7. Computer Software Hardware Program consists Electronics circuit boards
of sets of instructions
that control the system
Hardware
Electronics circuit boards
that provide
functionality of the system

8. Inside the Computer
System software: provides services that are commonly useful, including
Operating system
Handling input/output
Managing memory and storage
Scheduling tasks & sharing resources
Translators: translates HLL code to machine code
Application software: written in HLL.

9. Moore’s Law In 1965, Intel founder Gordon Moore stated:
“The number of transistors per square inch in an integrated circuit will double every year”
Current version of Moore’s Law predicts doubling of density of silicon chips every 18 months.
Moore originally thought this postulate would hold for 10 years; advances in chip manufacturing processes have allowed the law to hold for 40 years, and it is expected to last for perhaps another 10

10. Abstraction Complete definition of abstraction includes the following:
Suppression of detail
Outline structure
Division of responsibility
Subdivision of system into smaller subsystems

11. Abstraction and Computer System
Can look at a computer as being a machine composed of a hierarchy of levels.
Each level has specific function
Each level exists as a distinct imaginary machine (or virtual machine)
Each level’s virtual machine executes its own particular set of instructions, calling upon machines at lower levels to carry out tasks as necessary

12. Abstraction and Computer Systems
Machine-independent
Text uses the following labels to describe levels of abstraction in a computer system:
App7 HOL6 Asmb5 OS4 ISA3 Mc2 LG1
Each level has its own language to describe tasks performed by Computer
Machine-specific

13. Abstraction and Computer Systems
Level: App7
The application level is composed of those programs designed to do specific kinds of tasks for end users.
An application may have some sort of programming language associated with it (macros or shortcuts, e.g.)
Ideally, end users need not be concerned with the actions and language(s) associated with lower levels in the abstraction hierarchy.

14. Abstraction and Computer Systems
Level: HOL6
The high order language layer is the layer of abstraction at which most programmers operate.
Applications are typically written in high order languages.
High order languages are characterized by:
Portability across platforms.
Relative ease of use.
Relatively high level of abstraction, requiring translation of program code prior to execution.

15. Abstraction and Computer Systems
Level: Asmb5
The assembly language level is an intermediate step between high order language and the machine language of a particular processor.
Programs at the HOL6 level are usually compiled to level Asmb5, then translated (assembled) to machine language.
Source code can also be written in assembly language.

16. Abstraction and Computer Systems
Level: OS4
The operating system is responsible for the tasks related to multiprogramming, including:
Memory protection
Process synchronization
Device management
Operating systems were originally developed for multiuser systems, but even most single user systems utilize an operating system.
Compilers and assemblers are also considered systems software.

17. Abstraction and Computer Systems
Level: ISA3
The instruction set architecture, or machine language level, consists of the set of instructions recognized by the particular hardware platform.
Instructions at this level are directly executable without any translation.

18. Abstraction and Computer Systems
Level: Mc2
The microinstruction or control level is the level at which the computer decodes and executes instructions and moves data in and out of the processor.
The processor’s control unit interprets machine language instructions, causing required actions to take place.

19. Abstraction and Computer Systems
Level: LG1
The digital logic level consists of the physical components of the computer system, the actual electronic gates and wires.
Boolean algebra and truth tables can be used to describe the operations at this level.

20. Functions of a Computer
Functions of all computers are:
Data processing
Data storage
Data movement
Control

21. Functions of a Computer
Data Movement
e.g. Keyboard to screen

22. Functions of a Computer
Storage
e.g. Internet download to Hard Disk

23. Functions of a Computer
Processing from/to storage
e.g. Updating Word/Excel File

24. Functions of a Computer
Processing from storage to I/O
e.g. Printing a Word/Excel File

25. Anatomy of Computer: Block Diagram

26. Anatomy of Computer: Detailed Block Diagram

27. Anatomy of Computer: Detailed Block Diagram

28. Anatomy of Computer: Detailed Block Diagram
Processor (CPU)
Common Bus (address, data & control)
Control Unit
Datapath
Arithmetic Logic Unit (ALU)
Registers
Memory
Program Storage
Data Storage
Output Units
Input Units

29. Anatomy of Computer: CPU
Decodes and monitors the execution of instructions.
Controls flow of information in CPU, memory, I/O devices:
System clock (Intel® Core™ I7-720QM Processor (1.6GHz, turbo up to 2.8GHz, 6MB L3 Cache))
Maintains a register called program counter(PC)
Control Unit
Datapath
Arithmetic Logic Unit (ALU)
Registers
Processor (CPU)

30. Anatomy of Computer: CPU
Control Unit
Datapath
Arithmetic Logic Unit (ALU)
Registers
ALU – Performs all arithmetic computations & logic evaluations.
Registers – Storage location in CPU, used to hold data or a memory address during the execution of an instruction..
Processor (CPU)

31. Anatomy of Computer: Common Bus
Common Bus (address, data & control)
A group of conducting wires that allow signals to travel from one point to another:
Address bus – The location of data in memory or I/O devices.
Data bus – Carry data in & out from CPU.
Control bus – Control the operation of the CPU.

32. Anatomy of Computer: Memory
RAM
Volatile – Cannot retain data without power.
Allows the processor to read from & write into any location on memory chip.
ROM
Nonvolatile – When power is removed, the reapplied, the original data will still be there.
Can only be read, cannot be written to or by the processor.