Slide 1 of 53 Ver. 1.0 Programming in C ASSEMBLY LANGUAGE LECTURE 01-05 BASIC INFORMATION By SHERY...

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Programming in C

ASSEMBLY LANGUAGE

LECTURE 01-05

BASIC INFORMATION

By

SHERY KHAN

10:00 to 11:30

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Programming in C

In this session, you will learn to:Identify the benefits and features of Assembly language

What is Assembler

How to use Assembler

Identify the structure of Assembly functions

Binary And Hexadecimal Discussion

Short History of Assembly language(iApx88 Hierarchy)

Detail Registers and Categories of Register

Register Functionalities

Sample Program

Data Declaration

Sample Program

………………………….

Objectives

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What is Assembly Language

Assembly Language is a Machine Specific Programming Language with one to one Correspondence b/w its Statement and computer native Machine Language

There are many Different Types of Assembly Language each specific to processor or processor Family this is because the instruction in Assembly language are Designed to match a Computer Machine Instructions Set and Hardware Architecture

IBM PC assembly Language refer to instruction recognized by num of Different micro processors in Intel family

8086,8088,80186,80386,80486, and Pentium

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AssemblerAssembler is a program that Convert source code program from

Assemble Language into Machine Language

The Assembler can optionally generate a source listing file with line number ,memory addresses ,source data code statement ,and cross reference listing of Symbol and variable used in program

Linker

A companion program called linker combine individual files created bt assembler with Single Executable File: DEBUGGER:

Third Program called Debugger provides away for programmer to trace execution of program and Examine the Content of memory

What is Assembler ? & TOOLS ?

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Steps for Understanding to develop a Context:

Step 1:

Write a program name with ex01.asm Save it in the Assemble folder in let example D’derive

Step 2: then go to the Run write “cmd “ a Dos is Open

Following command is on Dos you will See

C:\document setting \window Xp >

Now write the in the front of this Command “d;”

SEE THE Detail with synapshots:

How to use Assembler ? & TOOLS ?

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First Look Simple Dos is Open


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I can Give him a Directory Were I Save the Assembly Folder Like D drive in Second Pic I can write cd which mean Display Change in Directory and Give Him A Folder Name”

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Now write the Command “nasm ex01.asm-o ex01.com-l ex01.lst after this Execution a Lst and COM File is Generated Here Pictorial View

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Now Edit command is used to Write Some Instruction or rewrite the File

So for this purpose we use “Edit ex01.asm “

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For Execution of COM file we Must Load it in the Debugger the Last Step is And Command is

afd Ex01.COM

Pictorial View Here

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Identify the structure of Assembly functions :

Why we Learn Assembly Language???

If our Software want to direct communication with the Pc OS may be Necessary or Computer Game

Application might have to directly Access the Video Controller or Sound Card So in Assembly Language a routine is Written for Speedy Communication with

Hardware.like Utility Softwares

Why It is Called Low level Language ??

Because it is Close to Machine Language.

Weakness that its programs are not recompiled & Executed on different Computer.

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Number System Disscussion

System Base Possible Digits

Binary 2 0,1

octal 8 0,1,2,3,4,5,6,7

Decimal 10 0-9

Hexa Decimal

16 0-9 A,B,C,D,E,F

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Assembly Debugger work with Hexadecimal System which take 4 bits

Decimal To Binary to Hexdecimal

Here Example

Decimal Binary Hexa Decimal

65 0100 0001 41

41

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Convert 3BA4 to Decimal

3*16 pow 3 +

B*16 pow 2 +

A*16 pow 1 +

4*16 pow 0 +

Decimal Result is 15268

Above A=10 B=11

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Signed Number:

A Signed Byte Used Only 7 Bits were 0 indicate +ve and 1 indicate –ve

Unsigned Number:

A Unsigned Byte used 8 bits largest value is 255

Bit: Each Digit in a Binary Num System Is Bit

Byte: Eight Bits together Make A byte

Word: 16 Bits Are called Word which is 2 byte long

Double Word: 32 bits are called DW

Quad Word : 64 bits Are called QW

Calculation Formula: (2 pow b -1) b indicate bits.


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CPU DESIGN SIMPLIFIED VIEW

Data BUS

Address Register

Address BUS

Data RegisterMemory

Cpu

ALU

CPU:

FETCH

DECODE

Execute

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Adress ,Data And Control Bus:

Adress Bus:is a Uni directional Bus and Adress Always travel from Processor to Memory because memory cannot predict which element processor at a particular time need.

Processor Memory

Data Bus:

Data Moves from processor to memory and Memory to Processor So Data Bus is

Bi directional

Memory To Processor (Read operation)

Processor to Memory (Write operation)

Control Bus :Also Bi directional

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REGISTERs:

Register:

with in A CPU A high Speed Storage area is Called

Register which are directly linked to a control unit

Basic Purpose is to store operand in Arthematic Calculations

They are Like a Scratch pad Ram inside a Processor like Ram.

They Are Named as A,B,C,D .

USED:

When we need more than one data element inside the processor at one time.

……..

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REGISTER CATEGORIES iApx88

REGISTERS/IApx88

General Purpose Index Registers Status Control Flag Register Segment

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REGISTER CATEGORIES iApx88 / General Register

GENERAL REGISTER

AX BX CX DX

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INDEX REGISTER

INDEX REGISTER

BP SP SI DI

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Status Control Register

Status Control REGISTER

IP

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FLAG REGISTER

Flag REGISTER

DF IF CF OF

Control FLagStatus Flag

TF SF ZF

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SEGMENT REGISTER

SEGMENT REGISTER

CS DS SS ES

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Accumulator Register: Central Register

All Mathematical And Logical operation are Performed on it.

Word size of processor is defined by Accumulator .

Index Register : Hold Address not Data .

Flag Register: it is Meaning Less As Whole .Individual Bit carry different Meaning it is of 8 bit ,16,32bit like Accumulator But as unit it is Meaning Less commonly Carry Flag is Used

16 bit num + 16 bit Accumulator=17 the 17 bit is placed as carry without this No Meaning

REGISTER: MAIN POINTS

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REGISTER: MAIN POINTS

Program Counter or Instruction Pointer:

Every thing Must be Translated into Binary for our Processor to

understand & order of Instruction is controlled by this Register.

INSTRUCTION GROUP:

Data Movement Instruction

Mov ax,bx

Lad 123456

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Instruction Group Continue

ALU INSTRUCTION:

Logical OR

Logical And

Logical XOR

and ax,1345

and bx ,0534

Add bx,[1200]

Data placed at1200

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Instruction Group ContinueProgram Control Instruction

Instruction pointer points to next instruction and instruction run one after other with the help of this

register

I.E Flow Control

Cmp ax,0

Jne 12345

SPECIAL INSTRUCTION:

Change the behaviour of Processor

Cli

sti

Changing theFlow of

instructions

Clear the intrupt flag & SET IT

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GENERAL REGISTER:

AX,BX ,CX and DX are General Purpose Register

“X” in there name Stand For Extended meaning 16 bit.

AX mean we are referring to 16 bit “A “ Register.

UPPER & LOWER BYTE:

are Separately Available as AH( A high Byte)

AL(A low BYTE)

All General Purpose Register can be Accessed as 16 bit register or as two 8 bit register

AX::: ACCUMULATOR

BX::: BASE (role in Memory Addressing)

CX::: Counter (work with automatic Count)

DX::DESTINATION ( act as destination in I/O)

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INDEX REGISTER:

SI are Stand for Source INDEXDI stand for Destination INDEXINDEX REGISTER HOLD ADDRESSIntel Allow MATHEMATICAL & LOGICAL OPERATIONSSTRING INSTRUCTION: A SPECIAL CLASS of Instruction is Called String instructionSI and DI are 16bit and cannot be used as 8 bit register pairIP:(Instruction Pointer):contain the Adress of Next Instruction to be Executed NO Memory Access or Mathematic is Done SP(Stack pointer)::Memory pointer and is Used indirectly by set of instructionsBP(base pointer):: Memory pointer contain the adress in the Special Area of memory called STack

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FLAG REGISTER is Not Meaning Full As a Whole But it was Bitwise significant .

CARRY FLAG: when two 16 bit num are added the answer is 17 bit long the extra bit which could not Fit in the target register is placed in the carry flag

PARITY FLAG::odd or even one bit only: this flag is used to verify the integrity of data.

Auxiliary Carry : during operation if a carry goes from one nibble to another is called Auxiliary FLAG

Zero FLAG: if the last logical instruction or mathematical instruction produced zero the zero flag is set:

Sign Flag:

-ve number is represented as 1 +ve num it is zero

Trap Flag:special role in debugging

Intrupt Flag: interruption of processor is disable or enable by making this bit zero or one

Direction Flag: specially related , this flag tells wheather the current operation has to be done

FLAG REGISTER:

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SEGMENT REGISTER:

The

CS (code segment register)

DS(Data Segment Register)

SS(Stack Segment)

ES(Extra Segment Register)

…………………

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SAMPLE PROGRAM

Org[0x0100]mov ax,5add ax,bxmov bx,15add ax,bx

mov ax,0x4c00Int 0x21

Slide 1 of 53 Ver. 1.0 Programming in C ASSEMBLY LANGUAGE LECTURE 01-05 BASIC INFORMATION By SHERY...

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