#Meaning of codes in emu8086 code#

#Meaning of codes in emu8086 code#

The above two line code is used to exit to dos or exit to operating system. It works with the value of AH register, If the Value is 9 or 9h or 9H (all means the same), That means PRINT the string whos Address is Loaded in DX register. Standard Input and Standard Output related Interupts are found in INT 21H which is also called as DOS interrupt. To do input and output in Assembly Language we use Interrupts. LEA stands for Load Effective Address which is used to assign Address of variable to DX register (The same can be written like this also MOV DX,OFFSET MESSAGE both mean the same). The above three line code is used to print the string inside the MESSAGE variable. Other Segments are not needed to be initialized, Only assuming is enhalf. This part is also called INITIALIZATION OF DATA SEGMENT and It is important so that the Data elements or variables in the DATA Segment are made accessable. AX is the first and most important register in the ALU unit. But we cannot move DATA Directly to DS due to MOV commands restriction, Hence we move DATA to AX and then from AX to DS. MOV is a keyword to move the second element into the first element. : is used to define a label as in C programming.ДЄfter Assuming DATA and CODE Segment, Still it is compulsory to initialize Data Segment to DS register. START is the label used to show the starting point of the code which is written in the Code Segment. In this Assembly Language Programming, their are Different Registers present for Different Purpose So we have to assume DATA is the name given to Data Segment register and CODE is the name given to Code Segment register (SS,ES are used in the same way as CS,DS ) We can write just ENDS But to differentiate the end of which segment it is of which we have to write the same name given to the Data Segment.Д¬ODE SEGMENT is the starting point of the Code Segment in a Program and CODE is the name given to this segment and SEGMENT is the keyword for defining Segments, Where we can write the coding of the program. $ is used as NULL character in C programming, So that compiler can understand where to STOP.ДATA ENDS is the End point of the Data Segment in a Program. Character need One Byte so to store Character or String we need DB only that donвЂ™t mean DB canвЂ™t hold number or numerical value.

In Assembly language programs, variables are defined by Data Size not its Type. DB stands for Define Byte and is of One byte (8 bits). MESSAGE is the variable name given to a Data Type (Size) that is DB. Code Segment and Data Segment.ДATA SEGMENT is the starting point of the Data Segment in a Program and DATA is the name given to this segment and SEGMENT is the keyword for defining Segments, Where we can declare our variables. Code Segment if at all you donвЂ™t need variable(s) for your program.if you need variable(s) for your program you will need two Segments i.e. In this Assembly Language Programming, A single program is divided into four Segments which are 1. START : MOV AX, DATA MOV DS, AX LEA DX ,MESSAGE MESSAGE DB 'HELLO WORLD!!!$' ENDS CODE SEGMENT ASSUME DS : DATA CS : CODE