Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
INT 21H supports about 100 different functions. A function is recognised by putting the function number in AH register. For illustration if we want to call function number 01 then we place this value in AH register first by employing MOV instruction and after that call INT 21H:
Some significant DOS function calls are:
DOS
Function Call
Purpose
Example
AH = 01H
For reading a single character from keyboardand echo it on monitor. The input value is put inAL register.
To get one character input in a variable in data segment you may include the following in the code segment:
MOV AH,01
INT 21H
MOV X, AL
(Please note that interrupt call will return value in AL which is being transferred to variable of data segment X. X must be byte type).
AH = 02H
This function prints 8 bit data (normally ASCII) that is stored in DL register on the screen.
To print a character let say '?' on the screen we may have to use following set of commands:
MOV AH, 02H;
MOV DL, '?'
AH = 08H
This is an input function for inputting one character. This is same as AH = 01H functions with the only difference that value does not get displayed on the screen.
Same example as 01 can be used only difference in this case would be that theinput character wouldn't get displayed
MOV AH, 08H
AH = 09H
This program outputs a string whose offset is stored in DX register and that is terminated using a $ character. One can print newline, tab character also.
To print a string "hello world" followed by a carriage return (control character) we may have to use the following assembly program segment.
Example of
CR EQU ODH
; ASCII code of carriage return.
DATA SEGMENT
STRING DB 'HELLO WORLD', CR, '$'
DATA ENDS
CODE SEGMENT
:
MOV AX, DATA
MOV DS, AX
MOV AH, 09H
MOV DX, OFFSET STRING
; Store the offset of string in DX register.
AH = 0AH
For input of string up to 255 characters. The stringis stored in a buffer.
Look in the examples given.
AH = 4CH
Return to DOS
Data, information and knowledge - Information System The nature of information can most easily be defined in the context of its relationship to data and knowledge. Bohn (1994)
Describe the types of flip-flops and latches. Flip-flops are of two types as illustrated below: a. Positive edge triggered b. negative edge triggered Latches are
What are the "field" and "chain" Statements? The FIELD and CHAIN flow logic statements let you Program your own checks. FIELD and CHAIN tell the system which fields you are ch
Q. Show the layout of Dvorak-Dealey keyboard? This was one keyboard layout designed to be a challenger to QWERTY layout. This was designed by August Dvorak and William Dealey a
luminous jewels polishing game
describe briefly about the c token with suitable example program
What is a Priority Interrupt? Ans: A priority interrupt is a type of interrupt that establishes a priority over the many sources to determine which condition is to be serviced
When producing a datapool, you state the kinds of data (called data types) that the script will send for example, customer names, addresses, and unique order numbers or product nam
Distinguish between combinational logic circuits and sequential logic circuits. Ans: Combinational logic circuits:- (i) Outputs only depend upon present state of the i
Compare the use of switch statement with the use of nested if-else statement. If-else statement: When there are many conditional statements that may all evaluate to true, bu
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd