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
Normal 0 false false false EN-US X-NONE X-NONE
Q. Device drivers in Windows system? In Windows system device drivers are implemented as dynamic link libraries (DLLs). This scheme has advantages which DLLs comprises sharea
Data phases: After the address phase (particularly, starting with the cycle that DEVSEL# goes low) comes a burst of one or more data phases. In all the cases, initiator drives
Consider the Hire Assistant problem. We interview n candidates and always hire the best qualified so far. Let n = 5 for our example. Find the probabilities that we hire exactly 1 t
Q. Explain Design of adder? Adders play one of the most significant roles in binary arithmetic. As a matter of fact fixed point addition is frequently used as a simple measure
What is User Defined Functions? User-Defined Functions permit defining its own T-SQL functions that can accept 0 or more parameters and return a single scalar data value or a t
Compare zero-, one, two-, and three- address machines by writing programs to compute X = (A + B x C)/(D - E x F) for every of the four machines. Do n
Q. How to Add Cell Padding? As you can see, text is too close to the edges of the cells. You will add padding to the cells to leave room between text and cells. 1. Click in
how to find the type of cohesion in a module
Q. Instruction of a micro-program? A micro-instruction is an instruction of a micro-program. It specifies one or more than one micro-operations that can be executed concurrentl
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