These routines are used to move the cursor, change the color of the characters that are displayed, change the character size, print strings of text and many other display functions. Other sub-routines control every piece of hardware attached to the system. The sub-routines used in the operating system require many 8088 instructions to preform a specificate task and are very complex in there program style. The 8088 was designed with a special instruction called INT that will execute any one of these sub-routines from within our program. To use a software interrupt, the programmer must set-up the program before the INT instruction is actually executed.
Most interrupts require certain values for the proper operation of the interrupt sub-routine.
In other words, all interrupts require an input from your program and it must be stored inside specific registers. In order to use these interrupts you must make reference to the interrupt list that is supplied by IBM and Micro-Soft. It is not practical to rewrite this list in this book because of the size of it's contents. I would recommend that you purchase a book that contains some of the more common interrupts. This book will, however, list some of the most used interrupts in programming.