Function 25h Set Interrupt Vector

mov dx, seg InterruptHandler

mov ds, dx

mov dx, offset InterruptHandler ;ds:dx points to new handler

mov al, InterruptNumber ;interrupt vector

mov ah, 25h ;Set Interrupt Vector

int 21h

Set Interrupt Vector (Function 25h) replaces the vector-table entry with the address of the specified interrupt handler.

Parameters

InterruptHandler

Specifies the address of the new interrupt handler.

InterruptNumber

Specifies the number of the interrupt (00h-0FFh) that is to cause the specified handler to be called.

Return Value

This function has no return value.

Comments

Programs should never set an interrupt vector directly in memory. Programs should use this function to replace an interrupt vector.

When a program installs a new interrupt handler, it should use Get Interrupt Vector (Function 35h) to retrieve the address of the original interrupt handler and restore this original address before terminating.

See Also

Function 35h Get Interrupt Vector