Important Notice

The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.

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  Address
  (hex)       Size   Description
 
  0000:0000   1K     A series of double-word addresses that form the
   through           interrupt vector table. These addresses occur
  0000:03FF          at multiples of 4 bytes (0000h, 0004h,
                     0008h...). Addresses in the table correspond
                     sequentially with software interrupts──0000h
                     with interrupt 00h, 0004h with interrupt 01h,
                     etc.
 
                     Not all addresses in the table point to
                     interrupt service routines. Some point to areas
                     of nonexecutable data. Other addresses are
                     null, indicating the interrupt is not used. Do
                     not call interrupts that do not have table
                     entries that point to valid interrupt routines.
 
                     Always disable interrupts with CLI before
                     changing the contents of these locations.
                     Reenable interrupts with STI. The Set Interrupt
                     Vector and Get Interrupt Vector DOS functions
                     automate this task.
 
  See also: Set Interrupt Vector, Get Interrupt Vector,
            DOS Segment Map, INT, IRET
                                    -♦-