Interrupt vector table
 | This article needs attention from an expert on the subject. Please add a reason or a talk parameter to this template to explain the issue with the article. |
The interrupt descriptor table (IDT) associates each interrupt or exception identifier with a descriptor for the instructions that service the associated event. Like the GDT and LDTs, the IDT is an array of 8-byte descriptors. Unlike the GDT and LDTs, the first entry of the IDT may contain a descriptor. To form an index into the IDT, the processor multiplies the interrupt or exception identifier by eight. Because there are only 256 identifiers, the IDT need not contain more than 256 descriptors. It can contain fewer than 256 entries; entries are required only for interrupt identifiers that are actually used.
Note that the IDT may reside anywhere in physical memory. The linear address for the base of the IDT is contained in the IDT register.
External links
Intel® Architecture Software Developer's Manual, Volume 3: System Programming Guide