SoftwareInterrupt vectors points to consecutive locations in the very first block of the addressable space. Each vector takes two consecutive addresses; thus INT_00 points to 0x00000, INT_01 points to 0x00002 and so on. INT_FF points to 0x001fe.
For servicing an interrupt, the CPU will do nothing but a fetch bus cycle toward the corresponding address. What is expected to be there is a branch instruction to the actual ISR.
INT_00 is the computer's clock tick, raised at 1 ms intervals. A multitasking operating system can make use of INT_0 to define processes (or threads) time-slices.
INT_01 through INT_FF are used by the CPU to generate exceptions. Software code is allowed to raise interrupts within this range by using the INT instruction.
All interrupts are maskable. Not masked interrupts can be served in a nested fashion according to interrupt priority.
Queuing interrupt requests is the job of the Operating System. The CPU limits itself to service interrupts in the simple way we just described.
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