Setting Up

A program initializes for ULI in the following major steps:

Open the device special file for the device.
For a VME device, map the device addresses into process memory (see "Mapping a VME Device Into Process Address Space".
Lock the program address space in memory.
Initialize any data structures used by the interrupt handler.
Register the interrupt handler.
Interact with the device and the interrupt handler.

Any time after the handler has been registered, an interrupt can occur, causing entry to the ULI handler.