0 = Only enabled interrupts or events can wakeup the processor, disabled interrupts are excluded.
1 = Enabled events and all interrupts, including disabled interrupts, can wakeup the processor.
When an event or interrupt becomes pending, the event signal wakes up the processor from WFE. If the
processor is not waiting for an event, the event is registered and affects the next WFE.
The processor also wakes up on execution of an SEV instruction or an external event.
struct SEVONPEND_R { /* private fields */ }