WFI Wait for interrupt This instruction is a hint instruction that indicates that the PE can enter a low-power state and remain there until a wakeup event occurs. For more information, see Wait For Interrupt. As described in Wait For Interrupt, the execution of a WFI instruction that would otherwise cause entry to a low-power state can be trapped to a higher Exception level. 1 1 0 1 0 1 0 1 0 0 0 0 0 0 1 1 0 0 1 0 0 0 0 0 0 1 1 1 1 1 1 1 WFI // Empty. constant integer localtimeout = 1 << 64; // No local timeout event is generated Hint_WFI(localtimeout, WFxType_WFI);