Index

WFIT

Wait For Interrupt with Timeout is a hint instruction that indicates that the PE can enter a low-power state and remain there until either a local timeout event or a wakeup event occurs. For more information, see Wait For Interrupt.

As described in Wait For Interrupt, the execution of a WFIT instruction that would otherwise cause entry to a low-power state can be trapped to a higher Exception level.

System
(FEAT_WFxT)

31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
1 1 0 1 0 1 0 1 0 0 0 0 0 0 1 1 0 0 0 1 0 0 0 0 0 0 1 Rd

WFIT <Xt>

if !IsFeatureImplemented(FEAT_WFxT) then UNDEFINED;

integer d = UInt(Rd);

Assembler Symbols

<Xt>

Is the 64-bit name of the general-purpose source register, encoded in the "Rd" field.

Operation

integer localtimeout = UInt(X[d, 64]);

if Halted() && ConstrainUnpredictableBool(Unpredictable_WFxTDEBUG) then
    EndOfInstruction();

Hint_WFI(localtimeout, WFxType_WFIT);