WFIT

Wait for interrupt with timeout

This instruction provides a hint 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 class

(FEAT_WFxT)

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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
																				CRm				op2

Encoding

WFIT <Xt>

Decode

if !IsFeatureImplemented(FEAT_WFxT) then EndOfDecode(Decode_UNDEF); constant integer d = UInt(Rd);

Assembler Symbols

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

Operation

constant integer localtimeout = UInt(X[d, 64]); if Halted() && ConstrainUnpredictableBool(Unpredictable_WFxTDEBUG) then ExecuteAsNOP(); Hint_WFIT(localtimeout);

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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
																				CRm				op2

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
																				CRm				op2