WFE -- AArch32

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WFE

Wait For Event is a hint instruction that indicates that the PE can enter a low-power state and remain there until a wakeup event occurs. Wakeup events include the event signaled as a result of executing the SEV instruction on any PE in the multiprocessor system. For more information, see Wait For Event and Send Event.

As described in Wait For Event and Send Event, the execution of a WFE instruction that would otherwise cause entry to a low-power state can be trapped to a higher Exception level, see HCR.TWE, SCR.TWE, and SCTLR.nTWE.

It has encodings from the following instruction sets: A32 ( A1 ) and T32 ( T1 and T2 ) .

Decode for this encoding

Assembler Symbols

15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
1	0	1	1	1	1	1	1	0	0	1	0	0	0	0	0
		hint

Operation

if ConditionPassed() then EncodingSpecificOperations(); if IsEventRegisterSet() then ClearEventRegister(); else if HaveEL(EL3) && EL3SDDUndefPriority() then // Check for traps described by the Secure Monitor. // If the trap is enabled, the instruction will be UNDEFINED because EDSCR.SDD is 1. AArch32_CheckForWFxTrap(EL3, WFxType_WFE); end; if PSTATE.EL == EL0 then // Check for traps described by the OS. AArch32_CheckForWFxTrap(EL1, WFxType_WFE); end; if PSTATE.EL IN {EL0, EL1} && EL2Enabled() && !IsInHost() then // Check for traps described by the Hypervisor. AArch32_CheckForWFxTrap(EL2, WFxType_WFE); end; if HaveEL(EL3) && PSTATE.M != M32_Monitor then // Check for traps described by the Secure Monitor. AArch32_CheckForWFxTrap(EL3, WFxType_WFE); end; WaitForEvent(); end; end;

2026-03_rel 2026-03-26 20:48:11

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
!= 1111				0	0	1	1	0	0	1	0	0	0	0	0	(1)	(1)	(1)	(1)	(0)	(0)	(0)	(0)	0	0	0	0	0	0	1	0
cond									R			imm4								imm12

15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
1	1	1	1	0	0	1	1	1	0	1	0	(1)	(1)	(1)	(1)	1	0	(0)	0	(0)	0	0	0	0	0	0	0	0	0	1	0
																								hint				option