13.201 WFI

Wait for Interrupt.





is an optional condition code.


This is a hint instruction. It is optional whether this instruction is implemented or not. If this instruction is not implemented, it executes as a NOP. The assembler produces a diagnostic message if the instruction executes as a NOP on the target.

WFI suspends execution until one of the following events occurs:

  • An IRQ interrupt, regardless of the CPSR I-bit.
  • An FIQ interrupt, regardless of the CPSR F-bit.
  • An Imprecise Data abort, unless masked by the CPSR A-bit.
  • A Debug Entry request, regardless of whether Debug is enabled.


This instruction is available in A32 and T32.

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