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WFI

Wait for Interrupt.

Syntax

WFI{cond}

where:

cond

is an optional condition code.

Usage

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 executes as a NOP instruction in ARMv6T2.

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.

Architectures

This ARM instruction is available in ARMv6K and above.

This 32-bit Thumb instruction is available in ARMv6T2 and above.

This 16-bit Thumb instruction is available in ARMv6T2 and above.

See also