3.12.6. ISB

Instruction Synchronization Barrier.

Syntax

ISB{cond} {opt}

Where:

cond

Is an optional condition code. See Conditional execution.

opt

Specifies an optional limitation on the ISB operation. Values are:

SY

Fully system ISB operation, encoded as opt == '1111'. Can be omitted.

All other encodings of opt are reserved. The corresponding instructions execute as full system ISB operations, but software must not rely on this behavior.

Operation

ISB acts as an instruction synchronization barrier. It flushes the pipeline of the processor, so that all instructions following the ISB are fetched from cache or memory again, after the ISB instruction has been completed.

Condition flags

This instruction does not change the flags.

Examples

    ISB  ; Instruction Synchronisation Barrier 

Copyright © 2015, 2018 Arm. All rights reserved.ARM DUI 0646C
Non-ConfidentialID121118