11.70 NOP

No Operation.

Syntax

NOP{cond}

where:

cond

is an optional condition code.

Usage

NOP does nothing. If NOP is not implemented as a specific instruction on your target architecture, the assembler treats it as a pseudo-instruction and generates an alternative instruction that does nothing, such as MOV r0, r0 (ARM) or MOV r8, r8 (Thumb).

NOP is not necessarily a time-consuming NOP. The processor might remove it from the pipeline before it reaches the execution stage.

You can use NOP for padding, for example to place the following instruction on a 64-bit boundary in ARM, or a 32-bit boundary in Thumb.

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.

NOP is available on all other ARM and Thumb architectures as a pseudo-instruction.

Non-ConfidentialPDF file icon PDF versionARM DUI0473M
Copyright © 2010-2016 ARM Limited or its affiliates. All rights reserved.