Arm C Language Extensions

This repository contains the source material from which the specifications for the Arm C Language Extensions (ACLE) are derived.

Browse the current specifications on the ACLE website.

Versioning

Arm no longer publishes quarterly specification releases. We publish the current specification after each reviewed change merges into branch main. This process gives users earlier access to new features, clarifications, and corrections.

The PDF version of the documents can be retrieved from the releases page.

Branch main contains the current ACLE specification and ongoing development.

Legacy releases

The releases page also contains the legacy quarterly releases through 2026Q1.

Pre-GitHub versions of the documents were previously released on Arm Developer, and are also hosted in this repository, in Legacy releases.

Contributing

Contributions of any kind are always welcome! Please check the contribution guidelines for details.

Defect reports

Please report defects in or enhancements to the specifications in this folder to the issue tracker page on GitHub.

For reporting defects or enhancements to documents that currently are not yet included in this repo and are thus only hosted on developer.arm.com, please send an email to arm.acle@arm.com.

List of documents

Arm C Language Extensions

Morello Supplement to the Arm C Language Extensions

Arm MVE Intrinsics

Arm Neon Intrinsics Reference

Arm®v8-M Security Extensions - Requirements on Development Tools

The PDF versions can be found in the latest GitHub release.

License

All the open-source ACLE documents are licensed under the Creative Commons Attribution-ShareAlike 4.0 International License + grant of Patent License.

The closed-source legacy ACLE releases are licensed under an Arm proprietary license.

For more information see LICENSE.

Past contributors

The list below represents the list of people that have been contributing since July 2021, when the ACLE specifications were released with an open source license.

However, the ACLE is a collective project that was started few years ago, and that since then has seen the contribution of many people before it was released as an open source project.

Contributors ✨

Thanks goes to these wonderful people (emoji key):

This project follows the all-contributors specification. Contributions of any kind welcome!