Contribution Guidelines

Thank you for considering contributing!

Contributions are always welcome. We accept bug fixes, proposals and new ideas, or simply editorial improvements.

By submitting a pull request you are implicitly adhering to the contribution agreement


You can report a bug by creating an issue. You can also fix it yourself with a pull request.

Proposals for new content

We are open to any proposal, including the introduction of new sets of intrinsics.

To add new intrinsics or preprocessor macros, Arm recommends that you present them in a pull request, along with the following details:

  1. A rationale in support of these intrinsics or macros.
  2. A design document to keep track of the reasoning that made the proposal reach its current state.

Please note that this extra information is not a requirement for submitting new content. Contributors are trusted to use their judgment to decide whether or not the proposal needs this information. Arm recommends that you add this information so that it is easier for new ideas to be discussed and possibly accepted, especially for changes of great impact.

Editorial improvements

To check the outcome of your changes, run the script (requires docker). The scripts generate the PDFs of the specifications and stores them in the folder pdfs.

Continuous integration

The continuous integration bot executes the script:


PDFs are generated automatically in response to a pull request. You can download the PDFs in the Actions tab of any pull request.

An additional step uses markdown-link-check` to check that all the links in the markdown files are resolving correcly.

Branches and pull requests.

The branch latest-release is the release branch, which contains the code used to build the PDFs of the latest official release. The branch latest-release is also used to build the website of the ACLE project.

New development (bug-fixes, proposals, extensions, and so on) is committed on the main branch. Therefore, please submit your PR against the branch main.

It is good practice to track changes. In the section Changes for next release, please list any changes that you have made to the document. For an example, see this PR.

Contribution agreement

Contributions to this project are licensed under an inbound=outbound model such that any such contributions are licensed by the contributor under the same terms as those in the LICENSE file.

We do not require copyright assignment. The original contributor will retain the copyright.

All contributors

This project follows the allcontributors guidelines. We assume that contributors are happy to be added to the list of contributors in the main README file. Please let us know explicitly if that is not the case in the PR or in the issue you have raised.