ARM64EC amps up Windows 11 on ARM app development


If you’re all in on Windows 11, then there is some good news heading your way. Microsoft has just announced ARM64EC, which promises to be a major boost for Windows 11 on ARM apps.

Or, rather, application development for this new platform.

You can glean at all the technical details here in this announcement post that details the technology.

It is basically designed to give developers the freedom to mix and match different types of code for Windows 11 on ARM applications. The technology allows them to switch part of the codebase of an app to run on the ARM architecture natively, while other parts of the app run in emulation.

In other words, if you are coder, then you can make software for Windows 11 on ARM, even if your application has dependencies that run on x64.

Microsoft talks about how traditionally, rebuilding an application for ARM has meant recompiling the entire application. While this is a great experience for the customer, for developers, porting the app boils down to an all-or-nothing experience.

ARM64EC changes that:

“With ARM64EC, you can choose to start small and build incrementally. You can identify a part of your codebase that would benefit most from native performance and rebuild it as ARM64EC. The rest of the app will remain fully functional as emulated x64, but the recompiled ARM64EC parts will now have native speed.  Over time, you can recompile more of the app as ARM64EC to further improve performance and conserve battery life for your app’s customers.”

With ARM64EC, developers have the choice of picking the most important parts of their apps to switch over to native ARM performance. They then retain the liberty to migrate the rest over, as they have more time or as dependencies gain support for the ARM platform.

Microsoft has already rebuilt the binaries of Windows 11 on ARM with the technology, and it allows system code loaded by x64 to run with native speed.

The Office team also used ARM64EC for the upcoming 64-bit Office for ARM.

Developers that want to start working on this can download the latest Windows Insider SDK and Visual Studio Preview to get going. Microsoft has also compiled this doc that has steps to help add the ARM64EC configuration.