Windows on Arm can mix native Arm and emulated x64 code in one app

Windows on Arm can run native Arm and emulated x64 code in one app process using a Microsoft technology called Arm64EC.

It matters for apps that rely on older components, such as Office add-ins and audio plugins, which may not yet be available in Arm versions.

Before Arm64EC, porting an app to Arm could require all the code and components loaded into it to be converted together.

Arm64EC code runs as Arm instructions but follows some x64 software rules, allowing it to work alongside x64 code.

This can make it easier to move an app to Arm gradually, though Arm64EC has some performance and compatibility trade-offs.

Windows can also use native Arm code in parts of the system when working with an x64 app.

The technology supports x64 code, while older 32-bit x86 apps continue to use a separate emulation layer.