Introduction

ARM64EC and ARM64X are two technologies critical for Windows on Arm. This document gathers useful links and articles about both.

• Arm64X is a new type of binary that can contain both the classic Arm64 code and Arm64EC code together. This makes Arm64x compatible for both the classic Arm64 and Arm64EC processes on a Windows on Arm device and a particularly good fit for middleware or plugins that may be used by both ABIs. To build Arm64X binaries, see Build Arm64X Binaries.

• Arm64EC (“Emulation Compatible”) enables you to build new native apps or incrementally. Arm64EC is a new application binary interface (ABI) for apps running on Arm devices with Windows 11. It is a Windows 11 feature that requires the use of the Windows 11 SDK and is not available on Windows 10 on Arm.

Resources

• https://learn.microsoft.com/en-us/windows/arm/arm64x-pe

• Understanding Arm64EC ABI and assembly code

• http://www.emulators.com/docs/abc_arm64ec_explained.htm

• Porting applications to Arm64 using Arm64EC video: