ReactOS achieves x86_64 application support on ARM64

Developer Ahmed Arif has achieved a significant milestone for ReactOS, an open-source operating system aiming for Windows binary compatibility, by enabling it to run x86_64 applications on ARM64 architecture. This was accomplished by integrating the FEX emulator, a user-space emulator used in the Linux ecosystem, into an experimental version of the OS.

The technical implementation utilizes FEX as a real-time translator to convert traditional PC instructions for ARM hardware, such as Raspberry Pi. To ensure the translated code can interact with native system libraries, Arif developed a hybrid runtime called 'dintdll'. This runtime implements executable image loading and necessary links to call native functions from x64 code, mirroring technologies like Microsoft’s ARM64EC used in Windows 11.

To demonstrate the functionality, a video was released showing the classic game Super Mario 64 running via this emulation stack. The ReactOS official profile has described the achievement as a “massive milestone.”