At the end of last year, Neowin reported that Microsoft was working on the introduction of 64-bit emulation for PCs with an ARM chip running Windows 10. A recent GitHub commit from March this year, spotted by Longhorn on Twitter, who is part of the checkra1n jailbreak team, suggests that Microsoft has made progress towards this goal.
As of now, Windows 10 ARM PCs can emulate 32-bit Windows applications, thanks to the Windows on Windows abstraction layer. With this addition, users may finally be able to run full 64-bit versions of Windows applications, such as Adobe Premiere Pro, in emulation.
The commit was written by Kenny Kerr, a software engineer on the Windows team, and it says “Add linker support for x64 code emulation on ARM64” This is good news for people eager to use 64-bit Windows applications on ARM PCs.
Of course, you can run 64-bit ARM applications (ARM64) natively, and if a developer recompiled their application as an ARM64 application it would work. Of course, this requires extra effort to recompile for Windows 10 on ARM. And, that could be a real headache for a sprawling application like Adobe’s.
With x64 emulation, any 64-bit Windows application will simply be able to run as is from the emulator.
Speaking of x64 emulation, Erin Chapple, CEO of Windows, told ZDNet: “Emulating x64 in addition to x86 doubles the engineering work. Unlike 32-bit support, this would also be a new job. In addition, Windows only supports the Windows on Windows Abstraction Layer (WOW) for 32-bit applications, not 64-bit applications. We should add support for a Windows layer on Windows 64 bitIn 2018.
x86_64 on Arm64 machine type.
—Longhorn (@never_released) May 17, 2020
Performance is key
So why hasn’t this been done before now? Well, this has to do with performance issues, because using emulation is trickier to run x64 applications without problems than 32-bit emulation. And of course, the good news is that as Windows 10 on ARM has become more and more powerful, now using Qualcomm’s Snapdragon 8cx chips, any performance problem is likely to be felt much less in terms of emulation. 64 bit.
It will be interesting to see if the Redmond-based giant manages to bridge the performance gap to offer the user an experience comparable to that of Intel devices. However, support probably won’t be added until the second half of 2021.