back to article The three or so people who run Windows 10 on Arm might be glad to know that x64 emulation is in preview

Microsoft has finally released a preview of 64-bit Intel emulation for Windows 10 on Arm in its latest Dev Channel Insider build. It has been a while coming, and did not make it in November as previously promised. It is, however, at last here for Dev Channel Windows Insiders running on Arm hardware. Microsoft would dearly …

  1. alain williams Silver badge

    Better to port ?

    Would it not be better to put effort into making it easier to port programs between x64 and ARM and set up multiple repositories for different architectures ?

    I have been porting *nix programs between CPU types for over 35 years, it takes a bit of care but is not really hard.

    1. Sandtitz Silver badge

      Re: Better to port ?

      "Would it not be better to put effort into making it easier to port programs between x64 and ARM and set up multiple repositories for different architectures ?"

      Of course it would.

      Chicken and egg - because these Windows-on-ARM computers/users are a tiny niche the software companies can't be arsed; on the other end the freeware coders can't afford one of those units to test their software just for a handful of users.

      1. needmorehare
        Devil

        Most software won’t be ported

        Like video games and niche industrial automation software. Here’s the big rub, if Windows 10 ARM does not end up maintaining full backwards compatibility, then it won’t have a lot of uptake from IT professionals, meaning businesses won’t use it.

        Think of it this way. If you knew for sure that x86 was on the way out and that Microsoft was not going to guarantee your old software to work, wouldn’t you take advantage of the opportunity to reassess your choices?

        From an IT professional standpoint, Apple is now offering suits the ability to install their iOS appy apps they love so much on a bigger screen while their stack improves your job security against offshoring (no custom PXE boot restores, no on-site Dell/HP engineers, expensive remote management tools, rapidly changing technologies and very few internationalised error codes.

    2. Def Silver badge

      Re: Better to port ?

      Most of the time you don't even port to ARM. You port to UWP and recompile for ARM.

      And that's what I'm not going to bother doing for my WinAPI applications. At least not yet. I will port them to a cross platform UI (my own) and when I have that up and running (and ported to macOS and Linux), then I will port the thin platform specific layer to UWP.

    3. karlkarl Silver badge

      Re: Better to port ?

      Yep, Microsoft doesn't really want you to port to ARM. They want you to faff about with their silly UWP lockin store and prosumer developer licenses.

      Otherwise they would just provide us with a simple (probably GCC based) cross compiler like any other real systems vendor does.

  2. fnusnu

    Original Surface

    It's a shame there's no Win10 for the original Surface

    1. Phil Kingston

      Re: Original Surface

      I've yet to find a spare afternoon to try it, but https://forum.xda-developers.com/t/windows-10-on-arm-for-surface-rt.3830124/post-82022643

  3. DS999

    Microsoft Office is x64 only?

    Maybe the guys who made the emulator x32 only assumed that Office would be ported to ARM quickly if Microsoft was at all serious about pushing Windows/ARM?

  4. Jason Hindle

    The three or so people

    I guess Apple has vastly more ARM Mac users already, and their product has been on the market for just a month.

    1. katrinab Silver badge

      Re: The three or so people

      And they could potentially be the vast majority of Windows on Arm customers.

      1. Jason Hindle

        Re: The three or so people

        “ And they could potentially be the vast majority of Windows on Arm customers.”

        Given the number experimenting with qemu (and finding Windows runs faster than current native ARM Window on the bare metal on offer...).

  5. dharmOS

    x64 instruction set patent expires this year

    I think AMD patented the x86-64 bit extensions back in 2000, so along with the Intel SSE, SSE2 etc extensions, only expire this year. So till now, MS could only have a x86-32 bit emulator to run legacy Windows programs. Rosetta2 released in 2020 neatly steps around this limitation by precisely only being released this year. Note that Rosetta2 does not support any of the newer Intel extensions such as AVX etc. I guess MS x86-64 bit emulator will follow Apple’s lead in which instructions are emulated.

    1. needmorehare
      Facepalm

      No can do

      Microsoft will be stuck supporting all x86 instructions forever or they will lose their customers. People use PCs running Windows because they get to use a powerful computer which runs everything no matter how old or how new it is. Take away the power and people will still use it but take away the “runs everything” compatibility too and it’s dead.

      Microsoft would do well to partner with Intel to create some kind of “x86 accelerator card” using DMA so that folks can forevermore run their old applications and weird/wonderful userspace system services/daemons at essentially full speed with only minimal emulation. Otherwise, folks will stick with x86 to continue to be able to run 25+ year old collections of software and Windows on ARM won’t ever get community support.

  6. This post has been deleted by its author

  7. Annihilator Silver badge

    To be fair, x86 emulation has been done for the past 2 or 3 decades. All modern CPUs are RISC processors under the hood, with a translation layer above it converting the x86 instructions. All we're doing here is using software rather than hardware to do the translation.

    In that respect, x86 must surely be doomed now.

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