Re: FYI: No JIT on Windows 8 for ARM

  • From: Dimter 'malkia' Stanev <malkia@xxxxxxxxx>
  • To: "luajit@xxxxxxxxxxxxx" <luajit@xxxxxxxxxxxxx>
  • Date: Thu, 10 May 2012 08:28:19 -0700

Windows ARM can live now it's own life :)

Sent from my iPad

On May 10, 2012, at 1:43 AM, Mike Pall <mike-1205@xxxxxxxxxx> wrote:

> Since the media will be all over that Windows 8/ARM vs. Mozilla
> thing this weekend, I wanted to chime in with an actual technical
> analysis:
> Windows 8/ARM only allows sandboxed apps from independent
> developers. These only have access to the WinRT API, but not the
> full WIN32 API. Yes, the WIN32 API _does_ exist on W8ARM, but only
> Internet Explorer and system processes get access to it.
> The WinRT API does not offer the equivalent of VirtualAlloc() or
> VirtualProtect() with the ability to make code executable at
> runtime. But JIT compilers absolutely require this functionality,
> which means there'll be NO INDEPENDENT JIT COMPILERS for W8ARM!
> The Internet Explorer process on W8ARM has special privileges and
> is the only one allowed to run a JIT compiler to speed up JavaScript.
> No other browser will be able to compete on performance with IE on
> W8ARM. That sure simplifies keeping up with the competition ... ;-)
> Actually, fully-functional browsers need access to a couple more
> APIs that is denied to them, too. But the inability to run a JIT
> compiler has consequences for a much wider range of software:
> !*!*!
> For W8ARM there'll be no LuaJIT (in JIT mode), no PyPy, no Java,
> no v8, just to name a few. Ditto for any software that relies on
> them (Scala, Clojure, JRuby) or embeds them.
> !*!*!
> [
> Note that Windows 8 for x86/x64 has similar restrictions for
> applications distributed via their Windows Store. But you can
> still install independent software directly. And Windows 8 is of
> course backwards compatible to Windows 7 software on x86/x64.
> But you can see where this is heading ...
> ]
> --Mike

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