Re: When will Wine integrate an x86 CPU emulator?

[Kelly Leahy]

Not sure I agree with paragraph two of the answer...

While writing an x86 emulator (and integrating it into wine) would be quite
difficult, I don't see how the complexity has anything to do with the data
types and API functions...  A true emulator has no concept whatsoever of
data types (except the very basic data types of the cpu - x-bit word, x-bit
IEEE number, for instance), so its complexity cannot possibly depend on the
high-level data types used by the compiler generating the machine code...

Kelly

----- Original Message ----- 
From: "Francois Gouget" 
To: 
Sent: Wednesday, August 20, 2003 3:42 PM
Subject: FAQ: When will Wine integrate an x86 CPU emulator?
> Changelog:
> -
>
> documentation/faq.sgml
>
> Add an entry answering the eternal question:
> When will Wine integrate an x86 CPU emulator?
> Index: documentation/faq.sgml
>
> RCS file: /home/wine/wine/documentation/faq.sgml,v
> retrieving revision 1.13
> diff -u -r1.13 faq.sgml
> --- documentation/faq.sgml 28 Jul 2003 19:06:10 -0000 1.13
> +++ documentation/faq.sgml 20 Aug 2003 20:37:51 -0000
> @@ -130,6 +130,58 @@
>        </qandaentry>
>    <qandaentry>
> -
>  <question id="Integrate-an-x86-emulator">
> -
>    <para>When will Wine integrate an x86 CPU emulator so we can
> -
>      run Windows applications on non-x86 machines?</para>
> -
>  </question>
> -
>  <answer>
> -
>    <para>
> -
>      The short answer is 'probably never'. Remember, Wine Is Not a
> -
>      (CPU) Emulator. The long answer is that we probably don't want

or
> -
>      need to integrate one in the traditional sense.
> -
>    </para>
> -
>    <para>
> -
>      Integrating a CPU emulator in Wine would be extremely hard,
> -
>      due to the large number of Windows APIs and the complex
> -
>      datatypes they exchange. It is not uncommon for a Windows API

to
> -
>      take three or more pointers to structures composed of many

fields,
> -
>      including pointers to other complex structures. For each of

these
> -
>      we would need a conversion routine to deal with the byte order

and
> -
>      alignment issues. Furthermore, Windows also contains many

callback
> -
>      mechanisms that constitute as many extra places where we would

have
> -
>      to handle these conversion issues. Wine already has to deal

with
> -
>      16 vs. 32 bit APIs and Ansi vs. Unicode APIs which both
> -
>      introduce significant complexity. Adding support for a CPU

emulator
> -
>      inside Wine would introduce at least double that complexity and
> -
>      only serve to slow down the development of Wine.
> -
>    </para>
> -
>    <para>
> -
>      Fortunately another solution exists to run Windows applications
> -
>      on non-x86 platforms: run both Wine and the application inside

the
> -
>      CPU emulator. As long as the emulator provides a standard Unix
> -
>      environment, Wine should only need minimal modifications. What
> -
>      performance you loose due to Wine running inside the emulator
> -
>      rather than natively, you gain in complexity inside of Wine.
> -
>      Furthermore, if the emulator is fast enough to run Windows
> -
>      applications, Photoshop for instance, then it should be fast

enough
> -
>      to run that same Windows application plus Wine.
> -
>    </para>
> -
>    <para>
> -
>      Two projects have started along those lines: <ulink
> -
>      url="http://fabrice.bellard.free.fr/qemu/">QEMU</>, an
> -
>      open-source project, and <ulink
> -
>      url="http://www.transitives.com/tech_overview.htm">Dynamite</>,
> -
>      a commercial CPU emulator environment from
> -
>      <ulink url="http://www.transitives.com/">Transitives

Technologies</>
> -
>      which has been <ulink
> -
>      url="http://www.transgaming.com/news.php?newsid=37">paired
> -
>      with Wine</>.
> -
>    </para>
> -
> -
>  </answer>
> -
>  </qandaentry>
> -
> -
>  <qandaentry>
>  <question id="Why-would-anyone-want-Wine-Windows-suck">
>    <para>Why would anyone want Wine? Doesn't Windows suck?</para>
>  </question>
>
>
> -- 
> Francois Gouget         [e-mail]        http://fgouget.free.fr/
>      Linux, WinNT, MS-DOS - also known as the Good, the Bad and the Ugly.