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Re: [Qemu-devel] 0.9.0 and svn don't build with -march=pentium2 etc.; w
From: |
Julian Seward |
Subject: |
Re: [Qemu-devel] 0.9.0 and svn don't build with -march=pentium2 etc.; was: Latest SVN fails to build on Fedora Core 6 (same with 0.9.0) |
Date: |
Sat, 24 Mar 2007 12:55:16 +0000 |
User-agent: |
KMail/1.9.5 |
> As far as X86 is concerned i386/i486/i586 are very different from later
> generation
> processors. I am wondering whether another host and target architecture
> could be
> created called i686 that makes use of something like MMX or other
> registers in Intel
> Pentium II/III/4 and AMD Athlon to negate the lack of general purpose
> registers.
I don't see how. MMX/SSE is suitable for SIMD processing of media data
and to some extent for floating point, but is largely unusable for ad-hoc
integer computation, especially anything that involves address calculations.
> The fact that QEMU works and can be optimised on x86_64 is the only
> saving grace
> for the architecture, that is still suffering from a lack of registers
> compared to any
> other architecture.
The lack of registers isn't ideal, but it's not a big deal, and in the
grand scheme of things x86_64 has a lot going for it. The most
important of which are that (from the software side) all the hard-won
knowledge of how to compile good code for x86 carries across more or less
directly to x86_64, and (from the hardware side) hardware people already
know how to make fast, cheap x86s, so it's easy to move to making fast,
cheap x86_64s.
The problems of the gcc backend to qemu have already been discussed
extensively on this list. Stealing 3+ registers from gcc on x86 really
is asking for trouble, and I believe it is generally understood that the
best long term solution is to move to a self-contained back end that
does not use gcc for dynamic code generation.
J
- Re: [Qemu-devel] Latest SVN fails to build on Fedora Core 6 (same with 0.9.0), (continued)
- Re: [Qemu-devel] Latest SVN fails to build on Fedora Core 6 (same with 0.9.0), Tony Nelson, 2007/03/18
- Re: [Qemu-devel] Latest SVN fails to build on Fedora Core 6 (same with 0.9.0), Thomas Orgis, 2007/03/18
- Re: [Qemu-devel] Latest SVN fails to build on Fedora Core 6 (same with 0.9.0), Nigel Horne, 2007/03/18
- Re: [Qemu-devel] 0.9.0 and svn don't build with -march=pentium2 etc.; was: Latest SVN fails to build on Fedora Core 6 (same with 0.9.0), Thomas Orgis, 2007/03/22
- Re: [Qemu-devel] 0.9.0 and svn don't build with -march=pentium2 etc.; was: Latest SVN fails to build on Fedora Core 6 (same with 0.9.0), Sunil Amitkumar Janki, 2007/03/22
- Re: [Qemu-devel] 0.9.0 and svn don't build with -march=pentium2 etc.; was: Latest SVN fails to build on Fedora Core 6 (same with 0.9.0), Thomas Orgis, 2007/03/23
- Re: [Qemu-devel] 0.9.0 and svn don't build with -march=pentium2 etc.; was: Latest SVN fails to build on Fedora Core 6 (same with 0.9.0), Sunil Amitkumar Janki, 2007/03/23
- Re: [Qemu-devel] 0.9.0 and svn don't build with -march=pentium2 etc.; was: Latest SVN fails to build on Fedora Core 6 (same with 0.9.0), Paul Brook, 2007/03/23
- Re: [Qemu-devel] 0.9.0 and svn don't build with -march=pentium2 etc.; was: Latest SVN fails to build on Fedora Core 6 (same with 0.9.0), Thomas Orgis, 2007/03/23
- Re: [Qemu-devel] 0.9.0 and svn don't build with -march=pentium2 etc.; was: Latest SVN fails to build on Fedora Core 6 (same with 0.9.0), Sunil Amitkumar Janki, 2007/03/24
- Re: [Qemu-devel] 0.9.0 and svn don't build with -march=pentium2 etc.; was: Latest SVN fails to build on Fedora Core 6 (same with 0.9.0),
Julian Seward <=
- Re: [Qemu-devel] 0.9.0 and svn don't build with -march=pentium2 etc.; was: Latest SVN fails to build on Fedora Core 6 (same with 0.9.0), Thomas Orgis, 2007/03/26
- Re: [Qemu-devel] 0.9.0 and svn don't build with -march=pentium2 etc.; was: Latest SVN fails to build on Fedora Core 6 (same with 0.9.0), Rob Landley, 2007/03/28
- Re: [Qemu-devel] 0.9.0 and svn don't build with -march=pentium2 etc.; was: Latest SVN fails to build on Fedora Core 6 (same with 0.9.0), Thomas Orgis, 2007/03/29
- [Qemu-devel] QEMU Alpha target, Stuart Brady, 2007/03/29
- Re: [Qemu-devel] QEMU Alpha target, Paul Brook, 2007/03/29
- Re: [Qemu-devel] QEMU Alpha target, Stuart Brady, 2007/03/29
- Re: [Qemu-devel] QEMU Alpha target, Paul Brook, 2007/03/29
- Re: [Qemu-devel] QEMU Alpha target, J. Mayer, 2007/03/29
- Re: [Qemu-devel] 0.9.0 and svn don't build with -march=pentium2 etc.; was: Latest SVN fails to build on Fedora Core 6 (same with 0.9.0), Sunil Amitkumar Janki, 2007/03/29
- Re: [Qemu-devel] 0.9.0 and svn don't build with -march=pentium2 etc.; was: Latest SVN fails to build on Fedora Core 6 (same with 0.9.0), Stuart Brady, 2007/03/29