From: Laurent Desnogues <laurent.desnogues@wanadoo.fr>
To: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] qemu vs gcc4
Date: Mon, 23 Oct 2006 20:20:47 +0200 [thread overview]
Message-ID: <453D07FF.1000401@wanadoo.fr> (raw)
In-Reply-To: <453D0428.9090809@palmsource.com>
K. Richard Pixley a écrit :
> Well, perhaps. Except that with gcc, we get to leverage the ongoing gcc
> optimizations, bug fixes, new cpu support, debugger support, etc.
> Granted, not all of these are going to be relevant to the qemu
> environment, but in a contest between gcc generated code and qemu
> generated code, I'll bet on gcc most days.
>
> No doubt there are times when a gcc optimization takes so long that it
> costs more time to optimize than would be won back by the running code.
> Presumably, qemu generated code would be able to make better decisions
> here. Except that we're not talking about using gcc in real time, are
> we? So essentially we have near infinite time for optimizations.
One emulated instruction is a small C function with very little
opportunity for optimization.
On top of that, for instance, calculating flags can be done much
more efficiently at assembly level by using host flags.
All what gcc brings here is portability.
Laurent
next prev parent reply other threads:[~2006-10-23 18:19 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-10-20 18:53 [Qemu-devel] qemu vs gcc4 K. Richard Pixley
2006-10-22 22:06 ` Johannes Schindelin
2006-10-23 8:16 ` Martin Guy
2006-10-23 12:20 ` Paul Brook
2006-10-23 13:59 ` Avi Kivity
2006-10-23 14:10 ` Paul Brook
2006-10-23 14:28 ` Avi Kivity
2006-10-23 14:31 ` Paul Brook
2006-10-23 14:35 ` Avi Kivity
2006-10-23 17:41 ` K. Richard Pixley
2006-10-23 17:58 ` Paul Brook
2006-10-23 18:04 ` K. Richard Pixley
2006-10-23 18:20 ` Laurent Desnogues [this message]
2006-10-23 18:37 ` Paul Brook
2006-10-24 23:39 ` Rob Landley
2006-10-25 0:24 ` Paul Brook
2006-10-25 19:39 ` Rob Landley
2006-10-26 18:09 ` Daniel Jacobowitz
2006-10-31 16:53 ` Rob Landley
2006-10-31 19:02 ` Paul Brook
2006-10-31 20:41 ` Rob Landley
2006-10-31 22:08 ` Paul Brook
2006-10-31 22:31 ` Laurent Desnogues
2006-10-31 23:00 ` Paul Brook
2006-11-01 0:00 ` Rob Landley
2006-11-01 0:29 ` Paul Brook
2006-11-01 1:51 ` Rob Landley
2006-11-01 3:22 ` Paul Brook
2006-11-01 16:34 ` Rob Landley
2006-11-01 17:01 ` Paul Brook
2006-10-31 23:17 ` Rob Landley
2006-11-01 0:01 ` Paul Brook
2006-10-30 4:35 ` Rob Landley
2006-10-30 14:56 ` Paul Brook
2006-10-30 16:31 ` Rob Landley
2006-10-30 16:50 ` Paul Brook
2006-10-30 22:54 ` Stephen Torri
2006-10-30 23:13 ` Paul Brook
2006-10-23 1:27 ` Rob Landley
2006-10-23 1:44 ` Paul Brook
2006-10-23 1:45 ` Johannes Schindelin
2006-10-23 17:53 ` K. Richard Pixley
2006-10-23 18:08 ` Rob Landley
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