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Re: [Qemu-devel] Removal of some target CPU macros
From: |
Paul Brook |
Subject: |
Re: [Qemu-devel] Removal of some target CPU macros |
Date: |
Wed, 7 Nov 2007 23:36:20 +0000 |
User-agent: |
KMail/1.9.7 |
On Wednesday 07 November 2007, Bernhard Fischer wrote:
> On Wed, Nov 07, 2007 at 11:55:26PM +0100, Fabrice Bellard wrote:
> >Why not adding a new CPU type such as "PPC970 with hypervisor" and keep
> >the current PPC970 implementation as it is without the hypervisor mode.
> >I don't see the problem in replacing the ifdefs with a new CPU model !
> >You cannot reasonnably tell that it is uglier than the current code.
>
> IMHO same for i386sx. Without an FPU there is just no FPU. Without
> 486-specific instructions (or i586 etc. for that matter), the machine is
> just constrained to the one requested by the user.
>
> The fact that usually too many non ISA-imposed features are available
> without explicit user choice is very, very unfortunate, IMO.
> As always, features are or may be nice, iff and only if you are not
> forced to have or use them..
The i386 emulation always enables all features because noone's bothered to
teach it which ones are optional.
I have local ARM patches (hopefully will be merged into CVS soon) that
implement 5+ different ISA variants, 3 different FPUs, a SIMD vector unit and
2 completely different exception models. All in the same binary, and all of
which can be turned off if for emulating cpus that don't implement a
particular feature.
Paul
Re: [Qemu-devel] Removal of some target CPU macros, Tristan Gingold, 2007/11/08
Re: [Qemu-devel] Removal of some target CPU macros, Thiemo Seufer, 2007/11/07