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Re: NON FPU cpus - way to go

To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Subject: Re: NON FPU cpus - way to go
From: "Maciej W. Rozycki" <macro@ds2.pg.gda.pl>
Date: Thu, 8 Feb 2001 11:42:45 +0100 (MET)
Cc: Florian Lohoff <flo@rfc822.org>, linux-mips@oss.sgi.com, ralf@oss.sgi.com
In-reply-to: <E14QZie-00011I-00@the-village.bc.nu>
Organization: Technical University of Gdansk
Sender: owner-linux-mips@oss.sgi.com
On Wed, 7 Feb 2001, Alan Cox wrote:

> Its an interesting question whether it belongs in the kernel or libc. 
> Discuss ;)

 Hmm, emulating a missing part of CPU seems more natural in the kernel
mode.  It's completely transparent -- no difference to userland software
whether there is a real part or an emulator.

 The libc approach has the advantage of being unprivileged -- a fault in
an emulator cannot itself bring a system down.  It's non-transparent,
though -- it may give interesting effects when debugging. 

> Also we missed a trick on the x86 and I want to fix that one day, which is
> to have an __fpu ELF segment so if you boot an FPU emu kernel on an fpu
> box you regain 47K

 A good idea, even though hardly anyone needs the emulator for i386 these
days. ;-) 

-- 
+  Maciej W. Rozycki, Technical University of Gdansk, Poland   +
+--------------------------------------------------------------+
+        e-mail: macro@ds2.pg.gda.pl, PGP key available        +


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