linux-kernel - Re: K8, EFFICEON and CORE2 support the cmovxx instructions.

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Date:	Sat, 15 Mar 2008 22:06:32 +0100
From:	"Alexander van Heukelum" <heukelum@...tmail.fm>
To:	"H. Peter Anvin" <hpa@...or.com>,
	"Alexander van Heukelum" <heukelum@...lshack.com>
Cc:	"Ingo Molnar" <mingo@...e.hu>, "Andi Kleen" <andi@...stfloor.org>,
	"Jeremy Fitzhardinge" <jeremy@...p.org>,
	"Thomas Gleixner" <tglx@...utronix.de>,
	"LKML" <linux-kernel@...r.kernel.org>
Subject: Re: K8, EFFICEON and CORE2 support the cmovxx instructions.

On Sat, 15 Mar 2008 21:18:16 +0100, "H. Peter Anvin" <hpa@...or.com>
said:
> Alexander van Heukelum wrote:
> > K8, EFFICEON and CORE2 support the cmovxx instructions.
> > 
> > Instead of listing the cpu's that have support for the
> > cmovxx instructions, list the cpu's that don't.
> > 
> > Signed-off-by: Alexander van Heukelum <heukelum@...tmail.fm>
> > ---
> > 
> > A bit of playing resulted in:
> > 
> > CPUS="M386 M486 M586 M586TSC M586MMX M686 MPENTIUMII MPENTIUMIII"
> > CPUS=$CPUS" MPENTIUMM MPENTIUM4 MK6 MK7 MK8 MCRUSOE MEFFICEON"
> > CPUS=$CPUS" MWINCHIPC6 MWINCHIP2 MWINCHIP3D MGEODEGX1 MGEODE_LX"
> > CPUS=$CPUS" MCYRIXIII MVIAC3_2 MVIAC7 MPSC MCORE2"
> > 
> > for cpu in $CPUS
> > do
> >         echo "CONFIG_${cpu}=y" > testconfig
> >         make ARCH=i386 allnoconfig KCONFIG_ALLCONFIG=testconfig > /dev/null
> >         echo ${cpu} >> result
> >         grep X86_CMOV .config >> result
> >         echo >> result
> > done
> > 
> > I'm quite sure that K8, EFFICEON and CORE2 support HAVE_CMOV, but
> > they did not set X86_CMOV.
> > 
> 
> Crusoe has CMOV as well.

Hi hpa,

I believe you... and the Makefile_32.cpu: it gets a -march=i686. I
also found out that I missed X86_ELAN, which is treated as a i486.

Also, MGEODE_LX does not get any optimization flags. I think that
is unintentional, but what should they be?

And MPSC (Intel P4 / older Netburst based Xeon) depends on X86_64.
I would be very surprised if that one could not run 32-bit code,
though. What flags should that one get?

Thanks for pointing out I missed Crusoe. As a punishment you
can answer my questions ;).

Greetings,
    Alexander
-- 
  Alexander van Heukelum
  heukelum@...tmail.fm

-- 
http://www.fastmail.fm - Send your email first class

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