Date: Tue, 13 Jul 2004 18:07:51 +0200 From: Johan Pettersson <manlix@demonized.net> To: Andre Guibert de Bruet <andy@siliconlandmark.com> Cc: freebsd-current@freebsd.org Subject: Re: CPUTYPE=p4 & kernel config Message-ID: <20040713180751.47cbed2b.manlix@demonized.net> In-Reply-To: <20040713104934.U24726@alpha.siliconlandmark.com> References: <200407121248.42792.ilker.ozupak@emu.edu.tr> <20040712214545.O2496@alpha.siliconlandmark.com> <20040713103802.654daae4.manlix@demonized.net> <20040713104934.U24726@alpha.siliconlandmark.com>
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On Tue, 13 Jul 2004 10:59:00 -0400 (EDT)
Andre Guibert de Bruet <andy@siliconlandmark.com> wrote:
>
> On Tue, 13 Jul 2004, Johan Pettersson wrote:
>
> > On Mon, 12 Jul 2004 22:17:56 -0400 (EDT)
> > Andre Guibert de Bruet <andy@siliconlandmark.com> wrote:
> >
> >> On Mon, 12 Jul 2004, Ilker OZUPAK wrote:
> >>
> >>> is there any kernel options that is mandatory for the
> >>> "CPUTYPE=p4" case. anything to be addded to GENERIC
> >>> or to not to be removed.
> >>
> >> Your CPU qualifies for the I686_CPU cpu directive. You may consider
> >> commenting out I{4,5}86_CPU if you are not concerned with having
> >the> kernel boot on older machines. You may also want to add "options
> >> CPU_ENABLE_SSE".
> >
> > 'CPU_ENABLE_SSE' is automatically enabled when the kernel is
> > compiled with 'cpu I686_CPU'.
>
> Pentium Pros, IIs, Xeon IIs and early Celerons are 686s but they do
> not support SSE (SIMD was introduced with the PIII, IIRC). Are you
> positive that SSE floating-point calculations are enabled with
> I686_CPU?
>
> Here's what the cpu features bitfield expands to on an older 686:
> Features=0x183fbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,P
> GE,MCA,CMOV,PAT,PSE36,MMX,FXSR>
>
> Compare this to the following, which was taken from a newer 686:
> Features=0x383fbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,P
> GE,MCA,CMOV,PAT,PSE36,MMX,FXSR,SSE>
>
> Regards,
>
> > Andre Guibert de Bruet | Enterprise Software Consultant >
> > Silicon Landmark, LLC. | http://siliconlandmark.com/ >
>From src/sys/i386/NOTES:
# CPU_ENABLE_SSE enables SSE/MMX2 instructions support. This is default
# on I686_CPU and above.
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