[Solved]CPU you selected does not support x86-64 instruction

[jlward4th]

I'm trying install Gentoo on a Core 2 Duo with EM64T. I've extracted the amd64 stage3 tar ball, but when I try to emerge something I get:

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example.c:1: error: CPU you selected does not support x86-64 instruction set

Here is my make.conf

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CFLAGS="-march=nocona -mtune=pentium-m -O2 -fomit-frame-pointer -pipe"
CHOST="x86_64-pc-linux-gnu"
CXXFLAGS="${CFLAGS}"

MAKEOPTS="-j3"

ACCEPT_KEYWORDS="~amd64"

Any ideas?

[i92guboj]

Yes, cat /proc/cpuinfo and post here.

[nixnut]

using -mtune=pentium-m in combination with -march=nocona makes no sense. You're mixing to architectures here.

[kernelOfTruth]

hm, I've noticed the same on the gentoo-wiki but I wasn't sure if that's wrong

@jlward4th:
did you get that cflags / configuration on the gentoo-wiki?

64 bit

CHOST="x86_64-pc-linux-gnu"
CFLAGS="-march=nocona -O2 -pipe"
CXXFLAGS="${CFLAGS}"

Warning: nocona is not yet verified for Core 2. Use at your own risk.

CFLAGS="-march=nocona -mtune=pentium-m -O2 -pipe

Warning: not approved! In test since 01.09.06

Bear in mind that all Core 2 Duo are dual-core CPUs so make sure that you use MAKEOPTS="-j3" in your make.conf. This doesn't affect the code but might reduce compile times.

Intel Core 2 Duo section on gentoo-wiki.com

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CFLAGS="-march=nocona -O2 -fomit-frame-pointer -pipe" 

works fine for me (Core 2 Duo, Conroe 6600)

also if you own an >= Conroe 6600
you should consider

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MAKEOPTS="-j7"

, this will cut your build-times tremendously

[jlward4th]

Yes, I did get those cflags from the gentoo-wiki. And your suggestion to drop the -mtune=pentium-m works! Thanks!

[kernelOfTruth]

ok, made some corrections / modifications to the wiki ...