Daniel Iliev
Wed, 25 Oct 2006 10:05:35 -0700
Simon Stelling wrote: > Hi all, > > Back in May 2005 we made the decision to not use the assembler USE > flags because AMD64 was not affected by the "lots of sub-arches" > problem and instead just enable SIMD code where possible. As a result > of this, the 3dnow, 3dnowext, mmx, mmxext, sse and sse2 USE flags got > masked. > This decision turned out to be not the best. Intel's EM64T processors > don't support 3dnow and 3dnowext, there are AMD64s with and without > SSE3 support. The "one size fits all" idea simply is no longer true. > Starting with portage 2.1.2_pre3-r4, there is support to force USE > flags on or off on a per-package basis. This means less ebuild hackery > for us, and so I went and checked the ~50 packages with mentioned USE > flags. > > The result is that the assembler USE flags convey their actual meaning > again IF AND ONLY IF you use >=portage-2.1.2_pre3-r4. I suggest you to > stick at least "mmx mmxext sse sse2" into your USE flags, as this is > the common denominator of all AMD64s. If your processor supports it, > 3dnow and 3dnowext might be worth adding too. > > *For users of portage versions prior to 2.1.2_pre3-r4 nothing > changes*, but I'd still recommend to add the USE flags. They will > become effective as soon as you upgrade portage. > > In a nutshell: > > 1. add "mmx mmxext sse sse2" to your USE flags > 2. emerge -u portage > 3. emerge -NuD world > > If you experience any build failures, please file a bug report on > http://bugs.gentoo.org/ > > Thank you for your attention, the team wishes you a convenient flight. >
What about enabling those extensions via C[XX]FLAGS? Is this still a bad idea? -- Best regards, Daniel -- gentoo-amd64@gentoo.org mailing list