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On Monday 02 October 2006 08:21, Danie Iliev wrote: |
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> Several days ago the guys at gentoo-am64 mailing list explained to me |
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> all these flags enable different CFLAGS optimizations which came as the |
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[SNIP] |
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Please don't confuse CFLAGS with USE flags. CFLAGS are passed on to the |
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compiler and tell it what kind of code to generate. E.g. an mmx USE flag |
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usually tells the package through a configure switch (such as --enable-mmx) |
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to autotools to enable some assembly code that uses the mmx instructions |
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instead of some fallback code which doesn't. That assembly code is written |
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manually rather than generated by the compiler (otherwise the CFLAG would |
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suffice). |
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> There is also another article which explains why these are hard-masked: |
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> |
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> http://dev.gentoo.org/~plasmaroo/devmanual/archs/amd64/ |
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Thanks, I forgot that one. The url is obsolete though: |
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http://devmanual.gentoo.org/archs/amd64/index.html |
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-- |
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Bo Andresen |
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