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Pse
Apprentice
Joined: 01 Mar 2005
Posts: 188
Location: by the plate river
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 Posted: Thu Mar 02, 2006 8:36 am Post subject: No MMX in Inkscape 0.43 for AMD64? |
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I was recompiling Inkscape 0.43 when I caught the output of the configuration script going through the console. To my surprise it showed MMX was disabled. Shouldn't MMX be enabled by default on AMD64? Is there something wrong in Inkscape's ebuild? Or is this suppossed to happen? I've gone through Bugzilla and the forums and found nothing about this  |
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Akhouk
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Joined: 23 May 2003
Posts: 476
Location: The Two Niles, Africa
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| Posted: Thu Mar 02, 2006 9:33 am Post subject: |
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I am not sure about inkscape in particular but usually the MMX extensions means using assembly instructions to make certain routines quicker. These assemlbey instructions are written for 32bit system so using them on a 64bit system won't work.
All AMD64 systems have MMX...but they can't run the 32bit assembley instructions within a 64 bit binary.
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Pse
Apprentice
Joined: 01 Mar 2005
Posts: 188
Location: by the plate river
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| Posted: Thu Mar 02, 2006 9:49 am Post subject: |
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| I'm not really sure about what you say. I thought MMX was enabled by default on AMD64 (as well as SSE, SSE2, MMXEXT, 3Dnow, 3DnowPRO). Check GCC's man pages, march=athlon64. I think it's certainly possible to use MMX on AMD64. |
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Akhouk
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Joined: 23 May 2003
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Location: The Two Niles, Africa
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| Posted: Thu Mar 02, 2006 11:40 am Post subject: |
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| Pse wrote: | | I'm not really sure about what you say. I thought MMX was enabled by default on AMD64 (as well as SSE, SSE2, MMXEXT, 3Dnow, 3DnowPRO). Check GCC's man pages, march=athlon64. I think it's certainly possible to use MMX on AMD64. |
There are two separte issues. All AMD64 processors are all mmx compatible so yes, if you are talking about gcc optimisations then they will always be set for amd64.
The USE flags are not dealing though with mmx gcc optimisations. They are dealing with parts of the code written in assembly language particularly for mmx optimisations.The assembly contains raw 32bit mmx instructions that won't work on a 64 bit instruction set. If the MMX USE flag was only switching on gcc extensions this would have been done from the CFLAGS.
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Gentoo on AMD64
