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On Saturday 21 August 2004 17:09, Ioannis Aslanidis wrote: |
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> Thank you. |
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> |
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> What I'm trying to do is to compile in my Athlon XP in order to use |
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> those same packages under a K6-2 and a Pentium-4. |
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> |
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> I am not sure how the order of -march and -mtune/-mcpu should be. What |
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> I want is to do code for Athlon XP without breaking the compatibility |
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> with Pentium 4 and K6-2. |
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> |
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> The flags I am currently using are the following: |
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> |
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> CFLAGS="-O3 -march=i586 -mtune=athlon-xp -mtune=k6-2 -mtune=i586 |
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> -mtune=i686 -mmmx -fomit-frame-pointer -funroll-loops -pipe |
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> -fforce-addr -fforce-mem -fmove-all-movables" |
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Well one thing that is just nonsense is to mention different mtune |
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targets. There will be one chosen. I don't know exactly which, but either |
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the first or the last. -fforce-mem is implied by O2 (and so O3). The |
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-march should probably be k6-2 as pentium4's can execute that. It is |
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further unlikely that you would need "-mmmx" in your options as it still |
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needs support in the sourcecode (it only enables access to the mmx |
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functions). Most packages use the mmx useflag to control this, not |
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CFLAGS. Also note that -O3 can and will create bugs. -O3 is not as well |
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tested as -O2 and in some cases not even faster. |
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Paul |
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ps. -mtune determines the scheduling of instructions, you can only |
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schedule in one way, you said you wanted to use athlon-xp then only |
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specify -mtune=athlon-xp |
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-- |
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Paul de Vrieze |
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Gentoo Developer |
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Mail: pauldv@g.o |
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Homepage: http://www.devrieze.net |
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