Messages in this thread | | | Date | Wed, 29 May 2002 13:42:02 +0200 | From | Dave Jones <> | Subject | Re: [PATCH] [2.4] [2.5] [i386] Add support for GCC 3.1 -march=pentium{-mmx,3,4} |
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On Mon, May 27, 2002 at 08:53:02AM +0000, Pavel Machek wrote: > Hi! > > > I would be (pleasantly) surprised to see gcc turn a C memcpy into faster > > assembly than our current implementation. And I'll bet > > gcc has hand-coded assembly inside itself, if gcc compiled memcpy is slower > than hand-optimized one, you found a compiler bug.
Not at all. gcc compiled memcpy just has no knowledge of things like non-temporal stores, and using mmx/sse to move 64 bits at a time instead of 32 bit registers. (It's only recently it got prefetch abilities too).
-- | Dave Jones. http://www.codemonkey.org.uk | SuSE Labs - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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