[U-Boot] [PATCH] lib/string: memmove: use memcpy if it is safe to do so

Peter Korsgaard jacmet at sunsite.dk
Sat Oct 29 01:28:06 CEST 2011


>>>>> "Wolfgang" == Wolfgang Denk <wd at denx.de> writes:

Hi,

 >> memmove is used in a number of performance critical places, like copying the
 >> linux kernel from nor flash to ram, so optimizing it can be interesting.
 >> 
 >> Unfortunately, an arch specific version of memmove often isn't used, and
 >> not supported at all on a number of archs (arm/mips/nds32/nios2/x86) -
 >> But memcpy typically is.

 Wolfgang> So you are adding code, making the system even less efficient?  This
 Wolfgang> sounds to be acounter-productive approach.

Well, slightly less efficient for the (uncommon) situation where
src/dest overlaps in return for significantly more efficiency for the
situation where they don't.

 Wolfgang> Can you not instead arrange for arch specific, optimized versions
 Wolfgang> memmove() to be used?

That's another option, but more work for implementers - So I would
prefer this trivial patch instead.

But I'll drop it if you disagree.

-- 
Bye, Peter Korsgaard


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