On 01/18/2016 12:35 PM, Michael Niedermayer wrote:
Pure logic tells me it's faster to just increment than involve a
series of multiplications.
its not so simple
theres a optimizing compiler between you and the CPU
the multiplication is a shift really, and the compiler may very well
change this to dst++, buf++ and buf < buf_end
or it might use something like p[8*i] and q[i]
i++ and a i<=0 check, the 8* can on some architectures be free as
part of addressing memory
if you are interrested in optimizing code see
http://www.agner.org/optimize/
and intels Intel 64 and IA-32 Architectures Software Developers Manual
is invaluable as a reference but not useable for other purposes than
as a reference (its too huge)
I almost expected that answer, Michael. And I do know there's a lot
going on behind the scenes. But how much is another question. And don't
you think it's cleaner to just increment a variable here? Or should I
revert to the old stuff?
Mats
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