memcpy_cpu on 64bit arm

Michael Grunditz michael.grunditz at gmail.com
Fri Jan 20 16:40:10 CET 2023


Hello,

Is there any particular reason why it is empty?
My rect copy to fb in riscos uses neon. It is
a speed gain of about 40% compared to word/long word
copy from c. But I don't know how much it affects Genode.

It seems like it ends up in /* eight bytes chunks */ but isn't that a byte copy?

I have the feeling that in my case, with blit,mem copy without crop
is faster than
doing it with crop every time. Ram, accesses are proved to be very fast
on this hardware. The extra cycles for cropping might be a bottleneck.
Combined with a neon run through , testing and copying without leaving
routine could probably make a big performance gain.

But.

I am happy, as always,  to be proved wrong!

Michael



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