faster alternative to memcpy?

Question

I have a function that is doing memcpy, but it\'s taking up an enormous amount of cycles. Is there a faster alternative/approach than using memcpy to move a piece of memory?

Answer 1

Actually, memcpy is NOT the fastest way, especially if you call it many times. I also had some code that I really needed to speed up, and memcpy is slow because it has too many unnecessary checks. For example, it checks to see if the destination and source memory blocks overlap and if it should start copying from the back of the block rather than the front. If you do not care about such considerations, you can certainly do significantly better. I have some code, but here is perhaps an ever better version:

Very fast memcpy for image processing?.

If you search, you can find other implementations as well. But for true speed you need an assembly version.