On Monday, 11 August 2014 at 23:10:14 UTC, Klaus wrote:
Those functions are part of the memory manager (MM). Some MM have higly optimized memory copy operation (i.e realloc: if the source is overlapped with the dest...using SSE or MMX registers... etc).
I've tried using some of them sometimes. Came across a case of trying to do a compare or copy safely, but if it was under a certain size it just didn't do anything making my compression testing functions fail. This was mostly if they were under the system's default word size. Not sure why that was, I would have thought it would switch tracks and handle less efficient pieces if there was only a few of them so I didn't have to write special work-around cases.
Of course could do like M$ does, and increase the minimum size to the word length or double that for compression (NTFS does this) and a lot of speedups appear and problems go away rather than being as thorough as possible...
