[PATCH] msvcrt: Import memmove from musl
Paul Gofman
pgofman at codeweavers.com
Fri Aug 21 07:02:38 CDT 2020
On 8/21/20 14:51, Gabriel Ivăncescu wrote:
> FWIW "rep movsb" is supposedly the fastest when transferring larger
> blocks (I think more than 128 bytes?) on recent CPUs. The cool thing
> is that the CPU handles everything, no matter the alignment or "memcpy
> vs memmove", so it's by far the simplest, and since it knows about the
> alignment requirements of that particular CPU it can optimize it
> internally itself.
>
> Same story with "rep stosb" for memset. Unfortunately these are very
> slow on older CPUs. I think there's a CPUID flag that says whether
> they are fast, we could use that.
>
Yeah, that is (__cpuid(7):EBX & (1 << 9)).
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