RE: [PATCH v4] x86, mem: move memmove to out of line assembler

[David Laight]

From: Nick Desaulniers
> Sent: 28 September 2022 22:05
...
> memmove is quite large and probably shouldn't be inlined due to size
> alone
..
> +	/* Decide forward/backward copy mode */
> +	cmpl	dest, src
> +	jb	.Lbackwards_header

It has to be better to do the slightly more complicated
test 'dest - src < size' (as unsigned) so that reverse
copies are only done when absolutely necessary.

Ignoring pathological cases on some cpu families the
forwards copy will benefit from hardware cache prefetch.

I also have a vague recollection of std and cld being slow.

Oh - and why do all the labels have 'byteswap' in them?

	David

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