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

[Nick Desaulniers]

On Fri, Sep 30, 2022 at 2:55 AM David Laight <David.Laight@xxxxxxxxxx> wrote:
>
> Oh - and why do all the labels have 'byteswap' in them?

.Lbyteswap is swapping single bytes at a time.
.L4_byteswap is swapping 4 bytes at a time.
.L8_byteswap is swapping 8 bytes at a time.
.L16_byteswap, .L16_byteswap_backwards_loop, and
.L16_byteswap_forwards_loop are swapping 16 bytes at a time.

When doing a move that has to be delicate with respect to overlap, I
thought it was helpful to know how many bytes are being swapped in a
given run of instructions. The names were chosen were based on the
comparison/guards/conditional jmps.

---

Linus pointed out that this 32b memmove looks similar to 64b
memcpy_orig.  Would you prefer me use those labels?

s/.Lbyteswap/.Lstore_1byte/
s/.L4_byteswap/.Lless_3bytes/
s/.L8_byteswap/.Lless_8bytes/
s/.L16_byteswap/.Lless_16bytes/
s/.L16_byteswap_backwards_loop/.Lcopy_backward_loop/
s/.L16_byteswap_forwards_loop/.Lcopy_forward_loop/

or something else?
-- 
Thanks,
~Nick Desaulniers