Re: CRC32C Parallel Computation Optimization on ARM

On Mon, Dec 2, 2024 at 2:01 AM Dmitry Dolgov <9erthalion6@gmail.com> wrote:
>
> One side note, I think it would be great to properly cite the white
> paper the patch is referring to. Besides paying some respect to the
> authors, it will also make it easier to actually find it. After a quick
> search I found only some references to [1], but this link doesn't seem
> to be available anymore.

I found an archive:


https://web.archive.org/web/20220802143127/https://www.intel.com/content/dam/www/public/us/en/documents/white-papers/crc-iscsi-polynomial-crc32-instruction-paper.pdf

One thing I noticed is this part:

"The basic concepts in this paper are derived from and explained in detail in
the patents and pending applications [4][5][6]."
...
[4] Determining a Message Residue, Gopal et al. United States Patent 7,886,214
[5] Determining a Message Residue Gueron et al. United States Patent Application
20090019342
[6] Determining a Message Residue Gopal et al. United States Patent Application
20090158132

Searching for the first one gives

https://patents.google.com/patent/US20090019342

which says
"Status Expired - Fee Related
2029-09-03 Adjusted expiration"

On the other hand, looking at Linux kernel sources, it seems a patch
using this technique was contributed by Intel over a decade ago:

https://github.com/torvalds/linux/blob/master/arch/x86/crypto/crc32c-pcl-intel-asm_64.S

So one more thing to ask our friends at Intel.

--
John Naylor
Amazon Web Services