src/lib/libc/amd64/string/timingsafe_memcmp.S, branch main FreeBSD source tree lib/libc/amd64/string: add timingsafe_memcmp() assembly implementation 2023-10-15T19:25:53+00:00 Robert Clausecker fuz@FreeBSD.org 2023-10-15T19:25:53+00:00 5048c1b85506c5e0f441ee7dd98dd8d96d0a4a24 Conceptually very similar to timingsafe_bcmp(), but with comparison logic inspired by Elijah Stone's fancy memcmp. A baseline (SSE) implementation was omitted this time as I was not able to get it to perform adequately. Best I got was 8% over the scalar version for long inputs, but slower for short inputs. Sponsored by: The FreeBSD Foundation Approved by: security (cperciva) Inspired by: https://github.com/moon-chilled/fancy-memcmp Differential Revision: https://reviews.freebsd.org/D41696 
Conceptually very similar to timingsafe_bcmp(), but with comparison
logic inspired by Elijah Stone's fancy memcmp. A baseline (SSE)
implementation was omitted this time as I was not able to get it to
perform adequately.  Best I got was 8% over the scalar version for
long inputs, but slower for short inputs.

Sponsored by:	The FreeBSD Foundation
Approved by:	security (cperciva)
Inspired by:	https://github.com/moon-chilled/fancy-memcmp
Differential Revision:	https://reviews.freebsd.org/D41696