tree 55885cbdfc3a4a1c196ab351b1b2298caac13723
parent 0b3f497bcd4ad79a565b2d71c2d8de9b77ce1040
author David Benjamin <davidben@google.com> 1541803615 -0600
committer CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org> 1542073701 +0000

Optimize EC_GFp_mont_method's cmp_x_coordinate.

For simplicity, punt order > field or width mismatches. Analogous
optimizations are possible, but the generic path works fine and no
commonly-used curve looks hits those cases.

Before:
Did 5888 ECDSA P-384 verify operations in 3094535us (1902.7 ops/sec)
After [+6.7%]:
Did 6107 ECDSA P-384 verify operations in 3007515us (2030.6 ops/sec)

Also we can fill in p - order generically and avoid extra copies of some
constants.

Change-Id: I38e1b6d51b28ed4f8cb74697b00a4f0fbc5efc3c
Reviewed-on: https://boringssl-review.googlesource.com/c/33068
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>