Fix for select point from table in ec_nistp scalar_mul #1719
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Previous change unified and simplified selecting a point from table by using constant_time_select_entry_from_table_8 function. Unfortunatelly, on x86 this function is significantly slower than constant_time_select_entry_from_table_w. This commit fixes the performance regression.
Measured on Intel(R) Xeon(R) Platinum 8488C:
P-384 scalar_mul from 4091 to 5461 ops/s,
P-521 scalar_mul from 2520 to 3731 ops/s.
Call-outs:
Point out areas that need special attention or support during the review process. Discuss architecture or design changes.
Testing:
How is this change tested (unit tests, fuzz tests, etc.)? Are there any testing steps to be verified by the reviewer?
By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license and the ISC license.