Skip to content

Faster inversion modulo 2^k #932

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom
Draft
wants to merge 14 commits into
base: master
Choose a base branch
from
Draft

Faster inversion modulo 2^k #932

wants to merge 14 commits into from

Conversation

andrewwhitehead
Copy link
Contributor

invert_mod2k and invert_mod2k_vartime are optimized for Uint and BoxedUint (often by 95% or more), which brings the performance of invert_mod much closer to invert_odd_mod.

This depends on some of the updates in #930, and adds more functionality to UintRef for operating on limb slices in const methods. Support for operating on Odd<UintRef> or NonZero<UintRef> is also added.

@andrewwhitehead
add faster wrapping multiplication; move schoolbook multiplication me…
db67140 
…thods into a separate module

Signed-off-by: Andrew Whitehead <[email protected]>
@andrewwhitehead
faster wrapping multiplication for BoxedUint
f6f05a9 
Signed-off-by: Andrew Whitehead <[email protected]>
@andrewwhitehead
add wrapping mul benchmarks
8bb3816 
Signed-off-by: Andrew Whitehead <[email protected]>
@andrewwhitehead
restrict method to alloc feature
445781c 
Signed-off-by: Andrew Whitehead <[email protected]>
@andrewwhitehead
support unsized NonZero and Odd references
4b997bf 
Signed-off-by: Andrew Whitehead <[email protected]>
@andrewwhitehead
move invert_mod_u64 to UintRef
921a5b0 
Signed-off-by: Andrew Whitehead <[email protected]>
@andrewwhitehead
optimize invert_mod2k(_vartime)
ce7b920 
Signed-off-by: Andrew Whitehead <[email protected]>
@andrewwhitehead
add benchmarks for invert_mod2k
6915877 
Signed-off-by: Andrew Whitehead <[email protected]>
@andrewwhitehead
slightly simplify invert_mod
8d1a7c4 
Signed-off-by: Andrew Whitehead <[email protected]>
@andrewwhitehead
benchmark invert_mod2k_vartime
c9d172b 
Signed-off-by: Andrew Whitehead <[email protected]>
@andrewwhitehead
invert_mod_precision tests
01da092 
Signed-off-by: Andrew Whitehead <[email protected]>
@andrewwhitehead
fix lower_u64 on 32-bit platforms
94a69c4 
Signed-off-by: Andrew Whitehead <[email protected]>
@andrewwhitehead
fix single-limb inversion on 32-bit platforms
479e00c 
Signed-off-by: Andrew Whitehead <[email protected]>
@andrewwhitehead
fix repeated doubling
d0ff0c9 
fix repeated doubling in expand_invert_mod2k

Signed-off-by: Andrew Whitehead <[email protected]>
@tarcieri tarcieri requested review from fjarri and tarcieri August 26, 2025 12:41
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Reviewers

@fjarri fjarri Awaiting requested review from fjarri

@tarcieri tarcieri Awaiting requested review from tarcieri

Assignees
No one assigned
Labels
None yet
Projects
None yet
Milestone
No milestone
Development

Successfully merging this pull request may close these issues.
1 participant
@andrewwhitehead