Module primitives 

Constant-time integer primitives for cryptographic arithmetic.

Core integer methods can lower to branches or table lookups on targets without the corresponding instructions. These helpers provide alternatives if value is zero-bit counting and carry propagation.

Like Choice, they use optimization barriers where needed. Their generated code should still be checked for the target and compiler in use.

Native zero counts are used when supported and advertised by the target configuration.

Macros

bitborrow 🔒

Outgoing borrow bit for a wrapping x - y - borrow_in result.

bitle 🔒

Bitwise less-than-or equal: returns 1 if x <= y, and otherwise returns 0.

bitlt 🔒

Bitwise less-than: returns 1 if x < y, and otherwise returns 0.

bitnz 🔒

Bitwise non-zero: returns 1 if x != 0, and otherwise returns 0.

borrowing_sub_primitives 🔒

comparison_primitives 🔒

Functions

borrowing_sub_inner_u32 🔒

borrowing_sub_inner_u64 🔒

borrowing_sub_mask_u32

Subtract rhs and an incoming borrow from lhs, using word-sized borrow masks.

borrowing_sub_mask_u64

Subtract rhs and an incoming borrow from lhs, using word-sized borrow masks.

borrowing_sub_u32

Subtract rhs and an incoming borrow from lhs.

borrowing_sub_u64

Subtract rhs and an incoming borrow from lhs.

le_u32 🔒

le_u64 🔒

leading_zeros_u32

Count leading zero bits, returning 32 if value is zero.

leading_zeros_u64

Count leading zero bits, returning 64 if value is zero.

lt_u32 🔒

lt_u64 🔒

nz_u32 🔒

nz_u64 🔒

overflowing_add_u64

Add two integers, returning the wrapping sum and Choice::TRUE on overflow.

overflowing_add_u128

Add two integers, returning the wrapping sum and Choice::TRUE on overflow.

trailing_zeros_u32

Count trailing zero bits, returning 32 if value is zero.

trailing_zeros_u64

Count trailing zero bits, returning 64 if value is zero.