pub(crate) const fn borrowing_sub(
lhs: Word,
rhs: Word,
borrow: Word,
) -> (Word, Word)Expand description
Computes lhs - rhs - borrow, using word-sized borrow masks.
The incoming borrow is the most significant bit of borrow; all other bits are ignored.
The outgoing borrow is Word::MAX if the subtraction underflows, or zero otherwise.