vendor/crypto-bigint/src/uint/modular/inv.rs


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use crate::{modular::reduction::montgomery_reduction, CtChoice, Limb, Uint};

pub const fn inv_montgomery_form<const LIMBS: usize>(
    x: &Uint<LIMBS>,
    modulus: &Uint<LIMBS>,
    r3: &Uint<LIMBS>,
    mod_neg_inv: Limb,
) -> (Uint<LIMBS>, CtChoice) {
    let (inverse, is_some) = x.inv_odd_mod(modulus);
    (
        montgomery_reduction(&inverse.mul_wide(r3), modulus, mod_neg_inv),
        is_some,
    )
}