crypto_bigint/modular/const_monty_form/
neg.rs

1//! Negations of integers in Montgomery form with a constant modulus.
2
3use super::{ConstMontyForm, ConstMontyParams};
4use core::ops::Neg;
5
6impl<MOD: ConstMontyParams<LIMBS>, const LIMBS: usize> ConstMontyForm<MOD, LIMBS> {
7    /// Negates the number.
8    #[must_use]
9    pub const fn neg(&self) -> Self {
10        Self {
11            montgomery_form: self
12                .montgomery_form
13                .neg_mod(MOD::PARAMS.modulus.as_nz_ref()),
14            phantom: self.phantom,
15        }
16    }
17}
18
19impl<MOD: ConstMontyParams<LIMBS>, const LIMBS: usize> Neg for ConstMontyForm<MOD, LIMBS> {
20    type Output = Self;
21    fn neg(self) -> Self {
22        ConstMontyForm::neg(&self)
23    }
24}
25
26impl<MOD: ConstMontyParams<LIMBS>, const LIMBS: usize> Neg for &ConstMontyForm<MOD, LIMBS> {
27    type Output = ConstMontyForm<MOD, LIMBS>;
28    fn neg(self) -> ConstMontyForm<MOD, LIMBS> {
29        ConstMontyForm::neg(self)
30    }
31}
32
33#[cfg(test)]
34mod tests {
35    use crate::{
36        U256, const_monty_form, const_monty_params, modular::const_monty_form::ConstMontyParams,
37    };
38
39    const_monty_params!(
40        Modulus,
41        U256,
42        "15477BCCEFE197328255BFA79A1217899016D927EF460F4FF404029D24FA4409"
43    );
44
45    const_monty_form!(Fe, Modulus);
46
47    #[test]
48    fn test_negate() {
49        let x =
50            U256::from_be_hex("77117F1273373C26C700D076B3F780074D03339F56DD0EFB60E7F58441FD3685");
51        let x_mod = Fe::new(&x);
52
53        let res = -x_mod;
54        let expected =
55            U256::from_be_hex("089B67BB2C124F084701AD76E8750D321385E35044C74CE457301A2A9BE061B1");
56
57        assert_eq!(res.retrieve(), expected);
58    }
59}
crypto_bigint/modular/const_monty_form/neg.rs

crypto_bigint/modular/const_monty_form/
neg.rs
