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    pub const fn neg(&self) -> Self {
9        Self {
10            montgomery_form: self.montgomery_form.neg_mod(MOD::MODULUS.as_ref()),
11            phantom: self.phantom,
12        }
13    }
14}
15
16impl<MOD: ConstMontyParams<LIMBS>, const LIMBS: usize> Neg for ConstMontyForm<MOD, LIMBS> {
17    type Output = Self;
18    fn neg(self) -> Self {
19        ConstMontyForm::neg(&self)
20    }
21}
22
23impl<MOD: ConstMontyParams<LIMBS>, const LIMBS: usize> Neg for &ConstMontyForm<MOD, LIMBS> {
24    type Output = ConstMontyForm<MOD, LIMBS>;
25    fn neg(self) -> ConstMontyForm<MOD, LIMBS> {
26        ConstMontyForm::neg(self)
27    }
28}
29
30#[cfg(test)]
31mod tests {
32    use crate::{
33        const_monty_form, impl_modulus, modular::const_monty_form::ConstMontyParams, U256,
34    };
35
36    impl_modulus!(
37        Modulus,
38        U256,
39        "15477BCCEFE197328255BFA79A1217899016D927EF460F4FF404029D24FA4409"
40    );
41
42    #[test]
43    fn test_negate() {
44        let x =
45            U256::from_be_hex("77117F1273373C26C700D076B3F780074D03339F56DD0EFB60E7F58441FD3685");
46        let x_mod = const_monty_form!(x, Modulus);
47
48        let res = -x_mod;
49        let expected =
50            U256::from_be_hex("089B67BB2C124F084701AD76E8750D321385E35044C74CE457301A2A9BE061B1");
51
52        assert_eq!(res.retrieve(), expected);
53    }
54}
crypto_bigint/modular/const_monty_form/neg.rs

crypto_bigint/modular/const_monty_form/
neg.rs
