crypto_bigint/modular/const_monty_form/
add.rs

1//! Additions between integers in Montgomery form with a constant modulus.
2
3use super::{ConstMontyForm, ConstMontyParams};
4use crate::modular::add::{add_montgomery_form, double_montgomery_form};
5use core::ops::{Add, AddAssign};
6
7impl<MOD: ConstMontyParams<LIMBS>, const LIMBS: usize> ConstMontyForm<MOD, LIMBS> {
8    /// Adds `rhs`.
9    #[must_use]
10    pub const fn add(&self, rhs: &ConstMontyForm<MOD, LIMBS>) -> Self {
11        Self {
12            montgomery_form: add_montgomery_form(
13                &self.montgomery_form,
14                &rhs.montgomery_form,
15                &MOD::PARAMS.modulus,
16            ),
17            phantom: core::marker::PhantomData,
18        }
19    }
20
21    /// Double `self`.
22    #[must_use]
23    pub const fn double(&self) -> Self {
24        Self {
25            montgomery_form: double_montgomery_form(&self.montgomery_form, &MOD::PARAMS.modulus),
26            phantom: core::marker::PhantomData,
27        }
28    }
29}
30
31impl<MOD: ConstMontyParams<LIMBS>, const LIMBS: usize> Add<&ConstMontyForm<MOD, LIMBS>>
32    for &ConstMontyForm<MOD, LIMBS>
33{
34    type Output = ConstMontyForm<MOD, LIMBS>;
35    fn add(self, rhs: &ConstMontyForm<MOD, LIMBS>) -> ConstMontyForm<MOD, LIMBS> {
36        self.add(rhs)
37    }
38}
39
40impl<MOD: ConstMontyParams<LIMBS>, const LIMBS: usize> Add<ConstMontyForm<MOD, LIMBS>>
41    for &ConstMontyForm<MOD, LIMBS>
42{
43    type Output = ConstMontyForm<MOD, LIMBS>;
44    #[allow(clippy::op_ref)]
45    fn add(self, rhs: ConstMontyForm<MOD, LIMBS>) -> ConstMontyForm<MOD, LIMBS> {
46        self + &rhs
47    }
48}
49
50impl<MOD: ConstMontyParams<LIMBS>, const LIMBS: usize> Add<&ConstMontyForm<MOD, LIMBS>>
51    for ConstMontyForm<MOD, LIMBS>
52{
53    type Output = ConstMontyForm<MOD, LIMBS>;
54    #[allow(clippy::op_ref)]
55    fn add(self, rhs: &ConstMontyForm<MOD, LIMBS>) -> ConstMontyForm<MOD, LIMBS> {
56        &self + rhs
57    }
58}
59
60impl<MOD: ConstMontyParams<LIMBS>, const LIMBS: usize> Add<ConstMontyForm<MOD, LIMBS>>
61    for ConstMontyForm<MOD, LIMBS>
62{
63    type Output = ConstMontyForm<MOD, LIMBS>;
64    fn add(self, rhs: ConstMontyForm<MOD, LIMBS>) -> ConstMontyForm<MOD, LIMBS> {
65        &self + &rhs
66    }
67}
68
69impl<MOD: ConstMontyParams<LIMBS>, const LIMBS: usize> AddAssign<&Self>
70    for ConstMontyForm<MOD, LIMBS>
71{
72    fn add_assign(&mut self, rhs: &Self) {
73        *self = *self + rhs;
74    }
75}
76
77impl<MOD: ConstMontyParams<LIMBS>, const LIMBS: usize> AddAssign<Self>
78    for ConstMontyForm<MOD, LIMBS>
79{
80    fn add_assign(&mut self, rhs: Self) {
81        *self += &rhs;
82    }
83}
84
85#[cfg(test)]
86mod tests {
87    use crate::{
88        U256, const_monty_form, const_monty_params, modular::const_monty_form::ConstMontyParams,
89    };
90
91    const_monty_params!(
92        Modulus,
93        U256,
94        "ffffffff00000000ffffffffffffffffbce6faada7179e84f3b9cac2fc632551"
95    );
96
97    const_monty_form!(Fe, Modulus);
98
99    #[test]
100    fn add_overflow() {
101        let x =
102            U256::from_be_hex("44acf6b7e36c1342c2c5897204fe09504e1e2efb1a900377dbc4e7a6a133ec56");
103        let mut x_mod = Fe::new(&x);
104
105        let y =
106            U256::from_be_hex("d5777c45019673125ad240f83094d4252d829516fac8601ed01979ec1ec1a251");
107        let y_mod = Fe::new(&y);
108
109        x_mod += &y_mod;
110
111        let expected =
112            U256::from_be_hex("1a2472fde50286541d97ca6a3592dd75beb9c9646e40c511b82496cfc3926956");
113
114        assert_eq!(expected, x_mod.retrieve());
115    }
116}
crypto_bigint/modular/const_monty_form/add.rs

crypto_bigint/modular/const_monty_form/
add.rs
