Add ConstMontyForm::MODULUS constant (#982)

Adds an inherent associated constant for accessing the modulus.

See also: #980

Author: tarcieri

codecov.yml

@@ -0,0 +1,5 @@
+coverage:
+  status:
+    project:
+      default:
+        threshold: 1%

src/modular/const_monty_form.rs

@@ -15,7 +15,7 @@ use super::{
     div_by_2::div_by_2,
     reduction::{montgomery_reduction, montgomery_retrieve},
 };
-use crate::{ConstChoice, ConstOne, ConstZero, One, Uint, Zero};
+use crate::{ConstChoice, ConstOne, ConstZero, Odd, One, Uint, Zero};
 use core::{fmt::Debug, marker::PhantomData};
 use subtle::{Choice, ConditionallySelectable, ConstantTimeEq};
 
@@ -77,6 +77,9 @@ impl<MOD: ConstMontyParams<LIMBS>, const LIMBS: usize> ConstMontyForm<MOD, LIMBS
         phantom: PhantomData,
     };
 
+    /// Modulus as an unsigned integer.
+    pub const MODULUS: Odd<Uint<LIMBS>> = *MOD::PARAMS.modulus();
+
     /// Instantiates a new [`ConstMontyForm`] that represents this `integer` mod `MOD`.
     pub const fn new(integer: &Uint<LIMBS>) -> Self {
         let product = integer.widening_mul(&MOD::PARAMS.r2);