ec/suite_b: Make NUM_LIMBS constants NonZeroUsize.

Author: briansmith

src/ec/suite_b/ops/elem.rs

@@ -35,8 +35,8 @@ impl NumLimbs {
 
     pub(super) const fn into(self) -> usize {
         match self {
-            NumLimbs::P256 => P256_NUM_LIMBS,
-            NumLimbs::P384 => P384_NUM_LIMBS,
+            NumLimbs::P256 => P256_NUM_LIMBS.get(),
+            NumLimbs::P384 => P384_NUM_LIMBS.get(),
         }
     }
 }

src/ec/suite_b/ops/p256.rs

@@ -16,9 +16,11 @@ use super::{
     elem::{binary_op, binary_op_assign},
     elem_sqr_mul, elem_sqr_mul_acc, PublicModulus, *,
 };
+use crate::polyfill::unwrap_const;
 use cfg_if::cfg_if;
+use core::num::NonZeroUsize;
 
-pub(super) const NUM_LIMBS: usize = 256 / LIMB_BITS;
+pub(super) const NUM_LIMBS: NonZeroUsize = unwrap_const(NonZeroUsize::new(256 / LIMB_BITS));
 
 pub static COMMON_OPS: CommonOps = CommonOps {
     num_limbs: elem::NumLimbs::P256,

src/ec/suite_b/ops/p384.rs

@@ -16,8 +16,10 @@ use super::{
     elem::{binary_op, binary_op_assign},
     elem_sqr_mul, elem_sqr_mul_acc, PublicModulus, *,
 };
+use crate::polyfill::unwrap_const;
+use core::num::NonZeroUsize;
 
-pub(super) const NUM_LIMBS: usize = 384 / LIMB_BITS;
+pub(super) const NUM_LIMBS: NonZeroUsize = unwrap_const(NonZeroUsize::new(384 / LIMB_BITS));
 
 pub static COMMON_OPS: CommonOps = CommonOps {
     num_limbs: elem::NumLimbs::P384,