Move some bignum functions out of constant_time module
Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/library/bignum_core.h b/library/bignum_core.h
index 21a5a11..1fc5375 100644
--- a/library/bignum_core.h
+++ b/library/bignum_core.h
@@ -149,6 +149,24 @@
size_t A_limbs);
/**
+ * \brief Check if one unsigned MPI is less than another in constant
+ * time.
+ *
+ * \param A The left-hand MPI. This must point to an array of limbs
+ * with the same allocated length as \p B.
+ * \param B The right-hand MPI. This must point to an array of limbs
+ * with the same allocated length as \p A.
+ * \param limbs The number of limbs in \p A and \p B.
+ * This must not be 0.
+ *
+ * \return The result of the comparison:
+ * \c 1 if \p A is less than \p B.
+ * \c 0 if \p A is greater than or equal to \p B.
+ */
+unsigned mbedtls_mpi_core_lt_ct(const mbedtls_mpi_uint *A,
+ const mbedtls_mpi_uint *B,
+ size_t limbs);
+/**
* \brief Perform a safe conditional copy of an MPI which doesn't reveal
* whether assignment was done or not.
*