diff --git a/library/bignum_mod_raw.h b/library/bignum_mod_raw.h
index b512ae0d3..b21092ff7 100644
--- a/library/bignum_mod_raw.h
+++ b/library/bignum_mod_raw.h
@@ -236,17 +236,16 @@ int mbedtls_mpi_mod_raw_from_mont_rep( mbedtls_mpi_uint *X,
 
 /** \brief  Perform fixed width modular negation.
  *
- * The size of the operation is determined by \p N. \p A must have
- * the same number of limbs as \p N.
+ * The size of the operation is determined by \p m. \p A must have
+ * the same number of limbs as \p m.
  *
  * \p X may be aliased to \p A.
  *
  * \param[out] X        The result of the modular negation.
- *                      This must be initialized. Must have enough limbs to
- *                      store the full value of the result.
+ *                      This must be initialized.
  * \param[in] A         Little-endian presentation of the input operand. This
- *                      must be smaller or equal to \p N.
- * \param[in] m         The address of the modulus related to \p A.
+ *                      must be less than or equal to \p m.
+ * \param[in] m         The modulus to use.
  */
 void mbedtls_mpi_mod_raw_neg( mbedtls_mpi_uint *X,
                               const mbedtls_mpi_uint *A,