Add note about aliasing of operands for mbedtls_mpi_mod_raw_add()
Signed-off-by: Tom Cosgrove <tom.cosgrove@arm.com>
diff --git a/library/bignum_mod_raw.h b/library/bignum_mod_raw.h
index bcb4a15..56a9f86 100644
--- a/library/bignum_mod_raw.h
+++ b/library/bignum_mod_raw.h
@@ -158,15 +158,19 @@
/**
* \brief Perform a known-size modular addition.
*
- * Calculate `A + B modulo N` where \p A, \p B, and \p N have the same size.
+ * Calculate `A + B modulo N`.
+ *
+ * The number of limbs in each operand, and the result, is given by the
+ * modulus \p N.
+ *
+ * \p X may be aliased to \p A or \p B, or even both, but may not overlap
+ * either otherwise.
*
* \param[out] X The result of the modular addition.
* \param[in] A Little-endian presentation of the left operand. This
- * must be smaller than \p N, and have the same number of
- * limbs.
+ * must be smaller than \p N.
* \param[in] B Little-endian presentation of the right operand. This
- * must be smaller than \p N, and have the same number of
- * limbs.
+ * must be smaller than \p N.
* \param[in] N The address of the modulus.
*/
void mbedtls_mpi_mod_raw_add( mbedtls_mpi_uint *X,