diff --git a/BLAS/SRC/drotm.f b/BLAS/SRC/drotm.f
index 450510d143..46eb283092 100644
--- a/BLAS/SRC/drotm.f
+++ b/BLAS/SRC/drotm.f
@@ -38,6 +38,10 @@
 *>    H=(          )    (          )    (          )    (          )
 *>      (DH21  DH22),   (DH21  1.D0),   (-1.D0 DH22),   (0.D0  1.D0).
 *>    SEE DROTMG FOR A DESCRIPTION OF DATA STORAGE IN DPARAM.
+*>
+*>    IF DFLAG IS NOT ONE OF THE LISTED ABOVE, THE BEHAVIOR IS UNDEFINED.
+*>    NANS IN DFLAG MAY NOT PROPAGATE TO THE OUTPUT.
+*>
 *> \endverbatim
 *
 *  Arguments:
diff --git a/BLAS/SRC/srotm.f b/BLAS/SRC/srotm.f
index a25519b465..9232e47fbe 100644
--- a/BLAS/SRC/srotm.f
+++ b/BLAS/SRC/srotm.f
@@ -39,6 +39,9 @@
 *>      (SH21  SH22),   (SH21  1.E0),   (-1.E0 SH22),   (0.E0  1.E0).
 *>    SEE  SROTMG FOR A DESCRIPTION OF DATA STORAGE IN SPARAM.
 *>
+*>    IF SFLAG IS NOT ONE OF THE LISTED ABOVE, THE BEHAVIOR IS UNDEFINED.
+*>    NANS IN SFLAG MAY NOT PROPAGATE TO THE OUTPUT.
+*>
 *> \endverbatim
 *
 *  Arguments: