diff --git a/gen164/5/rd.c b/gen164/5/rd.c
index ba7d608b8..c790b5d98 100644
--- a/gen164/5/rd.c
+++ b/gen164/5/rd.c
@@ -13,8 +13,11 @@ union doub {
 /* declarations
 */
   extern u2_ho_jet j2_mcj(Pt5, rd, mul)[];
+  extern u2_ho_jet j2_mcj(Pt5, rd, add)[];
 
 /* functions
+*/
+/* mul
 */
   u2_weak
   j2_mcd(Pt5, rd, mul)(u2_wire wir_r,
@@ -46,6 +49,40 @@ union doub {
     }
   }
 
+
+
+/* add
+*/
+  u2_weak
+  j2_mcd(Pt5, rd, add)(u2_wire wir_r,
+                        u2_atom a,
+                        u2_atom b)
+  {
+    union doub c, d, e;
+    c.c = u2_chub(0, a);
+    d.c = u2_chub(0, b);
+    e.d = c.d + d.d;
+      
+    return u2_ci_chubs(1, &e.c);
+  }
+
+  u2_weak
+  j2_mc(Pt5, rd, add)(u2_wire wir_r,
+                       u2_noun cor)
+  {
+    u2_noun a, b;
+
+    if ( u2_no == u2_mean(cor, u2_cv_sam_2, &a, u2_cv_sam_3, &b, 0) ||
+         u2_no == u2_stud(a) ||
+         u2_no == u2_stud(b) )
+    {
+      return u2_bl_bail(wir_r, c3__exit);
+    }
+    else {
+      return j2_mcd(Pt5, rd, add)(wir_r, a, b);
+    }
+  }
+
 /* structures
 */
   u2_ho_jet
@@ -53,10 +90,16 @@ union doub {
     { ".2", c3__lite, j2_mc(Pt5, rd, mul), Tier5_test, u2_none, u2_none },
     { }
   };
+  u2_ho_jet
+  j2_mcj(Pt5, rd, add)[] = {
+    { ".2", c3__lite, j2_mc(Pt5, rd, add), Tier5_test, u2_none, u2_none },
+    { }
+  };
 
   u2_ho_driver
   j2_mbd(Pt5, rd)[] = {
     { j2_sc(Pt5, rd, mul), j2_mcj(Pt5, rd, mul), 0, 0, u2_none },
+    { j2_sc(Pt5, rd, add), j2_mcj(Pt5, rd, add), 0, 0, u2_none },
     { }
   };