diff --git a/gen164/5/rd.c b/gen164/5/rd.c
index 717d4a83b..ca6ca0cbb 100644
--- a/gen164/5/rd.c
+++ b/gen164/5/rd.c
@@ -12,6 +12,7 @@ union doub {
 
 /* declarations
 */
+  extern u2_ho_jet j2_mcj(Pt5, rd, sun)[];
   extern u2_ho_jet j2_mcj(Pt5, rd, mul)[];
   extern u2_ho_jet j2_mcj(Pt5, rd, div)[];
   extern u2_ho_jet j2_mcj(Pt5, rd, add)[];
@@ -23,6 +24,33 @@ union doub {
 
 /* functions
 */
+/* sun
+*/
+  u2_weak
+  j2_mcd(Pt5, rd, sun)(u2_wire wir_r,
+                        u2_atom a)
+  {
+    union doub b;
+    b.d = (double) u2_chub(0, a);
+      
+    return u2_ci_chubs(1, &b.c);
+  }
+
+  u2_weak
+  j2_mc(Pt5, rd, sun)(u2_wire wir_r,
+                       u2_noun cor)
+  {
+    u2_noun a;
+
+    if (u2_no == u2_mean(cor, u2_cv_sam, &a, 0)
+        || u2_no == u2_stud(a)) {
+      return u2_bl_bail(wir_r, c3__exit);
+    }
+    else {
+      return j2_mcd(Pt5, rd, sun)(wir_r, a);
+    }
+  }
+
 /* mul
 */
   u2_weak
@@ -277,6 +305,11 @@ union doub {
 
 /* structures
 */
+  u2_ho_jet
+  j2_mcj(Pt5, rd, sun)[] = {
+    { ".2", c3__lite, j2_mc(Pt5, rd, sun), Tier5_test, u2_none, u2_none },
+    { }
+  };
   u2_ho_jet
   j2_mcj(Pt5, rd, mul)[] = {
     { ".2", c3__lite, j2_mc(Pt5, rd, mul), Tier5_test, u2_none, u2_none },
@@ -320,6 +353,7 @@ union doub {
 
   u2_ho_driver
   j2_mbd(Pt5, rd)[] = {
+    { j2_sc(Pt5, rd, sun), j2_mcj(Pt5, rd, sun), 0, 0, u2_none },
     { j2_sc(Pt5, rd, mul), j2_mcj(Pt5, rd, mul), 0, 0, u2_none },
     { j2_sc(Pt5, rd, div), j2_mcj(Pt5, rd, div), 0, 0, u2_none },
     { j2_sc(Pt5, rd, add), j2_mcj(Pt5, rd, add), 0, 0, u2_none },