diff --git a/scp.c b/scp.c
index eb61bc61..e124865c 100644
--- a/scp.c
+++ b/scp.c
@@ -9979,21 +9979,21 @@ ptr = ((char *) rptr->loc) + (idx * rptr->stride);      /* point at the starting
 
 if (rptr->size == sizeof (uint8))                       /* store the value */
     *((uint8 *) ptr) =                                  /*   using a size */
-      (uint8) (*((uint8 *) ptr) & mask | val);          /*     appropriate to */
+      ((uint8) (*((uint8 *) ptr) & mask) | val);        /*     appropriate to */
                                                         /*       the size of */
 else
     if (rptr->size == sizeof (uint16))                  /*         the underlying type */
         *((uint16 *) ptr) =
-          (uint16) (*((uint16 *) ptr) & mask | val);
+          ((uint16) (*((uint16 *) ptr) & mask) | val);
 
     else 
         if (rptr->size == sizeof (uint32))
             *((uint32 *) ptr) =
-              (uint32) (*((uint32 *) ptr) & mask | val);
+              ((uint32) (*((uint32 *) ptr) & mask) | val);
 
         else                                            /* if the element size is non-standard */
             *((t_value *) ptr) =                        /*   then access using the largest size permitted */
-              *((t_value *) ptr) & mask | val;
+              (*((t_value *) ptr) & mask) | val;
 
 if ((!(sim_switches & SWMASK ('Z'))) && 
     (rptr->flags & REG_DEPOSIT) && sim_vm_reg_update)