set I0, 100
         set I1, 200
         set I6, 700
         bsr FUNC
         # 
         print I0  # 100, original value
         print I1  # 0, new value
         print I6  # 0, new value
         end

         # Local changes to I1 and I6 preserved
         # think of this as unlocal()  :)
FUNC:    pushi   # saves all integer registers
         set I0, 0
         set I1, 0
         set I6, 0
         save I1
         save I6
         popi
         restore I6
         restore I1
         ret