anchor.diff:                elseif (p.eq.1.and.xsec.eq.1.and.xz.eq.1) then
                     write(*,9999) x,y
                 endif
  +              z = zsave
      15     continue
      16 continue
         stop
  
positive.code:       p = 0
        xsec = 0
        xz = 0
        do 100 i = 1,5
            ref(i) = -1.0d0
    100 continue
  
negative.code:           i = i + 3
        elseif (tag(1:3).eq.'-xz') then
            xz = 1
        elseif (tag(1:5).eq.'-clip') then
            i = i + 1
            call getarg(i,clip)
        elseif (tag(1:2).eq.'-x') then
            i = i + 1
            call getarg(i,tag)
  