anchor.diff:        enddo
   
   c     # Face 2
  -      do jbc = 1-mbc,mint
  -         do i = mint+1,mx+mbc
  +      do jbc = 0,mint
  +         do i = mint+1,mx+1
               if (packdata) then
                  qpack(k) = area(i,jbc)
               else
  
positive.code: 
  
  c     # Face 0
        do j = 1-mbc,my-mint
           do ibc = 1-mbc,mint
              if (packdata) then
                 qpack(k) = area(ibc,j)
              else
  
negative.code:          enddo
  
  c        # Face 1
           do j = mint+1,my+1
              do ibc = mx-mint+1,mx+1
                 if (packdata) then
                    qpack(k) = qdata(ibc,j,mq)
                 else
  