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) = qdata(i,jbc,mq)
                  else
  
positive.code:          enddo
  
  c        # Face 3
           do jbc = my-mint+1,my+mbc
              do i = 1-mbc,mx-mint
                 if (packdata) then
                    qpack(k) = qdata(i,jbc,mq)
                 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
  