code: def get_buffer_size_in_pages(cls, address, size):
          
          if size < 0:
              size    = -size
              address = address - size
          begin, end = cls.align_address_range(address, address + size)
          # XXX FIXME
          # I think this rounding fails at least for address 0xFFFFFFFF size 1
          return int(float(end - begin) / float(cls.pageSize))
docs: Get the number of pages in use by the given buffer.
  
          @type  address: int
          @param address: Aligned memory address.
  
          @type  size: int
          @param size: Buffer size.
  
          @rtype:  int
          @return: Buffer size in number of pages.