def dump(self):
            for y in range(0, self.rows):
                mem_row = y >> 3
                bit_mask = 1 << (y % 8)
                line = ""
                for x in range(0, self.cols):
                    mem_col = x
                    offset = mem_row + (self.rows >> 3) * mem_col
                    if self.data[offset] & bit_mask:
                        line += '*'
                    else:
                        line += ' '
                print('|'+line+'|')