Decrement memory location

def instruction_DEC_memory(self, opcode, ea, m):
        """ Decrement memory location """
        r = self.DEC(m)
#        log.debug("$%x DEC memory value $%x -1 = $%x and write it to $%x \t| %s" % (
#            self.program_counter,
#            m, r, ea,
#            self.cfg.mem_info.get_shortest(ea)
#        ))
        return ea, r & 0xff