请问各位高手，我的程序：
                          EI
                                               LD   X001
                                               OUT   M8051
                                               LD   M8000
                                               OUT  Y000
                                                DI
                                                 FEND
                                                 I101
                                                 LD   M8013
                                                 OUT   Y001
                                                 IRET
                                                END
                            在我模拟的时候对x001置1以后，y1并没有输出呢，这是怎么回事呢，我是个初学者，谢谢大家的不吝赐教。