用拨码开关输入两个四位二进制数，按下运算按钮后，以 led 的方式显示运算的结果。拓展 1 ．在基本功能实现前提下，增加一个清零功能。

2 ．更换显示方式，结果用数码管进行显示。

3 ．对溢出值的考虑。如果发生溢出现象，则数码管显示“ E ”。

-Use DIP switches to enter two four binary numbers, press the operation button to display the results led the operation. Expand 1. In the realization of the basic functions of the premise, to add a clear function. 2 . Replacing the display, the results with a digital tube display. 3. Consider the value of the overflow. If an overflow occurs, the digital display " E" .