利用VHDL实现三个简单的程序：BCD加法器；ALU算术逻辑单元；简单密码锁设计，具有输入密码和数据比较两种功能，由M决定是写入还是开锁。而数据写入是采用列地址与输入数相结合的的方法，存入初始密码；开锁时，密码以输入，再输入的数据逐个与输入的一组数据比较，完全吻合则开锁。-The use of VHDL to accomplish three simple procedures: BCD adder　ALU arithmetic logic unit　simple lock design, with input passwords and data comparing the two functions, the decision written by M, or unlock. The data is used to write the column address and enter the number of combining methods into the initial password　unlock, the password to enter, and then enter the data one by one with the input a set of data comparison, the perfect match then unlock.