用verilog语言编写的CLA_20文件。CLA_20是20位超前进位加法器的源代码，该代码验证后功能正确，读者可以自行编写testbench代码进行验证。-With verilog language CLA 20 files. CLA 20 is 20 lookahead adder source code after the code verification function correctly, readers can write their own testbench code for verification.