通过4位加法器实现32位加法器，使用串行进位的方式首先设计一个8位全加器，然后在8位全加器的基础上设计实现32位全加器(A 32 bit adder is implemented through a 4 bit adder. First, a 8 bit full adder is designed using serial carry. Then, a 32 bit full adder is designed on the basi