Generated by Foxit PDF Creator Foxit Software ttp//www.foxitsoftware.comForevaluationonly 多位二进制加法器 两个n位二进 a B 制数据与进位 cIn Full adder Cout 输入信号进行 法运算,产 Sum 生1个n位的 法和与一个进 S=A⊕B⊕C 位输出信号 ABC:+ abC:+ abc.+aBc C =AB+BC+AC
11 多位二进制加法器 S A B Ci = A= BCi ABCi ABCi ABCi + + + Co AB BCi ACi + += A B Cout Sum Cin Full adder 两个n位二进 制数据与进位 输入信号进行 加法运算，产 生1个n位的加 法和与一个进 位输出信号 Generated by Foxit PDF Creator © Foxit Software http://www.foxitsoftware.com For evaluation only
Generated by Foxit PDF Creator Foxit Software ttp//www.foxitsoftware.comForevaluationonly Express sum and carry as a function of P g, d Define 3 new variable which ONLY depend on A, B Generate(G)=AB B Propagate(P)=A⊕B arry delete Delete =A B 0 1 0 0 (G, P)=G+ PC propagate S(G,P)=Pe 0 generate Can also derive expressions for s and co based on d and p Note that we will be sometimes using an alternate definition for Propagate(P)=A+ B
12 Express Sum and Carry as a function of P, G, D Define 3 new variable which ONLY depend on A, B Generate (G) = AB Propagate (P) = A B Delete = A B Can also derive expressions for S and Co based on D and P Propagate (P) = A + B Note that we will be sometimes using an alternate definition for Generated by Foxit PDF Creator © Foxit Software http://www.foxitsoftware.com For evaluation only
Generated by Foxit PDF Creator Foxit Software ttp//www.foxitsoftware.comForevaluationonly 加法器 ■二进制加法 ■加法器结构设计 ■加法器电路设计
13 加法器 二进制加法 加法器结构设计 加法器电路设计 Generated by Foxit PDF Creator © Foxit Software http://www.foxitsoftware.com For evaluation only
Generated by Foxit PDF Creator Foxit Soft ttp//www.foxitsoftware.comForevaluation 行波进位加法器(RCA) ∑ ∑ ∑ ∑ Ao Be B A? B A3 B ◆行波进位的并行加法器 ◆问题:高位要等待低位产生进位
14 行波进位的并行加法器 问题: 高位要等待低位产生进位 行波进位加法器（RCA） Generated by Foxit PDF Creator © Foxit Software http://www.foxitsoftware.com For evaluation only