题解 | #4bit超前进位加法器电路#

`timescale 1ns/1ns

module lca_4(
	input		[3:0]       A_in  ,
	input	    [3:0]		B_in  ,
    input                   C_1   ,
 
 	output	 wire			CO    ,
	output   wire [3:0]	    S
);
wire [3:0]G;
wire [3:0]P;
assign G = A_in&B_in; 
assign P = A_in^B_in;

wire Ci0,Ci1,Ci2;
assign Ci0=G[0]|(P[0]&C_1);
assign Ci1=G[1]|(P[1]&Ci0);
assign Ci2=G[2]|(P[2]&Ci1);
assign CO=G[3]|(P[3]&Ci2);
assign S = P^{Ci2,Ci1,Ci0,C_1};

endmodule