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,P,C;
	assign	G = A_in & B_in ;
	assign	P =	A_in ^ B_in ;

	assign	C = { G[3] | (P[3]&C[2]),G[2] | (P[2]&C[1]),G[1] | (P[1]&C[0]),G[0] | (P[0]&C_1) };
	assign	S = {P[3]^C[2],P[2]^C[1],P[1]^C[0]  ,P[0]^ C_1};

	assign 	CO = C[3];
endmodule