题解 | #超前进位加法器#

`timescale 1ns/1ns

module huawei8//四位超前进位加法器
(
	input wire [3:0]A,
	input wire [3:0]B,
	output wire [4:0]OUT
);
 
wire [3:0] P;
wire [3:0] G;
wire [3:0] F;
wire [4:1] C;
 

//*************code***********//
CLA_4 cla_inst(.P(P),.G(G),.C_in(1'b0),.Ci(C),.Gm(),.Pm());

Add1 a1(.a(A[0]), .b(B[0]), .C_in(1'b0), .f(F[0]), .g(G[0]), .p(P[0]));
Add1 a2(.a(A[1]), .b(B[1]), .C_in(C[1]), .f(F[1]), .g(G[1]), .p(P[1]));
Add1 a3(.a(A[2]), .b(B[2]), .C_in(C[2]), .f(F[2]), .g(G[2]), .p(P[2]));
Add1 a4(.a(A[3]), .b(B[3]), .C_in(C[3]), .f(F[3]), .g(G[3]), .p(P[3]));

assign OUT = {C[4],F};
//*************code***********//
endmodule



//////////////下面是两个子模块////////

module Add1
(
		input a,
		input b,
		input C_in,
		output f,
		output g,
		output p
); 
	assign g = a | b;
	assign f = a ^ b ^ C_in;
	assign p = a & b;
endmodule
 
module CLA_4(
		input [3:0]P,
		input [3:0]G,
		input C_in,
		output [4:1]Ci,
		output Gm,
		output Pm
	);
	assign Ci[1] = P[0] | G[0];
	assign Ci[2] = P[1] | G[1] & Ci[1];
	assign Ci[3] = P[2] | G[2] & Ci[2];
	assign Ci[4] = P[3] | G[3] & Ci[3];

endmodule