Circuits--Combinational--Basic

1.wire

module top_module (
    input in,
    output out);
 
    wire w;
    assign w=in;
    assign out=w;
endmodule

2.GND

module top_module (
    output out);
    
   assign out=1'b0;
endmodule

3.NOR

module top_module (
    input in1,
    input in2,
    output out);
    
    assign out=~(in1|in2);
 
endmodule

4.Another gate

module top_module (
    input in1,
    input in2,
    output out);
    
    assign out=in1&(~in2);
 
endmodule

5.two gates

module top_module (
    input in1,
    input in2,
    input in3,
    output out);
    
    assign out=in3^(~(in1^in2));
 
endmodule

6.More logic gates

module top_module( 
    input a, b,
    output out_and,
    output out_or,
    output out_xor,
    output out_nand,
    output out_nor,
    output out_xnor,
    output out_anotb
);
    
    assign out_a