|  | // Copyright (C) 2020-2021  The SymbiFlow Authors. | 
|  | // | 
|  | // Use of this source code is governed by a ISC-style | 
|  | // license that can be found in the LICENSE file or at | 
|  | // https://opensource.org/licenses/ISC | 
|  | // | 
|  | // SPDX-License-Identifier:ISC | 
|  |  | 
|  | module mux2 ( | 
|  | S, | 
|  | A, | 
|  | B, | 
|  | Y | 
|  | ); | 
|  | input S; | 
|  | input A, B; | 
|  | output reg Y; | 
|  |  | 
|  | always @(*) Y = (S) ? B : A; | 
|  | endmodule | 
|  |  | 
|  | module mux4 ( | 
|  | S, | 
|  | D, | 
|  | Y | 
|  | ); | 
|  | input [1:0] S; | 
|  | input [3:0] D; | 
|  | output Y; | 
|  |  | 
|  | reg Y; | 
|  | wire [1:0] S; | 
|  | wire [3:0] D; | 
|  |  | 
|  | always @* begin | 
|  | case (S) | 
|  | 0: Y = D[0]; | 
|  | 1: Y = D[1]; | 
|  | 2: Y = D[2]; | 
|  | 3: Y = D[3]; | 
|  | endcase | 
|  | end | 
|  | endmodule | 
|  |  | 
|  | module mux8 ( | 
|  | S, | 
|  | D, | 
|  | Y | 
|  | ); | 
|  | input [2:0] S; | 
|  | input [7:0] D; | 
|  | output Y; | 
|  |  | 
|  | reg Y; | 
|  | wire [2:0] S; | 
|  | wire [7:0] D; | 
|  |  | 
|  | always @* begin | 
|  | case (S) | 
|  | 0: Y = D[0]; | 
|  | 1: Y = D[1]; | 
|  | 2: Y = D[2]; | 
|  | 3: Y = D[3]; | 
|  | 4: Y = D[4]; | 
|  | 5: Y = D[5]; | 
|  | 6: Y = D[6]; | 
|  | 7: Y = D[7]; | 
|  | endcase | 
|  | end | 
|  | endmodule | 
|  |  | 
|  | module mux16 ( | 
|  | D, | 
|  | S, | 
|  | Y | 
|  | ); | 
|  | input [15:0] D; | 
|  | input [3:0] S; | 
|  | output Y; | 
|  |  | 
|  | assign Y = D[S]; | 
|  | endmodule | 
|  |  |