| // 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 | 
 |  |