| // Copyright 2020-2022 F4PGA Authors | 
 | // | 
 | // Licensed under the Apache License, Version 2.0 (the "License"); | 
 | // you may not use this file except in compliance with the License. | 
 | // You may obtain a copy of the License at | 
 | // | 
 | //     http://www.apache.org/licenses/LICENSE-2.0 | 
 | // | 
 | // Unless required by applicable law or agreed to in writing, software | 
 | // distributed under the License is distributed on an "AS IS" BASIS, | 
 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | 
 | // See the License for the specific language governing permissions and | 
 | // limitations under the License. | 
 | // | 
 | // SPDX-License-Identifier: Apache-2.0 | 
 |  | 
 | 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 | 
 |  |