|  | // 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 | 
|  |  |