| // 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 | 
 |  | 
 | (* blackbox *) | 
 | module box( | 
 |     (* invertible_pin="INV_A" *) | 
 |     input  wire A, | 
 |     input  wire B, | 
 |  | 
 |     output wire Y | 
 | ); | 
 |  | 
 |     parameter [0:0] INV_A = 1'b0; | 
 |  | 
 | endmodule | 
 |  | 
 |  | 
 | module top( | 
 |     input  wire [1:0] di, | 
 |     output wire [5:0] do | 
 | ); | 
 |  | 
 |     wire [1:0] d; | 
 |  | 
 |     \$_NOT_ n0 (.A(di[0]), .Y(d[0])); | 
 |  | 
 |     box b00 (.A(d[0]), .B(    ), .Y(do[0])); | 
 |     box b01 (.A(d[0]), .B(    ), .Y(do[1])); | 
 |     box b02 (.A(    ), .B(d[0]), .Y(do[2])); | 
 |  | 
 |     \$_NOT_ n1 (.A(di[1]), .Y(d[1])); | 
 |  | 
 |     box b10 (.A(d[1]), .B(    ), .Y(do[3])); | 
 |     box b11 (.A(d[1]), .B(    ), .Y(do[4])); | 
 |     box b12 (.A(d[1]), .B(    ), .Y(do[5])); | 
 |  | 
 | endmodule |