Subversion Repositories tiny_tate_bilinear_pairing

/*

 * Copyright 2012, Homer Hsing <homer.hsing@gmail.com>

 *

 * 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.

 */

/*

 * the module of constants

 *

 * addr  out  effective

 *    1   0     1

 *    2   1     1

 *    4   +     1

 *    8   -     1

 *   16 cubic   1

 * other  0     0

 */

module const (clk, addr, out, effective);

    input clk;

    input [5:0] addr;

    output reg [197:0] out;

    output reg effective; // active high if out is effective

    always @ (posedge clk)

      begin

         effective <= 1;

         case (addr)

            1:  out <= 198'd0;

            2:  out <= 198'd1;

            4:  out <= {6'b000101, 192'd0};

            8:  out <= {6'b001001, 192'd0};

            16: out <= {6'b010101, 192'd0};

            default:

               begin out <= 198'd0; effective <= 0; end

         endcase

      end

endmodule