verilator/examples/make_protect_lib/secret_impl.v

// DESCRIPTION: Verilator: --protect-lib example secret module
//
// This file ONLY is placed under the Creative Commons Public Domain.
// SPDX-FileCopyrightText: 2017 Wilson Snyder
// SPDX-License-Identifier: CC0-1.0

// This module will be used as libsecret.a or libsecret.so without
// exposing the source.

module secret_impl (
    input [31:0] a,
    input [31:0] b,
    output logic [31:0] x,
    input clk,
    input reset_l
);

  logic [31:0] accum_q;
  logic [31:0] secret_value;

  initial $display("[%0t] %m: initialized", $time);

  always @(posedge clk) begin
    if (!reset_l) begin
      accum_q <= 0;
      secret_value <= 9;
    end
    else begin
      accum_q <= accum_q + a;
      if (accum_q > 10) x <= b;
      else x <= a + b + secret_value;
    end
  end

endmodule