verilator/test_regress/t/t_clocking_concat.v

// DESCRIPTION: Verilator: Verilog Test module
//
// This file ONLY is placed under the Creative Commons Public Domain.
// SPDX-FileCopyrightText: 2022 Antmicro Ltd
// SPDX-License-Identifier: CC0-1.0

module t (
    input clk
);

  logic [3:0] D1, D2, Q1, Q2;
  always @(posedge clk) begin
    {Q1, Q2} <= {D1, D2};
  end

  always @(posedge clk) $display("[%0t] posedge clk", $time);

  clocking cb @(posedge clk);
    input #0 Q = {Q1, Q2};
    output #0 D = {D1, D2};
  endclocking

  initial $monitor("[%0t] --> D=%x\t\tQ=%x\t\tcb.Q=%x", $time, {D1, D2}, {Q1, Q2}, cb.Q);

  int cyc = 0;
  always @(posedge clk) begin
    cyc <= cyc + 1;
    if (cyc > 1 && cb.Q != {D1 - 4'd1, D2 - 4'd1}) $stop;
    cb.D <= {D1 + 4'd1, D2 + 4'd1};
    if (cyc == 10) begin
      $write("*-* All Finished *-*\n");
      $finish;
    end
  end
endmodule