verilator/test_regress/t/t_vpi_zero_time_cb.v

// DESCRIPTION: Verilator: Verilog Test module
//
// Copyright 2010 by Wilson Snyder. This program is free software; you can
// redistribute it and/or modify it under the terms of either the GNU
// Lesser General Public License Version 3 or the Perl Artistic License
// Version 2.0.

module t (/*AUTOARG*/
   // Inputs
   input clk
   );

`ifndef VERILATOR
   reg   clk_r = 0;
   always #10 clk_r = ~clk_r;
   assign clk = clk_r;
`endif

   reg          onebit          /*verilator public_flat_rw @(posedge clk) */;
   reg [2:1]    twoone          /*verilator public_flat_rw @(posedge clk) */;
   reg [2:1]    fourthreetwoone[4:3] /*verilator public_flat_rw @(posedge clk) */;

   reg [61:0]   quads[3:2]      /*verilator public_flat_rw @(posedge clk) */;

   reg [31:0]      count        /*verilator public_flat_rd */;
   reg [31:0]      half_count   /*verilator public_flat_rd */;

   reg [7:0]       text_byte    /*verilator public_flat_rw @(posedge clk) */;
   reg [15:0]      text_half    /*verilator public_flat_rw @(posedge clk) */;
   reg [31:0]      text_word    /*verilator public_flat_rw @(posedge clk) */;
   reg [63:0]      text_long    /*verilator public_flat_rw @(posedge clk) */;
   reg [511:0]     text         /*verilator public_flat_rw @(posedge clk) */;

   integer        status;

   sub sub();

   // Test loop
   initial begin
      count = 0;
      onebit = 1'b0;
      fourthreetwoone[3] = 0;  // stop icarus optimizing away
      text_byte = "B";
      text_half = "Hf";
      text_word = "Word";
      text_long = "Long64b";
      text = "Verilog Test module";

/*
      if (status!=0) begin
         $write("%%Error: t_vpi_var.cpp:%0d: C Test failed\n", status);
         $stop;
      end
      $write("%%Info: Checking results\n");
      if (onebit != 1'b1) $stop;
      if (quads[2] != 62'h12819213_abd31a1c) $stop;
      if (quads[3] != 62'h1c77bb9b_3784ea09) $stop;
      if (text_byte != "A") $stop;
      if (text_half != "T2") $stop;
      if (text_word != "Tree") $stop;
      if (text_long != "44Four44") $stop;
      if (text != "lorem ipsum") $stop;
 */
   end

   always @(posedge clk) begin
      count <= count + 2;
      if (count[1])
        half_count <= half_count + 2;

      if (count == 1000) begin
//       $write("*-* All Finished *-*\n");
         $finish;
      end
   end

   genvar i;
   generate
      for (i=1; i<=128; i=i+1) begin : arr
         arr #(.LENGTH(i)) arr();
      end
   endgenerate

endmodule : t

module sub;
   reg subsig1 /*verilator public_flat_rd*/;
   reg subsig2 /*verilator public_flat_rd*/;
`ifdef iverilog
   // stop icarus optimizing signals away
   wire redundant = subsig1 | subsig2;
`endif
endmodule : sub

module arr;

   parameter LENGTH = 1;

   reg [LENGTH-1:0] sig /*verilator public_flat_rw*/;
   reg [LENGTH-1:0] rfr /*verilator public_flat_rw*/;

   reg            check /*verilator public_flat_rw*/;
   reg          verbose /*verilator public_flat_rw*/;

   initial begin
      sig = {LENGTH{1'b0}};
      rfr = {LENGTH{1'b0}};
   end

   always @(posedge check) begin
      if (verbose) $display("%m : %x %x", sig, rfr);
      if (check && sig != rfr) $stop;
      check <= 0;
   end

endmodule : arr