/********************************************************************** * Code snippet showing illegal use of const constants (not in book) * * Author: Stuart Sutherland * * (c) Copyright 2003, Sutherland HDL, Inc. *** ALL RIGHTS RESERVED *** * www.sutherland-hdl.com * * Used with permission in the book, "SystemVerilog for Design" *  By Stuart Sutherland, Simon Davidmann, and Peter Flake. *  Book copyright: 2003, Kluwer Academic Publishers, Norwell, MA, USA *  www.wkap.il, ISBN: 0-4020-7530-8 * * Revision History: *   1.00 15 Dec 2003 -- original code, as included in book *   1.01 10 Jul 2004 -- cleaned up comments, added expected results *                       to output messages * * Caveat: Expected results displayed for this code example are based * on an interpretation of the SystemVerilog 3.1 standard by the code * author or authors.  At the time of writing, official SystemVerilog * validation suites were not available to validate the example. * * RIGHT TO USE: This code example, or any portion thereof, may be * used and distributed without restriction, provided that this entire * comment block is included with the example. * * DISCLAIMER: THIS CODE EXAMPLE IS PROVIDED "AS IS" WITHOUT WARRANTY * OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED * TO WARRANTIES OF MERCHANTABILITY, FITNESS OR CORRECTNESS. IN NO * EVENT SHALL THE AUTHOR OR AUTHORS BE LIABLE FOR ANY DAMAGES, * INCLUDING INCIDENTAL OR CONSEQUENTIAL DAMAGES, ARISING OUT OF THE * USE OF THIS CODE. *********************************************************************/module test;  const bit [23:0] C1 = 7; // 24-bit constant  const int C2 = 15;       // 32-bit constant  const real C3 = 3.14;    // real constant  const C4 = 5;            // ERROR, no data type  task automatic C;    const int N = 5;  // N is a constant    // ...    N = 6; // ERROR: illegal assignment to const    $display("In task C, N = %0d (expect compile error)\n", N);  endtask  initial begin    $display("\nExpect compilation error on declaration of constant C4 and ");    $display("for assignments to constants C1 and N \n");    C1 = 8; // ERROR: illegal assignment to const    $display("\C1=%0d (expect compile error)", C1);    C; // call task    #1 $finish;  endendmodule