04.03.11_snippet-1.sv

system verilog design book examples

/**********************************************************************
 * Arrays of structures (packed and unpacked)
 *
 * 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;

  typedef struct packed {  // packed structure
    int  a;
    byte b;
  } packet_t;

  typedef struct {  // unpacked structure
    int  a;
    real b;
  } data_t;

  packet_t [23:0] packet_array; // packed array of 24 structures
  data_t data_array [23:0];     // unpacked array of 24 structures

  initial begin
    $display("\n packet_array[0].a = %0d (expect 0)", packet_array[0].a);
    $display(" data_array[0].b = %1.1f (expect 0.0)\n", data_array[0].b);
    $finish;
  end
endmodule