//======================================================================
//
// tb_sha3.v
// -----------
// Testbench for the SHA-3 core.
//
//
// Author: Joachim Strombergson, Pernd Paysan
// Copyright (c) 2015, NORDUnet A/S
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
// - Redistributions of source code must retain the above copyright notice,
//   this list of conditions and the following disclaimer.
//
// - Redistributions in binary form must reproduce the above copyright
//   notice, this list of conditions and the following disclaimer in the
//   documentation and/or other materials provided with the distribution.
//
// - Neither the name of the NORDUnet nor the names of its contributors may
//   be used to endorse or promote products derived from this software
//   without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
// IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
// PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
// TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
//======================================================================

//------------------------------------------------------------------
// Simulator directives.
//------------------------------------------------------------------
`timescale 1ns/100ps


//------------------------------------------------------------------
// Test module.
//------------------------------------------------------------------
module tb_sha256();

  //----------------------------------------------------------------
  // Internal constant and parameter definitions.
  //----------------------------------------------------------------
  parameter DEBUG = 0;

  parameter CLK_HALF_PERIOD = 2;
  parameter CLK_PERIOD = 2 * CLK_HALF_PERIOD;


  //----------------------------------------------------------------
  // Register and Wire declarations.
  //----------------------------------------------------------------
  reg [31 : 0] cycle_ctr;
  reg [31 : 0] error_ctr;
  reg [31 : 0] tc_ctr;

  reg           tb_clk;
  reg           tb_reset_n;
  reg           tb_cs;
  reg           tb_we;
  reg [7 : 0]   tb_address;
  reg [31 : 0]  tb_write_data;
  wire [31 : 0] tb_read_data;
  wire          tb_error;

  reg [31 : 0]  read_data;
  reg [255 : 0] digest_data;


  //----------------------------------------------------------------
  // Device Under Test.
  //----------------------------------------------------------------
  sha3 dut(
           .clk(tb_clk),
           .reset_n(tb_reset_n),

           .cs(tb_cs),
           .we(tb_we),


           .address(tb_address),
           .write_data(tb_write_data),
           .read_data(tb_read_data),
           .error(tb_error)
           );


  //----------------------------------------------------------------
  // clk_gen
  //
  // Clock generator process.
  //----------------------------------------------------------------
  always
    begin : clk_gen
      #CLK_HALF_PERIOD tb_clk = !tb_clk;
    end // clk_gen


  //----------------------------------------------------------------
  // sys_monitor
  //
  // Generates a cycle counter and displays information about
  // the dut as needed.
  //----------------------------------------------------------------
  always
    begin : sys_monitor
      #(2 * CLK_HALF_PERIOD);
      cycle_ctr = cycle_ctr + 1;
    end


  //----------------------------------------------------------------
  // reset_dut()
  //
  // Toggles reset to force the DUT into a well defined state.
  //----------------------------------------------------------------
  task reset_dut();
    begin
      $display("*** Toggle reset.");
      tb_reset_n = 0;
      #(4 * CLK_HALF_PERIOD);
      tb_reset_n = 1;
    end
  endtask // reset_dut


  //----------------------------------------------------------------
  // init_sim()
  //
  // Initialize all counters and testbed functionality as well
  // as setting the DUT inputs to defined values.
  //----------------------------------------------------------------
  task init_sim();
    begin
      cycle_ctr     = 32'h00000000;
      error_ctr     = 32'h00000000;
      tc_ctr        = 32'h00000000;

      tb_clk        = 0;
      tb_reset_n    = 0;
      tb_cs         = 0;
      tb_we         = 0;
      tb_address    = 6'h00;
      tb_write_data = 32'h00000000;
    end
  endtask // init_dut


  //----------------------------------------------------------------
  // display_test_result()
  //
  // Display the accumulated test results.
  //----------------------------------------------------------------
  task display_test_result();
    begin
      if (error_ctr == 0)
        begin
          $display("*** All %02d test cases completed successfully.", tc_ctr);
        end
      else
        begin
          $display("*** %02d test cases completed.", tc_ctr);
          $display("*** %02d errors detected during testing.", error_ctr);
        end
    end
  endtask // display_test_result


  //----------------------------------------------------------------
  // wait_ready()
  //
  // Wait for the ready flag in the dut to be set.
  // (Actually we wait for either ready or valid to be set.)
  //
  // Note: It is the callers responsibility to call the function
  // when the dut is actively processing and will in fact at some
  // point set the flag.
  //----------------------------------------------------------------
  task wait_ready();
    begin
      read_data = 0;

      while (read_data == 0)
        begin
          read_word(ADDR_STATUS);
        end
    end
  endtask // wait_ready


  //----------------------------------------------------------------
  // single_block_test()
  //
  //
  // Perform test of a single block digest.
  //----------------------------------------------------------------
  task single_block_test(input [511 : 0] block,
                         input [255 : 0] expected);
    begin
      $display("*** TC%01d - Single block test started.", tc_ctr);

      $display("*** TC%01d - Single block test done.", tc_ctr);
      tc_ctr = tc_ctr + 1;
    end
  endtask // single_block_test


  //----------------------------------------------------------------
  // double_block_test()
  //
  //
  // Perform test of a double block digest. Note that we check
  // the digests for both the first and final block.
  //----------------------------------------------------------------
  task double_block_test(input [511 : 0] block0,
                         input [255 : 0] expected0,
                         input [511 : 0] block1,
                         input [255 : 0] expected1
                        );
    begin
      $display("*** TC%01d - Double block test started.", tc_ctr);

      $display("*** TC%01d - Double block test done.", tc_ctr);
      tc_ctr = tc_ctr + 1;
    end
  endtask // double_block_test


  //----------------------------------------------------------------
  // sha3_test
  // The main test functionality.
  //----------------------------------------------------------------
  initial
    begin : sha3_test
      reg [511 : 0] tc0;
      reg [255 : 0] res0;

      reg [511 : 0] tc1_0;
      reg [255 : 0] res1_0;
      reg [511 : 0] tc1_1;
      reg [255 : 0] res1_1;

      $display("   -- Testbench for sha3 started --");

      init_sim();
      reset_dut();

      $display("   -- Testbench for sha3 done. --");
      $finish;
    end // sha3_test
endmodule // tb_sha3

//======================================================================
// EOF tb_sha3.v
//======================================================================