//======================================================================
//
// tb_sha1.v
// ---------
// Testbench for the SHA-1 top level wrapper.
//
//
// Author: Joachim Strombergson
// Copyright (c) 2014 SUNET
// 
// Redistribution and use in source and binary forms, with or 
// without modification, are permitted provided that the following 
// conditions are met: 
// 
// 1. Redistributions of source code must retain the above copyright 
//    notice, this list of conditions and the following disclaimer. 
// 
// 2. 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. 
// 
// 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 OWNER 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/10ps

module tb_sha1();
  
  //----------------------------------------------------------------
  // Internal constant and parameter definitions.
  //----------------------------------------------------------------
  parameter DEBUG = 0;

  parameter CLK_HALF_PERIOD = 2;
  
  parameter ADDR_NAME0       = 8'h00;
  parameter ADDR_NAME1       = 8'h01;
  parameter ADDR_VERSION     = 8'h02;

  parameter ADDR_CTRL        = 8'h08;
  parameter CTRL_INIT_BIT    = 0;
  parameter CTRL_NEXT_BIT    = 1;
  parameter CTRL_INIT_VALUE  = 8'h01;
  parameter CTRL_NEXT_VALUE  = 8'h02;

  parameter ADDR_STATUS      = 8'h09;
  parameter STATUS_READY_BIT = 0;
  parameter STATUS_VALID_BIT = 1;
                             
  parameter ADDR_BLOCK0    = 8'h10;
  parameter ADDR_BLOCK1    = 8'h11;
  parameter ADDR_BLOCK2    = 8'h12;
  parameter ADDR_BLOCK3    = 8'h13;
  parameter ADDR_BLOCK4    = 8'h14;
  parameter ADDR_BLOCK5    = 8'h15;
  parameter ADDR_BLOCK6    = 8'h16;
  parameter ADDR_BLOCK7    = 8'h17;
  parameter ADDR_BLOCK8    = 8'h18;
  parameter ADDR_BLOCK9    = 8'h19;
  parameter ADDR_BLOCK10   = 8'h1a;
  parameter ADDR_BLOCK11   = 8'h1b;
  parameter ADDR_BLOCK12   = 8'h1c;
  parameter ADDR_BLOCK13   = 8'h1d;
  parameter ADDR_BLOCK14   = 8'h1e;
  parameter ADDR_BLOCK15   = 8'h1f;
                             
  parameter ADDR_DIGEST0   = 8'h20;
  parameter ADDR_DIGEST1   = 8'h21;
  parameter ADDR_DIGEST2   = 8'h22;
  parameter ADDR_DIGEST3   = 8'h23;
  parameter ADDR_DIGEST4   = 8'h24;

  
  //----------------------------------------------------------------
  // 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_write_read;
  reg [7 : 0]   tb_address;
  reg [31 : 0]  tb_data_in;
  wire [31 : 0] tb_data_out;

  reg [31 : 0]  read_data;
  reg [159 : 0] digest_data;
  
  
  //----------------------------------------------------------------
  // Device Under Test.
  //----------------------------------------------------------------
  sha1 dut(
             .clk(tb_clk),
             .reset_n(tb_reset_n),
             
             .cs(tb_cs),
             .write_read(tb_write_read),
             
             .address(tb_address),
             .data_in(tb_data_in),
             .data_out(tb_data_out)
            );
  

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

  //----------------------------------------------------------------
  // sys_monitor
  //----------------------------------------------------------------
  always
    begin : sys_monitor
      #(2 * CLK_HALF_PERIOD);
      cycle_ctr = cycle_ctr + 1;
    end

  
  //----------------------------------------------------------------
  // dump_dut_state()
  //
  // Dump the state of the dump when needed.
  //----------------------------------------------------------------
  task dump_dut_state();
    begin
    end
  endtask // dump_dut_state
  
  
  //----------------------------------------------------------------
  // reset_dut()
  //----------------------------------------------------------------
  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_write_read = 0;
      tb_address    = 6'h00;
      tb_data_in    = 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
  

  //----------------------------------------------------------------
  // read_word()
  //
  // Read a data word from the given address in the DUT.
  // the word read will be available in the global variable
  // read_data.
  //----------------------------------------------------------------
  task read_word(input [7 : 0]  address);
    begin
      tb_address = address;
      tb_cs = 1;
      tb_write_read = 0;
      #(2 * CLK_HALF_PERIOD);
      read_data = tb_data_out;
      tb_cs = 0;

      if (DEBUG)
        begin
          $display("*** Reading 0x%08x from 0x%02x.", read_data, address);
          $display("");
        end
    end
  endtask // read_word
  

  //----------------------------------------------------------------
  // write_word()
  //
  // Write the given word to the DUT using the DUT interface.
  //----------------------------------------------------------------
  task write_word(input [7 : 0]  address,
                  input [31 : 0] word);
    begin
      if (DEBUG)
        begin
          $display("*** Writing 0x%08x to 0x%02x.", word, address);
          $display("");
        end
         
      tb_address = address;
      tb_data_in = word;
      tb_cs = 1;
      tb_write_read = 1;
      #(2 * CLK_HALF_PERIOD);
      tb_cs = 0;
      tb_write_read = 0;
    end
  endtask // write_word

  
  //----------------------------------------------------------------
  // write_block()
  //
  // Write the given block to the dut.
  //----------------------------------------------------------------
  task write_block(input [511 : 0] block);
    begin
      write_word(ADDR_BLOCK0,  block[511 : 480]);
      write_word(ADDR_BLOCK1,  block[479 : 448]);
      write_word(ADDR_BLOCK2,  block[447 : 416]);
      write_word(ADDR_BLOCK3,  block[415 : 384]);
      write_word(ADDR_BLOCK4,  block[383 : 352]);
      write_word(ADDR_BLOCK5,  block[351 : 320]);
      write_word(ADDR_BLOCK6,  block[319 : 288]);
      write_word(ADDR_BLOCK7,  block[287 : 256]);
      write_word(ADDR_BLOCK8,  block[255 : 224]);
      write_word(ADDR_BLOCK9,  block[223 : 192]);
      write_word(ADDR_BLOCK10, block[191 : 160]);
      write_word(ADDR_BLOCK11, block[159 : 128]);
      write_word(ADDR_BLOCK12, block[127 :  96]);
      write_word(ADDR_BLOCK13, block[95  :  64]);
      write_word(ADDR_BLOCK14, block[63  :  32]);
      write_word(ADDR_BLOCK15, block[31  :   0]);
    end
  endtask // write_block

  
  //----------------------------------------------------------------
  // check_name_version()
  //
  // Read the name and version from the DUT.
  //----------------------------------------------------------------
  task check_name_version();
    reg [31 : 0] name0;
    reg [31 : 0] name1;
    reg [31 : 0] version;
    begin

      read_word(ADDR_NAME0);
      name0 = read_data;
      read_word(ADDR_NAME1);
      name1 = read_data;
      read_word(ADDR_VERSION);
      version = read_data;

      $display("DUT name: %c%c%c%c%c%c%c%c",
               name0[31 : 24], name0[23 : 16], name0[15 : 8], name0[7 : 0],
               name1[31 : 24], name1[23 : 16], name1[15 : 8], name1[7 : 0]);
      $display("DUT version: %c%c%c%c",
               version[31 : 24], version[23 : 16], version[15 : 8], version[7 : 0]);
    end
  endtask // check_name_version
  

  //----------------------------------------------------------------
  // read_digest()
  //
  // Read the digest in the dut. The resulting digest will be
  // available in the global variable digest_data.
  //----------------------------------------------------------------
  task read_digest();
    begin
      read_word(ADDR_DIGEST0);
      digest_data[159 : 128] = read_data;
      read_word(ADDR_DIGEST1);
      digest_data[127 :  96] = read_data;
      read_word(ADDR_DIGEST2);
      digest_data[95  :  64] = read_data;
      read_word(ADDR_DIGEST3);
      digest_data[63  :  32] = read_data;
      read_word(ADDR_DIGEST4);
      digest_data[31  :   0] = read_data;
    end
  endtask // read_digest
    
  
  //----------------------------------------------------------------
  // single_block_test()
  //
  //
  // Perform test of a single block digest.
  //----------------------------------------------------------------
  task single_block_test([511 : 0] block,
                         [159 : 0] expected);
    begin
      $display("*** TC%01d - Single block test started.", tc_ctr); 
     
      write_block(block);
      write_word(ADDR_CTRL, CTRL_INIT_VALUE);
      write_word(ADDR_CTRL, 8'h00);
      wait_ready();
      read_digest();

      if (digest_data == expected)
        begin
          $display("TC%01d: OK.", tc_ctr);
        end
      else
        begin
          $display("TC%01d: ERROR.", tc_ctr);
          $display("TC%01d: Expected: 0x%040x", tc_ctr, expected);
          $display("TC%01d: Got:      0x%040x", tc_ctr, digest_data);
          error_ctr = error_ctr + 1;
        end
      $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([511 : 0] block0,
                         [159 : 0] expected0,
                         [511 : 0] block1,
                         [159 : 0] expected1
                        );
    begin
      $display("*** TC%01d - Double block test started.", tc_ctr); 

      // First block
      write_block(block0);
      write_word(ADDR_CTRL, CTRL_INIT_VALUE);
      write_word(ADDR_CTRL, 8'h00);
      wait_ready();
      read_digest();

      if (digest_data == expected0)
        begin
          $display("TC%01d first block: OK.", tc_ctr);
        end
      else
        begin
          $display("TC%01d: ERROR in first digest", tc_ctr);
          $display("TC%01d: Expected: 0x%040x", tc_ctr, expected0);
          $display("TC%01d: Got:      0x%040x", tc_ctr, digest_data);
          error_ctr = error_ctr + 1;
        end

      // Final block
      write_block(block1);
      write_word(ADDR_CTRL, CTRL_NEXT_VALUE);
      write_word(ADDR_CTRL, 8'h00);
      wait_ready();
      read_digest();
      
      if (digest_data == expected1)
        begin
          $display("TC%01d final block: OK.", tc_ctr);
        end
      else
        begin
          $display("TC%01d: ERROR in final digest", tc_ctr);
          $display("TC%01d: Expected: 0x%040x", tc_ctr, expected1);
          $display("TC%01d: Got:      0x%040x", tc_ctr, digest_data);
          error_ctr = error_ctr + 1;
        end

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

    
  //----------------------------------------------------------------
  // sha1_test
  // The main test functionality. 
  //----------------------------------------------------------------
  initial
    begin : sha1_test
      reg [511 : 0] tc1;
      reg [159 : 0] res1;

      reg [511 : 0] tc2_1;
      reg [159 : 0] res2_1;
      reg [511 : 0] tc2_2;
      reg [159 : 0] res2_2;

      $display("   -- Testbench for sha1 started --");

      init_sim();
      reset_dut();
      check_name_version();
        
      // TC1: Single block message: "abc".
      tc1 = 512'h61626380000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000018;
      res1 = 160'ha9993e364706816aba3e25717850c26c9cd0d89d;
      single_block_test(tc1, res1);

      // TC2: Double block message.
      // "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq"
      tc2_1 = 512'h6162636462636465636465666465666765666768666768696768696A68696A6B696A6B6C6A6B6C6D6B6C6D6E6C6D6E6F6D6E6F706E6F70718000000000000000;
      res2_1 = 160'hf4286818c37b27ae0408f581846771484a566572;
      
      tc2_2 = 512'h000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001C0;
      res2_2 = 160'h84983e441c3bd26ebaae4aa1f95129e5e54670f1;
      double_block_test(tc2_1, res2_1, tc2_2, res2_2);
      
      display_test_result();
      $display("*** Simulation done. ***");
      $finish;
    end // sha1_test
endmodule // tb_sha1

//======================================================================
// EOF tb_sha1.v
//======================================================================