//======================================================================
//
// tb_sha3.v
// -----------------------------
// Testbench for the SHA-3 core.
//
// Authors: Pavel Shatov, Joachim Strombergson, Pernd Paysan
// Copyright (c) 2015, 2017 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.
//
//======================================================================

module tb_sha3();


   //----------------------------------------------------------------
   // Hashes of empty messages
   //----------------------------------------------------------------
   localparam	[511:0]	SHA3_224_EMPTY_MSG =
	    {	224'h6b4e03423667dbb73b6e15454f0eb1abd4597f9a1b078e3f5b5a6bc7,
		{512-224{1'bX}}};

   localparam	[511:0]	SHA3_256_EMPTY_MSG =
	    {	256'ha7ffc6f8bf1ed76651c14756a061d662f580ff4de43b49fa82d80a4b80f8434a,
		{512-256{1'bX}}};
   
   localparam	[511:0]	SHA3_384_EMPTY_MSG =
	    {	384'h0c63a75b845e4f7d01107d852e4c2485c51a50aaaa94fc61995e71bbee983a2ac3713831264adb47fb6bd1e058d5f004,
		{512-384{1'bX}}};

   localparam	[511:0]	SHA3_512_EMPTY_MSG =
	    {	512'ha69f73cca23a9ac5c8b567dc185a756e97c982164fe25859e0d1dcc1475c80a615b2123af1f5f94c11e3e9402c3ac558f500199d95b6d3e301758586281dcd26};

   /*
    * The "short" message is the "abc" string (0x616263):
    *
    * https://www.di-mgt.com.au/sha_testvectors.html
    *
    */
   localparam	[511:0]	SHA3_224_SHORT_MSG =
	    {	224'he642824c3f8cf24ad09234ee7d3c766fc9a3a5168d0c94ad73b46fdf,
		{512-224{1'bX}}};

   localparam	[511:0]	SHA3_256_SHORT_MSG =
	    {	256'h3a985da74fe225b2045c172d6bd390bd855f086e3e9d525b46bfe24511431532,
		{512-256{1'bX}}};

   localparam	[511:0]	SHA3_384_SHORT_MSG =
	    {	384'hec01498288516fc926459f58e2c6ad8df9b473cb0fc08c2596da7cf0e49be4b298d88cea927ac7f539f1edf228376d25,
		{512-384{1'bX}}};

   localparam	[511:0]	SHA3_512_SHORT_MSG =
	    {	512'hb751850b1a57168a5693cd924b6b096e08f621827444f70d884f5d0240d2712e10e116e9192af3c91a7ec57647e3934057340b4cf408d5a56592f8274eec53f0};

   /*
    * The "long" message is the 1600-bit string 0xA3...A3 taken from:
    * https://csrc.nist.gov/Projects/Cryptographic-Standards-and-Guidelines/example-values
    *
    */

   localparam	[511:0]	SHA3_224_LONG_MSG =
	   {	224'h9376816ABA503F72F96CE7EB65AC095DEEE3BE4BF9BBC2A1CB7E11E0,
		{512-224{1'bX}}};

   localparam	[511:0]	SHA3_256_LONG_MSG =
	   {	256'h79F38ADEC5C20307A98EF76E8324AFBFD46CFD81B22E3973C65FA1BD9DE31787,
		{512-256{1'bX}}};

   localparam	[511:0]	SHA3_384_LONG_MSG =
	   {	384'h1881DE2CA7E41EF95DC4732B8F5F002B189CC1E42B74168ED1732649CE1DBCDD76197A31FD55EE989F2D7050DD473E8F,
		{512-384{1'bX}}};

   localparam	[511:0]	SHA3_512_LONG_MSG =
	   {	512'hE76DFAD22084A8B1467FCF2FFA58361BEC7628EDF5F3FDC0E4805DC48CAEECA81B7C13C30ADF52A3659584739A2DF46BE589C51CA1A4A8416DF6545A1CE8BA00};

   /*
    * Sponge Parameters
    *
    */
`define SHA3_224_BLOCK_BITS	1152
`define SHA3_256_BLOCK_BITS	1088
`define SHA3_384_BLOCK_BITS	 832
`define SHA3_512_BLOCK_BITS	 576

`define SHA3_224_OUTPUT_BITS	 224
`define SHA3_256_OUTPUT_BITS	 256
`define SHA3_384_OUTPUT_BITS	 384
`define SHA3_512_OUTPUT_BITS	 512
   
`define SHA3_224_MODE            0
`define SHA3_256_MODE            1
`define SHA3_384_MODE            2
`define SHA3_512_MODE            3
   

   //----------------------------------------------------------------
   // Internal constant and parameter definitions.
   //----------------------------------------------------------------
   parameter CLK_HALF_PERIOD = 2;
   parameter CLK_PERIOD = 2 * CLK_HALF_PERIOD;


   //----------------------------------------------------------------
   // Register and Wire declarations.
   //----------------------------------------------------------------
   reg				tb_clk;
   reg				tb_rst_n;
   reg				tb_we;
   reg [ 6:0] 			tb_addr;
   reg [31:0] 			tb_wr_data;
   reg				tb_dut_init;
   reg				tb_dut_next;
   reg [1:0] 			tb_dut_mode;
   wire [31:0] 			tb_rd_data;
   wire				tb_rdy;
   
   integer 			i, j;
   integer 			num_err;
   integer 			total_bits;
   integer 			block_words, output_words;
   
   reg [511:0] 			hash_shreg;		// output
   reg [31: 0] 			hash_word;		// current output word
   
   reg				mismatch;		// error flag


   //----------------------------------------------------------------
   // Device Under Test.
   //----------------------------------------------------------------
   sha3 dut
     (
      .clk		(tb_clk),
      .nreset	        (tb_rst_n),
      .w		(tb_we),
      .addr		(tb_addr),
      .din		(tb_wr_data),
      .dout		(tb_rd_data),
      .init		(tb_dut_init),
      .next		(tb_dut_next),
      .mode             (tb_dut_mode),
      .ready	        (tb_rdy)
      );


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

   //----------------------------------------------------------------
   // reset_dut()
   //
   // Toggles reset to force the DUT into a well defined state.
   //----------------------------------------------------------------
   task reset_dut;
      begin
	 $display("*** Toggling reset...");
	 tb_rst_n = 0;
	 #(4 * CLK_HALF_PERIOD);
	 tb_rst_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
	 tb_clk		= 0;
	 tb_rst_n	= 0;
	 tb_we		= 0;
	 tb_addr	= 7'd0;
	 tb_wr_data	= 32'h0;
	 tb_dut_init    = 0;
	 tb_dut_next    = 0;
	 tb_dut_mode    = 2'b0;
      end
   endtask // init_sim()


   //----------------------------------------------------------------
   // test_empty_message()
   //
   // The first pritimive test that verifies what happens with an
   // empty input message.
   //----------------------------------------------------------------
   task test_empty_message;
      
      input	[511:0]	correct_hash;	// known-good hash
      input integer	block_size;	// block length (bits)
      input integer	output_size;	// output length (bits)
      input integer     mode;
      
      begin

	 $display("*** Testing %0d-bit hash (%0d-bit block)...", output_size, block_size);

	 // number of words in block and output
	 block_words = block_size >> 5;		// block_words = block_length / 32
	 output_words = output_size >> 5;	// output_words = output_length / 32
	 
	 // wait for some time
	 #(4*CLK_PERIOD);

	 /*
	  * Note, that we must wipe entire block buffer, because
	  * it may contain leftovers from previous calculations!
	  * We wipe the registers and apply padding at the same time.
	  *
	  */
	 
	 for (i=0; i<50; i=i+1) begin
	    case (i)
	      0:		tb_wr_data = 32'h06000000;		// ...0001 | 10
	      block_words-1:	tb_wr_data = 32'h00000080;		//	1000...
	      default:		tb_wr_data = 32'h00000000;		
	    endcase
	    tb_addr = {1'b0, i[5:0]};	// increment address
	    tb_we = 1;			// enable writing
	    tb_dut_mode = mode;
	    #(CLK_PERIOD);
	 end

	 tb_addr = 'bX;
	 tb_we = 0;

	 /* run one absord-squeeze cycle */
	 sha3_sponge_pump_init();
	 
	 // reset error counter
	 mismatch = 0;
	 
	 // save the expected result
	 hash_shreg = correct_hash;
	 
	 // now read and compare
	 for (i=0; i<output_words; i=i+1) begin
	    
	    tb_addr = {1'b1, i[5:0]};
	    #(CLK_PERIOD);
	    
	    hash_word = tb_rd_data;
	    
	    $display("    *** hash_word[%0d]: reference = %08x, calculated = %08x",
		     i, hash_shreg[511-:32], hash_word);
	    
	    // compare
	    if (hash_shreg[511-:32] !== hash_word) begin
	       mismatch = 1;
	       num_err = num_err + 1;
	    end
	    
	    hash_shreg = {hash_shreg[511-32:0], {32{1'bX}}};
	 end			
	 
	 if (mismatch) $display("    *** Test failed.");
	 else          $display("    *** Test passed.");
	 
      end

   endtask // test_empty_message


   //----------------------------------------------------------------
   // test_short_message()
   //
   // The second simple test that verifies what happens with an
   // input message, that fits into just one block.
   //----------------------------------------------------------------
   task test_short_message;
      
      input	[511:0]	correct_hash;	// known-good hash
      input integer	block_size;	// block length (bits)
      input integer	output_size;	// output length (bits)
      input integer     mode;
      
      begin

	 $display("*** Testing %0d-bit hash (%0d-bit block)...", output_size, block_size);

	 // number of words in block and output
	 block_words = block_size >> 5;	// block_words = block_length / 32
	 output_words = output_size >> 5;	// output_words = output_length / 32
	 
	 // wait for some time
	 #(4*CLK_PERIOD);

	 /*
	  * Note, that we must wipe entire internal state, because
	  * it may contain leftovers from previous calculations!
	  * We wipe the internal state, fill in the message (0x616263)
	  * and apply padding all at once.
	  *
	  */
	 
	 for (i=0; i<50; i=i+1) begin
	    case (i)
	      0:		tb_wr_data = 32'h61626306;		// ...0001 | 10 | 'cba'
	      block_words-1:	tb_wr_data = 32'h00000080;		//	1000...
	      default:		tb_wr_data = 32'h00000000;							
	    endcase
	    tb_addr = {1'b0, i[5:0]};	// increment address
	    tb_we = 1;						// enable writing
	    tb_dut_mode = mode;
	    #(CLK_PERIOD);
	 end

	 tb_addr = 'bX;
	 tb_we = 0;

	 /* run one absord-squeeze cycle */
	 sha3_sponge_pump_init();
	 
	 // reset error counter
	 mismatch = 0;
	 
	 // save the expected result
	 hash_shreg = correct_hash;
	 
	 // now read and compare
	 for (i=0; i<output_words; i=i+1) begin
	    
	    tb_addr = {1'b1, i[5:0]};
	    #(CLK_PERIOD);
	    
	    hash_word = tb_rd_data;
	    
	    $display("    *** hash_word[%0d]: reference = %08x, calculated = %08x",
		     i, hash_shreg[511-:32], hash_word);
	    
	    // compare
	    if (hash_shreg[511-:32] !== hash_word) begin
	       mismatch = 1;
	       num_err = num_err + 1;
	    end
	    
	    hash_shreg = {hash_shreg[511-32:0], {32{1'bX}}};
	 end			
	 
	 if (mismatch) $display("    *** Test failed.");
	 else          $display("    *** Test passed.");
	 
      end

   endtask // test_short_message


   //----------------------------------------------------------------
   // test_long_message()
   //
   // The second not so pritimive test, that verifies what happens
   // when an input message spans more than one block.
   //----------------------------------------------------------------
   task test_long_message;
      
      input	[511:0]	correct_hash;
      input integer	block_size;
      input integer	output_size;
      input integer     mode;
      
      begin

	 $display("*** Testing %0d-bit hash (%0d-bit block)...", output_size, block_size);

	 // number of words in block and output
	 block_words = block_size >> 5;		// block_words = block_length / 32
	 output_words = output_size >> 5;	// output_words = output_length / 32
	 
	 // wait for some time
	 #(4*CLK_PERIOD);

	 /* start filling the first block */
	 total_bits = 1600;

	 /*
	  * note, that we must wipe entire internal state, because
	  * it may contain leftovers from previous calculations!
	  */

	 for (i=0; i<50; i=i+1) begin
	    tb_wr_data = (i < block_words) ? 32'hA3A3A3A3 : 32'h00000000;
	    tb_addr = {1'b0, i[5:0]};
	    tb_we = 1;
	    #(CLK_PERIOD);
	    if (i < block_words)
	      total_bits = total_bits - 32;
	 end

	 tb_addr = 'bX;
	 tb_we = 0;
	 tb_dut_mode = mode;

	 /* run one absord-squeeze cycle */
	 sha3_sponge_pump_init();

	 // process remaining bits
	 while (total_bits > -64) begin

	    /*
	     * note, that there's no need to fill entire bank now,
	     * because x ^ 0 == x
	     */

	    for (i=0; i<block_words; i=i+1) begin
	       
	       
	       if (total_bits > 0) begin
		  // message
		  tb_wr_data = 32'hA3A3A3A3;
		  tb_addr = {1'b0, i[5:0]};
		  tb_we = 1;
		  #(CLK_PERIOD);
		  total_bits = total_bits - 32;
	       end else if (total_bits == 0) begin
		  // padding
		  tb_wr_data = 32'h06000000;
		  tb_addr = {1'b0, i[5:0]};
		  tb_we = 1;
		  #(CLK_PERIOD);
		  total_bits = total_bits - 32;
	       end else if (i == (block_words-1)) begin
		  // more padding
		  tb_wr_data = 32'h00000080;
		  tb_addr = {1'b0, i[5:0]};
		  tb_we = 1;
		  #(CLK_PERIOD);
		  total_bits = total_bits - 32;
	       end else begin
		  // intermediate bytes
		  tb_wr_data = 32'h00000000;
		  tb_addr = {1'b0, i[5:0]};
		  tb_we = 1;
		  #(CLK_PERIOD);						
	       end
	       
	    end

	    tb_addr = 'bX;
	    tb_we = 0;

	    /* run one absord-squeeze cycle */
	    sha3_sponge_pump_next();

	 end
	 
	 // reset error counter
	 mismatch = 0;
	 
	 // save the expected result
	 hash_shreg = correct_hash;
	 
	 // now read and compare
	 for (i=0; i<output_words; i=i+1) begin
	    
	    tb_addr = {1'b1, i[5:0]};
	    #(CLK_PERIOD);
	    
	    hash_word = tb_rd_data;
	    
	    $display("    *** hash_word[%0d]: reference = %08x, calculated = %08x",
		     i, hash_shreg[511-:32], hash_word);
	    
	    // compare
	    if (hash_shreg[511-:32] !== hash_word) begin
	       mismatch = 1;
	       num_err = num_err + 1;
	    end
	    
	    hash_shreg = {hash_shreg[511-32:0], {32{1'bX}}};
	 end			
	 
	 if (mismatch) $display("    *** Test failed.");
	 else          $display("    *** Test passed.");
	 
      end

   endtask // test_long_message


   //----------------------------------------------------------------
   // sha3_sponge_pump_init;
   //
   // Make the "sponge" absord input data and then wait for output
   // data to be "squeezed out".
   //----------------------------------------------------------------
   task sha3_sponge_pump_init;
      
      begin : sha3_sponge_pump_init_task
	 
	 reg	poll_rdy;		// flag to keep waiting while the DUT is busy

	 // start operation
	 tb_dut_init = 1;
	 #(CLK_PERIOD);
	 tb_dut_init = 0;
	 
	 // poll ready output until the operation is finished
	 poll_rdy = 1;
	 while (poll_rdy) begin
	    #(CLK_PERIOD);
	    poll_rdy = !tb_rdy;
	 end
	 
      end
      
   endtask // sha3_sponge_pump


   //----------------------------------------------------------------
   // sha3_sponge_pump_next;
   //
   // Make the "sponge" absord input data and then wait for output
   // data to be "squeezed out".
   //----------------------------------------------------------------
   task sha3_sponge_pump_next;
      
      begin : sha3_sponge_pump_next_task
	 
	 reg	poll_rdy;		// flag to keep waiting while the DUT is busy

	 // start operation
	 tb_dut_next = 1;
	 #(CLK_PERIOD);
	 tb_dut_next = 0;
	 
	 // poll ready output until the operation is finished
	 poll_rdy = 1;
	 while (poll_rdy) begin
	    #(CLK_PERIOD);
	    poll_rdy = !tb_rdy;
	 end
	 
      end
      
   endtask // sha3_sponge_pump


   //----------------------------------------------------------------
   // sha3_test
   // The main test functionality.
   //----------------------------------------------------------------
   initial
      
     begin : sha3_test
	$display("*** Testbench for sha3.v started.");

	num_err = 0;

	init_sim();
	reset_dut();
	
	test_empty_message(SHA3_224_EMPTY_MSG, `SHA3_224_BLOCK_BITS, `SHA3_224_OUTPUT_BITS, `SHA3_224_MODE);
	test_empty_message(SHA3_256_EMPTY_MSG, `SHA3_256_BLOCK_BITS, `SHA3_256_OUTPUT_BITS, `SHA3_256_MODE);
	test_empty_message(SHA3_384_EMPTY_MSG, `SHA3_384_BLOCK_BITS, `SHA3_384_OUTPUT_BITS, `SHA3_384_MODE);
	test_empty_message(SHA3_512_EMPTY_MSG, `SHA3_512_BLOCK_BITS, `SHA3_512_OUTPUT_BITS, `SHA3_512_MODE);
	
	test_short_message(SHA3_224_SHORT_MSG, `SHA3_224_BLOCK_BITS, `SHA3_224_OUTPUT_BITS, `SHA3_224_MODE);
	test_short_message(SHA3_256_SHORT_MSG, `SHA3_256_BLOCK_BITS, `SHA3_256_OUTPUT_BITS, `SHA3_256_MODE);
	test_short_message(SHA3_384_SHORT_MSG, `SHA3_384_BLOCK_BITS, `SHA3_384_OUTPUT_BITS, `SHA3_384_MODE);
	test_short_message(SHA3_512_SHORT_MSG, `SHA3_512_BLOCK_BITS, `SHA3_512_OUTPUT_BITS, `SHA3_512_MODE);

	test_long_message(SHA3_224_LONG_MSG, `SHA3_224_BLOCK_BITS, `SHA3_224_OUTPUT_BITS, `SHA3_224_MODE);
	test_long_message(SHA3_256_LONG_MSG, `SHA3_256_BLOCK_BITS, `SHA3_256_OUTPUT_BITS, `SHA3_256_MODE);
	test_long_message(SHA3_384_LONG_MSG, `SHA3_384_BLOCK_BITS, `SHA3_384_OUTPUT_BITS, `SHA3_384_MODE);
	test_long_message(SHA3_512_LONG_MSG, `SHA3_512_BLOCK_BITS, `SHA3_512_OUTPUT_BITS, `SHA3_512_MODE);

	$display("*** Testbench for sha3.v done.");
	
	if (num_err == 0)
	  $display("    *** All tests passed.");
	else
	  $display("    *** %0d tests not passed.", num_err);
	
	$finish;
	
     end // sha3_test
   
endmodule // tb_sha3

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