(1) Adding auto generated testbench for verilog. (2) Update of the test generator. (3) Update of the Makefile to run test generator.

2 files changed, 1486 insertions, 0 deletions

diff --git a/src/tb/tb_modexp_autogenerated.v b/src/tb/tb_modexp_autogenerated.v
new file mode 100644
index 0000000..65cbeef
--- /dev/null
+++ b/src/tb/tb_modexp_autogenerated.v
@@ -0,0 +1,1007 @@
+//======================================================================
+//
+// tb_modexp_autogenerated.v
+// -----------
+// Testbench modular exponentiation core.
+//
+//
+// Author: Joachim Strombergson, Peter Magnusson
+// Copyright (c) 2015, Assured AB
+// All rights reserved.
+//
+// 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/100ps
+
+
+//------------------------------------------------------------------
+// Test module.
+//------------------------------------------------------------------
+module tb_modexp_autogenerated();
+
+  //----------------------------------------------------------------
+  // Internal constant and parameter definitions.
+  //----------------------------------------------------------------
+  parameter DEBUG = 1;
+
+  localparam CLK_HALF_PERIOD = 1;
+  localparam CLK_PERIOD      = 2 * CLK_HALF_PERIOD;
+
+  // The DUT address map.
+  localparam GENERAL_PREFIX      = 4'h0;
+  localparam ADDR_NAME0          = 8'h00;
+  localparam ADDR_NAME1          = 8'h01;
+  localparam ADDR_VERSION        = 8'h02;
+
+  localparam ADDR_CTRL           = 8'h08;
+  localparam CTRL_START_BIT      = 0;
+
+  localparam ADDR_STATUS         = 8'h09;
+  localparam STATUS_READY_BIT    = 0;
+
+  localparam ADDR_MODULUS_LENGTH  = 8'h20;
+  localparam ADDR_MESSAGE_LENGTH  = 8'h21;
+  localparam ADDR_EXPONENT_LENGTH = 8'h22;
+
+  localparam MODULUS_PREFIX      = 4'h1;
+  localparam ADDR_MODULUS_START  = 8'h00;
+  localparam ADDR_MODULUS_END    = 8'hff;
+
+  localparam EXPONENT_PREFIX     = 4'h2;
+  localparam ADDR_EXPONENT_START = 8'h00;
+  localparam ADDR_EXPONENT_END   = 8'hff;
+
+  localparam MESSAGE_PREFIX      = 4'h3;
+  localparam MESSAGE_START       = 8'h00;
+  localparam MESSAGE_END         = 8'hff;
+
+  localparam RESULT_PREFIX       = 4'h4;
+  localparam RESULT_START        = 8'h00;
+  localparam RESULT_END          = 8'hff;
+
+
+  //----------------------------------------------------------------
+  // Register and Wire declarations.
+  //----------------------------------------------------------------
+  reg [31 : 0]  cycle_ctr;
+  reg [31 : 0]  error_ctr;
+  reg [31 : 0]  tc_ctr;
+
+  reg [31 : 0]  read_data;
+  reg [127 : 0] result_data;
+
+  reg           tb_clk;
+  reg           tb_reset_n;
+  reg           tb_cs;
+  reg           tb_we;
+  reg [11  : 0] tb_address;
+  reg [31 : 0]  tb_write_data;
+  wire [31 : 0] tb_read_data;
+  wire          tb_error;
+
+
+  //----------------------------------------------------------------
+  // Device Under Test.
+  //----------------------------------------------------------------
+  modexp 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)
+            );
+
+
+  //----------------------------------------------------------------
+  // clk_gen
+  //
+  // Always running clock generator process.
+  //----------------------------------------------------------------
+  always
+    begin : clk_gen
+      #CLK_HALF_PERIOD;
+      tb_clk = !tb_clk;
+    end // clk_gen
+
+
+  //----------------------------------------------------------------
+  // sys_monitor()
+  //
+  // An always running process that creates a cycle counter and
+  // conditionally displays information about the DUT.
+  //----------------------------------------------------------------
+  always
+    begin : sys_monitor
+      cycle_ctr = cycle_ctr + 1;
+
+      #(CLK_PERIOD);
+
+      if (DEBUG)
+        begin
+          dump_dut_state();
+        end
+    end
+
+
+  //----------------------------------------------------------------
+  // dump_dut_state()
+  //
+  // Dump the state of the dump when needed.
+  //----------------------------------------------------------------
+  task dump_dut_state();
+    begin
+      $display("cycle: 0x%016x", cycle_ctr);
+      $display("State of DUT");
+      $display("------------");
+      $display("Inputs and outputs:");
+      $display("cs   = 0x%01x, we = 0x%01x", tb_cs, tb_we);
+      $display("addr = 0x%08x, read_data = 0x%08x, write_data = 0x%08x",
+               tb_address, tb_read_data, tb_write_data);
+      $display("");
+
+      $display("State:");
+      $display("ready_reg = 0x%01x, start_reg = 0x%01x, start_new = 0x%01x, start_we = 0x%01x",
+               dut.ready_reg, dut.start_reg, dut.start_new, dut.start_we);
+      $display("residue_valid = 0x%01x", dut.residue_valid_reg);
+      $display("loop_counter_reg = 0x%08x", dut.loop_counter_reg);
+      $display("exponent_length_reg = 0x%02x, modulus_length_reg = 0x%02x",
+               dut.exponent_length_reg, dut.modulus_length_reg);
+      $display("length_reg = 0x%02x, length_m1_reg = 0x%02x",
+               dut.length_reg, dut.length_m1_reg);
+      $display("ctrl_reg = 0x%04x", dut.modexp_ctrl_reg);
+      $display("");
+    end
+  endtask // dump_dut_state
+
+
+  //----------------------------------------------------------------
+  // reset_dut()
+  //
+  // Toggle reset to put the DUT into a well known state.
+  //----------------------------------------------------------------
+  task reset_dut();
+    begin
+      $display("*** Toggle reset.");
+      tb_reset_n = 0;
+
+      #(2 * CLK_PERIOD);
+      tb_reset_n = 1;
+      $display("");
+    end
+  endtask // reset_dut
+
+
+  //----------------------------------------------------------------
+  // display_test_results()
+  //
+  // Display the accumulated test results.
+  //----------------------------------------------------------------
+  task display_test_results();
+    begin
+      if (error_ctr == 0)
+        begin
+          $display("*** All %02d test cases completed successfully", tc_ctr);
+        end
+      else
+        begin
+          $display("*** %02d tests completed - %02d test cases did not complete successfully.",
+                   tc_ctr, error_ctr);
+        end
+    end
+  endtask // display_test_results
+
+
+  //----------------------------------------------------------------
+  // init_sim()
+  //
+  // Initialize all counters and testbed functionality as well
+  // as setting the DUT inputs to defined values.
+  //----------------------------------------------------------------
+  task init_sim();
+    begin
+      cycle_ctr          = 0;
+      error_ctr          = 0;
+      tc_ctr             = 0;
+
+      tb_clk             = 0;
+      tb_reset_n         = 1;
+
+      tb_cs              = 0;
+      tb_we              = 0;
+      tb_address         = 8'h00;
+      tb_write_data      = 32'h00000000;
+    end
+  endtask // init_sim
+
+
+  //----------------------------------------------------------------
+  // 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 [11 : 0] address);
+    begin
+      tb_address = address;
+      tb_cs = 1;
+      tb_we = 0;
+      #(CLK_PERIOD);
+      read_data = tb_read_data;
+      tb_cs = 0;
+
+      if (DEBUG)
+        begin
+          $display("*** (read_word) 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 [11 : 0] address,
+                  input [31 : 0] word);
+    begin
+      if (DEBUG)
+        begin
+          $display("*** (write_word) Writing 0x%08x to 0x%02x.", word, address);
+          $display("");
+        end
+
+      tb_address = address;
+      tb_write_data = word;
+      tb_cs = 1;
+      tb_we = 1;
+      #(2 * CLK_PERIOD);
+      tb_cs = 0;
+      tb_we = 0;
+    end
+  endtask // write_word
+
+
+  //----------------------------------------------------------------
+  // wait_ready()
+  //
+  // Wait until the ready flag in the core is set.
+  //----------------------------------------------------------------
+  task wait_ready();
+    begin
+      while (tb_read_data != 32'h00000001)
+          read_word({GENERAL_PREFIX, ADDR_STATUS});
+
+      if (DEBUG)
+        $display("*** (wait_ready) Ready flag has been set.");
+    end
+  endtask // wait_ready
+
+
+  //----------------------------------------------------------------
+  // dump_message_mem()
+  //
+  // Dump the contents of the message memory.
+  //----------------------------------------------------------------
+  task dump_message_mem();
+    reg [8 : 0] i;
+    begin
+      $display("Contents of the message memory:");
+      for (i = 0 ; i < 256 ; i = i + 8)
+        begin
+          $display("message_mem[0x%02x .. 0x%02x] = 0x%08x 0x%08x 0x%08x 0x%08x  0x%08x 0x%08x 0x%08x 0x%08x",
+                   i[7 : 0], (i[7 : 0] + 8'h07),
+                   dut.message_mem.mem[(i[7 : 0] + 0)], dut.message_mem.mem[(i[7 : 0] + 1)],
+                   dut.message_mem.mem[(i[7 : 0] + 2)], dut.message_mem.mem[(i[7 : 0] + 3)],
+                   dut.message_mem.mem[(i[7 : 0] + 4)], dut.message_mem.mem[(i[7 : 0] + 5)],
+                   dut.message_mem.mem[(i[7 : 0] + 6)], dut.message_mem.mem[(i[7 : 0] + 7)],
+                   );
+        end
+      $display("");
+    end
+  endtask // dump_message_mem
+
+
+  //----------------------------------------------------------------
+  // dump_exponent_mem()
+  //
+  // Dump the contents of the exponent memory.
+  //----------------------------------------------------------------
+  task dump_exponent_mem();
+    reg [8 : 0] i;
+    begin
+      $display("Contents of the exponent memory:");
+      for (i = 0 ; i < 256 ; i = i + 8)
+        begin
+          $display("exponent_mem[0x%02x .. 0x%02x] = 0x%08x 0x%08x 0x%08x 0x%08x  0x%08x 0x%08x 0x%08x 0x%08x",
+                   i[7 : 0], (i[7 : 0] + 8'h07),
+                   dut.exponent_mem.mem[(i[7 : 0] + 0)], dut.exponent_mem.mem[(i[7 : 0] + 1)],
+                   dut.exponent_mem.mem[(i[7 : 0] + 2)], dut.exponent_mem.mem[(i[7 : 0] + 3)],
+                   dut.exponent_mem.mem[(i[7 : 0] + 4)], dut.exponent_mem.mem[(i[7 : 0] + 5)],
+                   dut.exponent_mem.mem[(i[7 : 0] + 6)], dut.exponent_mem.mem[(i[7 : 0] + 7)],
+                   );
+        end
+      $display("");
+    end
+  endtask // dump_exponent_mem
+
+
+  //----------------------------------------------------------------
+  // dump_modulus_mem()
+  //
+  // Dump the contents of the modulus memory.
+  //----------------------------------------------------------------
+  task dump_modulus_mem();
+    reg [8 : 0] i;
+    begin
+      $display("Contents of the modulus memory:");
+      for (i = 0 ; i < 256 ; i = i + 8)
+        begin
+          $display("modulus_mem[0x%02x .. 0x%02x] = 0x%08x 0x%08x 0x%08x 0x%08x  0x%08x 0x%08x 0x%08x 0x%08x",
+                   i[7 : 0], (i[7 : 0] + 8'h07),
+                   dut.modulus_mem.mem[(i[7 : 0] + 0)], dut.modulus_mem.mem[(i[7 : 0] + 1)],
+                   dut.modulus_mem.mem[(i[7 : 0] + 2)], dut.modulus_mem.mem[(i[7 : 0] + 3)],
+                   dut.modulus_mem.mem[(i[7 : 0] + 4)], dut.modulus_mem.mem[(i[7 : 0] + 5)],
+                   dut.modulus_mem.mem[(i[7 : 0] + 6)], dut.modulus_mem.mem[(i[7 : 0] + 7)],
+                   );
+        end
+      $display("");
+    end
+  endtask // dump_modulus_mem
+
+
+  //----------------------------------------------------------------
+  // dump_residue_mem()
+  //
+  // Dump the contents of the residue memory.
+  //----------------------------------------------------------------
+  task dump_residue_mem();
+    reg [8 : 0] i;
+    begin
+      $display("Contents of the residue memory:");
+      for (i = 0 ; i < 256 ; i = i + 8)
+        begin
+          $display("residue_mem[0x%02x .. 0x%02x] = 0x%08x 0x%08x 0x%08x 0x%08x  0x%08x 0x%08x 0x%08x 0x%08x",
+                   i[7 : 0], (i[7 : 0] + 8'h07),
+                   dut.residue_mem.mem[(i[7 : 0] + 0)], dut.residue_mem.mem[(i[7 : 0] + 1)],
+                   dut.residue_mem.mem[(i[7 : 0] + 2)], dut.residue_mem.mem[(i[7 : 0] + 3)],
+                   dut.residue_mem.mem[(i[7 : 0] + 4)], dut.residue_mem.mem[(i[7 : 0] + 5)],
+                   dut.residue_mem.mem[(i[7 : 0] + 6)], dut.residue_mem.mem[(i[7 : 0] + 7)],
+                   );
+        end
+      $display("");
+    end
+  endtask // dump_residue_mem
+
+
+  //----------------------------------------------------------------
+  // dump_result_mem()
+  //
+  // Dump the contents of the result memory.
+  //----------------------------------------------------------------
+  task dump_result_mem();
+    reg [8 : 0] i;
+    begin
+      $display("Contents of the result memory:");
+      for (i = 0 ; i < 256 ; i = i + 8)
+        begin
+          $display("result_mem[0x%02x .. 0x%02x] = 0x%08x 0x%08x 0x%08x 0x%08x  0x%08x 0x%08x 0x%08x 0x%08x",
+                   i[7 : 0], (i[7 : 0] + 8'h07),
+                   dut.result_mem.mem[(i[7 : 0] + 0)], dut.result_mem.mem[(i[7 : 0] + 1)],
+                   dut.result_mem.mem[(i[7 : 0] + 2)], dut.result_mem.mem[(i[7 : 0] + 3)],
+                   dut.result_mem.mem[(i[7 : 0] + 4)], dut.result_mem.mem[(i[7 : 0] + 5)],
+                   dut.result_mem.mem[(i[7 : 0] + 6)], dut.result_mem.mem[(i[7 : 0] + 7)],
+                   );
+        end
+      $display("");
+    end
+  endtask // dump_result_mem
+
+
+  //----------------------------------------------------------------
+  // dump_memories()
+  //
+  // Dump the contents of the memories in the dut.
+  //----------------------------------------------------------------
+  task dump_memories();
+    begin
+      dump_message_mem();
+      dump_exponent_mem();
+      dump_modulus_mem();
+      dump_residue_mem();
+      dump_result_mem();
+    end
+  endtask // dump_memories
+
+task autogenerated_BASIC_M4962768465676381896();
+reg [31 : 0] read_data;
+begin
+tc_ctr = tc_ctr + 1;
+$display("autogenerated_BASIC_M4962768465676381896");
+write_word({MESSAGE_PREFIX, 8'h00}, 32'h00000001);
+write_word({MESSAGE_PREFIX, 8'h01}, 32'h946473e1);
+write_word({EXPONENT_PREFIX, 8'h00}, 32'h00000001);
+write_word({EXPONENT_PREFIX, 8'h01}, 32'h0e85e74f);
+write_word({GENERAL_PREFIX, ADDR_EXPONENT_LENGTH}, 32'h00000002););
+write_word({MODULUS_PREFIX, 8'h00}, 32'h00000001);
+write_word({MODULUS_PREFIX, 8'h01}, 32'h70754797);
+write_word({GENERAL_PREFIX, ADDR_MODULUS_LENGTH}, 32'h00000002););
+dump_memories()
+write_word({GENERAL_PREFIX, ADDR_CTRL}, 32'h00000002);
+wait_ready();
+read_word({RESULT_PREFIX,8'h00});
+read_data = tb_read_data;
+if (read_data !== 32'h00000000))
+  begin
+    $display("Expected: 0x00000000, got 0x%08x", read_data);
+  end
+read_word({RESULT_PREFIX,8'h01});
+read_data = tb_read_data;
+if (read_data !== 32'h7761ed4f))
+  begin
+    $display("Expected: 0x7761ed4f, got 0x%08x", read_data);
+  end
+end
+endtask // autogenerated_BASIC_M4962768465676381896
+task autogenerated_BASIC_8982867242010371843();
+reg [31 : 0] read_data;
+begin
+tc_ctr = tc_ctr + 1;
+$display("autogenerated_BASIC_8982867242010371843");
+write_word({MESSAGE_PREFIX, 8'h00}, 32'h00000001);
+write_word({MESSAGE_PREFIX, 8'h01}, 32'h6eb4ac2d);
+write_word({EXPONENT_PREFIX, 8'h00}, 32'h00000001);
+write_word({EXPONENT_PREFIX, 8'h01}, 32'hbb200e41);
+write_word({GENERAL_PREFIX, ADDR_EXPONENT_LENGTH}, 32'h00000002););
+write_word({MODULUS_PREFIX, 8'h00}, 32'h00000001);
+write_word({MODULUS_PREFIX, 8'h01}, 32'h27347dc3);
+write_word({GENERAL_PREFIX, ADDR_MODULUS_LENGTH}, 32'h00000002););
+dump_memories()
+write_word({GENERAL_PREFIX, ADDR_CTRL}, 32'h00000002);
+wait_ready();
+read_word({RESULT_PREFIX,8'h00});
+read_data = tb_read_data;
+if (read_data !== 32'h00000000))
+  begin
+    $display("Expected: 0x00000000, got 0x%08x", read_data);
+  end
+read_word({RESULT_PREFIX,8'h01});
+read_data = tb_read_data;
+if (read_data !== 32'h87d16204))
+  begin
+    $display("Expected: 0x87d16204, got 0x%08x", read_data);
+  end
+end
+endtask // autogenerated_BASIC_8982867242010371843
+task autogenerated_BASIC_5090788032873075449();
+reg [31 : 0] read_data;
+begin
+tc_ctr = tc_ctr + 1;
+$display("autogenerated_BASIC_5090788032873075449");
+write_word({MESSAGE_PREFIX, 8'h00}, 32'h00000001);
+write_word({MESSAGE_PREFIX, 8'h01}, 32'h9e504a03);
+write_word({EXPONENT_PREFIX, 8'h00}, 32'h00000001);
+write_word({EXPONENT_PREFIX, 8'h01}, 32'h9bc057ef);
+write_word({GENERAL_PREFIX, ADDR_EXPONENT_LENGTH}, 32'h00000002););
+write_word({MODULUS_PREFIX, 8'h00}, 32'h00000001);
+write_word({MODULUS_PREFIX, 8'h01}, 32'hc8b53fe5);
+write_word({GENERAL_PREFIX, ADDR_MODULUS_LENGTH}, 32'h00000002););
+dump_memories()
+write_word({GENERAL_PREFIX, ADDR_CTRL}, 32'h00000002);
+wait_ready();
+read_word({RESULT_PREFIX,8'h00});
+read_data = tb_read_data;
+if (read_data !== 32'h00000001))
+  begin
+    $display("Expected: 0x00000001, got 0x%08x", read_data);
+  end
+read_word({RESULT_PREFIX,8'h01});
+read_data = tb_read_data;
+if (read_data !== 32'hc1a6494c))
+  begin
+    $display("Expected: 0xc1a6494c, got 0x%08x", read_data);
+  end
+end
+endtask // autogenerated_BASIC_5090788032873075449
+task autogenerated_BASIC_8448510918869952728();
+reg [31 : 0] read_data;
+begin
+tc_ctr = tc_ctr + 1;
+$display("autogenerated_BASIC_8448510918869952728");
+write_word({MESSAGE_PREFIX, 8'h00}, 32'h00000001);
+write_word({MESSAGE_PREFIX, 8'h01}, 32'h73f7b309);
+write_word({EXPONENT_PREFIX, 8'h00}, 32'h00000001);
+write_word({EXPONENT_PREFIX, 8'h01}, 32'h91c10f7f);
+write_word({GENERAL_PREFIX, ADDR_EXPONENT_LENGTH}, 32'h00000002););
+write_word({MODULUS_PREFIX, 8'h00}, 32'h00000001);
+write_word({MODULUS_PREFIX, 8'h01}, 32'h4be322c9);
+write_word({GENERAL_PREFIX, ADDR_MODULUS_LENGTH}, 32'h00000002););
+dump_memories()
+write_word({GENERAL_PREFIX, ADDR_CTRL}, 32'h00000002);
+wait_ready();
+read_word({RESULT_PREFIX,8'h00});
+read_data = tb_read_data;
+if (read_data !== 32'h00000000))
+  begin
+    $display("Expected: 0x00000000, got 0x%08x", read_data);
+  end
+read_word({RESULT_PREFIX,8'h01});
+read_data = tb_read_data;
+if (read_data !== 32'h9a155286))
+  begin
+    $display("Expected: 0x9a155286, got 0x%08x", read_data);
+  end
+end
+endtask // autogenerated_BASIC_8448510918869952728
+task autogenerated_BASIC_4036237668019554146();
+reg [31 : 0] read_data;
+begin
+tc_ctr = tc_ctr + 1;
+$display("autogenerated_BASIC_4036237668019554146");
+write_word({MESSAGE_PREFIX, 8'h00}, 32'h00000001);
+write_word({MESSAGE_PREFIX, 8'h01}, 32'hd0f3961d);
+write_word({EXPONENT_PREFIX, 8'h00}, 32'h00000001);
+write_word({EXPONENT_PREFIX, 8'h01}, 32'hcdbc9c9d);
+write_word({GENERAL_PREFIX, ADDR_EXPONENT_LENGTH}, 32'h00000002););
+write_word({MODULUS_PREFIX, 8'h00}, 32'h00000001);
+write_word({MODULUS_PREFIX, 8'h01}, 32'h30367d5b);
+write_word({GENERAL_PREFIX, ADDR_MODULUS_LENGTH}, 32'h00000002););
+dump_memories()
+write_word({GENERAL_PREFIX, ADDR_CTRL}, 32'h00000002);
+wait_ready();
+read_word({RESULT_PREFIX,8'h00});
+read_data = tb_read_data;
+if (read_data !== 32'h00000001))
+  begin
+    $display("Expected: 0x00000001, got 0x%08x", read_data);
+  end
+read_word({RESULT_PREFIX,8'h01});
+read_data = tb_read_data;
+if (read_data !== 32'h15a9c15d))
+  begin
+    $display("Expected: 0x15a9c15d, got 0x%08x", read_data);
+  end
+end
+endtask // autogenerated_BASIC_4036237668019554146
+task autogenerated_BASIC_M8925041444689012509();
+reg [31 : 0] read_data;
+begin
+tc_ctr = tc_ctr + 1;
+$display("autogenerated_BASIC_M8925041444689012509");
+write_word({MESSAGE_PREFIX, 8'h00}, 32'h00000001);
+write_word({MESSAGE_PREFIX, 8'h01}, 32'h34130e17);
+write_word({EXPONENT_PREFIX, 8'h00}, 32'h00000001);
+write_word({EXPONENT_PREFIX, 8'h01}, 32'hf45e52c9);
+write_word({GENERAL_PREFIX, ADDR_EXPONENT_LENGTH}, 32'h00000002););
+write_word({MODULUS_PREFIX, 8'h00}, 32'h00000001);
+write_word({MODULUS_PREFIX, 8'h01}, 32'h9cb5c68d);
+write_word({GENERAL_PREFIX, ADDR_MODULUS_LENGTH}, 32'h00000002););
+dump_memories()
+write_word({GENERAL_PREFIX, ADDR_CTRL}, 32'h00000002);
+wait_ready();
+read_word({RESULT_PREFIX,8'h00});
+read_data = tb_read_data;
+if (read_data !== 32'h00000000))
+  begin
+    $display("Expected: 0x00000000, got 0x%08x", read_data);
+  end
+read_word({RESULT_PREFIX,8'h01});
+read_data = tb_read_data;
+if (read_data !== 32'h7c129d37))
+  begin
+    $display("Expected: 0x7c129d37, got 0x%08x", read_data);
+  end
+end
+endtask // autogenerated_BASIC_M8925041444689012509
+task autogenerated_BASIC_M5713608137760059379();
+reg [31 : 0] read_data;
+begin
+tc_ctr = tc_ctr + 1;
+$display("autogenerated_BASIC_M5713608137760059379");
+write_word({MESSAGE_PREFIX, 8'h00}, 32'h00000001);
+write_word({MESSAGE_PREFIX, 8'h01}, 32'h77505dbd);
+write_word({EXPONENT_PREFIX, 8'h00}, 32'h00000001);
+write_word({EXPONENT_PREFIX, 8'h01}, 32'hdb808627);
+write_word({GENERAL_PREFIX, ADDR_EXPONENT_LENGTH}, 32'h00000002););
+write_word({MODULUS_PREFIX, 8'h00}, 32'h00000001);
+write_word({MODULUS_PREFIX, 8'h01}, 32'had1fed09);
+write_word({GENERAL_PREFIX, ADDR_MODULUS_LENGTH}, 32'h00000002););
+dump_memories()
+write_word({GENERAL_PREFIX, ADDR_CTRL}, 32'h00000002);
+wait_ready();
+read_word({RESULT_PREFIX,8'h00});
+read_data = tb_read_data;
+if (read_data !== 32'h00000001))
+  begin
+    $display("Expected: 0x00000001, got 0x%08x", read_data);
+  end
+read_word({RESULT_PREFIX,8'h01});
+read_data = tb_read_data;
+if (read_data !== 32'h842cd733))
+  begin
+    $display("Expected: 0x842cd733, got 0x%08x", read_data);
+  end
+end
+endtask // autogenerated_BASIC_M5713608137760059379
+task autogenerated_BASIC_6816968587684568101();
+reg [31 : 0] read_data;
+begin
+tc_ctr = tc_ctr + 1;
+$display("autogenerated_BASIC_6816968587684568101");
+write_word({MESSAGE_PREFIX, 8'h00}, 32'h00000001);
+write_word({MESSAGE_PREFIX, 8'h01}, 32'h3272b6ef);
+write_word({EXPONENT_PREFIX, 8'h00}, 32'h00000001);
+write_word({EXPONENT_PREFIX, 8'h01}, 32'h2cb6c09b);
+write_word({GENERAL_PREFIX, ADDR_EXPONENT_LENGTH}, 32'h00000002););
+write_word({MODULUS_PREFIX, 8'h00}, 32'h00000001);
+write_word({MODULUS_PREFIX, 8'h01}, 32'hefbc64fd);
+write_word({GENERAL_PREFIX, ADDR_MODULUS_LENGTH}, 32'h00000002););
+dump_memories()
+write_word({GENERAL_PREFIX, ADDR_CTRL}, 32'h00000002);
+wait_ready();
+read_word({RESULT_PREFIX,8'h00});
+read_data = tb_read_data;
+if (read_data !== 32'h00000001))
+  begin
+    $display("Expected: 0x00000001, got 0x%08x", read_data);
+  end
+read_word({RESULT_PREFIX,8'h01});
+read_data = tb_read_data;
+if (read_data !== 32'h59c3b603))
+  begin
+    $display("Expected: 0x59c3b603, got 0x%08x", read_data);
+  end
+end
+endtask // autogenerated_BASIC_6816968587684568101
+task autogenerated_BASIC_4168013900853404774();
+reg [31 : 0] read_data;
+begin
+tc_ctr = tc_ctr + 1;
+$display("autogenerated_BASIC_4168013900853404774");
+write_word({MESSAGE_PREFIX, 8'h00}, 32'h00000001);
+write_word({MESSAGE_PREFIX, 8'h01}, 32'h3c20bbcf);
+write_word({EXPONENT_PREFIX, 8'h00}, 32'h00000001);
+write_word({EXPONENT_PREFIX, 8'h01}, 32'ha495d8ab);
+write_word({GENERAL_PREFIX, ADDR_EXPONENT_LENGTH}, 32'h00000002););
+write_word({MODULUS_PREFIX, 8'h00}, 32'h00000001);
+write_word({MODULUS_PREFIX, 8'h01}, 32'h75ddb9ef);
+write_word({GENERAL_PREFIX, ADDR_MODULUS_LENGTH}, 32'h00000002););
+dump_memories()
+write_word({GENERAL_PREFIX, ADDR_CTRL}, 32'h00000002);
+wait_ready();
+read_word({RESULT_PREFIX,8'h00});
+read_data = tb_read_data;
+if (read_data !== 32'h00000001))
+  begin
+    $display("Expected: 0x00000001, got 0x%08x", read_data);
+  end
+read_word({RESULT_PREFIX,8'h01});
+read_data = tb_read_data;
+if (read_data !== 32'h1413eac7))
+  begin
+    $display("Expected: 0x1413eac7, got 0x%08x", read_data);
+  end
+end
+endtask // autogenerated_BASIC_4168013900853404774
+task autogenerated_BASIC_M8394821325674331878();
+reg [31 : 0] read_data;
+begin
+tc_ctr = tc_ctr + 1;
+$display("autogenerated_BASIC_M8394821325674331878");
+write_word({MESSAGE_PREFIX, 8'h00}, 32'h00000001);
+write_word({MESSAGE_PREFIX, 8'h01}, 32'h93d3d0d3);
+write_word({EXPONENT_PREFIX, 8'h00}, 32'h00000001);
+write_word({EXPONENT_PREFIX, 8'h01}, 32'h43c2dfef);
+write_word({GENERAL_PREFIX, ADDR_EXPONENT_LENGTH}, 32'h00000002););
+write_word({MODULUS_PREFIX, 8'h00}, 32'h00000001);
+write_word({MODULUS_PREFIX, 8'h01}, 32'h7443cbf1);
+write_word({GENERAL_PREFIX, ADDR_MODULUS_LENGTH}, 32'h00000002););
+dump_memories()
+write_word({GENERAL_PREFIX, ADDR_CTRL}, 32'h00000002);
+wait_ready();
+read_word({RESULT_PREFIX,8'h00});
+read_data = tb_read_data;
+if (read_data !== 32'h00000000))
+  begin
+    $display("Expected: 0x00000000, got 0x%08x", read_data);
+  end
+read_word({RESULT_PREFIX,8'h01});
+read_data = tb_read_data;
+if (read_data !== 32'hc2eda7c3))
+  begin
+    $display("Expected: 0xc2eda7c3, got 0x%08x", read_data);
+  end
+end
+endtask // autogenerated_BASIC_M8394821325674331878
+task autogenerated_BASIC_M2919828800172604435();
+reg [31 : 0] read_data;
+begin
+tc_ctr = tc_ctr + 1;
+$display("autogenerated_BASIC_M2919828800172604435");
+write_word({MESSAGE_PREFIX, 8'h00}, 32'h3d746ec5);
+write_word({EXPONENT_PREFIX, 8'h00}, 32'h3f7ea6d5);
+write_word({GENERAL_PREFIX, ADDR_EXPONENT_LENGTH}, 32'h00000001););
+write_word({MODULUS_PREFIX, 8'h00}, 32'h29b6675f);
+write_word({GENERAL_PREFIX, ADDR_MODULUS_LENGTH}, 32'h00000001););
+dump_memories()
+write_word({GENERAL_PREFIX, ADDR_CTRL}, 32'h00000001);
+wait_ready();
+read_word({RESULT_PREFIX,8'h00});
+read_data = tb_read_data;
+if (read_data !== 32'h040c43d8))
+  begin
+    $display("Expected: 0x040c43d8, got 0x%08x", read_data);
+  end
+end
+endtask // autogenerated_BASIC_M2919828800172604435
+task autogenerated_BASIC_4770912732078070597();
+reg [31 : 0] read_data;
+begin
+tc_ctr = tc_ctr + 1;
+$display("autogenerated_BASIC_4770912732078070597");
+write_word({MESSAGE_PREFIX, 8'h00}, 32'h200c0f45);
+write_word({EXPONENT_PREFIX, 8'h00}, 32'h24774bab);
+write_word({GENERAL_PREFIX, ADDR_EXPONENT_LENGTH}, 32'h00000001););
+write_word({MODULUS_PREFIX, 8'h00}, 32'h234ca073);
+write_word({GENERAL_PREFIX, ADDR_MODULUS_LENGTH}, 32'h00000001););
+dump_memories()
+write_word({GENERAL_PREFIX, ADDR_CTRL}, 32'h00000001);
+wait_ready();
+read_word({RESULT_PREFIX,8'h00});
+read_data = tb_read_data;
+if (read_data !== 32'h14505436))
+  begin
+    $display("Expected: 0x14505436, got 0x%08x", read_data);
+  end
+end
+endtask // autogenerated_BASIC_4770912732078070597
+task autogenerated_BASIC_3593487472385409519();
+reg [31 : 0] read_data;
+begin
+tc_ctr = tc_ctr + 1;
+$display("autogenerated_BASIC_3593487472385409519");
+write_word({MESSAGE_PREFIX, 8'h00}, 32'h248819d1);
+write_word({EXPONENT_PREFIX, 8'h00}, 32'h2ad2b6ed);
+write_word({GENERAL_PREFIX, ADDR_EXPONENT_LENGTH}, 32'h00000001););
+write_word({MODULUS_PREFIX, 8'h00}, 32'h269cc6bf);
+write_word({GENERAL_PREFIX, ADDR_MODULUS_LENGTH}, 32'h00000001););
+dump_memories()
+write_word({GENERAL_PREFIX, ADDR_CTRL}, 32'h00000001);
+wait_ready();
+read_word({RESULT_PREFIX,8'h00});
+read_data = tb_read_data;
+if (read_data !== 32'h0f09d466))
+  begin
+    $display("Expected: 0x0f09d466, got 0x%08x", read_data);
+  end
+end
+endtask // autogenerated_BASIC_3593487472385409519
+task autogenerated_BASIC_4981749054780354961();
+reg [31 : 0] read_data;
+begin
+tc_ctr = tc_ctr + 1;
+$display("autogenerated_BASIC_4981749054780354961");
+write_word({MESSAGE_PREFIX, 8'h00}, 32'h27bec4e7);
+write_word({EXPONENT_PREFIX, 8'h00}, 32'h36fe540f);
+write_word({GENERAL_PREFIX, ADDR_EXPONENT_LENGTH}, 32'h00000001););
+write_word({MODULUS_PREFIX, 8'h00}, 32'h25a46d61);
+write_word({GENERAL_PREFIX, ADDR_MODULUS_LENGTH}, 32'h00000001););
+dump_memories()
+write_word({GENERAL_PREFIX, ADDR_CTRL}, 32'h00000001);
+wait_ready();
+read_word({RESULT_PREFIX,8'h00});
+read_data = tb_read_data;
+if (read_data !== 32'h0bab2269))
+  begin
+    $display("Expected: 0x0bab2269, got 0x%08x", read_data);
+  end
+end
+endtask // autogenerated_BASIC_4981749054780354961
+task autogenerated_BASIC_7702189670289360961();
+reg [31 : 0] read_data;
+begin
+tc_ctr = tc_ctr + 1;
+$display("autogenerated_BASIC_7702189670289360961");
+write_word({MESSAGE_PREFIX, 8'h00}, 32'h302def29);
+write_word({EXPONENT_PREFIX, 8'h00}, 32'h25b9c233);
+write_word({GENERAL_PREFIX, ADDR_EXPONENT_LENGTH}, 32'h00000001););
+write_word({MODULUS_PREFIX, 8'h00}, 32'h33af5461);
+write_word({GENERAL_PREFIX, ADDR_MODULUS_LENGTH}, 32'h00000001););
+dump_memories()
+write_word({GENERAL_PREFIX, ADDR_CTRL}, 32'h00000001);
+wait_ready();
+read_word({RESULT_PREFIX,8'h00});
+read_data = tb_read_data;
+if (read_data !== 32'h0229dc08))
+  begin
+    $display("Expected: 0x0229dc08, got 0x%08x", read_data);
+  end
+end
+endtask // autogenerated_BASIC_7702189670289360961
+task autogenerated_BASIC_M5169634701858105792();
+reg [31 : 0] read_data;
+begin
+tc_ctr = tc_ctr + 1;
+$display("autogenerated_BASIC_M5169634701858105792");
+write_word({MESSAGE_PREFIX, 8'h00}, 32'h240d8cf5);
+write_word({EXPONENT_PREFIX, 8'h00}, 32'h2a6a7381);
+write_word({GENERAL_PREFIX, ADDR_EXPONENT_LENGTH}, 32'h00000001););
+write_word({MODULUS_PREFIX, 8'h00}, 32'h3471d1e9);
+write_word({GENERAL_PREFIX, ADDR_MODULUS_LENGTH}, 32'h00000001););
+dump_memories()
+write_word({GENERAL_PREFIX, ADDR_CTRL}, 32'h00000001);
+wait_ready();
+read_word({RESULT_PREFIX,8'h00});
+read_data = tb_read_data;
+if (read_data !== 32'h244dec19))
+  begin
+    $display("Expected: 0x244dec19, got 0x%08x", read_data);
+  end
+end
+endtask // autogenerated_BASIC_M5169634701858105792
+task autogenerated_BASIC_6469444563916025786();
+reg [31 : 0] read_data;
+begin
+tc_ctr = tc_ctr + 1;
+$display("autogenerated_BASIC_6469444563916025786");
+write_word({MESSAGE_PREFIX, 8'h00}, 32'h3cc9270b);
+write_word({EXPONENT_PREFIX, 8'h00}, 32'h27858fdd);
+write_word({GENERAL_PREFIX, ADDR_EXPONENT_LENGTH}, 32'h00000001););
+write_word({MODULUS_PREFIX, 8'h00}, 32'h21e65001);
+write_word({GENERAL_PREFIX, ADDR_MODULUS_LENGTH}, 32'h00000001););
+dump_memories()
+write_word({GENERAL_PREFIX, ADDR_CTRL}, 32'h00000001);
+wait_ready();
+read_word({RESULT_PREFIX,8'h00});
+read_data = tb_read_data;
+if (read_data !== 32'h17200d8c))
+  begin
+    $display("Expected: 0x17200d8c, got 0x%08x", read_data);
+  end
+end
+endtask // autogenerated_BASIC_6469444563916025786
+task autogenerated_BASIC_M2453278165832221565();
+reg [31 : 0] read_data;
+begin
+tc_ctr = tc_ctr + 1;
+$display("autogenerated_BASIC_M2453278165832221565");
+write_word({MESSAGE_PREFIX, 8'h00}, 32'h30ca6ceb);
+write_word({EXPONENT_PREFIX, 8'h00}, 32'h212c387b);
+write_word({GENERAL_PREFIX, ADDR_EXPONENT_LENGTH}, 32'h00000001););
+write_word({MODULUS_PREFIX, 8'h00}, 32'h2e07a7bb);
+write_word({GENERAL_PREFIX, ADDR_MODULUS_LENGTH}, 32'h00000001););
+dump_memories()
+write_word({GENERAL_PREFIX, ADDR_CTRL}, 32'h00000001);
+wait_ready();
+read_word({RESULT_PREFIX,8'h00});
+read_data = tb_read_data;
+if (read_data !== 32'h0fc15a1f))
+  begin
+    $display("Expected: 0x0fc15a1f, got 0x%08x", read_data);
+  end
+end
+endtask // autogenerated_BASIC_M2453278165832221565
+task autogenerated_BASIC_M1847183855567461116();
+reg [31 : 0] read_data;
+begin
+tc_ctr = tc_ctr + 1;
+$display("autogenerated_BASIC_M1847183855567461116");
+write_word({MESSAGE_PREFIX, 8'h00}, 32'h3d02c5a1);
+write_word({EXPONENT_PREFIX, 8'h00}, 32'h35f12b45);
+write_word({GENERAL_PREFIX, ADDR_EXPONENT_LENGTH}, 32'h00000001););
+write_word({MODULUS_PREFIX, 8'h00}, 32'h32f0b03f);
+write_word({GENERAL_PREFIX, ADDR_MODULUS_LENGTH}, 32'h00000001););
+dump_memories()
+write_word({GENERAL_PREFIX, ADDR_CTRL}, 32'h00000001);
+wait_ready();
+read_word({RESULT_PREFIX,8'h00});
+read_data = tb_read_data;
+if (read_data !== 32'h2340f96f))
+  begin
+    $display("Expected: 0x2340f96f, got 0x%08x", read_data);
+  end
+end
+endtask // autogenerated_BASIC_M1847183855567461116
+task autogenerated_BASIC_M7037130911981370263();
+reg [31 : 0] read_data;
+begin
+tc_ctr = tc_ctr + 1;
+$display("autogenerated_BASIC_M7037130911981370263");
+write_word({MESSAGE_PREFIX, 8'h00}, 32'h2692d1cd);
+write_word({EXPONENT_PREFIX, 8'h00}, 32'h3b21ef8d);
+write_word({GENERAL_PREFIX, ADDR_EXPONENT_LENGTH}, 32'h00000001););
+write_word({MODULUS_PREFIX, 8'h00}, 32'h2042c76d);
+write_word({GENERAL_PREFIX, ADDR_MODULUS_LENGTH}, 32'h00000001););
+dump_memories()
+write_word({GENERAL_PREFIX, ADDR_CTRL}, 32'h00000001);
+wait_ready();
+read_word({RESULT_PREFIX,8'h00});
+read_data = tb_read_data;
+if (read_data !== 32'h1b753aea))
+  begin
+    $display("Expected: 0x1b753aea, got 0x%08x", read_data);
+  end
+end
+endtask // autogenerated_BASIC_M7037130911981370263
+
+  //----------------------------------------------------------------
+  // main
+  //
+  // The main test functionality.
+  //----------------------------------------------------------------
+  initial
+    begin : main
+
+      $display("   -= Testbench for modexp started =-");
+      $display("    =================================");
+      $display("");
+
+      init_sim();
+      dump_dut_state();
+      reset_dut();
+      dump_dut_state();
+
+autogenerated_BASIC_M4962768465676381896();
+autogenerated_BASIC_8982867242010371843();
+autogenerated_BASIC_5090788032873075449();
+autogenerated_BASIC_8448510918869952728();
+autogenerated_BASIC_4036237668019554146();
+autogenerated_BASIC_M8925041444689012509();
+autogenerated_BASIC_M5713608137760059379();
+autogenerated_BASIC_6816968587684568101();
+autogenerated_BASIC_4168013900853404774();
+autogenerated_BASIC_M8394821325674331878();
+autogenerated_BASIC_M2919828800172604435();
+autogenerated_BASIC_4770912732078070597();
+autogenerated_BASIC_3593487472385409519();
+autogenerated_BASIC_4981749054780354961();
+autogenerated_BASIC_7702189670289360961();
+autogenerated_BASIC_M5169634701858105792();
+autogenerated_BASIC_6469444563916025786();
+autogenerated_BASIC_M2453278165832221565();
+autogenerated_BASIC_M1847183855567461116();
+autogenerated_BASIC_M7037130911981370263();
+
+      display_test_results();
+
+      $display("");
+      $display("*** modexp simulation done. ***");
+      $finish;
+    end // main
+endmodule // tb_modexp
+
+//======================================================================
+// EOF tb_modexp.v
+//======================================================================
diff --git a/src/tb/tb_modexp_autogenerated_template.v b/src/tb/tb_modexp_autogenerated_template.v
new file mode 100644
index 0000000..62ab7dc
--- /dev/null
+++ b/src/tb/tb_modexp_autogenerated_template.v
@@ -0,0 +1,479 @@
+//======================================================================
+//
+// tb_modexp_autogenerated.v
+// -----------
+// Testbench modular exponentiation core.
+//
+//
+// Author: Joachim Strombergson, Peter Magnusson
+// Copyright (c) 2015, Assured AB
+// All rights reserved.
+//
+// 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/100ps
+
+
+//------------------------------------------------------------------
+// Test module.
+//------------------------------------------------------------------
+module tb_modexp_autogenerated();
+
+  //----------------------------------------------------------------
+  // Internal constant and parameter definitions.
+  //----------------------------------------------------------------
+  parameter DEBUG = 1;
+
+  localparam CLK_HALF_PERIOD = 1;
+  localparam CLK_PERIOD      = 2 * CLK_HALF_PERIOD;
+
+  // The DUT address map.
+  localparam GENERAL_PREFIX      = 4'h0;
+  localparam ADDR_NAME0          = 8'h00;
+  localparam ADDR_NAME1          = 8'h01;
+  localparam ADDR_VERSION        = 8'h02;
+
+  localparam ADDR_CTRL           = 8'h08;
+  localparam CTRL_START_BIT      = 0;
+
+  localparam ADDR_STATUS         = 8'h09;
+  localparam STATUS_READY_BIT    = 0;
+
+  localparam ADDR_MODULUS_LENGTH  = 8'h20;
+  localparam ADDR_MESSAGE_LENGTH  = 8'h21;
+  localparam ADDR_EXPONENT_LENGTH = 8'h22;
+
+  localparam MODULUS_PREFIX      = 4'h1;
+  localparam ADDR_MODULUS_START  = 8'h00;
+  localparam ADDR_MODULUS_END    = 8'hff;
+
+  localparam EXPONENT_PREFIX     = 4'h2;
+  localparam ADDR_EXPONENT_START = 8'h00;
+  localparam ADDR_EXPONENT_END   = 8'hff;
+
+  localparam MESSAGE_PREFIX      = 4'h3;
+  localparam MESSAGE_START       = 8'h00;
+  localparam MESSAGE_END         = 8'hff;
+
+  localparam RESULT_PREFIX       = 4'h4;
+  localparam RESULT_START        = 8'h00;
+  localparam RESULT_END          = 8'hff;
+
+
+  //----------------------------------------------------------------
+  // Register and Wire declarations.
+  //----------------------------------------------------------------
+  reg [31 : 0]  cycle_ctr;
+  reg [31 : 0]  error_ctr;
+  reg [31 : 0]  tc_ctr;
+
+  reg [31 : 0]  read_data;
+  reg [127 : 0] result_data;
+
+  reg           tb_clk;
+  reg           tb_reset_n;
+  reg           tb_cs;
+  reg           tb_we;
+  reg [11  : 0] tb_address;
+  reg [31 : 0]  tb_write_data;
+  wire [31 : 0] tb_read_data;
+  wire          tb_error;
+
+
+  //----------------------------------------------------------------
+  // Device Under Test.
+  //----------------------------------------------------------------
+  modexp 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)
+            );
+
+
+  //----------------------------------------------------------------
+  // clk_gen
+  //
+  // Always running clock generator process.
+  //----------------------------------------------------------------
+  always
+    begin : clk_gen
+      #CLK_HALF_PERIOD;
+      tb_clk = !tb_clk;
+    end // clk_gen
+
+
+  //----------------------------------------------------------------
+  // sys_monitor()
+  //
+  // An always running process that creates a cycle counter and
+  // conditionally displays information about the DUT.
+  //----------------------------------------------------------------
+  always
+    begin : sys_monitor
+      cycle_ctr = cycle_ctr + 1;
+
+      #(CLK_PERIOD);
+
+      if (DEBUG)
+        begin
+          dump_dut_state();
+        end
+    end
+
+
+  //----------------------------------------------------------------
+  // dump_dut_state()
+  //
+  // Dump the state of the dump when needed.
+  //----------------------------------------------------------------
+  task dump_dut_state();
+    begin
+      $display("cycle: 0x%016x", cycle_ctr);
+      $display("State of DUT");
+      $display("------------");
+      $display("Inputs and outputs:");
+      $display("cs   = 0x%01x, we = 0x%01x", tb_cs, tb_we);
+      $display("addr = 0x%08x, read_data = 0x%08x, write_data = 0x%08x",
+               tb_address, tb_read_data, tb_write_data);
+      $display("");
+
+      $display("State:");
+      $display("ready_reg = 0x%01x, start_reg = 0x%01x, start_new = 0x%01x, start_we = 0x%01x",
+               dut.ready_reg, dut.start_reg, dut.start_new, dut.start_we);
+      $display("residue_valid = 0x%01x", dut.residue_valid_reg);
+      $display("loop_counter_reg = 0x%08x", dut.loop_counter_reg);
+      $display("exponent_length_reg = 0x%02x, modulus_length_reg = 0x%02x",
+               dut.exponent_length_reg, dut.modulus_length_reg);
+      $display("length_reg = 0x%02x, length_m1_reg = 0x%02x",
+               dut.length_reg, dut.length_m1_reg);
+      $display("ctrl_reg = 0x%04x", dut.modexp_ctrl_reg);
+      $display("");
+    end
+  endtask // dump_dut_state
+
+
+  //----------------------------------------------------------------
+  // reset_dut()
+  //
+  // Toggle reset to put the DUT into a well known state.
+  //----------------------------------------------------------------
+  task reset_dut();
+    begin
+      $display("*** Toggle reset.");
+      tb_reset_n = 0;
+
+      #(2 * CLK_PERIOD);
+      tb_reset_n = 1;
+      $display("");
+    end
+  endtask // reset_dut
+
+
+  //----------------------------------------------------------------
+  // display_test_results()
+  //
+  // Display the accumulated test results.
+  //----------------------------------------------------------------
+  task display_test_results();
+    begin
+      if (error_ctr == 0)
+        begin
+          $display("*** All %02d test cases completed successfully", tc_ctr);
+        end
+      else
+        begin
+          $display("*** %02d tests completed - %02d test cases did not complete successfully.",
+                   tc_ctr, error_ctr);
+        end
+    end
+  endtask // display_test_results
+
+
+  //----------------------------------------------------------------
+  // init_sim()
+  //
+  // Initialize all counters and testbed functionality as well
+  // as setting the DUT inputs to defined values.
+  //----------------------------------------------------------------
+  task init_sim();
+    begin
+      cycle_ctr          = 0;
+      error_ctr          = 0;
+      tc_ctr             = 0;
+
+      tb_clk             = 0;
+      tb_reset_n         = 1;
+
+      tb_cs              = 0;
+      tb_we              = 0;
+      tb_address         = 8'h00;
+      tb_write_data      = 32'h00000000;
+    end
+  endtask // init_sim
+
+
+  //----------------------------------------------------------------
+  // 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 [11 : 0] address);
+    begin
+      tb_address = address;
+      tb_cs = 1;
+      tb_we = 0;
+      #(CLK_PERIOD);
+      read_data = tb_read_data;
+      tb_cs = 0;
+
+      if (DEBUG)
+        begin
+          $display("*** (read_word) 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 [11 : 0] address,
+                  input [31 : 0] word);
+    begin
+      if (DEBUG)
+        begin
+          $display("*** (write_word) Writing 0x%08x to 0x%02x.", word, address);
+          $display("");
+        end
+
+      tb_address = address;
+      tb_write_data = word;
+      tb_cs = 1;
+      tb_we = 1;
+      #(2 * CLK_PERIOD);
+      tb_cs = 0;
+      tb_we = 0;
+    end
+  endtask // write_word
+
+
+  //----------------------------------------------------------------
+  // wait_ready()
+  //
+  // Wait until the ready flag in the core is set.
+  //----------------------------------------------------------------
+  task wait_ready();
+    begin
+      while (tb_read_data != 32'h00000001)
+          read_word({GENERAL_PREFIX, ADDR_STATUS});
+
+      if (DEBUG)
+        $display("*** (wait_ready) Ready flag has been set.");
+    end
+  endtask // wait_ready
+
+
+  //----------------------------------------------------------------
+  // dump_message_mem()
+  //
+  // Dump the contents of the message memory.
+  //----------------------------------------------------------------
+  task dump_message_mem();
+    reg [8 : 0] i;
+    begin
+      $display("Contents of the message memory:");
+      for (i = 0 ; i < 256 ; i = i + 8)
+        begin
+          $display("message_mem[0x%02x .. 0x%02x] = 0x%08x 0x%08x 0x%08x 0x%08x  0x%08x 0x%08x 0x%08x 0x%08x",
+                   i[7 : 0], (i[7 : 0] + 8'h07),
+                   dut.message_mem.mem[(i[7 : 0] + 0)], dut.message_mem.mem[(i[7 : 0] + 1)],
+                   dut.message_mem.mem[(i[7 : 0] + 2)], dut.message_mem.mem[(i[7 : 0] + 3)],
+                   dut.message_mem.mem[(i[7 : 0] + 4)], dut.message_mem.mem[(i[7 : 0] + 5)],
+                   dut.message_mem.mem[(i[7 : 0] + 6)], dut.message_mem.mem[(i[7 : 0] + 7)],
+                   );
+        end
+      $display("");
+    end
+  endtask // dump_message_mem
+
+
+  //----------------------------------------------------------------
+  // dump_exponent_mem()
+  //
+  // Dump the contents of the exponent memory.
+  //----------------------------------------------------------------
+  task dump_exponent_mem();
+    reg [8 : 0] i;
+    begin
+      $display("Contents of the exponent memory:");
+      for (i = 0 ; i < 256 ; i = i + 8)
+        begin
+          $display("exponent_mem[0x%02x .. 0x%02x] = 0x%08x 0x%08x 0x%08x 0x%08x  0x%08x 0x%08x 0x%08x 0x%08x",
+                   i[7 : 0], (i[7 : 0] + 8'h07),
+                   dut.exponent_mem.mem[(i[7 : 0] + 0)], dut.exponent_mem.mem[(i[7 : 0] + 1)],
+                   dut.exponent_mem.mem[(i[7 : 0] + 2)], dut.exponent_mem.mem[(i[7 : 0] + 3)],
+                   dut.exponent_mem.mem[(i[7 : 0] + 4)], dut.exponent_mem.mem[(i[7 : 0] + 5)],
+                   dut.exponent_mem.mem[(i[7 : 0] + 6)], dut.exponent_mem.mem[(i[7 : 0] + 7)],
+                   );
+        end
+      $display("");
+    end
+  endtask // dump_exponent_mem
+
+
+  //----------------------------------------------------------------
+  // dump_modulus_mem()
+  //
+  // Dump the contents of the modulus memory.
+  //----------------------------------------------------------------
+  task dump_modulus_mem();
+    reg [8 : 0] i;
+    begin
+      $display("Contents of the modulus memory:");
+      for (i = 0 ; i < 256 ; i = i + 8)
+        begin
+          $display("modulus_mem[0x%02x .. 0x%02x] = 0x%08x 0x%08x 0x%08x 0x%08x  0x%08x 0x%08x 0x%08x 0x%08x",
+                   i[7 : 0], (i[7 : 0] + 8'h07),
+                   dut.modulus_mem.mem[(i[7 : 0] + 0)], dut.modulus_mem.mem[(i[7 : 0] + 1)],
+                   dut.modulus_mem.mem[(i[7 : 0] + 2)], dut.modulus_mem.mem[(i[7 : 0] + 3)],
+                   dut.modulus_mem.mem[(i[7 : 0] + 4)], dut.modulus_mem.mem[(i[7 : 0] + 5)],
+                   dut.modulus_mem.mem[(i[7 : 0] + 6)], dut.modulus_mem.mem[(i[7 : 0] + 7)],
+                   );
+        end
+      $display("");
+    end
+  endtask // dump_modulus_mem
+
+
+  //----------------------------------------------------------------
+  // dump_residue_mem()
+  //
+  // Dump the contents of the residue memory.
+  //----------------------------------------------------------------
+  task dump_residue_mem();
+    reg [8 : 0] i;
+    begin
+      $display("Contents of the residue memory:");
+      for (i = 0 ; i < 256 ; i = i + 8)
+        begin
+          $display("residue_mem[0x%02x .. 0x%02x] = 0x%08x 0x%08x 0x%08x 0x%08x  0x%08x 0x%08x 0x%08x 0x%08x",
+                   i[7 : 0], (i[7 : 0] + 8'h07),
+                   dut.residue_mem.mem[(i[7 : 0] + 0)], dut.residue_mem.mem[(i[7 : 0] + 1)],
+                   dut.residue_mem.mem[(i[7 : 0] + 2)], dut.residue_mem.mem[(i[7 : 0] + 3)],
+                   dut.residue_mem.mem[(i[7 : 0] + 4)], dut.residue_mem.mem[(i[7 : 0] + 5)],
+                   dut.residue_mem.mem[(i[7 : 0] + 6)], dut.residue_mem.mem[(i[7 : 0] + 7)],
+                   );
+        end
+      $display("");
+    end
+  endtask // dump_residue_mem
+
+
+  //----------------------------------------------------------------
+  // dump_result_mem()
+  //
+  // Dump the contents of the result memory.
+  //----------------------------------------------------------------
+  task dump_result_mem();
+    reg [8 : 0] i;
+    begin
+      $display("Contents of the result memory:");
+      for (i = 0 ; i < 256 ; i = i + 8)
+        begin
+          $display("result_mem[0x%02x .. 0x%02x] = 0x%08x 0x%08x 0x%08x 0x%08x  0x%08x 0x%08x 0x%08x 0x%08x",
+                   i[7 : 0], (i[7 : 0] + 8'h07),
+                   dut.result_mem.mem[(i[7 : 0] + 0)], dut.result_mem.mem[(i[7 : 0] + 1)],
+                   dut.result_mem.mem[(i[7 : 0] + 2)], dut.result_mem.mem[(i[7 : 0] + 3)],
+                   dut.result_mem.mem[(i[7 : 0] + 4)], dut.result_mem.mem[(i[7 : 0] + 5)],
+                   dut.result_mem.mem[(i[7 : 0] + 6)], dut.result_mem.mem[(i[7 : 0] + 7)],
+                   );
+        end
+      $display("");
+    end
+  endtask // dump_result_mem
+
+
+  //----------------------------------------------------------------
+  // dump_memories()
+  //
+  // Dump the contents of the memories in the dut.
+  //----------------------------------------------------------------
+  task dump_memories();
+    begin
+      dump_message_mem();
+      dump_exponent_mem();
+      dump_modulus_mem();
+      dump_residue_mem();
+      dump_result_mem();
+    end
+  endtask // dump_memories
+
+// ===TEMPLATE_HEADER_END===
+
+  //----------------------------------------------------------------
+  // main
+  //
+  // The main test functionality.
+  //----------------------------------------------------------------
+  initial
+    begin : main
+
+      $display("   -= Testbench for modexp started =-");
+      $display("    =================================");
+      $display("");
+
+      init_sim();
+      dump_dut_state();
+      reset_dut();
+      dump_dut_state();
+
+// ===TEMPLATE_CALL_TASKS===
+
+      display_test_results();
+
+      $display("");
+      $display("*** modexp simulation done. ***");
+      $finish;
+    end // main
+endmodule // tb_modexp
+
+//======================================================================
+// EOF tb_modexp.v
+//======================================================================