//======================================================================
//
// tb_modexp.v
// -----------
// Testbench modular exponentiation core.
//
//
// Author: Joachim Strombergson, Peter Magnusson
// 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_modexp();
//----------------------------------------------------------------
// Internal constant and parameter definitions.
//----------------------------------------------------------------
parameter DEBUG = 0;
localparam CLK_HALF_PERIOD = 1;
localparam CLK_PERIOD = 2 * CLK_HALF_PERIOD;
// The DUT address map.
localparam ADDR_NAME0 = 8'h00;
localparam ADDR_NAME1 = 8'h01;
localparam ADDR_VERSION = 8'h02;
localparam ADDR_CTRL = 8'h08;
localparam CTRL_INIT_BIT = 0;
localparam CTRL_NEXT_BIT = 1;
//----------------------------------------------------------------
// 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("");
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
//----------------------------------------------------------------
// 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("*** 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
//----------------------------------------------------------------
// 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("*** Reading 0x%08x from 0x%02x.", read_data, address);
$display("");
end
end
endtask // read_word
//----------------------------------------------------------------
// 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();
display_test_results();
$display("");
$display("*** modexp simulation done. ***");
$finish;
end // main
endmodule // tb_modexp
//======================================================================
// EOF tb_modexp.v
//======================================================================
