//======================================================================
//
// tb_factor.v
// -----------------------------------------------------------------------------
// Testbench for Montgomery factor calculation block.
//
// Authors: Pavel Shatov
//
// Copyright (c) 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.
//
//======================================================================
`timescale 1ns / 1ps
module tb_factor;
//
// Test Vectors
//
`include "modexp_fpga_model_vectors.v";
//
// Parameters
//
localparam NUM_WORDS_384 = 384 / 32;
//
// Clock (100 MHz)
//
reg clk = 1'b0;
always #5 clk = ~clk;
//
// Inputs
//
reg rst_n;
reg ena;
reg [ 3: 0] n_num_words;
//
// Outputs
//
wire rdy;
//
// Integers
//
integer w;
//
// BRAM Interfaces
//
wire [ 3: 0] core_n_addr;
wire [ 3: 0] core_f_addr;
wire [31: 0] core_n_data;
wire [31: 0] core_f_data_in;
wire core_f_wren;
reg [ 3: 0] tb_n_addr;
reg [ 3: 0] tb_f_addr;
reg [31:0] tb_n_data;
wire [31:0] tb_f_data;
reg tb_n_wren;
//
// BRAMs
//
bram_1rw_1ro_readfirst #(.MEM_WIDTH(32), .MEM_ADDR_BITS(4))
bram_n (.clk(clk),
.a_addr(tb_n_addr), .a_wr(tb_n_wren), .a_in(tb_n_data), .a_out(),
.b_addr(core_n_addr), .b_out(core_n_data));
bram_1rw_1ro_readfirst #(.MEM_WIDTH(32), .MEM_ADDR_BITS(4))
bram_f (.clk(clk),
.a_addr(core_f_addr), .a_wr(core_f_wren), .a_in(core_f_data_in), .a_out(),
.b_addr(tb_f_addr), .b_out(tb_f_data));
//
// UUT
//
modexpa7_factor #
(
.OPERAND_ADDR_WIDTH (4) // 32 * (2**4) = 512-bit operands
)
uut
(
.clk (clk),
.rst_n (rst_n),
.ena (ena),
.rdy (rdy),
.n_bram_addr (core_n_addr),
.f_bram_addr (core_f_addr),
.n_bram_out (core_n_data),
.f_bram_in (core_f_data_in),
.f_bram_wr (core_f_wren),
.n_num_words (n_num_words)
);
//
// Script
//
initial begin
rst_n = 1'b0;
ena = 1'b0;
#200;
rst_n = 1'b1;
#100;
test_factor_384(N_384);
end
//
// Test Tasks
//
task test_factor_384;
input [383:0] n;
reg [383:0] f;
reg [383:0] factor;
integer i;
begin
calc_factor_384(n, f); // calculate factor on-the-fly
// make sure, that the value matches the one saved in the include file
if (f !== FACTOR_384) begin
$display("ERROR: Calculated factor value differs from the one in the test vector!");
$finish;
end
n_num_words = 4'd11; // set number of words
write_memory_384(n); // fill memory
ena = 1; // start operation
#10; //
ena = 0; // clear flag
while (!rdy) #10; // wait for operation to complete
read_memory_384(factor); // get result from memory
$display(" calculated: %x", factor); //
$display(" expected: %x", f); //
// check calculated value
if (f === factor) begin
$display(" OK");
$display("SUCCESS: Test passed.");
end else begin
$display(" ERROR");
$display("FAILURE: Test not passed.");
end
end
endtask
task write_memory_384;
input [383:0] n;
reg [383:0] n_shreg;
begin
tb_n_wren = 1; // start filling memories
n_shreg = n; //
for (w=0; w<NUM_WORDS_384; w=w+1) begin // write all words
tb_n_addr = w[3:0]; // set addresses
tb_n_data = n_shreg[31:0]; //
n_shreg = {{32{1'bX}}, n_shreg[383:32]}; //
#10; // wait for 1 clock tick
end
tb_n_addr = {4{1'bX}}; // wipe addresses
tb_n_data = {32{1'bX}}; //
tb_n_wren = 0; // stop filling memories
end
endtask
task read_memory_384;
output [383:0] f;
reg [383:0] f_shreg;
begin
// read result word-by-word
for (w=0; w<NUM_WORDS_384; w=w+1) begin
tb_f_addr = w[3:0]; // set address
#10; // wait for 1 clock tick
f_shreg = {tb_f_data, f_shreg[383:32]}; // store data word
end
tb_f_addr = {4{1'bX}}; // wipe address
f = f_shreg; // return
end
endtask
task calc_factor_384;
input [383:0] n;
output [383:0] factor;
reg [383:0] f;
reg [384:0] f1;
reg [384:0] f2;
integer i;
begin
f = 384'd1;
for (i=0; i<768; i=i+1) begin
f1 = {f, 1'b0};
f2 = f1 - {1'b0, n};
f = (f1 >= {1'b0, n}) ? f2 : f1;
end
factor = f;
end
endtask
endmodule
//======================================================================
// End of file
//======================================================================
