//------------------------------------------------------------------------------
//
// tb_modular_multiplier.v
// -----------------------------------------------------------------------------
// Testbench for Curve25519 modular multiplier.
//
// Authors: Pavel Shatov
//
// Copyright (c) 2018, NORDUnet A/S
//
// 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_modular_multiplier;
//
// Test Vectors
//
localparam A1 = 256'h216936d3_cd6e53fe_c0a4e231_fdd6dc5c_692cc760_9525a7b2_c9562d60_8f25d51a; // GX
localparam B1 = 256'h66666666_66666666_66666666_66666666_66666666_66666666_66666666_66666658; // GY
localparam C1 = 256'h67875f0f_d78b7665_66ea4e8e_64abe37d_20f09f80_775152f5_6dde8ab3_a5b7dda3; // GT
localparam F = 256'hFFFFFFFF_FFFFFFFF_FFFFFFFF_FFFFFFFF_FFFFFFFF_FFFFFFFF_FFFFFFFF_FFFFFFFF; // FFF...F
//
// Core Parameters
//
localparam WORD_COUNTER_WIDTH = 3;
localparam OPERAND_NUM_WORDS = 8;
//
// Clock (100 MHz)
//
`define CLOCK_PERIOD 10.0
`define CLOCK_HALF_PERIOD (0.5 * `CLOCK_PERIOD)
reg clk = 1'b0;
always #`CLOCK_HALF_PERIOD clk = ~clk;
//
// Inputs, Outputs
//
reg rst_n;
reg ena;
wire rdy;
//
// Buffers (A, B, P)
//
wire [WORD_COUNTER_WIDTH-1:0] core_a_addr;
wire [WORD_COUNTER_WIDTH-1:0] core_b_addr;
wire [WORD_COUNTER_WIDTH-1:0] core_p_addr;
wire core_p_wren;
wire [ 32-1:0] core_a_data;
wire [ 32-1:0] core_b_data;
wire [ 32-1:0] core_p_data;
reg [WORD_COUNTER_WIDTH-1:0] tb_ab_addr;
reg [WORD_COUNTER_WIDTH-1:0] tb_p_addr;
reg tb_ab_wren;
reg [ 32-1:0] tb_a_data;
reg [ 32-1:0] tb_b_data;
wire [ 32-1:0] tb_p_data;
bram_1rw_1ro_readfirst # (.MEM_WIDTH(32), .MEM_ADDR_BITS(WORD_COUNTER_WIDTH))
bram_a
( .clk(clk),
.a_addr(tb_ab_addr), .a_wr(tb_ab_wren), .a_in(tb_a_data), .a_out(),
.b_addr(core_a_addr), .b_out(core_a_data)
);
bram_1rw_1ro_readfirst # (.MEM_WIDTH(32), .MEM_ADDR_BITS(WORD_COUNTER_WIDTH))
bram_b
( .clk(clk),
.a_addr(tb_ab_addr), .a_wr(tb_ab_wren), .a_in(tb_b_data), .a_out(),
.b_addr(core_b_addr), .b_out(core_b_data)
);
bram_1rw_1ro_readfirst # (.MEM_WIDTH(32), .MEM_ADDR_BITS(WORD_COUNTER_WIDTH))
bram_p
( .clk(clk),
.a_addr(core_p_addr), .a_wr(core_p_wren), .a_in(core_p_data), .a_out(),
.b_addr(tb_p_addr), .b_out(tb_p_data)
);
//
// UUT
//
ed25519_modular_multiplier uut
(
.clk (clk),
.rst_n (rst_n),
.ena (ena),
.rdy (rdy),
.a_addr (core_a_addr),
.b_addr (core_b_addr),
.p_addr (core_p_addr),
.p_wren (core_p_wren),
.a_din (core_a_data),
.b_din (core_b_data),
.p_dout (core_p_data)
);
//
// Testbench Routine
//
reg ok = 1;
initial begin
/* initialize control inputs */
rst_n = 0;
ena = 0;
/* wait for some time */
#200;
/* de-assert reset */
rst_n = 1;
/* wait for some time */
#100;
/* run tests */
$display("1. A1 * A1 = ...");
test_modular_multiplier(A1 , B1);
test_modular_multiplier(A1+B1, C1+C1);
test_modular_multiplier(F, F);
/* print result */
if (ok) $display("tb_modular_multiplier: SUCCESS");
else $display("tb_modular_multiplier: FAILURE");
//
#10000;
//
//$finish;
//
end
//
// Test Task
//
task test_modular_multiplier;
input [255:0] a;
input [255:0] b;
reg [255:0] a_shreg;
reg [255:0] b_shreg;
reg [255:0] p_shreg;
reg p_ok;
reg [511:0] ab;
reg [255:0] p_ref;
integer w;
begin
/* calculate reference value */
ab = {{256{1'b0}}, a} * {{256{1'b0}}, b};
p_ref = ab % {{31{8'hFF}}, 8'hDA};
/* initialize result */
p_ok = 0;
/* initialize shift registers */
a_shreg = a;
b_shreg = b;
/* start filling memories */
tb_ab_wren = 1;
/* write all the words */
for (w=0; w<OPERAND_NUM_WORDS; w=w+1) begin
/* set addresses */
tb_ab_addr = w[WORD_COUNTER_WIDTH-1:0];
/* set data words */
tb_a_data = a_shreg[31:0];
tb_b_data = b_shreg[31:0];
/* shift inputs */
a_shreg = {{32{1'bX}}, a_shreg[255:32]};
b_shreg = {{32{1'bX}}, b_shreg[255:32]};
/* wait for 1 clock tick */
#`CLOCK_PERIOD;
end
/* stop filling memories */
tb_ab_wren = 0;
/* wipe addresses */
tb_ab_addr = {WORD_COUNTER_WIDTH{1'bX}};
/* wipe data words */
tb_a_data = {32{1'bX}};
tb_b_data = {32{1'bX}};
/* start operation */
ena = 1;
/* clear flag */
#`CLOCK_PERIOD ena = 0;
/* wait for operation to complete */
while (!rdy) #`CLOCK_PERIOD;
/* read result */
for (w=0; w<OPERAND_NUM_WORDS; w=w+1) begin
/* set address */
tb_p_addr = w[WORD_COUNTER_WIDTH-1:0];
/* wait for 1 clock tick */
#`CLOCK_PERIOD;
/* store data word */
p_shreg = {tb_p_data, p_shreg[255:32]};
end
/* compare */
p_ok = (p_shreg === p_ref);
/* display results */
if (p_ok) $display("test_modular_multiplier(): CORRECT RESULT");
else begin
$display("test_modular_multiplier(): WRONG RESULT");
$display("XOR: %x", p_shreg ^ p_ref);
end
/* update global flag */
ok = ok & p_ok;
end
endtask
endmodule
//------------------------------------------------------------------------------
// End-of-File
//------------------------------------------------------------------------------
