//------------------------------------------------------------------------------
//
// tb_modular_subtractor_256.v
// -----------------------------------------------------------------------------
// Testbench for modular multi-word subtractor.
//
// Authors: Pavel Shatov
//
// Copyright (c) 2016, 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_subtractor_256;
//
// Test Vectors
//
localparam [255:0] N = 256'hffffffff00000001000000000000000000000000ffffffffffffffffffffffff;
localparam [255:0] X_1 = 256'h1ddbd0769df27bab1e234019dad09dccce1e87e2193b417ffa1a3465d7439ecd;
localparam [255:0] Y_1 = 256'h1f67cdc34bac91a072945d212f0a03442fc4855788583ecb7b2e375ad3848210;
localparam [255:0] X_2 = 256'hff563f653b1392a6fa6b0295a280f7a904a11e22d8ae468e220301d8ac232fcf;
localparam [255:0] Y_2 = 256'hf6f53c4b57b25453b68e923fb118e4f753d74af01fc58476dd15a80933453899;
//
// Core Parameters
//
localparam WORD_COUNTER_WIDTH = 3;
localparam OPERAND_NUM_WORDS = 8;
//
// Clock (100 MHz)
//
reg clk = 1'b0;
always #5 clk = ~clk;
//
// Inputs, Outputs
//
reg rst_n;
reg ena;
wire rdy;
//
// Buffers (X, Y, N)
//
wire [WORD_COUNTER_WIDTH-1:0] core_xy_addr;
wire [WORD_COUNTER_WIDTH-1:0] core_n_addr;
wire [WORD_COUNTER_WIDTH-1:0] core_d_addr;
wire core_d_wren;
wire [ 31:0] core_x_data;
wire [ 31:0] core_y_data;
wire [ 31:0] core_n_data;
wire [ 31:0] core_d_data;
reg [WORD_COUNTER_WIDTH-1:0] tb_xyn_addr;
reg [WORD_COUNTER_WIDTH-1:0] tb_d_addr;
reg tb_xyn_wren;
reg [ 31:0] tb_x_data;
reg [ 31:0] tb_y_data;
reg [ 31:0] tb_n_data;
wire [ 31:0] tb_d_data;
bram_1rw_1ro_readfirst #
(
.MEM_WIDTH (32),
.MEM_ADDR_BITS (WORD_COUNTER_WIDTH)
)
bram_x
(
.clk (clk),
.a_addr (tb_xyn_addr),
.a_wr (tb_xyn_wren),
.a_in (tb_x_data),
.a_out (),
.b_addr (core_xy_addr),
.b_out (core_x_data)
);
bram_1rw_1ro_readfirst #
(
.MEM_WIDTH (32),
.MEM_ADDR_BITS (WORD_COUNTER_WIDTH)
)
bram_y
(
.clk (clk),
.a_addr (tb_xyn_addr),
.a_wr (tb_xyn_wren),
.a_in (tb_y_data),
.a_out (),
.b_addr (core_xy_addr),
.b_out (core_y_data)
);
bram_1rw_1ro_readfirst #
(
.MEM_WIDTH (32),
.MEM_ADDR_BITS (WORD_COUNTER_WIDTH)
)
bram_n
(
.clk (clk),
.a_addr (tb_xyn_addr),
.a_wr (tb_xyn_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 (WORD_COUNTER_WIDTH)
)
bram_s
(
.clk (clk),
.a_addr (core_d_addr),
.a_wr (core_d_wren),
.a_in (core_d_data),
.a_out (),
.b_addr (tb_d_addr),
.b_out (tb_d_data)
);
//
// UUT
//
modular_subtractor #
(
.WORD_COUNTER_WIDTH (WORD_COUNTER_WIDTH),
.OPERAND_NUM_WORDS (OPERAND_NUM_WORDS)
)
uut
(
.clk (clk),
.rst_n (rst_n),
.ena (ena),
.rdy (rdy),
.ab_addr (core_xy_addr),
.n_addr (core_n_addr),
.d_addr (core_d_addr),
.d_wren (core_d_wren),
.a_din (core_x_data),
.b_din (core_y_data),
.n_din (core_n_data),
.d_dout (core_d_data)
);
//
// Testbench Routine
//
reg ok = 1;
initial begin
/* initialize control inputs */
rst_n = 0;
ena = 0;
tb_xyn_wren = 0;
/* wait for some time */
#200;
/* de-assert reset */
rst_n = 1;
/* wait for some time */
#100;
/* run tests */
test_modular_subtractor(X_1, Y_1, N);
test_modular_subtractor(X_2, Y_2, N);
test_modular_subtractor(Y_1, X_1, N);
test_modular_subtractor(Y_2, X_2, N);
test_modular_subtractor(X_1, X_2, N);
test_modular_subtractor(X_2, X_1, N);
test_modular_subtractor(Y_1, Y_2, N);
test_modular_subtractor(Y_2, Y_1, N);
test_modular_subtractor(X_1, Y_2, N);
test_modular_subtractor(Y_2, X_1, N);
test_modular_subtractor(X_2, Y_1, N);
test_modular_subtractor(Y_1, X_2, N);
/* print result */
if (ok) $display("tb_modular_subtractor_256: SUCCESS");
else $display("tb_modular_subtractor_256: FAILURE");
//
$finish;
//
end
//
// Test Task
//
reg [256:0] d;
wire [255:0] d_dummy = d[255:0];
reg d_ok;
integer w;
reg [255:0] x_shreg;
reg [255:0] y_shreg;
reg [255:0] n_shreg;
reg [255:0] d_shreg;
task test_modular_subtractor;
input [255:0] x;
input [255:0] y;
input [255:0] n;
begin
/* start filling memories */
tb_xyn_wren = 1;
/* initialize shift registers */
x_shreg = x;
y_shreg = y;
n_shreg = n;
/* write all the words */
for (w=0; w<OPERAND_NUM_WORDS; w=w+1) begin
/* set addresses */
tb_xyn_addr = w[WORD_COUNTER_WIDTH-1:0];
/* set data words */
tb_x_data = x_shreg[31:0];
tb_y_data = y_shreg[31:0];
tb_n_data = n_shreg[31:0];
/* shift inputs */
x_shreg = {{32{1'bX}}, x_shreg[255:32]};
y_shreg = {{32{1'bX}}, y_shreg[255:32]};
n_shreg = {{32{1'bX}}, n_shreg[255:32]};
/* wait for 1 clock tick */
#10;
end
/* wipe addresses */
tb_xyn_addr = {WORD_COUNTER_WIDTH{1'bX}};
/* wipe data words */
tb_x_data = {32{1'bX}};
tb_y_data = {32{1'bX}};
tb_n_data = {32{1'bX}};
/* stop filling memories */
tb_xyn_wren = 0;
/* calculate reference value */
d = {1'b0, (x < y) ? n : {256{1'b0}}};
d = d + {1'b0, x} - {1'b0, y};
/* start operation */
ena = 1;
/* clear flag */
#10 ena = 0;
/* wait for operation to complete */
while (!rdy) #10;
/* read result */
for (w=0; w<OPERAND_NUM_WORDS; w=w+1) begin
/* set address */
tb_d_addr = w[WORD_COUNTER_WIDTH-1:0];
/* wait for 1 clock tick */
#10;
/* store data word */
d_shreg = {tb_d_data, d_shreg[255:32]};
end
/* compare */
d_ok = (d_shreg == d[255:0]);
/* display results */
$display("test_modular_subtractor(): %s", d_ok ? "OK" : "ERROR");
/* update global flag */
ok = ok && d_ok;
end
endtask
endmodule
//------------------------------------------------------------------------------
// End-of-File
//------------------------------------------------------------------------------
