Subversion Repositories scalable_arbiter

/*

 * Copyright (c) 2009, Kendall Correll

 *

 * Permission to use, copy, modify, and distribute this software for any

 * purpose with or without fee is hereby granted, provided that the above

 * copyright notice and this permission notice appear in all copies.

 *

 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES

 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF

 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR

 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES

 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN

 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF

 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

 */

`timescale 1ns / 1ps

// This bench walks the demo through its sequence, but it does not verify outputs.

`define WIDTH 16

`define SELECT_WIDTH 4

`define TURNAROUND 3

`define TICK 10

`define HALF_TICK 5

module tb_arbiter3;

reg clock;

reg reset;

reg next_test;

reg next_step;

wire [`SELECT_WIDTH-1:0] select;

wire valid;

integer test_i;

`include "functions.v"

//

// UUT

//

demo #(

        .width(`WIDTH),

        .select_width(`SELECT_WIDTH)

) demo (

        .next_test(next_test),

        .next_step(next_step),

        .select(select),

        .valid(valid),

        .clock(clock),

        .reset(reset)

);

//

// clock

//

always @(clock)

begin

        #`HALF_TICK clock <= !clock;

end

//

// test sequence

//

initial begin

        clock = 1;

        next_test = 0;

        next_step = 0;

        reset = 1;

        #`TICK @(negedge clock) reset = 0;

        // step through the stimulus sequence, 'req_enable' is always high, so

        // reqs will be deasserted as soon as they are granted

        while(1'b1)

        begin

                #`TICK next_test = 1;

                #`TICK next_test = 0;

                for(test_i = 0; test_i < `WIDTH; test_i = test_i + 1)

                begin

                        #(`TURNAROUND*`TICK) next_step = 1;

                        #`TICK next_step = 0;

                end

        end

end

endmodule