Subversion Repositories cpu8080

////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 1995-2003 Xilinx, Inc.
// All Right Reserved.
////////////////////////////////////////////////////////////////////////////////
//   ____  ____ 
//  /   /\/   / 
// /___/  \  /    Vendor: Xilinx 
// \   \   \/     Version : 8.2.02i
//  \   \         Application : ISE
//  /   /         Filename : cpu8080_tbw.tfw
// /___/   /\     Timestamp : Sat Nov 18 13:39:13 2006
// \   \  /  \ 
//  \___\/\___\ 
//
//Command: 
//Design Name: cpu8080_tbw
//Device: Xilinx
//
`timescale 1ns/1ps

module cpu8080_tbw;
    wire [15:0] addr;
    reg [7:0] data$inout$reg = 8'b00000000;
    wire [7:0] data = data$inout$reg;
    wire readmem;
    wire writemem;
    wire readio;
    wire writeio;
    wire intr;
    wire inta;
    wire waitr;
    wire [2:0] r;
    wire [2:0] g;
    wire [2:0] b;
    wire hsync_n;
    wire vsync_n;
    reg ps2_clk = 1'b0;
    reg ps2_data = 1'b0;
    reg reset_n = 1'b0;
    reg clock = 1'b0;
    wire [7:0] diag;

    parameter PERIOD = 40;
    parameter real DUTY_CYCLE = 0.5;
    parameter OFFSET = 100;

    initial    // Clock process for clock
    begin
        #OFFSET;
        forever
        begin
            clock = 1'b0;
            #(PERIOD-(PERIOD*DUTY_CYCLE)) clock = 1'b1;
            #(PERIOD*DUTY_CYCLE);
        end
    end

    testbench UUT (
        .addr(addr),
        .data(data),
        .readmem(readmem),
        .writemem(writemem),
        .readio(readio),
        .writeio(writeio),
        .intr(intr),
        .inta(inta),
        .waitr(waitr),
        .r(r),
        .g(g),
        .b(b),
        .hsync_n(hsync_n),
        .vsync_n(vsync_n),
        .ps2_clk(ps2_clk),
        .ps2_data(ps2_data),
        .reset_n(reset_n),
        .clock(clock),
        .diag(diag));

    integer TX_FILE = 0;
    integer TX_ERROR = 0;
    
    initial begin  // Open the results file...
        TX_FILE = $fopen("results.txt");
        #200040 // Final time:  200040 ns
        if (TX_ERROR == 0) begin
            $display("No errors or warnings.");
            $fdisplay(TX_FILE, "No errors or warnings.");
        end else begin
            $display("%d errors found in simulation.", TX_ERROR);
            $fdisplay(TX_FILE, "%d errors found in simulation.", TX_ERROR);
        end
        $fclose(TX_FILE);
        $stop;
    end

    initial begin
        // -------------  Current Time:  110ns
        #110;
        ps2_clk = 1'b1;
        ps2_data = 1'b1;
        reset_n = 1'b0;
        data$inout$reg = 8'bZZZZZZZZ;
        // -------------------------------------
        // -------------  Current Time:  130ns
        #20;
        CHECK_intr(1'b0);
        CHECK_diag(8'bXXX11X00);
        // -------------------------------------
        // -------------  Current Time:  270ns
        #140;
        reset_n = 1'b1;
        // -------------------------------------
        // -------------  Current Time:  370ns
        #100;
        CHECK_b(3'bXXX);
        CHECK_g(3'bXXX);
        CHECK_r(3'bXXX);
        // -------------------------------------
        // -------------  Current Time:  390ns
        #20;
        ps2_data = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  410ns
        #20;
        CHECK_diag(8'bXXX01X00);
        // -------------------------------------
        // -------------  Current Time:  510ns
        #100;
        ps2_clk = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  530ns
        #20;
        CHECK_diag(8'bXXX00X00);
        // -------------------------------------
        // -------------  Current Time:  590ns
        #60;
        ps2_clk = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  650ns
        #60;
        CHECK_diag(8'bXXX00X01);
        // -------------------------------------
        // -------------  Current Time:  670ns
        #20;
        ps2_clk = 1'b1;
        // -------------------------------------
        // -------------  Current Time:  690ns
        #20;
        CHECK_diag(8'bXXX01X01);
        // -------------------------------------
        // -------------  Current Time:  830ns
        #140;
        ps2_clk = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  850ns
        #20;
        CHECK_diag(8'bXXX00X01);
        // -------------------------------------
        // -------------  Current Time:  990ns
        #140;
        ps2_clk = 1'b1;
        // -------------------------------------
        // -------------  Current Time:  1010ns
        #20;
        CHECK_diag(8'bXXX01X01);
        // -------------------------------------
        // -------------  Current Time:  1150ns
        #140;
        ps2_clk = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  1170ns
        #20;
        CHECK_diag(8'bXXX00X01);
        // -------------------------------------
        // -------------  Current Time:  1310ns
        #140;
        ps2_clk = 1'b1;
        // -------------------------------------
        // -------------  Current Time:  1330ns
        #20;
        CHECK_diag(8'bXXX01X01);
        // -------------------------------------
        // -------------  Current Time:  1470ns
        #140;
        ps2_clk = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  1490ns
        #20;
        CHECK_diag(8'bXXX00X01);
        // -------------------------------------
        // -------------  Current Time:  1630ns
        #140;
        ps2_clk = 1'b1;
        ps2_data = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  1650ns
        #20;
        CHECK_diag(8'bXXX01X01);
        // -------------------------------------
        // -------------  Current Time:  1790ns
        #140;
        ps2_clk = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  1810ns
        #20;
        CHECK_diag(8'bXXX00X01);
        // -------------------------------------
        // -------------  Current Time:  1950ns
        #140;
        ps2_clk = 1'b1;
        // -------------------------------------
        // -------------  Current Time:  1970ns
        #20;
        CHECK_diag(8'bXXX01X01);
        // -------------------------------------
        // -------------  Current Time:  1990ns
        #20;
        ps2_data = 1'b1;
        // -------------------------------------
        // -------------  Current Time:  2010ns
        #20;
        CHECK_diag(8'bXXX11X01);
        // -------------------------------------
        // -------------  Current Time:  2110ns
        #100;
        ps2_clk = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  2130ns
        #20;
        CHECK_diag(8'bXXX10X01);
        // -------------------------------------
        // -------------  Current Time:  2270ns
        #140;
        ps2_clk = 1'b1;
        // -------------------------------------
        // -------------  Current Time:  2290ns
        #20;
        CHECK_diag(8'bXXX11X01);
        // -------------------------------------
        // -------------  Current Time:  2430ns
        #140;
        ps2_clk = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  2450ns
        #20;
        CHECK_diag(8'bXXX10X01);
        // -------------------------------------
        // -------------  Current Time:  2590ns
        #140;
        ps2_clk = 1'b1;
        // -------------------------------------
        // -------------  Current Time:  2610ns
        #20;
        CHECK_diag(8'bXXX11X01);
        // -------------------------------------
        // -------------  Current Time:  2750ns
        #140;
        ps2_clk = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  2770ns
        #20;
        CHECK_diag(8'bXXX10X01);
        // -------------------------------------
        // -------------  Current Time:  2910ns
        #140;
        ps2_clk = 1'b1;
        // -------------------------------------
        // -------------  Current Time:  2930ns
        #20;
        CHECK_diag(8'bXXX11X01);
        // -------------------------------------
        // -------------  Current Time:  3070ns
        #140;
        ps2_clk = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  3090ns
        #20;
        CHECK_diag(8'bXXX10X01);
        // -------------------------------------
        // -------------  Current Time:  3230ns
        #140;
        ps2_clk = 1'b1;
        // -------------------------------------
        // -------------  Current Time:  3250ns
        #20;
        CHECK_diag(8'bXXX11X01);
        // -------------------------------------
        // -------------  Current Time:  3310ns
        #60;
        ps2_data = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  3330ns
        #20;
        CHECK_diag(8'bXXX01X01);
        // -------------------------------------
        // -------------  Current Time:  3390ns
        #60;
        ps2_clk = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  3410ns
        #20;
        CHECK_diag(8'bXXX00X01);
        // -------------------------------------
        // -------------  Current Time:  3550ns
        #140;
        ps2_clk = 1'b1;
        // -------------------------------------
        // -------------  Current Time:  3570ns
        #20;
        CHECK_diag(8'bXXX01X01);
        // -------------------------------------
        // -------------  Current Time:  3590ns
        #20;
        ps2_data = 1'b1;
        // -------------------------------------
        // -------------  Current Time:  3610ns
        #20;
        CHECK_diag(8'bXXX11X01);
        // -------------------------------------
        // -------------  Current Time:  3710ns
        #100;
        ps2_clk = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  3730ns
        #20;
        CHECK_diag(8'bXXX10X01);
        // -------------------------------------
        // -------------  Current Time:  3870ns
        #140;
        ps2_clk = 1'b1;
        // -------------------------------------
        // -------------  Current Time:  3890ns
        #20;
        CHECK_diag(8'bXXX11X01);
        // -------------------------------------
        // -------------  Current Time:  5910ns
        #2020;
        ps2_data = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  5930ns
        #20;
        CHECK_diag(8'bXXX01X01);
        // -------------------------------------
        // -------------  Current Time:  6070ns
        #140;
        ps2_clk = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  6090ns
        #20;
        CHECK_diag(8'bXXX00X01);
        // -------------------------------------
        // -------------  Current Time:  6230ns
        #140;
        ps2_clk = 1'b1;
        // -------------------------------------
        // -------------  Current Time:  6250ns
        #20;
        CHECK_diag(8'bXXX01X01);
        // -------------------------------------
        // -------------  Current Time:  6390ns
        #140;
        ps2_clk = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  6410ns
        #20;
        CHECK_diag(8'bXXX00X01);
        // -------------------------------------
        // -------------  Current Time:  6550ns
        #140;
        ps2_clk = 1'b1;
        // -------------------------------------
        // -------------  Current Time:  6570ns
        #20;
        CHECK_diag(8'bXXX01X01);
        // -------------------------------------
        // -------------  Current Time:  6630ns
        #60;
        ps2_data = 1'b1;
        // -------------------------------------
        // -------------  Current Time:  6650ns
        #20;
        CHECK_diag(8'bXXX11X01);
        // -------------------------------------
        // -------------  Current Time:  6710ns
        #60;
        ps2_clk = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  6730ns
        #20;
        CHECK_diag(8'bXXX10X01);
        // -------------------------------------
        // -------------  Current Time:  6870ns
        #140;
        ps2_clk = 1'b1;
        // -------------------------------------
        // -------------  Current Time:  6890ns
        #20;
        CHECK_diag(8'bXXX11X01);
        // -------------------------------------
        // -------------  Current Time:  6910ns
        #20;
        ps2_data = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  6930ns
        #20;
        CHECK_diag(8'bXXX01X01);
        // -------------------------------------
        // -------------  Current Time:  7030ns
        #100;
        ps2_clk = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  7050ns
        #20;
        CHECK_diag(8'bXXX00X01);
        // -------------------------------------
        // -------------  Current Time:  7190ns
        #140;
        ps2_clk = 1'b1;
        // -------------------------------------
        // -------------  Current Time:  7210ns
        #20;
        CHECK_diag(8'bXXX01X01);
        // -------------------------------------
        // -------------  Current Time:  7350ns
        #140;
        ps2_clk = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  7370ns
        #20;
        CHECK_diag(8'bXXX00X01);
        // -------------------------------------
        // -------------  Current Time:  7510ns
        #140;
        ps2_clk = 1'b1;
        // -------------------------------------
        // -------------  Current Time:  7530ns
        #20;
        CHECK_diag(8'bXXX01X01);
        // -------------------------------------
        // -------------  Current Time:  7550ns
        #20;
        ps2_data = 1'b1;
        // -------------------------------------
        // -------------  Current Time:  7570ns
        #20;
        CHECK_diag(8'bXXX11X01);
        // -------------------------------------
        // -------------  Current Time:  7670ns
        #100;
        ps2_clk = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  7690ns
        #20;
        CHECK_diag(8'bXXX10X01);
        // -------------------------------------
        // -------------  Current Time:  7830ns
        #140;
        ps2_clk = 1'b1;
        // -------------------------------------
        // -------------  Current Time:  7850ns
        #20;
        CHECK_diag(8'bXXX11X01);
        // -------------------------------------
        // -------------  Current Time:  7910ns
        #60;
        ps2_data = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  7930ns
        #20;
        CHECK_diag(8'bXXX01X01);
        // -------------------------------------
        // -------------  Current Time:  7990ns
        #60;
        ps2_clk = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  8010ns
        #20;
        CHECK_diag(8'bXXX00X01);
        // -------------------------------------
        // -------------  Current Time:  8150ns
        #140;
        ps2_clk = 1'b1;
        // -------------------------------------
        // -------------  Current Time:  8170ns
        #20;
        CHECK_diag(8'bXXX01X01);
        // -------------------------------------
        // -------------  Current Time:  8310ns
        #140;
        ps2_clk = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  8330ns
        #20;
        CHECK_diag(8'bXXX00X01);
        // -------------------------------------
        // -------------  Current Time:  8470ns
        #140;
        ps2_clk = 1'b1;
        // -------------------------------------
        // -------------  Current Time:  8490ns
        #20;
        CHECK_diag(8'bXXX01X01);
        // -------------------------------------
        // -------------  Current Time:  8630ns
        #140;
        ps2_clk = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  8650ns
        #20;
        CHECK_diag(8'bXXX00X01);
        // -------------------------------------
        // -------------  Current Time:  8790ns
        #140;
        ps2_clk = 1'b1;
        // -------------------------------------
        // -------------  Current Time:  8810ns
        #20;
        CHECK_diag(8'bXXX01X01);
        // -------------------------------------
        // -------------  Current Time:  8950ns
        #140;
        ps2_clk = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  8970ns
        #20;
        CHECK_diag(8'bXXX00X01);
        // -------------------------------------
        // -------------  Current Time:  9110ns
        #140;
        ps2_clk = 1'b1;
        // -------------------------------------
        // -------------  Current Time:  9130ns
        #20;
        CHECK_diag(8'bXXX01X01);
        // -------------------------------------
        // -------------  Current Time:  9190ns
        #60;
        ps2_data = 1'b1;
        // -------------------------------------
        // -------------  Current Time:  9210ns
        #20;
        CHECK_diag(8'bXXX11X01);
        // -------------------------------------
        // -------------  Current Time:  9270ns
        #60;
        ps2_clk = 1'b0;
        // -------------------------------------
        // -------------  Current Time:  9290ns
        #20;
        CHECK_diag(8'bXXX10X01);
        // -------------------------------------
        // -------------  Current Time:  9430ns
        #140;
        ps2_clk = 1'b1;
        // -------------------------------------
        // -------------  Current Time:  9450ns
        #20;
        CHECK_diag(8'bXXX11X01);
        // -------------------------------------
        // -------------  Current Time:  31090ns
        #21640;
        CHECK_b(3'b000);
        CHECK_g(3'b000);
        CHECK_r(3'b000);
        // -------------------------------------
        // -------------  Current Time:  31890ns
        #800;
        CHECK_hsync_n(1'b0);
        // -------------------------------------
        // -------------  Current Time:  39890ns
        #8000;
        CHECK_hsync_n(1'b1);
        // -------------------------------------
        // -------------  Current Time:  43890ns
        #4000;
        CHECK_b(3'bXXX);
        CHECK_g(3'bXXX);
        CHECK_r(3'bXXX);
        // -------------------------------------
        // -------------  Current Time:  95090ns
        #51200;
        CHECK_b(3'b000);
        CHECK_g(3'b000);
        CHECK_r(3'b000);
        // -------------------------------------
        // -------------  Current Time:  95890ns
        #800;
        CHECK_hsync_n(1'b0);
        // -------------------------------------
        // -------------  Current Time:  103890ns
        #8000;
        CHECK_hsync_n(1'b1);
        // -------------------------------------
        // -------------  Current Time:  107890ns
        #4000;
        CHECK_b(3'bXXX);
        CHECK_g(3'bXXX);
        CHECK_r(3'bXXX);
        // -------------------------------------
        // -------------  Current Time:  159090ns
        #51200;
        CHECK_b(3'b000);
        CHECK_g(3'b000);
        CHECK_r(3'b000);
        // -------------------------------------
        // -------------  Current Time:  159890ns
        #800;
        CHECK_hsync_n(1'b0);
        // -------------------------------------
        // -------------  Current Time:  167890ns
        #8000;
        CHECK_hsync_n(1'b1);
        // -------------------------------------
        // -------------  Current Time:  171890ns
        #4000;
        CHECK_b(3'bXXX);
        CHECK_g(3'bXXX);
        CHECK_r(3'bXXX);
        // -------------------------------------
    end

    task CHECK_addr;
        input [15:0] NEXT_addr;

        #0 begin
            if (NEXT_addr !== addr) begin
                $display("Error at time=%dns addr=%b, expected=%b", $time, addr, NEXT_addr);
                $fdisplay(TX_FILE, "Error at time=%dns addr=%b, expected=%b", $time, addr, NEXT_addr);
                $fflush(TX_FILE);
                TX_ERROR = TX_ERROR + 1;
            end
        end
    endtask
    task CHECK_readmem;
        input NEXT_readmem;

        #0 begin
            if (NEXT_readmem !== readmem) begin
                $display("Error at time=%dns readmem=%b, expected=%b", $time, readmem, NEXT_readmem);
                $fdisplay(TX_FILE, "Error at time=%dns readmem=%b, expected=%b", $time, readmem, NEXT_readmem);
                $fflush(TX_FILE);
                TX_ERROR = TX_ERROR + 1;
            end
        end
    endtask
    task CHECK_writemem;
        input NEXT_writemem;

        #0 begin
            if (NEXT_writemem !== writemem) begin
                $display("Error at time=%dns writemem=%b, expected=%b", $time, writemem, NEXT_writemem);
                $fdisplay(TX_FILE, "Error at time=%dns writemem=%b, expected=%b", $time, writemem, NEXT_writemem);
                $fflush(TX_FILE);
                TX_ERROR = TX_ERROR + 1;
            end
        end
    endtask
    task CHECK_readio;
        input NEXT_readio;

        #0 begin
            if (NEXT_readio !== readio) begin
                $display("Error at time=%dns readio=%b, expected=%b", $time, readio, NEXT_readio);
                $fdisplay(TX_FILE, "Error at time=%dns readio=%b, expected=%b", $time, readio, NEXT_readio);
                $fflush(TX_FILE);
                TX_ERROR = TX_ERROR + 1;
            end
        end
    endtask
    task CHECK_writeio;
        input NEXT_writeio;

        #0 begin
            if (NEXT_writeio !== writeio) begin
                $display("Error at time=%dns writeio=%b, expected=%b", $time, writeio, NEXT_writeio);
                $fdisplay(TX_FILE, "Error at time=%dns writeio=%b, expected=%b", $time, writeio, NEXT_writeio);
                $fflush(TX_FILE);
                TX_ERROR = TX_ERROR + 1;
            end
        end
    endtask
    task CHECK_intr;
        input NEXT_intr;

        #0 begin
            if (NEXT_intr !== intr) begin
                $display("Error at time=%dns intr=%b, expected=%b", $time, intr, NEXT_intr);
                $fdisplay(TX_FILE, "Error at time=%dns intr=%b, expected=%b", $time, intr, NEXT_intr);
                $fflush(TX_FILE);
                TX_ERROR = TX_ERROR + 1;
            end
        end
    endtask
    task CHECK_inta;
        input NEXT_inta;

        #0 begin
            if (NEXT_inta !== inta) begin
                $display("Error at time=%dns inta=%b, expected=%b", $time, inta, NEXT_inta);
                $fdisplay(TX_FILE, "Error at time=%dns inta=%b, expected=%b", $time, inta, NEXT_inta);
                $fflush(TX_FILE);
                TX_ERROR = TX_ERROR + 1;
            end
        end
    endtask
    task CHECK_waitr;
        input NEXT_waitr;

        #0 begin
            if (NEXT_waitr !== waitr) begin
                $display("Error at time=%dns waitr=%b, expected=%b", $time, waitr, NEXT_waitr);
                $fdisplay(TX_FILE, "Error at time=%dns waitr=%b, expected=%b", $time, waitr, NEXT_waitr);
                $fflush(TX_FILE);
                TX_ERROR = TX_ERROR + 1;
            end
        end
    endtask
    task CHECK_r;
        input [2:0] NEXT_r;

        #0 begin
            if (NEXT_r !== r) begin
                $display("Error at time=%dns r=%b, expected=%b", $time, r, NEXT_r);
                $fdisplay(TX_FILE, "Error at time=%dns r=%b, expected=%b", $time, r, NEXT_r);
                $fflush(TX_FILE);
                TX_ERROR = TX_ERROR + 1;
            end
        end
    endtask
    task CHECK_g;
        input [2:0] NEXT_g;

        #0 begin
            if (NEXT_g !== g) begin
                $display("Error at time=%dns g=%b, expected=%b", $time, g, NEXT_g);
                $fdisplay(TX_FILE, "Error at time=%dns g=%b, expected=%b", $time, g, NEXT_g);
                $fflush(TX_FILE);
                TX_ERROR = TX_ERROR + 1;
            end
        end
    endtask
    task CHECK_b;
        input [2:0] NEXT_b;

        #0 begin
            if (NEXT_b !== b) begin
                $display("Error at time=%dns b=%b, expected=%b", $time, b, NEXT_b);
                $fdisplay(TX_FILE, "Error at time=%dns b=%b, expected=%b", $time, b, NEXT_b);
                $fflush(TX_FILE);
                TX_ERROR = TX_ERROR + 1;
            end
        end
    endtask
    task CHECK_hsync_n;
        input NEXT_hsync_n;

        #0 begin
            if (NEXT_hsync_n !== hsync_n) begin
                $display("Error at time=%dns hsync_n=%b, expected=%b", $time, hsync_n, NEXT_hsync_n);
                $fdisplay(TX_FILE, "Error at time=%dns hsync_n=%b, expected=%b", $time, hsync_n, NEXT_hsync_n);
                $fflush(TX_FILE);
                TX_ERROR = TX_ERROR + 1;
            end
        end
    endtask
    task CHECK_vsync_n;
        input NEXT_vsync_n;

        #0 begin
            if (NEXT_vsync_n !== vsync_n) begin
                $display("Error at time=%dns vsync_n=%b, expected=%b", $time, vsync_n, NEXT_vsync_n);
                $fdisplay(TX_FILE, "Error at time=%dns vsync_n=%b, expected=%b", $time, vsync_n, NEXT_vsync_n);
                $fflush(TX_FILE);
                TX_ERROR = TX_ERROR + 1;
            end
        end
    endtask
    task CHECK_diag;
        input [7:0] NEXT_diag;

        #0 begin
            if (NEXT_diag !== diag) begin
                $display("Error at time=%dns diag=%b, expected=%b", $time, diag, NEXT_diag);
                $fdisplay(TX_FILE, "Error at time=%dns diag=%b, expected=%b", $time, diag, NEXT_diag);
                $fflush(TX_FILE);
                TX_ERROR = TX_ERROR + 1;
            end
        end
    endtask

endmodule