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//////////////////////////////////////////////////////////////////////
////                                                              ////
////  dbg_tb.v                                                    ////
////                                                              ////
////                                                              ////
////  This file is part of the SoC/OpenRISC Development Interface ////
////  http://www.opencores.org/projects/DebugInterface/           ////
////                                                              ////
////  Author(s):                                                  ////
////       Igor Mohor (igorm@opencores.org)                       ////
////                                                              ////
////                                                              ////
////  All additional information is avaliable in the README.txt   ////
////  file.                                                       ////
////                                                              ////
//////////////////////////////////////////////////////////////////////
////                                                              ////
//// Copyright (C) 2000 - 2004 Authors                            ////
////                                                              ////
//// This source file may be used and distributed without         ////
//// restriction provided that this copyright statement is not    ////
//// removed from the file and that any derivative work contains  ////
//// the original copyright notice and the associated disclaimer. ////
////                                                              ////
//// This source file is free software; you can redistribute it   ////
//// and/or modify it under the terms of the GNU Lesser General   ////
//// Public License as published by the Free Software Foundation; ////
//// either version 2.1 of the License, or (at your option) any   ////
//// later version.                                               ////
////                                                              ////
//// This source is distributed in the hope that it will be       ////
//// useful, but WITHOUT ANY WARRANTY; without even the implied   ////
//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR      ////
//// PURPOSE.  See the GNU Lesser General Public License for more ////
//// details.                                                     ////
////                                                              ////
//// You should have received a copy of the GNU Lesser General    ////
//// Public License along with this source; if not, download it   ////
//// from http://www.opencores.org/lgpl.shtml                     ////
////                                                              ////
//////////////////////////////////////////////////////////////////////
//
// CVS Revision History
//
// $Log: not supported by cvs2svn $
// Revision 1.33  2004/01/20 14:05:26  mohor
// Data latching changed when testing WB.
//
// Revision 1.32  2004/01/20 10:23:21  mohor
// More debug data added.
//
// Revision 1.31  2004/01/20 09:07:44  mohor
// CRC generation iand verification in bench changed.
//
// Revision 1.30  2004/01/20 08:03:35  mohor
// IDCODE test improved.
//
// Revision 1.29  2004/01/19 13:13:18  mohor
// Define tap_defines.v added to test bench.
//
// Revision 1.28  2004/01/19 12:38:10  mohor
// Waiting for "ready" improved.
//
// Revision 1.27  2004/01/17 18:01:31  mohor
// New version.
//
// Revision 1.26  2004/01/17 17:01:25  mohor
// Almost finished.
//
// Revision 1.25  2004/01/16 14:51:24  mohor
// cpu registers added.
//
// Revision 1.24  2004/01/15 10:47:13  mohor
// Working.
//
// Revision 1.23  2004/01/14 22:59:01  mohor
// Temp version.
//
// Revision 1.22  2004/01/13 11:28:30  mohor
// tmp version.
//
// Revision 1.21  2004/01/10 07:50:41  mohor
// temp version.
//
// Revision 1.20  2004/01/09 12:49:23  mohor
// tmp version.
//
// Revision 1.19  2004/01/08 17:53:12  mohor
// tmp version.
//
// Revision 1.18  2004/01/07 11:59:48  mohor
// temp4 version.
//
// Revision 1.17  2004/01/06 17:14:59  mohor
// temp3 version.
//
// Revision 1.16  2004/01/05 12:16:50  mohor
// tmp2 version.
//
// Revision 1.15  2003/12/23 14:26:01  mohor
// New version of the debug interface. Not finished, yet.
//
// Revision 1.14  2003/10/23 16:16:30  mohor
// CRC logic changed.
//
// Revision 1.13  2003/08/28 13:54:33  simons
// Three more chains added for cpu debug access.
//
// Revision 1.12  2002/05/07 14:44:52  mohor
// mon_cntl_o signals that controls monitor mux added.
//
// Revision 1.11  2002/03/12 14:32:26  mohor
// Few outputs for boundary scan chain added.
//
// Revision 1.10  2002/03/08 15:27:08  mohor
// Structure changed. Hooks for jtag chain added.
//
// Revision 1.9  2001/10/19 11:39:20  mohor
// dbg_timescale.v changed to timescale.v This is done for the simulation of
// few different cores in a single project.
//
// Revision 1.8  2001/10/17 10:39:17  mohor
// bs_chain_o added.
//
// Revision 1.7  2001/10/16 10:10:18  mohor
// Signal names changed to lowercase.
//
// Revision 1.6  2001/10/15 09:52:50  mohor
// Wishbone interface added, few fixes for better performance,
// hooks for boundary scan testing added.
//
// Revision 1.5  2001/09/24 14:06:12  mohor
// Changes connected to the OpenRISC access (SPR read, SPR write).
//
// Revision 1.4  2001/09/20 10:10:29  mohor
// Working version. Few bugs fixed, comments added.
//
// Revision 1.3  2001/09/19 11:54:03  mohor
// Minor changes for simulation.
//
// Revision 1.2  2001/09/18 14:12:43  mohor
// Trace fixed. Some registers changed, trace simplified.
//
// Revision 1.1.1.1  2001/09/13 13:49:19  mohor
// Initial official release.
//
// Revision 1.3  2001/06/01 22:23:40  mohor
// This is a backup. It is not a fully working version. Not for use, yet.
//
// Revision 1.2  2001/05/18 13:10:05  mohor
// Headers changed. All additional information is now avaliable in the README.txt file.
//
// Revision 1.1.1.1  2001/05/18 06:35:15  mohor
// Initial release
//
//
 
 
`include "timescale.v"
`include "tap_defines.v"
`include "dbg_defines.v"
`include "dbg_wb_defines.v"
`include "dbg_cpu_defines.v"
 
// Test bench
module dbg_tb;
 
parameter TCLK = 50;   // Clock half period (Clok period = 100 ns => 10 MHz)
 
reg   tms_pad_i;
reg   tck_pad_i;
reg   trst_pad_i;
reg   tdi_pad_i;
wire  tdo_pad_o;
wire  tdo_padoe_o;
 
wire  shift_dr_o;
wire  pause_dr_o;
wire  update_dr_o;
wire  capture_dr_o;
 
wire  extest_select_o;
wire  sample_preload_select_o;
wire  mbist_select_o;
wire  debug_select_o;
 
// WISHBONE common signals
reg   wb_rst_i;
reg   wb_clk_i;
 
// WISHBONE master interface
wire [31:0] wb_adr_o;
wire [31:0] wb_dat_o;
wire [31:0] wb_dat_i;
wire        wb_cyc_o;
wire        wb_stb_o;
wire  [3:0] wb_sel_o;
wire        wb_we_o;
wire        wb_ack_i;
wire        wb_cab_o;
wire        wb_err_i;
wire  [2:0] wb_cti_o;
wire  [1:0] wb_bte_o;
 
// CPU signals
wire        cpu_clk_i;
wire [31:0] cpu_addr_o;
wire [31:0] cpu_data_i;
wire [31:0] cpu_data_o;
wire        cpu_bp_i;
wire        cpu_stall_o;
wire        cpu_stall_all_o;
wire        cpu_stb_o;
wire  [`CPU_NUM -1:0]  cpu_sel_o;
wire        cpu_we_o;
wire        cpu_ack_i;
wire        cpu_rst_o;
 
// Text used for easier debugging
reg [199:0] test_text;
reg   [2:0] last_wb_cmd;
reg [199:0] last_wb_cmd_text;
 
reg  [31:0] wb_data [0:4095];   // Data that is written to (read from) wishbone is stored here. 
 
 
 
wire  tdo_o;
 
wire  debug_tdi_i;
wire  bs_chain_tdi_i;
wire  mbist_tdi_i;
 
reg   test_enabled;
 
reg [31:0] result;
reg [31:0] in_data_le, in_data_be;
reg [31:0] id;
 
wire crc_match_in;
reg [31:0] crc_in;
reg [31:0] crc_out;
 
 
wire tdo;
 
assign tdo = tdo_padoe_o? tdo_pad_o : 1'hz;
 
// Connecting TAP module
tap_top i_tap_top (
                    .tms_pad_i        (tms_pad_i), 
                    .tck_pad_i        (tck_pad_i), 
                    .trst_pad_i       (!trst_pad_i), 
                    .tdi_pad_i        (tdi_pad_i), 
                    .tdo_pad_o        (tdo_pad_o), 
                    .tdo_padoe_o      (tdo_padoe_o), 
 
                    // TAP states
                    .shift_dr_o       (shift_dr_o),
                    .pause_dr_o       (pause_dr_o),
                    .update_dr_o      (update_dr_o),
                    .capture_dr_o     (capture_dr_o),
 
                    // Select signals for boundary scan or mbist
                    .extest_select_o  (extest_select_o),
                    .sample_preload_select_o(sample_preload_select_o),
                    .mbist_select_o   (mbist_select_o),
                    .debug_select_o   (debug_select_o),
 
                    // TDO signal that is connected to TDI of sub-modules.
                    .tdo_o            (tdo_o),
 
                    // TDI signals from sub-modules
                    .debug_tdi_i      (debug_tdi_i),        // from debug module
                    .bs_chain_tdi_i   (bs_chain_tdi_i),  // from Boundary Scan Chain
                    .mbist_tdi_i      (mbist_tdi_i)         // from Mbist Chain
 
               );
 
 
// Connecting debug top module
dbg_top i_dbg_top  (
                    .tck_i            (tck_pad_i),
                    .tdi_i            (tdo_o),
                    .tdo_o            (debug_tdi_i),
 
                    // TAP states
                    .shift_dr_i       (shift_dr_o),
                    .pause_dr_i       (pause_dr_o),
                    .update_dr_i      (update_dr_o),
 
                    // Instructions
                    .debug_select_i   (debug_select_o),
 
                    // WISHBONE common signals
                    .wb_rst_i         (wb_rst_i),
                    .wb_clk_i         (wb_clk_i),
 
                    // WISHBONE master interface
                    .wb_adr_o         (wb_adr_o),
                    .wb_dat_o         (wb_dat_o),
                    .wb_dat_i         (wb_dat_i),
                    .wb_cyc_o         (wb_cyc_o),
                    .wb_stb_o         (wb_stb_o),
                    .wb_sel_o         (wb_sel_o),
                    .wb_we_o          (wb_we_o),
                    .wb_ack_i         (wb_ack_i),
                    .wb_cab_o         (wb_cab_o),
                    .wb_err_i         (wb_err_i),
                    .wb_cti_o         (wb_cti_o),
                    .wb_bte_o         (wb_bte_o),
 
                    // CPU signals
                    .cpu_clk_i        (cpu_clk_i),
                    .cpu_addr_o       (cpu_addr_o),
                    .cpu_data_i       (cpu_data_i),
                    .cpu_data_o       (cpu_data_o),
                    .cpu_bp_i         (cpu_bp_i),
                    .cpu_stall_o      (cpu_stall_o),
                    .cpu_stall_all_o  (cpu_stall_all_o),
                    .cpu_stb_o        (cpu_stb_o),
                    .cpu_sel_o        (cpu_sel_o),
                    .cpu_we_o         (cpu_we_o),
                    .cpu_ack_i        (cpu_ack_i),
                    .cpu_rst_o        (cpu_rst_o)
 
 
 
 
                   );
 
 
 
wb_slave_behavioral wb_slave
                   (
                    .CLK_I            (wb_clk_i),
                    .RST_I            (wb_rst_i),
                    .ACK_O            (wb_ack_i),
                    .ADR_I            (wb_adr_o),
                    .CYC_I            (wb_cyc_o),
                    .DAT_O            (wb_dat_i),
                    .DAT_I            (wb_dat_o),
                    .ERR_O            (wb_err_i),
                    .RTY_O            (),      // NOT USED for now!
                    .SEL_I            (wb_sel_o),
                    .STB_I            (wb_stb_o),
                    .WE_I             (wb_we_o),
                    .CAB_I            (1'b0)
                   );
 
 
 
cpu_behavioral i_cpu_behavioral
                   (
                    // CPU signals
                    .cpu_rst_i        (wb_rst_i),
                    .cpu_clk_o        (cpu_clk_i),
                    .cpu_addr_i       (cpu_addr_o),
                    .cpu_data_o       (cpu_data_i),
                    .cpu_data_i       (cpu_data_o),
                    .cpu_bp_o         (cpu_bp_i),
                    .cpu_stall_i      (cpu_stall_o),
                    .cpu_stall_all_i  (cpu_stall_all_o),
                    .cpu_stb_i        (cpu_stb_o),
                    .cpu_sel_i        (cpu_sel_o),
                    .cpu_we_i         (cpu_we_o),
                    .cpu_ack_o        (cpu_ack_i),
                    .cpu_rst_o        (cpu_rst_o)
                   );
 
 
 
 
// Initial values
initial
begin
  test_enabled = 1'b0;
  trst_pad_i = 1'b1;
  tms_pad_i = 1'hz;
  tck_pad_i = 1'hz;
  tdi_pad_i = 1'hz;
 
  #100;
  trst_pad_i = 1'b0;
  #100;
  trst_pad_i = 1'b1;
  #1 test_enabled<=#1 1'b1;
end
 
initial
begin
  wb_rst_i = 1'b0;
  #1000;
  wb_rst_i = 1'b1;
  #1000;
  wb_rst_i = 1'b0;
 
  // Initial values for wishbone slave model
  wb_slave.cycle_response(`ACK_RESPONSE, 9'h55, 8'h2);   // (`ACK_RESPONSE, wbs_waits, wbs_retries);
end
 
initial
begin
  wb_clk_i = 1'b0;
  forever #5 wb_clk_i = ~wb_clk_i;
end
 
always @ (posedge test_enabled)
begin
 
  $display("//////////////////////////////////////////////////////////////////");
  $display("//                                                              //");
  $display("//  (%0t) dbg_tb starting                                     //", $time);
  $display("//                                                              //");
  $display("//////////////////////////////////////////////////////////////////");
 
  initialize_memory(32'h12340000, 32'h00100000);  // Initialize 0x100000 bytes starting from address 0x12340000
 
  reset_tap;
 
  #500;
  goto_run_test_idle;
 
  // Testing read and write to internal registers
  #10000;
 
  set_instruction(`IDCODE);
  read_id_code(id);
 
  $display("\tRead ID     = 0x%0x", id);
  $display("\tExpected ID = 0x%0x", `IDCODE_VALUE);
 
  set_instruction(`DEBUG);
  #10000;
 
  chain_select(`WISHBONE_DEBUG_CHAIN, 1'b0);   // {chain, gen_crc_err}
 
//  #10000;
//  xxx(4'b1001, 32'he579b242);
 
  #10000;
 
//  debug_wishbone(`WB_READ8, 1'b0, 32'h12345678, 16'h4, 1'b0, "abc 1"); // {command, ready, addr, length, gen_crc_err, text}
//  debug_wishbone(`WB_READ8, 1'b0, 32'h12345679, 16'h4, 1'b0, "abc 2"); // {command, ready, addr, length, gen_crc_err, text}
//  debug_wishbone(`WB_READ8, 1'b0, 32'h1234567a, 16'h4, 1'b0, "abc 3"); // {command, ready, addr, length, gen_crc_err, text}
//
//  debug_wishbone(`WB_READ16, 1'b0, 32'h12345678, 16'h4, 1'b0, "abc 4"); // {command, ready, addr, length, gen_crc_err, text}
//  debug_wishbone(`WB_READ16, 1'b0, 32'h1234567a, 16'h4, 1'b0, "abc 5"); // {command, ready, addr, length, gen_crc_err, text}
//
  debug_wishbone(`WB_READ32, 1'b0, 32'h12345678, 16'h4, 1'b0, "read32 1"); // {command, ready, addr, length, gen_crc_err, text}
//
//  debug_wishbone(`WB_READ16, 1'b0, 32'h12345679, 16'h4, 1'b0, "abc 6"); // {command, ready, addr, length, gen_crc_err, text}
 
  #10000;
//  xxx(4'b1001, 32'he579b242);
 
  debug_wishbone(`WB_READ32, 1'b1, 32'h12345678, 16'h4, 1'b0, "read32 2"); // {command, ready, addr, length, gen_crc_err, text}
 
  #10000;
  wb_slave.cycle_response(`ACK_RESPONSE, 9'h55, 8'h2);   // (`ACK_RESPONSE, wbs_waits, wbs_retries);
  debug_wishbone(`WB_READ32, 1'b1, 32'h12346668, 16'h4, 1'b0, "read32 3"); // {command, ready, addr, length, gen_crc_err, text}
 
  #10000;
  wb_slave.cycle_response(`ERR_RESPONSE, 9'h03, 8'h2);   // (`ERR_RESPONSE, wbs_waits, wbs_retries);
  debug_wishbone(`WB_READ32, 1'b1, 32'h12346668, 16'h4, 1'b0, "read32 4"); // {command, ready, addr, length, gen_crc_err, text}
 
  #10000;
  debug_wishbone(`WB_STATUS, 1'b0, 32'h0, 16'h0, 1'b0, "status 1"); // {command, ready, addr, length, gen_crc_err, text}
 
  #10000;
  debug_wishbone(`WB_STATUS, 1'b0, 32'h0, 16'h0, 1'b0, "status 2"); // {command, ready, addr, length, gen_crc_err, text}
 
  #10000;
  wb_slave.cycle_response(`ACK_RESPONSE, 9'h012, 8'h2);   // (`ACK_RESPONSE, wbs_waits, wbs_retries);
  debug_wishbone(`WB_READ32, 1'b1, 32'h12347778, 16'hc, 1'b0, "read32 5"); // {command, ready, addr, length, gen_crc_err, text}
 
  #10000;
  debug_wishbone(`WB_WRITE32, 1'b0, 32'h12346668, 16'h8, 1'b0, "wr32 len8"); // {command, ready, addr, length, gen_crc_err, text}
 
  #10000;
  debug_wishbone(`WB_WRITE16, 1'b0, 32'h12344446, 16'h8, 1'b0, "wr16 len8"); // {command, ready, addr, length, gen_crc_err, text}
 
  #10000;
  debug_wishbone(`WB_WRITE8, 1'b0, 32'h1234010e, 16'h8, 1'b0, "wr8 len8"); // {command, ready, addr, length, gen_crc_err, text}
 
  #10000;
  debug_wishbone(`WB_GO, 1'b0, 32'h0, 16'h0, 1'b0, "go 1"); // {command, ready, addr, length, gen_crc_err, text}
 
  #10000;
  debug_wishbone(`WB_READ32, 1'b1, 32'h12340100, 16'hc, 1'b0, "read32 6"); // {command, ready, addr, length, gen_crc_err, text}
//  debug_wishbone(`WB_READ32, 1'b1, 32'h12340100, 16'hfffc, 1'b0, "read32 6"); // {command, ready, addr, length, gen_crc_err, text}
 
  #10000;
//  debug_wishbone(`WB_READ16, 1'b1, 32'h12340102, 16'he, 1'b0, "read16 7"); // {command, ready, addr, length, gen_crc_err, text}
//  debug_wishbone(`WB_READ16, 1'b1, 32'h12340102, 16'hfffe, 1'b0, "read16 7"); // {command, ready, addr, length, gen_crc_err, text}
 
  #10000;
//  debug_wishbone(`WB_READ8, 1'b1, 32'h12348804, 16'h6, 1'b0, "read8 8"); // {command, ready, addr, length, gen_crc_err, text}  
//  debug_wishbone(`WB_READ8, 1'b1, 32'h12348804, 16'hfffc, 1'b0, "read8 8"); // {command, ready, addr, length, gen_crc_err, text}
 
  #10000;
  debug_wishbone(`WB_GO, 1'b0, 32'h0, 16'h0, 1'b0, "go 2"); // {command, ready, addr, length, gen_crc_err, text}
 
  #10000;
  chain_select(`CPU_DEBUG_CHAIN, 1'b0);   // {chain, gen_crc_err}
 
 
 
 
  // Select cpu0
  #10000;
  debug_cpu(`CPU_WRITE_REG, `CPU_SEL_ADR, 32'h0, 1'b0, result, "select cpu 0"); // {command, addr, data, gen_crc_err, result, text}
 
  #10000;
  debug_cpu(`CPU_GO, 32'h0, 32'h1, 1'b0, result, "go cpu"); // {command, addr, data, gen_crc_err, result, text}
 
  // Read register
  #10000;
  debug_cpu(`CPU_READ_REG, `CPU_SEL_ADR, 32'h0, 1'b0, result, "cpu_read_reg"); // {command, addr, data, gen_crc_err, result, text}
 
  #10000;
  debug_cpu(`CPU_GO, 32'h0, 32'hff, 1'b0, result, "go cpu"); // {command, addr, data, gen_crc_err, result, text}
 
  // Stall cpu0
  #10000;
  debug_cpu(`CPU_WRITE_REG, `CPU_OP_ADR, 32'h0, 1'b0, result, "stall cpu0"); // {command, addr, data, gen_crc_err, result, text}
 
  #10000;
  debug_cpu(`CPU_GO, 32'h0, 32'h1, 1'b0, result, "go cpu"); // {command, addr, data, gen_crc_err, result, text}
 
  // write to cpu 32-bit
  #10000;
  debug_cpu(`CPU_WRITE32, 32'h32323232, 32'h0, 1'b0, result, "cpu_write_32"); // {command, addr, data, gen_crc_err, result, text}
 
  #10000;
  debug_cpu(`CPU_GO, 32'h0, 32'hdeadbeef, 1'b0, result, "go cpu"); // {command, addr, data, gen_crc_err, result, text}
 
  // read from cpu 32-bit
  #10000;
  debug_cpu(`CPU_READ32, 32'h32323232, 32'h0, 1'b0, result, "cpu_read_32"); // {command, addr, data, gen_crc_err, result, text}
 
  #10000;
  debug_cpu(`CPU_GO, 32'h0, 32'hdeadbeef, 1'b0, result, "go cpu"); // {command, addr, data, gen_crc_err, result, text}
 
  // write to cpu 8-bit
  #10000;
  debug_cpu(`CPU_WRITE8, 32'h08080808, 32'h0, 1'b0, result, "cpu_write_8"); // {command, addr, data, gen_crc_err, result, text}
 
  #10000;
  debug_cpu(`CPU_GO, 32'h0, 32'hdeadbeef, 1'b0, result, "go cpu"); // {command, addr, data, gen_crc_err, result, text}
 
  // read from cpu 8-bit
  #10000;
  debug_cpu(`CPU_READ8, 32'h08080808, 32'h0, 1'b0, result, "cpu_read_8"); // {command, addr, data, gen_crc_err, result, text}
 
  #10000;
  debug_cpu(`CPU_GO, 32'h0, 32'hdeadbeef, 1'b0, result, "go cpu"); // {command, addr, data, gen_crc_err, result, text}
 
 
 
 
 
 
 
 
 
 
  #5000 gen_clk(1);            // One extra TCLK for debugging purposes
  $display("\n\nSimulation end.");
  #1000 $stop;
 
end
 
 
task initialize_memory;
  input [31:0] start_addr;
  input [31:0] length;
  integer i;
  reg [31:0] addr;
  begin
    for (i=0; i<length; i=i+4)  // This data will be return from wb slave
      begin
        addr = start_addr + i;
        wb_slave.wr_mem(addr, {addr[7:0], addr[7:0]+2'd1, addr[7:0]+2'd2, addr[7:0]+2'd3}, 4'hf);    // adr, data, sel
      end
    for (i=0; i<4096; i=i+1)  // This data will be written to wb slave
      begin
        wb_data[i] <= {i[7:0], i[7:0]+2'd1, i[7:0]+2'd2, i[7:0]+2'd3};
      end
  end
endtask
 
 
 
// Generation of the TCLK signal
task gen_clk;
  input [7:0] num;
  integer i;
  begin
    for(i=0; i<num; i=i+1)
      begin
        #TCLK tck_pad_i<=1;
        #TCLK tck_pad_i<=0;
      end
  end
endtask
 
 
// TAP reset
task reset_tap;
  begin
    $display("(%0t) Task reset_tap", $time);
    tms_pad_i<=#1 1'b1;
    gen_clk(5);
  end
endtask
 
 
// Goes to RunTestIdle state
task goto_run_test_idle;
  begin
    $display("(%0t) Task goto_run_test_idle", $time);
    tms_pad_i<=#1 1'b0;
    gen_clk(1);
  end
endtask
 
 
 
// sets the instruction to the IR register and goes to the RunTestIdle state
task set_instruction;
  input [3:0] instr;
  integer i;
 
  begin
    case (instr)
      `EXTEST          : $display("(%0t) Task set_instruction (EXTEST)", $time); 
      `SAMPLE_PRELOAD  : $display("(%0t) Task set_instruction (SAMPLE_PRELOAD)", $time); 
      `IDCODE          : $display("(%0t) Task set_instruction (IDCODE)", $time);
      `DEBUG           : $display("(%0t) Task set_instruction (DEBUG)", $time);
      `MBIST           : $display("(%0t) Task set_instruction (MBIST)", $time);
      `BYPASS          : $display("(%0t) Task set_instruction (BYPASS)", $time);
      default
                       begin
                         $display("(%0t) Task set_instruction (Unsupported instruction !!!)", $time);
                         $display("\tERROR: Unsupported instruction !!!", $time);
                         $stop;
                       end
    endcase
 
    tms_pad_i<=#1 1;
    gen_clk(2);
    tms_pad_i<=#1 0;
    gen_clk(2);  // we are in shiftIR
 
    for(i=0; i<`IR_LENGTH-1; i=i+1)
    begin
      tdi_pad_i<=#1 instr[i];
      gen_clk(1);
    end
 
    tdi_pad_i<=#1 instr[i]; // last shift
    tms_pad_i<=#1 1;        // going out of shiftIR
    gen_clk(1);
    tdi_pad_i<=#1 'hz;    // tri-state
    gen_clk(1);
    tms_pad_i<=#1 0;
    gen_clk(1);       // we are in RunTestIdle
  end
endtask
 
 
// Reads the ID code
task read_id_code;
  output [31:0] code;
  reg    [31:0] code;
  begin
    $display("(%0t) Task read_id_code", $time);
    tms_pad_i<=#1 1;
    gen_clk(1);
    tms_pad_i<=#1 0;
    gen_clk(2);  // we are in shiftDR
 
    tdi_pad_i<=#1 0;
    gen_clk(31);
 
    tms_pad_i<=#1 1;        // going out of shiftIR
    gen_clk(1);
 
    code = in_data_le;
 
    tdi_pad_i<=#1 'hz; // tri-state
    gen_clk(1);
    tms_pad_i<=#1 0;
    gen_clk(1);       // we are in RunTestIdle
  end
endtask
 
 
// sets the selected scan chain and goes to the RunTestIdle state
task chain_select;
  input [3:0]  data;
  input        gen_crc_err;
  integer i;
 
  begin
    case (data)
      `CPU_DEBUG_CHAIN      : $display("(%0t) Task chain_select (CPU_DEBUG_CHAIN, gen_crc_err=%0d)", $time, gen_crc_err);
      `WISHBONE_DEBUG_CHAIN : $display("(%0t) Task chain_select (WISHBONE_DEBUG_CHAIN, gen_crc_err=%0d)", $time, gen_crc_err);
      default               : $display("(%0t) Task chain_select (ERROR!!! Unknown chain selected)", $time);
    endcase
 
    tms_pad_i<=#1 1;
    gen_clk(1);
    tms_pad_i<=#1 0;
    gen_clk(2);  // we are in shiftDR
 
    crc_out = 32'hffffffff; // Initialize outgoing CRC
    tdi_pad_i<=#1 1'b1; // chain_select bit
    calculate_crc(1'b1);
    gen_clk(1);
 
    for(i=0; i<`CHAIN_ID_LENGTH; i=i+1)
    begin
      tdi_pad_i<=#1 data[i];
      calculate_crc(data[i]);
      gen_clk(1);
    end
 
    for(i=31; i>=0; i=i-1)
    begin
      if (gen_crc_err & (i==0))  // Generate crc error at last crc bit
        tdi_pad_i<=#1 ~crc_out[i];   // error crc
      else
        tdi_pad_i<=#1 crc_out[i];    // ok crc
 
      gen_clk(1);
    end
 
    tdi_pad_i<=#1 'hz;  // tri-state
 
    crc_in = 32'hffffffff;  // Initialize incoming CRC
    gen_clk(`STATUS_LEN);   // Generating 4 clocks to read out status.
 
 
    for(i=0; i<`CRC_LEN -1; i=i+1)
      gen_clk(1);
 
    tms_pad_i<=#1 1;
    gen_clk(1);         // to exit1_dr
 
    if (~crc_match_in)
      begin
        $display("(%0t) Incoming CRC failed !!!", $time);
        $stop;
      end
 
    tms_pad_i<=#1 1;
    gen_clk(1);         // to update_dr
    tms_pad_i<=#1 0;
    gen_clk(1);         // to run_test_idle
  end
endtask   // chain_select
 
 
 
 
task debug_wishbone;
  input [2:0]   command;
  input         ready;
  input [31:0]  addr;
  input [15:0]  length;
  input         gen_crc_err;
  input [99:0]  text;
  integer i;
 
  begin
   $write("(%0t) Task debug_wishbone: ", $time);
 
    test_text = text;
 
    case (command)
      `WB_STATUS   : 
        begin
          $display("wb_status (gen_crc_err=%0d (%0s))", gen_crc_err, text);
          debug_wishbone_status(command, gen_crc_err);
          last_wb_cmd = `WB_STATUS;  last_wb_cmd_text = "WB_STATUS";
        end 
      `WB_READ8    :  
        begin
          $display("wb_read8 (adr=0x%0x, length=0x%0x, gen_crc_err=%0d (%0s))", addr, length, gen_crc_err, text);
          debug_wishbone_set_addr(command, addr, length, gen_crc_err);
          last_wb_cmd = `WB_READ8;  last_wb_cmd_text = "WB_READ8";
        end
      `WB_READ16   :  
        begin
          $display("wb_read16 (adr=0x%0x, length=0x%0x, gen_crc_err=%0d (%0s))", addr, length, gen_crc_err, text);
          debug_wishbone_set_addr(command, addr, length, gen_crc_err);
          last_wb_cmd = `WB_READ16;  last_wb_cmd_text = "WB_READ16";
        end
      `WB_READ32   :  
        begin
          $display("wb_read32 (adr=0x%0x, length=0x%0x, gen_crc_err=%0d (%0s))", addr, length, gen_crc_err, text);
          debug_wishbone_set_addr(command, addr, length, gen_crc_err);
          last_wb_cmd = `WB_READ32;  last_wb_cmd_text = "WB_READ32";
        end
      `WB_WRITE8   :  
        begin
          $display("wb_write8 (adr=0x%0x, length=0x%0x, gen_crc_err=%0d (%0s))", addr, length, gen_crc_err, text);
          debug_wishbone_set_addr(command, addr, length, gen_crc_err);
          last_wb_cmd = `WB_WRITE8;  last_wb_cmd_text = "WB_WRITE8";
        end
      `WB_WRITE16  :  
        begin
          $display("wb_write16 (adr=0x%0x, length=0x%0x, gen_crc_err=%0d (%0s))", addr, length, gen_crc_err, text);
          debug_wishbone_set_addr(command, addr, length, gen_crc_err);
          last_wb_cmd = `WB_WRITE16;  last_wb_cmd_text = "WB_WRITE16";
        end
      `WB_WRITE32  :  
        begin
          $display("wb_write32 (adr=0x%0x, length=0x%0x, gen_crc_err=%0d (%0s))", addr, length, gen_crc_err, text);
          debug_wishbone_set_addr(command, addr, length, gen_crc_err);
          last_wb_cmd = `WB_WRITE32;  last_wb_cmd_text = "WB_WRITE32";
        end
      `WB_GO       :  
        begin
          $display("wb_go, ready=%0d, gen_crc_err=%0d (%0s))", ready, gen_crc_err, text);
          debug_wishbone_go(command, ready, gen_crc_err);
//          $display("wb_go_tmp, gen_crc_err=0x%0x (%0s))", gen_crc_err, text);
//          debug_wishbone_go_tmp(command, crc);
          last_wb_cmd = `WB_GO;  last_wb_cmd_text = "WB_GO";
        end
    endcase
  end
endtask       // debug_wishbone
 
 
 
 
 
 
task debug_wishbone_set_addr;
  input [2:0]   command;
  input [31:0]  addr;
  input [15:0]  length;
  input         gen_crc_err;
  integer i;
 
  begin
    $display("(%0t) Task debug_wishbone_set_addr: ", $time);
 
    tms_pad_i<=#1 1;
    gen_clk(1);
    tms_pad_i<=#1 0;
    gen_clk(2);  // we are in shiftDR
 
    crc_out = 32'hffffffff; // Initialize outgoing CRC
 
    tdi_pad_i<=#1 1'b0; // chain_select bit = 0
    calculate_crc(1'b0);
    gen_clk(1);
 
    for(i=2; i>=0; i=i-1)
    begin
      tdi_pad_i<=#1 command[i]; // command
      calculate_crc(command[i]);
      gen_clk(1);
    end
 
    for(i=31; i>=0; i=i-1)       // address
    begin
      tdi_pad_i<=#1 addr[i];
      calculate_crc(addr[i]);
      gen_clk(1);
    end
 
    for(i=15; i>=0; i=i-1)       // length
    begin
      tdi_pad_i<=#1 length[i];
      calculate_crc(length[i]);
      gen_clk(1);
    end
 
    for(i=31; i>=0; i=i-1)
    begin
      if (gen_crc_err & (i==0))  // Generate crc error at last crc bit
        tdi_pad_i<=#1 ~crc_out[i];   // error crc
      else
        tdi_pad_i<=#1 crc_out[i];    // ok crc
 
      gen_clk(1);
    end
 
    tdi_pad_i<=#1 'hz;
 
    crc_in = 32'hffffffff;  // Initialize incoming CRC
    gen_clk(`STATUS_LEN);   // Generating 4 clocks to read out status.
 
    for(i=0; i<`CRC_LEN -1; i=i+1)  // Getting in the CRC
    begin
      gen_clk(1);
    end
 
    tms_pad_i<=#1 1;
    gen_clk(1);         // to exit1_dr
 
    if (~crc_match_in)
      begin
        $display("(%0t) Incoming CRC failed !!!", $time);
        $stop;
      end
 
    tms_pad_i<=#1 1;
    gen_clk(1);         // to update_dr
    tms_pad_i<=#1 0;
    gen_clk(1);         // to run_test_idle
  end
endtask       // debug_wishbone_set_addr
 
 
 
 
 
task debug_wishbone_status;
  input [2:0]   command;
  input         gen_crc_err;
  integer i;
 
  begin
    $display("(%0t) Task debug_wishbone_status: ", $time);
 
    tms_pad_i<=#1 1;
    gen_clk(1);
    tms_pad_i<=#1 0;
    gen_clk(2);  // we are in shiftDR
 
    crc_out = 32'hffffffff; // Initialize outgoing CRC
 
    tdi_pad_i<=#1 1'b0; // chain_select bit = 0
    calculate_crc(1'b0);
    gen_clk(1);
 
    for(i=2; i>=0; i=i-1)
    begin
      tdi_pad_i<=#1 command[i]; // command
      calculate_crc(command[i]);
      gen_clk(1);
    end
 
    for(i=31; i>=0; i=i-1)
    begin
      if (gen_crc_err & (i==0))  // Generate crc error at last crc bit
        tdi_pad_i<=#1 ~crc_out[i];   // error crc
      else
        tdi_pad_i<=#1 crc_out[i];    // ok crc
 
      gen_clk(1);
    end
 
    tdi_pad_i<=#1 1'hz;
 
    crc_in = 32'hffffffff;  // Initialize incoming CRC
 
    gen_clk(`STATUS_LEN);   // Generating 4 clocks to read out status.
 
    for(i=0; i<`CRC_LEN -1; i=i+1)  // Getting in the CRC
    begin
      gen_clk(1);
    end
 
    tms_pad_i<=#1 1;
    gen_clk(1);         // to exit1_dr
 
    if (~crc_match_in)
      begin
        $display("(%0t) Incoming CRC failed !!!", $time);
        $stop;
      end
 
    tms_pad_i<=#1 1;
    gen_clk(1);         // to update_dr
    tms_pad_i<=#1 0;
    gen_clk(1);         // to run_test_idle
  end
endtask       // debug_wishbone_status
 
 
 
 
task debug_wishbone_go;
  input [2:0]   command;
  input         wait_for_wb_ready;
  input         gen_crc_err;
  integer i;
  reg   [4:0]   bit_pointer;
  integer       word_pointer;
  reg  [31:0]   tmp_data;
 
  begin
    $display("(%0t) Task debug_wishbone_go (previous command was %0s): ", $time, last_wb_cmd_text);
    word_pointer = 0;
 
    tms_pad_i<=#1 1;
    gen_clk(1);
    tms_pad_i<=#1 0;
    gen_clk(2);  // we are in shiftDR
 
    crc_out = 32'hffffffff; // Initialize outgoing CRC
 
    tdi_pad_i<=#1 1'b0; // chain_select bit = 0
    calculate_crc(1'b0);
    gen_clk(1);
 
    for(i=2; i>=0; i=i-1)
    begin
      tdi_pad_i<=#1 command[i]; // command
      calculate_crc(command[i]);
      gen_clk(1);
    end
 
 
    if ((last_wb_cmd == `WB_WRITE8) | (last_wb_cmd == `WB_WRITE16) | (last_wb_cmd == `WB_WRITE32))  // When WB_WRITEx was previously activated, data needs to be shifted.
      begin
        for (i=0; i<(dbg_tb.i_dbg_top.i_dbg_wb.len << 3); i=i+1)
          begin
            tmp_data = wb_data[word_pointer];
            if ((!(i%32)) && (i>0))
              begin
                word_pointer = word_pointer + 1;
              end
            bit_pointer = 31-i[4:0];
            tdi_pad_i<=#1 tmp_data[bit_pointer];
            calculate_crc(tmp_data[bit_pointer]);
            gen_clk(1);
 
          end
      end
 
    for(i=31; i>=1; i=i-1)
    begin
      tdi_pad_i<=#1 crc_out[i];
      gen_clk(1);
    end
 
    if (gen_crc_err)  // Generate crc error at last crc bit
      tdi_pad_i<=#1 ~crc_out[0];   // error crc
    else
      tdi_pad_i<=#1 crc_out[0];    // ok crc
 
    if (wait_for_wb_ready)
      begin
        tms_pad_i<=#1 1;
        gen_clk(1);       // to exit1_dr. Last CRC is shifted on this clk
        tms_pad_i<=#1 0;
        gen_clk(1);       // to pause_dr
 
        #2;             // wait a bit for tdo to activate
        while (tdo)     // waiting for wb to send "ready"
        begin
          gen_clk(1);       // staying in pause_dr
        end
 
        tms_pad_i<=#1 1;
        gen_clk(1);       // to exit2_dr
        tms_pad_i<=#1 0;
        gen_clk(1);       // to shift_dr
      end
    else
      begin
        gen_clk(1);       // Last CRC is shifted on this clk
      end
 
 
    tdi_pad_i<=#1 1'hz;
    crc_in = 32'hffffffff;  // Initialize incoming CRC
 
    if ((last_wb_cmd == `WB_READ8) | (last_wb_cmd == `WB_READ16) | (last_wb_cmd == `WB_READ32))  // When WB_READx was previously activated, data needs to be shifted.
      begin
        $display("\t\tGenerating %0d clocks to read %0d data bytes.", dbg_tb.i_dbg_top.i_dbg_wb.data_cnt_limit, dbg_tb.i_dbg_top.i_dbg_wb.data_cnt_limit>>3);
        word_pointer = 0; // Reset pointer
        for (i=0; i<(dbg_tb.i_dbg_top.i_dbg_wb.data_cnt_limit); i=i+1)
          begin
            gen_clk(1);
            if (i[4:0] == 31)   // Latching data
              begin
                wb_data[word_pointer] = in_data_be;
                $display("\t\tin_data_be = 0x%x", in_data_be);
                word_pointer = word_pointer + 1;
              end
          end
      end
 
 
    gen_clk(`STATUS_LEN);   // Generating 4 clocks to read out status.
 
    for(i=0; i<`CRC_LEN -1; i=i+1)  // Getting in the CRC
    begin
      gen_clk(1);
    end
 
    tms_pad_i<=#1 1;
    gen_clk(1);         // to exit1_dr
 
    if (~crc_match_in)
      begin
        $display("(%0t) Incoming CRC failed !!!", $time);
        $stop;
      end
 
    tms_pad_i<=#1 1;
    gen_clk(1);         // to update_dr
    tms_pad_i<=#1 0;
    gen_clk(1);         // to run_test_idle
  end
endtask       // debug_wishbone_go
 
 
 
 
task debug_cpu;
  input [2:0]   command;
  input [31:0]  addr;
  input [31:0]  data;
  input         gen_crc_err;
  output [31:0] result;
  input [199:0]  text;
  integer i;
 
  begin
   $write("(%0t) Task debug_cpu: ", $time);
 
    test_text = text;
 
    case (command)
//      `WB_STATUS   : 
//        begin
//          $display("wb_status (gen_crc_err=%0d (%0s))", gen_crc_err, text);
//          debug_wishbone_status(command, gen_crc_err);
//          last_wb_cmd = `WB_STATUS;  last_wb_cmd_text = "WB_STATUS";
//        end 
      `CPU_READ_REG   :  
        begin
          $display("cpu_read_reg (adr=0x%0x, gen_crc_err=%0d (%0s))", addr, gen_crc_err, text);
          debug_cpu_set_addr(command, addr, gen_crc_err);
          last_wb_cmd = `CPU_READ_REG;  last_wb_cmd_text = "CPU_READ_REG";
        end
      `CPU_WRITE_REG  :  
        begin
          $display("cpu_write_reg (adr=0x%0x, gen_crc_err=%0d (%0s))", addr, gen_crc_err, text);
          debug_cpu_set_addr(command, addr, gen_crc_err);
          last_wb_cmd = `CPU_WRITE_REG;  last_wb_cmd_text = "CPU_WRITE_REG";
        end
      `CPU_READ8      :
        begin
          $display("cpu_read8 (adr=0x%0x, gen_crc_err=%0d (%0s))", addr, gen_crc_err, text);
          debug_cpu_set_addr(command, addr, gen_crc_err);
          last_wb_cmd = `CPU_READ8;  last_wb_cmd_text = "CPU_READ8";
        end
      `CPU_READ32     :
        begin
          $display("cpu_read32 (adr=0x%0x, gen_crc_err=%0d (%0s))", addr, gen_crc_err, text);
          debug_cpu_set_addr(command, addr, gen_crc_err);
          last_wb_cmd = `CPU_READ32;  last_wb_cmd_text = "CPU_READ32";
        end
      `CPU_WRITE8     :
        begin
          $display("cpu_write8 (adr=0x%0x, gen_crc_err=%0d (%0s))", addr, gen_crc_err, text);
          debug_cpu_set_addr(command, addr, gen_crc_err);
          last_wb_cmd = `CPU_WRITE8;  last_wb_cmd_text = "CPU_WRITE8";
        end
      `CPU_WRITE32    :
        begin
          $display("cpu_write32 (adr=0x%0x, gen_crc_err=%0d (%0s))", addr, gen_crc_err, text);
          debug_cpu_set_addr(command, addr, gen_crc_err);
          last_wb_cmd = `CPU_WRITE32;  last_wb_cmd_text = "CPU_WRITE32";
        end
      `CPU_GO         :
        begin
          $display("cpu_go, data = 0x%0x, gen_crc_err=%0d (%0s))", data, gen_crc_err, text);
          debug_cpu_go(command, data, gen_crc_err);
          last_wb_cmd = `CPU_GO;  last_wb_cmd_text = "CPU_GO";
        end
      default     :
        begin
          $display("\t\tERROR: Non-existing command while debugging %0s", gen_crc_err, text);
          $stop;
        end
    endcase
  end
endtask       // debug_cpu
 
 
 
task debug_cpu_set_addr;
  input [2:0]   command;
  input [31:0]  addr;
  input         gen_crc_err;
  integer i;
 
  begin
    $display("(%0t) Task debug_cpu_set_addr: ", $time);
 
    tms_pad_i<=#1 1;
    gen_clk(1);
    tms_pad_i<=#1 0;
    gen_clk(2);  // we are in shiftDR
 
    crc_out = 32'hffffffff; // Initialize outgoing CRC
 
    tdi_pad_i<=#1 1'b0; // chain_select bit = 0
    calculate_crc(1'b0);
    gen_clk(1);
 
    for(i=2; i>=0; i=i-1)
    begin
      tdi_pad_i<=#1 command[i]; // command
      calculate_crc(command[i]);
      gen_clk(1);
    end
 
    for(i=31; i>=0; i=i-1)       // address
    begin
      tdi_pad_i<=#1 addr[i];
      calculate_crc(addr[i]);
      gen_clk(1);
    end
 
    for(i=31; i>=0; i=i-1)
    begin
      if (gen_crc_err & (i==0))  // Generate crc error at last crc bit
        tdi_pad_i<=#1 ~crc_out[i];   // error crc
      else
        tdi_pad_i<=#1 crc_out[i];    // ok crc
 
      gen_clk(1);
    end
 
    tdi_pad_i<=#1 'hz;
 
    crc_in = 32'hffffffff;  // Initialize incoming CRC
    gen_clk(`STATUS_LEN);   // Generating 4 clocks to read out status.
 
    for(i=0; i<`CRC_LEN -1; i=i+1)  // Getting in the CRC
    begin
      gen_clk(1);
    end
 
    tms_pad_i<=#1 1;
    gen_clk(1);         // to exit1_dr
 
    if (~crc_match_in)
      begin
        $display("(%0t) Incoming CRC failed !!!", $time);
        $stop;
      end
 
    tms_pad_i<=#1 1;
    gen_clk(1);         // to update_dr
    tms_pad_i<=#1 0;
    gen_clk(1);         // to run_test_idle
  end
endtask       // debug_cpu_set_addr
 
 
 
 
task debug_cpu_go;
  input [2:0]   command;
  input [31:0]  data;
  input         gen_crc_err;
  integer i, len;
 
 
  begin
    $display("(%0t) Task debug_cpu_go (previous command was %0s): ", $time, last_wb_cmd_text);
 
    tms_pad_i<=#1 1;
    gen_clk(1);
    tms_pad_i<=#1 0;
    gen_clk(2);  // we are in shiftDR
 
    crc_out = 32'hffffffff; // Initialize outgoing CRC
    tdi_pad_i<=#1 1'b0; // chain_select bit = 0
    calculate_crc(1'b0);
    gen_clk(1);
 
    for(i=2; i>=0; i=i-1)
    begin
      tdi_pad_i<=#1 command[i]; // command
      calculate_crc(command[i]);
      gen_clk(1);
    end
 
 
    if (last_wb_cmd == `CPU_WRITE32)
      begin
        len = 31;
        $display("\t\tdata = 0x%x", data);
      end
    else if ((last_wb_cmd == `CPU_WRITE8) | (last_wb_cmd == `CPU_WRITE_REG))
      begin
        len = 7;
        $display("\t\tdata = 0x%x", data[7:0]);
      end
    else
      len = 0;
 
    if (len>0)  // When CPU_WRITEx was previously activated, data needs to be shifted.
      begin
        for (i=len; i>=0; i=i-1)
          begin
            tdi_pad_i<=#1 data[i];
            calculate_crc(data[i]);
            gen_clk(1);
          end
      end
 
    for(i=31; i>=0; i=i-1)
    begin
      if (gen_crc_err & (i==0))  // Generate crc error at last crc bit
        tdi_pad_i<=#1 ~crc_out[i];   // error crc
      else
        tdi_pad_i<=#1 crc_out[i];    // ok crc
 
      gen_clk(1);
    end
 
    tdi_pad_i<=#1 1'hz;
 
    crc_in = 32'hffffffff;  // Initialize incoming CRC
 
    if (last_wb_cmd == `CPU_READ32)
      len = 32;
    else if ((last_wb_cmd == `CPU_READ8) | (last_wb_cmd == `CPU_READ_REG))
      len = 8;
    else
      len = 0;
 
    if (len>0)    // When CPU_READx was previously activated, data needs to be shifted.
      begin
        $display("\t\tGenerating %0d clocks to read out the data.", len);
        for (i=0; i<len; i=i+1)
          gen_clk(1);
      end
 
 
    gen_clk(`STATUS_LEN);   // Generating 4 clocks to read out status.
 
    for(i=0; i<`CRC_LEN -1; i=i+1)  // Getting in the CRC
    begin
      gen_clk(1);
    end
 
    tms_pad_i<=#1 1;
    gen_clk(1);         // to exit1_dr
 
    if (~crc_match_in)
      begin
        $display("(%0t) Incoming CRC failed !!!", $time);
        $stop;
      end
 
    tms_pad_i<=#1 1;
    gen_clk(1);         // to update_dr
    tms_pad_i<=#1 0;
    gen_clk(1);         // to run_test_idle
  end
endtask       // debug_cpu_go
 
 
 
always @ (posedge tck_pad_i)
begin
  in_data_be[31:1] <= #1 in_data_be[30:0];
  in_data_be[0]    <= #1 tdo;
 
  in_data_le[31]   <= #1 tdo;
  in_data_le[30:0] <= #1 in_data_le[31:1];
end
 
 
 
// Calculating outgoing CRC
task calculate_crc;
  input data;
 
  begin
    crc_out[0]  <= #1 data          ^ crc_out[31];
    crc_out[1]  <= #1 data          ^ crc_out[0]  ^ crc_out[31];
    crc_out[2]  <= #1 data          ^ crc_out[1]  ^ crc_out[31];
    crc_out[3]  <= #1 crc_out[2];
    crc_out[4]  <= #1 data          ^ crc_out[3]  ^ crc_out[31];
    crc_out[5]  <= #1 data          ^ crc_out[4]  ^ crc_out[31];
    crc_out[6]  <= #1 crc_out[5];
    crc_out[7]  <= #1 data          ^ crc_out[6]  ^ crc_out[31];
    crc_out[8]  <= #1 data          ^ crc_out[7]  ^ crc_out[31];
    crc_out[9]  <= #1 crc_out[8];
    crc_out[10] <= #1 data         ^ crc_out[9]  ^ crc_out[31];
    crc_out[11] <= #1 data         ^ crc_out[10] ^ crc_out[31];
    crc_out[12] <= #1 data         ^ crc_out[11] ^ crc_out[31];
    crc_out[13] <= #1 crc_out[12];
    crc_out[14] <= #1 crc_out[13];
    crc_out[15] <= #1 crc_out[14];
    crc_out[16] <= #1 data         ^ crc_out[15] ^ crc_out[31];
    crc_out[17] <= #1 crc_out[16];
    crc_out[18] <= #1 crc_out[17];
    crc_out[19] <= #1 crc_out[18];
    crc_out[20] <= #1 crc_out[19];
    crc_out[21] <= #1 crc_out[20];
    crc_out[22] <= #1 data         ^ crc_out[21] ^ crc_out[31];
    crc_out[23] <= #1 data         ^ crc_out[22] ^ crc_out[31];
    crc_out[24] <= #1 crc_out[23];
    crc_out[25] <= #1 crc_out[24];
    crc_out[26] <= #1 data         ^ crc_out[25] ^ crc_out[31];
    crc_out[27] <= #1 crc_out[26];
    crc_out[28] <= #1 crc_out[27];
    crc_out[29] <= #1 crc_out[28];
    crc_out[30] <= #1 crc_out[29];
    crc_out[31] <= #1 crc_out[30];
  end
endtask // calculate_crc
 
 
// Calculating and checking input CRC
always @(posedge tck_pad_i)
begin
  crc_in[0]  <= #1 tdo           ^ crc_in[31];
  crc_in[1]  <= #1 tdo           ^ crc_in[0]  ^ crc_in[31];
  crc_in[2]  <= #1 tdo           ^ crc_in[1]  ^ crc_in[31];
  crc_in[3]  <= #1 crc_in[2];
  crc_in[4]  <= #1 tdo           ^ crc_in[3]  ^ crc_in[31];
  crc_in[5]  <= #1 tdo           ^ crc_in[4]  ^ crc_in[31];
  crc_in[6]  <= #1 crc_in[5];
  crc_in[7]  <= #1 tdo           ^ crc_in[6]  ^ crc_in[31];
  crc_in[8]  <= #1 tdo           ^ crc_in[7]  ^ crc_in[31];
  crc_in[9]  <= #1 crc_in[8];
  crc_in[10] <= #1 tdo          ^ crc_in[9]  ^ crc_in[31];
  crc_in[11] <= #1 tdo          ^ crc_in[10] ^ crc_in[31];
  crc_in[12] <= #1 tdo          ^ crc_in[11] ^ crc_in[31];
  crc_in[13] <= #1 crc_in[12];
  crc_in[14] <= #1 crc_in[13];
  crc_in[15] <= #1 crc_in[14];
  crc_in[16] <= #1 tdo          ^ crc_in[15] ^ crc_in[31];
  crc_in[17] <= #1 crc_in[16];
  crc_in[18] <= #1 crc_in[17];
  crc_in[19] <= #1 crc_in[18];
  crc_in[20] <= #1 crc_in[19];
  crc_in[21] <= #1 crc_in[20];
  crc_in[22] <= #1 tdo          ^ crc_in[21] ^ crc_in[31];
  crc_in[23] <= #1 tdo          ^ crc_in[22] ^ crc_in[31];
  crc_in[24] <= #1 crc_in[23];
  crc_in[25] <= #1 crc_in[24];
  crc_in[26] <= #1 tdo          ^ crc_in[25] ^ crc_in[31];
  crc_in[27] <= #1 crc_in[26];
  crc_in[28] <= #1 crc_in[27];
  crc_in[29] <= #1 crc_in[28];
  crc_in[30] <= #1 crc_in[29];
  crc_in[31] <= #1 crc_in[30];
end
 
assign crc_match_in = crc_in == 32'h0;
 
 
 
/**********************************************************************************
*                                                                                 *
*   Printing the information to the screen                                        *
*                                                                                 *
**********************************************************************************/
 
always @ (posedge tck_pad_i)
begin
  if(dbg_tb.i_tap_top.update_ir)
    case(dbg_tb.i_tap_top.jtag_ir[`IR_LENGTH-1:0])
      `EXTEST         : $display("\tInstruction EXTEST entered");
      `SAMPLE_PRELOAD : $display("\tInstruction SAMPLE_PRELOAD entered");
      `IDCODE         : $display("\tInstruction IDCODE entered");
      `MBIST          : $display("\tInstruction MBIST entered");
      `DEBUG          : $display("\tInstruction DEBUG entered");
      `BYPASS         : $display("\tInstruction BYPASS entered");
		default           :	$display("\n\tInstruction not valid. Instruction BYPASS activated !!!");
    endcase
end
 
 
 
// We never use following states: exit2_ir,  exit2_dr,  pause_ir or pause_dr
always @ (posedge tck_pad_i)
begin
  if(dbg_tb.i_tap_top.pause_ir | dbg_tb.i_tap_top.exit2_ir)
    begin
      $display("\n(%0t) ERROR: State pause_ir or exit2_ir detected.", $time);
      $display("(%0t) Simulation stopped !!!", $time);
      $stop;
    end
end
 
 
 
 
// Detecting CRC error
always @ (posedge dbg_tb.i_dbg_top.i_dbg_wb.crc_cnt_end or posedge dbg_tb.i_dbg_top.chain_latch_en or posedge dbg_tb.i_dbg_top.i_dbg_cpu.crc_cnt_end)
begin
  #2;
  if (~dbg_tb.i_dbg_top.crc_match)
    begin
      $display("\t\tCRC ERROR !!!");
      $stop;
    end
end
 
 
 
// Detecting errors in counters
always @ (dbg_tb.i_dbg_top.i_dbg_wb.cmd_cnt or 
          dbg_tb.i_dbg_top.i_dbg_wb.cmd_cnt_end or
          dbg_tb.i_dbg_top.i_dbg_wb.addr_len_cnt or
          dbg_tb.i_dbg_top.i_dbg_wb.addr_len_cnt_end or
          dbg_tb.i_dbg_top.i_dbg_wb.data_cnt or
          dbg_tb.i_dbg_top.i_dbg_wb.data_cnt_end or
          dbg_tb.i_dbg_top.i_dbg_wb.cmd_cnt_en or
          dbg_tb.i_dbg_top.i_dbg_wb.addr_len_cnt_en or
          dbg_tb.i_dbg_top.i_dbg_wb.data_cnt_en or
          dbg_tb.i_dbg_top.i_dbg_wb.crc_cnt_en or
          dbg_tb.i_dbg_top.i_dbg_wb.status_cnt1
          //dbg_tb.i_dbg_top.i_dbg_wb.status_cnt2 or
          //dbg_tb.i_dbg_top.i_dbg_wb.status_cnt3 or
          //dbg_tb.i_dbg_top.i_dbg_wb.status_cnt4
          // dbg_tb.i_dbg_top.i_dbg_wb. or
         )
begin
  if ((~dbg_tb.i_dbg_top.i_dbg_wb.cmd_cnt_end) & (
                                                  dbg_tb.i_dbg_top.i_dbg_wb.addr_len_cnt_en |
                                                  dbg_tb.i_dbg_top.i_dbg_wb.data_cnt_en     |
                                                  dbg_tb.i_dbg_top.i_dbg_wb.crc_cnt_en      |
                                                  dbg_tb.i_dbg_top.i_dbg_wb.status_cnt1
                                                 )
     )
    begin
      $display("\n\n\t\t(%0t) ERROR in counters !!!", $time);
      #10000;
      $stop;
    end
 
 
 
end
 
 
 
 
 
 
endmodule // dbg_tb
 
 
 

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