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//----------------------------------------------------------------------

//   Copyright 2007-2011 Mentor Graphics Corporation

//   Copyright 2007-2010 Cadence Design Systems, Inc.

//   Copyright 2010 Synopsys, Inc.

//   Copyright 2013 Cisco Systems, Inc.

//   All Rights Reserved Worldwide

//

//   Licensed under the Apache License, Version 2.0 (the

//   "License"); you may not use this file except in

//   compliance with the License.  You may obtain a copy of

//   the License at

//

//       http://www.apache.org/licenses/LICENSE-2.0

//

//   Unless required by applicable law or agreed to in

//   writing, software distributed under the License is

//   distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR

//   CONDITIONS OF ANY KIND, either express or implied.  See

//   the License for the specific language governing

//   permissions and limitations under the License.

//----------------------------------------------------------------------

//------------------------------------------------------------------------------

//

// CLASS: uvm_sequence #(REQ,RSP)

//

// The uvm_sequence class provides the interfaces necessary in order to create

// streams of sequence items and/or other sequences.

//

//------------------------------------------------------------------------------

virtual class uvm_sequence #(type REQ = uvm_sequence_item,

                             type RSP = REQ) extends uvm_sequence_base;

  typedef uvm_sequencer_param_base #(REQ, RSP) sequencer_t;

  sequencer_t        param_sequencer;

  // Variable: req

  //

  // The sequence contains a field of the request type called req.  The user

  // can use this field, if desired, or create another field to use.  The

  // default ~do_print~ will print this field.

  REQ                req;

  // Variable: rsp

  //

  // The sequence contains a field of the response type called rsp.  The user

  // can use this field, if desired, or create another field to use.   The

  // default ~do_print~ will print this field.

  RSP                rsp;

  // Function: new

  //

  // Creates and initializes a new sequence object.

  function new (string name = "uvm_sequence");

    super.new(name);

  endfunction

  // Function: send_request

  //

  // This method will send the request item to the sequencer, which will forward

  // it to the driver.  If the rerandomize bit is set, the item will be

  // randomized before being sent to the driver. The send_request function may

  // only be called after  returns.

  function void send_request(uvm_sequence_item request, bit rerandomize = 0);

    REQ m_request;

    if (m_sequencer == null) begin

      uvm_report_fatal("SSENDREQ", "Null m_sequencer reference", UVM_NONE);

    end

    if (!$cast(m_request, request)) begin

      uvm_report_fatal("SSENDREQ", "Failure to cast uvm_sequence_item to request", UVM_NONE);

    end

    m_sequencer.send_request(this, m_request, rerandomize);

  endfunction

  // Function: get_current_item

  //

  // Returns the request item currently being executed by the sequencer. If the

  // sequencer is not currently executing an item, this method will return ~null~.

  //

  // The sequencer is executing an item from the time that get_next_item or peek

  // is called until the time that get or item_done is called.

  //

  // Note that a driver that only calls get will never show a current item,

  // since the item is completed at the same time as it is requested.

  function REQ get_current_item();

    if (!$cast(param_sequencer, m_sequencer))

      uvm_report_fatal("SGTCURR", "Failure to cast m_sequencer to the parameterized sequencer", UVM_NONE);

    return (param_sequencer.get_current_item());

  endfunction

  // Task: get_response

  //

  // By default, sequences must retrieve responses by calling get_response.

  // If no transaction_id is specified, this task will return the next response

  // sent to this sequence.  If no response is available in the response queue,

  // the method will block until a response is received.

  //

  // If a transaction_id is parameter is specified, the task will block until

  // a response with that transaction_id is received in the response queue.

  //

  // The default size of the response queue is 8.  The get_response method must

  // be called soon enough to avoid an overflow of the response queue to prevent

  // responses from being dropped.

  //

  // If a response is dropped in the response queue, an error will be reported

  // unless the error reporting is disabled via

  // set_response_queue_error_report_disabled.

  virtual task get_response(output RSP response, input int transaction_id = -1);

    uvm_sequence_item rsp;

    get_base_response( rsp, transaction_id);

    $cast(response,rsp);

  endtask

  // Function- put_response

  //

  // Internal method.

  virtual function void put_response(uvm_sequence_item response_item);

    RSP response;

    if (!$cast(response, response_item)) begin

      uvm_report_fatal("PUTRSP", "Failure to cast response in put_response", UVM_NONE);

    end

    put_base_response(response_item);

  endfunction

  // Function- do_print

  //

  function void do_print (uvm_printer printer);

    super.do_print(printer);

    printer.print_object("req", req);

    printer.print_object("rsp", rsp);

  endfunction

endclass