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

// TAP DR-Scan action: definition

// Copyright (C) 2009  Embecosm Limited <info@embecosm.com>

// Contributor Jeremy Bennett <jeremy.bennett@embecosm.com>

// This file is part of the Embecosm cycle accurate SystemC JTAG library.

// This program 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 3 of the License, or (at your

// option) any later version.

// This program 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 program.  If not, see <http://www.gnu.org/licenses/>.

// The C/C++ parts of this program are commented throughout in a fashion

// suitable for processing with Doxygen.

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

// $Id$

#ifndef TAP_ACTION_DR_SCAN__H

#define TAP_ACTION_DR_SCAN__H

#include <stdint.h>

#include "TapAction.h"

#include "TapStateMachine.h"

//! Class to represent a TAP DR-Scan action.

//! JTAG data registers can be huge and are represented generically as arrays

//! of uint64_t. However for efficiency versions of methods are provided based

//! on a single uint64_t.

//! The SystemC classes for large unsigned ints are fabulously inefficient in

//! the reference implementation, so are not used here.

class TapActionDRScan

  : public TapAction

{

public:

  // Constructors and destructor

  TapActionDRScan (sc_core::sc_event *_doneEvent,

                   uint64_t           _dRegInArray[],

                   int                _dRegSize);

  TapActionDRScan (sc_core::sc_event *_doneEvent,

                   uint64_t           _dRegIn,

                   int                _dRegSize);

  TapActionDRScan (sc_core::sc_event *_doneEvent,

                   uint64_t           _dRegInArray[],

                   int                _dRegSize,

                   int                _goToPauseState,

                   int                _bitsBeforePauseState);

  TapActionDRScan (sc_core::sc_event *_doneEvent,

                   uint64_t           _dRegIn,

                   int                _dRegSize,

                   int                _goToPauseState,

                   int                _bitsBeforePauseState);

  ~TapActionDRScan ();

  // Get the shifted out value

  void      getDRegOut (uint64_t  dRegArray[]);

  uint64_t  getDRegOut ();

protected:

  // Process the action for IR-Scan

  bool  process (TapStateMachine *tapStateMachine,

                 bool            &tdi,

                 bool             tdo,

                 bool            &tms);

private:

  //! Number of bits in the data register

  int  dRegBitSize;

  //! Number of uint64_t words in the data register

  int  dRegWordSize;

  //! Mask for top word in multi-word register

  uint64_t  topMask;

  //! The value being shifted in

  uint64_t *dRegInArray;

  //! The value being shifted in (small version optimization)

  uint64_t  dRegIn;

  //! The value shifted out

  uint64_t *dRegOutArray;

  //! The value being shifted out (small version optimization)

  uint64_t  dRegOut;

  //! Should we go to PAUSE state and poll tdo during operation?

  int goToPauseState;

  //! Number of bits to shift before going to PAUSE state and polling tdo

  int bitsBeforePause;

  int pauseStateCount;

  //! Bits shifted so far

  int  bitsShifted;

  //! Where we are in the Shift-DR process

  enum {

    SHIFT_DR_PREPARING,

    SHIFT_DR_SHIFTING,

    SHIFT_DR_SHIFTING_BEFORE_PAUSE,

    SHIFT_DR_SHIFTING_PAUSE,

    SHIFT_DR_EXIT2,

    SHIFT_DR_SHIFTING_AFTER_PAUSE,

    SHIFT_DR_UPDATING

  } dRScanState;

  // Utilities to shift the bottom bit out and top bit in

  bool  shiftDRegOut ();

  void  shiftDRegIn (bool  bitIn);

};      // TapActionDRScan

#endif  // TAP_ACTION_DR_SCAN__H