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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