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[/] [openrisc/] [trunk/] [orpsocv2/] [bench/] [sysc/] [src/] [TapActionIRScan.cpp] - Rev 178
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// ---------------------------------------------------------------------------- // TAP IR-Scan action: implementation // 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. // ---------------------------------------------------------------------------- // $Id$ #include "TapActionIRScan.h" #include "TapStateMachine.h" //! Constructor //! Sets up the superclass with the SystemC completion event and initializes //! our state as appropriate. //! @param[in] doneEvent SystemC event to be signalled when this action is //! complete. //! @param[in] _iRegIn The register to shift in. //! @param[in] _iRegSize Size in bits of the register to shift in. TapActionIRScan::TapActionIRScan (sc_core::sc_event *_doneEvent, uint32_t _iRegIn, int _iRegSize) : TapAction (_doneEvent), iRegIn (_iRegIn), iRegSize (_iRegSize), iRegOut (0), bitsShifted (0), iRScanState (SHIFT_IR_PREPARING) { } // TapActionIRScan () //! Process the Shift-IR action //! This drives the IR-Scan state. We can only do this if we have the TAP //! state machine in a consistent state, which in turn is only possible if we //! have been through a reset cycle. //! If the state machine shows it has yet to be through a reset cycle, we //! drive that cycle, after issuing a warning. This functionality is provided //! by the parent class, TapAction::. //! @param[in] tapStateMachine The TAP state machine with which this action //! is associated. //! @param[out] tdi The value to drive on TDI //! @param[in] tdo The value currently on TDO //! @param[out] tms The value to drive on TMS //! @return True if the action is complete bool TapActionIRScan::process (TapStateMachine *tapStateMachine, bool &tdi, bool tdo, bool &tms) { // Ensure we are in a consistent state. If not then we'll have moved towards // it and can return with the given tms if (!checkResetDone (tapStateMachine, tms, true)) { return false; } // We are consistent, so work through the IR-Scan process switch (iRScanState) { case SHIFT_IR_PREPARING: // Are we in the Shift-IR state yet? if (!tapStateMachine->targetState (TAP_SHIFT_IR, tms)) { return false; // Not there. Accept the TMS value } else { iRScanState = SHIFT_IR_SHIFTING; // Drop through } case SHIFT_IR_SHIFTING: // Are we still shifting stuff? if (bitsShifted < iRegSize) { // We are in the Shift-IR state. Another bit about to be done, so // increment the count bitsShifted++; // Shift out the TDI value from the bottom of the register tdi = iRegIn & 1; iRegIn >>= 1; // Record the TDO value. This is always a cycle late, so we ignore // it the first time. The value shifts in from the top. if (bitsShifted > 1) { iRegOut >>= 1; // Move all the existing bits right if (tdo) // OR any new bit in { uint32_t tmpBit = 1 << (iRegSize - 1); iRegOut |= tmpBit; } } // TMS is 0 to keep us here UNLESS this is the last bit, in which // case it is 1 to move us into Exit1-IR. tms = (bitsShifted == iRegSize); return false; } else { // Capture the last TDO bit iRegOut >>= 1; // Move all the existing bits right if (tdo) // OR any new bit in { uint32_t tmpBit = 1 << (iRegSize - 1); iRegOut |= tmpBit; } iRScanState = SHIFT_IR_UPDATING; // Drop through } case SHIFT_IR_UPDATING: // Are we still trying to update? if (!tapStateMachine->targetState (TAP_UPDATE_IR, tms)) { return false; // Not there. Accept the TMS value } else { return true; // All done } } } // process () //! Get the shifted out register //! @return The value of the shifted our register uint32_t TapActionIRScan::getIRegOut () { return iRegOut; } // getIRegOut ()
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