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[/] [openrisc/] [trunk/] [orpsocv2/] [bench/] [sysc/] [src/] [TapActionDRScan.cpp] - Rev 796
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// ---------------------------------------------------------------------------- // TAP DR-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 <iostream> #include <stdio.h> #include "TapActionDRScan.h" #include "TapStateMachine.h" //! Constructor for "large" DR registers //! Sets up the superclass with the SystemC completion event and initializes //! our state as appropriate. //! This constructor represents large registers as an array of uint64_t, with //! least significant bits in the lowest numbered element, and any odd bits in //! the highest numbered element. //! However if we are presented with an array that represents a "small" //! (i.e. up to 64-bit) register, we will store it efficiently. //! @param[in] doneEvent SystemC event to be signalled when this action is //! complete. //! @param[in] _dRegInArray The register to shift in. //! @param[in] _dRegSize Size in bits of the register to shift in. TapActionDRScan::TapActionDRScan(sc_core::sc_event * _doneEvent, uint64_t * _dRegInArray, int _dRegSize): TapAction(_doneEvent), dRegBitSize(_dRegSize), dRegWordSize((_dRegSize + 63) / 64), goToPauseState(0), bitsBeforePause(0), bitsShifted(0), dRScanState(SHIFT_DR_PREPARING) { // Small registers are represented simply. Large registers are copied to a // local instance (since we destroy dRegIn when shifting it) if (1 == dRegWordSize) { dRegIn = _dRegInArray[0]; dRegOut = 0; } else { dRegInArray = new uint64_t[dRegWordSize]; dRegOutArray = new uint64_t[dRegWordSize]; // Copy in the in array and zero the out array for (int i = 0; i < dRegWordSize; i++) { dRegInArray[i] = _dRegInArray[i]; dRegOutArray[i] = 0; } // Create a mask for the top word int maskBits = ((dRegBitSize - 1) % 64) + 1; topMask = (1ULL << maskBits) - 1ULL; } } // TapActionDRScan () //! Constructor for small DR registers //! Sets up the superclass with the SystemC completion event and initializes //! our state as appropriate. //! This constructor represents small registers in a single uint64_t //! @param[in] doneEvent SystemC event to be signalled when this action is //! complete. //! @param[in] _dRegIn The register to shift in. //! @param[in] _dRegSize Size in bits of the register to shift in. Must be no //! greater than 64, or we give a rude message and set //! the value to 64 anyway. TapActionDRScan::TapActionDRScan(sc_core::sc_event * _doneEvent, uint64_t _dRegIn, int _dRegSize):TapAction(_doneEvent), dRegBitSize(_dRegSize), dRegWordSize(1), goToPauseState(0), bitsBeforePause(0), bitsShifted(0), dRScanState(SHIFT_DR_PREPARING) { // Print a rude message if we are not small if (dRegBitSize > 64) { std::cerr << "Simple DR size reduced to 64 bits" << std::endl; dRegBitSize = 64; } // Simple representation dRegIn = _dRegIn; dRegOut = 0; } // TapActionDRScan () //! Constructor for "large" DR registers using special PAUSE state //! Sets up the superclass with the SystemC completion event and initializes //! our state as appropriate. //! This constructor represents large registers as an array of uint64_t, with //! least significant bits in the lowest numbered element, and any odd bits in //! the highest numbered element. //! However if we are presented with an array that represents a "small" //! (i.e. up to 64-bit) register, we will store it efficiently. //! @param[in] doneEvent SystemC event to be signalled when this action is //! complete. //! @param[in] _dRegInArray The register to shift in. //! @param[in] _dRegSize Size in bits of the register to shift in. //! @param[in] _goToPauseState Switch determining if we go to PAUSE state after _bitsBeforePauseState and poll for TDO=0 //! @param[in] _bitsBeforePauseState Number of bits to shift in before going to shift pause state and polling TDO, indicating transaction has completed TapActionDRScan::TapActionDRScan(sc_core::sc_event * _doneEvent, uint64_t * _dRegInArray, int _dRegSize, int _goToPauseState, int _bitsBeforePauseState):TapAction(_doneEvent), dRegBitSize(_dRegSize), dRegWordSize((_dRegSize + 63) / 64), goToPauseState(_goToPauseState), bitsBeforePause(_bitsBeforePauseState), pauseStateCount(0), bitsShifted(0), dRScanState(SHIFT_DR_PREPARING) { // Small registers are represented simply. Large registers are copied to a // local instance (since we destroy dRegIn when shifting it) if (1 == dRegWordSize) { dRegIn = _dRegInArray[0]; dRegOut = 0; } else { dRegInArray = new uint64_t[dRegWordSize]; dRegOutArray = new uint64_t[dRegWordSize]; // Copy in the in array and zero the out array for (int i = 0; i < dRegWordSize; i++) { dRegInArray[i] = _dRegInArray[i]; dRegOutArray[i] = 0; } // Create a mask for the top word int maskBits = ((dRegBitSize - 1) % 64) + 1; topMask = (1ULL << maskBits) - 1ULL; } } // TapActionDRScan () //! Constructor for small DR registers using special PAUSE state //! Sets up the superclass with the SystemC completion event and initializes //! our state as appropriate. //! This constructor represents small registers in a single uint64_t //! @param[in] doneEvent SystemC event to be signalled when this action is //! complete. //! @param[in] _dRegIn The register to shift in. //! @param[in] _dRegSize Size in bits of the register to shift in. Must be no //! greater than 64, or we give a rude message and set //! the value to 64 anyway. //! @param[in] _goToPauseState Switch determining if we go to PAUSE state after _bitsBeforePauseState and poll for TDO=0 //! @param[in] _bitsBeforePauseState Number of bits to shift in before going to shift pause state and polling TDO, indicating transaction has completed TapActionDRScan::TapActionDRScan(sc_core::sc_event * _doneEvent, uint64_t _dRegIn, int _dRegSize, int _goToPauseState, int _bitsBeforePauseState):TapAction(_doneEvent), dRegBitSize(_dRegSize), dRegWordSize(1), goToPauseState(_goToPauseState), bitsBeforePause(_bitsBeforePauseState), pauseStateCount(0), bitsShifted(0), dRScanState(SHIFT_DR_PREPARING) { // Print a rude message if we are not small if (dRegBitSize > 64) { std::cerr << "Simple DR size reduced to 64 bits" << std::endl; dRegBitSize = 64; } // Simple representation dRegIn = _dRegIn; dRegOut = 0; } // TapActionDRScan () //! Destructor. //! If we allocated them, free the large registers TapActionDRScan::~TapActionDRScan() { if (dRegWordSize > 1) { delete[]dRegInArray; delete[]dRegOutArray; } } // ~TapActionDRScan () //! Process the Shift-DR action //! This drives the DR-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 TapActionDRScan::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; } if (goToPauseState) { switch (dRScanState) { case SHIFT_DR_PREPARING: // Are we in the Shift-DR state yet? if (!tapStateMachine->targetState(TAP_SHIFT_DR, tms)) { return false; // Not there. Accept the TMS value } else { dRScanState = SHIFT_DR_SHIFTING_BEFORE_PAUSE; // Drop through } case SHIFT_DR_SHIFTING_BEFORE_PAUSE: // Are we still shifting stuff? if (bitsShifted < bitsBeforePause) { // We are in the Shift-DR state. Another bit about to be done, so // increment the count bitsShifted++; // Set the TDI value. In a routine to keep this tidy. tdi = shiftDRegOut(); // 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) { shiftDRegIn(tdo); } // TMS is 0 to keep us here UNLESS this is the last bit, in which case // it is 1 to move us into Exit1-DR. tms = (bitsShifted == bitsBeforePause); // Not done until we've updated return false; } else { // Capture the last TDO bit shiftDRegIn(tdo); // Now lower TMS to go to PAUSE_DR tms = false; dRScanState = SHIFT_DR_SHIFTING_PAUSE; } case SHIFT_DR_SHIFTING_PAUSE: { if (!tapStateMachine->targetState (TAP_PAUSE_DR, tms)) { return false; // Not there. Accept the TMS value } if (pauseStateCount++ < 3) return false; // Sit in DR_PAUSE state and cycle until TDO is low // tms starts false, should get set to true on the cycle // tdo goes low, then the next cycle we go back to SHIFT_DR // and we return so tms isn't set again. if (!tdo) { tms = true; dRScanState = SHIFT_DR_EXIT2; return false; } } case SHIFT_DR_EXIT2: { tms = false; shiftDRegIn(0); dRScanState = SHIFT_DR_SHIFTING_AFTER_PAUSE; return false; } case SHIFT_DR_SHIFTING_AFTER_PAUSE: { if (bitsShifted < dRegBitSize) { // We are in the Shift-DR state. Another bit about to be done, so // increment the count bitsShifted++; // Set the TDI value. In a routine to keep this tidy. tdi = shiftDRegOut(); //printf("shifting after pause (%d+32=%d) %d of %d tdo=%d\n",bitsBeforePause,bitsBeforePause+32, bitsShifted, dRegBitSize,(tdo) ? 1 : 0); shiftDRegIn(tdo); // TMS is 0 to keep us here UNLESS this is the last bit, in which case // it is 1 to move us into Exit1-DR. tms = (bitsShifted == dRegBitSize); // Not done until we've updated return false; } else { // Capture the last TDO bit shiftDRegIn(tdo); dRScanState = SHIFT_DR_UPDATING; // Drop through } } case SHIFT_DR_UPDATING: // Are we still trying to update? if (!tapStateMachine->targetState(TAP_UPDATE_DR, tms)) { return false; // Not there. Accept the TMS value } else { return true; // All done } } } else { switch (dRScanState) { case SHIFT_DR_PREPARING: // Are we in the Shift-DR state yet? if (!tapStateMachine->targetState(TAP_SHIFT_DR, tms)) { return false; // Not there. Accept the TMS value } else { dRScanState = SHIFT_DR_SHIFTING; // Drop through } case SHIFT_DR_SHIFTING: // Are we still shifting stuff? if (bitsShifted < dRegBitSize) { // We are in the Shift-DR state. Another bit about to be done, so // increment the count bitsShifted++; // Set the TDI value. In a routine to keep this tidy. tdi = shiftDRegOut(); // 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) { shiftDRegIn(tdo); } // TMS is 0 to keep us here UNLESS this is the last bit, in which case // it is 1 to move us into Exit1-DR. tms = (bitsShifted == dRegBitSize); // Not done until we've updated return false; } else { // Capture the last TDO bit shiftDRegIn(tdo); dRScanState = SHIFT_DR_UPDATING; // Drop through } case SHIFT_DR_UPDATING: // Are we still trying to update? if (!tapStateMachine->targetState(TAP_UPDATE_DR, tms)) { return false; // Not there. Accept the TMS value } else { return true; // All done } } } } // process () //! Get the shifted out value. //! This version works with large values. //! @param[out] dRegArray Array for the result void TapActionDRScan::getDRegOut(uint64_t dRegArray[]) { if (1 == dRegWordSize) { dRegArray[0] = dRegOut; } else { for (int i = 0; i < dRegWordSize; i++) { dRegArray[i] = dRegOutArray[i]; } } } // getDRegOut () //! Get the shifted out value. //! This version is for small values. For large values it silently returns the //! bottom 64 bits only. //! @todo Should we give an error. Or is it useful to allow efficient access //! to the bottom 64 bits? //! @return The value shifted out (or the bottom 64 bits thereof if the //! register is "large"). uint64_t TapActionDRScan::getDRegOut() { if (1 == dRegWordSize) { return dRegOut; } else { return dRegOutArray[0]; } } // getDRegOut () //! Utility to shift the bottom bit out of the dReg. //! Two flavours depending on whether we have a "small" register //! @return The bit shifted out. bool TapActionDRScan::shiftDRegOut() { if (1 == dRegWordSize) // "Small" register { bool res = dRegIn & 1; dRegIn >>= 1; return res; } else // "Large" register { bool res = (dRegInArray[0] & 1) == 1; // Shift all but the first word along for (int i = 0; i < (dRegWordSize - 1); i++) { dRegInArray[i] = (dRegInArray[i] >> 1) | (dRegInArray[i + 1] << 63); } // Shift the first word dRegInArray[dRegWordSize - 1] >>= 1; return res; } } // shiftDRegOut () //! Utility to shift the top bit into the dReg. //! Two flavours depending on whether we have a "small" register //! @param bitIn The bit to shift in the top void TapActionDRScan::shiftDRegIn(bool bitIn) { if (1 == dRegWordSize) // "Small" register { dRegOut >>= 1; // Move all the existing bits right if (bitIn) // OR any new bit in { uint64_t tmpBit = 1ULL << (dRegBitSize - 1); dRegOut |= tmpBit; } } else // "Large" register { // Shift all but the first word along for (int i = 0; i < (dRegWordSize - 1); i++) { dRegOutArray[i] >>= 1; dRegOutArray[i] |= dRegOutArray[i + 1] << 63; } // The first word is shifted and the new bit masked in dRegOutArray[dRegWordSize - 1] >>= 1; dRegOutArray[dRegWordSize - 1] |= bitIn ? (topMask + 1) >> 1 : 0; } } // shiftDRegIn ()
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