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Diffstat (limited to 'src/cpu/o3/rob.hh')
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1 files changed, 314 insertions, 0 deletions
diff --git a/src/cpu/o3/rob.hh b/src/cpu/o3/rob.hh new file mode 100644 index 000000000..e05eebe5a --- /dev/null +++ b/src/cpu/o3/rob.hh @@ -0,0 +1,314 @@ +/* + * Copyright (c) 2004-2006 The Regents of The University of Michigan + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer; + * redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution; + * neither the name of the copyright holders nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#ifndef __CPU_O3_ROB_HH__ +#define __CPU_O3_ROB_HH__ + +#include <string> +#include <utility> +#include <vector> + +/** + * ROB class. The ROB is largely what drives squashing. + */ +template <class Impl> +class ROB +{ + protected: + typedef TheISA::RegIndex RegIndex; + public: + //Typedefs from the Impl. + typedef typename Impl::FullCPU FullCPU; + typedef typename Impl::DynInstPtr DynInstPtr; + + typedef std::pair<RegIndex, PhysRegIndex> UnmapInfo; + typedef typename std::list<DynInstPtr>::iterator InstIt; + + /** Possible ROB statuses. */ + enum Status { + Running, + Idle, + ROBSquashing + }; + + /** SMT ROB Sharing Policy */ + enum ROBPolicy{ + Dynamic, + Partitioned, + Threshold + }; + + private: + /** Per-thread ROB status. */ + Status robStatus[Impl::MaxThreads]; + + /** ROB resource sharing policy for SMT mode. */ + ROBPolicy robPolicy; + + public: + /** ROB constructor. + * @param _numEntries Number of entries in ROB. + * @param _squashWidth Number of instructions that can be squashed in a + * single cycle. + * @param _smtROBPolicy ROB Partitioning Scheme for SMT. + * @param _smtROBThreshold Max Resources(by %) a thread can have in the ROB. + * @param _numThreads The number of active threads. + */ + ROB(unsigned _numEntries, unsigned _squashWidth, std::string smtROBPolicy, + unsigned _smtROBThreshold, unsigned _numThreads); + + std::string name() const; + + /** Function to set the CPU pointer, necessary due to which object the ROB + * is created within. + * @param cpu_ptr Pointer to the implementation specific full CPU object. + */ + void setCPU(FullCPU *cpu_ptr); + + /** Sets pointer to the list of active threads. + * @param at_ptr Pointer to the list of active threads. + */ + void setActiveThreads(std::list<unsigned>* at_ptr); + + void switchOut(); + + void takeOverFrom(); + + /** Function to insert an instruction into the ROB. Note that whatever + * calls this function must ensure that there is enough space within the + * ROB for the new instruction. + * @param inst The instruction being inserted into the ROB. + */ + void insertInst(DynInstPtr &inst); + + /** Returns pointer to the head instruction within the ROB. There is + * no guarantee as to the return value if the ROB is empty. + * @retval Pointer to the DynInst that is at the head of the ROB. + */ +// DynInstPtr readHeadInst(); + + /** Returns a pointer to the head instruction of a specific thread within + * the ROB. + * @return Pointer to the DynInst that is at the head of the ROB. + */ + DynInstPtr readHeadInst(unsigned tid); + + /** Returns pointer to the tail instruction within the ROB. There is + * no guarantee as to the return value if the ROB is empty. + * @retval Pointer to the DynInst that is at the tail of the ROB. + */ +// DynInstPtr readTailInst(); + + /** Returns a pointer to the tail instruction of a specific thread within + * the ROB. + * @return Pointer to the DynInst that is at the tail of the ROB. + */ + DynInstPtr readTailInst(unsigned tid); + + /** Retires the head instruction, removing it from the ROB. */ +// void retireHead(); + + /** Retires the head instruction of a specific thread, removing it from the + * ROB. + */ + void retireHead(unsigned tid); + + /** Is the oldest instruction across all threads ready. */ +// bool isHeadReady(); + + /** Is the oldest instruction across a particular thread ready. */ + bool isHeadReady(unsigned tid); + + /** Is there any commitable head instruction across all threads ready. */ + bool canCommit(); + + /** Re-adjust ROB partitioning. */ + void resetEntries(); + + /** Number of entries needed For 'num_threads' amount of threads. */ + int entryAmount(int num_threads); + + /** Returns the number of total free entries in the ROB. */ + unsigned numFreeEntries(); + + /** Returns the number of free entries in a specific ROB paritition. */ + unsigned numFreeEntries(unsigned tid); + + /** Returns the maximum number of entries for a specific thread. */ + unsigned getMaxEntries(unsigned tid) + { return maxEntries[tid]; } + + /** Returns the number of entries being used by a specific thread. */ + unsigned getThreadEntries(unsigned tid) + { return threadEntries[tid]; } + + /** Returns if the ROB is full. */ + bool isFull() + { return numInstsInROB == numEntries; } + + /** Returns if a specific thread's partition is full. */ + bool isFull(unsigned tid) + { return threadEntries[tid] == numEntries; } + + /** Returns if the ROB is empty. */ + bool isEmpty() + { return numInstsInROB == 0; } + + /** Returns if a specific thread's partition is empty. */ + bool isEmpty(unsigned tid) + { return threadEntries[tid] == 0; } + + /** Executes the squash, marking squashed instructions. */ + void doSquash(unsigned tid); + + /** Squashes all instructions younger than the given sequence number for + * the specific thread. + */ + void squash(InstSeqNum squash_num, unsigned tid); + + /** Updates the head instruction with the new oldest instruction. */ + void updateHead(); + + /** Updates the tail instruction with the new youngest instruction. */ + void updateTail(); + + /** Reads the PC of the oldest head instruction. */ +// uint64_t readHeadPC(); + + /** Reads the PC of the head instruction of a specific thread. */ +// uint64_t readHeadPC(unsigned tid); + + /** Reads the next PC of the oldest head instruction. */ +// uint64_t readHeadNextPC(); + + /** Reads the next PC of the head instruction of a specific thread. */ +// uint64_t readHeadNextPC(unsigned tid); + + /** Reads the sequence number of the oldest head instruction. */ +// InstSeqNum readHeadSeqNum(); + + /** Reads the sequence number of the head instruction of a specific thread. + */ +// InstSeqNum readHeadSeqNum(unsigned tid); + + /** Reads the PC of the youngest tail instruction. */ +// uint64_t readTailPC(); + + /** Reads the PC of the tail instruction of a specific thread. */ +// uint64_t readTailPC(unsigned tid); + + /** Reads the sequence number of the youngest tail instruction. */ +// InstSeqNum readTailSeqNum(); + + /** Reads the sequence number of tail instruction of a specific thread. */ +// InstSeqNum readTailSeqNum(unsigned tid); + + /** Checks if the ROB is still in the process of squashing instructions. + * @retval Whether or not the ROB is done squashing. + */ + bool isDoneSquashing(unsigned tid) const + { return doneSquashing[tid]; } + + /** Checks if the ROB is still in the process of squashing instructions for + * any thread. + */ + bool isDoneSquashing(); + + /** This is more of a debugging function than anything. Use + * numInstsInROB to get the instructions in the ROB unless you are + * double checking that variable. + */ + int countInsts(); + + /** This is more of a debugging function than anything. Use + * threadEntries to get the instructions in the ROB unless you are + * double checking that variable. + */ + int countInsts(unsigned tid); + + private: + /** Pointer to the CPU. */ + FullCPU *cpu; + + /** Active Threads in CPU */ + std::list<unsigned>* activeThreads; + + /** Number of instructions in the ROB. */ + unsigned numEntries; + + /** Entries Per Thread */ + unsigned threadEntries[Impl::MaxThreads]; + + /** Max Insts a Thread Can Have in the ROB */ + unsigned maxEntries[Impl::MaxThreads]; + + /** ROB List of Instructions */ + std::list<DynInstPtr> instList[Impl::MaxThreads]; + + /** Number of instructions that can be squashed in a single cycle. */ + unsigned squashWidth; + + public: + /** Iterator pointing to the instruction which is the last instruction + * in the ROB. This may at times be invalid (ie when the ROB is empty), + * however it should never be incorrect. + */ + InstIt tail; + + /** Iterator pointing to the instruction which is the first instruction in + * in the ROB*/ + InstIt head; + + private: + /** Iterator used for walking through the list of instructions when + * squashing. Used so that there is persistent state between cycles; + * when squashing, the instructions are marked as squashed but not + * immediately removed, meaning the tail iterator remains the same before + * and after a squash. + * This will always be set to cpu->instList.end() if it is invalid. + */ + InstIt squashIt[Impl::MaxThreads]; + + public: + /** Number of instructions in the ROB. */ + int numInstsInROB; + + DynInstPtr dummyInst; + + private: + /** The sequence number of the squashed instruction. */ + InstSeqNum squashedSeqNum; + + /** Is the ROB done squashing. */ + bool doneSquashing[Impl::MaxThreads]; + + /** Number of active threads. */ + unsigned numThreads; +}; + +#endif //__CPU_O3_ROB_HH__ |