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+// Todo: Probably add in support for scheduling events (more than one as
+// well) on the case of the ROB being empty or full. Considering tracking
+// free entries instead of insts in ROB. Differentiate between squashing
+// all instructions after the instruction, and all instructions after *and*
+// including that instruction.
+
+#ifndef __CPU_BETA_CPU_ROB_HH__
+#define __CPU_BETA_CPU_ROB_HH__
+
+#include <utility>
+#include <vector>
+
+/**
+ * ROB class. Uses the instruction list that exists within the CPU to
+ * represent the ROB. This class doesn't contain that list, but instead
+ * a pointer to the CPU to get access to the list. The ROB, in this first
+ * implementation, is largely what drives squashing.
+ */
+template <class Impl>
+class ROB
+{
+ public:
+ //Typedefs from the Impl.
+ typedef typename Impl::FullCPU FullCPU;
+ typedef typename Impl::DynInstPtr DynInstPtr;
+
+ typedef std::pair<RegIndex, PhysRegIndex> UnmapInfo_t;
+ typedef typename list<DynInstPtr>::iterator InstIt_t;
+
+ public:
+ /** ROB constructor.
+ * @params _numEntries Number of entries in ROB.
+ * @params _squashWidth Number of instructions that can be squashed in a
+ * single cycle.
+ */
+ ROB(unsigned _numEntries, unsigned _squashWidth);
+
+ /** Function to set the CPU pointer, necessary due to which object the ROB
+ * is created within.
+ * @params cpu_ptr Pointer to the implementation specific full CPU object.
+ */
+ void setCPU(FullCPU *cpu_ptr);
+
+ /** Function to insert an instruction into the ROB. The parameter inst is
+ * not truly required, but is useful for checking correctness. Note
+ * that whatever calls this function must ensure that there is enough
+ * space within the ROB for the new instruction.
+ * @params inst The instruction being inserted into the ROB.
+ * @todo Remove the parameter once correctness is ensured.
+ */
+ 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() { return cpu->instList.front(); }
+
+ DynInstPtr readTailInst() { return (*tail); }
+
+ void retireHead();
+
+ bool isHeadReady();
+
+ unsigned numFreeEntries();
+
+ bool isFull()
+ { return numInstsInROB == numEntries; }
+
+ bool isEmpty()
+ { return numInstsInROB == 0; }
+
+ void doSquash();
+
+ void squash(InstSeqNum squash_num);
+
+ uint64_t readHeadPC();
+
+ uint64_t readHeadNextPC();
+
+ InstSeqNum readHeadSeqNum();
+
+ uint64_t readTailPC();
+
+ InstSeqNum readTailSeqNum();
+
+ /** Checks if the ROB is still in the process of squashing instructions.
+ * @retval Whether or not the ROB is done squashing.
+ */
+ bool isDoneSquashing() const { return doneSquashing; }
+
+ /** 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();
+
+ private:
+
+ /** Pointer to the CPU. */
+ FullCPU *cpu;
+
+ /** Number of instructions in the ROB. */
+ unsigned numEntries;
+
+ /** Number of instructions that can be squashed in a single cycle. */
+ unsigned squashWidth;
+
+ /** 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_t tail;
+
+ /** 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_t squashIt;
+
+ /** Number of instructions in the ROB. */
+ int numInstsInROB;
+
+ /** The sequence number of the squashed instruction. */
+ InstSeqNum squashedSeqNum;
+
+ /** Is the ROB done squashing. */
+ bool doneSquashing;
+};
+
+#endif //__CPU_BETA_CPU_ROB_HH__