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authorKevin Lim <ktlim@umich.edu>2004-08-20 14:54:07 -0400
committerKevin Lim <ktlim@umich.edu>2004-08-20 14:54:07 -0400
commit04745696b6b523c5e90c335298099600d4a14a76 (patch)
tree66b578f8c44355ccf8e970fe59b52554dde9d0ce /cpu/beta_cpu/rob.hh
parent8295a8050c1096dc560f4976724adada810e56e1 (diff)
downloadgem5-04745696b6b523c5e90c335298099600d4a14a76.tar.xz
Check in of new CPU. This checkin works under non-Fullsystem mode, with no caches.
SConscript: Added new CPU files to build. arch/alpha/isa_desc: Changed rduniq and wruniq to be nonspeculative because the uniq register is not renamed. arch/isa_parser.py: Added new CPU exec method. base/statistics.hh: Minor change for namespace conflict. Probably can change back one the new CPU files are cleaned up. base/traceflags.py: Added new CPU trace flags. cpu/static_inst.hh: Changed static inst to use a file that defines the execute functions. --HG-- extra : convert_revision : bd4ce34361308280168324817fc1258dd253e519
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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 __ROB_HH__
+#define __ROB_HH__
+
+#include<utility>
+#include<vector>
+
+#include "arch/alpha/isa_traits.hh"
+
+using namespace std;
+
+/**
+ * ROB class. Uses the instruction list that exists within the CPU to
+ * represent the ROB. This class doesn't contain that structure, but instead
+ * a pointer to the CPU to get access to the structure. The ROB has a large
+ * hand in squashing instructions within the CPU, and is responsible for
+ * sending out the squash signal as well as what instruction is to be
+ * squashed. The ROB also controls most of the calls to the CPU to delete
+ * instructions; the only other call is made in the first stage of the pipe-
+ * line, which tells the CPU to delete all instructions not in the ROB.
+ */
+template<class Impl>
+class ROB
+{
+ public:
+ //Typedefs from the Impl.
+ typedef typename Impl::FullCPU FullCPU;
+ typedef typename Impl::DynInst DynInst;
+
+ typedef pair<RegIndex, PhysRegIndex> UnmapInfo;
+ typedef typename list<DynInst *>::iterator InstIt;
+
+ 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(DynInst *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.
+ */
+ DynInst *readHeadInst() { return cpu->instList.front(); }
+
+ DynInst *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;
+
+ unsigned numEntries;
+
+ /** Number of instructions that can be squashed in a single cycle. */
+ unsigned squashWidth;
+
+ InstIt tail;
+
+ InstIt squashIt;
+
+ int numInstsInROB;
+
+ /** The sequence number of the squashed instruction. */
+ InstSeqNum squashedSeqNum;
+
+ /** Is the ROB done squashing. */
+ bool doneSquashing;
+};
+
+#endif //__ROB_HH__