comm.hh

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/*
 * Copyright (c) 2011, 2016-2017 ARM Limited
 * Copyright (c) 2013 Advanced Micro Devices, Inc.
 * Copyright (c) 2022-2023 The University of Edinburgh
 * All rights reserved
 *
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 * property including but not limited to intellectual property relating
 * to a hardware implementation of the functionality of the software
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 * terms below provided that you ensure that this notice is replicated
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#ifndef __CPU_O3_COMM_HH__
#define __CPU_O3_COMM_HH__
 
#include <vector>
 
#include "arch/generic/pcstate.hh"
#include "base/types.hh"
#include "cpu/inst_seq.hh"
#include "cpu/o3/dyn_inst_ptr.hh"
#include "cpu/o3/limits.hh"
#include "sim/faults.hh"
 
namespace gem5
{
 
namespace o3
{

struct FetchStruct
{
    int size;
 
    DynInstPtr insts[MaxWidth];
    Fault fetchFault;
    InstSeqNum fetchFaultSN;
    bool clearFetchFault;
};

struct DecodeStruct
{
    int size;
 
    DynInstPtr insts[MaxWidth];
};

struct RenameStruct
{
    int size;
 
    DynInstPtr insts[MaxWidth];
};

struct IEWStruct
{
    int size;
 
    DynInstPtr insts[MaxWidth];
    DynInstPtr mispredictInst[MaxThreads];
    Addr mispredPC[MaxThreads];
    InstSeqNum squashedSeqNum[MaxThreads];
    std::unique_ptr<PCStateBase> pc[MaxThreads];
 
    bool squash[MaxThreads];
    bool branchMispredict[MaxThreads];
    bool branchTaken[MaxThreads];
    bool includeSquashInst[MaxThreads];
};
 
struct IssueStruct
{
    int size;
 
    DynInstPtr insts[MaxWidth];
};

struct TimeStruct
{
    struct FetchComm
    {
        bool block;
        bool squash;
        std::unique_ptr<PCStateBase> nextPC;
    };
 
    FetchComm fetchInfo[MaxThreads];
 
    struct DecodeComm
    {
        std::unique_ptr<PCStateBase> nextPC;
        DynInstPtr mispredictInst;
        DynInstPtr squashInst;
        InstSeqNum doneSeqNum = 0;
        Addr mispredPC = 0;
        uint64_t branchAddr = 0;
        unsigned branchCount = 0;
        bool squash = false;
        bool controlMispredict = false;
        bool branchMispredict = false;
        bool branchTaken = false;
    };
 
    DecodeComm decodeInfo[MaxThreads];
 
    struct RenameComm {};
 
    RenameComm renameInfo[MaxThreads];
 
    struct IewComm
    {
        // Also eventually include skid buffer space.
        unsigned freeIQEntries = 0;
        unsigned freeLQEntries = 0;
        unsigned freeSQEntries = 0;
        unsigned dispatchedToLQ = 0;
        unsigned dispatchedToSQ = 0;
 
        unsigned iqCount = 0;
        unsigned ldstqCount = 0;
 
        unsigned dispatched = 0;
        bool usedIQ = false;
        bool usedLSQ = false;
    };
 
    IewComm iewInfo[MaxThreads];
 
    struct CommitComm
    {
        // This code has been re-structured for better packing of variables
        // instead of by stage which is the more logical way to arrange the
        // data.
        // F = Fetch
        // D = Decode
        // I = IEW
        // R = Rename
        // As such each member is annotated with who consumes it
        // e.g. bool variable name // *F,R for Fetch and Rename

        std::unique_ptr<PCStateBase> pc; // *F

        DynInstPtr mispredictInst;  // *F

        DynInstPtr squashInst; // *F

        DynInstPtr strictlyOrderedLoad; // *I

        InstSeqNum nonSpecSeqNum = 0; // *I

        InstSeqNum doneSeqNum = 0; // *F, I

        unsigned freeROBEntries = 0; // *R
 
        bool squash = false; // *F, D, R, I
        bool robSquashing = false; // *F, D, R, I

        bool usedROB = false; // *R

        bool emptyROB = false; // *R

        bool branchTaken = false; // *F
        bool interruptPending = false; // *F
        bool clearInterrupt = false; // *F
        bool trapPending = false; // *F

        bool strictlyOrdered = false; // *I
 
    };
 
    CommitComm commitInfo[MaxThreads];
 
    bool decodeBlock[MaxThreads];
    bool decodeUnblock[MaxThreads];
    bool renameBlock[MaxThreads];
    bool renameUnblock[MaxThreads];
    bool iewBlock[MaxThreads];
    bool iewUnblock[MaxThreads];
};

template <class CommStruct>
void
removeCommThreadInsts(ThreadID tid, CommStruct& comm_struct)
{
    auto has_tid = [tid] (const auto &inst) -> bool {
        return inst && inst->threadNumber == tid;
    };
    DynInstPtr *last = std::remove_if(comm_struct.insts,
                                      comm_struct.insts + comm_struct.size,
                                      has_tid);
    std::fill(last, comm_struct.insts + comm_struct.size, nullptr);
    comm_struct.size = last - comm_struct.insts;
}
 
} // namespace o3
} // namespace gem5
 
#endif //__CPU_O3_COMM_HH__