/*
 * Copyright (c) 2009 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 __ARCH_MIPS_ISA_HH__
#define __ARCH_MIPS_ISA_HH__

#include <queue>
#include <string>
#include <vector>

#include "arch/generic/isa.hh"
#include "arch/mips/pcstate.hh"
#include "arch/mips/regs/misc.hh"
#include "arch/mips/types.hh"
#include "base/types.hh"
#include "cpu/reg_class.hh"
#include "sim/eventq.hh"
#include "sim/sim_object.hh"

namespace gem5
{

class BaseCPU;
class Checkpoint;
struct MipsISAParams;
class ThreadContext;

namespace MipsISA
{
    class ISA : public BaseISA
    {
      public:
        // The MIPS name for this file is CP0 or Coprocessor 0
        typedef ISA CP0;

        using Params = MipsISAParams;

      protected:
        // Number of threads and vpes an individual ISA state can handle
        uint8_t numThreads;
        uint8_t numVpes;

        enum BankType
        {
            perProcessor,
            perThreadContext,
            perVirtProcessor
        };

        std::vector<std::vector<RegVal> > miscRegFile;
        std::vector<std::vector<RegVal> > miscRegFile_WriteMask;
        std::vector<BankType> bankType;

      public:
        void clear() override;

        PCStateBase *
        newPCState(Addr new_inst_addr=0) const override
        {
            return new PCState(new_inst_addr);
        }

      public:
        void configCP();

        unsigned getVPENum(ThreadID tid) const;

        //////////////////////////////////////////////////////////
        //
        // READ/WRITE CP0 STATE
        //
        //
        //////////////////////////////////////////////////////////
        //@TODO: MIPS MT's register view automatically connects
        //       Status to TCStatus depending on current thread
        void updateCP0ReadView(RegIndex idx, ThreadID tid) { }
        RegVal readMiscRegNoEffect(RegIndex idx, ThreadID tid) const;
        RegVal
        readMiscRegNoEffect(RegIndex idx) const override
        {
            return readMiscRegNoEffect(idx, 0);
        }

        RegVal readMiscReg(RegIndex idx, ThreadID tid);
        RegVal
        readMiscReg(RegIndex idx) override
        {
            return readMiscReg(idx, 0);
        }

        RegVal filterCP0Write(RegIndex idx, int reg_sel, RegVal val);
        void setRegMask(RegIndex idx, RegVal val, ThreadID tid = 0);

        void setMiscRegNoEffect(RegIndex idx, RegVal val, ThreadID tid);
        void
        setMiscRegNoEffect(RegIndex idx, RegVal val) override
        {
            setMiscRegNoEffect(idx, val, 0);
        }

        void setMiscReg(RegIndex idx, RegVal val, ThreadID tid);
        void
        setMiscReg(RegIndex idx, RegVal val) override
        {
            setMiscReg(idx, val, 0);
        }

        //////////////////////////////////////////////////////////
        //
        // DECLARE INTERFACE THAT WILL ALLOW A MiscRegFile (Cop0)
        // TO SCHEDULE EVENTS
        //
        //////////////////////////////////////////////////////////

        // Flag that is set when CP0 state has been written to.
        bool cp0Updated;

        // Enumerated List of CP0 Event Types
        enum CP0EventType
        {
            UpdateCP0
        };

        /** Process a CP0 event */
        void processCP0Event(BaseCPU *cpu, CP0EventType);

        // Schedule a CP0 Update Event
        void scheduleCP0Update(BaseCPU *cpu, Cycles delay = Cycles(0));

        // If any changes have been made, then check the state for changes
        // and if necessary alert the CPU
        void updateCPU(BaseCPU *cpu);

        static std::string miscRegNames[misc_reg::NumRegs];

      public:
        ISA(const Params &p);

        bool
        inUserMode() const override
        {
            RegVal Stat = readMiscRegNoEffect(misc_reg::Status);
            RegVal Dbg = readMiscRegNoEffect(misc_reg::Debug);

            if (// EXL, ERL or CU0 set, CP0 accessible
                (Stat & 0x10000006) == 0 &&
                // DM bit set, CP0 accessible
                (Dbg & 0x40000000) == 0 &&
                // KSU = 0, kernel mode is base mode
                (Stat & 0x00000018) != 0) {
                // Unable to use Status_CU0, etc directly,
                // using bitfields & masks.
                return true;
            } else {
                return false;
            }
        }

        void copyRegsFrom(ThreadContext *src) override;
    };
} // namespace MipsISA
} // namespace gem5

#endif