src/arch/mips/isa.hh

/*
 * Copyright (c) 2009 The Regents of The University of Michigan
 * All rights reserved.
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 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
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 * 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
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#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();

        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(int misc_reg, ThreadID tid) { }
        RegVal readMiscRegNoEffect(int misc_reg, ThreadID tid = 0) const;

        //template <class TC>
        RegVal readMiscReg(int misc_reg, ThreadID tid = 0);

        RegVal filterCP0Write(int misc_reg, int reg_sel, RegVal val);
        void setRegMask(int misc_reg, RegVal val, ThreadID tid = 0);
        void setMiscRegNoEffect(int misc_reg, RegVal val, ThreadID tid=0);

        //template <class TC>
        void setMiscReg(int misc_reg, RegVal val, ThreadID tid=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[MISCREG_NUMREGS];

      public:
        ISA(const Params &p);

        RegId flattenRegId(const RegId& regId) const { return regId; }

        int flattenIntIndex(int reg) const { return reg; }
        int flattenFloatIndex(int reg) const { return reg; }
        int flattenVecIndex(int reg) const { return reg; }
        int flattenVecElemIndex(int reg) const { return reg; }
        int flattenVecPredIndex(int reg) const { return reg; }
        // dummy
        int flattenCCIndex(int reg) const { return reg; }
        int flattenMiscIndex(int reg) const { return reg; }

        bool
        inUserMode() const override
        {
            RegVal Stat = readMiscRegNoEffect(MISCREG_STATUS);
            RegVal Dbg = readMiscRegNoEffect(MISCREG_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