/*
 * Copyright (c) 2016 RISC-V Foundation
 * Copyright (c) 2016 The University of Virginia
 * 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.
 *
 * Authors: Alec Roelke
 */
#include "arch/riscv/isa.hh"

#include <ctime>
#include <set>
#include <sstream>

#include "arch/riscv/registers.hh"
#include "base/bitfield.hh"
#include "cpu/base.hh"
#include "debug/RiscvMisc.hh"
#include "params/RiscvISA.hh"
#include "sim/core.hh"
#include "sim/pseudo_inst.hh"

namespace RiscvISA
{

ISA::ISA(Params *p) : SimObject(p)
{
    miscRegNames = {
        {MISCREG_USTATUS, "ustatus"},
        {MISCREG_UIE, "uie"},
        {MISCREG_UTVEC, "utvec"},
        {MISCREG_USCRATCH, "uscratch"},
        {MISCREG_UEPC, "uepc"},
        {MISCREG_UCAUSE, "ucause"},
        {MISCREG_UBADADDR, "ubadaddr"},
        {MISCREG_UIP, "uip"},
        {MISCREG_FFLAGS, "fflags"},
        {MISCREG_FRM, "frm"},
        {MISCREG_FCSR, "fcsr"},
        {MISCREG_CYCLE, "cycle"},
        {MISCREG_TIME, "time"},
        {MISCREG_INSTRET, "instret"},
        {MISCREG_CYCLEH, "cycleh"},
        {MISCREG_TIMEH, "timeh"},
        {MISCREG_INSTRETH, "instreth"},

        {MISCREG_SSTATUS, "sstatus"},
        {MISCREG_SEDELEG, "sedeleg"},
        {MISCREG_SIDELEG, "sideleg"},
        {MISCREG_SIE, "sie"},
        {MISCREG_STVEC, "stvec"},
        {MISCREG_SSCRATCH, "sscratch"},
        {MISCREG_SEPC, "sepc"},
        {MISCREG_SCAUSE, "scause"},
        {MISCREG_SBADADDR, "sbadaddr"},
        {MISCREG_SIP, "sip"},
        {MISCREG_SPTBR, "sptbr"},

        {MISCREG_HSTATUS, "hstatus"},
        {MISCREG_HEDELEG, "hedeleg"},
        {MISCREG_HIDELEG, "hideleg"},
        {MISCREG_HIE, "hie"},
        {MISCREG_HTVEC, "htvec"},
        {MISCREG_HSCRATCH, "hscratch"},
        {MISCREG_HEPC, "hepc"},
        {MISCREG_HCAUSE, "hcause"},
        {MISCREG_HBADADDR, "hbadaddr"},
        {MISCREG_HIP, "hip"},

        {MISCREG_MVENDORID, "mvendorid"},
        {MISCREG_MARCHID, "marchid"},
        {MISCREG_MIMPID, "mimpid"},
        {MISCREG_MHARTID, "mhartid"},
        {MISCREG_MSTATUS, "mstatus"},
        {MISCREG_MISA, "misa"},
        {MISCREG_MEDELEG, "medeleg"},
        {MISCREG_MIDELEG, "mideleg"},
        {MISCREG_MIE, "mie"},
        {MISCREG_MTVEC, "mtvec"},
        {MISCREG_MSCRATCH, "mscratch"},
        {MISCREG_MEPC, "mepc"},
        {MISCREG_MCAUSE, "mcause"},
        {MISCREG_MBADADDR, "mbadaddr"},
        {MISCREG_MIP, "mip"},
        {MISCREG_MBASE, "mbase"},
        {MISCREG_MBOUND, "mbound"},
        {MISCREG_MIBASE, "mibase"},
        {MISCREG_MIBOUND, "mibound"},
        {MISCREG_MDBASE, "mdbase"},
        {MISCREG_MDBOUND, "mdbound"},
        {MISCREG_MCYCLE, "mcycle"},
        {MISCREG_MINSTRET, "minstret"},
        {MISCREG_MUCOUNTEREN, "mucounteren"},
        {MISCREG_MSCOUNTEREN, "mscounteren"},
        {MISCREG_MHCOUNTEREN, "mhcounteren"},

        {MISCREG_TSELECT, "tselect"},
        {MISCREG_TDATA1, "tdata1"},
        {MISCREG_TDATA2, "tdata2"},
        {MISCREG_TDATA3, "tdata3"},
        {MISCREG_DCSR, "dcsr"},
        {MISCREG_DPC, "dpc"},
        {MISCREG_DSCRATCH, "dscratch"}
    };
    for (int i = 0; i < NumHpmcounter; i++)
    {
        int hpmcounter = MISCREG_HPMCOUNTER_BASE + i;
        std::stringstream ss;
        ss << "hpmcounter" << hpmcounter;
        miscRegNames[hpmcounter] = ss.str();
    }
    for (int i = 0; i < NumHpmcounterh; i++)
    {
        int hpmcounterh = MISCREG_HPMCOUNTERH_BASE + i;
        std::stringstream ss;
        ss << "hpmcounterh" << hpmcounterh;
        miscRegNames[hpmcounterh] = ss.str();
    }
    for (int i = 0; i < NumMhpmcounter; i++)
    {
        int mhpmcounter = MISCREG_MHPMCOUNTER_BASE + i;
        std::stringstream ss;
        ss << "mhpmcounter" << mhpmcounter;
        miscRegNames[mhpmcounter] = ss.str();
    }
    for (int i = 0; i < NumMhpmevent; i++)
    {
        int mhpmevent = MISCREG_MHPMEVENT_BASE + i;
        std::stringstream ss;
        ss << "mhpmcounterh" << mhpmevent;
        miscRegNames[mhpmevent] = ss.str();
    }

    miscRegFile.resize(NumMiscRegs);
    clear();
}

const RiscvISAParams *
ISA::params() const
{
    return dynamic_cast<const Params *>(_params);
}

void ISA::clear()
{
    std::fill(miscRegFile.begin(), miscRegFile.end(), 0);

    miscRegFile[MISCREG_MVENDORID] = 0;
    miscRegFile[MISCREG_MARCHID] = 0;
    miscRegFile[MISCREG_MIMPID] = 0;
    miscRegFile[MISCREG_MISA] = 0x8000000000101129ULL;
}


MiscReg
ISA::readMiscRegNoEffect(int misc_reg) const
{
    DPRINTF(RiscvMisc, "Reading CSR %s (0x%016llx).\n",
        miscRegNames.at(misc_reg), miscRegFile[misc_reg]);
    switch (misc_reg) {
      case MISCREG_FFLAGS:
        return bits(miscRegFile[MISCREG_FCSR], 4, 0);
      case MISCREG_FRM:
        return bits(miscRegFile[MISCREG_FCSR], 7, 5);
      case MISCREG_FCSR:
        return bits(miscRegFile[MISCREG_FCSR], 31, 0);
      case MISCREG_CYCLE:
        warn("Use readMiscReg to read the cycle CSR.");
        return 0;
      case MISCREG_TIME:
        return std::time(nullptr);
      case MISCREG_INSTRET:
        warn("Use readMiscReg to read the instret CSR.");
        return 0;
      case MISCREG_CYCLEH:
        warn("Use readMiscReg to read the cycleh CSR.");
        return 0;
      case MISCREG_TIMEH:
        return std::time(nullptr) >> 32;
      case MISCREG_INSTRETH:
        warn("Use readMiscReg to read the instreth CSR.");
        return 0;
      case MISCREG_MHARTID:
        warn("Use readMiscReg to read the mhartid CSR.");
        return 0;
      default:
        return miscRegFile[misc_reg];
    }
}

MiscReg
ISA::readMiscReg(int misc_reg, ThreadContext *tc)
{
    switch (misc_reg) {
      case MISCREG_INSTRET:
        DPRINTF(RiscvMisc, "Reading CSR %s (0x%016llx).\n",
            miscRegNames[misc_reg], miscRegFile[misc_reg]);
        return tc->getCpuPtr()->totalInsts();
      case MISCREG_CYCLE:
        DPRINTF(RiscvMisc, "Reading CSR %s (0x%016llx).\n",
            miscRegNames[misc_reg], miscRegFile[misc_reg]);
        return tc->getCpuPtr()->curCycle();
      case MISCREG_INSTRETH:
        DPRINTF(RiscvMisc, "Reading CSR %s (0x%016llx).\n",
            miscRegNames[misc_reg], miscRegFile[misc_reg]);
        return tc->getCpuPtr()->totalInsts() >> 32;
      case MISCREG_CYCLEH:
        DPRINTF(RiscvMisc, "Reading CSR %s (0x%016llx).\n",
            miscRegNames[misc_reg], miscRegFile[misc_reg]);
        return tc->getCpuPtr()->curCycle() >> 32;
      case MISCREG_MHARTID:
        return 0; // TODO: make this the hardware thread or cpu id
      default:
        return readMiscRegNoEffect(misc_reg);
    }
}

void
ISA::setMiscRegNoEffect(int misc_reg, const MiscReg &val)
{
    DPRINTF(RiscvMisc, "Setting CSR %s to 0x%016llx.\n",
        miscRegNames[misc_reg], val);
    switch (misc_reg) {
      case MISCREG_FFLAGS:
        miscRegFile[MISCREG_FCSR] &= ~0x1F;
        miscRegFile[MISCREG_FCSR] |= bits(val, 4, 0);
        break;
      case MISCREG_FRM:
        miscRegFile[MISCREG_FCSR] &= ~0x70;
        miscRegFile[MISCREG_FCSR] |= bits(val, 2, 0) << 5;
        break;
      case MISCREG_FCSR:
        miscRegFile[MISCREG_FCSR] = bits(val, 7, 0);
        break;
      default:
        miscRegFile[misc_reg] = val;
        break;
    }
}

void
ISA::setMiscReg(int misc_reg, const MiscReg &val, ThreadContext *tc)
{
    if (bits((unsigned)misc_reg, 11, 10) == 0x3) {
        warn("Ignoring write to read-only CSR.");
        return;
    }
    setMiscRegNoEffect(misc_reg, val);
}

}

RiscvISA::ISA *
RiscvISAParams::create()
{
    return new RiscvISA::ISA(this);
}