package xiangshan.backend.fu.NewCSR

import chisel3._
import chisel3.util._
import freechips.rocketchip.rocket.CSRs
import xiangshan.backend.fu.NewCSR.CSRDefines.{CSRROField => RO, CSRRWField => RW, CSRWARLField => WARL}
import xiangshan.backend.fu.NewCSR.CSRFunc._
import xiangshan.backend.fu.vector.Bundles._
import xiangshan.backend.fu.NewCSR.CSRConfig._
import xiangshan.backend.fu.fpu.Bundles.{Fflags, Frm}
import xiangshan.backend.fu.NewCSR.CSREnumTypeImplicitCast._

import scala.collection.immutable.SeqMap

trait Unprivileged { self: NewCSR with MachineLevel with SupervisorLevel =>

  val fcsr = Module(new CSRModule("Fcsr", new CSRBundle {
    val NX = WARL(0, wNoFilter)
    val UF = WARL(1, wNoFilter)
    val OF = WARL(2, wNoFilter)
    val DZ = WARL(3, wNoFilter)
    val NV = WARL(4, wNoFilter)
    val FRM = WARL(7, 5, wNoFilter)
  }) with HasRobCommitBundle {
    val wAliasFflags = IO(Input(new CSRAddrWriteBundle(new CSRFFlagsBundle)))
    val wAliasFfm = IO(Input(new CSRAddrWriteBundle(new CSRFrmBundle)))
    val fflags = IO(Output(Fflags()))
    val frm = IO(Output(Frm()))

    // write connection
    this.wfn(reg)(Seq(wAliasFflags, wAliasFfm))

    when (robCommit.fflags.valid) {
      reg.NX := robCommit.fflags.bits(0) || reg.NX
      reg.UF := robCommit.fflags.bits(1) || reg.UF
      reg.OF := robCommit.fflags.bits(2) || reg.OF
      reg.DZ := robCommit.fflags.bits(3) || reg.DZ
      reg.NV := robCommit.fflags.bits(4) || reg.NV
    }

    // read connection
    fflags := reg.asUInt(4, 0)
    frm := reg.FRM.asUInt
  }).setAddr(0x003)

  // vec
  val vstart = Module(new CSRModule("Vstart", new CSRBundle {
    val vstart = RW(VlWidth - 2, 0) // hold [0, 128)
  }) with HasRobCommitBundle {
    // Todo make The use of vstart values greater than the largest element index for the current SEW setting is reserved.
    // Not trap
    when (wen && this.w.wdata < VLEN.U) {
      reg.vstart := this.w.wdata(VlWidth - 2, 0)
    }.elsewhen (robCommit.vstart.valid) {
      reg.vstart := robCommit.vstart.bits
    }
  })
    .setAddr(0x008)

  val vcsr = Module(new CSRModule("Vcsr", new CSRBundle {
    val VXSAT = RW(   0)
    val VXRM  = RW(2, 1)
  }) with HasRobCommitBundle {
    val wAliasVxsat = IO(Input(new CSRAddrWriteBundle(new CSRBundle {
      val VXSAT = RW(0)
    })))
    val wAlisaVxrm = IO(Input(new CSRAddrWriteBundle(new CSRBundle {
      val VXRM = RW(1, 0)
    })))
    val vxsat = IO(Output(Vxsat()))
    val vxrm  = IO(Output(Vxrm()))

    // write connection
    this.wfn(reg)(Seq(wAliasVxsat, wAlisaVxrm))

    when(robCommit.vxsat.valid) {
      reg.VXSAT := reg.VXSAT.asBool || robCommit.vxsat.bits.asBool
    }

    // read connection
    vxsat := reg.VXSAT.asUInt
    vxrm  := reg.VXRM.asUInt
  }).setAddr(0x00F)

  val vl = Module(new CSRModule("Vl", new CSRBundle {
    val VL = RO(VlWidth - 1, 0)
  }) with HasRobCommitBundle {
    when (robCommit.vl.valid) {
      reg.VL := robCommit.vl.bits
    }
  })
    .setAddr(0xC20)

  val vtype = Module(new CSRModule("Vtype", new CSRVTypeBundle) with HasRobCommitBundle {
    when(robCommit.vtype.valid) {
      reg := robCommit.vtype.bits
    }
  })
    .setAddr(0xC21)

  val vlenb = Module(new CSRModule("Vlenb", new CSRBundle {
    val VLENB = VlenbField(63, 0).withReset(VlenbField.init)
  }))
    .setAddr(0xC22)

  val cycle = Module(new CSRModule("cycle", new CSRBundle {
    val cycle = RO(63, 0)
  }) with HasMHPMSink {
    regOut.cycle := mHPM.cycle
  })
    .setAddr(CSRs.cycle)

  val time = Module(new CSRModule("time", new CSRBundle {
    val time = RO(63, 0)
  }) with HasMHPMSink {
    when (mHPM.time.valid) {
      reg.time := mHPM.time.bits
    }
  })
    .setAddr(CSRs.time)

  val instret = Module(new CSRModule("instret", new CSRBundle {
    val instret = RO(63, 0)
  }) with HasMHPMSink {
    regOut.instret := mHPM.instret
  })
    .setAddr(CSRs.instret)

  val unprivilegedCSRMap: SeqMap[Int, (CSRAddrWriteBundle[_], Data)] = SeqMap(
    0x001 -> (fcsr.wAliasFflags -> fcsr.fflags),
    0x002 -> (fcsr.wAliasFfm    -> fcsr.frm),
    0x003 -> (fcsr.w            -> fcsr.rdata),
    0x008 -> (vstart.w          -> vstart.rdata),
    0x009 -> (vcsr.wAliasVxsat  -> vcsr.vxsat),
    0x00A -> (vcsr.wAlisaVxrm   -> vcsr.vxrm),
    0x00F -> (vcsr.w            -> vcsr.rdata),
    0xC20 -> (vl.w              -> vl.rdata),
    0xC21 -> (vtype.w           -> vtype.rdata),
    0xC22 -> (vlenb.w           -> vlenb.rdata),
    CSRs.cycle -> (cycle.w      -> cycle.rdata),
    CSRs.time -> (time.w        -> time.rdata),
    CSRs.instret -> (instret.w  -> instret.rdata),
  )

  val unprivilegedCSRMods: Seq[CSRModule[_]] = Seq(
    fcsr,
    vcsr,
    vstart,
    vl,
    vtype,
    vlenb,
    cycle,
    time,
    instret,
  )

  val unprivilegedCSROutMap: SeqMap[Int, UInt] = SeqMap(
    0x001 -> fcsr.fflags.asUInt,
    0x002 -> fcsr.frm.asUInt,
    0x003 -> fcsr.rdata.asUInt,
    0x008 -> vcsr.rdata.asUInt,
    0x009 -> vcsr.vxsat.asUInt,
    0x00A -> vcsr.vxrm.asUInt,
    0x00F -> vcsr.rdata.asUInt,
    0xC20 -> vl.rdata.asUInt,
    0xC21 -> vtype.rdata.asUInt,
    0xC22 -> vlenb.rdata.asUInt,
    CSRs.cycle   -> cycle.rdata,
    CSRs.time    -> time.rdata,
    CSRs.instret -> instret.rdata,
  )
}

class CSRVTypeBundle extends CSRBundle {
  val VILL  = RO(  63)
  val VMA   = RO(   7)
  val VTA   = RO(   6)
  val VSEW  = RO(5, 3)
  val VLMUL = RO(2, 0)
}

class CSRFrmBundle extends CSRBundle {
  val FRM = WARL(2, 0, wNoFilter)
}

class CSRFFlagsBundle extends CSRBundle {
  val NX = WARL(0, wNoFilter)
  val UF = WARL(1, wNoFilter)
  val OF = WARL(2, wNoFilter)
  val DZ = WARL(3, wNoFilter)
  val NV = WARL(4, wNoFilter)
}

object VlenbField extends CSREnum with ROApply {
  val init = Value((VLEN / 8).U)
}

trait HasMHPMSink { self: CSRModule[_] =>
  val mHPM = IO(Input(new Bundle {
    val cycle   = UInt(64.W)
    // ValidIO is used to update time reg
    val time    = ValidIO(UInt(64.W))
    val instret = UInt(64.W)
  }))
}