package xiangshan.backend.issue

import chisel3._
import chisel3.util._
import xiangshan._
import utils._
import xiangshan.backend.SelImm
import xiangshan.backend.decode.{ImmUnion, Imm_U}
import xiangshan.backend.exu.{Exu, ExuConfig}
import xiangshan.backend.regfile.RfReadPort
import xiangshan.backend.roq.RoqPtr

import scala.math.max

class BypassQueue(number: Int) extends XSModule {
  val io = IO(new Bundle {
    val in  = Flipped(ValidIO(new MicroOp))
    val out = ValidIO(new MicroOp)
    val redirect = Flipped(ValidIO(new Redirect))
  })
  if (number < 0) {
    io.out.valid := false.B
    io.out.bits := DontCare
  } else if(number == 0) {
    io.in <> io.out
    io.out.valid := io.in.valid
    // NOTE: no delay bypass don't care redirect
  } else {
    val queue = Seq.fill(number)(RegInit(0.U.asTypeOf(new Bundle{
      val valid = Bool()
      val bits = new MicroOp
    })))
    queue(0).valid := io.in.valid && !io.in.bits.roqIdx.needFlush(io.redirect)
    queue(0).bits  := io.in.bits
    (0 until (number-1)).map{i =>
      queue(i+1) := queue(i)
      queue(i+1).valid := queue(i).valid && !queue(i).bits.roqIdx.needFlush(io.redirect)
    }
    io.out.valid := queue(number-1).valid
    io.out.bits := queue(number-1).bits
    for (i <- 0 until number) {
      XSDebug(queue(i).valid, p"BPQue(${i.U}): pc:${Hexadecimal(queue(i).bits.cf.pc)} roqIdx:${queue(i).bits.roqIdx}" +
        p" pdest:${queue(i).bits.pdest} rfWen:${queue(i).bits.ctrl.rfWen} fpWen${queue(i).bits.ctrl.fpWen}\n")
    }
  }
}

// multi-read && single-write
// input is data, output is hot-code(not one-hot)
class SingleSrcCAM[T <: Data](val gen: T, val set: Int, val readWidth: Int, rfZero: Boolean) extends XSModule {
  val io = IO(new Bundle {
    val r = new Bundle {
      val req = Input(Vec(readWidth, gen))
      val resp = Output(Vec(readWidth, Vec(set, Bool())))
    }
    val w = new Bundle {
      val valid = Input(Bool())
      val bits = new Bundle {
        val addr = Input(UInt(log2Up(set).W))
        val data = Input(gen)
      }
    }
    val zero = if (rfZero) Output(Vec(set, Bool())) else null
  })

  val wordType = UInt(gen.getWidth.W)
  val array = Reg(Vec(set, wordType))

  io.r.resp.zipWithIndex.map{ case (a,i) =>
    a := array.map( src => io.r.req(i).asUInt === src)
  }

  // Note: general reg file don't wakeup zero
  if (rfZero) { io.zero.zip(array).map{ case(z, a) => z := a===0.U }}

  when (io.w.valid) {
    array(io.w.bits.addr) := io.w.bits.data
  }
}

class ReservationStation
(
  val exuCfg: ExuConfig,
  fastPortsCnt: Int,
  slowPortsCnt: Int,
  fixedDelay: Int,
  fastWakeup: Boolean,
  feedback: Boolean,
) extends XSModule {
  val iqSize = IssQueSize
  val iqIdxWidth = log2Up(iqSize)
  val nonBlocked = fixedDelay >= 0
  val srcNum = max(exuCfg.intSrcCnt, exuCfg.fpSrcCnt)
  require(nonBlocked==fastWakeup)

  val io = IO(new Bundle {
    val numExist = Output(UInt(iqIdxWidth.W))
    val fromDispatch = Flipped(DecoupledIO(new MicroOp))
    val deq = DecoupledIO(new ExuInput)
    val srcRegValue = Input(Vec(srcNum, UInt((XLEN + 1).W)))
    val jumpPc = if(exuCfg == Exu.jumpExeUnitCfg) Input(UInt(VAddrBits.W)) else null

    val fastUopOut = ValidIO(new MicroOp)
    val fastUopsIn = Vec(fastPortsCnt, Flipped(ValidIO(new MicroOp)))
    val fastDatas = Vec(fastPortsCnt, Input(UInt((XLEN+1).W)))
    val slowPorts = Vec(slowPortsCnt, Flipped(ValidIO(new ExuOutput)))

    val redirect = Flipped(ValidIO(new Redirect))
    val feedback = Flipped(ValidIO(new RSFeedback))
  })

  val select = Module(new ReservationStationSelect(exuCfg, fastPortsCnt, slowPortsCnt, fixedDelay, fastWakeup, feedback))
  val ctrl   = Module(new ReservationStationCtrl(exuCfg, fastPortsCnt, slowPortsCnt, fixedDelay, fastWakeup, feedback))
  val data   = Module(new ReservationStationData(exuCfg, fastPortsCnt, slowPortsCnt, fixedDelay, fastWakeup, feedback))

  select.io.redirect := ctrl.io.redirect
  io.numExist := select.io.numExist
  select.io.feedbackVec := ctrl.io.feedbackVec
  select.io.redirectVec := ctrl.io.redirectVec
  select.io.readyVec := ctrl.io.readyVec
  select.io.enq.valid := io.fromDispatch.valid
  io.fromDispatch.ready := select.io.enq.ready
  select.io.deq.ready := io.deq.ready

  ctrl.io.in.valid := select.io.enq.fire() && !io.redirect.valid // NOTE: same as select
  ctrl.io.in.bits.addr := select.io.enq.bits
  ctrl.io.in.bits.uop := io.fromDispatch.bits
  ctrl.io.redirect := io.redirect
  ctrl.io.feedback := io.feedback
  ctrl.io.sel.valid := select.io.deq.valid
  ctrl.io.sel.bits  := select.io.deq.bits
  io.fastUopOut := ctrl.io.fastUopOut
  ctrl.io.fastUopsIn := io.fastUopsIn
  ctrl.io.slowUops.zip(io.slowPorts).map{ case (c, i) =>
    c.valid := i.valid
    c.bits  := i.bits.uop
  }

  data.io.in.valid := ctrl.io.in.valid
  data.io.in.addr := ctrl.io.in.bits.addr
  data.io.in.uop := ctrl.io.in.bits.uop // NOTE: use for imm-pc src value mux
  data.io.in.enqSrcReady := ctrl.io.enqSrcReady
  data.io.srcRegValue := io.srcRegValue
  if(exuCfg == Exu.jumpExeUnitCfg) {
    data.io.jumpPc := io.jumpPc
  }
  data.io.sel := select.io.deq.bits
  data.io.listen.wen := ctrl.io.listen
  for (i <- 0 until fastPortsCnt) {
    data.io.listen.wdata(i) := io.fastDatas(i)
  }
  for (i <- 0 until slowPortsCnt) {
    data.io.listen.wdata(i + fastPortsCnt) := io.slowPorts(i).bits.data
  }

  io.deq.bits := DontCare
  io.deq.bits.uop  := ctrl.io.out.bits
  io.deq.bits.uop.cf.exceptionVec := 0.U.asTypeOf(ExceptionVec())
  io.deq.valid     := ctrl.io.out.valid
  io.deq.bits.src1 := data.io.out(0)
  if (srcNum > 1) { io.deq.bits.src2 := data.io.out(1) }
  if (srcNum > 2) { io.deq.bits.src3 := data.io.out(2) }
}

class ReservationStationSelect
(
  val exuCfg: ExuConfig,
  fastPortsCnt: Int,
  slowPortsCnt: Int,
  fixedDelay: Int,
  fastWakeup: Boolean,
  feedback: Boolean,
) extends XSModule with HasCircularQueuePtrHelper{

  val iqSize = IssQueSize
  val iqIdxWidth = log2Up(iqSize)
  val nonBlocked = fixedDelay >= 0
  val srcNum = max(exuCfg.intSrcCnt, exuCfg.fpSrcCnt)
  require(nonBlocked==fastWakeup)
  val replayDelay = 5

  val io = IO(new Bundle {
    val redirect = Flipped(ValidIO(new Redirect))
    val numExist = Output(UInt(iqIdxWidth.W))

    val feedbackVec = Input(Vec(IssQueSize+1, Bool()))
    val redirectVec = Input(Vec(IssQueSize, Bool()))
    val readyVec = Input(Vec(IssQueSize, Bool()))

    // val enq = Flipped(DecoupledIO(UInt(iqIdxWidth.W)))
    val enq = new Bundle {
      val valid = Input(Bool())
      val bits  = Output(UInt(iqIdxWidth.W))
      val ready = Output(Bool())
      def fire() = valid && ready
    }
    val deq = DecoupledIO(UInt(iqIdxWidth.W))
  })

  def widthMap[T <: Data](f: Int => T) = VecInit((0 until iqSize).map(f))

  /* queue in ctrl part
   * index queue : index
   * state queue : use for replay
   * count   queue : record replay cycle
   */

  val s_idle :: s_valid :: s_wait :: s_replay :: Nil = Enum(4)
  /* state machine
   * s_idle     : empty slot, init state, set when deq
   * s_valid    : ready to be secleted
   * s_wait     : wait for feedback
   * s_replay   : replay after some particular cycle
   */
  val stateQueue    = RegInit(VecInit(Seq.fill(iqSize)(s_idle)))
  val tailPtr       = RegInit(0.U.asTypeOf(new CircularQueuePtr(iqSize)))
  val indexQueue    = RegInit(VecInit((0 until iqSize).map(_.U(iqIdxWidth.W))))
  val validQueue    = VecInit(stateQueue.map(_ === s_valid))
  val emptyQueue    = VecInit(stateQueue.map(_ === s_idle))
  val countQueue    = Reg(Vec(iqSize, UInt(log2Up(replayDelay).W)))
  val validIdxQueue = widthMap(i => validQueue(indexQueue(i)))
  val readyIdxQueue = widthMap(i => validQueue(indexQueue(i)) && io.readyVec(indexQueue(i)))
  val emptyIdxQueue = widthMap(i => emptyQueue(indexQueue(i)))
  val countIdxQueue = widthMap(i => countQueue(indexQueue(i)))

  // select ready
  // for no replay, select just equal to deq (attached)
  // with   replay, select is just two stage with deq.
  val issueFire = Wire(Bool())
  val moveMask = WireInit(0.U(iqSize.W))
  val lastSelMask = Wire(UInt(iqSize.W))
  val selectMask = WireInit(VecInit((0 until iqSize).map(i => readyIdxQueue(i)))).asUInt & lastSelMask
  val selectIndex = ParallelPriorityMux(selectMask.asBools zip indexQueue) // NOTE: the idx in the indexQueue
  val selectPtr = ParallelPriorityMux(selectMask.asBools.zipWithIndex.map{ case (a,i) => (a, i.U)}) // NOTE: the idx of indexQueue
  val haveReady = Cat(selectMask).orR
  val selectIndexReg = RegNext(selectIndex)
  val selectValid = haveReady
  val selectReg = RegNext(selectValid)
  val selectPtrReg = RegNext(Mux(moveMask(selectPtr), selectPtr-1.U, selectPtr))
  lastSelMask := ~Mux(selectReg, UIntToOH(selectPtrReg), 0.U)
  assert(RegNext(!(haveReady && selectPtr >= tailPtr.asUInt)), "bubble should not have valid state like s_valid or s_wait")

  // sel bubble
  val lastbubbleMask = Wire(UInt(iqSize.W))
  val bubbleMask = WireInit(VecInit((0 until iqSize).map(i => emptyIdxQueue(i)))).asUInt & lastbubbleMask
  // val bubbleIndex = ParallelMux(bubbleMask zip indexQueue) // NOTE: the idx in the indexQueue
  val bubblePtr= ParallelPriorityMux(bubbleMask.asBools.zipWithIndex.map{ case (a,i) => (a, i.U)}) // NOTE: the idx of the indexQueue
  val findBubble = Cat(bubbleMask).orR
  val haveBubble = findBubble && (bubblePtr < tailPtr.asUInt)
  val bubbleIndex = indexQueue(bubblePtr)
  val bubbleValid = haveBubble && (if (feedback) true.B else !selectValid)
  val bubbleReg = RegNext(bubbleValid)
  val bubblePtrReg = RegNext(Mux(moveMask(bubblePtr), bubblePtr-1.U, bubblePtr))
  lastbubbleMask := ~Mux(bubbleReg, UIntToOH(bubblePtrReg), 0.U) &
                    (if(feedback) ~(0.U(iqSize.W)) else
                    Mux(RegNext(selectValid && io.redirect.valid), 0.U, ~(0.U(iqSize.W))))

  // deq
  val dequeue = if (feedback) bubbleReg
                else          bubbleReg || issueFire
  val deqPtr =  if (feedback) bubblePtrReg
                else Mux(selectReg, selectPtrReg, bubblePtrReg)
  moveMask := {
    (Fill(iqSize, 1.U(1.W)) << deqPtr)(iqSize-1, 0)
  } & Fill(iqSize, dequeue)

  for (i <- 0 until iqSize - 1) {
    when(moveMask(i)){
      indexQueue(i) := indexQueue(i+1)
    }
  }
  when(dequeue){
    indexQueue.last := indexQueue(deqPtr)
  }

  when (issueFire) {
    if (feedback) { when (stateQueue(selectIndexReg) === s_valid) { stateQueue(selectIndexReg) := s_wait } }
    else { stateQueue(selectIndexReg) := s_idle } // NOTE: reset the state for seclectMask timing to avoid operaion '<'
  }

  // redirect and feedback && wakeup
  for (i <- 0 until iqSize) {
    // replay
    val count = countQueue(i)
    when (stateQueue(i) === s_replay) {
      count := count - 1.U
      when (count === 0.U) { stateQueue(i) := s_valid }
    }
    if (feedback) {
      val feedbackMatchVec = widthMap(i => io.feedbackVec(i) && (stateQueue(i) === s_wait || stateQueue(i)===s_valid)).asUInt
      val feedbackHit       = io.feedbackVec(iqSize)
      // feedback
      when (feedbackMatchVec(i)) {
        stateQueue(i) := Mux(!feedbackHit, s_replay, s_idle)
        countQueue(i) := Mux(feedbackHit, count, (replayDelay-1).U)
      }
    }

    // redirect
    when (io.redirectVec(i) && stateQueue(i) =/= s_idle) {
      stateQueue(i) := s_idle
    }
  }

  // output
  val issueValid = selectReg
  if (nonBlocked) {
    issueFire := issueValid
  } else {
    issueFire := issueValid && io.deq.ready
  }

  // enq
  val isFull = tailPtr.flag
  // agreement with dispatch: don't fire when io.redirect.valid
  val enqueue = io.enq.fire() && !io.redirect.valid
  val tailInc = tailPtr + 1.U
  val tailDec = tailPtr - 1.U
  tailPtr := Mux(dequeue === enqueue, tailPtr, Mux(dequeue, tailDec, tailInc))

  val enqPtr = Mux(tailPtr.flag, deqPtr, tailPtr.value)
  val enqIdx = indexQueue(enqPtr)
  when (enqueue) {
    stateQueue(enqIdx) := s_valid
  }

  io.enq.ready := !isFull || (if(feedback || nonBlocked) dequeue else false.B)
  io.enq.bits  := enqIdx
  io.deq.valid := selectValid
  io.deq.bits  := selectIndex

  io.numExist := Mux(tailPtr.flag, (iqSize-1).U, tailPtr.value)

  assert(RegNext(Mux(tailPtr.flag, tailPtr.value===0.U, true.B)))
}

class ReservationStationCtrl
(
  val exuCfg: ExuConfig,
  fastPortsCnt: Int,
  slowPortsCnt: Int,
  fixedDelay: Int,
  fastWakeup: Boolean,
  feedback: Boolean,
) extends XSModule {

  val iqSize = IssQueSize
  val iqIdxWidth = log2Up(iqSize)
  val nonBlocked = fixedDelay >= 0
  val srcNum = max(exuCfg.intSrcCnt, exuCfg.fpSrcCnt)
  require(nonBlocked==fastWakeup)

  val io = IO(new XSBundle {

    val redirect = Flipped(ValidIO(new Redirect))

    val in = Flipped(ValidIO(new Bundle {
      val addr = UInt(iqIdxWidth.W)
      val uop  = new MicroOp
    }))
    val sel = Flipped(ValidIO(UInt(iqIdxWidth.W)))
    val out = ValidIO(new MicroOp)

    val feedbackVec = Output(Vec(IssQueSize+1, Bool()))
    val redirectVec = Output(Vec(IssQueSize, Bool()))
    val readyVec = Output(Vec(IssQueSize, Bool()))

    val fastUopOut = ValidIO(new MicroOp)
    val fastUopsIn = Flipped(Vec(fastPortsCnt, ValidIO(new MicroOp)))
    val slowUops   = Flipped(Vec(slowPortsCnt, ValidIO(new MicroOp)))

    val listen = Output(Vec(srcNum, Vec(iqSize, Vec(fastPortsCnt + slowPortsCnt, Bool()))))
    val enqSrcReady = Output(Vec(srcNum, Bool()))

    val feedback = Flipped(ValidIO(new RSFeedback))
  })

  val enqPtr = io.in.bits.addr
  val enqPtrReg = RegNext(enqPtr)
  val enqEn  = io.in.valid
  val enqEnReg = RegNext(enqEn)
  val enqUop = io.in.bits.uop
  val enqUopReg = RegEnable(enqUop, io.sel.valid)
  val selPtr = io.sel.bits
  val deqPtr = RegEnable(selPtr, io.sel.valid)
  val data = io.listen
  data.map(a => a.map(b => b.map(_ := false.B)))

  val fastUops = io.fastUopsIn
  val slowUops = io.slowUops
  val lastFastUops = RegNext(fastUops)

  def stateCheck(src: UInt, srcType: UInt): Bool = {
    (srcType =/= SrcType.reg && srcType =/= SrcType.fp) ||
    (srcType === SrcType.reg && src === 0.U)
  }
  val enqSrcSeq      = Seq(enqUop.psrc1, enqUop.psrc2, enqUop.psrc3)
  val enqSrcTypeSeq  = Seq(enqUop.ctrl.src1Type, enqUop.ctrl.src2Type, enqUop.ctrl.src3Type)
  val enqSrcStateSeq = Seq(enqUop.src1State, enqUop.src2State, enqUop.src3State)
  val enqSrcReady = (0 until srcNum).map(i =>
    stateCheck(enqSrcSeq(i), enqSrcTypeSeq(i)) || (enqSrcStateSeq(i) === SrcState.rdy)
  )
  io.enqSrcReady := enqSrcReady
  val srcUpdate = Wire(Vec(iqSize, Vec(srcNum, Bool())))
  srcUpdate.map(a => a.map(b => b := false.B))

  val srcQueue      = Reg(Vec(iqSize, Vec(srcNum, Bool())))
  io.readyVec := srcQueue.map(Cat(_).andR)
  when (enqEn) {
    srcQueue(enqPtr).zip(enqSrcReady).map{ case (s, e) => s := e }
  }
  for (i <- 0 until iqSize) {
    for (j <- 0 until srcNum) {
      when (srcUpdate(i)(j)) { srcQueue(i)(j) := true.B }
    }
  }

  val redirectHit = io.redirectVec(selPtr)
  val uop = if (fastWakeup) {
    Module(new AsyncDataModuleTemplate(new MicroOp, iqSize, 2, 1))
  } else {
    Module(new SyncDataModuleTemplate(new MicroOp, iqSize, 1, 1))
  }

  uop.io.raddr(0) := RegNext(io.sel.bits)
  io.out.valid    := RegNext(io.sel.valid && ~redirectHit)
  io.out.bits     := uop.io.rdata(0)
  uop.io.wen(0)   := io.in.valid
  uop.io.waddr(0) := io.in.bits.addr
  uop.io.wdata(0) := io.in.bits.uop

  val roqIdx = Reg(Vec(IssQueSize, new RoqPtr))
  when (enqEn) {
    roqIdx(enqPtr) := enqUop.roqIdx
  }
  io.redirectVec.zip(roqIdx).map{ case (red, roq) =>
    red := roq.needFlush(io.redirect)
  }

  io.feedbackVec := DontCare
  if (feedback) {
    (0 until iqSize).foreach{ i =>
      io.feedbackVec(i) := roqIdx(i).asUInt === io.feedback.bits.roqIdx.asUInt && io.feedback.valid
    }
    io.feedbackVec(iqSize) := io.feedback.bits.hit
  }

  io.fastUopOut := DontCare
  if (fastWakeup) {
    uop.io.raddr(1) := io.sel.bits
    if (fixedDelay == 0) {
      io.fastUopOut.valid := io.sel.valid
      io.fastUopOut.bits  := uop.io.rdata(1)
      io.fastUopOut.bits.cf.exceptionVec  := 0.U.asTypeOf(ExceptionVec())
    } else {
      val bpQueue = Module(new BypassQueue(fixedDelay))
      bpQueue.io.in.valid := io.sel.valid // FIXME: error when function is blocked => fu should not be blocked
      bpQueue.io.in.bits  := uop.io.rdata(1)
      bpQueue.io.redirect := io.redirect
      io.fastUopOut.valid := bpQueue.io.out.valid
      io.fastUopOut.bits  := bpQueue.io.out.bits
      io.fastUopOut.bits.cf.exceptionVec  := 0.U.asTypeOf(ExceptionVec())
    }
  }

  val psrc = (0 until srcNum).map(i => Module(new SingleSrcCAM(UInt(PhyRegIdxWidth.W), iqSize, fastPortsCnt + slowPortsCnt, true)).io)
  psrc.map(_.w.valid := false.B)
  val entryListenHit = psrc.map{src =>
    for (i <- 0 until fastPortsCnt) { src.r.req(i) := io.fastUopsIn(i).bits.pdest }
    for (i <- 0 until slowPortsCnt) { src.r.req(i + fastPortsCnt) := io.slowUops(i).bits.pdest }
    src.r.resp
  }
  val srcIsZero = psrc.map{ src => src.zero }
  psrc.map(_.w.bits.addr  := enqPtr)
  psrc.map(_.w.valid := enqEn)
  val enqSrcSeqChecked = enqSrcSeq.zip(enqSrcTypeSeq).map{ case (s, t) =>
    Mux(t === SrcType.fp || t === SrcType.reg, s, 0.U)} // NOTE: if pc/imm -> 0.U and reg (means don't hit)
  psrc.zip(enqSrcSeq).map{ case (p,s) => p.w.bits.data := s }

  // TODO: later, only store will need psrcType
  val psrcType = Reg(Vec(srcNum, Vec(iqSize, Bool()))) // fp: true | other: false
  (0 until srcNum).foreach{ i =>
    when (enqEn) {
      psrcType(i)(enqPtr) := enqSrcTypeSeq(i) =/= SrcType.fp
    }
  }

  def listenHitEnq(uop: MicroOp, src: UInt, srctype: UInt): Bool = {
    (src === uop.pdest) &&
    ((srctype === SrcType.reg && uop.ctrl.rfWen && src=/=0.U) ||
     (srctype === SrcType.fp  && uop.ctrl.fpWen))
  }

  def listenHitEntry(src: Int, port: Int, addr: Int, uop: MicroOp): Bool = {
    entryListenHit(src)(port)(addr) &&
    ((!psrcType(src)(addr) && uop.ctrl.rfWen && !srcIsZero(src)(addr)) ||
     (psrcType(src)(addr)  && uop.ctrl.fpWen))
  }

  for (j <- 0 until srcNum) {
    for (i <- 0 until iqSize) {
      for (k <- 0 until fastPortsCnt) {
        val fastHit = listenHitEntry(j, k, i, fastUops(k).bits) && fastUops(k).valid
        val fastHitNoConflict = fastHit && !(enqPtr===i.U && enqEn)
        when (fastHitNoConflict) { srcUpdate(i)(j) := true.B }
        when (RegNext(fastHitNoConflict) && !(enqPtr===i.U && enqEn)) { data(j)(i)(k) := true.B }
      }
      for (k <- 0 until slowPortsCnt) {
        val slowHit = listenHitEntry(j, k + fastPortsCnt, i, slowUops(k).bits) && slowUops(k).valid
        val slowHitNoConflict = slowHit && !(enqPtr===i.U && enqEn)
        when (slowHitNoConflict) { srcUpdate(i)(j) := true.B }
        when (slowHitNoConflict) { data(j)(i)(k + fastPortsCnt) := true.B }
      }
    }
  }

  // enq listen
  for (j <- 0 until srcNum) {
    for (k <- 0 until fastPortsCnt) {
      val fastHit = listenHitEnq(fastUops(k).bits, enqSrcSeq(j), enqSrcTypeSeq(j)) && enqEn && fastUops(k).valid
      val lastFastHit = listenHitEnq(lastFastUops(k).bits, enqSrcSeq(j), enqSrcTypeSeq(j)) && enqEn && lastFastUops(k).valid
      when (fastHit || lastFastHit) { srcUpdate(enqPtr)(j) := true.B }
      when (lastFastHit)            { data(j)(enqPtr)(k) := true.B }
      when (RegNext(fastHit))       { data(j)(enqPtrReg)(k) := true.B }
    }
    for (k <- 0 until slowPortsCnt) {
      val slowHit = listenHitEnq(slowUops(k).bits, enqSrcSeq(j), enqSrcTypeSeq(j)) && enqEn && slowUops(k).valid
      when (slowHit) {
        srcUpdate(enqPtr)(j) := true.B
        data(j)(enqPtr)(k + fastPortsCnt) := true.B
      }
    }
  }
}

class RSDataSingleSrc(srcLen: Int, numEntries: Int, numListen: Int) extends XSModule {
  val io = IO(new Bundle {
    val r = new Bundle {
      // val valid = Bool() // NOTE: if read valid is necessary, but now it is not completed
      val addr = Input(UInt(log2Up(numEntries).W))
      val rdata = Output(UInt(srcLen.W))
    }
    val w = Input(new Bundle {
      val wen = Bool()
      val addr = UInt(log2Up(numEntries).W)
      val wdata = Input(UInt(srcLen.W))
    })
    val listen = Input(new Bundle {
      val wdata = Vec(numListen, UInt(srcLen.W))
      val wen = Vec(numEntries, Vec(numListen, Bool()))
    })
  })

  val value = Reg(Vec(numEntries, UInt(srcLen.W)))

  val wMask = Mux(io.w.wen, UIntToOH(io.w.addr)(numEntries-1, 0), 0.U(numEntries.W))
  val data = io.listen.wdata :+ io.w.wdata
  val wen = io.listen.wen.zip(wMask.asBools).map{ case (w, m) => w :+ m }
  for (i <- 0 until numEntries) {
    when (Cat(wen(i)).orR) {
      value(i) := ParallelMux(wen(i) zip data)
      assert(RegNext(PopCount(wen(i))===0.U || PopCount(wen(i))===1.U), s"${i}")
    }
  }

  io.r.rdata := value(RegNext(io.r.addr)) // NOTE: the read addr will arrive one cycle before
}

class ReservationStationData
(
  val exuCfg: ExuConfig,
  fastPortsCnt: Int,
  slowPortsCnt: Int,
  fixedDelay: Int,
  fastWakeup: Boolean,
  feedback: Boolean,
) extends XSModule {
  val iqSize = IssQueSize
  val iqIdxWidth = log2Up(iqSize)
  val nonBlocked = fixedDelay >= 0
  val srcNum = max(exuCfg.intSrcCnt, exuCfg.fpSrcCnt)
  require(nonBlocked==fastWakeup)

  val io = IO(new XSBundle {
    val srcRegValue = Vec(srcNum, Input(UInt((XLEN + 1).W)))
    val jumpPc = if(exuCfg == Exu.jumpExeUnitCfg) Input(UInt(VAddrBits.W)) else null
    val in  = Input(new Bundle {
      val valid = Input(Bool())
      val addr = Input(UInt(iqIdxWidth.W))
      val uop = Input(new MicroOp)
      val enqSrcReady = Input(Vec(srcNum, Bool()))
    })

    val listen = new Bundle {
      val wen = Input(Vec(srcNum, Vec(iqSize, Vec(fastPortsCnt + slowPortsCnt, Bool()))))
      val wdata = Input(Vec(fastPortsCnt + slowPortsCnt, UInt((XLEN + 1).W)))
    }

    val sel = Input(UInt(iqIdxWidth.W))
    val out = Output(Vec(srcNum, UInt((XLEN + 1).W)))
  })

  val enqUopReg = RegEnable(io.in.uop, io.in.valid)

  // Data : single read, multi write
  // ------------------------
  val data = (0 until srcNum).map{i =>
    val d = Module(new RSDataSingleSrc(XLEN + 1, iqSize, fastPortsCnt + slowPortsCnt))
    d.suggestName(s"${this.name}_data${i}")
    d.io
  }
  (0 until srcNum).foreach{ i =>
    data(i).listen.wen := io.listen.wen(i)
    data(i).listen.wdata := io.listen.wdata
  }

  data.map(_.w.addr  := RegEnable(io.in.addr, io.in.valid))
  data.zip(io.in.enqSrcReady).map{ case (src, ready) => src.w.wen := RegNext(ready && io.in.valid) }

  exuCfg match {
    case Exu.jumpExeUnitCfg =>
      val src1Mux = Mux(enqUopReg.ctrl.src1Type === SrcType.pc,
                        SignExt(io.jumpPc, XLEN),
                        io.srcRegValue(0)
                    )
      // data.io.w.bits.data(0) := src1Mux
      data(0).w.wdata := src1Mux

    case Exu.aluExeUnitCfg =>
      val src1Mux = Mux(enqUopReg.ctrl.src1Type === SrcType.pc,
                      SignExt(enqUopReg.cf.pc, XLEN),
                      io.srcRegValue(0)
                    )
      data(0).w.wdata := src1Mux
      // alu only need U type and I type imm
      val imm32 = Mux(enqUopReg.ctrl.selImm === SelImm.IMM_U,
                    ImmUnion.U.toImm32(enqUopReg.ctrl.imm),
                    ImmUnion.I.toImm32(enqUopReg.ctrl.imm)
                  )
      val imm64 = SignExt(imm32, XLEN)
      val src2Mux = Mux(enqUopReg.ctrl.src2Type === SrcType.imm,
                      imm64, io.srcRegValue(1)
                    )
      data(1).w.wdata := src2Mux
    case _ =>
      (0 until srcNum).foreach(i => data(i).w.wdata := io.srcRegValue(i) )
  }
  // deq
  data.map(_.r.addr := io.sel)
  io.out := data.map(_.r.rdata)
}