xiangshan/frontend/BPU.scala

/***************************************************************************************
* Copyright (c) 2020-2021 Institute of Computing Technology, Chinese Academy of Sciences
* Copyright (c) 2020-2021 Peng Cheng Laboratory
*
* XiangShan is licensed under Mulan PSL v2.
* You can use this software according to the terms and conditions of the Mulan PSL v2.
* You may obtain a copy of Mulan PSL v2 at:
*          http://license.coscl.org.cn/MulanPSL2
*
* THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
* EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
* MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
*
* See the Mulan PSL v2 for more details.
***************************************************************************************/

package xiangshan.frontend

import org.chipsalliance.cde.config.Parameters
import chisel3._
import chisel3.util._
import xiangshan._
import utils._
import utility._

import scala.math.min
import xiangshan.backend.decode.ImmUnion

trait HasBPUConst extends HasXSParameter {
  val MaxMetaBaseLength =  if (!env.FPGAPlatform) 512 else 256 // TODO: Reduce meta length
  val MaxMetaLength = if (HasHExtension) MaxMetaBaseLength + 4 else MaxMetaBaseLength
  val MaxBasicBlockSize = 32
  val LHistoryLength = 32
  // val numBr = 2
  val useBPD = true
  val useLHist = true
  val numBrSlot = numBr-1
  val totalSlot = numBrSlot + 1

  val numDup = 4

  // Used to gate PC higher parts
  val pcSegments = Seq(VAddrBits - 24, 12, 12)

  def BP_STAGES = (0 until 3).map(_.U(2.W))
  def BP_S1 = BP_STAGES(0)
  def BP_S2 = BP_STAGES(1)
  def BP_S3 = BP_STAGES(2)

  def dup_seq[T](src: T, num: Int = numDup) = Seq.tabulate(num)(n => src)
  def dup[T <: Data](src: T, num: Int = numDup) = VecInit(Seq.tabulate(num)(n => src))
  def dup_wire[T <: Data](src: T, num: Int = numDup) = Wire(Vec(num, src.cloneType))
  def dup_idx = Seq.tabulate(numDup)(n => n.toString())
  val numBpStages = BP_STAGES.length

  val debug = true
  // TODO: Replace log2Up by log2Ceil
}

trait HasBPUParameter extends HasXSParameter with HasBPUConst {
  val BPUDebug = true && !env.FPGAPlatform && env.EnablePerfDebug
  val EnableCFICommitLog = true
  val EnbaleCFIPredLog = true
  val EnableBPUTimeRecord = (EnableCFICommitLog || EnbaleCFIPredLog) && !env.FPGAPlatform
  val EnableCommit = false
}

class BPUCtrl(implicit p: Parameters) extends XSBundle {
  val ubtb_enable = Bool()
  val btb_enable  = Bool()
  val bim_enable  = Bool()
  val tage_enable = Bool()
  val sc_enable   = Bool()
  val ras_enable  = Bool()
  val loop_enable = Bool()
}

trait BPUUtils extends HasXSParameter {
  // circular shifting
  def circularShiftLeft(source: UInt, len: Int, shamt: UInt): UInt = {
    val res = Wire(UInt(len.W))
    val higher = source << shamt
    val lower = source >> (len.U - shamt)
    res := higher | lower
    res
  }

  def circularShiftRight(source: UInt, len: Int, shamt: UInt): UInt = {
    val res = Wire(UInt(len.W))
    val higher = source << (len.U - shamt)
    val lower = source >> shamt
    res := higher | lower
    res
  }

  // To be verified
  def satUpdate(old: UInt, len: Int, taken: Bool): UInt = {
    val oldSatTaken = old === ((1 << len)-1).U
    val oldSatNotTaken = old === 0.U
    Mux(oldSatTaken && taken, ((1 << len)-1).U,
      Mux(oldSatNotTaken && !taken, 0.U,
        Mux(taken, old + 1.U, old - 1.U)))
  }

  def signedSatUpdate(old: SInt, len: Int, taken: Bool): SInt = {
    val oldSatTaken = old === ((1 << (len-1))-1).S
    val oldSatNotTaken = old === (-(1 << (len-1))).S
    Mux(oldSatTaken && taken, ((1 << (len-1))-1).S,
      Mux(oldSatNotTaken && !taken, (-(1 << (len-1))).S,
        Mux(taken, old + 1.S, old - 1.S)))
  }

  def getFallThroughAddr(start: UInt, carry: Bool, pft: UInt) = {
    val higher = start.head(VAddrBits-log2Ceil(PredictWidth)-instOffsetBits)
    Cat(Mux(carry, higher+1.U, higher), pft, 0.U(instOffsetBits.W))
  }

  def foldTag(tag: UInt, l: Int): UInt = {
    val nChunks = (tag.getWidth + l - 1) / l
    val chunks = (0 until nChunks).map { i =>
      tag(min((i+1)*l, tag.getWidth)-1, i*l)
    }
    ParallelXOR(chunks)
  }
}

class BasePredictorInput (implicit p: Parameters) extends XSBundle with HasBPUConst {
  def nInputs = 1

  val s0_pc = Vec(numDup, UInt(VAddrBits.W))

  val folded_hist = Vec(numDup, new AllFoldedHistories(foldedGHistInfos))
  val s1_folded_hist = Vec(numDup, new AllFoldedHistories(foldedGHistInfos))
  val ghist = UInt(HistoryLength.W)

  val resp_in = Vec(nInputs, new BranchPredictionResp)

  // val final_preds = Vec(numBpStages, new)
  // val toFtq_fire = Bool()

  // val s0_all_ready = Bool()
}

class BasePredictorOutput (implicit p: Parameters) extends BranchPredictionResp {}

class BasePredictorIO (implicit p: Parameters) extends XSBundle with HasBPUConst {
  val reset_vector = Input(UInt(PAddrBits.W))
  val in  = Flipped(DecoupledIO(new BasePredictorInput)) // TODO: Remove DecoupledIO
  // val out = DecoupledIO(new BasePredictorOutput)
  val out = Output(new BasePredictorOutput)
  // val flush_out = Valid(UInt(VAddrBits.W))

  val fauftb_entry_in = Input(new FTBEntry)
  val fauftb_entry_hit_in = Input(Bool())
  val fauftb_entry_out = Output(new FTBEntry)
  val fauftb_entry_hit_out = Output(Bool())

  val ctrl = Input(new BPUCtrl)

  val s0_fire = Input(Vec(numDup, Bool()))
  val s1_fire = Input(Vec(numDup, Bool()))
  val s2_fire = Input(Vec(numDup, Bool()))
  val s3_fire = Input(Vec(numDup, Bool()))

  val s2_redirect = Input(Vec(numDup, Bool()))
  val s3_redirect = Input(Vec(numDup, Bool()))

  val s1_ready = Output(Bool())
  val s2_ready = Output(Bool())
  val s3_ready = Output(Bool())

  val update = Flipped(Valid(new BranchPredictionUpdate))
  val redirect = Flipped(Valid(new BranchPredictionRedirect))
  val redirectFromIFU = Input(Bool())
}

abstract class BasePredictor(implicit p: Parameters) extends XSModule
  with HasBPUConst with BPUUtils with HasPerfEvents {
  val meta_size = 0
  val spec_meta_size = 0
  val is_fast_pred = false
  val io = IO(new BasePredictorIO())

  io.out := io.in.bits.resp_in(0)

  io.fauftb_entry_out := io.fauftb_entry_in
  io.fauftb_entry_hit_out := io.fauftb_entry_hit_in

  io.out.last_stage_meta := 0.U

  io.in.ready := !io.redirect.valid

  io.s1_ready := true.B
  io.s2_ready := true.B
  io.s3_ready := true.B

  val (_, reset_vector) = DelayNWithValid(io.reset_vector, reset.asBool, 5, hasInit = false)

  val s0_pc_dup   = WireInit(io.in.bits.s0_pc) // fetchIdx(io.f0_pc)
  val s1_pc_dup   = s0_pc_dup.zip(io.s0_fire).map {case (s0_pc, s0_fire) => RegEnable(s0_pc, s0_fire)}
  val s2_pc_dup   = s1_pc_dup.zip(io.s1_fire).map {case (s1_pc, s1_fire) => SegmentedAddrNext(s1_pc, pcSegments, s1_fire, Some("s2_pc"))}
  val s3_pc_dup   = s2_pc_dup.zip(io.s2_fire).map {case (s2_pc, s2_fire) => SegmentedAddrNext(s2_pc, s2_fire, Some("s3_pc"))}

  when (RegNext(RegNext(reset.asBool) && !reset.asBool)) {
    s1_pc_dup.map{case s1_pc => s1_pc := reset_vector}
  }

  io.out.s1.pc := s1_pc_dup
  io.out.s2.pc := s2_pc_dup.map(_.getAddr())
  io.out.s3.pc := s3_pc_dup.map(_.getAddr())

  val perfEvents: Seq[(String, UInt)] = Seq()


  def getFoldedHistoryInfo: Option[Set[FoldedHistoryInfo]] = None
}

class FakePredictor(implicit p: Parameters) extends BasePredictor {
  io.in.ready                 := true.B
  io.out.last_stage_meta      := 0.U
  io.out := io.in.bits.resp_in(0)
}

class BpuToFtqIO(implicit p: Parameters) extends XSBundle {
  val resp = DecoupledIO(new BpuToFtqBundle())
}

class PredictorIO(implicit p: Parameters) extends XSBundle {
  val bpu_to_ftq = new BpuToFtqIO()
  val ftq_to_bpu = Flipped(new FtqToBpuIO)
  val ctrl = Input(new BPUCtrl)
  val reset_vector = Input(UInt(PAddrBits.W))
}

class Predictor(implicit p: Parameters) extends XSModule with HasBPUConst with HasPerfEvents with HasCircularQueuePtrHelper {
  val io = IO(new PredictorIO)

  val ctrl = DelayN(io.ctrl, 1)
  val predictors = Module(if (useBPD) new Composer else new FakePredictor)

  def numOfStage = 3
  require(numOfStage > 1, "BPU numOfStage must be greater than 1")
  val topdown_stages = RegInit(VecInit(Seq.fill(numOfStage)(0.U.asTypeOf(new FrontendTopDownBundle))))

  // following can only happen on s1
  val controlRedirectBubble = Wire(Bool())
  val ControlBTBMissBubble = Wire(Bool())
  val TAGEMissBubble = Wire(Bool())
  val SCMissBubble = Wire(Bool())
  val ITTAGEMissBubble = Wire(Bool())
  val RASMissBubble = Wire(Bool())

  val memVioRedirectBubble = Wire(Bool())
  val otherRedirectBubble = Wire(Bool())
  val btbMissBubble = Wire(Bool())
  otherRedirectBubble := false.B
  memVioRedirectBubble := false.B

  // override can happen between s1-s2 and s2-s3
  val overrideBubble = Wire(Vec(numOfStage - 1, Bool()))
  def overrideStage = 1
  // ftq update block can happen on s1, s2 and s3
  val ftqUpdateBubble = Wire(Vec(numOfStage, Bool()))
  def ftqUpdateStage = 0
  // ftq full stall only happens on s3 (last stage)
  val ftqFullStall = Wire(Bool())

  // by default, no bubble event
  topdown_stages(0) := 0.U.asTypeOf(new FrontendTopDownBundle)
  // event movement driven by clock only
  for (i <- 0 until numOfStage - 1) {
    topdown_stages(i + 1) := topdown_stages(i)
  }


  // ctrl signal
  predictors.io.ctrl := ctrl
  predictors.io.reset_vector := io.reset_vector


  val (_, reset_vector) = DelayNWithValid(io.reset_vector, reset.asBool, 5, hasInit = false)

  val s0_stall_dup = dup_wire(Bool()) // For some reason s0 stalled, usually FTQ Full
  val s0_fire_dup, s1_fire_dup, s2_fire_dup, s3_fire_dup = dup_wire(Bool())
  val s1_valid_dup, s2_valid_dup, s3_valid_dup = dup_seq(RegInit(false.B))
  val s1_ready_dup, s2_ready_dup, s3_ready_dup = dup_wire(Bool())
  val s1_components_ready_dup, s2_components_ready_dup, s3_components_ready_dup = dup_wire(Bool())

  val s0_pc_dup = dup(WireInit(0.U.asTypeOf(UInt(VAddrBits.W))))
  val s0_pc_reg_dup = s0_pc_dup.zip(s0_stall_dup).map{ case (s0_pc, s0_stall) => RegEnable(s0_pc, !s0_stall) }
  when (RegNext(RegNext(reset.asBool) && !reset.asBool)) {
    s0_pc_reg_dup.map{case s0_pc => s0_pc := reset_vector}
  }
  val s1_pc = RegEnable(s0_pc_dup(0), s0_fire_dup(0))
  val s2_pc = RegEnable(s1_pc, s1_fire_dup(0))
  val s3_pc = RegEnable(s2_pc, s2_fire_dup(0))

  val s0_folded_gh_dup = dup_wire(new AllFoldedHistories(foldedGHistInfos))
  val s0_folded_gh_reg_dup = s0_folded_gh_dup.zip(s0_stall_dup).map{
    case (x, s0_stall) => RegEnable(x, 0.U.asTypeOf(s0_folded_gh_dup(0)), !s0_stall)
  }
  val s1_folded_gh_dup = RegEnable(s0_folded_gh_dup, 0.U.asTypeOf(s0_folded_gh_dup), s0_fire_dup(1))
  val s2_folded_gh_dup = RegEnable(s1_folded_gh_dup, 0.U.asTypeOf(s0_folded_gh_dup), s1_fire_dup(1))
  val s3_folded_gh_dup = RegEnable(s2_folded_gh_dup, 0.U.asTypeOf(s0_folded_gh_dup), s2_fire_dup(1))

  val s0_last_br_num_oh_dup = dup_wire(UInt((numBr+1).W))
  val s0_last_br_num_oh_reg_dup = s0_last_br_num_oh_dup.zip(s0_stall_dup).map{
    case (x, s0_stall) => RegEnable(x, 0.U, !s0_stall)
  }
  val s1_last_br_num_oh_dup = RegEnable(s0_last_br_num_oh_dup, 0.U.asTypeOf(s0_last_br_num_oh_dup), s0_fire_dup(1))
  val s2_last_br_num_oh_dup = RegEnable(s1_last_br_num_oh_dup, 0.U.asTypeOf(s0_last_br_num_oh_dup), s1_fire_dup(1))
  val s3_last_br_num_oh_dup = RegEnable(s2_last_br_num_oh_dup, 0.U.asTypeOf(s0_last_br_num_oh_dup), s2_fire_dup(1))

  val s0_ahead_fh_oldest_bits_dup = dup_wire(new AllAheadFoldedHistoryOldestBits(foldedGHistInfos))
  val s0_ahead_fh_oldest_bits_reg_dup = s0_ahead_fh_oldest_bits_dup.zip(s0_stall_dup).map{
    case (x, s0_stall) => RegEnable(x, 0.U.asTypeOf(s0_ahead_fh_oldest_bits_dup(0)), !s0_stall)
  }
  val s1_ahead_fh_oldest_bits_dup = RegEnable(s0_ahead_fh_oldest_bits_dup, 0.U.asTypeOf(s0_ahead_fh_oldest_bits_dup), s0_fire_dup(1))
  val s2_ahead_fh_oldest_bits_dup = RegEnable(s1_ahead_fh_oldest_bits_dup, 0.U.asTypeOf(s0_ahead_fh_oldest_bits_dup), s1_fire_dup(1))
  val s3_ahead_fh_oldest_bits_dup = RegEnable(s2_ahead_fh_oldest_bits_dup, 0.U.asTypeOf(s0_ahead_fh_oldest_bits_dup), s2_fire_dup(1))

  val npcGen_dup         = Seq.tabulate(numDup)(n => new PhyPriorityMuxGenerator[UInt])
  val foldedGhGen_dup    = Seq.tabulate(numDup)(n => new PhyPriorityMuxGenerator[AllFoldedHistories])
  val ghistPtrGen_dup    = Seq.tabulate(numDup)(n => new PhyPriorityMuxGenerator[CGHPtr])
  val lastBrNumOHGen_dup = Seq.tabulate(numDup)(n => new PhyPriorityMuxGenerator[UInt])
  val aheadFhObGen_dup   = Seq.tabulate(numDup)(n => new PhyPriorityMuxGenerator[AllAheadFoldedHistoryOldestBits])

  val ghvBitWriteGens = Seq.tabulate(HistoryLength)(n => new PhyPriorityMuxGenerator[Bool])
  // val ghistGen = new PhyPriorityMuxGenerator[UInt]

  val ghv = RegInit(0.U.asTypeOf(Vec(HistoryLength, Bool())))
  val ghv_wire = WireInit(ghv)

  val s0_ghist = WireInit(0.U.asTypeOf(UInt(HistoryLength.W)))


  println(f"history buffer length ${HistoryLength}")
  val ghv_write_datas = Wire(Vec(HistoryLength, Bool()))
  val ghv_wens = Wire(Vec(HistoryLength, Bool()))

  val s0_ghist_ptr_dup = dup_wire(new CGHPtr)
  val s0_ghist_ptr_reg_dup = s0_ghist_ptr_dup.zip(s0_stall_dup).map{
    case (x, s0_stall) => RegEnable(x, 0.U.asTypeOf(new CGHPtr), !s0_stall)
  }
  val s1_ghist_ptr_dup = RegEnable(s0_ghist_ptr_dup, 0.U.asTypeOf(s0_ghist_ptr_dup), s0_fire_dup(1))
  val s2_ghist_ptr_dup = RegEnable(s1_ghist_ptr_dup, 0.U.asTypeOf(s0_ghist_ptr_dup), s1_fire_dup(1))
  val s3_ghist_ptr_dup = RegEnable(s2_ghist_ptr_dup, 0.U.asTypeOf(s0_ghist_ptr_dup), s2_fire_dup(1))

  def getHist(ptr: CGHPtr): UInt = (Cat(ghv_wire.asUInt, ghv_wire.asUInt) >> (ptr.value+1.U))(HistoryLength-1, 0)
  s0_ghist := getHist(s0_ghist_ptr_dup(0))

  val resp = predictors.io.out


  val toFtq_fire = io.bpu_to_ftq.resp.valid && io.bpu_to_ftq.resp.ready

  val s1_flush_dup, s2_flush_dup, s3_flush_dup = dup_wire(Bool())
  val s2_redirect_dup, s3_redirect_dup = dup_wire(Bool())

  // predictors.io := DontCare
  predictors.io.in.valid := s0_fire_dup(0)
  predictors.io.in.bits.s0_pc := s0_pc_dup
  predictors.io.in.bits.ghist := s0_ghist
  predictors.io.in.bits.folded_hist := s0_folded_gh_dup
  predictors.io.in.bits.s1_folded_hist := s1_folded_gh_dup
  predictors.io.in.bits.resp_in(0) := (0.U).asTypeOf(new BranchPredictionResp)
  predictors.io.fauftb_entry_in := (0.U).asTypeOf(new FTBEntry)
  predictors.io.fauftb_entry_hit_in := false.B
  predictors.io.redirectFromIFU := RegNext(io.ftq_to_bpu.redirctFromIFU, init=false.B)
  // predictors.io.in.bits.resp_in(0).s1.pc := s0_pc
  // predictors.io.in.bits.toFtq_fire := toFtq_fire

  // predictors.io.out.ready := io.bpu_to_ftq.resp.ready

  val redirect_req = io.ftq_to_bpu.redirect
  val do_redirect_dup = dup_seq(RegNextWithEnable(redirect_req))

  // Pipeline logic
  s2_redirect_dup.map(_ := false.B)
  s3_redirect_dup.map(_ := false.B)

  s3_flush_dup.map(_ := redirect_req.valid) // flush when redirect comes
  for (((s2_flush, s3_flush), s3_redirect) <- s2_flush_dup zip s3_flush_dup zip s3_redirect_dup)
    s2_flush := s3_flush || s3_redirect
  for (((s1_flush, s2_flush), s2_redirect) <- s1_flush_dup zip s2_flush_dup zip s2_redirect_dup)
    s1_flush := s2_flush || s2_redirect


  s1_components_ready_dup.map(_ := predictors.io.s1_ready)
  for (((s1_ready, s1_fire), s1_valid) <- s1_ready_dup zip s1_fire_dup zip s1_valid_dup)
    s1_ready := s1_fire || !s1_valid
  for (((s0_fire, s1_components_ready), s1_ready) <- s0_fire_dup zip s1_components_ready_dup zip s1_ready_dup)
    s0_fire := s1_components_ready && s1_ready
  predictors.io.s0_fire := s0_fire_dup

  s2_components_ready_dup.map(_ := predictors.io.s2_ready)
  for (((s2_ready, s2_fire), s2_valid) <- s2_ready_dup zip s2_fire_dup zip s2_valid_dup)
    s2_ready := s2_fire || !s2_valid
  for ((((s1_fire, s2_components_ready), s2_ready), s1_valid) <- s1_fire_dup zip s2_components_ready_dup zip s2_ready_dup zip s1_valid_dup)
    s1_fire := s1_valid && s2_components_ready && s2_ready && io.bpu_to_ftq.resp.ready

  s3_components_ready_dup.map(_ := predictors.io.s3_ready)
  for (((s3_ready, s3_fire), s3_valid) <- s3_ready_dup zip s3_fire_dup zip s3_valid_dup)
    s3_ready := s3_fire || !s3_valid
  for ((((s2_fire, s3_components_ready), s3_ready), s2_valid) <- s2_fire_dup zip s3_components_ready_dup zip s3_ready_dup zip s2_valid_dup)
    s2_fire := s2_valid && s3_components_ready && s3_ready

  for ((((s0_fire, s1_flush), s1_fire), s1_valid) <- s0_fire_dup zip s1_flush_dup zip s1_fire_dup zip s1_valid_dup) {
    when (redirect_req.valid) { s1_valid := false.B }
      .elsewhen(s0_fire)      { s1_valid := true.B  }
      .elsewhen(s1_flush)     { s1_valid := false.B }
      .elsewhen(s1_fire)      { s1_valid := false.B }
  }
  predictors.io.s1_fire := s1_fire_dup

  s2_fire_dup := s2_valid_dup

  for (((((s1_fire, s2_flush), s2_fire), s2_valid), s1_flush) <-
    s1_fire_dup zip s2_flush_dup zip s2_fire_dup zip s2_valid_dup zip s1_flush_dup) {

    when (s2_flush)      { s2_valid := false.B   }
      .elsewhen(s1_fire) { s2_valid := !s1_flush }
      .elsewhen(s2_fire) { s2_valid := false.B   }
  }

  predictors.io.s2_fire := s2_fire_dup
  predictors.io.s2_redirect := s2_redirect_dup

  s3_fire_dup := s3_valid_dup

  for (((((s2_fire, s3_flush), s3_fire), s3_valid), s2_flush) <-
    s2_fire_dup zip s3_flush_dup zip s3_fire_dup zip s3_valid_dup zip s2_flush_dup) {

    when (s3_flush)      { s3_valid := false.B   }
      .elsewhen(s2_fire) { s3_valid := !s2_flush }
      .elsewhen(s3_fire) { s3_valid := false.B   }
  }

  predictors.io.s3_fire := s3_fire_dup
  predictors.io.s3_redirect := s3_redirect_dup


  io.bpu_to_ftq.resp.valid :=
    s1_valid_dup(2) && s2_components_ready_dup(2) && s2_ready_dup(2) ||
    s2_fire_dup(2) && s2_redirect_dup(2) ||
    s3_fire_dup(2) && s3_redirect_dup(2)
  io.bpu_to_ftq.resp.bits  := predictors.io.out
  io.bpu_to_ftq.resp.bits.last_stage_spec_info.histPtr     := s3_ghist_ptr_dup(2)

  val full_pred_diff = WireInit(false.B)
  val full_pred_diff_stage = WireInit(0.U)
  val full_pred_diff_offset = WireInit(0.U)
  for (i <- 0 until numDup - 1) {
    when (io.bpu_to_ftq.resp.valid &&
      ((io.bpu_to_ftq.resp.bits.s1.full_pred(i).asTypeOf(UInt()) =/= io.bpu_to_ftq.resp.bits.s1.full_pred(i+1).asTypeOf(UInt()) && io.bpu_to_ftq.resp.bits.s1.full_pred(i).hit) ||
          (io.bpu_to_ftq.resp.bits.s2.full_pred(i).asTypeOf(UInt()) =/= io.bpu_to_ftq.resp.bits.s2.full_pred(i+1).asTypeOf(UInt()) && io.bpu_to_ftq.resp.bits.s2.full_pred(i).hit) ||
          (io.bpu_to_ftq.resp.bits.s3.full_pred(i).asTypeOf(UInt()) =/= io.bpu_to_ftq.resp.bits.s3.full_pred(i+1).asTypeOf(UInt()) && io.bpu_to_ftq.resp.bits.s3.full_pred(i).hit))) {
      full_pred_diff := true.B
      full_pred_diff_offset := i.U
      when (io.bpu_to_ftq.resp.bits.s1.full_pred(i).asTypeOf(UInt()) =/= io.bpu_to_ftq.resp.bits.s1.full_pred(i+1).asTypeOf(UInt())) {
        full_pred_diff_stage := 1.U
      } .elsewhen (io.bpu_to_ftq.resp.bits.s2.full_pred(i).asTypeOf(UInt()) =/= io.bpu_to_ftq.resp.bits.s2.full_pred(i+1).asTypeOf(UInt())) {
        full_pred_diff_stage := 2.U
      } .otherwise {
        full_pred_diff_stage := 3.U
      }
    }
  }
  XSError(full_pred_diff, "Full prediction difference detected!")

  // s0_stall should be exclusive with any other PC source
  s0_stall_dup.zip(s1_valid_dup).zip(s2_redirect_dup).zip(s3_redirect_dup).zip(do_redirect_dup).foreach {
    case ((((s0_stall, s1_valid), s2_redirect), s3_redirect), do_redirect) => {
      s0_stall := !(s1_valid || s2_redirect || s3_redirect || do_redirect.valid)
    }
  }
  // Power-on reset
  val powerOnResetState = RegInit(true.B)
  when(s0_fire_dup(0)) {
    // When BPU pipeline first time fire, we consider power-on reset is done
    powerOnResetState := false.B
  }
  XSError(!powerOnResetState && s0_stall_dup(0) && s0_pc_dup(0) =/= s0_pc_reg_dup(0), "s0_stall but s0_pc is differenct from s0_pc_reg")

  npcGen_dup.zip(s0_pc_reg_dup).map{ case (gen, reg) =>
    gen.register(true.B, reg, Some("stallPC"), 0)}
  foldedGhGen_dup.zip(s0_folded_gh_reg_dup).map{ case (gen, reg) =>
    gen.register(true.B, reg, Some("stallFGH"), 0)}
  ghistPtrGen_dup.zip(s0_ghist_ptr_reg_dup).map{ case (gen, reg) =>
    gen.register(true.B, reg, Some("stallGHPtr"), 0)}
  lastBrNumOHGen_dup.zip(s0_last_br_num_oh_reg_dup).map{ case (gen, reg) =>
    gen.register(true.B, reg, Some("stallBrNumOH"), 0)}
  aheadFhObGen_dup.zip(s0_ahead_fh_oldest_bits_reg_dup).map{ case (gen, reg) =>
    gen.register(true.B, reg, Some("stallAFHOB"), 0)}

  // assign pred cycle for profiling
  io.bpu_to_ftq.resp.bits.s1.full_pred.map(_.predCycle.map(_ := GTimer()))
  io.bpu_to_ftq.resp.bits.s2.full_pred.map(_.predCycle.map(_ := GTimer()))
  io.bpu_to_ftq.resp.bits.s3.full_pred.map(_.predCycle.map(_ := GTimer()))


  // History manage
  // s1
  val s1_possible_predicted_ghist_ptrs_dup = s1_ghist_ptr_dup.map(ptr => (0 to numBr).map(ptr - _.U))
  val s1_predicted_ghist_ptr_dup = s1_possible_predicted_ghist_ptrs_dup.zip(resp.s1.lastBrPosOH).map{ case (ptr, oh) => Mux1H(oh, ptr)}
  val s1_possible_predicted_fhs_dup =
    for (((((fgh, afh), br_num_oh), t), br_pos_oh) <-
      s1_folded_gh_dup zip s1_ahead_fh_oldest_bits_dup zip s1_last_br_num_oh_dup zip resp.s1.brTaken zip resp.s1.lastBrPosOH)
      yield (0 to numBr).map(i =>
        fgh.update(afh, br_num_oh, i, t & br_pos_oh(i))
      )
  val s1_predicted_fh_dup = resp.s1.lastBrPosOH.zip(s1_possible_predicted_fhs_dup).map{ case (oh, fh) => Mux1H(oh, fh)}

  val s1_ahead_fh_ob_src_dup = dup_wire(new AllAheadFoldedHistoryOldestBits(foldedGHistInfos))
  s1_ahead_fh_ob_src_dup.zip(s1_ghist_ptr_dup).map{ case (src, ptr) => src.read(ghv, ptr)}

  if (EnableGHistDiff) {
    val s1_predicted_ghist = WireInit(getHist(s1_predicted_ghist_ptr_dup(0)).asTypeOf(Vec(HistoryLength, Bool())))
    for (i <- 0 until numBr) {
      when (resp.s1.shouldShiftVec(0)(i)) {
        s1_predicted_ghist(i) := resp.s1.brTaken(0) && (i==0).B
      }
    }
    when (s1_valid_dup(0)) {
      s0_ghist := s1_predicted_ghist.asUInt
    }
  }

  val s1_ghv_wens = (0 until HistoryLength).map(n =>
    (0 until numBr).map(b => (s1_ghist_ptr_dup(0)).value === (CGHPtr(false.B, n.U) + b.U).value && resp.s1.shouldShiftVec(0)(b) && s1_valid_dup(0)))
  val s1_ghv_wdatas = (0 until HistoryLength).map(n =>
    Mux1H(
      (0 until numBr).map(b => (
        (s1_ghist_ptr_dup(0)).value === (CGHPtr(false.B, n.U) + b.U).value && resp.s1.shouldShiftVec(0)(b),
        resp.s1.brTaken(0) && resp.s1.lastBrPosOH(0)(b+1)
      ))
    )
  )


  for (((npcGen, s1_valid), s1_target) <- npcGen_dup zip s1_valid_dup zip resp.s1.getTarget)
    npcGen.register(s1_valid, s1_target, Some("s1_target"), 4)
  for (((foldedGhGen, s1_valid), s1_predicted_fh) <- foldedGhGen_dup zip s1_valid_dup zip s1_predicted_fh_dup)
    foldedGhGen.register(s1_valid, s1_predicted_fh, Some("s1_FGH"), 4)
  for (((ghistPtrGen, s1_valid), s1_predicted_ghist_ptr) <- ghistPtrGen_dup zip s1_valid_dup zip s1_predicted_ghist_ptr_dup)
    ghistPtrGen.register(s1_valid, s1_predicted_ghist_ptr, Some("s1_GHPtr"), 4)
  for (((lastBrNumOHGen, s1_valid), s1_brPosOH) <- lastBrNumOHGen_dup zip s1_valid_dup zip resp.s1.lastBrPosOH.map(_.asUInt))
    lastBrNumOHGen.register(s1_valid, s1_brPosOH, Some("s1_BrNumOH"), 4)
  for (((aheadFhObGen, s1_valid), s1_ahead_fh_ob_src) <- aheadFhObGen_dup zip s1_valid_dup zip s1_ahead_fh_ob_src_dup)
    aheadFhObGen.register(s1_valid, s1_ahead_fh_ob_src, Some("s1_AFHOB"), 4)
  ghvBitWriteGens.zip(s1_ghv_wens).zipWithIndex.map{case ((b, w), i) =>
    b.register(w.reduce(_||_), s1_ghv_wdatas(i), Some(s"s1_new_bit_$i"), 4)
  }

  class PreviousPredInfo extends Bundle {
    val hit = Vec(numDup, Bool())
    val target = Vec(numDup, UInt(VAddrBits.W))
    val lastBrPosOH = Vec(numDup, Vec(numBr+1, Bool()))
    val taken = Vec(numDup, Bool())
    val takenMask = Vec(numDup, Vec(numBr, Bool()))
    val cfiIndex = Vec(numDup, UInt(log2Ceil(PredictWidth).W))
  }

  def preds_needs_redirect_vec_dup(x: PreviousPredInfo, y: BranchPredictionBundle) = {
    // Timing optimization
    // We first compare all target with previous stage target,
    // then select the difference by taken & hit
    // Usually target is generated quicker than taken, so do target compare before select can help timing
    val targetDiffVec: IndexedSeq[Vec[Bool]] =
      x.target.zip(y.getAllTargets).map {
        case (xTarget, yAllTarget) => VecInit(yAllTarget.map(_ =/= xTarget))
      } // [numDup][all Target comparison]
    val targetDiff   : IndexedSeq[Bool]      =
      targetDiffVec.zip(x.hit).zip(x.takenMask).map {
        case ((diff, hit), takenMask) => selectByTaken(takenMask, hit, diff)
      } // [numDup]

    val lastBrPosOHDiff: IndexedSeq[Bool]      = x.lastBrPosOH.zip(y.lastBrPosOH).map { case (oh1, oh2) => oh1.asUInt =/= oh2.asUInt }
    val takenDiff      : IndexedSeq[Bool]      = x.taken.zip(y.taken).map { case (t1, t2) => t1 =/= t2 }
    val takenOffsetDiff: IndexedSeq[Bool]      = x.cfiIndex.zip(y.cfiIndex).zip(x.taken).zip(y.taken).map { case (((i1, i2), xt), yt) => xt && yt && i1 =/= i2.bits }
    VecInit(
      for ((((tgtd, lbpohd), tkd), tod) <-
             targetDiff zip lastBrPosOHDiff zip takenDiff zip takenOffsetDiff)
      yield VecInit(tgtd, lbpohd, tkd, tod)
      // x.shouldShiftVec.asUInt =/= y.shouldShiftVec.asUInt,
      // x.brTaken =/= y.brTaken
    )
  }

  // s2
  val s2_possible_predicted_ghist_ptrs_dup = s2_ghist_ptr_dup.map(ptr => (0 to numBr).map(ptr - _.U))
  val s2_predicted_ghist_ptr_dup = s2_possible_predicted_ghist_ptrs_dup.zip(resp.s2.lastBrPosOH).map{ case (ptr, oh) => Mux1H(oh, ptr)}

  val s2_possible_predicted_fhs_dup =
    for ((((fgh, afh), br_num_oh), full_pred) <-
      s2_folded_gh_dup zip s2_ahead_fh_oldest_bits_dup zip s2_last_br_num_oh_dup zip resp.s2.full_pred)
      yield (0 to numBr).map(i =>
        fgh.update(afh, br_num_oh, i, if (i > 0) full_pred.br_taken_mask(i-1) else false.B)
      )
  val s2_predicted_fh_dup = resp.s2.lastBrPosOH.zip(s2_possible_predicted_fhs_dup).map{ case (oh, fh) => Mux1H(oh, fh)}

  val s2_ahead_fh_ob_src_dup = dup_wire(new AllAheadFoldedHistoryOldestBits(foldedGHistInfos))
  s2_ahead_fh_ob_src_dup.zip(s2_ghist_ptr_dup).map{ case (src, ptr) => src.read(ghv, ptr)}

  if (EnableGHistDiff) {
    val s2_predicted_ghist = WireInit(getHist(s2_predicted_ghist_ptr_dup(0)).asTypeOf(Vec(HistoryLength, Bool())))
    for (i <- 0 until numBr) {
      when (resp.s2.shouldShiftVec(0)(i)) {
        s2_predicted_ghist(i) := resp.s2.brTaken(0) && (i==0).B
      }
    }
    when(s2_redirect_dup(0)) {
      s0_ghist := s2_predicted_ghist.asUInt
    }
  }

  val s2_ghv_wens = (0 until HistoryLength).map(n =>
    (0 until numBr).map(b => (s2_ghist_ptr_dup(0)).value === (CGHPtr(false.B, n.U) + b.U).value && resp.s2.shouldShiftVec(0)(b) && s2_redirect_dup(0)))
  val s2_ghv_wdatas = (0 until HistoryLength).map(n =>
    Mux1H(
      (0 until numBr).map(b => (
        (s2_ghist_ptr_dup(0)).value === (CGHPtr(false.B, n.U) + b.U).value && resp.s2.shouldShiftVec(0)(b),
        resp.s2.full_pred(0).real_br_taken_mask()(b)
      ))
    )
  )

  val s1_pred_info = Wire(new PreviousPredInfo)
  s1_pred_info.hit := resp.s1.full_pred.map(_.hit)
  s1_pred_info.target := resp.s1.getTarget
  s1_pred_info.lastBrPosOH := resp.s1.lastBrPosOH
  s1_pred_info.taken := resp.s1.taken
  s1_pred_info.takenMask := resp.s1.full_pred.map(_.taken_mask_on_slot)
  s1_pred_info.cfiIndex := resp.s1.cfiIndex.map { case x => x.bits }

  val previous_s1_pred_info = RegEnable(s1_pred_info, 0.U.asTypeOf(new PreviousPredInfo), s1_fire_dup(0))

  val s2_redirect_s1_last_pred_vec_dup = preds_needs_redirect_vec_dup(previous_s1_pred_info, resp.s2)

  for (((s2_redirect, s2_fire), s2_redirect_s1_last_pred_vec) <- s2_redirect_dup zip s2_fire_dup zip s2_redirect_s1_last_pred_vec_dup)
    s2_redirect := s2_fire && s2_redirect_s1_last_pred_vec.reduce(_||_)


  for (((npcGen, s2_redirect), s2_target) <- npcGen_dup zip s2_redirect_dup zip resp.s2.getTarget)
    npcGen.register(s2_redirect, s2_target, Some("s2_target"), 5)
  for (((foldedGhGen, s2_redirect), s2_predicted_fh) <- foldedGhGen_dup zip s2_redirect_dup zip s2_predicted_fh_dup)
    foldedGhGen.register(s2_redirect, s2_predicted_fh, Some("s2_FGH"), 5)
  for (((ghistPtrGen, s2_redirect), s2_predicted_ghist_ptr) <- ghistPtrGen_dup zip s2_redirect_dup zip s2_predicted_ghist_ptr_dup)
    ghistPtrGen.register(s2_redirect, s2_predicted_ghist_ptr, Some("s2_GHPtr"), 5)
  for (((lastBrNumOHGen, s2_redirect), s2_brPosOH) <- lastBrNumOHGen_dup zip s2_redirect_dup zip resp.s2.lastBrPosOH.map(_.asUInt))
    lastBrNumOHGen.register(s2_redirect, s2_brPosOH, Some("s2_BrNumOH"), 5)
  for (((aheadFhObGen, s2_redirect), s2_ahead_fh_ob_src) <- aheadFhObGen_dup zip s2_redirect_dup zip s2_ahead_fh_ob_src_dup)
    aheadFhObGen.register(s2_redirect, s2_ahead_fh_ob_src, Some("s2_AFHOB"), 5)
  ghvBitWriteGens.zip(s2_ghv_wens).zipWithIndex.map{case ((b, w), i) =>
    b.register(w.reduce(_||_), s2_ghv_wdatas(i), Some(s"s2_new_bit_$i"), 5)
  }

  XSPerfAccumulate("s2_redirect_because_target_diff", s2_fire_dup(0) && s2_redirect_s1_last_pred_vec_dup(0)(0))
  XSPerfAccumulate("s2_redirect_because_branch_num_diff", s2_fire_dup(0) && s2_redirect_s1_last_pred_vec_dup(0)(1))
  XSPerfAccumulate("s2_redirect_because_direction_diff", s2_fire_dup(0) && s2_redirect_s1_last_pred_vec_dup(0)(2))
  XSPerfAccumulate("s2_redirect_because_cfi_idx_diff", s2_fire_dup(0) && s2_redirect_s1_last_pred_vec_dup(0)(3))
  // XSPerfAccumulate("s2_redirect_because_shouldShiftVec_diff", s2_fire && s2_redirect_s1_last_pred_vec(4))
  // XSPerfAccumulate("s2_redirect_because_brTaken_diff", s2_fire && s2_redirect_s1_last_pred_vec(5))
  XSPerfAccumulate("s2_redirect_because_fallThroughError", s2_fire_dup(0) && resp.s2.fallThruError(0))

  XSPerfAccumulate("s2_redirect_when_taken", s2_redirect_dup(0) && resp.s2.taken(0) && resp.s2.full_pred(0).hit)
  XSPerfAccumulate("s2_redirect_when_not_taken", s2_redirect_dup(0) && !resp.s2.taken(0) && resp.s2.full_pred(0).hit)
  XSPerfAccumulate("s2_redirect_when_not_hit", s2_redirect_dup(0) && !resp.s2.full_pred(0).hit)


  // s3
  val s3_possible_predicted_ghist_ptrs_dup = s3_ghist_ptr_dup.map(ptr => (0 to numBr).map(ptr - _.U))
  val s3_predicted_ghist_ptr_dup = s3_possible_predicted_ghist_ptrs_dup.zip(resp.s3.lastBrPosOH).map{ case (ptr, oh) => Mux1H(oh, ptr)}

  val s3_possible_predicted_fhs_dup =
    for ((((fgh, afh), br_num_oh), full_pred) <-
      s3_folded_gh_dup zip s3_ahead_fh_oldest_bits_dup zip s3_last_br_num_oh_dup zip resp.s3.full_pred)
      yield (0 to numBr).map(i =>
        fgh.update(afh, br_num_oh, i, if (i > 0) full_pred.br_taken_mask(i-1) else false.B)
      )
  val s3_predicted_fh_dup = resp.s3.lastBrPosOH.zip(s3_possible_predicted_fhs_dup).map{ case (oh, fh) => Mux1H(oh, fh)}

  val s3_ahead_fh_ob_src_dup = dup_wire(new AllAheadFoldedHistoryOldestBits(foldedGHistInfos))
  s3_ahead_fh_ob_src_dup.zip(s3_ghist_ptr_dup).map{ case (src, ptr) => src.read(ghv, ptr)}

  if (EnableGHistDiff) {
    val s3_predicted_ghist = WireInit(getHist(s3_predicted_ghist_ptr_dup(0)).asTypeOf(Vec(HistoryLength, Bool())))
    for (i <- 0 until numBr) {
      when (resp.s3.shouldShiftVec(0)(i)) {
        s3_predicted_ghist(i) := resp.s3.brTaken(0) && (i==0).B
      }
    }
    when(s3_redirect_dup(0)) {
      s0_ghist := s3_predicted_ghist.asUInt
    }
  }

  val s3_ghv_wens = (0 until HistoryLength).map(n =>
    (0 until numBr).map(b => (s3_ghist_ptr_dup(0)).value === (CGHPtr(false.B, n.U) + b.U).value && resp.s3.shouldShiftVec(0)(b) && s3_redirect_dup(0)))
  val s3_ghv_wdatas = (0 until HistoryLength).map(n =>
    Mux1H(
      (0 until numBr).map(b => (
        (s3_ghist_ptr_dup(0)).value === (CGHPtr(false.B, n.U) + b.U).value && resp.s3.shouldShiftVec(0)(b),
        resp.s3.full_pred(0).real_br_taken_mask()(b)
      ))
    )
  )

  val previous_s2_pred = RegEnable(resp.s2, 0.U.asTypeOf(resp.s2), s2_fire_dup(0))

  val s3_redirect_on_br_taken_dup = resp.s3.full_pred.zip(previous_s2_pred.full_pred).map {case (fp1, fp2) => fp1.real_br_taken_mask().asUInt =/= fp2.real_br_taken_mask().asUInt}
  val s3_both_first_taken_dup = resp.s3.full_pred.zip(previous_s2_pred.full_pred).map {case (fp1, fp2) => fp1.real_br_taken_mask()(0) && fp2.real_br_taken_mask()(0)}
  val s3_redirect_on_target_dup = resp.s3.getTarget.zip(previous_s2_pred.getTarget).map {case (t1, t2) => t1 =/= t2}
  val s3_redirect_on_jalr_target_dup = resp.s3.full_pred.zip(previous_s2_pred.full_pred).map {case (fp1, fp2) => fp1.hit_taken_on_jalr && fp1.jalr_target =/= fp2.jalr_target}
  val s3_redirect_on_fall_thru_error_dup = resp.s3.fallThruError
  val s3_redirect_on_ftb_multi_hit_dup = resp.s3.ftbMultiHit

  for (((((((s3_redirect, s3_fire), s3_redirect_on_br_taken), s3_redirect_on_target), s3_redirect_on_fall_thru_error), s3_redirect_on_ftb_multi_hit), s3_both_first_taken) <-
    s3_redirect_dup zip s3_fire_dup zip s3_redirect_on_br_taken_dup zip s3_redirect_on_target_dup zip s3_redirect_on_fall_thru_error_dup zip s3_redirect_on_ftb_multi_hit_dup zip s3_both_first_taken_dup) {

    s3_redirect := s3_fire && (
      (s3_redirect_on_br_taken && !s3_both_first_taken) || s3_redirect_on_target || s3_redirect_on_fall_thru_error || s3_redirect_on_ftb_multi_hit
    )
  }

  XSPerfAccumulate(f"s3_redirect_on_br_taken", s3_fire_dup(0) && s3_redirect_on_br_taken_dup(0))
  XSPerfAccumulate(f"s3_redirect_on_jalr_target", s3_fire_dup(0) && s3_redirect_on_jalr_target_dup(0))
  XSPerfAccumulate(f"s3_redirect_on_others", s3_redirect_dup(0) && !(s3_redirect_on_br_taken_dup(0) || s3_redirect_on_jalr_target_dup(0)))

  for (((npcGen, s3_redirect), s3_target) <- npcGen_dup zip s3_redirect_dup zip resp.s3.getTarget)
    npcGen.register(s3_redirect, s3_target, Some("s3_target"), 3)
  for (((foldedGhGen, s3_redirect), s3_predicted_fh) <- foldedGhGen_dup zip s3_redirect_dup zip s3_predicted_fh_dup)
    foldedGhGen.register(s3_redirect, s3_predicted_fh, Some("s3_FGH"), 3)
  for (((ghistPtrGen, s3_redirect), s3_predicted_ghist_ptr) <- ghistPtrGen_dup zip s3_redirect_dup zip s3_predicted_ghist_ptr_dup)
    ghistPtrGen.register(s3_redirect, s3_predicted_ghist_ptr, Some("s3_GHPtr"), 3)
  for (((lastBrNumOHGen, s3_redirect), s3_brPosOH) <- lastBrNumOHGen_dup zip s3_redirect_dup zip resp.s3.lastBrPosOH.map(_.asUInt))
    lastBrNumOHGen.register(s3_redirect, s3_brPosOH, Some("s3_BrNumOH"), 3)
  for (((aheadFhObGen, s3_redirect), s3_ahead_fh_ob_src) <- aheadFhObGen_dup zip s3_redirect_dup zip s3_ahead_fh_ob_src_dup)
    aheadFhObGen.register(s3_redirect, s3_ahead_fh_ob_src, Some("s3_AFHOB"), 3)
  ghvBitWriteGens.zip(s3_ghv_wens).zipWithIndex.map{case ((b, w), i) =>
    b.register(w.reduce(_||_), s3_ghv_wdatas(i), Some(s"s3_new_bit_$i"), 3)
  }

  // Send signal tell Ftq override
  val s2_ftq_idx = RegEnable(io.ftq_to_bpu.enq_ptr, s1_fire_dup(0))
  val s3_ftq_idx = RegEnable(s2_ftq_idx, s2_fire_dup(0))

  for (((to_ftq_s1_valid, s1_fire), s1_flush) <- io.bpu_to_ftq.resp.bits.s1.valid zip s1_fire_dup zip s1_flush_dup) {
    to_ftq_s1_valid := s1_fire && !s1_flush
  }
  io.bpu_to_ftq.resp.bits.s1.hasRedirect.map(_ := false.B)
  io.bpu_to_ftq.resp.bits.s1.ftq_idx := DontCare
  for (((to_ftq_s2_valid, s2_fire), s2_flush) <- io.bpu_to_ftq.resp.bits.s2.valid zip s2_fire_dup zip s2_flush_dup) {
    to_ftq_s2_valid := s2_fire && !s2_flush
  }
  io.bpu_to_ftq.resp.bits.s2.hasRedirect.zip(s2_redirect_dup).map {case (hr, r) => hr := r}
  io.bpu_to_ftq.resp.bits.s2.ftq_idx := s2_ftq_idx
  for (((to_ftq_s3_valid, s3_fire), s3_flush) <- io.bpu_to_ftq.resp.bits.s3.valid zip s3_fire_dup zip s3_flush_dup) {
    to_ftq_s3_valid := s3_fire && !s3_flush
  }
  io.bpu_to_ftq.resp.bits.s3.hasRedirect.zip(s3_redirect_dup).map {case (hr, r) => hr := r}
  io.bpu_to_ftq.resp.bits.s3.ftq_idx := s3_ftq_idx

  predictors.io.update.valid := RegNext(io.ftq_to_bpu.update.valid, init = false.B)
  predictors.io.update.bits := RegEnable(io.ftq_to_bpu.update.bits, io.ftq_to_bpu.update.valid)
  predictors.io.update.bits.ghist := RegEnable(
    getHist(io.ftq_to_bpu.update.bits.spec_info.histPtr), io.ftq_to_bpu.update.valid)

  val redirect_dup = do_redirect_dup.map(_.bits)
  predictors.io.redirect := do_redirect_dup(0)

  // Redirect logic
  val shift_dup = redirect_dup.map(_.cfiUpdate.shift)
  val addIntoHist_dup = redirect_dup.map(_.cfiUpdate.addIntoHist)
  // TODO: remove these below
  val shouldShiftVec_dup = shift_dup.map(shift => Mux(shift === 0.U, VecInit(0.U((1 << (log2Ceil(numBr) + 1)).W).asBools), VecInit((LowerMask(1.U << (shift-1.U))).asBools)))
  // TODO end
  val afhob_dup = redirect_dup.map(_.cfiUpdate.afhob)
  val lastBrNumOH_dup = redirect_dup.map(_.cfiUpdate.lastBrNumOH)


  val isBr_dup = redirect_dup.map(_.cfiUpdate.pd.isBr)
  val taken_dup = redirect_dup.map(_.cfiUpdate.taken)
  val real_br_taken_mask_dup =
    for (((shift, taken), addIntoHist) <- shift_dup zip taken_dup zip addIntoHist_dup)
      yield (0 until numBr).map(i => shift === (i+1).U && taken && addIntoHist )

  val oldPtr_dup = redirect_dup.map(_.cfiUpdate.histPtr)
  val updated_ptr_dup = oldPtr_dup.zip(shift_dup).map {case (oldPtr, shift) => oldPtr - shift}
  def computeFoldedHist(hist: UInt, compLen: Int)(histLen: Int): UInt = {
    if (histLen > 0) {
      val nChunks     = (histLen + compLen - 1) / compLen
      val hist_chunks = (0 until nChunks) map { i =>
        hist(min((i + 1) * compLen, histLen) - 1, i * compLen)
      }
      ParallelXOR(hist_chunks)
    }
    else 0.U
  }

  val oldFh_dup = dup_seq(WireInit(0.U.asTypeOf(new AllFoldedHistories(foldedGHistInfos))))
  oldFh_dup.zip(oldPtr_dup).map { case (oldFh, oldPtr) =>
      foldedGHistInfos.foreach { case (histLen, compLen) =>
        oldFh.getHistWithInfo((histLen, compLen)).folded_hist := computeFoldedHist(getHist(oldPtr), compLen)(histLen)
      }
  }

  val updated_fh_dup =
    for (((((oldFh, oldPtr), taken), addIntoHist), shift) <-
      oldFh_dup zip oldPtr_dup zip taken_dup zip addIntoHist_dup zip shift_dup)
    yield VecInit((0 to numBr).map(i => oldFh.update(ghv, oldPtr, i, taken && addIntoHist)))(shift)
  val thisBrNumOH_dup = shift_dup.map(shift => UIntToOH(shift, numBr+1))
  val thisAheadFhOb_dup = dup_wire(new AllAheadFoldedHistoryOldestBits(foldedGHistInfos))
  thisAheadFhOb_dup.zip(oldPtr_dup).map {case (afhob, oldPtr) => afhob.read(ghv, oldPtr)}
  val redirect_ghv_wens = (0 until HistoryLength).map(n =>
    (0 until numBr).map(b => oldPtr_dup(0).value === (CGHPtr(false.B, n.U) + b.U).value && shouldShiftVec_dup(0)(b) && do_redirect_dup(0).valid))
  val redirect_ghv_wdatas = (0 until HistoryLength).map(n =>
    Mux1H(
      (0 until numBr).map(b => oldPtr_dup(0).value === (CGHPtr(false.B, n.U) + b.U).value && shouldShiftVec_dup(0)(b)),
      real_br_taken_mask_dup(0)
    )
  )

  if (EnableGHistDiff) {
    val updated_ghist = WireInit(getHist(updated_ptr_dup(0)).asTypeOf(Vec(HistoryLength, Bool())))
    for (i <- 0 until numBr) {
      when (shift_dup(0) >= (i+1).U) {
        updated_ghist(i) := taken_dup(0) && addIntoHist_dup(0) && (i==0).B
      }
    }
    when(do_redirect_dup(0).valid) {
      s0_ghist := updated_ghist.asUInt
    }
  }

  // Commit time history checker
  if (EnableCommitGHistDiff) {
    val commitGHist = RegInit(0.U.asTypeOf(Vec(HistoryLength, Bool())))
    val commitGHistPtr = RegInit(0.U.asTypeOf(new CGHPtr))
    def getCommitHist(ptr: CGHPtr): UInt =
      (Cat(commitGHist.asUInt, commitGHist.asUInt) >> (ptr.value+1.U))(HistoryLength-1, 0)

    val updateValid        : Bool      = io.ftq_to_bpu.update.valid
    val branchValidMask    : UInt      = io.ftq_to_bpu.update.bits.ftb_entry.brValids.asUInt
    val branchCommittedMask: Vec[Bool] = io.ftq_to_bpu.update.bits.br_committed
    val misPredictMask     : UInt      = io.ftq_to_bpu.update.bits.mispred_mask.asUInt
    val takenMask          : UInt      =
      io.ftq_to_bpu.update.bits.br_taken_mask.asUInt |
        io.ftq_to_bpu.update.bits.ftb_entry.always_taken.asUInt // Always taken branch is recorded in history
    val takenIdx       : UInt = (PriorityEncoder(takenMask) + 1.U((log2Ceil(numBr)+1).W)).asUInt
    val misPredictIdx  : UInt = (PriorityEncoder(misPredictMask) + 1.U((log2Ceil(numBr)+1).W)).asUInt
    val shouldShiftMask: UInt = Mux(takenMask.orR,
        LowerMask(takenIdx).asUInt,
        ((1 << numBr) - 1).asUInt) &
      Mux(misPredictMask.orR,
        LowerMask(misPredictIdx).asUInt,
        ((1 << numBr) - 1).asUInt) &
      branchCommittedMask.asUInt
    val updateShift    : UInt   =
      Mux(updateValid && branchValidMask.orR, PopCount(branchValidMask & shouldShiftMask), 0.U)

    // Maintain the commitGHist
    for (i <- 0 until numBr) {
      when(updateShift >= (i + 1).U) {
        val ptr: CGHPtr = commitGHistPtr - i.asUInt
        commitGHist(ptr.value) := takenMask(i)
      }
    }
    when(updateValid) {
      commitGHistPtr := commitGHistPtr - updateShift
    }

    // Calculate true history using Parallel XOR
    // Do differential
    TageTableInfos.map {
      case (nRows, histLen, _) => {
        val nRowsPerBr = nRows / numBr
        val predictGHistPtr = io.ftq_to_bpu.update.bits.spec_info.histPtr
        val commitTrueHist: UInt = computeFoldedHist(getCommitHist(commitGHistPtr), log2Ceil(nRowsPerBr))(histLen)
        val predictFHist  : UInt = computeFoldedHist(getHist(predictGHistPtr), log2Ceil(nRowsPerBr))(histLen)
        XSWarn(updateValid && predictFHist =/= commitTrueHist,
          p"predict time ghist: ${predictFHist} is different from commit time: ${commitTrueHist}\n")
      }
    }
  }


  // val updatedGh = oldGh.update(shift, taken && addIntoHist)
  for ((npcGen, do_redirect) <- npcGen_dup zip do_redirect_dup)
    npcGen.register(do_redirect.valid, do_redirect.bits.cfiUpdate.target, Some("redirect_target"), 2)
  for (((foldedGhGen, do_redirect), updated_fh) <- foldedGhGen_dup zip do_redirect_dup zip updated_fh_dup)
    foldedGhGen.register(do_redirect.valid, updated_fh, Some("redirect_FGHT"), 2)
  for (((ghistPtrGen, do_redirect), updated_ptr) <- ghistPtrGen_dup zip do_redirect_dup zip updated_ptr_dup)
    ghistPtrGen.register(do_redirect.valid, updated_ptr, Some("redirect_GHPtr"), 2)
  for (((lastBrNumOHGen, do_redirect), thisBrNumOH) <- lastBrNumOHGen_dup zip do_redirect_dup zip thisBrNumOH_dup)
    lastBrNumOHGen.register(do_redirect.valid, thisBrNumOH, Some("redirect_BrNumOH"), 2)
  for (((aheadFhObGen, do_redirect), thisAheadFhOb) <- aheadFhObGen_dup zip do_redirect_dup zip thisAheadFhOb_dup)
    aheadFhObGen.register(do_redirect.valid, thisAheadFhOb, Some("redirect_AFHOB"), 2)
  ghvBitWriteGens.zip(redirect_ghv_wens).zipWithIndex.map{case ((b, w), i) =>
    b.register(w.reduce(_||_), redirect_ghv_wdatas(i), Some(s"redirect_new_bit_$i"), 2)
  }
  // no need to assign s0_last_pred

  // val need_reset = RegNext(reset.asBool) && !reset.asBool

  // Reset
  // npcGen.register(need_reset, resetVector.U, Some("reset_pc"), 1)
  // foldedGhGen.register(need_reset, 0.U.asTypeOf(s0_folded_gh), Some("reset_FGH"), 1)
  // ghistPtrGen.register(need_reset, 0.U.asTypeOf(new CGHPtr), Some("reset_GHPtr"), 1)

  s0_pc_dup.zip(npcGen_dup).map {case (s0_pc, npcGen) => s0_pc := npcGen()}
  s0_folded_gh_dup.zip(foldedGhGen_dup).map {case (s0_folded_gh, foldedGhGen) => s0_folded_gh := foldedGhGen()}
  s0_ghist_ptr_dup.zip(ghistPtrGen_dup).map {case (s0_ghist_ptr, ghistPtrGen) => s0_ghist_ptr := ghistPtrGen()}
  s0_ahead_fh_oldest_bits_dup.zip(aheadFhObGen_dup).map {case (s0_ahead_fh_oldest_bits, aheadFhObGen) =>
    s0_ahead_fh_oldest_bits := aheadFhObGen()}
  s0_last_br_num_oh_dup.zip(lastBrNumOHGen_dup).map {case (s0_last_br_num_oh, lastBrNumOHGen) =>
    s0_last_br_num_oh := lastBrNumOHGen()}
  (ghv_write_datas zip ghvBitWriteGens).map{case (wd, d) => wd := d()}
  for (i <- 0 until HistoryLength) {
    ghv_wens(i) := Seq(s1_ghv_wens, s2_ghv_wens, s3_ghv_wens, redirect_ghv_wens).map(_(i).reduce(_||_)).reduce(_||_)
    when (ghv_wens(i)) {
      ghv(i) := ghv_write_datas(i)
    }
  }

  // TODO: signals for memVio and other Redirects
  controlRedirectBubble := do_redirect_dup(0).valid && do_redirect_dup(0).bits.ControlRedirectBubble
  ControlBTBMissBubble := do_redirect_dup(0).bits.ControlBTBMissBubble
  TAGEMissBubble := do_redirect_dup(0).bits.TAGEMissBubble
  SCMissBubble := do_redirect_dup(0).bits.SCMissBubble
  ITTAGEMissBubble := do_redirect_dup(0).bits.ITTAGEMissBubble
  RASMissBubble := do_redirect_dup(0).bits.RASMissBubble

  memVioRedirectBubble := do_redirect_dup(0).valid && do_redirect_dup(0).bits.MemVioRedirectBubble
  otherRedirectBubble := do_redirect_dup(0).valid && do_redirect_dup(0).bits.OtherRedirectBubble
  btbMissBubble := do_redirect_dup(0).valid && do_redirect_dup(0).bits.BTBMissBubble
  overrideBubble(0) := s2_redirect_dup(0)
  overrideBubble(1) := s3_redirect_dup(0)
  ftqUpdateBubble(0) := !s1_components_ready_dup(0)
  ftqUpdateBubble(1) := !s2_components_ready_dup(0)
  ftqUpdateBubble(2) := !s3_components_ready_dup(0)
  ftqFullStall := !io.bpu_to_ftq.resp.ready
  io.bpu_to_ftq.resp.bits.topdown_info := topdown_stages(numOfStage - 1)

  // topdown handling logic here
  when (controlRedirectBubble) {
    /*
    for (i <- 0 until numOfStage)
      topdown_stages(i).reasons(TopDownCounters.ControlRedirectBubble.id) := true.B
    io.bpu_to_ftq.resp.bits.topdown_info.reasons(TopDownCounters.ControlRedirectBubble.id) := true.B
    */
    when (ControlBTBMissBubble) {
      for (i <- 0 until numOfStage)
        topdown_stages(i).reasons(TopDownCounters.BTBMissBubble.id) := true.B
      io.bpu_to_ftq.resp.bits.topdown_info.reasons(TopDownCounters.BTBMissBubble.id) := true.B
    } .elsewhen (TAGEMissBubble) {
      for (i <- 0 until numOfStage)
        topdown_stages(i).reasons(TopDownCounters.TAGEMissBubble.id) := true.B
      io.bpu_to_ftq.resp.bits.topdown_info.reasons(TopDownCounters.TAGEMissBubble.id) := true.B
    } .elsewhen (SCMissBubble) {
      for (i <- 0 until numOfStage)
        topdown_stages(i).reasons(TopDownCounters.SCMissBubble.id) := true.B
      io.bpu_to_ftq.resp.bits.topdown_info.reasons(TopDownCounters.SCMissBubble.id) := true.B
    } .elsewhen (ITTAGEMissBubble) {
      for (i <- 0 until numOfStage)
        topdown_stages(i).reasons(TopDownCounters.ITTAGEMissBubble.id) := true.B
      io.bpu_to_ftq.resp.bits.topdown_info.reasons(TopDownCounters.ITTAGEMissBubble.id) := true.B
    } .elsewhen (RASMissBubble) {
      for (i <- 0 until numOfStage)
        topdown_stages(i).reasons(TopDownCounters.RASMissBubble.id) := true.B
      io.bpu_to_ftq.resp.bits.topdown_info.reasons(TopDownCounters.RASMissBubble.id) := true.B
    }
  }
  when (memVioRedirectBubble) {
    for (i <- 0 until numOfStage)
      topdown_stages(i).reasons(TopDownCounters.MemVioRedirectBubble.id) := true.B
    io.bpu_to_ftq.resp.bits.topdown_info.reasons(TopDownCounters.MemVioRedirectBubble.id) := true.B
  }
  when (otherRedirectBubble) {
    for (i <- 0 until numOfStage)
      topdown_stages(i).reasons(TopDownCounters.OtherRedirectBubble.id) := true.B
    io.bpu_to_ftq.resp.bits.topdown_info.reasons(TopDownCounters.OtherRedirectBubble.id) := true.B
  }
  when (btbMissBubble) {
    for (i <- 0 until numOfStage)
      topdown_stages(i).reasons(TopDownCounters.BTBMissBubble.id) := true.B
    io.bpu_to_ftq.resp.bits.topdown_info.reasons(TopDownCounters.BTBMissBubble.id) := true.B
  }

  for (i <- 0 until numOfStage) {
    if (i < numOfStage - overrideStage) {
      when (overrideBubble(i)) {
        for (j <- 0 to i)
          topdown_stages(j).reasons(TopDownCounters.OverrideBubble.id) := true.B
      }
    }
    if (i < numOfStage - ftqUpdateStage) {
      when (ftqUpdateBubble(i)) {
        topdown_stages(i).reasons(TopDownCounters.FtqUpdateBubble.id) := true.B
      }
    }
  }
  when (ftqFullStall) {
    topdown_stages(0).reasons(TopDownCounters.FtqFullStall.id) := true.B
  }

  XSError(isBefore(redirect_dup(0).cfiUpdate.histPtr, s3_ghist_ptr_dup(0)) && do_redirect_dup(0).valid,
    p"s3_ghist_ptr ${s3_ghist_ptr_dup(0)} exceeds redirect histPtr ${redirect_dup(0).cfiUpdate.histPtr}\n")
  XSError(isBefore(redirect_dup(0).cfiUpdate.histPtr, s2_ghist_ptr_dup(0)) && do_redirect_dup(0).valid,
    p"s2_ghist_ptr ${s2_ghist_ptr_dup(0)} exceeds redirect histPtr ${redirect_dup(0).cfiUpdate.histPtr}\n")
  XSError(isBefore(redirect_dup(0).cfiUpdate.histPtr, s1_ghist_ptr_dup(0)) && do_redirect_dup(0).valid,
    p"s1_ghist_ptr ${s1_ghist_ptr_dup(0)} exceeds redirect histPtr ${redirect_dup(0).cfiUpdate.histPtr}\n")

  XSDebug(RegNext(reset.asBool) && !reset.asBool, "Reseting...\n")
  XSDebug(io.ftq_to_bpu.update.valid, p"Update from ftq\n")
  XSDebug(io.ftq_to_bpu.redirect.valid, p"Redirect from ftq\n")

  XSDebug("[BP0]                 fire=%d                      pc=%x\n", s0_fire_dup(0), s0_pc_dup(0))
  XSDebug("[BP1] v=%d r=%d cr=%d fire=%d             flush=%d pc=%x\n",
    s1_valid_dup(0), s1_ready_dup(0), s1_components_ready_dup(0), s1_fire_dup(0), s1_flush_dup(0), s1_pc)
  XSDebug("[BP2] v=%d r=%d cr=%d fire=%d redirect=%d flush=%d pc=%x\n",
    s2_valid_dup(0), s2_ready_dup(0), s2_components_ready_dup(0), s2_fire_dup(0), s2_redirect_dup(0), s2_flush_dup(0), s2_pc)
  XSDebug("[BP3] v=%d r=%d cr=%d fire=%d redirect=%d flush=%d pc=%x\n",
    s3_valid_dup(0), s3_ready_dup(0), s3_components_ready_dup(0), s3_fire_dup(0), s3_redirect_dup(0), s3_flush_dup(0), s3_pc)
  XSDebug("[FTQ] ready=%d\n", io.bpu_to_ftq.resp.ready)
  XSDebug("resp.s1.target=%x\n", resp.s1.getTarget(0))
  XSDebug("resp.s2.target=%x\n", resp.s2.getTarget(0))
  // XSDebug("s0_ghist: %b\n", s0_ghist.predHist)
  // XSDebug("s1_ghist: %b\n", s1_ghist.predHist)
  // XSDebug("s2_ghist: %b\n", s2_ghist.predHist)
  // XSDebug("s2_predicted_ghist: %b\n", s2_predicted_ghist.predHist)
  XSDebug(p"s0_ghist_ptr: ${s0_ghist_ptr_dup(0)}\n")
  XSDebug(p"s1_ghist_ptr: ${s1_ghist_ptr_dup(0)}\n")
  XSDebug(p"s2_ghist_ptr: ${s2_ghist_ptr_dup(0)}\n")
  XSDebug(p"s3_ghist_ptr: ${s3_ghist_ptr_dup(0)}\n")

  io.ftq_to_bpu.update.bits.display(io.ftq_to_bpu.update.valid)
  io.ftq_to_bpu.redirect.bits.display(io.ftq_to_bpu.redirect.valid)


  XSPerfAccumulate("s2_redirect", s2_redirect_dup(0))
  XSPerfAccumulate("s3_redirect", s3_redirect_dup(0))
  XSPerfAccumulate("s1_not_valid", !s1_valid_dup(0))

  val perfEvents = predictors.asInstanceOf[Composer].getPerfEvents
  generatePerfEvent()
}