refactor(Frontend): replace NamedUInt with EnumUInt (#4529)

Use EnumUInt introduced by #4528 to do some compile-time check.

Also:
- add `class ExceptionType` to replace `ExceptionType.hasException(xxx)`
with `xxx.hasException`, etc.
- apply CamelCase to `BrType`.

src/main/scala/xiangshan/backend/decode/isa/predecode/predecode.scala

@@ -33,12 +33,12 @@ object PreDecodeInst {
 
   val brTable = Array(
     // C_JAL     -> List(BrType.jal),
-    C_EBREAK  -> List(BrType.notCFI), // c.ebreak should not be decoded as jalr, higher priority than c.jalr
-    C_J       -> List(BrType.jal),
-    C_JALR    -> List(BrType.jalr),
-    C_BRANCH  -> List(BrType.branch),
-    JAL       -> List(BrType.jal),
-    JALR      -> List(BrType.jalr),
-    BRANCH    -> List(BrType.branch)
+    C_EBREAK  -> List(BrType.NotCfi), // c.ebreak should not be decoded as jalr, higher priority than c.jalr
+    C_J       -> List(BrType.Jal),
+    C_JALR    -> List(BrType.Jalr),
+    C_BRANCH  -> List(BrType.Branch),
+    JAL       -> List(BrType.Jal),
+    JALR      -> List(BrType.Jalr),
+    BRANCH    -> List(BrType.Branch)
   )
 }

src/main/scala/xiangshan/backend/trace/Interface.scala

@@ -82,9 +82,9 @@ object Itype extends NamedUInt(4) {
   def jumpTypeGen(brType: UInt, rd: OpRegType, rs: OpRegType): UInt = {
 
     val isEqualRdRs = rd === rs
-    val isJal       = brType === BrType.jal
-    val isJalr      = brType === BrType.jalr
-    val isBranch    = brType === BrType.branch
+    val isJal       = brType === BrType.Jal
+    val isJalr      = brType === BrType.Jalr
+    val isBranch    = brType === BrType.Branch
 
     // push to RAS when rd is link, pop from RAS when rs is link
     def isUninferableCall      = isJalr && rd.isLink && (!rs.isLink || rs.isLink && isEqualRdRs)  //8   push

src/main/scala/xiangshan/frontend/FrontendBundle.scala

@@ -24,7 +24,7 @@ import ftq.FtqRedirectSramEntry
 import ftq.FtqRfComponents
 import org.chipsalliance.cde.config.Parameters
 import utility._
-import utils.NamedUInt
+import utils.EnumUInt
 import xiangshan._
 import xiangshan.backend.GPAMemEntry
 import xiangshan.backend.fu.PMPRespBundle
@@ -88,7 +88,7 @@ class FtqICacheInfo(implicit p: Parameters) extends XSBundle with HasICacheParam
 
 class FtqToPrefetchBundle(implicit p: Parameters) extends XSBundle {
   val req:              FtqICacheInfo = new FtqICacheInfo
-  val backendException: UInt          = ExceptionType()
+  val backendException: ExceptionType = new ExceptionType
 }
 
 class FtqToFetchBundle(implicit p: Parameters) extends XSBundle with HasICacheParameters {
@@ -152,138 +152,94 @@ class mmioCommitRead(implicit p: Parameters) extends XSBundle {
   val mmioLastCommit = Input(Bool())
 }
 
-object ExceptionType extends NamedUInt(2) {
-  def none: UInt = "b00".U(width.W)
-  def pf:   UInt = "b01".U(width.W) // instruction page fault
-  def gpf:  UInt = "b10".U(width.W) // instruction guest page fault
-  def af:   UInt = "b11".U(width.W) // instruction access fault
+class ExceptionType extends Bundle {
+  val value: UInt = ExceptionType.Value()
 
-  def hasException(e: UInt):             Bool = e =/= none
-  def hasException(e: Vec[UInt]):        Bool = e.map(_ =/= none).reduce(_ || _)
-  def hasException(e: IndexedSeq[UInt]): Bool = hasException(VecInit(e))
+  def isNone: Bool = value === ExceptionType.Value.None
+  def isPf:   Bool = value === ExceptionType.Value.Pf
+  def isGpf:  Bool = value === ExceptionType.Value.Gpf
+  def isAf:   Bool = value === ExceptionType.Value.Af
 
-  def fromOH(has_pf: Bool, has_gpf: Bool, has_af: Bool): UInt = {
+  def hasException: Bool = value =/= ExceptionType.Value.None
+
+  /** merge exception from multiple sources, the leftmost one has higher priority
+   * @example {{{
+   *   val itlbException = ExceptionType(io.itlb.resp.bits)
+   *   val pmpException = ExceptionType(io.pmp.resp)
+   *
+   *   // itlb has higher priority than pmp, as when itlb has exception, pAddr is not valid
+   *   val exception = itlbException || pmpException
+   * }}}
+   */
+  def ||(that: ExceptionType): ExceptionType =
+    Mux(this.hasException, this, that)
+}
+
+object ExceptionType {
+  private object Value extends EnumUInt(4) {
+    def None: UInt = 0.U(width.W)
+    def Pf:   UInt = 1.U(width.W) // instruction page fault
+    def Gpf:  UInt = 2.U(width.W) // instruction guest page fault
+    def Af:   UInt = 3.U(width.W) // instruction access fault
+  }
+
+  def apply(that: UInt): ExceptionType = {
+    Value.assertLegal(that)
+    val e = Wire(new ExceptionType)
+    e.value := that
+    e
+  }
+
+  def None: ExceptionType = apply(Value.None)
+  def Pf:   ExceptionType = apply(Value.Pf)
+  def Gpf:  ExceptionType = apply(Value.Gpf)
+  def Af:   ExceptionType = apply(Value.Af)
+
+  def apply(hasPf: Bool, hasGpf: Bool, hasAf: Bool): ExceptionType = {
     assert(
-      PopCount(VecInit(has_pf, has_gpf, has_af)) <= 1.U,
-      "ExceptionType.fromOH receives input that is not one-hot: pf=%d, gpf=%d, af=%d",
-      has_pf,
-      has_gpf,
-      has_af
+      PopCount(VecInit(hasPf, hasGpf, hasAf)) <= 1.U,
+      "ExceptionType receives input that is not one-hot: pf=%d, gpf=%d, af=%d",
+      hasPf,
+      hasGpf,
+      hasAf
     )
     // input is at-most-one-hot encoded, so we don't worry about priority here.
     MuxCase(
-      none,
+      None,
       Seq(
-        has_pf  -> pf,
-        has_gpf -> gpf,
-        has_af  -> af
+        hasPf  -> Pf,
+        hasGpf -> Gpf,
+        hasAf  -> Af
       )
     )
   }
 
+  // only af is used most frequently (pmp / ecc / tilelink), so we define a shortcut
+  // we cannot use default parameter in apply(), as it is overloaded and scala won't allow
+  def apply(hasAf: Bool): ExceptionType =
+    apply(hasPf = false.B, hasGpf = false.B, hasAf = hasAf)
+
   // raise pf/gpf/af according to itlb response
-  def fromTlbResp(resp: TlbResp, useDup: Int = 0): UInt = {
+  def fromTlbResp(resp: TlbResp, useDup: Int = 0): ExceptionType = {
     require(useDup >= 0 && useDup < resp.excp.length)
     // itlb is guaranteed to respond at most one exception
-    fromOH(
-      resp.excp(useDup).pf.instr,
-      resp.excp(useDup).gpf.instr,
-      resp.excp(useDup).af.instr
+    apply(
+      hasPf = resp.excp(useDup).pf.instr,
+      hasGpf = resp.excp(useDup).gpf.instr,
+      hasAf = resp.excp(useDup).af.instr
     )
   }
 
   // raise af if pmp check failed
-  def fromPMPResp(resp: PMPRespBundle): UInt =
-    Mux(resp.instr, af, none)
-
-  // raise af if meta/data array ecc check failed or l2 cache respond with tilelink corrupt
-  /* FIXME: RISC-V Machine ISA v1.13 (draft) introduced a "hardware error" exception, described as:
-   * > A Hardware Error exception is a synchronous exception triggered when corrupted or
-   * > uncorrectable data is accessed explicitly or implicitly by an instruction. In this context,
-   * > "data" encompasses all types of information used within a RISC-V hart. Upon a hardware
-   * > error exception, the xepc register is set to the address of the instruction that attempted to
-   * > access corrupted data, while the xtval register is set either to 0 or to the virtual address
-   * > of an instruction fetch, load, or store that attempted to access corrupted data. The priority
-   * > of Hardware Error exception is implementation-defined, but any given occurrence is
-   * > generally expected to be recognized at the point in the overall priority order at which the
-   * > hardware error is discovered.
-   * Maybe it's better to raise hardware error instead of access fault when ECC check failed.
-   * But it's draft and XiangShan backend does not implement this exception code yet, so we still raise af here.
-   */
-  def fromECC(enable: Bool, corrupt: Bool): UInt =
-    Mux(enable && corrupt, af, none)
-
-  def fromTilelink(corrupt: Bool): UInt =
-    Mux(corrupt, af, none)
-
-  /**Generates exception mux tree
-   *
-   * Exceptions that are further to the left in the parameter list have higher priority
-   * @example
-   * {{{
-   *   val itlb_exception = ExceptionType.fromTlbResp(io.itlb.resp.bits)
-   *   // so as pmp_exception, meta_corrupt
-   *   // ExceptionType.merge(itlb_exception, pmp_exception, meta_corrupt) is equivalent to:
-   *   Mux(
-   *     itlb_exception =/= none,
-   *     itlb_exception,
-   *     Mux(pmp_exception =/= none, pmp_exception, meta_corrupt)
-   *   )
-   * }}}
-   */
-  def merge(exceptions: UInt*): UInt = {
-//    // recursively generate mux tree
-//    if (exceptions.length == 1) {
-//      require(exceptions.head.getWidth == width)
-//      exceptions.head
-//    } else {
-//      Mux(exceptions.head =/= none, exceptions.head, merge(exceptions.tail: _*))
-//    }
-    // use MuxCase with default
-    exceptions.foreach(e => require(e.getWidth == width))
-    val mapping = exceptions.init.map(e => (e =/= none) -> e)
-    val default = exceptions.last
-    MuxCase(default, mapping)
-  }
-
-  /**Generates exception mux tree for multi-port exception vectors
-   *
-   * Exceptions that are further to the left in the parameter list have higher priority
-   * @example
-   * {{{
-   *   val itlb_exception = VecInit((0 until PortNumber).map(i => ExceptionType.fromTlbResp(io.itlb(i).resp.bits)))
-   *   // so as pmp_exception, meta_corrupt
-   *   // ExceptionType.merge(itlb_exception, pmp_exception, meta_corrupt) is equivalent to:
-   *   VecInit((0 until PortNumber).map(i => Mux(
-   *     itlb_exception(i) =/= none,
-   *     itlb_exception(i),
-   *     Mux(pmp_exception(i) =/= none, pmp_exception(i), meta_corrupt(i))
-   *   ))
-   * }}}
-   */
-  def merge(exceptionVecs: Vec[UInt]*): Vec[UInt] = {
-//    // recursively generate mux tree
-//    if (exceptionVecs.length == 1) {
-//      exceptionVecs.head.foreach(e => require(e.getWidth == width))
-//      exceptionVecs.head
-//    } else {
-//      require(exceptionVecs.head.length == exceptionVecs.last.length)
-//      VecInit((exceptionVecs.head zip merge(exceptionVecs.tail: _*)).map{ case (high, low) =>
-//        Mux(high =/= none, high, low)
-//      })
-//    }
-    // merge port-by-port
-    val length = exceptionVecs.head.length
-    exceptionVecs.tail.foreach(vec => require(vec.length == length))
-    VecInit((0 until length).map(i => merge(exceptionVecs.map(_(i)): _*)))
-  }
+  def fromPmpResp(resp: PMPRespBundle): ExceptionType =
+    apply(hasAf = resp.instr)
 }
 
-object BrType extends NamedUInt(2) {
-  def notCFI: UInt = "b00".U(width.W)
-  def branch: UInt = "b01".U(width.W)
-  def jal:    UInt = "b10".U(width.W)
-  def jalr:   UInt = "b11".U(width.W)
+object BrType extends EnumUInt(4) {
+  def NotCfi: UInt = 0.U(width.W)
+  def Branch: UInt = 1.U(width.W)
+  def Jal:    UInt = 2.U(width.W)
+  def Jalr:   UInt = 3.U(width.W)
 }
 
 class PreDecodeInfo extends Bundle { // 8 bit
@@ -293,10 +249,10 @@ class PreDecodeInfo extends Bundle { // 8 bit
   val isCall = Bool()
   val isRet  = Bool()
   // val excType = UInt(3.W)
-  def isBr   = brType === BrType.branch
-  def isJal  = brType === BrType.jal
-  def isJalr = brType === BrType.jalr
-  def notCFI = brType === BrType.notCFI
+  def isBr   = brType === BrType.Branch
+  def isJal  = brType === BrType.Jal
+  def isJalr = brType === BrType.Jalr
+  def notCFI = brType === BrType.NotCfi
 }
 
 class FetchToIBuffer(implicit p: Parameters) extends XSBundle {
@@ -307,7 +263,7 @@ class FetchToIBuffer(implicit p: Parameters) extends XSBundle {
   val foldpc           = Vec(PredictWidth, UInt(MemPredPCWidth.W))
   val ftqOffset        = Vec(PredictWidth, ValidUndirectioned(UInt(log2Ceil(PredictWidth).W)))
   val backendException = Vec(PredictWidth, Bool())
-  val exceptionType    = Vec(PredictWidth, ExceptionType())
+  val exceptionType    = Vec(PredictWidth, new ExceptionType)
   val crossPageIPFFix  = Vec(PredictWidth, Bool())
   val illegalInstr     = Vec(PredictWidth, Bool())
   val triggered        = Vec(PredictWidth, TriggerAction())

src/main/scala/xiangshan/frontend/IBuffer.scala

@@ -49,6 +49,41 @@ class IBufferIO(implicit p: Parameters) extends XSBundle {
   val stallReason          = new StallReasonIO(DecodeWidth)
 }
 
+object IBufferExceptionType extends EnumUInt(8) {
+  def None:        UInt = "b000".U(width.W)
+  def NonCrossPF:  UInt = "b001".U(width.W)
+  def NonCrossGPF: UInt = "b010".U(width.W)
+  def NonCrossAF:  UInt = "b011".U(width.W)
+  def RvcII:       UInt = "b100".U(width.W) // illegal instruction
+  def CrossPF:     UInt = "b101".U(width.W)
+  def CrossGPF:    UInt = "b110".U(width.W)
+  def CrossAF:     UInt = "b111".U(width.W)
+
+  def cvtFromFetchExcpAndCrossPageAndRVCII(fetchExcp: ExceptionType, crossPage: Bool, rvcIll: Bool): UInt =
+    MuxCase(
+      0.U,
+      Seq(
+        crossPage              -> Cat(1.U(1.W), fetchExcp.value),
+        fetchExcp.hasException -> fetchExcp.value,
+        rvcIll                 -> this.RvcII
+      )
+    )
+
+  def isRVCII(uint: UInt): Bool = {
+    this.checkInputWidth(uint)
+    uint(2) && uint(1, 0) === 0.U
+  }
+
+  def isCrossPage(uint: UInt): Bool = {
+    this.checkInputWidth(uint)
+    uint(2) && uint(1, 0) =/= 0.U
+  }
+
+  def isPF(uint:  UInt): Bool = uint(1, 0) === this.NonCrossPF(1, 0)
+  def isGPF(uint: UInt): Bool = uint(1, 0) === this.NonCrossGPF(1, 0)
+  def isAF(uint:  UInt): Bool = uint(1, 0) === this.NonCrossAF(1, 0)
+}
+
 class IBufEntry(implicit p: Parameters) extends XSBundle {
   val inst             = UInt(32.W)
   val pc               = PrunedAddr(VAddrBits)
@@ -109,48 +144,6 @@ class IBufEntry(implicit p: Parameters) extends XSBundle {
     cf.debug_seqNum                      := debug_seqNum
     cf
   }
-
-  object IBufferExceptionType extends NamedUInt(3) {
-    def None        = "b000".U
-    def NonCrossPF  = "b001".U
-    def NonCrossGPF = "b010".U
-    def NonCrossAF  = "b011".U
-    // illegal instruction
-    def rvcII    = "b100".U
-    def CrossPF  = "b101".U
-    def CrossGPF = "b110".U
-    def CrossAF  = "b111".U
-
-    def cvtFromFetchExcpAndCrossPageAndRVCII(fetchExcp: UInt, crossPage: Bool, rvcIll: Bool): UInt = {
-      require(
-        fetchExcp.getWidth == ExceptionType.width,
-        s"The width(${fetchExcp.getWidth}) of fetchExcp should be equal to " +
-          s"the width(${ExceptionType.width}) of frontend.ExceptionType."
-      )
-      MuxCase(
-        0.U,
-        Seq(
-          crossPage     -> Cat(1.U(1.W), fetchExcp),
-          fetchExcp.orR -> fetchExcp,
-          rvcIll        -> this.rvcII
-        )
-      )
-    }
-
-    def isRVCII(uint: UInt): Bool = {
-      this.checkInputWidth(uint)
-      uint(2) && uint(1, 0) === 0.U
-    }
-
-    def isCrossPage(uint: UInt): Bool = {
-      this.checkInputWidth(uint)
-      uint(2) && uint(1, 0) =/= 0.U
-    }
-
-    def isPF(uint:  UInt): Bool = uint(1, 0) === this.NonCrossPF(1, 0)
-    def isGPF(uint: UInt): Bool = uint(1, 0) === this.NonCrossGPF(1, 0)
-    def isAF(uint:  UInt): Bool = uint(1, 0) === this.NonCrossAF(1, 0)
-  }
 }
 
 class IBuffer(implicit p: Parameters) extends XSModule with HasCircularQueuePtrHelper with HasPerfEvents {

src/main/scala/xiangshan/frontend/ftq/Ftq.scala

@@ -159,13 +159,13 @@ class Ftq(implicit p: Parameters) extends FtqModule
   // raises IPF or IAF, which is ifuWbPtr_write or IfuPtr_write.
   // Only when IFU has written back that FTQ entry can backendIpf and backendIaf be false because this
   // makes sure that IAF and IPF are correctly raised instead of being flushed by redirect requests.
-  val backendException  = RegInit(ExceptionType.none)
+  val backendException  = RegInit(ExceptionType.None)
   val backendPcFaultPtr = RegInit(FtqPtr(false.B, 0.U))
   when(fromBackendRedirect.valid) {
-    backendException := ExceptionType.fromOH(
-      has_pf = fromBackendRedirect.bits.cfiUpdate.backendIPF,
-      has_gpf = fromBackendRedirect.bits.cfiUpdate.backendIGPF,
-      has_af = fromBackendRedirect.bits.cfiUpdate.backendIAF
+    backendException := ExceptionType(
+      hasPf = fromBackendRedirect.bits.cfiUpdate.backendIPF,
+      hasGpf = fromBackendRedirect.bits.cfiUpdate.backendIGPF,
+      hasAf = fromBackendRedirect.bits.cfiUpdate.backendIAF
     )
     when(
       fromBackendRedirect.bits.cfiUpdate.backendIPF || fromBackendRedirect.bits.cfiUpdate.backendIGPF ||
@@ -174,7 +174,7 @@ class Ftq(implicit p: Parameters) extends FtqModule
       backendPcFaultPtr := ifuWbPtr_write
     }
   }.elsewhen(ifuWbPtr =/= backendPcFaultPtr) {
-    backendException := ExceptionType.none
+    backendException := ExceptionType.None
   }
 
   // **********************************************************************
@@ -473,7 +473,7 @@ class Ftq(implicit p: Parameters) extends FtqModule
     copy.ftqIdx := ifuPtr
   }
   io.toICache.fetchReq.bits.isBackendException :=
-    ExceptionType.hasException(backendException) && backendPcFaultPtr === ifuPtr
+    backendException.hasException && backendPcFaultPtr === ifuPtr
 
   io.toICache.prefetchReq.valid := toPrefetchEntryToSend && pfPtr =/= bpuPtr
   io.toICache.prefetchReq.bits.req.fromFtqPcBundle(toPrefetchPcBundle)
@@ -481,7 +481,7 @@ class Ftq(implicit p: Parameters) extends FtqModule
   io.toICache.prefetchReq.bits.backendException := Mux(
     backendPcFaultPtr === pfPtr,
     backendException,
-    ExceptionType.none
+    ExceptionType.None
   )
   // io.toICache.fetchReq.bits.bypassSelect := last_cycle_bpu_in && bpu_in_bypass_ptr === ifuPtr
   // io.toICache.fetchReq.bits.bpuBypassWrite.zipWithIndex.map{case(bypassWrtie, i) =>

src/main/scala/xiangshan/frontend/icache/Bundles.scala

@@ -161,14 +161,14 @@ class ReplacerVictimBundle(implicit p: Parameters) extends ICacheBundle {
 /* ***** MainPipe ***** */
 // ICache(MainPipe) -> IFU
 class ICacheRespBundle(implicit p: Parameters) extends ICacheBundle {
-  val doubleline:         Bool            = Bool()
-  val vAddr:              Vec[PrunedAddr] = Vec(PortNumber, PrunedAddr(VAddrBits))
-  val data:               UInt            = UInt(blockBits.W)
-  val pAddr:              Vec[PrunedAddr] = Vec(PortNumber, PrunedAddr(PAddrBits))
-  val exception:          Vec[UInt]       = Vec(PortNumber, ExceptionType())
-  val pmpMmio:            Vec[Bool]       = Vec(PortNumber, Bool())
-  val itlbPbmt:           Vec[UInt]       = Vec(PortNumber, UInt(Pbmt.width.W))
-  val isBackendException: Bool            = Bool()
+  val doubleline:         Bool               = Bool()
+  val vAddr:              Vec[PrunedAddr]    = Vec(PortNumber, PrunedAddr(VAddrBits))
+  val data:               UInt               = UInt(blockBits.W)
+  val pAddr:              Vec[PrunedAddr]    = Vec(PortNumber, PrunedAddr(PAddrBits))
+  val exception:          Vec[ExceptionType] = Vec(PortNumber, new ExceptionType)
+  val pmpMmio:            Vec[Bool]          = Vec(PortNumber, Bool())
+  val itlbPbmt:           Vec[UInt]          = Vec(PortNumber, UInt(Pbmt.width.W))
+  val isBackendException: Bool               = Bool()
   /* NOTE: GPAddrBits(=50bit) is not enough for gpAddr here, refer to PR#3795
    * Sv48*4 only allows 50bit gpAddr, when software violates this requirement
    * it needs to fill the mtval2 register with the full XLEN(=64bit) gpAddr,
@@ -181,11 +181,11 @@ class ICacheRespBundle(implicit p: Parameters) extends ICacheBundle {
 
 /* ***** PrefetchPipe ***** */
 class PrefetchReqBundle(implicit p: Parameters) extends ICacheBundle {
-  val startAddr:        PrunedAddr = PrunedAddr(VAddrBits)
-  val nextlineStart:    PrunedAddr = PrunedAddr(VAddrBits)
-  val ftqIdx:           FtqPtr     = new FtqPtr
-  val isSoftPrefetch:   Bool       = Bool()
-  val backendException: UInt       = ExceptionType()
+  val startAddr:        PrunedAddr    = PrunedAddr(VAddrBits)
+  val nextlineStart:    PrunedAddr    = PrunedAddr(VAddrBits)
+  val ftqIdx:           FtqPtr        = new FtqPtr
+  val isSoftPrefetch:   Bool          = Bool()
+  val backendException: ExceptionType = new ExceptionType
 
   def crossCacheline: Bool = startAddr(blockOffBits - 1) === 1.U
 
@@ -214,12 +214,12 @@ class PrefetchReqBundle(implicit p: Parameters) extends ICacheBundle {
  *      to save area, we separate those signals from WayLookupEntry and store only once.
  */
 class WayLookupEntry(implicit p: Parameters) extends ICacheBundle {
-  val vSetIdx:       Vec[UInt] = Vec(PortNumber, UInt(idxBits.W))
-  val waymask:       Vec[UInt] = Vec(PortNumber, UInt(nWays.W))
-  val pTag:          Vec[UInt] = Vec(PortNumber, UInt(tagBits.W))
-  val itlbException: Vec[UInt] = Vec(PortNumber, ExceptionType())
-  val itlbPbmt:      Vec[UInt] = Vec(PortNumber, UInt(Pbmt.width.W))
-  val metaCodes:     Vec[UInt] = Vec(PortNumber, UInt(ICacheMetaCodeBits.W))
+  val vSetIdx:       Vec[UInt]          = Vec(PortNumber, UInt(idxBits.W))
+  val waymask:       Vec[UInt]          = Vec(PortNumber, UInt(nWays.W))
+  val pTag:          Vec[UInt]          = Vec(PortNumber, UInt(tagBits.W))
+  val itlbException: Vec[ExceptionType] = Vec(PortNumber, new ExceptionType)
+  val itlbPbmt:      Vec[UInt]          = Vec(PortNumber, UInt(Pbmt.width.W))
+  val metaCodes:     Vec[UInt]          = Vec(PortNumber, UInt(ICacheMetaCodeBits.W))
 }
 
 class WayLookupGpfEntry(implicit p: Parameters) extends ICacheBundle {
@@ -233,14 +233,14 @@ class WayLookupBundle(implicit p: Parameters) extends ICacheBundle {
   val gpf   = new WayLookupGpfEntry
 
   // for compatibility
-  def vSetIdx:           Vec[UInt]  = entry.vSetIdx
-  def waymask:           Vec[UInt]  = entry.waymask
-  def pTag:              Vec[UInt]  = entry.pTag
-  def itlbException:     Vec[UInt]  = entry.itlbException
-  def itlbPbmt:          Vec[UInt]  = entry.itlbPbmt
-  def metaCodes:         Vec[UInt]  = entry.metaCodes
-  def gpAddr:            PrunedAddr = gpf.gpAddr
-  def isForVSnonLeafPTE: Bool       = gpf.isForVSnonLeafPTE
+  def vSetIdx:           Vec[UInt]          = entry.vSetIdx
+  def waymask:           Vec[UInt]          = entry.waymask
+  def pTag:              Vec[UInt]          = entry.pTag
+  def itlbException:     Vec[ExceptionType] = entry.itlbException
+  def itlbPbmt:          Vec[UInt]          = entry.itlbPbmt
+  def metaCodes:         Vec[UInt]          = entry.metaCodes
+  def gpAddr:            PrunedAddr         = gpf.gpAddr
+  def isForVSnonLeafPTE: Bool               = gpf.isForVSnonLeafPTE
 }
 
 /* ***** Miss ***** */

src/main/scala/xiangshan/frontend/icache/ICacheCtrlUnit.scala

@@ -27,7 +27,7 @@ import freechips.rocketchip.regmapper.RegReadFn
 import freechips.rocketchip.regmapper.RegWriteFn
 import freechips.rocketchip.tilelink.TLRegisterNode
 import org.chipsalliance.cde.config.Parameters
-import utils.NamedUInt
+import utils.EnumUInt
 import xiangshan.frontend.PrunedAddrInit
 
 // currently for ECC control only
@@ -61,7 +61,7 @@ class ICacheCtrlUnit(params: ICacheCtrlUnitParameters)(implicit p: Parameters) e
 
     // eccCtrl.ierror: inject error code
     private def nInjError: Int = 8
-    private object EccCtrlInjError extends NamedUInt(log2Up(nInjError)) {
+    private object EccCtrlInjError extends EnumUInt(nInjError) {
       def NotEnabled:    UInt = 0.U(width.W) // try to inject when ECC check is not enabled
       def TargetInvalid: UInt = 1.U(width.W) // try to inject to invalid(rsvd) eccCtrl.itarget
       def NotFound:      UInt = 2.U(width.W) // try to inject to eccIAddr.pAddr does not exist in ICache
@@ -78,7 +78,7 @@ class ICacheCtrlUnit(params: ICacheCtrlUnitParameters)(implicit p: Parameters) e
     }
     // eccCtrl.istatus: inject status
     private def nInjStatus: Int = 8
-    private object EccCtrlInjStatus extends NamedUInt(log2Up(nInjStatus)) {
+    private object EccCtrlInjStatus extends EnumUInt(nInjStatus) {
       def Idle:     UInt = 0.U(width.W)
       def Working:  UInt = 1.U(width.W)
       def Injected: UInt = 2.U(width.W)
@@ -94,7 +94,7 @@ class ICacheCtrlUnit(params: ICacheCtrlUnitParameters)(implicit p: Parameters) e
     }
     // eccCtrl.itarget: inject target
     private def nInjTarget: Int = 4
-    private object EccCtrlInjTarget extends NamedUInt(log2Up(nInjTarget)) {
+    private object EccCtrlInjTarget extends EnumUInt(nInjTarget) {
       def MetaArray: UInt = 0.U(width.W)
       def DataArray: UInt = 2.U(width.W)
       @unused
@@ -151,7 +151,7 @@ class ICacheCtrlUnit(params: ICacheCtrlUnitParameters)(implicit p: Parameters) e
 
     // inject FSM
     private def nInjectFsmState: Int = 5
-    private object InjectFsmState extends NamedUInt(log2Up(nInjectFsmState)) {
+    private object InjectFsmState extends EnumUInt(nInjectFsmState) {
       // scala ask identifier that begins with uppercase cannot be used in pattern matching like `X :: Nil = Enum()`
       // but we want UpperCamelCase for constants for better readability, so we dont use Enum() here
       def Idle:         UInt = 0.U(width.W)

src/main/scala/xiangshan/frontend/icache/ICacheMainPipe.scala

@@ -224,14 +224,11 @@ class ICacheMainPipe(implicit p: Parameters) extends ICacheModule
     p.bits.size := 3.U
     p.bits.cmd  := TlbCmd.exec
   }
-  private val s1_pmpException = VecInit(fromPmp.map(ExceptionType.fromPMPResp))
+  private val s1_pmpException = VecInit(fromPmp.map(ExceptionType.fromPmpResp))
   private val s1_pmpMmio      = VecInit(fromPmp.map(_.mmio))
 
   // merge s1 itlb/pmp exceptions, itlb has the highest priority, pmp next
-  private val s1_exceptionOut = ExceptionType.merge(
-    s1_itlbException,
-    s1_pmpException
-  )
+  private val s1_exceptionOut = VecInit((s1_itlbException zip s1_pmpException).map { case (i, p) => i || p })
 
   /**
     ******************************************************************************
@@ -418,7 +415,7 @@ class ICacheMainPipe(implicit p: Parameters) extends ICacheModule
   private val s2_shouldFetch = VecInit((0 until PortNumber).map { i =>
     (!s2_hits(i) || s2_corruptRefetch(i)) &&
     (if (i == 0) true.B else s2_doubleline) &&
-    !ExceptionType.hasException(s2_exception.take(i + 1)) &&
+    s2_exception.take(i + 1).map(_.isNone).reduce(_ && _) &&
     s2_isMmio.take(i + 1).map(!_).reduce(_ && _)
   })
 
@@ -446,14 +443,11 @@ class ICacheMainPipe(implicit p: Parameters) extends ICacheModule
   private val s2_fetchFinish = !s2_shouldFetch.reduce(_ || _)
 
   // also raise af if l2 corrupt is detected
-  private val s2_l2Exception = VecInit(s2_l2Corrupt.map(ExceptionType.fromTilelink))
+  private val s2_l2Exception = VecInit(s2_l2Corrupt.map(corrupt => ExceptionType(hasAf = corrupt)))
   // NOTE: do NOT raise af if meta/data corrupt is detected, they are automatically recovered by re-fetching from L2
 
-  // merge s2 exceptions, itlb has the highest priority, then l2
-  private val s2_exceptionOut = ExceptionType.merge(
-    s2_exception, // includes itlb/pmp exception
-    s2_l2Exception
-  )
+  // merge s2 exceptions, itlb/pmp has the highest priority, then l2
+  private val s2_exceptionOut = VecInit((s2_exception zip s2_l2Exception).map { case (in, l2) => in || l2 })
 
   /**
     ******************************************************************************
@@ -468,7 +462,7 @@ class ICacheMainPipe(implicit p: Parameters) extends ICacheModule
   toIfu.bits.pAddr              := s2_pAddr
   (0 until PortNumber).foreach { i =>
     val needThisLine = if (i == 0) true.B else s2_doubleline
-    toIfu.bits.exception(i) := Mux(needThisLine, s2_exceptionOut(i), ExceptionType.none)
+    toIfu.bits.exception(i) := Mux(needThisLine, s2_exceptionOut(i), ExceptionType.None)
     toIfu.bits.pmpMmio(i)   := Mux(needThisLine, s2_pmpMmio(i), false.B)
     toIfu.bits.itlbPbmt(i)  := Mux(needThisLine, s2_itlbPbmt(i), Pbmt.pma)
   }
@@ -507,11 +501,11 @@ class ICacheMainPipe(implicit p: Parameters) extends ICacheModule
   io.perf.hit0Miss1    := s2_hits(0) && !s2_hits(1) && s2_doubleline
   io.perf.miss0Hit1    := !s2_hits(0) && s2_hits(1) && s2_doubleline
   io.perf.miss0Miss1   := !s2_hits(0) && !s2_hits(1) && s2_doubleline
-  io.perf.hit0Except1  := s2_hits(0) && ExceptionType.hasException(s2_exception(1)) && s2_doubleline
-  io.perf.miss0Except1 := !s2_hits(0) && ExceptionType.hasException(s2_exception(1)) && s2_doubleline
+  io.perf.hit0Except1  := s2_hits(0) && s2_exception(1).hasException && s2_doubleline
+  io.perf.miss0Except1 := !s2_hits(0) && s2_exception(1).hasException && s2_doubleline
   io.perf.bankHit(0)   := s2_hits(0)
   io.perf.bankHit(1)   := s2_hits(1) && s2_doubleline
-  io.perf.except0      := ExceptionType.hasException(s2_exception(0))
+  io.perf.except0      := s2_exception(0).hasException
   io.perf.hit          := s2_hits(0) && (!s2_doubleline || s2_hits(1))
 
   /** <PERF> fetch bubble generated by icache miss */
@@ -553,7 +547,7 @@ class ICacheMainPipe(implicit p: Parameters) extends ICacheModule
     */
   if (env.EnableDifftest) {
     val discards = (0 until PortNumber).map { i =>
-      ExceptionType.hasException(toIfu.bits.exception(i)) ||
+      toIfu.bits.exception(i).hasException ||
       toIfu.bits.pmpMmio(i) ||
       Pbmt.isUncache(toIfu.bits.itlbPbmt(i))
     }

src/main/scala/xiangshan/frontend/icache/ICachePrefetchPipe.scala

@@ -22,13 +22,12 @@ import utility.DataHoldBypass
 import utility.PriorityMuxDefault
 import utility.ValidHold
 import utility.XSPerfAccumulate
-import utils.NamedUInt
+import utils.EnumUInt
 import xiangshan.cache.mmu.Pbmt
 import xiangshan.cache.mmu.TlbCmd
 import xiangshan.cache.mmu.TlbRequestIO
 import xiangshan.cache.mmu.ValidHoldBypass // FIXME: should move this to utility?
 import xiangshan.frontend.ExceptionType
-import xiangshan.frontend.PrunedAddr
 import xiangshan.frontend.PrunedAddrInit
 import xiangshan.frontend.ftq.BpuFlushInfo
 
@@ -117,7 +116,7 @@ class ICachePrefetchPipe(implicit p: Parameters) extends ICacheModule
   private val s1_backendException = RegEnable(s0_backendException, 0.U.asTypeOf(s0_backendException), s0_fire)
 
   private def nS1FsmState: Int = 5
-  private object S1FsmState extends NamedUInt(log2Up(nS1FsmState)) {
+  private object S1FsmState extends EnumUInt(nS1FsmState) {
     def Idle:       UInt = 0.U(width.W)
     def ItlbResend: UInt = 1.U(width.W)
     def MetaResend: UInt = 2.U(width.W)
@@ -185,7 +184,7 @@ class ICachePrefetchPipe(implicit p: Parameters) extends ICacheModule
     Mux(tlbValidPulse(i), s1_pAddrWire(i), s1_pAddrReg(i))
   })
   private val s1_itlbExceptionRaw = VecInit((0 until PortNumber).map { i =>
-    DataHoldBypass(ExceptionType.fromTlbResp(fromItlb(i).bits), 0.U(ExceptionType.width.W), tlbValidPulse(i))
+    DataHoldBypass(ExceptionType.fromTlbResp(fromItlb(i).bits), ExceptionType.None, tlbValidPulse(i))
   })
   private val s1_itlbPbmt = VecInit((0 until PortNumber).map { i =>
     DataHoldBypass(fromItlb(i).bits.pbmt(0), 0.U.asTypeOf(fromItlb(i).bits.pbmt(0)), tlbValidPulse(i))
@@ -207,10 +206,7 @@ class ICachePrefetchPipe(implicit p: Parameters) extends ICacheModule
   // merge backend exception and itlb exception
   // for area concern, we don't have 64 bits vaddr in frontend, but spec asks page fault when high bits are not all 0/1
   // this check is finished in backend, and passed to frontend with redirect, we see it as a part of itlb exception
-  private val s1_itlbException = ExceptionType.merge(
-    s1_backendException,
-    s1_itlbExceptionRaw
-  )
+  private val s1_itlbException = VecInit((s1_backendException zip s1_itlbExceptionRaw).map { case (b, i) => b || i })
   // debug
   dontTouch(s1_itlbExceptionRaw)
   dontTouch(s1_itlbException)
@@ -221,7 +217,7 @@ class ICachePrefetchPipe(implicit p: Parameters) extends ICacheModule
    *       see GPAMem: https://github.com/OpenXiangShan/XiangShan/blob/344cf5d55568dd40cd658a9ee66047a505eeb504/src/main/scala/xiangshan/backend/GPAMem.scala#L33-L34
    *       see also: https://github.com/OpenXiangShan/XiangShan/blob/344cf5d55568dd40cd658a9ee66047a505eeb504/src/main/scala/xiangshan/frontend/IFU.scala#L374-L375
    */
-  private val s1_itlbExceptionIsGpf = VecInit(s1_itlbException.map(_ === ExceptionType.gpf))
+  private val s1_itlbExceptionIsGpf = VecInit(s1_itlbException.map(_.isGpf))
   private val s1_gpAddr = PriorityMuxDefault(
     s1_itlbExceptionIsGpf zip (0 until PortNumber).map(i => s1_gpAddrRaw(i) - (i << blockOffBits).U),
     0.U.asTypeOf(s1_gpAddrRaw(0))
@@ -326,7 +322,7 @@ class ICachePrefetchPipe(implicit p: Parameters) extends ICacheModule
     toWayLookup.bits.itlbException(i) := Mux(
       excpValid,
       s1_itlbException(i), // includes backend exception
-      ExceptionType.none
+      ExceptionType.None
     )
     toWayLookup.bits.itlbPbmt(i) := Mux(excpValid, s1_itlbPbmt(i), Pbmt.pma)
   }
@@ -359,15 +355,12 @@ class ICachePrefetchPipe(implicit p: Parameters) extends ICacheModule
     p.bits.size := 3.U
     p.bits.cmd  := TlbCmd.exec
   }
-  private val s1_pmpException = VecInit(fromPmp.map(ExceptionType.fromPMPResp))
+  private val s1_pmpException = VecInit(fromPmp.map(ExceptionType.fromPmpResp))
   private val s1_pmpMmio      = VecInit(fromPmp.map(_.mmio))
 
   // merge s1 itlb/pmp exceptions, itlb has the highest priority, pmp next
-  // for timing consideration, meta_corrupt is not merged, and it will NOT cancel prefetch
-  private val s1_exceptionOut = ExceptionType.merge(
-    s1_itlbException, // includes backend exception
-    s1_pmpException
-  )
+  // here, itlb exception includes backend exception
+  private val s1_exceptionOut = VecInit((s1_itlbException zip s1_pmpException).map { case (i, p) => i || p })
 
   // merge pmp mmio and itlb pbmt
   private val s1_isMmio = VecInit((s1_pmpMmio zip s1_itlbPbmt).map { case (mmio, pbmt) =>
@@ -503,7 +496,7 @@ class ICachePrefetchPipe(implicit p: Parameters) extends ICacheModule
    */
   private val s2_miss = VecInit((0 until PortNumber).map { i =>
     !s2_hits(i) && (if (i == 0) true.B else s2_doubleline) &&
-    !ExceptionType.hasException(s2_exception.take(i + 1)) &&
+    s2_exception.take(i + 1).map(_.isNone).reduce(_ && _) &&
     s2_isMmio.take(i + 1).map(!_).reduce(_ && _)
   })
 

src/main/scala/xiangshan/frontend/icache/ICacheWayLookup.scala

@@ -123,7 +123,7 @@ class ICacheWayLookup(implicit p: Parameters) extends ICacheModule with ICacheMi
   io.write.ready := !full && !gpfStall
   when(io.write.fire) {
     entries(writePtr.value) := io.write.bits.entry
-    when(io.write.bits.itlbException.map(_ === ExceptionType.gpf).reduce(_ || _)) {
+    when(io.write.bits.itlbException.map(_.isGpf).reduce(_ || _)) {
       // if gpfEntry is bypassed, we don't need to save it
       // note this will override the read (L156)
       gpfEntry.valid := !(canBypass && io.read.fire)

src/main/scala/xiangshan/frontend/ifu/Bundles.scala

@@ -18,7 +18,7 @@ package xiangshan.frontend.ifu
 import chisel3._
 import chisel3.util._
 import org.chipsalliance.cde.config.Parameters
-import utils.NamedUInt
+import utils.EnumUInt
 import xiangshan.frontend.PrunedAddr
 
 /* ***
@@ -32,14 +32,14 @@ import xiangshan.frontend.PrunedAddr
  * *** */
 
 /* ***** PreDecode ***** */
-object PreDecodeFaultType extends NamedUInt(3) {
-  def noFault:      UInt = "b000".U(width.W)
-  def jalFault:     UInt = "b001".U(width.W) // not CFI taken or invalid instruction taken
-  def retFault:     UInt = "b010".U(width.W) // not CFI taken or invalid instruction taken
-  def targetFault:  UInt = "b011".U(width.W)
-  def notCfiFault:  UInt = "b100".U(width.W) // not CFI taken or invalid instruction taken
-  def invalidTaken: UInt = "b101".U(width.W)
-  def jalrFault:    UInt = "b110".U(width.W)
+object PreDecodeFaultType extends EnumUInt(7) {
+  def NoFault:      UInt = 0.U(width.W)
+  def JalFault:     UInt = 1.U(width.W) // not CFI taken or invalid instruction taken
+  def RetFault:     UInt = 2.U(width.W) // not CFI taken or invalid instruction taken
+  def TargetFault:  UInt = 3.U(width.W)
+  def NotCfiFault:  UInt = 4.U(width.W) // not CFI taken or invalid instruction taken
+  def InvalidTaken: UInt = 5.U(width.W)
+  def JalrFault:    UInt = 6.U(width.W)
 }
 
 /* ***** Ifu last half ***** */

src/main/scala/xiangshan/frontend/ifu/Helpers.scala

@@ -31,14 +31,14 @@ trait PreDecodeHelper extends HasXSParameter {
   def isLink(reg: UInt): Bool = reg === 1.U || reg === 5.U
 
   def getBrType(inst: UInt): UInt =
-    ListLookup(inst, List(BrType.notCFI), PreDecodeInst.brTable).head
+    ListLookup(inst, List(BrType.NotCfi), PreDecodeInst.brTable).head
 
   def getBrInfo(inst: UInt): (UInt, Bool, Bool) = {
     val brType = getBrType(inst)
     val rd     = Mux(isRVC(inst), inst(12), inst(11, 7))
-    val rs     = Mux(isRVC(inst), Mux(brType === BrType.jal, 0.U, inst(11, 7)), inst(19, 15))
-    val isCall = (brType === BrType.jal && !isRVC(inst) || brType === BrType.jalr) && isLink(rd) // Only for RV64
-    val isRet  = brType === BrType.jalr && isLink(rs) && !isCall
+    val rs     = Mux(isRVC(inst), Mux(brType === BrType.Jal, 0.U, inst(11, 7)), inst(19, 15))
+    val isCall = (brType === BrType.Jal && !isRVC(inst) || brType === BrType.Jalr) && isLink(rd) // Only for RV64
+    val isRet  = brType === BrType.Jalr && isLink(rs) && !isCall
     (brType, isCall, isRet)
   }
 

src/main/scala/xiangshan/frontend/ifu/Ifu.scala

@@ -32,7 +32,7 @@ import utility.XSDebug
 import utility.XSError
 import utility.XSPerfAccumulate
 import utility.XSPerfHistogram
-import utils.NamedUInt
+import utils.EnumUInt
 import xiangshan.FrontendTdataDistributeIO
 import xiangshan.RedirectLevel
 import xiangshan.RobCommitInfo
@@ -331,21 +331,19 @@ class Ifu(implicit p: Parameters) extends IfuModule
 
   // FIXME: raise af if one fetch block crosses the cacheable/un-cacheable boundary, might not correct
   private val s2_mmioMismatchException = VecInit(Seq(
-    ExceptionType.none, // mark the exception only on the second line
-    Mux(
-      // not double-line, skip check
-      !fromICache.bits.doubleline || (
+    ExceptionType.None, // mark the exception only on the second line
+    ExceptionType(hasAf =
+      // if not double-line, skip check
+      fromICache.bits.doubleline && (
         // is double-line, ask for consistent pmp_mmio and itlb_pbmt value
-        fromICache.bits.pmpMmio(0) === fromICache.bits.pmpMmio(1) &&
-          fromICache.bits.itlbPbmt(0) === fromICache.bits.itlbPbmt(1)
-      ),
-      ExceptionType.none,
-      ExceptionType.af
+        fromICache.bits.pmpMmio(0) =/= fromICache.bits.pmpMmio(1) ||
+          fromICache.bits.itlbPbmt(0) =/= fromICache.bits.itlbPbmt(1)
+      )
     )
   ))
 
   // merge exceptions
-  private val s2_exception = ExceptionType.merge(s2_exceptionIn, s2_mmioMismatchException)
+  private val s2_exception = VecInit((s2_exceptionIn zip s2_mmioMismatchException).map { case (in, m) => in || m })
 
   // we need only the first port, as the second is asked to be the same
   private val s2_pmpMmio  = fromICache.bits.pmpMmio(0)
@@ -379,7 +377,7 @@ class Ifu(implicit p: Parameters) extends IfuModule
   private val s2_instrRange = s2_jumpRange & s2_ftrRange
   private val s2_exceptionVec = VecInit((0 until PredictWidth).map(i =>
     MuxCase(
-      ExceptionType.none,
+      ExceptionType.None,
       Seq(
         !isNextLine(s2_pc(i), s2_ftqReq.startAddr)                   -> s2_exception(0),
         (isNextLine(s2_pc(i), s2_ftqReq.startAddr) && s2_doubleline) -> s2_exception(1)
@@ -454,9 +452,9 @@ class Ifu(implicit p: Parameters) extends IfuModule
    */
   private val s2_crossPageExceptionVec = VecInit((0 until PredictWidth).map { i =>
     Mux(
-      isLastInLine(s2_pc(i)) && !s2_pd(i).isRVC && s2_doubleline && !ExceptionType.hasException(s2_exception(0)),
+      isLastInLine(s2_pc(i)) && !s2_pd(i).isRVC && s2_doubleline && s2_exception(0).isNone,
       s2_exception(1),
-      ExceptionType.none
+      ExceptionType.None
     )
   })
   XSPerfAccumulate("fetch_bubble_icache_not_resp", s2_valid && !icacheRespAllValid)
@@ -563,7 +561,7 @@ class Ifu(implicit p: Parameters) extends IfuModule
 
   /* *** mmio *** */
   private def nMmioFsmState = 11
-  private object MmioFsmState extends NamedUInt(log2Up(nMmioFsmState)) {
+  private object MmioFsmState extends EnumUInt(nMmioFsmState) {
     def Idle:           UInt = 0.U(width.W)
     def WaitLastCommit: UInt = 1.U(width.W)
     def SendReq:        UInt = 2.U(width.W)
@@ -580,7 +578,7 @@ class Ifu(implicit p: Parameters) extends IfuModule
   private val mmioState = RegInit(MmioFsmState.Idle)
 
   private val mmioData       = RegInit(VecInit(Seq.fill(2)(0.U(16.W))))
-  private val mmioException  = RegInit(0.U(ExceptionType.width.W))
+  private val mmioException  = RegInit(ExceptionType.None)
   private val mmioIsRvc      = RegInit(false.B)
   private val mmioHasResend  = RegInit(false.B)
   private val mmioResendAddr = RegInit(PrunedAddrInit(0.U(PAddrBits.W)))
@@ -591,7 +589,7 @@ class Ifu(implicit p: Parameters) extends IfuModule
   private def mmioReset(): Unit = {
     mmioState := MmioFsmState.Idle
     mmioData.foreach(_ := 0.U)
-    mmioException               := ExceptionType.none
+    mmioException               := ExceptionType.None
     mmioIsRvc                   := false.B
     mmioHasResend               := false.B
     mmioResendAddr              := PrunedAddrInit(0.U(PAddrBits.W))
@@ -607,7 +605,7 @@ class Ifu(implicit p: Parameters) extends IfuModule
 
   // do mmio fetch only when pmp/pbmt shows it is a un-cacheable address and no exception occurs
   private val s3_reqIsMmio =
-    s3_valid && (s3_pmpMmio || Pbmt.isUncache(s3_itlbPbmt)) && !ExceptionType.hasException(s3_exception)
+    s3_valid && (s3_pmpMmio || Pbmt.isUncache(s3_itlbPbmt)) && s3_exception.map(_.isNone).reduce(_ && _)
   private val mmioCommit = VecInit(io.robCommits.map { commit =>
     commit.valid && commit.bits.ftqIdx === s3_ftqReq.ftqIdx && commit.bits.ftqOffset === 0.U
   }).asUInt.orR
@@ -682,9 +680,9 @@ class Ifu(implicit p: Parameters) extends IfuModule
     is(MmioFsmState.WaitResp) {
       when(fromUncache.fire) {
         val respIsRVC = isRVC(fromUncache.bits.data(1, 0))
-        val exception = ExceptionType.fromTilelink(fromUncache.bits.corrupt)
+        val exception = ExceptionType(hasAf = fromUncache.bits.corrupt)
         // when response is not RVC, and lower bits of pAddr is 6 => request crosses 8B boundary, need resend
-        val needResend = !respIsRVC && s3_pAddr(0)(2, 1) === 3.U && !ExceptionType.hasException(exception)
+        val needResend = !respIsRVC && s3_pAddr(0)(2, 1) === 3.U && exception.isNone
         mmioState     := Mux(needResend, MmioFsmState.SendTlb, MmioFsmState.WaitCommit)
         mmioException := exception
         mmioIsRvc     := respIsRVC
@@ -702,16 +700,13 @@ class Ifu(implicit p: Parameters) extends IfuModule
       when(io.itlb.resp.fire) {
         // we are using a blocked tlb, so resp.fire must have !resp.bits.miss
         assert(!io.itlb.resp.bits.miss, "blocked mode iTLB miss when resp.fire")
-        val tlbException = ExceptionType.fromTlbResp(io.itlb.resp.bits)
+        val itlbException = ExceptionType.fromTlbResp(io.itlb.resp.bits)
         // if itlb re-check respond pbmt mismatch with previous check, must be access fault
-        val pbmtMismatchException = Mux(
-          io.itlb.resp.bits.pbmt(0) =/= s3_itlbPbmt,
-          ExceptionType.af,
-          ExceptionType.none
-        )
-        val exception = ExceptionType.merge(tlbException, pbmtMismatchException)
+        val pbmtMismatchException = ExceptionType(hasAf = io.itlb.resp.bits.pbmt(0) =/= s3_itlbPbmt)
+        // merge, itlbException has higher priority
+        val exception = itlbException || pbmtMismatchException
         // if tlb has exception, abort checking pmp, just send instr & exception to iBuffer and wait for commit
-        mmioState := Mux(ExceptionType.hasException(exception), MmioFsmState.WaitCommit, MmioFsmState.SendPmp)
+        mmioState := Mux(exception.hasException, MmioFsmState.WaitCommit, MmioFsmState.SendPmp)
         // also save itlb response
         mmioException               := exception
         mmioResendAddr              := io.itlb.resp.bits.paddr(0)
@@ -721,16 +716,13 @@ class Ifu(implicit p: Parameters) extends IfuModule
     }
 
     is(MmioFsmState.SendPmp) {
-      val pmpException = ExceptionType.fromPMPResp(io.pmp.resp)
+      val pmpException = ExceptionType.fromPmpResp(io.pmp.resp)
       // if pmp re-check respond mismatch with previous check, must be access fault
-      val mmioMismatchException = Mux(
-        io.pmp.resp.mmio =/= s3_pmpMmio,
-        ExceptionType.af,
-        ExceptionType.none
-      )
-      val exception = ExceptionType.merge(pmpException, mmioMismatchException)
+      val mmioMismatchException = ExceptionType(hasAf = io.pmp.resp.mmio =/= s3_pmpMmio)
+      // merge, pmpException has higher priority
+      val exception = pmpException || mmioMismatchException
       // if pmp has exception, abort sending request, just send instr & exception to iBuffer and wait for commit
-      mmioState := Mux(ExceptionType.hasException(exception), MmioFsmState.WaitCommit, MmioFsmState.ResendReq)
+      mmioState := Mux(exception.hasException, MmioFsmState.WaitCommit, MmioFsmState.ResendReq)
       // also save pmp response
       mmioException := exception
     }
@@ -742,7 +734,7 @@ class Ifu(implicit p: Parameters) extends IfuModule
     is(MmioFsmState.WaitResendResp) {
       when(fromUncache.fire) {
         mmioState     := MmioFsmState.WaitCommit
-        mmioException := ExceptionType.fromTilelink(fromUncache.bits.corrupt)
+        mmioException := ExceptionType(hasAf = fromUncache.bits.corrupt)
         mmioData(1)   := fromUncache.bits.data(15, 0)
       }
     }
@@ -860,8 +852,10 @@ class Ifu(implicit p: Parameters) extends IfuModule
     a.bits  := i.U
     a.valid := checkerOutStage1.fixedTaken(i) && !s3_reqIsMmio
   }
-  io.toIBuffer.bits.foldpc        := s3_foldPc
-  io.toIBuffer.bits.exceptionType := ExceptionType.merge(s3_exceptionVec, s3_crossPageExceptionVec)
+  io.toIBuffer.bits.foldpc := s3_foldPc
+  io.toIBuffer.bits.exceptionType := VecInit((s3_exceptionVec zip s3_crossPageExceptionVec).map { case (e, ce) =>
+    e || ce // merge, cross page fix has lower priority
+  })
   // backendException only needs to be set for the first instruction.
   // Other instructions in the same block may have pf or af set,
   // which is a side effect of the first instruction and actually not necessary.
@@ -869,7 +863,7 @@ class Ifu(implicit p: Parameters) extends IfuModule
     case 0 => s3_isBackendException
     case _ => false.B
   }
-  io.toIBuffer.bits.crossPageIPFFix := s3_crossPageExceptionVec.map(ExceptionType.hasException)
+  io.toIBuffer.bits.crossPageIPFFix := s3_crossPageExceptionVec.map(_.hasException)
   io.toIBuffer.bits.illegalInstr    := s3_ill
   io.toIBuffer.bits.triggered       := s3_triggered
 
@@ -899,8 +893,8 @@ class Ifu(implicit p: Parameters) extends IfuModule
   // s3_gpAddr is valid iff gpf is detected
   io.toBackend.gpaddrMem_wen := s3_toIBufferValid && Mux(
     s3_reqIsMmio,
-    mmioException === ExceptionType.gpf,
-    s3_exception.map(_ === ExceptionType.gpf).reduce(_ || _)
+    mmioException.isGpf,
+    s3_exception.map(_.isGpf).reduce(_ || _)
   )
   io.toBackend.gpaddrMem_waddr        := s3_ftqReq.ftqIdx.value
   io.toBackend.gpaddrMem_wdata.gpaddr := Mux(s3_reqIsMmio, mmioResendGpAddr.toUInt, s3_gpAddr.toUInt)
@@ -951,7 +945,7 @@ class Ifu(implicit p: Parameters) extends IfuModule
 
     io.toIBuffer.bits.exceptionType(0) := mmioException
     // exception can happen in next page only when resend
-    io.toIBuffer.bits.crossPageIPFFix(0) := mmioHasResend && ExceptionType.hasException(mmioException)
+    io.toIBuffer.bits.crossPageIPFFix(0) := mmioHasResend && mmioException.hasException
     io.toIBuffer.bits.illegalInstr(0)    := mmioRvcExpander.io.ill
 
     io.toIBuffer.bits.enqEnable := s3_mmioRange.asUInt
@@ -1053,12 +1047,12 @@ class Ifu(implicit p: Parameters) extends IfuModule
 
   /* write back flush type */
   private val checkFaultType    = wbCheckResultStage2.faultType
-  private val checkJalFault     = wbValid && checkFaultType.map(_ === PreDecodeFaultType.jalFault).reduce(_ || _)
-  private val checkJalrFault    = wbValid && checkFaultType.map(_ === PreDecodeFaultType.jalrFault).reduce(_ || _)
-  private val checkRetFault     = wbValid && checkFaultType.map(_ === PreDecodeFaultType.retFault).reduce(_ || _)
-  private val checkTargetFault  = wbValid && checkFaultType.map(_ === PreDecodeFaultType.targetFault).reduce(_ || _)
-  private val checkNotCFIFault  = wbValid && checkFaultType.map(_ === PreDecodeFaultType.notCfiFault).reduce(_ || _)
-  private val checkInvalidTaken = wbValid && checkFaultType.map(_ === PreDecodeFaultType.invalidTaken).reduce(_ || _)
+  private val checkJalFault     = wbValid && checkFaultType.map(_ === PreDecodeFaultType.JalFault).reduce(_ || _)
+  private val checkJalrFault    = wbValid && checkFaultType.map(_ === PreDecodeFaultType.JalrFault).reduce(_ || _)
+  private val checkRetFault     = wbValid && checkFaultType.map(_ === PreDecodeFaultType.RetFault).reduce(_ || _)
+  private val checkTargetFault  = wbValid && checkFaultType.map(_ === PreDecodeFaultType.TargetFault).reduce(_ || _)
+  private val checkNotCFIFault  = wbValid && checkFaultType.map(_ === PreDecodeFaultType.NotCfiFault).reduce(_ || _)
+  private val checkInvalidTaken = wbValid && checkFaultType.map(_ === PreDecodeFaultType.InvalidTaken).reduce(_ || _)
 
   XSPerfAccumulate("predecode_flush_jalFault", checkJalFault)
   XSPerfAccumulate("predecode_flush_jalrFault", checkJalrFault)

src/main/scala/xiangshan/frontend/ifu/PredChecker.scala

@@ -139,14 +139,14 @@ class PredChecker(implicit p: Parameters) extends IfuModule {
 
   io.resp.stage2Out.faultType.zipWithIndex.foreach { case (faultType, i) =>
     faultType := MuxCase(
-      PreDecodeFaultType.noFault,
+      PreDecodeFaultType.NoFault,
       Seq(
-        jalFaultVecNext(i)  -> PreDecodeFaultType.jalFault,
-        jalrFaultVecNext(i) -> PreDecodeFaultType.jalrFault,
-        retFaultVecNext(i)  -> PreDecodeFaultType.retFault,
-        targetFault(i)      -> PreDecodeFaultType.targetFault,
-        notCFITakenNext(i)  -> PreDecodeFaultType.notCfiFault,
-        invalidTakenNext(i) -> PreDecodeFaultType.invalidTaken
+        jalFaultVecNext(i)  -> PreDecodeFaultType.JalFault,
+        jalrFaultVecNext(i) -> PreDecodeFaultType.JalrFault,
+        retFaultVecNext(i)  -> PreDecodeFaultType.RetFault,
+        targetFault(i)      -> PreDecodeFaultType.TargetFault,
+        notCFITakenNext(i)  -> PreDecodeFaultType.NotCfiFault,
+        invalidTakenNext(i) -> PreDecodeFaultType.InvalidTaken
       )
     )
   }

src/main/scala/xiangshan/frontend/instruncache/InstrUncacheEntry.scala

@@ -21,7 +21,7 @@ import freechips.rocketchip.tilelink.TLBundleA
 import freechips.rocketchip.tilelink.TLBundleD
 import freechips.rocketchip.tilelink.TLEdgeOut
 import org.chipsalliance.cde.config.Parameters
-import utils.NamedUInt
+import utils.EnumUInt
 
 // One miss entry deals with one mmio request
 class InstrUncacheEntry(edge: TLEdgeOut)(implicit p: Parameters) extends InstrUncacheModule {
@@ -40,7 +40,7 @@ class InstrUncacheEntry(edge: TLEdgeOut)(implicit p: Parameters) extends InstrUn
   val io: InstrUncacheEntryIO = IO(new InstrUncacheEntryIO(edge))
 
   private def nState: Int = 4
-  private object State extends NamedUInt(log2Up(nState)) {
+  private object State extends EnumUInt(nState) {
     def Invalid:    UInt = 0.U(width.W)
     def RefillReq:  UInt = 1.U(width.W)
     def RefillResp: UInt = 2.U(width.W)