xref: /XiangShan/src/main/scala/xiangshan/frontend/IFU.scala (revision 35ee668dfaa9d1512c3dfbcc845d4c6a4c4ec9be)
1// /***************************************************************************************
2// * Copyright (c) 2020-2021 Institute of Computing Technology, Chinese Academy of Sciences
3// *
4// * XiangShan is licensed under Mulan PSL v2.
5// * You can use this software according to the terms and conditions of the Mulan PSL v2.
6// * You may obtain a copy of Mulan PSL v2 at:
7// *          http://license.coscl.org.cn/MulanPSL2
8// *
9// * THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
10// * EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
11// * MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
12// *
13// * See the Mulan PSL v2 for more details.
14// ***************************************************************************************/
15
16// package xiangshan.frontend
17
18// import chipsalliance.rocketchip.config.Parameters
19// import chisel3._
20// import chisel3.util._
21// import xiangshan._
22// import utils._
23// import xiangshan.cache._
24// import chisel3.experimental.chiselName
25// import freechips.rocketchip.tile.HasLazyRoCC
26// import system.L1CacheErrorInfo
27
28// trait HasInstrMMIOConst extends HasXSParameter with HasIFUConst{
29//   def mmioBusWidth = 64
30//   def mmioBusBytes = mmioBusWidth /8
31//   def mmioBeats = FetchWidth * 4 * 8 / mmioBusWidth
32//   def mmioMask  = VecInit(List.fill(PredictWidth)(true.B)).asUInt
33//   def mmioBusAligned(pc :UInt): UInt = align(pc, mmioBusBytes)
34// }
35
36// trait HasIFUConst extends HasXSParameter {
37//   val resetVector = 0x10000000L//TODO: set reset vec
38//   def align(pc: UInt, bytes: Int): UInt = Cat(pc(VAddrBits-1, log2Ceil(bytes)), 0.U(log2Ceil(bytes).W))
39//   val groupBytes = 64 // correspond to cache line size
40//   val groupOffsetBits = log2Ceil(groupBytes)
41//   val groupWidth = groupBytes / instBytes
42//   val packetBytes = PredictWidth * instBytes
43//   val packetOffsetBits = log2Ceil(packetBytes)
44//   def offsetInPacket(pc: UInt) = pc(packetOffsetBits-1, instOffsetBits)
45//   def packetIdx(pc: UInt) = pc(VAddrBits-1, log2Ceil(packetBytes))
46//   def groupAligned(pc: UInt)  = align(pc, groupBytes)
47//   def packetAligned(pc: UInt) = align(pc, packetBytes)
48//   def mask(pc: UInt): UInt = ((~(0.U(PredictWidth.W))) << offsetInPacket(pc))(PredictWidth-1,0)
49//   def snpc(pc: UInt): UInt = packetAligned(pc) + packetBytes.U
50
51//   val enableGhistRepair = true
52//   val IFUDebug = true
53// }
54
55// class GlobalHistory(implicit p: Parameters) extends XSBundle {
56//   val predHist = UInt(HistoryLength.W)
57//   def update(sawNTBr: Bool, takenOnBr: Bool, hist: UInt = predHist): GlobalHistory = {
58//     val g = Wire(new GlobalHistory)
59//     val shifted = takenOnBr || sawNTBr
60//     g.predHist := Mux(shifted, (hist << 1) | takenOnBr.asUInt, hist)
61//     g
62//   }
63
64//   final def === (that: GlobalHistory): Bool = {
65//     predHist === that.predHist
66//   }
67
68//   final def =/= (that: GlobalHistory): Bool = !(this === that)
69
70//   implicit val name = "IFU"
71//   def debug(where: String) = XSDebug(p"[${where}_GlobalHistory] hist=${Binary(predHist)}\n")
72//   // override def toString(): String = "histPtr=%d, sawNTBr=%d, takenOnBr=%d, saveHalfRVI=%d".format(histPtr, sawNTBr, takenOnBr, saveHalfRVI)
73// }
74
75
76// class IFUIO(implicit p: Parameters) extends XSBundle
77// {
78//   // to ibuffer
79//   val fetchPacket = DecoupledIO(new FetchPacket)
80//   // from backend
81//   val redirect = Flipped(ValidIO(new Redirect))
82//   val bp_ctrl = Input(new BPUCtrl)
83//   val commitUpdate = Flipped(ValidIO(new FtqEntry))
84//   val ftqEnqPtr = Input(new FtqPtr)
85//   val ftqLeftOne = Input(Bool())
86//   // to backend
87//   val toFtq = DecoupledIO(new FtqEntry)
88//   // to icache
89//   val icacheMemGrant = Flipped(DecoupledIO(new L1plusCacheResp))
90//   val fencei = Input(Bool())
91//   // from icache
92//   val icacheMemAcq = DecoupledIO(new L1plusCacheReq)
93//   val l1plusFlush = Output(Bool())
94//   val prefetchTrainReq = ValidIO(new IcacheMissReq)
95//   val error = new L1CacheErrorInfo
96//   // to tlb
97//   val sfence = Input(new SfenceBundle)
98//   val tlbCsr = Input(new TlbCsrBundle)
99//   // from tlb
100//   val ptw = new TlbPtwIO
101//   // icache uncache
102//   val mmio_acquire = DecoupledIO(new InsUncacheReq)
103//   val mmio_grant  = Flipped(DecoupledIO(new InsUncacheResp))
104//   val mmio_flush = Output(Bool())
105// }
106
107// class PrevHalfInstr(implicit p: Parameters) extends XSBundle {
108//   val pc = UInt(VAddrBits.W)
109//   val npc = UInt(VAddrBits.W)
110//   val instr = UInt(16.W)
111//   val ipf = Bool()
112// }
113
114// @chiselName
115// class IFU(implicit p: Parameters) extends XSModule with HasIFUConst with HasCircularQueuePtrHelper
116// {
117//   val io = IO(new IFUIO)
118//   val bpu = BPU(EnableBPU)
119//   val icache = Module(new ICache)
120
121//   io.ptw <> TLB(
122//     in = Seq(icache.io.tlb),
123//     sfence = io.sfence,
124//     csr = io.tlbCsr,
125//     width = 1,
126//     isDtlb = false,
127//     shouldBlock = true
128//   )
129
130//   val if2_redirect, if3_redirect, if4_redirect = WireInit(false.B)
131//   val if1_flush, if2_flush, if3_flush, if4_flush = WireInit(false.B)
132
133//   val icacheResp = icache.io.resp.bits
134
135//   if4_flush := io.redirect.valid
136//   if3_flush := if4_flush || if4_redirect
137//   if2_flush := if3_flush || if3_redirect
138//   if1_flush := if2_flush || if2_redirect
139
140//   //********************** IF1 ****************************//
141//   val if1_valid = !reset.asBool && GTimer() > 500.U
142//   val if1_npc = WireInit(0.U(VAddrBits.W))
143//   val if2_ready = WireInit(false.B)
144//   val if2_valid = RegInit(init = false.B)
145//   val if2_allReady = WireInit(if2_ready && icache.io.req.ready && bpu.io.in_ready)
146//   val if1_fire = if1_valid &&  if2_allReady
147
148//   val if1_gh, if2_gh, if3_gh, if4_gh = Wire(new GlobalHistory)
149//   val if2_predicted_gh, if3_predicted_gh, if4_predicted_gh = Wire(new GlobalHistory)
150//   val final_gh = RegInit(0.U.asTypeOf(new GlobalHistory))
151
152//   //********************** IF2 ****************************//
153//   val if2_allValid = if2_valid && icache.io.tlb.resp.valid
154//   val if3_ready = WireInit(false.B)
155//   val if2_fire = if2_allValid && if3_ready
156//   val if2_pc = RegEnable(next = if1_npc, init = resetVector.U, enable = if1_fire)
157//   val if2_snpc = snpc(if2_pc)
158//   val if2_predHist = RegEnable(if1_gh.predHist, enable=if1_fire)
159//   if2_ready := if3_ready && icache.io.tlb.resp.valid || !if2_valid
160//   when (if1_fire)       { if2_valid := true.B }
161//   .elsewhen (if2_flush) { if2_valid := false.B }
162//   .elsewhen (if2_fire)  { if2_valid := false.B }
163
164//   val npcGen = new PriorityMuxGenerator[UInt]
165//   npcGen.register(true.B, RegNext(if1_npc), Some("stallPC"))
166//   val if2_bp = bpu.io.out(0)
167
168//   // if taken, bp_redirect should be true
169//   // when taken on half RVI, we suppress this redirect signal
170
171//   npcGen.register(if2_valid, Mux(if2_bp.taken, if2_bp.target, if2_snpc), Some("if2_target"))
172
173//   if2_predicted_gh := if2_gh.update(if2_bp.hasNotTakenBrs, if2_bp.takenOnBr)
174
175//   //********************** IF3 ****************************//
176//   // if3 should wait for instructions resp to arrive
177//   val if3_valid = RegInit(init = false.B)
178//   val if4_ready = WireInit(false.B)
179//   val if3_allValid = if3_valid && icache.io.resp.valid
180//   val if3_fire = if3_allValid && if4_ready
181//   val if3_pc = RegEnable(if2_pc, if2_fire)
182//   val if3_snpc = RegEnable(if2_snpc, if2_fire)
183//   val if3_predHist = RegEnable(if2_predHist, enable=if2_fire)
184//   if3_ready := if4_ready && icache.io.resp.valid || !if3_valid
185//   when (if3_flush) {
186//     if3_valid := false.B
187//   }.elsewhen (if2_fire && !if2_flush) {
188//     if3_valid := true.B
189//   }.elsewhen (if3_fire) {
190//     if3_valid := false.B
191//   }
192
193//   val if3_bp = bpu.io.out(1)
194//   if3_predicted_gh := if3_gh.update(if3_bp.hasNotTakenBrs, if3_bp.takenOnBr)
195
196
197//   val prevHalfInstrReq = WireInit(0.U.asTypeOf(ValidUndirectioned(new PrevHalfInstr)))
198//   // only valid when if4_fire
199//   val hasPrevHalfInstrReq = prevHalfInstrReq.valid && HasCExtension.B
200
201//   val if3_prevHalfInstr = RegInit(0.U.asTypeOf(ValidUndirectioned(new PrevHalfInstr)))
202
203//   // 32-bit instr crosses 2 pages, and the higher 16-bit triggers page fault
204//   val crossPageIPF = WireInit(false.B)
205
206//   val if3_pendingPrevHalfInstr = if3_prevHalfInstr.valid && HasCExtension.B
207
208//   // the previous half of RVI instruction waits until it meets its last half
209//   val if3_prevHalfInstrMet = if3_pendingPrevHalfInstr && if3_prevHalfInstr.bits.npc === if3_pc && if3_valid
210//   // set to invalid once consumed or redirect from backend
211//   val if3_prevHalfConsumed = if3_prevHalfInstrMet && if3_fire
212//   val if3_prevHalfFlush = if4_flush
213//   when (if3_prevHalfFlush) {
214//     if3_prevHalfInstr.valid := false.B
215//   }.elsewhen (hasPrevHalfInstrReq) {
216//     if3_prevHalfInstr.valid := true.B
217//   }.elsewhen (if3_prevHalfConsumed) {
218//     if3_prevHalfInstr.valid := false.B
219//   }
220//   when (hasPrevHalfInstrReq) {
221//     if3_prevHalfInstr.bits := prevHalfInstrReq.bits
222//   }
223//   // when bp signal a redirect, we distinguish between taken and not taken
224//   // if taken and saveHalfRVI is true, we do not redirect to the target
225
226//   class IF3_PC_COMP extends XSModule {
227//     val io = IO(new Bundle {
228//       val if2_pc = Input(UInt(VAddrBits.W))
229//       val pc     = Input(UInt(VAddrBits.W))
230//       val if2_valid = Input(Bool())
231//       val res = Output(Bool())
232//     })
233//     io.res := !io.if2_valid || io.if2_valid && io.if2_pc =/= io.pc
234//   }
235//   def if3_nextValidPCNotEquals(pc: UInt) = {
236//     val comp = Module(new IF3_PC_COMP)
237//     comp.io.if2_pc := if2_pc
238//     comp.io.pc     := pc
239//     comp.io.if2_valid := if2_valid
240//     comp.io.res
241//   }
242
243//   val if3_prevHalfNotMetRedirect = if3_pendingPrevHalfInstr && !if3_prevHalfInstrMet && if3_nextValidPCNotEquals(if3_prevHalfInstr.bits.npc)
244//   val if3_predTakenRedirect    = !if3_pendingPrevHalfInstr && if3_bp.taken && if3_nextValidPCNotEquals(if3_bp.target)
245//   val if3_predNotTakenRedirect = !if3_pendingPrevHalfInstr && !if3_bp.taken && if3_nextValidPCNotEquals(if3_snpc)
246//   // when pendingPrevHalfInstr, if3_GHInfo is set to the info of last prev half instr
247//   // val if3_ghInfoNotIdenticalRedirect = !if3_pendingPrevHalfInstr && if3_GHInfo =/= if3_lastGHInfo && enableGhistRepair.B
248
249//   if3_redirect := if3_valid && (
250//                     // prevHalf does not match if3_pc and the next fetch packet is not snpc
251//                     if3_prevHalfNotMetRedirect && HasCExtension.B ||
252//                     // pred taken and next fetch packet is not the predicted target
253//                     if3_predTakenRedirect ||
254//                     // pred not taken and next fetch packet is not snpc
255//                     if3_predNotTakenRedirect
256//                     // GHInfo from last pred does not corresponds with this packet
257//                     // if3_ghInfoNotIdenticalRedirect
258//                   )
259
260//   val if3_target = WireInit(if3_snpc)
261
262//   if3_target := Mux1H(Seq((if3_prevHalfNotMetRedirect -> if3_prevHalfInstr.bits.npc),
263//                           (if3_predTakenRedirect      -> if3_bp.target),
264//                           (if3_predNotTakenRedirect   -> if3_snpc)))
265
266//   npcGen.register(if3_redirect, if3_target, Some("if3_target"))
267
268
269//   //********************** IF4 ****************************//
270//   val ftqEnqBuf_ready = Wire(Bool())
271//   val if4_ftqEnqPtr = Wire(new FtqPtr)
272//   val if4_pd = RegEnable(icache.io.pd_out, if3_fire)
273//   val if4_ipf = RegEnable(icacheResp.ipf || if3_prevHalfInstrMet && if3_prevHalfInstr.bits.ipf, if3_fire)
274//   val if4_acf = RegEnable(icacheResp.acf, if3_fire)
275//   val if4_crossPageIPF = RegEnable(crossPageIPF, if3_fire)
276//   val if4_valid = RegInit(false.B)
277//   val if4_fire = if4_valid && io.fetchPacket.ready && ftqEnqBuf_ready
278//   val if4_pc = RegEnable(if3_pc, if3_fire)
279//   val if4_snpc = RegEnable(if3_snpc, if3_fire)
280//   // This is the real mask given from icache
281//   val if4_mask = RegEnable(icacheResp.mask, if3_fire)
282
283
284//   val if4_predHist = RegEnable(if3_predHist, enable=if3_fire)
285//   // wait until prevHalfInstr written into reg
286//   if4_ready := (io.fetchPacket.ready && !hasPrevHalfInstrReq && ftqEnqBuf_ready || !if4_valid) && GTimer() > 500.U
287//   when (if4_flush) {
288//     if4_valid := false.B
289//   }.elsewhen (if3_fire && !if3_flush) {
290//     if4_valid := Mux(if3_pendingPrevHalfInstr, if3_prevHalfInstrMet, true.B)
291//   }.elsewhen (if4_fire) {
292//     if4_valid := false.B
293//   }
294
295//   val if4_bp = Wire(new BranchPrediction)
296//   if4_bp := bpu.io.out(2)
297
298//   if4_predicted_gh := if4_gh.update(if4_bp.hasNotTakenBrs, if4_bp.takenOnBr)
299
300//   def jal_offset(inst: UInt, rvc: Bool): SInt = {
301//     Mux(rvc,
302//       Cat(inst(12), inst(8), inst(10, 9), inst(6), inst(7), inst(2), inst(11), inst(5, 3), 0.U(1.W)).asSInt(),
303//       Cat(inst(31), inst(19, 12), inst(20), inst(30, 21), 0.U(1.W)).asSInt()
304//     )
305//   }
306//   def br_offset(inst: UInt, rvc: Bool): SInt = {
307//     Mux(rvc,
308//       Cat(inst(12), inst(6, 5), inst(2), inst(11, 10), inst(4, 3), 0.U(1.W)).asSInt,
309//       Cat(inst(31), inst(7), inst(30, 25), inst(11, 8), 0.U(1.W)).asSInt()
310//     )
311//   }
312//   val if4_instrs = if4_pd.instrs
313//   val if4_jals = if4_bp.jalMask
314//   val if4_jal_tgts = VecInit((0 until PredictWidth).map(i => (if4_pd.pc(i).asSInt + jal_offset(if4_instrs(i), if4_pd.pd(i).isRVC)).asUInt))
315//   val if4_brs = if4_bp.brMask
316//   val if4_br_tgts = VecInit((0 until PredictWidth).map(i => (if4_pd.pc(i).asSInt + br_offset(if4_instrs(i), if4_pd.pd(i).isRVC)).asUInt))
317//   (0 until PredictWidth).foreach {i =>
318//     when (if4_jals(i)) {
319//       if4_bp.targets(i) := if4_jal_tgts(i)
320//     }.elsewhen (if4_brs(i)) {
321//       if4_bp.targets(i) := if4_br_tgts(i)
322//     }
323//   }
324
325//   // we need this to tell BPU the prediction of prev half
326//   // because the prediction is with the start of each inst
327//   val if4_prevHalfInstr = RegInit(0.U.asTypeOf(ValidUndirectioned(new PrevHalfInstr)))
328//   val if4_pendingPrevHalfInstr = if4_prevHalfInstr.valid && HasCExtension.B
329//   val if4_prevHalfInstrMet = if4_pendingPrevHalfInstr && if4_valid
330//   val if4_prevHalfConsumed = if4_prevHalfInstrMet && if4_fire
331//   val if4_prevHalfFlush = if4_flush
332
333//   when (if4_prevHalfFlush) {
334//     if4_prevHalfInstr.valid := false.B
335//   }.elsewhen (if3_prevHalfConsumed) {
336//     if4_prevHalfInstr.valid := if3_prevHalfInstr.valid
337//   }.elsewhen (if4_prevHalfConsumed) {
338//     if4_prevHalfInstr.valid := false.B
339//   }
340
341//   when (if3_prevHalfConsumed) {
342//     if4_prevHalfInstr.bits := if3_prevHalfInstr.bits
343//   }
344
345//   prevHalfInstrReq.valid := if4_fire && if4_bp.saveHalfRVI && HasCExtension.B
346
347//   // // this is result of the last half RVI
348//   prevHalfInstrReq.bits.pc := if4_pd.pc(PredictWidth-1)
349//   prevHalfInstrReq.bits.npc := snpc(if4_pc)
350//   prevHalfInstrReq.bits.instr := if4_pd.instrs(PredictWidth-1)(15, 0)
351//   prevHalfInstrReq.bits.ipf := if4_ipf
352
353//   class IF4_PC_COMP extends XSModule {
354//     val io = IO(new Bundle {
355//       val if2_pc = Input(UInt(VAddrBits.W))
356//       val if3_pc = Input(UInt(VAddrBits.W))
357//       val pc     = Input(UInt(VAddrBits.W))
358//       val if2_valid = Input(Bool())
359//       val if3_valid = Input(Bool())
360//       val res = Output(Bool())
361//     })
362//     io.res := io.if3_valid  && io.if3_pc =/= io.pc ||
363//               !io.if3_valid && (io.if2_valid && io.if2_pc =/= io.pc) ||
364//               !io.if3_valid && !io.if2_valid
365//   }
366//   def if4_nextValidPCNotEquals(pc: UInt) = {
367//     val comp = Module(new IF4_PC_COMP)
368//     comp.io.if2_pc := if2_pc
369//     comp.io.if3_pc := if3_pc
370//     comp.io.pc     := pc
371//     comp.io.if2_valid := if2_valid
372//     comp.io.if3_valid := if3_valid
373//     comp.io.res
374//   }
375
376//   val if4_prevHalfNextNotMet = hasPrevHalfInstrReq && if4_nextValidPCNotEquals(prevHalfInstrReq.bits.pc+2.U)
377//   val if4_predTakenRedirect = if4_bp.taken && if4_nextValidPCNotEquals(if4_bp.target)
378//   val if4_predNotTakenRedirect = !if4_bp.taken && if4_nextValidPCNotEquals(if4_snpc)
379//   // val if4_ghInfoNotIdenticalRedirect = if4_GHInfo =/= if4_lastGHInfo && enableGhistRepair.B
380
381//   if4_redirect := if4_valid && (
382//                     // when if4 has a lastHalfRVI, but the next fetch packet is not snpc
383//                     // if4_prevHalfNextNotMet ||
384//                     // when if4 preds taken, but the pc of next fetch packet is not the target
385//                     if4_predTakenRedirect ||
386//                     // when if4 preds not taken, but the pc of next fetch packet is not snpc
387//                     if4_predNotTakenRedirect
388//                     // GHInfo from last pred does not corresponds with this packet
389//                     // if4_ghInfoNotIdenticalRedirect
390//                   )
391
392//   val if4_target = WireInit(if4_snpc)
393
394//   if4_target := Mux(if4_bp.taken, if4_bp.target, if4_snpc)
395
396//   npcGen.register(if4_redirect, if4_target, Some("if4_target"))
397
398//   when (if4_fire) {
399//     final_gh := if4_predicted_gh
400//   }
401//   if4_gh := final_gh
402//   if3_gh := Mux(if4_valid, if4_predicted_gh, if4_gh)
403//   if2_gh := Mux(if3_valid && !if3_flush, if3_predicted_gh, if3_gh)
404//   if1_gh := Mux(if2_valid && !if2_flush, if2_predicted_gh, if2_gh)
405
406//   // ***************** Ftq enq buffer ********************
407//   val toFtqBuf = Wire(new FtqEntry)
408//   val ftqEnqBuf = RegEnable(toFtqBuf, enable=if4_fire)
409//   val ftqEnqBuf_valid = RegInit(false.B)
410//   val ftqLeftOne = WireInit(false.B) // TODO: to be replaced
411//   ftqEnqBuf_ready := io.toFtq.ready && !(io.ftqLeftOne && ftqEnqBuf_valid)
412//   if4_ftqEnqPtr := Mux(ftqEnqBuf_valid, io.ftqEnqPtr+1.U, io.ftqEnqPtr)
413//   when (io.redirect.valid)  { ftqEnqBuf_valid := false.B }
414//   .elsewhen (if4_fire)      { ftqEnqBuf_valid := true.B }
415//   .elsewhen (io.toFtq.fire) { ftqEnqBuf_valid := false.B }
416
417//   io.toFtq.valid := ftqEnqBuf_valid
418//   io.toFtq.bits  := ftqEnqBuf
419
420//   toFtqBuf := DontCare
421//   toFtqBuf.ftqPC    := if4_pc
422//   toFtqBuf.lastPacketPC.valid := if4_pendingPrevHalfInstr
423//   toFtqBuf.lastPacketPC.bits  := if4_prevHalfInstr.bits.pc
424
425//   toFtqBuf.hist     := final_gh
426//   toFtqBuf.predHist := if4_predHist.asTypeOf(new GlobalHistory)
427//   toFtqBuf.rasSp    := bpu.io.brInfo.rasSp
428//   toFtqBuf.rasTop   := bpu.io.brInfo.rasTop
429//   toFtqBuf.specCnt  := bpu.io.brInfo.specCnt
430//   toFtqBuf.metas    := bpu.io.brInfo.metas
431
432//   // For perf counters
433//   toFtqBuf.pd    := if4_pd.pd
434
435
436//   val if4_jmpIdx = WireInit(if4_bp.jmpIdx)
437//   val if4_taken = WireInit(if4_bp.taken)
438//   val if4_real_valids = if4_pd.mask &
439//     (Fill(PredictWidth, !if4_taken) |
440//       (Fill(PredictWidth, 1.U(1.W)) >> (~if4_jmpIdx)))
441
442//   val cfiIsCall = if4_pd.pd(if4_jmpIdx).isCall
443//   val cfiIsRet  = if4_pd.pd(if4_jmpIdx).isRet
444//   val cfiIsRVC  = if4_pd.pd(if4_jmpIdx).isRVC
445//   val cfiIsJalr = if4_pd.pd(if4_jmpIdx).isJalr
446//   toFtqBuf.cfiIsCall := cfiIsCall
447//   toFtqBuf.cfiIsRet  := cfiIsRet
448//   toFtqBuf.cfiIsJalr := cfiIsJalr
449//   toFtqBuf.cfiIsRVC  := cfiIsRVC
450//   toFtqBuf.cfiIndex.valid := if4_taken
451//   toFtqBuf.cfiIndex.bits  := if4_jmpIdx
452
453//   toFtqBuf.br_mask   := if4_bp.brMask.asTypeOf(Vec(PredictWidth, Bool()))
454//   toFtqBuf.rvc_mask  := VecInit(if4_pd.pd.map(_.isRVC))
455//   toFtqBuf.valids    := if4_real_valids.asTypeOf(Vec(PredictWidth, Bool()))
456//   toFtqBuf.target := Mux(if4_taken, if4_target, if4_snpc)
457
458
459
460//   val r = io.redirect
461//   val cfiUpdate = io.redirect.bits.cfiUpdate
462//   when (r.valid) {
463//     val isMisPred = r.bits.level === 0.U
464//     val b = cfiUpdate
465//     val oldGh = b.hist
466//     val sawNTBr = b.sawNotTakenBranch
467//     val isBr = b.pd.isBr
468//     val taken = Mux(isMisPred, b.taken, b.predTaken)
469//     val updatedGh = oldGh.update(sawNTBr || isBr, isBr && taken)
470//     final_gh := updatedGh
471//     if1_gh := updatedGh
472//   }
473
474//   npcGen.register(io.redirect.valid, io.redirect.bits.cfiUpdate.target, Some("backend_redirect"))
475//   npcGen.register(RegNext(reset.asBool) && !reset.asBool, resetVector.U(VAddrBits.W), Some("reset_vector"))
476
477//   if1_npc := npcGen()
478
479
480//   icache.io.req.valid := if1_fire
481//   icache.io.resp.ready := if4_ready
482//   icache.io.req.bits.addr := if1_npc
483//   icache.io.req.bits.mask := mask(if1_npc)
484//   icache.io.flush := Cat(if3_flush, if2_flush)
485//   icache.io.mem_grant <> io.icacheMemGrant
486//   icache.io.fencei := io.fencei
487//   icache.io.prev.valid := if3_prevHalfInstrMet
488//   icache.io.prev.bits := if3_prevHalfInstr.bits.instr
489//   icache.io.prev_ipf := if3_prevHalfInstr.bits.ipf
490//   icache.io.prev_pc := if3_prevHalfInstr.bits.pc
491//   icache.io.mmio_acquire <> io.mmio_acquire
492//   icache.io.mmio_grant <> io.mmio_grant
493//   icache.io.mmio_flush <> io.mmio_flush
494//   io.icacheMemAcq <> icache.io.mem_acquire
495//   io.l1plusFlush := icache.io.l1plusflush
496//   io.prefetchTrainReq := icache.io.prefetchTrainReq
497//   io.error <> icache.io.error
498
499//   bpu.io.ctrl := RegNext(io.bp_ctrl)
500//   bpu.io.commit <> io.commitUpdate
501//   bpu.io.redirect <> io.redirect
502
503//   bpu.io.inFire(0) := if1_fire
504//   bpu.io.inFire(1) := if2_fire
505//   bpu.io.inFire(2) := if3_fire
506//   bpu.io.inFire(3) := if4_fire
507//   bpu.io.in.pc := if1_npc
508//   bpu.io.in.hist := if1_gh.asUInt
509//   bpu.io.in.inMask := mask(if1_npc)
510//   bpu.io.predecode.mask := if4_pd.mask
511//   bpu.io.predecode.lastHalf := if4_pd.lastHalf
512//   bpu.io.predecode.pd := if4_pd.pd
513//   bpu.io.predecode.hasLastHalfRVI := if4_prevHalfInstrMet
514
515
516//   when (if3_prevHalfInstrMet && icacheResp.ipf && !if3_prevHalfInstr.bits.ipf) {
517//     crossPageIPF := true.B // higher 16 bits page fault
518//   }
519
520//   val fetchPacketValid = if4_valid && !io.redirect.valid && ftqEnqBuf_ready
521//   val fetchPacketWire = Wire(new FetchPacket)
522
523//   fetchPacketWire.mask := if4_real_valids
524//   //RVC expand
525//   val expandedInstrs = Wire(Vec(PredictWidth, UInt(32.W)))
526//   for(i <- 0 until PredictWidth){
527//       val expander = Module(new RVCExpander)
528//       expander.io.in := if4_pd.instrs(i)
529//       expandedInstrs(i) := expander.io.out.bits
530//   }
531//   fetchPacketWire.instrs := expandedInstrs
532
533//   fetchPacketWire.pc := if4_pd.pc
534//   fetchPacketWire.foldpc := if4_pd.pc.map(i => XORFold(i(VAddrBits-1,1), MemPredPCWidth))
535
536//   fetchPacketWire.pdmask := if4_pd.mask
537//   fetchPacketWire.pd := if4_pd.pd
538//   fetchPacketWire.ipf := if4_ipf
539//   fetchPacketWire.acf := if4_acf
540//   fetchPacketWire.crossPageIPFFix := if4_crossPageIPF
541//   fetchPacketWire.ftqPtr := if4_ftqEnqPtr
542
543//   // predTaken Vec
544//   fetchPacketWire.pred_taken := if4_bp.takens
545
546//   io.fetchPacket.bits := fetchPacketWire
547//   io.fetchPacket.valid := fetchPacketValid
548
549//   if (!env.FPGAPlatform && env.EnablePerfDebug) {
550//     val predictor_s3 = RegEnable(Mux(if3_redirect, 1.U(log2Up(4).W), 0.U(log2Up(4).W)), if3_fire)
551//     val predictor_s4 = Mux(if4_redirect, 2.U, predictor_s3)
552//     val predictor = predictor_s4
553//     toFtqBuf.metas.map(_.predictor := predictor)
554
555//     toFtqBuf.metas.zipWithIndex.foreach{ case(x,i) =>
556//       x.predictor := predictor
557
558//       x.ubtbAns := bpu.io.brInfo.metas(i).ubtbAns
559//       x.btbAns := bpu.io.brInfo.metas(i).btbAns
560//       x.tageAns := bpu.io.brInfo.metas(i).tageAns
561//       x.rasAns := bpu.io.brInfo.metas(i).rasAns // Is this right?
562//       x.loopAns := bpu.io.brInfo.metas(i).loopAns
563//     }
564//   }
565
566//   // TODO: perfs
567//   // frontend redirect from each stage
568//   XSPerfAccumulate("if2_redirect", if2_valid && if2_bp.taken && !if2_flush)
569//   XSPerfAccumulate("if2_redirect_fired", if2_fire && if2_bp.taken && !if2_flush)
570//   XSPerfAccumulate("if3_redirect", if3_valid && if3_redirect && !if3_flush)
571//   XSPerfAccumulate("if3_redirect_fired", if3_fire && if3_redirect && !if3_flush)
572//   XSPerfAccumulate("if4_redirect", if4_valid && if4_redirect && !if4_flush)
573//   XSPerfAccumulate("if4_redirect_fired", if4_fire && if4_redirect && !if4_flush)
574
575//   XSPerfAccumulate("if1_total_stall", !if2_allReady && if1_valid)
576//   XSPerfAccumulate("if1_stall_from_icache_req", !icache.io.req.ready && if1_valid)
577//   XSPerfAccumulate("if1_stall_from_if2", !if2_ready && if1_valid)
578//   XSPerfAccumulate("if1_stall_from_bpu", !bpu.io.in_ready && if1_valid)
579//   XSPerfAccumulate("itlb_stall", if2_valid && if3_ready && !icache.io.tlb.resp.valid)
580//   XSPerfAccumulate("icache_resp_stall", if3_valid && if4_ready && !icache.io.resp.valid)
581//   XSPerfAccumulate("if4_stall", if4_valid && !if4_fire)
582//   XSPerfAccumulate("if4_stall_ibuffer", if4_valid && !io.fetchPacket.ready && ftqEnqBuf_ready)
583//   XSPerfAccumulate("if4_stall_ftq", if4_valid && io.fetchPacket.ready && !ftqEnqBuf_ready)
584
585//   XSPerfAccumulate("if3_prevHalfConsumed", if3_prevHalfConsumed)
586//   XSPerfAccumulate("if4_prevHalfConsumed", if4_prevHalfConsumed)
587
588
589//   // debug info
590//   if (IFUDebug) {
591//     XSDebug(RegNext(reset.asBool) && !reset.asBool, "Reseting...\n")
592//     XSDebug(icache.io.flush(0).asBool, "Flush icache stage2...\n")
593//     XSDebug(icache.io.flush(1).asBool, "Flush icache stage3...\n")
594//     XSDebug(io.redirect.valid, p"Redirect from backend! target=${Hexadecimal(io.redirect.bits.cfiUpdate.target)}\n")
595
596//     XSDebug("[IF1] v=%d      fire=%d             flush=%d pc=%x mask=%b\n", if1_valid, if1_fire, if1_flush, if1_npc, mask(if1_npc))
597//     XSDebug("[IF2] v=%d r=%d fire=%d redirect=%d flush=%d pc=%x snpc=%x\n", if2_valid, if2_ready, if2_fire, if2_redirect, if2_flush, if2_pc, if2_snpc)
598//     XSDebug("[IF3] v=%d r=%d fire=%d redirect=%d flush=%d pc=%x crossPageIPF=%d sawNTBrs=%d\n", if3_valid, if3_ready, if3_fire, if3_redirect, if3_flush, if3_pc, crossPageIPF, if3_bp.hasNotTakenBrs)
599//     XSDebug("[IF4] v=%d r=%d fire=%d redirect=%d flush=%d pc=%x crossPageIPF=%d sawNTBrs=%d\n", if4_valid, if4_ready, if4_fire, if4_redirect, if4_flush, if4_pc, if4_crossPageIPF, if4_bp.hasNotTakenBrs)
600//     XSDebug("[IF1][icacheReq] v=%d r=%d addr=%x\n", icache.io.req.valid, icache.io.req.ready, icache.io.req.bits.addr)
601//     XSDebug("[IF1][ghr] hist=%b\n", if1_gh.asUInt)
602
603//     XSDebug("[IF2][bp] taken=%d jmpIdx=%d hasNTBrs=%d target=%x saveHalfRVI=%d\n\n", if2_bp.taken, if2_bp.jmpIdx, if2_bp.hasNotTakenBrs, if2_bp.target, if2_bp.saveHalfRVI)
604//     if2_gh.debug("if2")
605
606//     XSDebug("[IF3][icacheResp] v=%d r=%d pc=%x mask=%b\n", icache.io.resp.valid, icache.io.resp.ready, icache.io.resp.bits.pc, icache.io.resp.bits.mask)
607//     XSDebug("[IF3][bp] taken=%d jmpIdx=%d hasNTBrs=%d target=%x saveHalfRVI=%d\n", if3_bp.taken, if3_bp.jmpIdx, if3_bp.hasNotTakenBrs, if3_bp.target, if3_bp.saveHalfRVI)
608//     XSDebug("[IF3][redirect]: v=%d, prevNMet=%d, predT=%d, predNT=%d\n", if3_redirect, if3_prevHalfNotMetRedirect, if3_predTakenRedirect, if3_predNotTakenRedirect)
609//     // XSDebug("[IF3][prevHalfInstr] v=%d redirect=%d fetchpc=%x idx=%d tgt=%x taken=%d instr=%x\n\n",
610//     //   prev_half_valid, prev_half_redirect, prev_half_fetchpc, prev_half_idx, prev_half_tgt, prev_half_taken, prev_half_instr)
611//     XSDebug("[IF3][if3_prevHalfInstr] v=%d pc=%x npc=%x  instr=%x ipf=%d\n\n",
612//     if3_prevHalfInstr.valid, if3_prevHalfInstr.bits.pc, if3_prevHalfInstr.bits.npc, if3_prevHalfInstr.bits.instr, if3_prevHalfInstr.bits.ipf)
613//     if3_gh.debug("if3")
614
615//     XSDebug("[IF4][predecode] mask=%b\n", if4_pd.mask)
616//     XSDebug("[IF4][snpc]: %x, realMask=%b\n", if4_snpc, if4_mask)
617//     XSDebug("[IF4][bp] taken=%d jmpIdx=%d hasNTBrs=%d target=%x saveHalfRVI=%d\n", if4_bp.taken, if4_bp.jmpIdx, if4_bp.hasNotTakenBrs, if4_bp.target, if4_bp.saveHalfRVI)
618//     XSDebug("[IF4][redirect]: v=%d, prevNotMet=%d, predT=%d, predNT=%d\n", if4_redirect, if4_prevHalfNextNotMet, if4_predTakenRedirect, if4_predNotTakenRedirect)
619//     XSDebug(if4_pd.pd(if4_bp.jmpIdx).isJal && if4_bp.taken, "[IF4] cfi is jal!  instr=%x target=%x\n", if4_instrs(if4_bp.jmpIdx), if4_jal_tgts(if4_bp.jmpIdx))
620//     XSDebug("[IF4][ prevHalfInstrReq] v=%d pc=%x npc=%x instr=%x ipf=%d\n",
621//       prevHalfInstrReq.valid, prevHalfInstrReq.bits.pc, prevHalfInstrReq.bits.npc, prevHalfInstrReq.bits.instr, prevHalfInstrReq.bits.ipf)
622//     XSDebug("[IF4][if4_prevHalfInstr] v=%d pc=%x npc=%x instr=%x ipf=%d\n",
623//       if4_prevHalfInstr.valid, if4_prevHalfInstr.bits.pc, if4_prevHalfInstr.bits.npc, if4_prevHalfInstr.bits.instr, if4_prevHalfInstr.bits.ipf)
624//     if4_gh.debug("if4")
625//     XSDebug(io.fetchPacket.fire(), "[IF4][fetchPacket] v=%d r=%d mask=%b ipf=%d acf=%d crossPageIPF=%d\n",
626//       io.fetchPacket.valid, io.fetchPacket.ready, io.fetchPacket.bits.mask, io.fetchPacket.bits.ipf, io.fetchPacket.bits.acf, io.fetchPacket.bits.crossPageIPFFix)
627//     for (i <- 0 until PredictWidth) {
628//       XSDebug(io.fetchPacket.fire(), "[IF4][fetchPacket] %b %x pc=%x pd: rvc=%d brType=%b call=%d ret=%d\n",
629//         io.fetchPacket.bits.mask(i),
630//         io.fetchPacket.bits.instrs(i),
631//         io.fetchPacket.bits.pc(i),
632//         io.fetchPacket.bits.pd(i).isRVC,
633//         io.fetchPacket.bits.pd(i).brType,
634//         io.fetchPacket.bits.pd(i).isCall,
635//         io.fetchPacket.bits.pd(i).isRet
636//       )
637//     }
638//     val b = ftqEnqBuf
639//     XSDebug("[FtqEnqBuf] v=%d r=%d pc=%x cfiIndex(%d)=%d cfiIsCall=%d cfiIsRet=%d cfiIsJalr=%d cfiIsRVC=%d\n",
640//       ftqEnqBuf_valid, ftqEnqBuf_ready, b.ftqPC, b.cfiIndex.valid, b.cfiIndex.bits, b.cfiIsCall, b.cfiIsRet, b.cfiIsJalr, b.cfiIsRVC)
641//     XSDebug("[FtqEnqBuf] valids=%b br_mask=%b rvc_mask=%b hist=%x predHist=%x rasSp=%d rasTopAddr=%x rasTopCtr=%d\n",
642//       b.valids.asUInt, b.br_mask.asUInt, b.rvc_mask.asUInt, b.hist.asUInt, b.predHist.asUInt, b.rasSp, b.rasTop.retAddr, b.rasTop.ctr)
643//     XSDebug("[ToFTQ] v=%d r=%d leftOne=%d ptr=%d\n", io.toFtq.valid, io.toFtq.ready, io.ftqLeftOne, io.ftqEnqPtr.value)
644//   }
645
646// }
647