xref: /XiangShan/src/main/scala/xiangshan/frontend/IFU.scala (revision 89231490c9bc89765243e99cd5ea5fabae300c07)
1package xiangshan.frontend
2
3import chisel3._
4import chisel3.util._
5import device.RAMHelper
6import xiangshan._
7import utils._
8
9trait HasIFUConst { this: XSModule =>
10  val resetVector = 0x80000000L//TODO: set reset vec
11  val groupAlign = log2Up(FetchWidth * 4 * 2)
12  def groupPC(pc: UInt): UInt = Cat(pc(VAddrBits-1, groupAlign), 0.U(groupAlign.W))
13  // each 1 bit in mask stands for 2 Bytes
14  def mask(pc: UInt): UInt = (Fill(PredictWidth * 2, 1.U(1.W)) >> pc(groupAlign - 1, 1))(PredictWidth - 1, 0)
15  def snpc(pc: UInt): UInt = pc + (PopCount(mask(pc)) << 1)
16
17  val IFUDebug = false
18}
19
20class IFUIO extends XSBundle
21{
22  val fetchPacket = DecoupledIO(new FetchPacket)
23  val redirect = Flipped(ValidIO(new Redirect))
24  val outOfOrderBrInfo = Flipped(ValidIO(new BranchUpdateInfo))
25  val inOrderBrInfo = Flipped(ValidIO(new BranchUpdateInfo))
26  val icacheReq = DecoupledIO(new FakeIcacheReq)
27  val icacheResp = Flipped(DecoupledIO(new FakeIcacheResp))
28  val icacheFlush = Output(UInt(2.W))
29}
30
31
32class IFU extends XSModule with HasIFUConst
33{
34  val io = IO(new IFUIO)
35  val bpu = BPU(EnableBPU)
36  val pd = Module(new PreDecode)
37
38  val if2_redirect, if3_redirect, if4_redirect = WireInit(false.B)
39  val if1_flush, if2_flush, if3_flush, if4_flush = WireInit(false.B)
40
41  if4_flush := io.redirect.valid
42  if3_flush := if4_flush || if4_redirect
43  if2_flush := if3_flush || if3_redirect
44  if1_flush := if2_flush || if2_redirect
45
46  //********************** IF1 ****************************//
47  val if1_valid = !reset.asBool
48  val if1_npc = WireInit(0.U(VAddrBits.W))
49  val if2_ready = WireInit(false.B)
50  val if1_fire = if1_valid && (if2_ready || if1_flush) && io.icacheReq.ready
51
52  // val extHist = VecInit(Fill(ExtHistoryLength, RegInit(0.U(1.W))))
53  val extHist = RegInit(VecInit(Seq.fill(ExtHistoryLength)(0.U(1.W))))
54  val headPtr = RegInit(0.U(log2Up(ExtHistoryLength).W))
55  val shiftPtr = WireInit(false.B)
56  val newPtr = Wire(UInt(log2Up(ExtHistoryLength).W))
57  val ptr = Mux(shiftPtr, newPtr, headPtr)
58  when (shiftPtr) { headPtr := newPtr }
59  val hist = Wire(Vec(HistoryLength, UInt(1.W)))
60  for (i <- 0 until HistoryLength) {
61    hist(i) := extHist(ptr + i.U)
62  }
63
64  newPtr := headPtr
65  shiftPtr := false.B
66
67  //********************** IF2 ****************************//
68  val if2_valid = RegEnable(next = if1_valid, init = false.B, enable = if1_fire)
69  val if3_ready = WireInit(false.B)
70  val if2_fire = if2_valid && if3_ready && !if2_flush
71  val if2_pc = RegEnable(next = if1_npc, init = resetVector.U, enable = if1_fire)
72  val if2_snpc = snpc(if2_pc)
73  val if2_histPtr = RegEnable(ptr, if1_fire)
74  if2_ready := if2_fire || !if2_valid || if2_flush
75  when (if2_flush) { if2_valid := if1_fire }
76  .elsewhen (if1_fire) { if2_valid := if1_valid }
77  .elsewhen (if2_fire) { if2_valid := false.B }
78
79  when (RegNext(reset.asBool) && !reset.asBool) {
80    if1_npc := resetVector.U(VAddrBits.W)
81  }.elsewhen (if2_fire) {
82    if1_npc := if2_snpc
83  }.otherwise {
84    if1_npc := RegNext(if1_npc)
85  }
86
87  val if2_bp = bpu.io.out(0).bits
88  if2_redirect := if2_fire && bpu.io.out(0).valid && if2_bp.redirect// && !if2_bp.saveHalfRVI
89  when (if2_redirect) {
90    if1_npc := if2_bp.target
91  }
92
93  when (if2_fire && (if2_bp.takenOnBr || if2_bp.hasNotTakenBrs)) {
94    shiftPtr := true.B
95    newPtr := headPtr - 1.U
96    hist(0) := if2_bp.takenOnBr.asUInt
97    extHist(newPtr) := if2_bp.takenOnBr.asUInt
98  }
99
100  //********************** IF3 ****************************//
101  val if3_valid = RegEnable(next = if2_valid, init = false.B, enable = if2_fire)
102  val if4_ready = WireInit(false.B)
103  val if3_fire = if3_valid && if4_ready && io.icacheResp.valid && !if3_flush
104  val if3_pc = RegEnable(if2_pc, if2_fire)
105  val if3_histPtr = RegEnable(if2_histPtr, if2_fire)
106  if3_ready := if3_fire || !if3_valid || if3_flush
107  when (if3_flush) { if3_valid := false.B }
108  .elsewhen (if2_fire) { if3_valid := if2_valid }
109  .elsewhen (if3_fire) { if3_valid := false.B }
110
111  val if3_bp = bpu.io.out(1).bits
112
113  class PrevHalfInstr extends Bundle {
114    val valid = Bool()
115    val taken = Bool()
116    val fetchpc = UInt(VAddrBits.W) // only for debug
117    val idx = UInt(VAddrBits.W) // only for debug
118    val pc = UInt(VAddrBits.W)
119    val target = UInt(VAddrBits.W)
120    val instr = UInt(16.W)
121    val takenOnBr = Bool()
122  }
123
124  val if3_prevHalfInstr = RegInit(0.U.asTypeOf(new PrevHalfInstr))
125  val if4_prevHalfInstr = Wire(new PrevHalfInstr)
126  when (if4_prevHalfInstr.valid) {
127    if3_prevHalfInstr := if4_prevHalfInstr
128  }
129  val prevHalfInstr = Mux(if4_prevHalfInstr.valid, if4_prevHalfInstr, if3_prevHalfInstr)
130
131  val if3_hasPrevHalfInstr = prevHalfInstr.valid && (prevHalfInstr.pc + 2.U) === if3_pc
132  if3_redirect := if3_fire && bpu.io.out(1).valid && (if3_hasPrevHalfInstr && prevHalfInstr.taken || if3_bp.redirect/* && !if3_bp.saveHalfRVI*/ )
133  when (if3_redirect) {
134    if1_npc := Mux(if3_hasPrevHalfInstr && prevHalfInstr.taken, prevHalfInstr.target, if3_bp.target)
135  }
136
137  when (if3_fire && if3_redirect) {
138    shiftPtr := true.B
139    newPtr := Mux(if3_hasPrevHalfInstr && prevHalfInstr.takenOnBr || if3_bp.takenOnBr || if3_bp.hasNotTakenBrs, if3_histPtr - 1.U, if3_histPtr)
140    hist(0) := Mux(if3_hasPrevHalfInstr && prevHalfInstr.takenOnBr || if3_bp.takenOnBr || if3_bp.hasNotTakenBrs,
141      (if3_hasPrevHalfInstr && prevHalfInstr.takenOnBr || if3_bp.takenOnBr).asUInt,
142      extHist(if3_histPtr))
143    extHist(newPtr) := Mux(if3_hasPrevHalfInstr && prevHalfInstr.takenOnBr || if3_bp.takenOnBr || if3_bp.hasNotTakenBrs,
144      (if3_hasPrevHalfInstr && prevHalfInstr.takenOnBr || if3_bp.takenOnBr).asUInt,
145      extHist(if3_histPtr))
146  }
147
148
149
150  // val prev_half_valid = RegInit(false.B)
151  // val prev_half_redirect = RegInit(false.B)
152  // val prev_half_fetchpc = Reg(UInt(VAddrBits.W))
153  // val prev_half_idx = Reg(UInt(log2Up(PredictWidth).W))
154  // val prev_half_tgt = Reg(UInt(VAddrBits.W))
155  // val prev_half_taken = RegInit(false.B)
156  // val prev_half_instr = Reg(UInt(16.W))
157  // when (if3_flush) {
158  //   prev_half_valid := false.B
159  //   prev_half_redirect := false.B
160  // }.elsewhen (if3_fire && if3_bp.saveHalfRVI) {
161  //   prev_half_valid := true.B
162  //   prev_half_redirect := if3_bp.redirect && bpu.io.out(1).valid
163  //   prev_half_fetchpc := if3_pc
164  //   val idx = Mux(if3_bp.redirect && bpu.io.out(1).valid, if3_bp.jmpIdx, PopCount(mask(if3_pc)) - 1.U)
165  //   prev_half_idx := idx
166  //   prev_half_tgt := if3_bp.target
167  //   prev_half_taken := if3_bp.taken
168  //   prev_half_instr := pd.io.out.instrs(idx)(15, 0)
169  // }.elsewhen (if3_fire) {
170  //   prev_half_valid := false.B
171  //   prev_half_redirect := false.B
172  // }
173
174  // when (bpu.io.out(1).valid && if3_fire) {
175  //   when (prev_half_valid && prev_half_taken) {
176  //     if3_redirect := true.B
177  //     if1_npc := prev_half_tgt
178  //     shiftPtr := true.B
179  //     newPtr := if3_histPtr - 1.U
180  //     hist(0) := 1.U
181  //     extHist(newPtr) := 1.U
182  //   }.elsewhen (if3_bp.redirect && !if3_bp.saveHalfRVI) {
183  //     if3_redirect := true.B
184  //     if1_npc := if3_bp.target
185  //     shiftPtr := true.B
186  //     newPtr := Mux(if3_bp.taken || if3_bp.hasNotTakenBrs, if3_histPtr - 1.U, if3_histPtr)
187  //     hist(0) := Mux(if3_bp.taken || if3_bp.hasNotTakenBrs, if3_bp.taken.asUInt, extHist(if3_histPtr))
188  //     extHist(newPtr) := Mux(if3_bp.taken || if3_bp.hasNotTakenBrs, if3_bp.taken.asUInt, extHist(if3_histPtr))
189  //   }.elsewhen (if3_bp.saveHalfRVI) {
190  //     if3_redirect := true.B
191  //     if1_npc := snpc(if3_pc)
192  //     shiftPtr := true.B
193  //     newPtr := Mux(if3_bp.hasNotTakenBrs, if3_histPtr - 1.U, if3_histPtr)
194  //     hist(0) := Mux(if3_bp.hasNotTakenBrs, 0.U, extHist(if3_histPtr))
195  //     extHist(newPtr) := Mux(if3_bp.hasNotTakenBrs, 0.U, extHist(if3_histPtr))
196  //   }.otherwise {
197  //     if3_redirect := false.B
198  //   }
199  // }.otherwise {
200  //   if3_redirect := false.B
201  // }
202
203
204  //********************** IF4 ****************************//
205  val if4_pd = RegEnable(pd.io.out, if3_fire)
206  val if4_valid = RegInit(false.B)
207  val if4_fire = if4_valid && io.fetchPacket.ready
208  val if4_pc = RegEnable(if3_pc, if3_fire)
209  val if4_histPtr = RegEnable(if3_histPtr, if3_fire)
210  if4_ready := (if4_fire || !if4_valid || if4_flush) && GTimer() > 500.U
211  when (if4_flush)     { if4_valid := false.B }
212  .elsewhen (if3_fire) { if4_valid := if3_valid }
213  .elsewhen(if4_fire)  { if4_valid := false.B }
214
215  val if4_bp = Wire(new BranchPrediction)
216  if4_bp := bpu.io.out(2).bits
217
218  val if4_cfi_jal = if4_pd.instrs(if4_bp.jmpIdx)
219  val if4_cfi_jal_tgt = if4_pd.pc(if4_bp.jmpIdx) + Mux(if4_pd.pd(if4_bp.jmpIdx).isRVC,
220    SignExt(Cat(if4_cfi_jal(12), if4_cfi_jal(8), if4_cfi_jal(10, 9), if4_cfi_jal(6), if4_cfi_jal(7), if4_cfi_jal(2), if4_cfi_jal(11), if4_cfi_jal(5, 3), 0.U(1.W)), XLEN),
221    SignExt(Cat(if4_cfi_jal(31), if4_cfi_jal(19, 12), if4_cfi_jal(20), if4_cfi_jal(30, 21), 0.U(1.W)), XLEN))
222  if4_bp.target := Mux(if4_pd.pd(if4_bp.jmpIdx).isJal && if4_bp.taken, if4_cfi_jal_tgt, bpu.io.out(2).bits.target)
223  if4_bp.redirect := bpu.io.out(2).bits.redirect || if4_pd.pd(if4_bp.jmpIdx).isJal && if4_bp.taken && if4_cfi_jal_tgt =/= bpu.io.out(2).bits.target
224
225  if4_prevHalfInstr := 0.U.asTypeOf(new PrevHalfInstr)
226  when (bpu.io.out(2).valid && if4_fire && if4_bp.saveHalfRVI) {
227    if4_prevHalfInstr.valid := true.B
228    if4_prevHalfInstr.taken := if4_bp.taken
229    if4_prevHalfInstr.takenOnBr := if4_bp.takenOnBr
230    if4_prevHalfInstr.fetchpc := if4_pc
231    if4_prevHalfInstr.idx := PopCount(mask(if4_pc)) - 1.U
232    if4_prevHalfInstr.pc := if4_pd.pc(if4_prevHalfInstr.idx)
233    if4_prevHalfInstr.target := if4_bp.target
234    if4_prevHalfInstr.instr := if4_pd.instrs(if4_prevHalfInstr.idx)(15, 0)
235  }
236
237  when (bpu.io.out(2).valid && if4_fire && if4_bp.redirect) {
238    if4_redirect := true.B
239    shiftPtr := true.B
240    newPtr := Mux(if4_bp.takenOnBr || if4_bp.hasNotTakenBrs, if4_histPtr - 1.U, if4_histPtr)
241    hist(0) := Mux(if4_bp.takenOnBr || if4_bp.hasNotTakenBrs, if4_bp.takenOnBr.asUInt, extHist(if4_histPtr))
242    extHist(newPtr) := Mux(if4_bp.takenOnBr || if4_bp.hasNotTakenBrs, if4_bp.takenOnBr.asUInt, extHist(if4_histPtr))
243    when (if4_bp.saveHalfRVI) {
244      if1_npc := snpc(if4_pc)
245    }.otherwise {
246      if1_npc := if4_bp.target
247    }
248  }.elsewhen (bpu.io.out(2).valid && if4_fire/* && !if4_bp.redirect*/) {
249    when (if4_bp.saveHalfRVI && if4_bp.takenOnBr) {
250      if4_redirect := true.B
251      if1_npc := snpc(if4_pc)
252      shiftPtr := true.B
253      newPtr := if4_histPtr - 1.U
254      hist(0) := 1.U
255      extHist(newPtr) := 1.U
256    }.elsewhen (if4_bp.saveHalfRVI && if4_bp.taken) {
257      if4_redirect := true.B
258      if1_npc := snpc(if4_pc)
259      shiftPtr := true.B
260      newPtr := if4_histPtr
261      hist(0) := extHist(if4_histPtr)
262      extHist(newPtr) := extHist(if4_histPtr)
263    }.otherwise {
264      if4_redirect := false.B
265    }
266  }.otherwise {
267    if4_redirect := false.B
268  }
269
270
271
272  // when (bpu.io.out(2).valid && if4_fire && if4_bp.redirect) {
273  //   when (!if4_bp.saveHalfRVI) {
274  //     if4_redirect := true.B
275  //     // if1_npc := if4_bp.target
276  //     if1_npc := Mux(if4_bp.taken, if4_bp.target, snpc(if4_pc))
277
278  //     shiftPtr := true.B
279  //     newPtr := Mux(if4_bp.taken || if4_bp.hasNotTakenBrs, if4_histPtr - 1.U, if4_histPtr)
280  //     hist(0) := Mux(if4_bp.taken || if4_bp.hasNotTakenBrs, if4_bp.taken.asUInt, extHist(if4_histPtr))
281  //     extHist(newPtr) := Mux(if4_bp.taken || if4_bp.hasNotTakenBrs, if4_bp.taken.asUInt, extHist(if4_histPtr))
282
283  //   }.otherwise {
284  //     if4_redirect := true.B
285  //     if1_npc := snpc(if4_pc)
286
287  //     prev_half_valid := true.B
288  //     prev_half_redirect := true.B
289  //     prev_half_fetchpc := if4_pc
290  //     val idx = PopCount(mask(if4_pc)) - 1.U
291  //     prev_half_idx := idx
292  //     prev_half_tgt := if4_bp.target
293  //     prev_half_taken := if4_bp.taken
294  //     prev_half_instr := if4_pd.instrs(idx)(15, 0)
295
296  //     shiftPtr := true.B
297  //     newPtr := Mux(if4_bp.hasNotTakenBrs, if4_histPtr - 1.U, if4_histPtr)
298  //     hist(0) := Mux(if4_bp.hasNotTakenBrs, 0.U, extHist(if4_histPtr))
299  //     extHist(newPtr) := Mux(if4_bp.hasNotTakenBrs, 0.U, extHist(if4_histPtr))
300  //   }
301  // }.otherwise {
302  //   if4_redirect := false.B
303  // }
304
305  when (io.outOfOrderBrInfo.valid && io.outOfOrderBrInfo.bits.isMisPred) {
306    val b = io.outOfOrderBrInfo.bits
307    val oldPtr = b.brInfo.histPtr
308    shiftPtr := true.B
309    when (!b.pd.isBr && !b.brInfo.sawNotTakenBranch) {
310      // If mispredicted cfi is not a branch,
311      // and there wasn't any not taken branch before it,
312      // we should only recover the pointer to an unshifted state
313      newPtr := oldPtr
314    }.otherwise {
315      newPtr := oldPtr - 1.U
316      hist(0) := b.taken
317      extHist(newPtr) := b.taken
318    }
319  }
320
321  when (io.redirect.valid) {
322    if1_npc := io.redirect.bits.target
323  }
324
325  io.icacheReq.valid := if1_valid && if2_ready
326  io.icacheReq.bits.addr := if1_npc
327  io.icacheResp.ready := if3_ready
328  io.icacheFlush := Cat(if3_flush, if2_flush)
329
330  val inOrderBrHist = Wire(Vec(HistoryLength, UInt(1.W)))
331  (0 until HistoryLength).foreach(i => inOrderBrHist(i) := extHist(i.U + io.inOrderBrInfo.bits.brInfo.histPtr))
332  bpu.io.inOrderBrInfo.valid := io.inOrderBrInfo.valid
333  bpu.io.inOrderBrInfo.bits := BranchUpdateInfoWithHist(io.inOrderBrInfo.bits, inOrderBrHist.asUInt)
334  bpu.io.outOfOrderBrInfo.valid := io.outOfOrderBrInfo.valid
335  bpu.io.outOfOrderBrInfo.bits := BranchUpdateInfoWithHist(io.outOfOrderBrInfo.bits, inOrderBrHist.asUInt) // Dont care about hist
336
337  // bpu.io.flush := Cat(if4_flush, if3_flush, if2_flush)
338  bpu.io.flush := VecInit(if2_flush, if3_flush, if4_flush)
339  bpu.io.in.valid := if1_fire
340  bpu.io.in.bits.pc := if1_npc
341  bpu.io.in.bits.hist := hist.asUInt
342  bpu.io.in.bits.inMask := mask(if1_npc)
343  bpu.io.out(0).ready := if2_fire
344  bpu.io.out(1).ready := if3_fire
345  bpu.io.out(2).ready := if4_fire
346  bpu.io.predecode.valid := if4_valid
347  bpu.io.predecode.bits.mask := if4_pd.mask
348  bpu.io.predecode.bits.pd := if4_pd.pd
349  bpu.io.predecode.bits.isFetchpcEqualFirstpc := if4_pc === if4_pd.pc(0)
350  bpu.io.branchInfo.ready := if4_fire
351
352  pd.io.in := io.icacheResp.bits
353  pd.io.prev.valid := if3_hasPrevHalfInstr
354  pd.io.prev.bits := prevHalfInstr.instr
355
356  io.fetchPacket.valid := if4_valid && !io.redirect.valid
357  io.fetchPacket.bits.instrs := if4_pd.instrs
358  io.fetchPacket.bits.mask := if4_pd.mask & (Fill(PredictWidth, !if4_bp.taken) | (Fill(PredictWidth, 1.U(1.W)) >> (~if4_bp.jmpIdx)))
359  io.fetchPacket.bits.pc := if4_pd.pc
360  (0 until PredictWidth).foreach(i => io.fetchPacket.bits.pnpc(i) := if4_pd.pc(i) + Mux(if4_pd.pd(i).isRVC, 2.U, 4.U))
361  when (if4_bp.taken) {
362    io.fetchPacket.bits.pnpc(if4_bp.jmpIdx) := if4_bp.target
363  }
364  io.fetchPacket.bits.brInfo := bpu.io.branchInfo.bits
365  (0 until PredictWidth).foreach(i => io.fetchPacket.bits.brInfo(i).histPtr := if4_histPtr)
366  io.fetchPacket.bits.pd := if4_pd.pd
367
368  // debug info
369  if (IFUDebug) {
370    XSDebug(RegNext(reset.asBool) && !reset.asBool, "Reseting...\n")
371    XSDebug(io.icacheFlush(0).asBool, "Flush icache stage2...\n")
372    XSDebug(io.icacheFlush(1).asBool, "Flush icache stage3...\n")
373    XSDebug(io.redirect.valid, "Redirect from backend! isExcp=%d isMisPred=%d isReplay=%d pc=%x\n",
374      io.redirect.bits.isException, io.redirect.bits.isMisPred, io.redirect.bits.isReplay, io.redirect.bits.pc)
375    XSDebug(io.redirect.valid, p"Redirect from backend! target=${Hexadecimal(io.redirect.bits.target)} brTag=${io.redirect.bits.brTag}\n")
376
377    XSDebug("[IF1] v=%d     fire=%d            flush=%d pc=%x ptr=%d mask=%b\n", if1_valid, if1_fire, if1_flush, if1_npc, ptr, mask(if1_npc))
378    XSDebug("[IF2] v=%d r=%d fire=%d redirect=%d flush=%d pc=%x ptr=%d snpc=%x\n", if2_valid, if2_ready, if2_fire, if2_redirect, if2_flush, if2_pc, if2_histPtr, if2_snpc)
379    XSDebug("[IF3] v=%d r=%d fire=%d redirect=%d flush=%d pc=%x ptr=%d\n", if3_valid, if3_ready, if3_fire, if3_redirect, if3_flush, if3_pc, if3_histPtr)
380    XSDebug("[IF4] v=%d r=%d fire=%d redirect=%d flush=%d pc=%x ptr=%d\n", if4_valid, if4_ready, if4_fire, if4_redirect, if4_flush, if4_pc, if4_histPtr)
381
382    XSDebug("[IF1][icacheReq] v=%d r=%d addr=%x\n", io.icacheReq.valid, io.icacheReq.ready, io.icacheReq.bits.addr)
383    XSDebug("[IF1][ghr] headPtr=%d shiftPtr=%d newPtr=%d ptr=%d\n", headPtr, shiftPtr, newPtr, ptr)
384    XSDebug("[IF1][ghr] hist=%b\n", hist.asUInt)
385    XSDebug("[IF1][ghr] extHist=%b\n\n", extHist.asUInt)
386
387    XSDebug("[IF2][bp] redirect=%d taken=%d jmpIdx=%d hasNTBrs=%d target=%x saveHalfRVI=%d\n\n", if2_bp.redirect, if2_bp.taken, if2_bp.jmpIdx, if2_bp.hasNotTakenBrs, if2_bp.target, if2_bp.saveHalfRVI)
388
389    XSDebug("[IF3][icacheResp] v=%d r=%d pc=%x mask=%b\n", io.icacheResp.valid, io.icacheResp.ready, io.icacheResp.bits.pc, io.icacheResp.bits.mask)
390    XSDebug("[IF3][bp] redirect=%d taken=%d jmpIdx=%d hasNTBrs=%d target=%x saveHalfRVI=%d\n", if3_bp.redirect, if3_bp.taken, if3_bp.jmpIdx, if3_bp.hasNotTakenBrs, if3_bp.target, if3_bp.saveHalfRVI)
391    // XSDebug("[IF3][prevHalfInstr] v=%d redirect=%d fetchpc=%x idx=%d tgt=%x taken=%d instr=%x\n\n",
392    //   prev_half_valid, prev_half_redirect, prev_half_fetchpc, prev_half_idx, prev_half_tgt, prev_half_taken, prev_half_instr)
393    XSDebug("[IF3][    prevHalfInstr] v=%d taken=%d fetchpc=%x idx=%d pc=%x tgt=%x instr=%x\n",
394      prevHalfInstr.valid, prevHalfInstr.taken, prevHalfInstr.fetchpc, prevHalfInstr.idx, prevHalfInstr.pc, prevHalfInstr.target, prevHalfInstr.instr)
395    XSDebug("[IF3][if3_prevHalfInstr] v=%d taken=%d fetchpc=%x idx=%d pc=%x tgt=%x instr=%x\n\n",
396      if3_prevHalfInstr.valid, if3_prevHalfInstr.taken, if3_prevHalfInstr.fetchpc, if3_prevHalfInstr.idx, if3_prevHalfInstr.pc, if3_prevHalfInstr.target, if3_prevHalfInstr.instr)
397
398
399    XSDebug("[IF4][predecode] mask=%b\n", if4_pd.mask)
400    XSDebug("[IF4][bp] redirect=%d taken=%d jmpIdx=%d hasNTBrs=%d target=%x saveHalfRVI=%d\n", if4_bp.redirect, if4_bp.taken, if4_bp.jmpIdx, if4_bp.hasNotTakenBrs, if4_bp.target, if4_bp.saveHalfRVI)
401    XSDebug(if4_pd.pd(if4_bp.jmpIdx).isJal && if4_bp.taken, "[IF4] cfi is jal!  instr=%x target=%x\n", if4_cfi_jal, if4_cfi_jal_tgt)
402    XSDebug("[IF4][if4_prevHalfInstr] v=%d taken=%d fetchpc=%x idx=%d pc=%x tgt=%x instr=%x\n",
403      if4_prevHalfInstr.valid, if4_prevHalfInstr.taken, if4_prevHalfInstr.fetchpc, if4_prevHalfInstr.idx, if4_prevHalfInstr.pc, if4_prevHalfInstr.target, if4_prevHalfInstr.instr)
404    XSDebug(io.fetchPacket.fire(), "[IF4][fetchPacket] v=%d r=%d mask=%b\n", io.fetchPacket.valid, io.fetchPacket.ready, io.fetchPacket.bits.mask)
405    for (i <- 0 until PredictWidth) {
406      XSDebug(io.fetchPacket.fire(), "[IF4][fetchPacket] %b %x pc=%x pnpc=%x pd: rvc=%d brType=%b call=%d ret=%d\n",
407        io.fetchPacket.bits.mask(i),
408        io.fetchPacket.bits.instrs(i),
409        io.fetchPacket.bits.pc(i),
410        io.fetchPacket.bits.pnpc(i),
411        io.fetchPacket.bits.pd(i).isRVC,
412        io.fetchPacket.bits.pd(i).brType,
413        io.fetchPacket.bits.pd(i).isCall,
414        io.fetchPacket.bits.pd(i).isRet
415      )
416    }
417  }
418}