xref: /XiangShan/src/main/scala/xiangshan/mem/MemCommon.scala (revision 887862dbb8debde8ab099befc426493834a69ee7)
1/***************************************************************************************
2* Copyright (c) 2024 Beijing Institute of Open Source Chip (BOSC)
3* Copyright (c) 2020-2024 Institute of Computing Technology, Chinese Academy of Sciences
4* Copyright (c) 2020-2021 Peng Cheng Laboratory
5*
6* XiangShan is licensed under Mulan PSL v2.
7* You can use this software according to the terms and conditions of the Mulan PSL v2.
8* You may obtain a copy of Mulan PSL v2 at:
9*          http://license.coscl.org.cn/MulanPSL2
10*
11* THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
12* EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
13* MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
14*
15* See the Mulan PSL v2 for more details.
16***************************************************************************************/
17
18package xiangshan.mem
19
20
21import org.chipsalliance.cde.config.Parameters
22import chisel3._
23import chisel3.util._
24import utility._
25import utils._
26import xiangshan._
27import xiangshan.backend.Bundles.{DynInst, MemExuInput}
28import xiangshan.backend.rob.RobPtr
29import xiangshan.cache._
30import xiangshan.backend.fu.FenceToSbuffer
31import xiangshan.cache.wpu.ReplayCarry
32import xiangshan.mem.prefetch.PrefetchReqBundle
33import math._
34
35object genWmask {
36  def apply(addr: UInt, sizeEncode: UInt): UInt = {
37    (LookupTree(sizeEncode, List(
38      "b00".U -> 0x1.U, //0001 << addr(2:0)
39      "b01".U -> 0x3.U, //0011
40      "b10".U -> 0xf.U, //1111
41      "b11".U -> 0xff.U //11111111
42    )) << addr(2, 0)).asUInt
43  }
44}
45
46object genVWmask {
47  def apply(addr: UInt, sizeEncode: UInt): UInt = {
48    (LookupTree(sizeEncode, List(
49      "b00".U -> 0x1.U, //0001 << addr(2:0)
50      "b01".U -> 0x3.U, //0011
51      "b10".U -> 0xf.U, //1111
52      "b11".U -> 0xff.U //11111111
53    )) << addr(3, 0)).asUInt
54  }
55}
56
57object genWdata {
58  def apply(data: UInt, sizeEncode: UInt): UInt = {
59    LookupTree(sizeEncode, List(
60      "b00".U -> Fill(16, data(7, 0)),
61      "b01".U -> Fill(8, data(15, 0)),
62      "b10".U -> Fill(4, data(31, 0)),
63      "b11".U -> Fill(2, data(63,0))
64    ))
65  }
66}
67
68object shiftDataToLow {
69  def apply(addr: UInt,data : UInt): UInt = {
70    Mux(addr(3), (data >> 64).asUInt,data)
71  }
72}
73object shiftMaskToLow {
74  def apply(addr: UInt,mask: UInt): UInt = {
75    Mux(addr(3),(mask >> 8).asUInt,mask)
76  }
77}
78
79class LsPipelineBundle(implicit p: Parameters) extends XSBundle
80  with HasDCacheParameters
81  with HasVLSUParameters {
82  val uop = new DynInst
83  val vaddr = UInt(VAddrBits.W)
84  val paddr = UInt(PAddrBits.W)
85  val gpaddr = UInt(GPAddrBits.W)
86  // val func = UInt(6.W)
87  val mask = UInt((VLEN/8).W)
88  val data = UInt((VLEN+1).W)
89  val wlineflag = Bool() // store write the whole cache line
90
91  val miss = Bool()
92  val tlbMiss = Bool()
93  val ptwBack = Bool()
94  val af = Bool()
95  val mmio = Bool()
96  val atomic = Bool()
97
98  val forwardMask = Vec(VLEN/8, Bool())
99  val forwardData = Vec(VLEN/8, UInt(8.W))
100
101  // prefetch
102  val isPrefetch = Bool()
103  val isHWPrefetch = Bool()
104  def isSWPrefetch = isPrefetch && !isHWPrefetch
105
106  // misalignBuffer
107  val isFrmMisAlignBuf = Bool()
108
109  // vector
110  val isvec = Bool()
111  val isLastElem = Bool()
112  val is128bit = Bool()
113  val uop_unit_stride_fof = Bool()
114  val usSecondInv = Bool()
115  val elemIdx = UInt(elemIdxBits.W)
116  val alignedType = UInt(alignTypeBits.W)
117  val mbIndex = UInt(max(vlmBindexBits, vsmBindexBits).W)
118  // val rob_idx_valid = Vec(2,Bool())
119  // val inner_idx = Vec(2,UInt(3.W))
120  // val rob_idx = Vec(2,new RobPtr)
121  val reg_offset = UInt(vOffsetBits.W)
122  val elemIdxInsideVd = UInt(elemIdxBits.W)
123  // val offset = Vec(2,UInt(4.W))
124  val vecActive = Bool() // 1: vector active element or scala mem operation, 0: vector not active element
125  val is_first_ele = Bool()
126  // val flowPtr = new VlflowPtr() // VLFlowQueue ptr
127  // val sflowPtr = new VsFlowPtr() // VSFlowQueue ptr
128
129  // For debug usage
130  val isFirstIssue = Bool()
131  val hasROBEntry = Bool()
132
133  // For load replay
134  val isLoadReplay = Bool()
135  val isFastPath = Bool()
136  val isFastReplay = Bool()
137  val replayCarry = new ReplayCarry(nWays)
138
139  // For dcache miss load
140  val mshrid = UInt(log2Up(cfg.nMissEntries).W)
141  val handledByMSHR = Bool()
142  val replacementUpdated = Bool()
143  val missDbUpdated = Bool()
144
145  val forward_tlDchannel = Bool()
146  val dcacheRequireReplay = Bool()
147  val delayedLoadError = Bool()
148  val lateKill = Bool()
149  val feedbacked = Bool()
150  val ldCancel = ValidUndirectioned(UInt(log2Ceil(LoadPipelineWidth).W))
151  // loadQueueReplay index.
152  val schedIndex = UInt(log2Up(LoadQueueReplaySize).W)
153}
154
155class LdPrefetchTrainBundle(implicit p: Parameters) extends LsPipelineBundle {
156  val meta_prefetch = UInt(L1PfSourceBits.W)
157  val meta_access = Bool()
158
159  def fromLsPipelineBundle(input: LsPipelineBundle, latch: Boolean = false, enable: Bool = true.B) = {
160    if (latch) vaddr := RegEnable(input.vaddr, enable) else vaddr := input.vaddr
161    if (latch) paddr := RegEnable(input.paddr, enable) else paddr := input.paddr
162    if (latch) gpaddr := RegEnable(input.gpaddr, enable) else gpaddr := input.gpaddr
163    if (latch) mask := RegEnable(input.mask, enable) else mask := input.mask
164    if (latch) data := RegEnable(input.data, enable) else data := input.data
165    if (latch) uop := RegEnable(input.uop, enable) else uop := input.uop
166    if (latch) wlineflag := RegEnable(input.wlineflag, enable) else wlineflag := input.wlineflag
167    if (latch) miss := RegEnable(input.miss, enable) else miss := input.miss
168    if (latch) tlbMiss := RegEnable(input.tlbMiss, enable) else tlbMiss := input.tlbMiss
169    if (latch) ptwBack := RegEnable(input.ptwBack, enable) else ptwBack := input.ptwBack
170    if (latch) af := RegEnable(input.af, enable) else af := input.af
171    if (latch) mmio := RegEnable(input.mmio, enable) else mmio := input.mmio
172    if (latch) forwardMask := RegEnable(input.forwardMask, enable) else forwardMask := input.forwardMask
173    if (latch) forwardData := RegEnable(input.forwardData, enable) else forwardData := input.forwardData
174    if (latch) isPrefetch := RegEnable(input.isPrefetch, enable) else isPrefetch := input.isPrefetch
175    if (latch) isHWPrefetch := RegEnable(input.isHWPrefetch, enable) else isHWPrefetch := input.isHWPrefetch
176    if (latch) isFrmMisAlignBuf := RegEnable(input.isFrmMisAlignBuf, enable) else isFrmMisAlignBuf := input.isFrmMisAlignBuf
177    if (latch) isFirstIssue := RegEnable(input.isFirstIssue, enable) else isFirstIssue := input.isFirstIssue
178    if (latch) hasROBEntry := RegEnable(input.hasROBEntry, enable) else hasROBEntry := input.hasROBEntry
179    if (latch) dcacheRequireReplay := RegEnable(input.dcacheRequireReplay, enable) else dcacheRequireReplay := input.dcacheRequireReplay
180    if (latch) schedIndex := RegEnable(input.schedIndex, enable) else schedIndex := input.schedIndex
181    if (latch) isvec               := RegEnable(input.isvec, enable)               else isvec               := input.isvec
182    if (latch) isLastElem          := RegEnable(input.isLastElem, enable)          else isLastElem          := input.isLastElem
183    if (latch) is128bit            := RegEnable(input.is128bit, enable)            else is128bit            := input.is128bit
184    if (latch) vecActive           := RegEnable(input.vecActive, enable)           else vecActive           := input.vecActive
185    if (latch) is_first_ele        := RegEnable(input.is_first_ele, enable)        else is_first_ele        := input.is_first_ele
186    if (latch) uop_unit_stride_fof := RegEnable(input.uop_unit_stride_fof, enable) else uop_unit_stride_fof := input.uop_unit_stride_fof
187    if (latch) usSecondInv         := RegEnable(input.usSecondInv, enable)         else usSecondInv         := input.usSecondInv
188    if (latch) reg_offset          := RegEnable(input.reg_offset, enable)          else reg_offset          := input.reg_offset
189    if (latch) elemIdx             := RegEnable(input.elemIdx, enable)             else elemIdx             := input.elemIdx
190    if (latch) alignedType         := RegEnable(input.alignedType, enable)         else alignedType         := input.alignedType
191    if (latch) mbIndex             := RegEnable(input.mbIndex, enable)             else mbIndex             := input.mbIndex
192    if (latch) elemIdxInsideVd     := RegEnable(input.elemIdxInsideVd, enable)     else elemIdxInsideVd     := input.elemIdxInsideVd
193    // if (latch) flowPtr             := RegEnable(input.flowPtr, enable)             else flowPtr             := input.flowPtr
194    // if (latch) sflowPtr            := RegEnable(input.sflowPtr, enable)            else sflowPtr            := input.sflowPtr
195
196    meta_prefetch := DontCare
197    meta_access := DontCare
198    forward_tlDchannel := DontCare
199    mshrid := DontCare
200    replayCarry := DontCare
201    atomic := DontCare
202    isLoadReplay := DontCare
203    isFastPath := DontCare
204    isFastReplay := DontCare
205    handledByMSHR := DontCare
206    replacementUpdated := DontCare
207    missDbUpdated := DontCare
208    delayedLoadError := DontCare
209    lateKill := DontCare
210    feedbacked := DontCare
211    ldCancel := DontCare
212  }
213
214  def asPrefetchReqBundle(): PrefetchReqBundle = {
215    val res = Wire(new PrefetchReqBundle)
216    res.vaddr := this.vaddr
217    res.paddr := this.paddr
218    res.pc    := this.uop.pc
219    res.miss  := this.miss
220
221    res
222  }
223}
224
225class StPrefetchTrainBundle(implicit p: Parameters) extends LdPrefetchTrainBundle {}
226
227class LqWriteBundle(implicit p: Parameters) extends LsPipelineBundle {
228  // load inst replay informations
229  val rep_info = new LoadToLsqReplayIO
230  // queue entry data, except flag bits, will be updated if writeQueue is true,
231  // valid bit in LqWriteBundle will be ignored
232  val data_wen_dup = Vec(6, Bool()) // dirty reg dup
233
234
235  def fromLsPipelineBundle(input: LsPipelineBundle, latch: Boolean = false, enable: Bool = true.B) = {
236    if(latch) vaddr := RegEnable(input.vaddr, enable) else vaddr := input.vaddr
237    if(latch) paddr := RegEnable(input.paddr, enable) else paddr := input.paddr
238    if(latch) gpaddr := RegEnable(input.gpaddr, enable) else gpaddr := input.gpaddr
239    if(latch) mask := RegEnable(input.mask, enable) else mask := input.mask
240    if(latch) data := RegEnable(input.data, enable) else data := input.data
241    if(latch) uop := RegEnable(input.uop, enable) else uop := input.uop
242    if(latch) wlineflag := RegEnable(input.wlineflag, enable) else wlineflag := input.wlineflag
243    if(latch) miss := RegEnable(input.miss, enable) else miss := input.miss
244    if(latch) tlbMiss := RegEnable(input.tlbMiss, enable) else tlbMiss := input.tlbMiss
245    if(latch) ptwBack := RegEnable(input.ptwBack, enable) else ptwBack := input.ptwBack
246    if(latch) mmio := RegEnable(input.mmio, enable) else mmio := input.mmio
247    if(latch) atomic := RegEnable(input.atomic, enable) else atomic := input.atomic
248    if(latch) forwardMask := RegEnable(input.forwardMask, enable) else forwardMask := input.forwardMask
249    if(latch) forwardData := RegEnable(input.forwardData, enable) else forwardData := input.forwardData
250    if(latch) isPrefetch := RegEnable(input.isPrefetch, enable) else isPrefetch := input.isPrefetch
251    if(latch) isHWPrefetch := RegEnable(input.isHWPrefetch, enable) else isHWPrefetch := input.isHWPrefetch
252    if(latch) isFrmMisAlignBuf := RegEnable(input.isFrmMisAlignBuf, enable) else isFrmMisAlignBuf := input.isFrmMisAlignBuf
253    if(latch) isFirstIssue := RegEnable(input.isFirstIssue, enable) else isFirstIssue := input.isFirstIssue
254    if(latch) hasROBEntry := RegEnable(input.hasROBEntry, enable) else hasROBEntry := input.hasROBEntry
255    if(latch) isLoadReplay := RegEnable(input.isLoadReplay, enable) else isLoadReplay := input.isLoadReplay
256    if(latch) isFastPath := RegEnable(input.isFastPath, enable) else isFastPath := input.isFastPath
257    if(latch) isFastReplay := RegEnable(input.isFastReplay, enable) else isFastReplay := input.isFastReplay
258    if(latch) mshrid := RegEnable(input.mshrid, enable) else mshrid := input.mshrid
259    if(latch) forward_tlDchannel := RegEnable(input.forward_tlDchannel, enable) else forward_tlDchannel := input.forward_tlDchannel
260    if(latch) replayCarry := RegEnable(input.replayCarry, enable) else replayCarry := input.replayCarry
261    if(latch) dcacheRequireReplay := RegEnable(input.dcacheRequireReplay, enable) else dcacheRequireReplay := input.dcacheRequireReplay
262    if(latch) schedIndex := RegEnable(input.schedIndex, enable) else schedIndex := input.schedIndex
263    if(latch) handledByMSHR := RegEnable(input.handledByMSHR, enable) else handledByMSHR := input.handledByMSHR
264    if(latch) replacementUpdated := RegEnable(input.replacementUpdated, enable) else replacementUpdated := input.replacementUpdated
265    if(latch) missDbUpdated := RegEnable(input.missDbUpdated, enable) else missDbUpdated := input.missDbUpdated
266    if(latch) delayedLoadError := RegEnable(input.delayedLoadError, enable) else delayedLoadError := input.delayedLoadError
267    if(latch) lateKill := RegEnable(input.lateKill, enable) else lateKill := input.lateKill
268    if(latch) feedbacked := RegEnable(input.feedbacked, enable) else feedbacked := input.feedbacked
269    if(latch) isvec               := RegEnable(input.isvec, enable)               else isvec               := input.isvec
270    if(latch) is128bit            := RegEnable(input.is128bit, enable)            else is128bit            := input.is128bit
271    if(latch) vecActive           := RegEnable(input.vecActive, enable)           else vecActive           := input.vecActive
272    if(latch) uop_unit_stride_fof := RegEnable(input.uop_unit_stride_fof, enable) else uop_unit_stride_fof := input.uop_unit_stride_fof
273    if(latch) reg_offset          := RegEnable(input.reg_offset, enable)          else reg_offset          := input.reg_offset
274    if(latch) mbIndex             := RegEnable(input.mbIndex, enable)             else mbIndex             := input.mbIndex
275    if(latch) elemIdxInsideVd     := RegEnable(input.elemIdxInsideVd, enable)     else elemIdxInsideVd     := input.elemIdxInsideVd
276
277    rep_info := DontCare
278    data_wen_dup := DontCare
279  }
280}
281
282class SqWriteBundle(implicit p: Parameters) extends LsPipelineBundle {
283  val need_rep = Bool()
284}
285
286class LoadForwardQueryIO(implicit p: Parameters) extends XSBundle {
287  val vaddr = Output(UInt(VAddrBits.W))
288  val paddr = Output(UInt(PAddrBits.W))
289  val mask = Output(UInt((VLEN/8).W))
290  val uop = Output(new DynInst) // for replay
291  val pc = Output(UInt(VAddrBits.W)) //for debug
292  val valid = Output(Bool())
293
294  val forwardMaskFast = Input(Vec((VLEN/8), Bool())) // resp to load_s1
295  val forwardMask = Input(Vec((VLEN/8), Bool())) // resp to load_s2
296  val forwardData = Input(Vec((VLEN/8), UInt(8.W))) // resp to load_s2
297
298  // val lqIdx = Output(UInt(LoadQueueIdxWidth.W))
299  val sqIdx = Output(new SqPtr)
300
301  // dataInvalid suggests store to load forward found forward should happen,
302  // but data is not available for now. If dataInvalid, load inst should
303  // be replayed from RS. Feedback type should be RSFeedbackType.dataInvalid
304  val dataInvalid = Input(Bool()) // Addr match, but data is not valid for now
305
306  // matchInvalid suggests in store to load forward logic, paddr cam result does
307  // to equal to vaddr cam result. If matchInvalid, a microarchitectural exception
308  // should be raised to flush SQ and committed sbuffer.
309  val matchInvalid = Input(Bool()) // resp to load_s2
310
311  // addrInvalid suggests store to load forward found forward should happen,
312  // but address (SSID) is not available for now. If addrInvalid, load inst should
313  // be replayed from RS. Feedback type should be RSFeedbackType.addrInvalid
314  val addrInvalid = Input(Bool())
315}
316
317// LoadForwardQueryIO used in load pipeline
318//
319// Difference between PipeLoadForwardQueryIO and LoadForwardQueryIO:
320// PipeIO use predecoded sqIdxMask for better forward timing
321class PipeLoadForwardQueryIO(implicit p: Parameters) extends LoadForwardQueryIO {
322  // val sqIdx = Output(new SqPtr) // for debug, should not be used in pipeline for timing reasons
323  // sqIdxMask is calcuated in earlier stage for better timing
324  val sqIdxMask = Output(UInt(StoreQueueSize.W))
325
326  // dataInvalid: addr match, but data is not valid for now
327  val dataInvalidFast = Input(Bool()) // resp to load_s1
328  // val dataInvalid = Input(Bool()) // resp to load_s2
329  val dataInvalidSqIdx = Input(new SqPtr) // resp to load_s2, sqIdx
330  val addrInvalidSqIdx = Input(new SqPtr) // resp to load_s2, sqIdx
331}
332
333// Query load queue for ld-ld violation
334//
335// Req should be send in load_s1
336// Resp will be generated 1 cycle later
337//
338// Note that query req may be !ready, as dcache is releasing a block
339// If it happens, a replay from rs is needed.
340class LoadNukeQueryReq(implicit p: Parameters) extends XSBundle { // provide lqIdx
341  val uop = new DynInst
342  // mask: load's data mask.
343  val mask = UInt((VLEN/8).W)
344
345  // paddr: load's paddr.
346  val paddr      = UInt(PAddrBits.W)
347  // dataInvalid: load data is invalid.
348  val data_valid = Bool()
349}
350
351class LoadNukeQueryResp(implicit p: Parameters) extends XSBundle {
352  // rep_frm_fetch: ld-ld violation check success, replay from fetch.
353  val rep_frm_fetch = Bool()
354}
355
356class LoadNukeQueryIO(implicit p: Parameters) extends XSBundle {
357  val req    = Decoupled(new LoadNukeQueryReq)
358  val resp   = Flipped(Valid(new LoadNukeQueryResp))
359  val revoke = Output(Bool())
360}
361
362class StoreNukeQueryIO(implicit p: Parameters) extends XSBundle {
363  //  robIdx: Requestor's (a store instruction) rob index for match logic.
364  val robIdx = new RobPtr
365
366  //  paddr: requestor's (a store instruction) physical address for match logic.
367  val paddr  = UInt(PAddrBits.W)
368
369  //  mask: requestor's (a store instruction) data width mask for match logic.
370  val mask = UInt((VLEN/8).W)
371
372  // matchLine: if store is vector 128-bits, load unit need to compare 128-bits vaddr.
373  val matchLine = Bool()
374}
375
376class StoreMaBufToSqControlIO(implicit p: Parameters) extends XSBundle {
377  // from storeMisalignBuffer to storeQueue, control it's sbuffer write
378  val control = Output(new XSBundle {
379    // control sq to write-into sb
380    val writeSb = Bool()
381    val wdata = UInt(VLEN.W)
382    val wmask = UInt((VLEN / 8).W)
383    val paddr = UInt(PAddrBits.W)
384    val vaddr = UInt(VAddrBits.W)
385    val last  = Bool()
386    val hasException = Bool()
387    // remove this entry in sq
388    val removeSq = Bool()
389  })
390  // from storeQueue to storeMisalignBuffer, provide detail info of this store
391  val storeInfo = Input(new XSBundle {
392    val data = UInt(VLEN.W)
393    // is the data of the unaligned store ready at sq?
394    val dataReady = Bool()
395    // complete a data transfer from sq to sb
396    val completeSbTrans = Bool()
397  })
398}
399
400// Store byte valid mask write bundle
401//
402// Store byte valid mask write to SQ takes 2 cycles
403class StoreMaskBundle(implicit p: Parameters) extends XSBundle {
404  val sqIdx = new SqPtr
405  val mask = UInt((VLEN/8).W)
406}
407
408class LoadDataFromDcacheBundle(implicit p: Parameters) extends DCacheBundle {
409  // old dcache: optimize data sram read fanout
410  // val bankedDcacheData = Vec(DCacheBanks, UInt(64.W))
411  // val bank_oh = UInt(DCacheBanks.W)
412
413  // new dcache
414  val respDcacheData = UInt(VLEN.W)
415  val forwardMask = Vec(VLEN/8, Bool())
416  val forwardData = Vec(VLEN/8, UInt(8.W))
417  val uop = new DynInst // for data selection, only fwen and fuOpType are used
418  val addrOffset = UInt(4.W) // for data selection
419
420  // forward tilelink D channel
421  val forward_D = Bool()
422  val forwardData_D = Vec(VLEN/8, UInt(8.W))
423
424  // forward mshr data
425  val forward_mshr = Bool()
426  val forwardData_mshr = Vec(VLEN/8, UInt(8.W))
427
428  val forward_result_valid = Bool()
429
430  def dcacheData(): UInt = {
431    // old dcache
432    // val dcache_data = Mux1H(bank_oh, bankedDcacheData)
433    // new dcache
434    val dcache_data = respDcacheData
435    val use_D = forward_D && forward_result_valid
436    val use_mshr = forward_mshr && forward_result_valid
437    Mux(use_D, forwardData_D.asUInt, Mux(use_mshr, forwardData_mshr.asUInt, dcache_data))
438  }
439
440  def mergedData(): UInt = {
441    val rdataVec = VecInit((0 until VLEN / 8).map(j =>
442      Mux(forwardMask(j), forwardData(j), dcacheData()(8*(j+1)-1, 8*j))
443    ))
444    rdataVec.asUInt
445  }
446}
447
448// Load writeback data from load queue (refill)
449class LoadDataFromLQBundle(implicit p: Parameters) extends XSBundle {
450  val lqData = UInt(64.W) // load queue has merged data
451  val uop = new DynInst // for data selection, only fwen and fuOpType are used
452  val addrOffset = UInt(3.W) // for data selection
453
454  def mergedData(): UInt = {
455    lqData
456  }
457}
458
459// Bundle for load / store wait waking up
460class MemWaitUpdateReq(implicit p: Parameters) extends XSBundle {
461  val robIdx = Vec(backendParams.StaExuCnt, ValidIO(new RobPtr))
462  val sqIdx = Vec(backendParams.StdCnt, ValidIO(new SqPtr))
463}
464
465object AddPipelineReg {
466  class PipelineRegModule[T <: Data](gen: T) extends Module {
467    val io = IO(new Bundle() {
468      val in = Flipped(DecoupledIO(gen.cloneType))
469      val out = DecoupledIO(gen.cloneType)
470      val isFlush = Input(Bool())
471    })
472
473    val valid = RegInit(false.B)
474    valid.suggestName("pipeline_reg_valid")
475    when (io.out.fire) { valid := false.B }
476    when (io.in.fire) { valid := true.B }
477    when (io.isFlush) { valid := false.B }
478
479    io.in.ready := !valid || io.out.ready
480    io.out.bits := RegEnable(io.in.bits, io.in.fire)
481    io.out.valid := valid //&& !isFlush
482  }
483
484  def apply[T <: Data]
485  (left: DecoupledIO[T], right: DecoupledIO[T], isFlush: Bool,
486   moduleName: Option[String] = None
487  ): Unit = {
488    val pipelineReg = Module(new PipelineRegModule[T](left.bits.cloneType))
489    if(moduleName.nonEmpty) pipelineReg.suggestName(moduleName.get)
490    pipelineReg.io.in <> left
491    right <> pipelineReg.io.out
492    pipelineReg.io.isFlush := isFlush
493  }
494}