xref: /XiangShan/src/main/scala/xiangshan/backend/Backend.scala (revision f4553cb70de7e51d79e327d4cf932cc1fabac2a2)
1package xiangshan.backend
2
3import bus.simplebus.SimpleBusUC
4import chisel3._
5import chisel3.util._
6import chisel3.util.experimental.BoringUtils
7import noop.MemMMUIO
8import xiangshan._
9import xiangshan.backend.decode.{DecodeBuffer, DecodeStage}
10import xiangshan.backend.rename.Rename
11import xiangshan.backend.brq.Brq
12import xiangshan.backend.dispatch.Dispatch
13import xiangshan.backend.exu._
14import xiangshan.backend.issue.IssueQueue
15import xiangshan.backend.regfile.{Regfile, RfWritePort}
16import xiangshan.backend.roq.Roq
17
18
19/** Backend Pipeline:
20  * Decode -> Rename -> Dispatch-1 -> Dispatch-2 -> Issue -> Exe
21  */
22class Backend(implicit val p: XSConfig) extends XSModule
23  with HasExeUnits
24  with NeedImpl
25{
26  val io = IO(new Bundle {
27    val dmem = new SimpleBusUC(addrBits = VAddrBits)
28    val memMMU = Flipped(new MemMMUIO)
29    val frontend = Flipped(new FrontendToBackendIO)
30  })
31
32
33  val decode = Module(new DecodeStage)
34  val brq = Module(new Brq)
35  val decBuf = Module(new DecodeBuffer)
36  val rename = Module(new Rename)
37  val dispatch = Module(new Dispatch)
38  val roq = Module(new Roq)
39  val intRf = Module(new Regfile(
40    numReadPorts = NRReadPorts,
41    numWirtePorts = NRWritePorts,
42    hasZero = true
43  ))
44  val fpRf = Module(new Regfile(
45    numReadPorts = NRReadPorts,
46    numWirtePorts = NRWritePorts,
47    hasZero = false
48  ))
49  val redirect = Mux(roq.io.redirect.valid, roq.io.redirect, brq.io.redirect)
50  val issueQueues = exeUnits.zipWithIndex.map({ case(eu, i) =>
51    def needBypass(x: Exu): Boolean = eu.enableBypass
52    val bypassCnt = exeUnits.count(needBypass)//if(eu.fuTypeInt == FuType.alu.litValue()) exuConfig.AluCnt else 0
53    def needWakeup(x: Exu): Boolean = (eu.readIntRf && x.writeIntRf) || (eu.readFpRf && x.writeFpRf)
54    val wakeupCnt = exeUnits.count(needWakeup)
55    assert(!(needBypass(eu) && !needWakeup(eu))) // needBypass but dont needWakeup is not allowed
56    val iq = Module(new IssueQueue(eu.fuTypeInt, wakeupCnt, bypassCnt, eu.fixedDelay, fifo = eu.fuTypeInt == FuType.ldu.litValue()))
57    iq.io.redirect <> redirect
58    iq.io.enqCtrl <> dispatch.io.enqIQCtrl(i)
59    iq.io.enqData <> dispatch.io.enqIQData(i)
60    val wuUnitsOut = exeUnits.filter(e => needWakeup(e)).map(_.io.out)
61    for(i <- iq.io.wakeUpPorts.indices) {
62      iq.io.wakeUpPorts(i).bits <> wuUnitsOut(i).bits
63      iq.io.wakeUpPorts(i).valid := wuUnitsOut(i).valid
64    }
65    println(s"[$i] $eu Queue wakeupCnt:$wakeupCnt bypassCnt:$bypassCnt")
66    eu.io.in <> iq.io.deq
67    eu.io.redirect <> redirect
68    iq
69  })
70
71  val bypassQueues = issueQueues.filter(_.bypassCnt > 0)
72  val bypassUnits = exeUnits.filter(_.enableBypass)
73  bypassQueues.foreach(iq => {
74    for(i <- iq.io.bypassUops.indices) {
75      iq.io.bypassData(i).bits := bypassUnits(i).io.out.bits
76      iq.io.bypassData(i).valid := bypassUnits(i).io.out.valid
77    }
78    iq.io.bypassUops <> bypassQueues.map(_.io.selectedUop)
79  })
80  // val aluQueues = issueQueues.filter(_.fuTypeInt == FuType.alu.litValue())
81  // aluQueues.foreach(aluQ => {
82  //   aluQ.io.bypassUops <> aluQueues.map(_.io.selectedUop)
83  //   aluQ.io.bypassData <> aluExeUnits.map(_.io.out)
84  // })
85
86  lsuExeUnits.foreach(_.io.dmem <> io.dmem)
87  lsuExeUnits.foreach(_.io.scommit <> roq.io.scommit)
88
89  io.frontend.redirect <> redirect
90  io.frontend.commits <> roq.io.commits
91
92  decode.io.in <> io.frontend.cfVec
93  brq.io.roqRedirect <> roq.io.redirect
94  brq.io.enqReqs <> decode.io.toBrq
95  for((x, y) <- brq.io.exuRedirect.zip(exeUnits.filter(_.hasRedirect))){
96    x.bits := y.io.out.bits
97    x.valid := y.io.out.fire() && y.io.out.bits.redirectValid
98  }
99  decode.io.brMasks <> brq.io.brMasks
100  decode.io.brTags <> brq.io.brTags
101  decBuf.io.redirect <> redirect
102  decBuf.io.in <> decode.io.out
103
104  rename.io.redirect <> redirect
105  rename.io.roqCommits <> roq.io.commits
106  rename.io.in <> decBuf.io.out
107  rename.io.intRfReadAddr <> dispatch.io.readIntRf.map(_.addr)
108  rename.io.fpRfReadAddr <> dispatch.io.readFpRf.map(_.addr)
109  rename.io.intPregRdy <> dispatch.io.intPregRdy
110  rename.io.fpPregRdy <> dispatch.io.fpPregRdy
111
112  dispatch.io.redirect <> redirect
113  dispatch.io.fromRename <> rename.io.out
114
115  roq.io.brqRedirect <> brq.io.redirect
116  roq.io.dp1Req <> dispatch.io.toRoq
117  dispatch.io.roqIdxs <> roq.io.roqIdxs
118
119  intRf.io.readPorts <> dispatch.io.readIntRf
120  fpRf.io.readPorts <> dispatch.io.readFpRf
121
122  val exeWbReqs = exeUnits.map(_.io.out)
123
124  val wbIntIdx = exeUnits.zipWithIndex.filter(_._1.writeIntRf).map(_._2)
125  val wbFpIdx = exeUnits.zipWithIndex.filter(_._1.writeFpRf).map(_._2)
126
127  val wbu = Module(new Wbu(wbIntIdx, wbFpIdx))
128  wbu.io.in <> exeWbReqs
129
130  val wbIntResults = wbu.io.toIntRf
131  val wbFpResults = wbu.io.toFpRf
132
133  def exuOutToRfWrite(x: Valid[ExuOutput]): RfWritePort = {
134    val rfWrite = Wire(new RfWritePort)
135    rfWrite.wen := x.valid
136    rfWrite.addr := x.bits.uop.pdest
137    rfWrite.data := x.bits.data
138    rfWrite
139  }
140
141  intRf.io.writePorts <> wbIntResults.map(exuOutToRfWrite)
142  fpRf.io.writePorts <> wbFpResults.map(exuOutToRfWrite)
143
144  rename.io.wbIntResults <> wbIntResults
145  rename.io.wbFpResults <> wbFpResults
146
147  roq.io.exeWbResults.take(exeWbReqs.length).zip(wbu.io.toRoq).foreach(x => x._1 := x._2)
148  roq.io.exeWbResults.last := brq.io.out
149
150
151  // TODO: Remove sink and source
152  val tmp = WireInit(0.U)
153  val sinks = Array[String](
154    "DTLBFINISH",
155    "DTLBPF",
156    "DTLBENABLE",
157    "perfCntCondMdcacheLoss",
158    "perfCntCondMl2cacheLoss",
159    "perfCntCondMdcacheHit",
160    "lsuMMIO",
161    "perfCntCondMl2cacheHit",
162    "perfCntCondMl2cacheReq",
163    "mtip",
164    "perfCntCondMdcacheReq",
165    "meip"
166  )
167  for (s <- sinks){ BoringUtils.addSink(tmp, s) }
168
169}
170