xref: /XiangShan/src/main/scala/xiangshan/backend/rename/Rename.scala (revision d077b11804222346941c6a7dc7188e89b46579a4)
1package xiangshan.backend.rename
2
3import chisel3._
4import chisel3.util._
5import xiangshan._
6import utils.XSInfo
7
8class Rename extends XSModule {
9  val io = IO(new Bundle() {
10    val redirect = Flipped(ValidIO(new Redirect))
11    val roqCommits = Vec(CommitWidth, Flipped(ValidIO(new RoqCommit)))
12    val wbIntResults = Vec(NRWritePorts, Flipped(ValidIO(new ExuOutput)))
13    val wbFpResults = Vec(NRWritePorts, Flipped(ValidIO(new ExuOutput)))
14    val intRfReadAddr = Vec(NRReadPorts, Input(UInt(PhyRegIdxWidth.W)))
15    val fpRfReadAddr = Vec(NRReadPorts, Input(UInt(PhyRegIdxWidth.W)))
16    val intPregRdy = Vec(NRReadPorts, Output(Bool()))
17    val fpPregRdy = Vec(NRReadPorts, Output(Bool()))
18    // from decode buffer
19    val in = Vec(RenameWidth, Flipped(DecoupledIO(new CfCtrl)))
20    // to dispatch1
21    val out = Vec(RenameWidth, DecoupledIO(new MicroOp))
22  })
23
24  def printRenameInfo(in: DecoupledIO[CfCtrl], out: DecoupledIO[MicroOp]) = {
25    XSInfo(
26      in.valid && in.ready,
27      p"pc:${Hexadecimal(in.bits.cf.pc)} in v:${in.valid} in rdy:${in.ready} " +
28        p"lsrc1:${in.bits.ctrl.lsrc1} -> psrc1:${out.bits.psrc1} " +
29        p"lsrc2:${in.bits.ctrl.lsrc2} -> psrc2:${out.bits.psrc2} " +
30        p"lsrc3:${in.bits.ctrl.lsrc3} -> psrc3:${out.bits.psrc3} " +
31        p"ldest:${in.bits.ctrl.ldest} -> pdest:${out.bits.pdest} " +
32        p"old_pdest:${out.bits.old_pdest} " +
33        p"out v:${out.valid} r:${out.ready}\n"
34    )
35  }
36
37  for((x,y) <- io.in.zip(io.out)){
38    printRenameInfo(x, y)
39  }
40
41  val fpFreeList, intFreeList = Module(new FreeList).io
42  val fpRat = Module(new RenameTable(float = true)).io
43  val intRat = Module(new RenameTable(float = false)).io
44  val fpBusyTable, intBusyTable = Module(new BusyTable).io
45
46  fpFreeList.redirect := io.redirect
47  intFreeList.redirect := io.redirect
48
49  val flush = io.redirect.valid && io.redirect.bits.isException
50  fpRat.flush := flush
51  intRat.flush := flush
52  fpBusyTable.flush := flush
53  intBusyTable.flush := flush
54
55  def needDestReg[T <: CfCtrl](fp: Boolean, x: T): Bool = {
56    {if(fp) x.ctrl.fpWen else x.ctrl.rfWen && (x.ctrl.ldest =/= 0.U)}
57  }
58
59  val uops = Wire(Vec(RenameWidth, new MicroOp))
60
61  uops.foreach( uop => {
62//    uop.brMask := DontCare
63//    uop.brTag := DontCare
64    uop.src1State := DontCare
65    uop.src2State := DontCare
66    uop.src3State := DontCare
67    uop.roqIdx := DontCare
68  })
69
70  var lastReady = WireInit(io.out(0).ready)
71  // debug assert
72  val outRdy = Cat(io.out.map(_.ready))
73  assert(outRdy===0.U || outRdy.andR())
74  for(i <- 0 until RenameWidth) {
75    uops(i).cf := io.in(i).bits.cf
76    uops(i).ctrl := io.in(i).bits.ctrl
77    uops(i).brTag := io.in(i).bits.brTag
78
79    val inValid = io.in(i).valid
80
81    // alloc a new phy reg
82    val needFpDest = inValid && needDestReg(fp = true, io.in(i).bits)
83    val needIntDest = inValid && needDestReg(fp = false, io.in(i).bits)
84    fpFreeList.allocReqs(i) := needFpDest && lastReady
85    intFreeList.allocReqs(i) := needIntDest && lastReady
86    val fpCanAlloc = fpFreeList.canAlloc(i)
87    val intCanAlloc = intFreeList.canAlloc(i)
88    val this_can_alloc = Mux(
89      needIntDest,
90      intCanAlloc,
91      Mux(
92        needFpDest,
93        fpCanAlloc,
94        true.B
95      )
96    )
97    io.in(i).ready := lastReady && this_can_alloc
98
99    // do checkpoints when a branch inst come
100    for(fl <- Seq(fpFreeList, intFreeList)){
101      fl.cpReqs(i).valid := inValid
102      fl.cpReqs(i).bits := io.in(i).bits.brTag
103    }
104
105    lastReady = io.in(i).ready
106
107    uops(i).pdest := Mux(needIntDest,
108      intFreeList.pdests(i),
109      Mux(
110        uops(i).ctrl.ldest===0.U && uops(i).ctrl.rfWen,
111        0.U, fpFreeList.pdests(i)
112      )
113    )
114
115    io.out(i).valid := io.in(i).fire()
116    io.out(i).bits := uops(i)
117
118    // write rename table
119    def writeRat(fp: Boolean) = {
120      val rat = if(fp) fpRat else intRat
121      val freeList = if(fp) fpFreeList else intFreeList
122      val busyTable = if(fp) fpBusyTable else intBusyTable
123      // speculative inst write
124      val specWen = freeList.allocReqs(i) && freeList.canAlloc(i)
125      // walk back write
126      val commitDestValid = io.roqCommits(i).valid && needDestReg(fp, io.roqCommits(i).bits.uop)
127      val walkWen = commitDestValid && io.roqCommits(i).bits.isWalk
128
129      rat.specWritePorts(i).wen := specWen || walkWen
130      rat.specWritePorts(i).addr := Mux(specWen, uops(i).ctrl.ldest, io.roqCommits(i).bits.uop.ctrl.ldest)
131      rat.specWritePorts(i).wdata := Mux(specWen, freeList.pdests(i), io.roqCommits(i).bits.uop.old_pdest)
132
133      XSInfo(walkWen,
134        {if(fp) p"fp" else p"int "} + p"walk: pc:${Hexadecimal(io.roqCommits(i).bits.uop.cf.pc)}" +
135          p" ldst:${rat.specWritePorts(i).addr} old_pdest:${rat.specWritePorts(i).wdata}\n"
136      )
137
138      rat.archWritePorts(i).wen := commitDestValid && !io.roqCommits(i).bits.isWalk
139      rat.archWritePorts(i).addr := io.roqCommits(i).bits.uop.ctrl.ldest
140      rat.archWritePorts(i).wdata := io.roqCommits(i).bits.uop.pdest
141
142      XSInfo(rat.archWritePorts(i).wen,
143        {if(fp) p"fp" else p"int "} + p" rat arch: ldest:${rat.archWritePorts(i).addr}" +
144          p" pdest:${rat.archWritePorts(i).wdata}\n"
145      )
146
147      freeList.deallocReqs(i) := rat.archWritePorts(i).wen
148      freeList.deallocPregs(i) := io.roqCommits(i).bits.uop.old_pdest
149
150      // set phy reg status to busy
151      busyTable.allocPregs(i).valid := specWen
152      busyTable.allocPregs(i).bits := freeList.pdests(i)
153    }
154
155    writeRat(fp = false)
156    writeRat(fp = true)
157
158    // read rename table
159    def readRat(lsrcList: List[UInt], ldest: UInt, fp: Boolean) = {
160      val rat = if(fp) fpRat else intRat
161      val srcCnt = lsrcList.size
162      val psrcVec = Wire(Vec(srcCnt, UInt(PhyRegIdxWidth.W)))
163      val old_pdest = Wire(UInt(PhyRegIdxWidth.W))
164      for(k <- 0 until srcCnt+1){
165        val rportIdx = i * (srcCnt+1) + k
166        if(k != srcCnt){
167          rat.readPorts(rportIdx).addr := lsrcList(k)
168          psrcVec(k) := rat.readPorts(rportIdx).rdata
169        } else {
170          rat.readPorts(rportIdx).addr := ldest
171          old_pdest := rat.readPorts(rportIdx).rdata
172        }
173      }
174      (psrcVec, old_pdest)
175    }
176    val lsrcList = List(uops(i).ctrl.lsrc1, uops(i).ctrl.lsrc2, uops(i).ctrl.lsrc3)
177    val ldest = uops(i).ctrl.ldest
178    val (intPhySrcVec, intOldPdest) = readRat(lsrcList.take(2), ldest, fp = false)
179    val (fpPhySrcVec, fpOldPdest) = readRat(lsrcList, ldest, fp = true)
180    uops(i).psrc1 := Mux(uops(i).ctrl.src1Type === SrcType.reg, intPhySrcVec(0), fpPhySrcVec(0))
181    uops(i).psrc2 := Mux(uops(i).ctrl.src2Type === SrcType.reg, intPhySrcVec(1), fpPhySrcVec(1))
182    uops(i).psrc3 := fpPhySrcVec(2)
183    uops(i).old_pdest := Mux(uops(i).ctrl.rfWen, intOldPdest, fpOldPdest)
184  }
185
186
187  def updateBusyTable(fp: Boolean) = {
188    val wbResults = if(fp) io.wbFpResults else io.wbIntResults
189    val busyTable = if(fp) fpBusyTable else intBusyTable
190    for((wb, setPhyRegRdy) <- wbResults.zip(busyTable.wbPregs)){
191      setPhyRegRdy.valid := wb.valid && needDestReg(fp, wb.bits.uop)
192      setPhyRegRdy.bits := wb.bits.uop.pdest
193    }
194  }
195
196  updateBusyTable(false)
197  updateBusyTable(true)
198
199  intBusyTable.rfReadAddr <> io.intRfReadAddr
200  intBusyTable.pregRdy <> io.intPregRdy
201  fpBusyTable.rfReadAddr <> io.fpRfReadAddr
202  fpBusyTable.pregRdy <> io.fpPregRdy
203}
204