xref: /XiangShan/src/main/scala/xiangshan/backend/rename/Rename.scala (revision 4b3d9f67355a9945cd5eca46929b89c130c43c26)
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    // from decode buffer
13    val in = Vec(RenameWidth, Flipped(DecoupledIO(new CfCtrl)))
14    // to dispatch1
15    val out = Vec(RenameWidth, DecoupledIO(new MicroOp))
16  })
17
18  def printRenameInfo(in: DecoupledIO[CfCtrl], out: DecoupledIO[MicroOp]) = {
19    XSInfo(
20      in.valid && in.ready,
21      p"pc:${Hexadecimal(in.bits.cf.pc)} in v:${in.valid} in rdy:${in.ready} " +
22        p"lsrc1:${in.bits.ctrl.lsrc1} -> psrc1:${out.bits.psrc1} " +
23        p"lsrc2:${in.bits.ctrl.lsrc2} -> psrc2:${out.bits.psrc2} " +
24        p"lsrc3:${in.bits.ctrl.lsrc3} -> psrc3:${out.bits.psrc3} " +
25        p"ldest:${in.bits.ctrl.ldest} -> pdest:${out.bits.pdest} " +
26        p"old_pdest:${out.bits.old_pdest} " +
27        p"out v:${out.valid} r:${out.ready}\n"
28    )
29  }
30
31  for((x,y) <- io.in.zip(io.out)){
32    printRenameInfo(x, y)
33  }
34
35  val fpFreeList, intFreeList = Module(new FreeList).io
36  val fpRat = Module(new RenameTable(float = true)).io
37  val intRat = Module(new RenameTable(float = false)).io
38
39  fpFreeList.redirect := io.redirect
40  intFreeList.redirect := io.redirect
41
42  val flush = io.redirect.valid && (io.redirect.bits.isException || io.redirect.bits.isFlushPipe) // TODO: need check by JiaWei
43  fpRat.flush := flush
44  intRat.flush := flush
45
46  def needDestReg[T <: CfCtrl](fp: Boolean, x: T): Bool = {
47    {if(fp) x.ctrl.fpWen else x.ctrl.rfWen && (x.ctrl.ldest =/= 0.U)}
48  }
49
50  val uops = Wire(Vec(RenameWidth, new MicroOp))
51
52  uops.foreach( uop => {
53//    uop.brMask := DontCare
54//    uop.brTag := DontCare
55    uop.src1State := DontCare
56    uop.src2State := DontCare
57    uop.src3State := DontCare
58    uop.roqIdx := DontCare
59    uop.diffTestDebugLrScValid := DontCare
60    uop.lqIdx := DontCare
61    uop.sqIdx := DontCare
62  })
63
64  var lastReady = WireInit(io.out(0).ready)
65  // debug assert
66  val outRdy = Cat(io.out.map(_.ready))
67  assert(outRdy===0.U || outRdy.andR())
68  for(i <- 0 until RenameWidth) {
69    uops(i).cf := io.in(i).bits.cf
70    uops(i).ctrl := io.in(i).bits.ctrl
71    uops(i).brTag := io.in(i).bits.brTag
72
73    val inValid = io.in(i).valid
74
75    // alloc a new phy reg
76    val needFpDest = inValid && needDestReg(fp = true, io.in(i).bits)
77    val needIntDest = inValid && needDestReg(fp = false, io.in(i).bits)
78    fpFreeList.allocReqs(i) := needFpDest && lastReady
79    intFreeList.allocReqs(i) := needIntDest && lastReady
80    val fpCanAlloc = fpFreeList.canAlloc(i)
81    val intCanAlloc = intFreeList.canAlloc(i)
82    val this_can_alloc = Mux(
83      needIntDest,
84      intCanAlloc,
85      Mux(
86        needFpDest,
87        fpCanAlloc,
88        true.B
89      )
90    )
91    io.in(i).ready := lastReady && this_can_alloc
92
93    // do checkpoints when a branch inst come
94    for(fl <- Seq(fpFreeList, intFreeList)){
95      fl.cpReqs(i).valid := inValid
96      fl.cpReqs(i).bits := io.in(i).bits.brTag
97    }
98
99    lastReady = io.in(i).ready
100
101    uops(i).pdest := Mux(needIntDest,
102      intFreeList.pdests(i),
103      Mux(
104        uops(i).ctrl.ldest===0.U && uops(i).ctrl.rfWen,
105        0.U, fpFreeList.pdests(i)
106      )
107    )
108
109    io.out(i).valid := io.in(i).fire()
110    io.out(i).bits := uops(i)
111
112    // write rename table
113    def writeRat(fp: Boolean) = {
114      val rat = if(fp) fpRat else intRat
115      val freeList = if(fp) fpFreeList else intFreeList
116      // speculative inst write
117      val specWen = freeList.allocReqs(i) && freeList.canAlloc(i)
118      // walk back write
119      val commitDestValid = io.roqCommits(i).valid && needDestReg(fp, io.roqCommits(i).bits.uop)
120      val walkWen = commitDestValid && io.roqCommits(i).bits.isWalk
121
122      rat.specWritePorts(i).wen := specWen || walkWen
123      rat.specWritePorts(i).addr := Mux(specWen, uops(i).ctrl.ldest, io.roqCommits(i).bits.uop.ctrl.ldest)
124      rat.specWritePorts(i).wdata := Mux(specWen, freeList.pdests(i), io.roqCommits(i).bits.uop.old_pdest)
125
126      XSInfo(walkWen,
127        {if(fp) p"fp" else p"int "} + p"walk: pc:${Hexadecimal(io.roqCommits(i).bits.uop.cf.pc)}" +
128          p" ldest:${rat.specWritePorts(i).addr} old_pdest:${rat.specWritePorts(i).wdata}\n"
129      )
130
131      rat.archWritePorts(i).wen := commitDestValid && !io.roqCommits(i).bits.isWalk
132      rat.archWritePorts(i).addr := io.roqCommits(i).bits.uop.ctrl.ldest
133      rat.archWritePorts(i).wdata := io.roqCommits(i).bits.uop.pdest
134
135      XSInfo(rat.archWritePorts(i).wen,
136        {if(fp) p"fp" else p"int "} + p" rat arch: ldest:${rat.archWritePorts(i).addr}" +
137          p" pdest:${rat.archWritePorts(i).wdata}\n"
138      )
139
140      freeList.deallocReqs(i) := rat.archWritePorts(i).wen
141      freeList.deallocPregs(i) := io.roqCommits(i).bits.uop.old_pdest
142
143    }
144
145    writeRat(fp = false)
146    writeRat(fp = true)
147
148    // read rename table
149    def readRat(lsrcList: List[UInt], ldest: UInt, fp: Boolean) = {
150      val rat = if(fp) fpRat else intRat
151      val srcCnt = lsrcList.size
152      val psrcVec = Wire(Vec(srcCnt, UInt(PhyRegIdxWidth.W)))
153      val old_pdest = Wire(UInt(PhyRegIdxWidth.W))
154      for(k <- 0 until srcCnt+1){
155        val rportIdx = i * (srcCnt+1) + k
156        if(k != srcCnt){
157          rat.readPorts(rportIdx).addr := lsrcList(k)
158          psrcVec(k) := rat.readPorts(rportIdx).rdata
159        } else {
160          rat.readPorts(rportIdx).addr := ldest
161          old_pdest := rat.readPorts(rportIdx).rdata
162        }
163      }
164      (psrcVec, old_pdest)
165    }
166    val lsrcList = List(uops(i).ctrl.lsrc1, uops(i).ctrl.lsrc2, uops(i).ctrl.lsrc3)
167    val ldest = uops(i).ctrl.ldest
168    val (intPhySrcVec, intOldPdest) = readRat(lsrcList.take(2), ldest, fp = false)
169    val (fpPhySrcVec, fpOldPdest) = readRat(lsrcList, ldest, fp = true)
170    uops(i).psrc1 := Mux(uops(i).ctrl.src1Type === SrcType.reg, intPhySrcVec(0), fpPhySrcVec(0))
171    uops(i).psrc2 := Mux(uops(i).ctrl.src2Type === SrcType.reg, intPhySrcVec(1), fpPhySrcVec(1))
172    uops(i).psrc3 := fpPhySrcVec(2)
173    uops(i).old_pdest := Mux(uops(i).ctrl.rfWen, intOldPdest, fpOldPdest)
174  }
175
176
177
178}
179