xref: /XiangShan/src/main/scala/xiangshan/backend/exu/ExeUnit.scala (revision ac4d321d18df4775b9ddda83e77cf526a0b1ca67)
1/***************************************************************************************
2* Copyright (c) 2020-2021 Institute of Computing Technology, Chinese Academy of Sciences
3* Copyright (c) 2020-2021 Peng Cheng Laboratory
4*
5* XiangShan is licensed under Mulan PSL v2.
6* You can use this software according to the terms and conditions of the Mulan PSL v2.
7* You may obtain a copy of Mulan PSL v2 at:
8*          http://license.coscl.org.cn/MulanPSL2
9*
10* THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
11* EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
12* MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
13*
14* See the Mulan PSL v2 for more details.
15***************************************************************************************/
16
17package xiangshan.backend.exu
18
19import org.chipsalliance.cde.config.Parameters
20import chisel3._
21import chisel3.experimental.hierarchy.{Definition, instantiable}
22import chisel3.util._
23import freechips.rocketchip.diplomacy.{LazyModule, LazyModuleImp}
24import utility.DelayN
25import utils._
26import xiangshan.backend.fu.{CSRFileIO, FenceIO, FuncUnitInput}
27import xiangshan.backend.Bundles.{ExuInput, ExuOutput, MemExuInput, MemExuOutput}
28import xiangshan.{FPUCtrlSignals, HasXSParameter, Redirect, XSBundle, XSModule}
29import xiangshan.backend.datapath.WbConfig.{PregWB, _}
30import xiangshan.backend.fu.FuType
31
32class ExeUnitIO(params: ExeUnitParams)(implicit p: Parameters) extends XSBundle {
33  val flush = Flipped(ValidIO(new Redirect()))
34  val in = Flipped(DecoupledIO(new ExuInput(params)))
35  val out = DecoupledIO(new ExuOutput(params))
36  val csrio = if (params.hasCSR) Some(new CSRFileIO) else None
37  val fenceio = if (params.hasFence) Some(new FenceIO) else None
38  val frm = if (params.needSrcFrm) Some(Input(UInt(3.W))) else None
39  val vxrm = if (params.needSrcVxrm) Some(Input(UInt(2.W))) else None
40}
41
42class ExeUnit(val exuParams: ExeUnitParams)(implicit p: Parameters) extends LazyModule {
43  override def shouldBeInlined: Boolean = false
44
45  lazy val module = new ExeUnitImp(this)(p, exuParams)
46}
47
48class ExeUnitImp(
49  override val wrapper: ExeUnit
50)(implicit
51  p: Parameters, exuParams: ExeUnitParams
52) extends LazyModuleImp(wrapper) with HasXSParameter{
53  private val fuCfgs = exuParams.fuConfigs
54
55  val io = IO(new ExeUnitIO(exuParams))
56
57  val funcUnits = fuCfgs.map(cfg => {
58    assert(cfg.fuGen != null, cfg.name + "Cfg'fuGen is null !!!")
59    val module = cfg.fuGen(p, cfg)
60    module
61  })
62
63  if (EnableClockGate) {
64    fuCfgs.zip(funcUnits).foreach { case (cfg, fu) =>
65      val clk_en = WireInit(false.B)
66      val fuVld_en = WireInit(false.B)
67      val fuVld_en_reg = RegInit(false.B)
68      val uncer_en_reg = RegInit(false.B)
69
70      val lat0 = FuType.isLat0(io.in.bits.fuType)
71      val latN = FuType.isLatN(io.in.bits.fuType)
72      val uncerLat = FuType.isUncerLat(io.in.bits.fuType)
73
74      def lat: Int = cfg.latency.latencyVal.getOrElse(0)
75
76      val fuVldVec = (io.in.valid && latN) +: Seq.fill(lat)(RegInit(false.B))
77      val fuRdyVec = Seq.fill(lat)(Wire(Bool())) :+ io.out.ready
78
79      for (i <- 0 until lat) {
80        fuRdyVec(i) := !fuVldVec(i + 1) || fuRdyVec(i + 1)
81      }
82
83      for (i <- 1 to lat) {
84        when(fuRdyVec(i - 1) && fuVldVec(i - 1)) {
85          fuVldVec(i) := fuVldVec(i - 1)
86        }.elsewhen(fuRdyVec(i)) {
87          fuVldVec(i) := false.B
88        }
89      }
90      fuVld_en := fuVldVec.map(v => v).reduce(_ || _)
91      fuVld_en_reg := fuVld_en
92
93      when(uncerLat && io.in.fire) {
94        uncer_en_reg := true.B
95      }.elsewhen(uncerLat && io.out.fire) {
96        uncer_en_reg := false.B
97      }
98
99      when(lat0 && io.in.fire) {
100        clk_en := true.B
101      }.elsewhen(latN && fuVld_en || fuVld_en_reg) {
102        clk_en := true.B
103      }.elsewhen(uncerLat && io.in.fire || uncer_en_reg) {
104        clk_en := true.B
105      }
106
107      if (cfg.ckAlwaysEn) {
108        clk_en := true.B
109      }
110
111      val clk_gate = Module(new ClockGate)
112      clk_gate.io.TE := false.B
113      clk_gate.io.E := clk_en
114      clk_gate.io.CK := clock
115      fu.clock := clk_gate.io.Q
116      XSPerfAccumulate(s"clock_gate_en_${fu.cfg.name}", clk_en)
117    }
118  }
119
120  val busy = RegInit(false.B)
121  if (exuParams.latencyCertain){
122    busy := false.B
123  }
124  else {
125    val robIdx = RegEnable(io.in.bits.robIdx, io.in.fire)
126    when(io.in.fire && io.in.bits.robIdx.needFlush(io.flush)) {
127      busy := false.B
128    }.elsewhen(busy && robIdx.needFlush(io.flush)) {
129      busy := false.B
130    }.elsewhen(io.out.fire) {
131      busy := false.B
132    }.elsewhen(io.in.fire) {
133      busy := true.B
134    }
135  }
136
137  exuParams.wbPortConfigs.map{
138    x => x match {
139      case IntWB(port, priority) => assert(priority >= 0 && priority <= 2,
140        s"${exuParams.name}: WbPort must priority=0 or priority=1")
141      case VfWB (port, priority) => assert(priority >= 0 && priority <= 2,
142        s"${exuParams.name}: WbPort must priority=0 or priority=1")
143      case _ =>
144    }
145  }
146  val intWbPort = exuParams.getIntWBPort
147  if (intWbPort.isDefined){
148    val sameIntPortExuParam = backendParams.allExuParams.filter(_.getIntWBPort.isDefined)
149      .filter(_.getIntWBPort.get.port == intWbPort.get.port)
150    val samePortOneCertainOneUncertain = sameIntPortExuParam.map(_.latencyCertain).contains(true) && sameIntPortExuParam.map(_.latencyCertain).contains(false)
151    if (samePortOneCertainOneUncertain) sameIntPortExuParam.map(samePort =>
152      samePort.wbPortConfigs.map(
153        x => x match {
154          case IntWB(port, priority) => {
155            if (!samePort.latencyCertain) assert(priority == sameIntPortExuParam.size - 1,
156              s"${samePort.name}: IntWbPort $port must latencyCertain priority=0 or latencyUnCertain priority=max(${sameIntPortExuParam.size - 1})")
157            // Certain latency can be handled by WbBusyTable, so there is no need to limit the exu's WB priority
158          }
159          case _ =>
160        }
161      )
162    )
163  }
164  val vfWbPort = exuParams.getVfWBPort
165  if (vfWbPort.isDefined) {
166    val sameVfPortExuParam = backendParams.allExuParams.filter(_.getVfWBPort.isDefined)
167      .filter(_.getVfWBPort.get.port == vfWbPort.get.port)
168    val samePortOneCertainOneUncertain = sameVfPortExuParam.map(_.latencyCertain).contains(true) && sameVfPortExuParam.map(_.latencyCertain).contains(false)
169    if (samePortOneCertainOneUncertain)  sameVfPortExuParam.map(samePort =>
170      samePort.wbPortConfigs.map(
171        x => x match {
172          case VfWB(port, priority) => {
173            if (!samePort.latencyCertain) assert(priority == sameVfPortExuParam.size - 1,
174              s"${samePort.name}: VfWbPort $port must latencyCertain priority=0 or latencyUnCertain priority=max(${sameVfPortExuParam.size - 1})")
175            // Certain latency can be handled by WbBusyTable, so there is no need to limit the exu's WB priority
176          }
177          case _ =>
178        }
179      )
180    )
181  }
182  if(backendParams.debugEn) {
183    dontTouch(io.out.ready)
184  }
185  // rob flush --> funcUnits
186  funcUnits.zipWithIndex.foreach { case (fu, i) =>
187    fu.io.flush <> io.flush
188  }
189
190  def acceptCond(input: ExuInput): Seq[Bool] = {
191    input.params.fuConfigs.map(_.fuSel(input))
192  }
193
194  val in1ToN = Module(new Dispatcher(new ExuInput(exuParams), funcUnits.length, acceptCond))
195
196  // ExeUnit.in <---> Dispatcher.in
197  in1ToN.io.in.valid := io.in.valid && !busy
198  in1ToN.io.in.bits := io.in.bits
199  io.in.ready := !busy && in1ToN.io.in.ready
200
201  // Dispatcher.out <---> FunctionUnits
202  in1ToN.io.out.zip(funcUnits.map(_.io.in)).foreach {
203    case (source: DecoupledIO[ExuInput], sink: DecoupledIO[FuncUnitInput]) =>
204      sink.valid := source.valid
205      source.ready := sink.ready
206
207      sink.bits.data.src.zip(source.bits.src).foreach { case(fuSrc, exuSrc) => fuSrc := exuSrc }
208      sink.bits.data.pc          .foreach(x => x := source.bits.pc.get)
209      sink.bits.data.imm         := source.bits.imm
210      sink.bits.ctrl.fuOpType    := source.bits.fuOpType
211      sink.bits.ctrl.robIdx      := source.bits.robIdx
212      sink.bits.ctrl.pdest       := source.bits.pdest
213      sink.bits.ctrl.rfWen       .foreach(x => x := source.bits.rfWen.get)
214      sink.bits.ctrl.fpWen       .foreach(x => x := source.bits.fpWen.get)
215      sink.bits.ctrl.vecWen      .foreach(x => x := source.bits.vecWen.get)
216      sink.bits.ctrl.flushPipe   .foreach(x => x := source.bits.flushPipe.get)
217      sink.bits.ctrl.preDecode   .foreach(x => x := source.bits.preDecode.get)
218      sink.bits.ctrl.ftqIdx      .foreach(x => x := source.bits.ftqIdx.get)
219      sink.bits.ctrl.ftqOffset   .foreach(x => x := source.bits.ftqOffset.get)
220      sink.bits.ctrl.predictInfo .foreach(x => x := source.bits.predictInfo.get)
221      sink.bits.ctrl.fpu         .foreach(x => x := source.bits.fpu.get)
222      sink.bits.ctrl.vpu         .foreach(x => x := source.bits.vpu.get)
223      sink.bits.perfDebugInfo    := source.bits.perfDebugInfo
224  }
225
226  private val fuOutValidOH = funcUnits.map(_.io.out.valid)
227  XSError(PopCount(fuOutValidOH) > 1.U, p"fuOutValidOH ${Binary(VecInit(fuOutValidOH).asUInt)} should be one-hot)\n")
228  private val fuOutBitsVec = funcUnits.map(_.io.out.bits)
229  private val fuRedirectVec: Seq[Option[ValidIO[Redirect]]] = funcUnits.map(_.io.out.bits.res.redirect)
230
231  // Assume that one fu can only write int or fp or vec,
232  // otherwise, wenVec should be assigned to wen in fu.
233  private val fuIntWenVec = funcUnits.map(x => x.cfg.needIntWen.B && x.io.out.bits.ctrl.rfWen.getOrElse(false.B))
234  private val fuFpWenVec  = funcUnits.map(x => x.cfg.needFpWen.B  && x.io.out.bits.ctrl.fpWen.getOrElse(false.B))
235  private val fuVecWenVec = funcUnits.map(x => x.cfg.needVecWen.B && x.io.out.bits.ctrl.vecWen.getOrElse(false.B))
236  // FunctionUnits <---> ExeUnit.out
237  io.out.valid := Cat(fuOutValidOH).orR
238  funcUnits.foreach(fu => fu.io.out.ready := io.out.ready)
239
240  // select one fu's result
241  io.out.bits.data := Mux1H(fuOutValidOH, fuOutBitsVec.map(_.res.data))
242  io.out.bits.robIdx := Mux1H(fuOutValidOH, fuOutBitsVec.map(_.ctrl.robIdx))
243  io.out.bits.pdest := Mux1H(fuOutValidOH, fuOutBitsVec.map(_.ctrl.pdest))
244  io.out.bits.intWen.foreach(x => x := Mux1H(fuOutValidOH, fuIntWenVec))
245  io.out.bits.fpWen.foreach(x => x := Mux1H(fuOutValidOH, fuFpWenVec))
246  io.out.bits.vecWen.foreach(x => x := Mux1H(fuOutValidOH, fuVecWenVec))
247  io.out.bits.redirect.foreach(x => x := Mux1H((fuOutValidOH zip fuRedirectVec).filter(_._2.isDefined).map(x => (x._1, x._2.get))))
248  io.out.bits.fflags.foreach(x => x := Mux1H(fuOutValidOH, fuOutBitsVec.map(_.res.fflags.getOrElse(0.U.asTypeOf(io.out.bits.fflags.get)))))
249  io.out.bits.wflags.foreach(x => x := Mux1H(fuOutValidOH, fuOutBitsVec.map(_.ctrl.fpu.getOrElse(0.U.asTypeOf(new FPUCtrlSignals)).wflags)))
250  io.out.bits.vxsat.foreach(x => x := Mux1H(fuOutValidOH, fuOutBitsVec.map(_.res.vxsat.getOrElse(0.U.asTypeOf(io.out.bits.vxsat.get)))))
251  io.out.bits.exceptionVec.foreach(x => x := Mux1H(fuOutValidOH, fuOutBitsVec.map(_.ctrl.exceptionVec.getOrElse(0.U.asTypeOf(io.out.bits.exceptionVec.get)))))
252  io.out.bits.flushPipe.foreach(x => x := Mux1H(fuOutValidOH, fuOutBitsVec.map(_.ctrl.flushPipe.getOrElse(0.U.asTypeOf(io.out.bits.flushPipe.get)))))
253  io.out.bits.replay.foreach(x => x := Mux1H(fuOutValidOH, fuOutBitsVec.map(_.ctrl.replay.getOrElse(0.U.asTypeOf(io.out.bits.replay.get)))))
254  io.out.bits.predecodeInfo.foreach(x => x := Mux1H(fuOutValidOH, fuOutBitsVec.map(_.ctrl.preDecode.getOrElse(0.U.asTypeOf(io.out.bits.predecodeInfo.get)))))
255
256  io.csrio.foreach(exuio => funcUnits.foreach(fu => fu.io.csrio.foreach{
257    fuio =>
258      exuio <> fuio
259      fuio.exception := DelayN(exuio.exception, 2)
260  }))
261  io.fenceio.foreach(exuio => funcUnits.foreach(fu => fu.io.fenceio.foreach(fuio => fuio <> exuio)))
262  io.frm.foreach(exuio => funcUnits.foreach(fu => fu.io.frm.foreach(fuio => fuio <> exuio)))
263  io.vxrm.foreach(exuio => funcUnits.foreach(fu => fu.io.vxrm.foreach(fuio => fuio <> exuio)))
264
265  // debug info
266  io.out.bits.debug     := 0.U.asTypeOf(io.out.bits.debug)
267  io.out.bits.debug.isPerfCnt := funcUnits.map(_.io.csrio.map(_.isPerfCnt)).map(_.getOrElse(false.B)).reduce(_ || _)
268  io.out.bits.debugInfo := Mux1H(fuOutValidOH, fuOutBitsVec.map(_.perfDebugInfo))
269}
270
271class DispatcherIO[T <: Data](private val gen: T, n: Int) extends Bundle {
272  val in = Flipped(DecoupledIO(gen))
273
274  val out = Vec(n, DecoupledIO(gen))
275}
276
277class Dispatcher[T <: Data](private val gen: T, n: Int, acceptCond: T => Seq[Bool])
278  (implicit p: Parameters)
279  extends Module {
280
281  val io = IO(new DispatcherIO(gen, n))
282
283  private val acceptVec: Vec[Bool] = VecInit(acceptCond(io.in.bits))
284
285  XSError(io.in.valid && PopCount(acceptVec) > 1.U, s"s[ExeUnit] accept vec should no more than 1, ${Binary(acceptVec.asUInt)} ")
286  XSError(io.in.valid && PopCount(acceptVec) === 0.U, "[ExeUnit] there is a inst not dispatched to any fu")
287
288  io.out.zipWithIndex.foreach { case (out, i) =>
289    out.valid := acceptVec(i) && io.in.valid
290    out.bits := io.in.bits
291  }
292
293  io.in.ready := Mux1H(acceptVec,io.out.map(_.ready))
294}
295
296class MemExeUnitIO (implicit p: Parameters) extends XSBundle {
297  val flush = Flipped(ValidIO(new Redirect()))
298  val in = Flipped(DecoupledIO(new MemExuInput()))
299  val out = DecoupledIO(new MemExuOutput())
300}
301
302class MemExeUnit(exuParams: ExeUnitParams)(implicit p: Parameters) extends XSModule {
303  val io = IO(new MemExeUnitIO)
304  val fu = exuParams.fuConfigs.head.fuGen(p, exuParams.fuConfigs.head)
305  fu.io.flush             := io.flush
306  fu.io.in.valid          := io.in.valid
307  io.in.ready             := fu.io.in.ready
308
309  fu.io.in.bits.ctrl.robIdx    := io.in.bits.uop.robIdx
310  fu.io.in.bits.ctrl.pdest     := io.in.bits.uop.pdest
311  fu.io.in.bits.ctrl.fuOpType  := io.in.bits.uop.fuOpType
312  fu.io.in.bits.data.imm       := io.in.bits.uop.imm
313  fu.io.in.bits.data.src.zip(io.in.bits.src).foreach(x => x._1 := x._2)
314  fu.io.in.bits.perfDebugInfo := io.in.bits.uop.debugInfo
315
316  io.out.valid            := fu.io.out.valid
317  fu.io.out.ready         := io.out.ready
318
319  io.out.bits             := 0.U.asTypeOf(io.out.bits) // dontCare other fields
320  io.out.bits.data        := fu.io.out.bits.res.data
321  io.out.bits.uop.robIdx  := fu.io.out.bits.ctrl.robIdx
322  io.out.bits.uop.pdest   := fu.io.out.bits.ctrl.pdest
323  io.out.bits.uop.fuType  := io.in.bits.uop.fuType
324  io.out.bits.uop.fuOpType:= io.in.bits.uop.fuOpType
325  io.out.bits.uop.sqIdx   := io.in.bits.uop.sqIdx
326  io.out.bits.uop.debugInfo := fu.io.out.bits.perfDebugInfo
327
328  io.out.bits.debug       := 0.U.asTypeOf(io.out.bits.debug)
329}
330