xref: /XiangShan/src/main/scala/xiangshan/backend/exu/ExeUnit.scala (revision 81cbff077dfbdc9bccc3bcfb47d9666617c23f0e)
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
31import xiangshan.backend.fu.vector.Bundles.{VType, Vxrm}
32import xiangshan.backend.fu.fpu.Bundles.Frm
33
34class ExeUnitIO(params: ExeUnitParams)(implicit p: Parameters) extends XSBundle {
35  val flush = Flipped(ValidIO(new Redirect()))
36  val in = Flipped(DecoupledIO(new ExuInput(params)))
37  val out = DecoupledIO(new ExuOutput(params))
38  val csrio = OptionWrapper(params.hasCSR, new CSRFileIO)
39  val fenceio = OptionWrapper(params.hasFence, new FenceIO)
40  val frm = OptionWrapper(params.needSrcFrm, Input(Frm()))
41  val vxrm = OptionWrapper(params.needSrcVxrm, Input(Vxrm()))
42  val vtype = OptionWrapper(params.writeVType, new VType)
43}
44
45class ExeUnit(val exuParams: ExeUnitParams)(implicit p: Parameters) extends LazyModule {
46  override def shouldBeInlined: Boolean = false
47
48  lazy val module = new ExeUnitImp(this)(p, exuParams)
49}
50
51class ExeUnitImp(
52  override val wrapper: ExeUnit
53)(implicit
54  p: Parameters, exuParams: ExeUnitParams
55) extends LazyModuleImp(wrapper) with HasXSParameter{
56  private val fuCfgs = exuParams.fuConfigs
57
58  val io = IO(new ExeUnitIO(exuParams))
59
60  val funcUnits = fuCfgs.map(cfg => {
61    assert(cfg.fuGen != null, cfg.name + "Cfg'fuGen is null !!!")
62    val module = cfg.fuGen(p, cfg)
63    module
64  })
65
66  if (EnableClockGate) {
67    fuCfgs.zip(funcUnits).foreach { case (cfg, fu) =>
68      val clk_en = WireInit(false.B)
69      val fuVld_en = WireInit(false.B)
70      val fuVld_en_reg = RegInit(false.B)
71      val uncer_en_reg = RegInit(false.B)
72
73      val lat0 = FuType.isLat0(io.in.bits.fuType)
74      val latN = FuType.isLatN(io.in.bits.fuType)
75      val uncerLat = FuType.isUncerLat(io.in.bits.fuType)
76
77      def lat: Int = cfg.latency.latencyVal.getOrElse(0)
78
79      val fuVldVec = (io.in.valid && latN) +: Seq.fill(lat)(RegInit(false.B))
80      val fuRdyVec = Seq.fill(lat)(Wire(Bool())) :+ io.out.ready
81
82      for (i <- 0 until lat) {
83        fuRdyVec(i) := !fuVldVec(i + 1) || fuRdyVec(i + 1)
84      }
85
86      for (i <- 1 to lat) {
87        when(fuRdyVec(i - 1) && fuVldVec(i - 1)) {
88          fuVldVec(i) := fuVldVec(i - 1)
89        }.elsewhen(fuRdyVec(i)) {
90          fuVldVec(i) := false.B
91        }
92      }
93      fuVld_en := fuVldVec.map(v => v).reduce(_ || _)
94      fuVld_en_reg := fuVld_en
95
96      when(uncerLat && io.in.fire) {
97        uncer_en_reg := true.B
98      }.elsewhen(uncerLat && io.out.fire) {
99        uncer_en_reg := false.B
100      }
101
102      when(lat0 && io.in.fire) {
103        clk_en := true.B
104      }.elsewhen(latN && fuVld_en || fuVld_en_reg) {
105        clk_en := true.B
106      }.elsewhen(uncerLat && io.in.fire || uncer_en_reg) {
107        clk_en := true.B
108      }
109
110      if (cfg.ckAlwaysEn) {
111        clk_en := true.B
112      }
113
114      val clk_gate = Module(new ClockGate)
115      clk_gate.io.TE := false.B
116      clk_gate.io.E := clk_en
117      clk_gate.io.CK := clock
118      fu.clock := clk_gate.io.Q
119      XSPerfAccumulate(s"clock_gate_en_${fu.cfg.name}", clk_en)
120    }
121  }
122
123  val busy = RegInit(false.B)
124  if (exuParams.latencyCertain){
125    busy := false.B
126  }
127  else {
128    val robIdx = RegEnable(io.in.bits.robIdx, io.in.fire)
129    when(io.in.fire && io.in.bits.robIdx.needFlush(io.flush)) {
130      busy := false.B
131    }.elsewhen(busy && robIdx.needFlush(io.flush)) {
132      busy := false.B
133    }.elsewhen(io.out.fire) {
134      busy := false.B
135    }.elsewhen(io.in.fire) {
136      busy := true.B
137    }
138  }
139
140  exuParams.wbPortConfigs.map{
141    x => x match {
142      case IntWB(port, priority) => assert(priority >= 0 && priority <= 2,
143        s"${exuParams.name}: WbPort must priority=0 or priority=1")
144      case VfWB (port, priority) => assert(priority >= 0 && priority <= 2,
145        s"${exuParams.name}: WbPort must priority=0 or priority=1")
146      case _ =>
147    }
148  }
149  val intWbPort = exuParams.getIntWBPort
150  if (intWbPort.isDefined){
151    val sameIntPortExuParam = backendParams.allExuParams.filter(_.getIntWBPort.isDefined)
152      .filter(_.getIntWBPort.get.port == intWbPort.get.port)
153    val samePortOneCertainOneUncertain = sameIntPortExuParam.map(_.latencyCertain).contains(true) && sameIntPortExuParam.map(_.latencyCertain).contains(false)
154    if (samePortOneCertainOneUncertain) sameIntPortExuParam.map(samePort =>
155      samePort.wbPortConfigs.map(
156        x => x match {
157          case IntWB(port, priority) => {
158            if (!samePort.latencyCertain) assert(priority == sameIntPortExuParam.size - 1,
159              s"${samePort.name}: IntWbPort $port must latencyCertain priority=0 or latencyUnCertain priority=max(${sameIntPortExuParam.size - 1})")
160            // Certain latency can be handled by WbBusyTable, so there is no need to limit the exu's WB priority
161          }
162          case _ =>
163        }
164      )
165    )
166  }
167  val vfWbPort = exuParams.getVfWBPort
168  if (vfWbPort.isDefined) {
169    val sameVfPortExuParam = backendParams.allExuParams.filter(_.getVfWBPort.isDefined)
170      .filter(_.getVfWBPort.get.port == vfWbPort.get.port)
171    val samePortOneCertainOneUncertain = sameVfPortExuParam.map(_.latencyCertain).contains(true) && sameVfPortExuParam.map(_.latencyCertain).contains(false)
172    if (samePortOneCertainOneUncertain)  sameVfPortExuParam.map(samePort =>
173      samePort.wbPortConfigs.map(
174        x => x match {
175          case VfWB(port, priority) => {
176            if (!samePort.latencyCertain) assert(priority == sameVfPortExuParam.size - 1,
177              s"${samePort.name}: VfWbPort $port must latencyCertain priority=0 or latencyUnCertain priority=max(${sameVfPortExuParam.size - 1})")
178            // Certain latency can be handled by WbBusyTable, so there is no need to limit the exu's WB priority
179          }
180          case _ =>
181        }
182      )
183    )
184  }
185  if(backendParams.debugEn) {
186    dontTouch(io.out.ready)
187  }
188  // rob flush --> funcUnits
189  funcUnits.zipWithIndex.foreach { case (fu, i) =>
190    fu.io.flush <> io.flush
191  }
192
193  def acceptCond(input: ExuInput): Seq[Bool] = {
194    input.params.fuConfigs.map(_.fuSel(input))
195  }
196
197  val in1ToN = Module(new Dispatcher(new ExuInput(exuParams), funcUnits.length, acceptCond))
198
199  // ExeUnit.in <---> Dispatcher.in
200  in1ToN.io.in.valid := io.in.valid && !busy
201  in1ToN.io.in.bits := io.in.bits
202  io.in.ready := !busy && in1ToN.io.in.ready
203
204  // Dispatcher.out <---> FunctionUnits
205  in1ToN.io.out.zip(funcUnits.map(_.io.in)).foreach {
206    case (source: DecoupledIO[ExuInput], sink: DecoupledIO[FuncUnitInput]) =>
207      sink.valid := source.valid
208      source.ready := sink.ready
209
210      sink.bits.data.src.zip(source.bits.src).foreach { case(fuSrc, exuSrc) => fuSrc := exuSrc }
211      sink.bits.data.pc          .foreach(x => x := source.bits.pc.get)
212      sink.bits.data.imm         := source.bits.imm
213      sink.bits.ctrl.fuOpType    := source.bits.fuOpType
214      sink.bits.ctrl.robIdx      := source.bits.robIdx
215      sink.bits.ctrl.pdest       := source.bits.pdest
216      sink.bits.ctrl.rfWen       .foreach(x => x := source.bits.rfWen.get)
217      sink.bits.ctrl.fpWen       .foreach(x => x := source.bits.fpWen.get)
218      sink.bits.ctrl.vecWen      .foreach(x => x := source.bits.vecWen.get)
219      sink.bits.ctrl.flushPipe   .foreach(x => x := source.bits.flushPipe.get)
220      sink.bits.ctrl.preDecode   .foreach(x => x := source.bits.preDecode.get)
221      sink.bits.ctrl.ftqIdx      .foreach(x => x := source.bits.ftqIdx.get)
222      sink.bits.ctrl.ftqOffset   .foreach(x => x := source.bits.ftqOffset.get)
223      sink.bits.ctrl.predictInfo .foreach(x => x := source.bits.predictInfo.get)
224      sink.bits.ctrl.fpu         .foreach(x => x := source.bits.fpu.get)
225      sink.bits.ctrl.vpu         .foreach(x => x := source.bits.vpu.get)
226      sink.bits.perfDebugInfo    := source.bits.perfDebugInfo
227  }
228
229  private val fuOutValidOH = funcUnits.map(_.io.out.valid)
230  XSError(PopCount(fuOutValidOH) > 1.U, p"fuOutValidOH ${Binary(VecInit(fuOutValidOH).asUInt)} should be one-hot)\n")
231  private val fuOutBitsVec = funcUnits.map(_.io.out.bits)
232  private val fuRedirectVec: Seq[Option[ValidIO[Redirect]]] = funcUnits.map(_.io.out.bits.res.redirect)
233
234  // Assume that one fu can only write int or fp or vec,
235  // otherwise, wenVec should be assigned to wen in fu.
236  private val fuIntWenVec = funcUnits.map(x => x.cfg.needIntWen.B && x.io.out.bits.ctrl.rfWen.getOrElse(false.B))
237  private val fuFpWenVec  = funcUnits.map(x => x.cfg.needFpWen.B  && x.io.out.bits.ctrl.fpWen.getOrElse(false.B))
238  private val fuVecWenVec = funcUnits.map(x => x.cfg.needVecWen.B && x.io.out.bits.ctrl.vecWen.getOrElse(false.B))
239  // FunctionUnits <---> ExeUnit.out
240  io.out.valid := Cat(fuOutValidOH).orR
241  funcUnits.foreach(fu => fu.io.out.ready := io.out.ready)
242
243  // select one fu's result
244  io.out.bits.data := Mux1H(fuOutValidOH, fuOutBitsVec.map(_.res.data))
245  io.out.bits.robIdx := Mux1H(fuOutValidOH, fuOutBitsVec.map(_.ctrl.robIdx))
246  io.out.bits.pdest := Mux1H(fuOutValidOH, fuOutBitsVec.map(_.ctrl.pdest))
247  io.out.bits.intWen.foreach(x => x := Mux1H(fuOutValidOH, fuIntWenVec))
248  io.out.bits.fpWen.foreach(x => x := Mux1H(fuOutValidOH, fuFpWenVec))
249  io.out.bits.vecWen.foreach(x => x := Mux1H(fuOutValidOH, fuVecWenVec))
250  io.out.bits.redirect.foreach(x => x := Mux1H((fuOutValidOH zip fuRedirectVec).filter(_._2.isDefined).map(x => (x._1, x._2.get))))
251  io.out.bits.fflags.foreach(x => x := Mux1H(fuOutValidOH, fuOutBitsVec.map(_.res.fflags.getOrElse(0.U.asTypeOf(io.out.bits.fflags.get)))))
252  io.out.bits.wflags.foreach(x => x := Mux1H(fuOutValidOH, fuOutBitsVec.map(_.ctrl.fpu.getOrElse(0.U.asTypeOf(new FPUCtrlSignals)).wflags)))
253  io.out.bits.vxsat.foreach(x => x := Mux1H(fuOutValidOH, fuOutBitsVec.map(_.res.vxsat.getOrElse(0.U.asTypeOf(io.out.bits.vxsat.get)))))
254  io.out.bits.exceptionVec.foreach(x => x := Mux1H(fuOutValidOH, fuOutBitsVec.map(_.ctrl.exceptionVec.getOrElse(0.U.asTypeOf(io.out.bits.exceptionVec.get)))))
255  io.out.bits.flushPipe.foreach(x => x := Mux1H(fuOutValidOH, fuOutBitsVec.map(_.ctrl.flushPipe.getOrElse(0.U.asTypeOf(io.out.bits.flushPipe.get)))))
256  io.out.bits.replay.foreach(x => x := Mux1H(fuOutValidOH, fuOutBitsVec.map(_.ctrl.replay.getOrElse(0.U.asTypeOf(io.out.bits.replay.get)))))
257  io.out.bits.predecodeInfo.foreach(x => x := Mux1H(fuOutValidOH, fuOutBitsVec.map(_.ctrl.preDecode.getOrElse(0.U.asTypeOf(io.out.bits.predecodeInfo.get)))))
258
259  io.csrio.foreach(exuio => funcUnits.foreach(fu => fu.io.csrio.foreach{
260    fuio =>
261      exuio <> fuio
262      fuio.exception := DelayN(exuio.exception, 2)
263  }))
264
265  io.vtype.foreach(exuio => funcUnits.foreach(fu => fu.io.vtype.foreach(fuio => exuio := fuio)))
266  io.fenceio.foreach(exuio => funcUnits.foreach(fu => fu.io.fenceio.foreach(fuio => fuio <> exuio)))
267  io.frm.foreach(exuio => funcUnits.foreach(fu => fu.io.frm.foreach(fuio => fuio <> exuio)))
268  io.vxrm.foreach(exuio => funcUnits.foreach(fu => fu.io.vxrm.foreach(fuio => fuio <> exuio)))
269
270  // debug info
271  io.out.bits.debug     := 0.U.asTypeOf(io.out.bits.debug)
272  io.out.bits.debug.isPerfCnt := funcUnits.map(_.io.csrio.map(_.isPerfCnt)).map(_.getOrElse(false.B)).reduce(_ || _)
273  io.out.bits.debugInfo := Mux1H(fuOutValidOH, fuOutBitsVec.map(_.perfDebugInfo))
274}
275
276class DispatcherIO[T <: Data](private val gen: T, n: Int) extends Bundle {
277  val in = Flipped(DecoupledIO(gen))
278
279  val out = Vec(n, DecoupledIO(gen))
280}
281
282class Dispatcher[T <: Data](private val gen: T, n: Int, acceptCond: T => Seq[Bool])
283  (implicit p: Parameters)
284  extends Module {
285
286  val io = IO(new DispatcherIO(gen, n))
287
288  private val acceptVec: Vec[Bool] = VecInit(acceptCond(io.in.bits))
289
290  XSError(io.in.valid && PopCount(acceptVec) > 1.U, s"s[ExeUnit] accept vec should no more than 1, ${Binary(acceptVec.asUInt)} ")
291  XSError(io.in.valid && PopCount(acceptVec) === 0.U, "[ExeUnit] there is a inst not dispatched to any fu")
292
293  io.out.zipWithIndex.foreach { case (out, i) =>
294    out.valid := acceptVec(i) && io.in.valid
295    out.bits := io.in.bits
296  }
297
298  io.in.ready := Mux1H(acceptVec,io.out.map(_.ready))
299}
300
301class MemExeUnitIO (implicit p: Parameters) extends XSBundle {
302  val flush = Flipped(ValidIO(new Redirect()))
303  val in = Flipped(DecoupledIO(new MemExuInput()))
304  val out = DecoupledIO(new MemExuOutput())
305}
306
307class MemExeUnit(exuParams: ExeUnitParams)(implicit p: Parameters) extends XSModule {
308  val io = IO(new MemExeUnitIO)
309  val fu = exuParams.fuConfigs.head.fuGen(p, exuParams.fuConfigs.head)
310  fu.io.flush             := io.flush
311  fu.io.in.valid          := io.in.valid
312  io.in.ready             := fu.io.in.ready
313
314  fu.io.in.bits.ctrl.robIdx    := io.in.bits.uop.robIdx
315  fu.io.in.bits.ctrl.pdest     := io.in.bits.uop.pdest
316  fu.io.in.bits.ctrl.fuOpType  := io.in.bits.uop.fuOpType
317  fu.io.in.bits.data.imm       := io.in.bits.uop.imm
318  fu.io.in.bits.data.src.zip(io.in.bits.src).foreach(x => x._1 := x._2)
319  fu.io.in.bits.perfDebugInfo := io.in.bits.uop.debugInfo
320
321  io.out.valid            := fu.io.out.valid
322  fu.io.out.ready         := io.out.ready
323
324  io.out.bits             := 0.U.asTypeOf(io.out.bits) // dontCare other fields
325  io.out.bits.data        := fu.io.out.bits.res.data
326  io.out.bits.uop.robIdx  := fu.io.out.bits.ctrl.robIdx
327  io.out.bits.uop.pdest   := fu.io.out.bits.ctrl.pdest
328  io.out.bits.uop.fuType  := io.in.bits.uop.fuType
329  io.out.bits.uop.fuOpType:= io.in.bits.uop.fuOpType
330  io.out.bits.uop.sqIdx   := io.in.bits.uop.sqIdx
331  io.out.bits.uop.debugInfo := fu.io.out.bits.perfDebugInfo
332
333  io.out.bits.debug       := 0.U.asTypeOf(io.out.bits.debug)
334}
335