xref: /XiangShan/src/main/scala/xiangshan/backend/issue/IssueQueue.scala (revision 9f93c361863a6261d0f1bb9502242fef769aae4b)
1package xiangshan.backend.issue
2
3import chisel3._
4import chisel3.util._
5import xiangshan._
6
7trait IQConst{
8  val iqSize = 8
9  val iqIdxWidth = log2Up(iqSize)
10  val layer1Size = iqSize
11  val layer2Size = iqSize/2
12  val layer3Size = iqSize/4
13}
14
15sealed abstract class IQBundle extends XSBundle with IQConst
16sealed abstract class IQModule extends XSModule with IQConst with NeedImpl
17
18sealed class CmpInputBundle extends IQBundle{
19  val instRdy = Input(Bool())
20  val roqIdx  = Input(UInt(RoqIdxWidth.W))
21  val iqIdx   = Input(UInt(iqIdxWidth.W))
22}
23
24
25sealed class CompareCircuitUnit(layer: Int = 0, id: Int = 0) extends IQModule {
26  val io = IO(new Bundle(){
27    val in1 = new CmpInputBundle
28    val in2 = new CmpInputBundle
29    val out = Flipped(new CmpInputBundle)
30  })
31
32  val roqIdx1 = io.in1.roqIdx
33  val roqIdx2 = io.in2.roqIdx
34  val iqIdx1  = io.in1.iqIdx
35  val iqIdx2  = io.in2.iqIdx
36
37  val inst1Rdy = io.in1.instRdy
38  val inst2Rdy = io.in2.instRdy
39
40  val readySignal = Cat(inst1Rdy,inst2Rdy)
41
42  switch (readySignal) {
43    is ("b00".U) {
44      io.out.instRdy := false.B
45      io.out.roqIdx := DontCare
46      io.out.iqIdx := DontCare
47    }
48    is ("b01".U) {
49      io.out.instRdy := inst2Rdy
50      io.out.roqIdx := roqIdx2
51      io.out.iqIdx := iqIdx2
52     }
53    is ("b10".U) {
54      io.out.instRdy := inst1Rdy
55      io.out.roqIdx := roqIdx1
56      io.out.iqIdx := iqIdx1
57    }
58    is ("b11".U) {
59      when(roqIdx1 < roqIdx2) {
60        io.out.instRdy := inst1Rdy
61        io.out.roqIdx := roqIdx1
62        io.out.iqIdx := iqIdx1
63      } .otherwise {
64        io.out.instRdy := inst2Rdy
65        io.out.roqIdx := roqIdx2
66        io.out.iqIdx := iqIdx2
67      }
68    }
69  }
70
71}
72
73class IssueQueue(val fuTypeInt: BigInt, wakeupCnt: Int, val bypassCnt: Int) extends IQModule {
74
75  val useBypass = bypassCnt > 0
76
77  val io = IO(new Bundle() {
78    // flush Issue Queue
79    val redirect = Flipped(ValidIO(new Redirect))
80
81    // enq Ctrl sigs at dispatch-2
82    val enqCtrl = Flipped(DecoupledIO(new MicroOp))
83    // enq Data at next cycle (regfile has 1 cycle latency)
84    val enqData = Flipped(ValidIO(new ExuInput))
85
86    //  broadcast selected uop to other issue queues which has bypasses
87    val selectedUop = if(useBypass) DecoupledIO(new MicroOp) else null
88
89    // send to exu
90    val deq = DecoupledIO(new ExuInput)
91
92    // listen to write back bus
93    val wakeUpPorts = Vec(wakeupCnt, Flipped(DecoupledIO(new ExuOutput)))
94
95    // use bypass uops to speculative wake-up
96    val bypassUops = if(useBypass) Vec(bypassCnt, Flipped(DecoupledIO(new MicroOp))) else null
97    val bypassData = if(useBypass) Vec(bypassCnt, Flipped(DecoupledIO(new ExuOutput))) else null
98  })
99  //---------------------------------------------------------
100  // Issue Queue
101  //---------------------------------------------------------
102
103  //Tag Queue
104  val ctrlFlow = Mem(iqSize,new CtrlFlow)
105  val ctrlSig = Mem(iqSize,new CtrlSignals)
106  val brMask  = RegInit(VecInit(Seq.fill(iqSize)(0.U(BrqSize.W))))
107  val valid   = RegInit(VecInit(Seq.fill(iqSize)(false.B)))
108  val src1Rdy = RegInit(VecInit(Seq.fill(iqSize)(false.B)))
109  val src2Rdy = RegInit(VecInit(Seq.fill(iqSize)(false.B)))
110  //val src3Rdy = RegInit(VecInit(Seq.fill(iqSize)(false.B)))
111  val prfSrc1 = Reg(Vec(iqSize, UInt(PhyRegIdxWidth.W)))
112  val prfSrc2 = Reg(Vec(iqSize, UInt(PhyRegIdxWidth.W)))
113  //val prfSrc3 = Reg(Vec(iqSize, UInt(PhyRegIdxWidth.W)))
114  val prfDest = Reg(Vec(iqSize, UInt(PhyRegIdxWidth.W)))
115  val oldPDest = Reg(Vec(iqSize, UInt(PhyRegIdxWidth.W)))
116  val freelistAllocPrt = Reg(Vec(iqSize, UInt(PhyRegIdxWidth.W)))
117  val roqIdx  = Reg(Vec(iqSize, UInt(RoqIdxWidth.W)))
118
119  val instRdy = WireInit(VecInit(List.tabulate(iqSize)(i => src1Rdy(i) && src2Rdy(i) && valid(i))))
120
121
122  //tag enqueue
123  val iqEmty = !valid.asUInt.orR
124  val iqFull =  valid.asUInt.andR
125  val iqAllowIn = !iqFull
126  io.enqCtrl.ready := iqAllowIn
127
128  //enqueue pointer
129  val emptySlot = ~valid.asUInt
130  val enqueueSelect = PriorityEncoder(emptySlot)
131
132  when(io.enqCtrl.fire()){
133    ctrlFlow(enqueueSelect) := io.enqCtrl.bits.cf
134    ctrlSig(enqueueSelect) := io.enqCtrl.bits.ctrl
135    brMask(enqueueSelect) := io.enqCtrl.bits.brMask
136    valid(enqueueSelect) := true.B
137    src1Rdy(enqueueSelect) := io.enqCtrl.bits.src1State === SrcState.rdy
138    src2Rdy(enqueueSelect) := io.enqCtrl.bits.src2State === SrcState.rdy
139    // src3Rdy(enqueueSelect) := io.enqCtrl.bits.src3State === SrcState.rdy
140    prfSrc1(enqueueSelect) := io.enqCtrl.bits.psrc1
141    prfSrc2(enqueueSelect) := io.enqCtrl.bits.psrc2
142    //prfSrc3(enqueueSelect) := io.enqCtrl.bits.psrc3
143    prfDest(enqueueSelect) := io.enqCtrl.bits.pdest
144    oldPDest(enqueueSelect) := io.enqCtrl.bits.old_pdest
145    freelistAllocPrt(enqueueSelect) := io.enqCtrl.bits.freelistAllocPtr
146    roqIdx(enqueueSelect) := io.enqCtrl.bits.roqIdx
147
148  }
149
150  //Data Queue
151  val src1Data    = Reg(Vec(iqSize, UInt(XLEN.W)))
152  val src2Data    = Reg(Vec(iqSize, UInt(XLEN.W)))
153
154
155  //---------------------------------------------------------
156  // Select Circuit
157  //---------------------------------------------------------
158  //layer 1
159  val layer1CCUs = (0 until layer1Size by 2) map { i =>
160    val CCU_1 = Module(new CompareCircuitUnit(layer = 1, id = i/2))
161    CCU_1.io.in1.instRdy := instRdy(i)
162    CCU_1.io.in1.roqIdx  := roqIdx(i)
163    CCU_1.io.in1.iqIdx   := i.U
164
165    CCU_1.io.in2.instRdy := instRdy(i+1)
166    CCU_1.io.in2.roqIdx  := roqIdx(i+1)
167    CCU_1.io.in2.iqIdx   := (i+1).U
168
169    CCU_1
170  }
171
172  //layer 2
173  val layer2CCUs = (0 until layer2Size by 2) map { i =>
174    val CCU_2 = Module(new CompareCircuitUnit(layer = 2, id = i/2))
175    CCU_2.io.in1.instRdy := layer1CCUs(i).io.out.instRdy
176    CCU_2.io.in1.roqIdx  := layer1CCUs(i).io.out.roqIdx
177    CCU_2.io.in1.iqIdx   := layer1CCUs(i).io.out.iqIdx
178
179    CCU_2.io.in2.instRdy := layer1CCUs(i+1).io.out.instRdy
180    CCU_2.io.in2.roqIdx  := layer1CCUs(i+1).io.out.roqIdx
181    CCU_2.io.in2.iqIdx   := layer1CCUs(i+1).io.out.iqIdx
182
183    CCU_2
184  }
185
186  //layer 3
187  val CCU_3 = Module(new CompareCircuitUnit(layer = 3, id = 0))
188  CCU_3.io.in1.instRdy := layer2CCUs(0).io.out.instRdy
189  CCU_3.io.in1.roqIdx  := layer2CCUs(0).io.out.roqIdx
190  CCU_3.io.in1.iqIdx   := layer2CCUs(0).io.out.iqIdx
191
192  CCU_3.io.in2.instRdy := layer2CCUs(1).io.out.instRdy
193  CCU_3.io.in2.roqIdx  := layer2CCUs(1).io.out.roqIdx
194  CCU_3.io.in2.iqIdx   := layer2CCUs(1).io.out.iqIdx
195
196
197
198
199
200
201}
202