xref: /XiangShan/src/main/scala/xiangshan/backend/fu/Jump.scala (revision 9ca85825513f5faea1a8a8e28263b701e88816a4)
1package xiangshan.backend.fu
2
3import chisel3._
4import chisel3.util._
5import xiangshan._
6import utils._
7import xiangshan.backend._
8import xiangshan.backend.decode.ImmUnion
9import xiangshan.backend.fu.FunctionUnit._
10import xiangshan.backend.decode.isa._
11
12trait HasRedirectOut { this: RawModule =>
13  val redirectOutValid = IO(Output(Bool()))
14  val redirectOut = IO(Output(new Redirect))
15}
16
17class JumpDataModule extends XSModule {
18  val io = IO(new Bundle() {
19    val src1 = Input(UInt(XLEN.W))
20    val pc = Input(UInt(XLEN.W)) // sign-ext to XLEN
21    val immMin = Input(UInt(ImmUnion.maxLen.W))
22    val func = Input(FuOpType())
23    val isRVC = Input(Bool())
24    val result, target = Output(UInt(XLEN.W))
25    val isAuipc = Output(Bool())
26  })
27  val (src1, pc, immMin, func, isRVC) = (io.src1, io.pc, io.immMin, io.func, io.isRVC)
28
29  val isJalr = JumpOpType.jumpOpisJalr(func)
30  val isAuipc = JumpOpType.jumpOpisAuipc(func)
31  val offset = SignExt(ParallelMux(Seq(
32    isJalr -> ImmUnion.I.toImm32(immMin),
33    isAuipc -> ImmUnion.U.toImm32(immMin),
34    !(isJalr || isAuipc) -> ImmUnion.J.toImm32(immMin)
35  )), XLEN)
36
37  val snpc = Mux(isRVC, pc + 2.U, pc + 4.U)
38  val target = src1 + offset // NOTE: src1 is (pc/rf(rs1)), src2 is (offset)
39
40  io.target := target
41  io.result := Mux(JumpOpType.jumpOpisAuipc(func), target, snpc)
42  io.isAuipc := isAuipc
43}
44
45class Jump extends FunctionUnit with HasRedirectOut {
46
47  val (src1, jalr_target, pc, immMin, func, uop) = (
48    io.in.bits.src(0),
49    io.in.bits.src(1)(VAddrBits - 1, 0),
50    SignExt(io.in.bits.uop.cf.pc, XLEN),
51    io.in.bits.uop.ctrl.imm,
52    io.in.bits.uop.ctrl.fuOpType,
53    io.in.bits.uop
54  )
55
56  val redirectHit = uop.roqIdx.needFlush(io.redirectIn, io.flushIn)
57  val valid = io.in.valid
58  val isRVC = uop.cf.pd.isRVC
59
60  val jumpDataModule = Module(new JumpDataModule)
61  jumpDataModule.io.src1 := src1
62  jumpDataModule.io.pc := pc
63  jumpDataModule.io.immMin := immMin
64  jumpDataModule.io.func := func
65  jumpDataModule.io.isRVC := isRVC
66
67  redirectOutValid := valid && !jumpDataModule.io.isAuipc
68  redirectOut := DontCare
69  redirectOut.cfiUpdate.target := jumpDataModule.io.target
70  redirectOut.level := RedirectLevel.flushAfter
71  redirectOut.roqIdx := uop.roqIdx
72  redirectOut.ftqIdx := uop.cf.ftqPtr
73  redirectOut.ftqOffset := uop.cf.ftqOffset
74  redirectOut.cfiUpdate.predTaken := true.B
75  redirectOut.cfiUpdate.taken := true.B
76  redirectOut.cfiUpdate.target := jumpDataModule.io.target
77  redirectOut.cfiUpdate.isMisPred := jumpDataModule.io.target =/= jalr_target || !uop.cf.pred_taken
78
79  io.in.ready := io.out.ready
80  io.out.valid := valid
81  io.out.bits.uop <> io.in.bits.uop
82  io.out.bits.data := jumpDataModule.io.result
83
84  // NOTE: the debug info is for one-cycle exec, if FMV needs multi-cycle, may needs change it
85  XSDebug(io.in.valid, "In(%d %d) Out(%d %d) Redirect:(%d %d %d)\n",
86    io.in.valid,
87    io.in.ready,
88    io.out.valid,
89    io.out.ready,
90    io.redirectIn.valid,
91    io.redirectIn.bits.level,
92    redirectHit
93  )
94}
95