xref: /XiangShan/src/main/scala/xiangshan/backend/fu/Jump.scala (revision 3fce4f48e1f4c43253ff1758dbd05b8b71627990) 
1package xiangshan.backend.fu
2
3import chisel3._
4import chisel3.util._
5import xiangshan._
6import utils._
7import xiangshan.backend._
8import xiangshan.backend.fu.FunctionUnit._
9import xiangshan.backend.decode.isa._
10
11trait HasRedirectOut { this: RawModule =>
12  val redirectOutValid = IO(Output(Bool()))
13  val redirectOut = IO(Output(new Redirect))
14  val brUpdate = IO(Output(new BranchUpdateInfo))
15}
16
17class Jump extends FunctionUnit(
18  FuConfig(FuType.jmp, 1, 0, writeIntRf = true, writeFpRf = false, hasRedirect = true)
19) with HasRedirectOut {
20
21  val (src1, offset, func, pc, uop) = (
22    io.in.bits.src(0),
23    io.in.bits.uop.ctrl.imm,
24    io.in.bits.uop.ctrl.fuOpType,
25    SignExt(io.in.bits.uop.cf.pc, AddrBits),
26    io.in.bits.uop
27  )
28
29  val redirectHit = uop.roqIdx.needFlush(io.redirectIn)
30  val valid = io.in.valid && !redirectHit
31
32  val isRVC = uop.cf.brUpdate.pd.isRVC
33  val snpc = Mux(isRVC, pc + 2.U, pc + 4.U)
34  val target = src1 + offset // NOTE: src1 is (pc/rf(rs1)), src2 is (offset)
35
36  redirectOutValid := valid
37  redirectOut.pc := uop.cf.pc
38  redirectOut.target := target
39  redirectOut.brTag := uop.brTag
40  redirectOut.isException := false.B
41  redirectOut.isFlushPipe := false.B
42  redirectOut.isMisPred := DontCare // check this in brq
43  redirectOut.isReplay := false.B
44  redirectOut.roqIdx := uop.roqIdx
45
46  brUpdate := uop.cf.brUpdate
47  brUpdate.pc := uop.cf.pc
48  brUpdate.target := target
49  brUpdate.brTarget := target // DontCare
50  brUpdate.taken := true.B
51
52  // Output
53  val res = snpc
54
55  io.in.ready := io.out.ready
56  io.out.valid := valid
57  io.out.bits.uop <> io.in.bits.uop
58  io.out.bits.data := res
59
60  // NOTE: the debug info is for one-cycle exec, if FMV needs multi-cycle, may needs change it
61  XSDebug(io.in.valid, "In(%d %d) Out(%d %d) Redirect:(%d %d %d %d) brTag:%x\n",
62    io.in.valid,
63    io.in.ready,
64    io.out.valid,
65    io.out.ready,
66    io.redirectIn.valid,
67    io.redirectIn.bits.isException,
68    io.redirectIn.bits.isFlushPipe,
69    redirectHit,
70    io.redirectIn.bits.brTag.value
71  )
72  XSDebug(io.in.valid, "src1:%x offset:%x func:%b type:JUMP pc:%x res:%x\n", src1, offset, func, pc, res)
73}
74