xref: /XiangShan/src/main/scala/xiangshan/backend/fu/Jump.scala (revision d077b11804222346941c6a7dc7188e89b46579a4)
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
11class Jump extends FunctionUnit(jmpCfg){
12  val io = IO(new ExuIO)
13
14  val (iovalid, src1, offset, func, pc, uop) = (io.in.valid, io.in.bits.src1, io.in.bits.uop.ctrl.imm, io.in.bits.uop.ctrl.fuOpType, SignExt(io.in.bits.uop.cf.pc, AddrBits), io.in.bits.uop)
15
16  val redirectHit = uop.needFlush(io.redirect)
17  val valid = iovalid && !redirectHit
18
19  val isRVC = uop.cf.brUpdate.pd.isRVC
20  val pcDelaySlot = Mux(isRVC, pc + 2.U, pc + 4.U)
21  val target = src1 + offset // NOTE: src1 is (pc/rf(rs1)), src2 is (offset)
22
23  io.out.bits.redirectValid := valid
24  io.out.bits.redirect.pc := uop.cf.pc
25  io.out.bits.redirect.target := target
26  io.out.bits.redirect.brTag := uop.brTag
27  io.out.bits.redirect.isException := false.B
28  io.out.bits.redirect.isMisPred := DontCare // check this in brq
29  io.out.bits.redirect.isReplay := false.B
30  io.out.bits.redirect.roqIdx := uop.roqIdx
31
32  io.out.bits.brUpdate := uop.cf.brUpdate
33  io.out.bits.brUpdate.pc := uop.cf.pc
34  io.out.bits.brUpdate.target := target
35  io.out.bits.brUpdate.brTarget := target // DontCare
36  // io.out.bits.brUpdate.btbType := LookupTree(func, RV32I_BRUInstr.bruFuncTobtbTypeTable)
37  io.out.bits.brUpdate.taken := true.B
38  // io.out.bits.brUpdate.fetchIdx := uop.cf.brUpdate.fetchOffset >> 1.U  //TODO: consider RVC
39
40  // Output
41  val res = pcDelaySlot
42
43  io.in.ready := io.out.ready
44  io.out.valid := valid // TODO: CSR/MOU/FMV may need change it
45  io.out.bits.uop <> io.in.bits.uop
46  io.out.bits.data := res
47
48  io.dmem <> DontCare
49  io.out.bits.debug <> DontCare
50
51  // NOTE: the debug info is for one-cycle exec, if FMV needs multi-cycle, may needs change it
52  XSDebug(io.in.valid, "In(%d %d) Out(%d %d) Redirect:(%d %d %d) brTag:%x\n",
53    io.in.valid,
54    io.in.ready,
55    io.out.valid,
56    io.out.ready,
57    io.redirect.valid,
58    io.redirect.bits.isException,
59    redirectHit,
60    io.redirect.bits.brTag.value
61  )
62  XSDebug(io.in.valid, "src1:%x offset:%x func:%b type:JUMP pc:%x res:%x\n", src1, offset, func, pc, res)
63}
64