xref: /XiangShan/src/main/scala/xiangshan/backend/fu/Jump.scala (revision 039cdc35f5f3b68b6295ec5ace90f22a77322e02)
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.fu
18
19import org.chipsalliance.cde.config.Parameters
20import chisel3._
21import chisel3.util._
22import utility._
23import utils._
24import xiangshan._
25import xiangshan.backend._
26import xiangshan.backend.decode.ImmUnion
27import xiangshan.backend.decode.isa._
28
29trait HasRedirectOut { this: XSModule =>
30  val redirectOutValid = IO(Output(Bool()))
31  val redirectOut = IO(Output(new Redirect))
32}
33
34class JumpDataModule(implicit p: Parameters) extends XSModule {
35  val io = IO(new Bundle() {
36    val src = Input(UInt(XLEN.W))
37    val pc = Input(UInt(XLEN.W)) // sign-ext to XLEN
38    val immMin = Input(UInt(ImmUnion.maxLen.W))
39    val func = Input(FuOpType())
40    val isRVC = Input(Bool())
41    val result, target = Output(UInt(XLEN.W))
42    val isAuipc = Output(Bool())
43  })
44  val (src1, pc, immMin, func, isRVC) = (io.src, io.pc, io.immMin, io.func, io.isRVC)
45
46  val isJalr = JumpOpType.jumpOpisJalr(func)
47  val isAuipc = JumpOpType.jumpOpisAuipc(func)
48  val offset = SignExt(ParallelMux(Seq(
49    isJalr -> ImmUnion.I.toImm32(immMin),
50    isAuipc -> ImmUnion.U.toImm32(immMin),
51    !(isJalr || isAuipc) -> ImmUnion.J.toImm32(immMin)
52  )), XLEN)
53
54  val snpc = pc + Mux(isRVC, 2.U, 4.U)
55  val target = Mux(JumpOpType.jumpOpisJalr(func), src1, pc) + offset // NOTE: src1 is (pc/rf(rs1)), src2 is (offset)
56
57  // RISC-V spec for JALR:
58  // The target address is obtained by adding the sign-extended 12-bit I-immediate to the register rs1,
59  // then setting the least-significant bit of the result to zero.
60  io.target := Cat(target(XLEN - 1, 1), false.B)
61  io.result := Mux(JumpOpType.jumpOpisAuipc(func), target, snpc)
62  io.isAuipc := isAuipc
63}
64