xref: /XiangShan/src/main/scala/xiangshan/backend/decode/FPDecoder.scala (revision 4b0d80d87574e82ba31737496d63ac30bed0d40a)
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.decode
18
19import org.chipsalliance.cde.config.Parameters
20import chisel3._
21import chisel3.util._
22import freechips.rocketchip.rocket.DecodeLogic
23import freechips.rocketchip.rocket.Instructions._
24import xiangshan.backend.decode.isa.bitfield.XSInstBitFields
25import xiangshan.backend.fu.fpu.FPU
26import xiangshan.backend.fu.vector.Bundles.{VSew, VLmul, Category}
27import xiangshan.backend.Bundles.VPUCtrlSignals
28import xiangshan.{FPUCtrlSignals, XSModule}
29
30class FPToVecDecoder(implicit p: Parameters) extends XSModule {
31  val io = IO(new Bundle() {
32    val instr = Input(UInt(32.W))
33    val vpuCtrl = Output(new VPUCtrlSignals)
34  })
35
36  val inst = io.instr.asTypeOf(new XSInstBitFields)
37  val fpToVecInsts = Seq(
38    FADD_S, FSUB_S, FADD_D, FSUB_D,
39    FEQ_S, FLT_S, FLE_S, FEQ_D, FLT_D, FLE_D,
40    FMIN_S, FMAX_S, FMIN_D, FMAX_D,
41    FMUL_S, FMUL_D,
42    FDIV_S, FDIV_D, FSQRT_S, FSQRT_D,
43    FMADD_S, FMSUB_S, FNMADD_S, FNMSUB_S, FMADD_D, FMSUB_D, FNMADD_D, FNMSUB_D,
44    FCLASS_S, FCLASS_D, FSGNJ_S, FSGNJ_D, FSGNJX_S, FSGNJX_D, FSGNJN_S, FSGNJN_D,
45  )
46  val isFpToVecInst = fpToVecInsts.map(io.instr === _).reduce(_ || _)
47  val isFP32Instrs = Seq(
48    FADD_S, FSUB_S, FEQ_S, FLT_S, FLE_S, FMIN_S, FMAX_S,
49    FMUL_S, FDIV_S, FSQRT_S,
50    FMADD_S, FMSUB_S, FNMADD_S, FNMSUB_S,
51    FCLASS_S, FSGNJ_S, FSGNJX_S, FSGNJN_S,
52  )
53  val isFP32Instr = isFP32Instrs.map(io.instr === _).reduce(_ || _)
54  val isFP64Instrs = Seq(
55    FADD_D, FSUB_D, FEQ_D, FLT_D, FLE_D, FMIN_D, FMAX_D,
56    FMUL_D, FDIV_D, FSQRT_D,
57    FMADD_D, FMSUB_D, FNMADD_D, FNMSUB_D,
58    FCLASS_D, FSGNJ_D, FSGNJX_D, FSGNJN_D,
59  )
60  val isFP64Instr = isFP64Instrs.map(io.instr === _).reduce(_ || _)
61  val needReverseInsts = fpToVecInsts
62  val needReverseInst = needReverseInsts.map(_ === inst.ALL).reduce(_ || _)
63  io.vpuCtrl := 0.U.asTypeOf(io.vpuCtrl)
64  io.vpuCtrl.fpu.isFpToVecInst := isFpToVecInst
65  io.vpuCtrl.fpu.isFP32Instr   := isFP32Instr
66  io.vpuCtrl.fpu.isFP64Instr   := isFP64Instr
67  io.vpuCtrl.vill  := false.B
68  io.vpuCtrl.vma   := true.B
69  io.vpuCtrl.vta   := true.B
70  io.vpuCtrl.vsew  := Mux(isFP32Instr, VSew.e32, VSew.e64)
71  io.vpuCtrl.vlmul := Mux(isFP32Instr, VLmul.mf4, VLmul.mf2)
72  io.vpuCtrl.vm    := inst.VM
73  io.vpuCtrl.nf    := inst.NF
74  io.vpuCtrl.needScalaSrc := Category.needScalaSrc(inst.VCATEGORY)
75  io.vpuCtrl.permImmTruncate := Category.permImmTruncate(inst.VCATEGORY)
76  io.vpuCtrl.isReverse := needReverseInst
77  io.vpuCtrl.isExt     := false.B
78  io.vpuCtrl.isNarrow  := false.B
79  io.vpuCtrl.isDstMask := false.B
80  io.vpuCtrl.isOpMask  := false.B
81}
82
83
84class FPDecoder(implicit p: Parameters) extends XSModule{
85  val io = IO(new Bundle() {
86    val instr = Input(UInt(32.W))
87    val fpCtrl = Output(new FPUCtrlSignals)
88  })
89
90  private val inst: XSInstBitFields = io.instr.asTypeOf(new XSInstBitFields)
91
92  def X = BitPat("b?")
93  def N = BitPat("b0")
94  def Y = BitPat("b1")
95  val s = BitPat(FPU.S)
96  val d = BitPat(FPU.D)
97  val i = BitPat(FPU.D)
98
99  val default = List(X,X,X,N,N,N,X,X,X)
100
101  // isAddSub tagIn tagOut fromInt wflags fpWen div sqrt fcvt
102  val single: Array[(BitPat, List[BitPat])] = Array(
103    // IntToFP
104    FMV_W_X  -> List(N,i,s,Y,N,Y,N,N,N),
105    FCVT_S_W -> List(N,i,s,Y,Y,Y,N,N,Y),
106    FCVT_S_WU-> List(N,i,s,Y,Y,Y,N,N,Y),
107    FCVT_S_L -> List(N,i,s,Y,Y,Y,N,N,Y),
108    FCVT_S_LU-> List(N,i,s,Y,Y,Y,N,N,Y),
109    // FPToInt
110    FMV_X_W  -> List(N,d,i,N,N,N,N,N,N), // dont box result of fmv.fp.int
111    FCLASS_S -> List(N,s,i,N,N,N,N,N,N),
112    FCVT_W_S -> List(N,s,i,N,Y,N,N,N,Y),
113    FCVT_WU_S-> List(N,s,i,N,Y,N,N,N,Y),
114    FCVT_L_S -> List(N,s,i,N,Y,N,N,N,Y),
115    FCVT_LU_S-> List(N,s,i,N,Y,N,N,N,Y),
116    FEQ_S    -> List(N,s,i,N,Y,N,N,N,N),
117    FLT_S    -> List(N,s,i,N,Y,N,N,N,N),
118    FLE_S    -> List(N,s,i,N,Y,N,N,N,N),
119    // FPToFP
120    FSGNJ_S  -> List(N,s,s,N,N,Y,N,N,N),
121    FSGNJN_S -> List(N,s,s,N,N,Y,N,N,N),
122    FSGNJX_S -> List(N,s,s,N,N,Y,N,N,N),
123    FMIN_S   -> List(N,s,s,N,Y,Y,N,N,N),
124    FMAX_S   -> List(N,s,s,N,Y,Y,N,N,N),
125    FADD_S   -> List(Y,s,s,N,Y,Y,N,N,N),
126    FSUB_S   -> List(Y,s,s,N,Y,Y,N,N,N),
127    FMUL_S   -> List(N,s,s,N,Y,Y,N,N,N),
128    FMADD_S  -> List(N,s,s,N,Y,Y,N,N,N),
129    FMSUB_S  -> List(N,s,s,N,Y,Y,N,N,N),
130    FNMADD_S -> List(N,s,s,N,Y,Y,N,N,N),
131    FNMSUB_S -> List(N,s,s,N,Y,Y,N,N,N),
132    FDIV_S   -> List(N,s,s,N,Y,Y,Y,N,N),
133    FSQRT_S  -> List(N,s,s,N,Y,Y,N,Y,N)
134  )
135
136
137  // isAddSub tagIn tagOut fromInt wflags fpWen div sqrt fcvt
138  val double: Array[(BitPat, List[BitPat])] = Array(
139    FMV_D_X  -> List(N,i,d,Y,N,Y,N,N,N),
140    FCVT_D_W -> List(N,i,d,Y,Y,Y,N,N,Y),
141    FCVT_D_WU-> List(N,i,d,Y,Y,Y,N,N,Y),
142    FCVT_D_L -> List(N,i,d,Y,Y,Y,N,N,Y),
143    FCVT_D_LU-> List(N,i,d,Y,Y,Y,N,N,Y),
144    FMV_X_D  -> List(N,d,i,N,N,N,N,N,N),
145    FCLASS_D -> List(N,d,i,N,N,N,N,N,N),
146    FCVT_W_D -> List(N,d,i,N,Y,N,N,N,Y),
147    FCVT_WU_D-> List(N,d,i,N,Y,N,N,N,Y),
148    FCVT_L_D -> List(N,d,i,N,Y,N,N,N,Y),
149    FCVT_LU_D-> List(N,d,i,N,Y,N,N,N,Y),
150    FCVT_S_D -> List(N,d,s,N,Y,Y,N,N,Y),
151    FCVT_D_S -> List(N,s,d,N,Y,Y,N,N,Y),
152    FEQ_D    -> List(N,d,i,N,Y,N,N,N,N),
153    FLT_D    -> List(N,d,i,N,Y,N,N,N,N),
154    FLE_D    -> List(N,d,i,N,Y,N,N,N,N),
155    FSGNJ_D  -> List(N,d,d,N,N,Y,N,N,N),
156    FSGNJN_D -> List(N,d,d,N,N,Y,N,N,N),
157    FSGNJX_D -> List(N,d,d,N,N,Y,N,N,N),
158    FMIN_D   -> List(N,d,d,N,Y,Y,N,N,N),
159    FMAX_D   -> List(N,d,d,N,Y,Y,N,N,N),
160    FADD_D   -> List(Y,d,d,N,Y,Y,N,N,N),
161    FSUB_D   -> List(Y,d,d,N,Y,Y,N,N,N),
162    FMUL_D   -> List(N,d,d,N,Y,Y,N,N,N),
163    FMADD_D  -> List(N,d,d,N,Y,Y,N,N,N),
164    FMSUB_D  -> List(N,d,d,N,Y,Y,N,N,N),
165    FNMADD_D -> List(N,d,d,N,Y,Y,N,N,N),
166    FNMSUB_D -> List(N,d,d,N,Y,Y,N,N,N),
167    FDIV_D   -> List(N,d,d,N,Y,Y,Y,N,N),
168    FSQRT_D  -> List(N,d,d,N,Y,Y,N,Y,N)
169  )
170
171  val table = single ++ double
172
173  val decoder = DecodeLogic(io.instr, default, table)
174
175  val ctrl = io.fpCtrl
176  val sigs = Seq(
177    ctrl.isAddSub, ctrl.typeTagIn, ctrl.typeTagOut,
178    ctrl.fromInt, ctrl.wflags, ctrl.fpWen,
179    ctrl.div, ctrl.sqrt, ctrl.fcvt
180  )
181  sigs.zip(decoder).foreach({case (s, d) => s := d})
182  ctrl.typ := inst.TYP
183  ctrl.fmt := inst.FMT
184  ctrl.rm := inst.RM
185
186  val fmaTable: Array[(BitPat, List[BitPat])] = Array(
187    FADD_S  -> List(BitPat("b00"),N),
188    FADD_D  -> List(BitPat("b00"),N),
189    FSUB_S  -> List(BitPat("b01"),N),
190    FSUB_D  -> List(BitPat("b01"),N),
191    FMUL_S  -> List(BitPat("b00"),N),
192    FMUL_D  -> List(BitPat("b00"),N),
193    FMADD_S -> List(BitPat("b00"),Y),
194    FMADD_D -> List(BitPat("b00"),Y),
195    FMSUB_S -> List(BitPat("b01"),Y),
196    FMSUB_D -> List(BitPat("b01"),Y),
197    FNMADD_S-> List(BitPat("b11"),Y),
198    FNMADD_D-> List(BitPat("b11"),Y),
199    FNMSUB_S-> List(BitPat("b10"),Y),
200    FNMSUB_D-> List(BitPat("b10"),Y)
201  )
202  val fmaDefault = List(BitPat("b??"), N)
203  Seq(ctrl.fmaCmd, ctrl.ren3).zip(
204    DecodeLogic(io.instr, fmaDefault, fmaTable)
205  ).foreach({
206    case (s, d) => s := d
207  })
208}
209