xref: /XiangShan/src/main/scala/xiangshan/backend/decode/FPDecoder.scala (revision b189aafaec05caa2f6081d616f1f0daab1fd2ad8)
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}
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    // scalar cvt inst
47    FCVT_W_S, FCVT_WU_S, FCVT_L_S, FCVT_LU_S,
48    FCVT_W_D, FCVT_WU_D, FCVT_L_D, FCVT_LU_D, FCVT_S_D, FCVT_D_S,
49    FCVT_S_H, FCVT_H_S, FCVT_H_D, FCVT_D_H,
50    FMV_X_W, FMV_X_D, FMV_X_H,
51  )
52  val isFpToVecInst = fpToVecInsts.map(io.instr === _).reduce(_ || _)
53  val isFP32Instrs = Seq(
54    FADD_S, FSUB_S, FEQ_S, FLT_S, FLE_S, FMIN_S, FMAX_S,
55    FMUL_S, FDIV_S, FSQRT_S,
56    FMADD_S, FMSUB_S, FNMADD_S, FNMSUB_S,
57    FCLASS_S, FSGNJ_S, FSGNJX_S, FSGNJN_S,
58  )
59  val isFP32Instr = isFP32Instrs.map(io.instr === _).reduce(_ || _)
60  val isFP64Instrs = Seq(
61    FADD_D, FSUB_D, FEQ_D, FLT_D, FLE_D, FMIN_D, FMAX_D,
62    FMUL_D, FDIV_D, FSQRT_D,
63    FMADD_D, FMSUB_D, FNMADD_D, FNMSUB_D,
64    FCLASS_D, FSGNJ_D, FSGNJX_D, FSGNJN_D,
65  )
66  val isFP64Instr = isFP64Instrs.map(io.instr === _).reduce(_ || _)
67  // scalar cvt inst
68  val isSew2Cvts = Seq(
69    FCVT_W_S, FCVT_WU_S, FCVT_L_S, FCVT_LU_S,
70    FCVT_W_D, FCVT_WU_D, FCVT_S_D, FCVT_D_S,
71    FMV_X_W,
72  )
73  /*
74  The optype for FCVT_D_H and FCVT_H_D is the same,
75  so the two instructions are distinguished by sew.
76  FCVT_H_D:VSew.e64
77  FCVT_D_H:VSew.e16
78   */
79  val isSew2Cvth = Seq(
80    FCVT_S_H, FCVT_H_S, FCVT_D_H,
81    FMV_X_H,
82  )
83  val isSew2Cvt32 = isSew2Cvts.map(io.instr === _).reduce(_ || _)
84  val isSew2Cvt16 = isSew2Cvth.map(io.instr === _).reduce(_ || _)
85  val isLmulMf4Cvts = Seq(
86    FCVT_W_S, FCVT_WU_S,
87    FMV_X_W,
88  )
89  val isLmulMf4Cvt = isLmulMf4Cvts.map(io.instr === _).reduce(_ || _)
90  val needReverseInsts = Seq(
91    FADD_S, FSUB_S, FADD_D, FSUB_D,
92    FEQ_S, FLT_S, FLE_S, FEQ_D, FLT_D, FLE_D,
93    FMIN_S, FMAX_S, FMIN_D, FMAX_D,
94    FMUL_S, FMUL_D,
95    FDIV_S, FDIV_D, FSQRT_S, FSQRT_D,
96    FMADD_S, FMSUB_S, FNMADD_S, FNMSUB_S, FMADD_D, FMSUB_D, FNMADD_D, FNMSUB_D,
97    FCLASS_S, FCLASS_D, FSGNJ_S, FSGNJ_D, FSGNJX_S, FSGNJX_D, FSGNJN_S, FSGNJN_D,
98  )
99  val needReverseInst = needReverseInsts.map(_ === inst.ALL).reduce(_ || _)
100  io.vpuCtrl := 0.U.asTypeOf(io.vpuCtrl)
101  io.vpuCtrl.fpu.isFpToVecInst := isFpToVecInst
102  io.vpuCtrl.fpu.isFP32Instr   := isFP32Instr
103  io.vpuCtrl.fpu.isFP64Instr   := isFP64Instr
104  io.vpuCtrl.vill  := false.B
105  io.vpuCtrl.vma   := true.B
106  io.vpuCtrl.vta   := true.B
107  io.vpuCtrl.vsew  := Mux(isFP32Instr || isSew2Cvt32, VSew.e32, Mux(isSew2Cvt16, VSew.e16, VSew.e64))
108  io.vpuCtrl.vlmul := Mux(isFP32Instr || isLmulMf4Cvt, VLmul.mf4, VLmul.mf2)
109  io.vpuCtrl.vm    := inst.VM
110  io.vpuCtrl.nf    := inst.NF
111  io.vpuCtrl.veew := inst.WIDTH
112  io.vpuCtrl.isReverse := needReverseInst
113  io.vpuCtrl.isExt     := false.B
114  io.vpuCtrl.isNarrow  := false.B
115  io.vpuCtrl.isDstMask := false.B
116  io.vpuCtrl.isOpMask  := false.B
117  io.vpuCtrl.isDependOldvd := false.B
118  io.vpuCtrl.isWritePartVd := false.B
119}
120
121
122class FPDecoder(implicit p: Parameters) extends XSModule{
123  val io = IO(new Bundle() {
124    val instr = Input(UInt(32.W))
125    val fpCtrl = Output(new FPUCtrlSignals)
126  })
127
128  private val inst: XSInstBitFields = io.instr.asTypeOf(new XSInstBitFields)
129
130  def X = BitPat("b?")
131  def N = BitPat("b0")
132  def Y = BitPat("b1")
133  val s = BitPat(FPU.S(0))
134  val d = BitPat(FPU.D(0))
135  val i = BitPat(FPU.D(0))
136
137  val default = List(X,X,X,N,N,N,X,X,X)
138
139  // isAddSub tagIn tagOut fromInt wflags fpWen div sqrt fcvt
140  val single: Array[(BitPat, List[BitPat])] = Array(
141    // IntToFP
142    FMV_W_X  -> List(N,i,s,Y,N,Y,N,N,N),
143    FCVT_S_W -> List(N,i,s,Y,Y,Y,N,N,Y),
144    FCVT_S_WU-> List(N,i,s,Y,Y,Y,N,N,Y),
145    FCVT_S_L -> List(N,i,s,Y,Y,Y,N,N,Y),
146    FCVT_S_LU-> List(N,i,s,Y,Y,Y,N,N,Y),
147    // FPToInt
148    FMV_X_W  -> List(N,d,i,N,N,N,N,N,N), // dont box result of fmv.fp.int
149    FCLASS_S -> List(N,s,i,N,N,N,N,N,N),
150    FCVT_W_S -> List(N,s,i,N,Y,N,N,N,Y),
151    FCVT_WU_S-> List(N,s,i,N,Y,N,N,N,Y),
152    FCVT_L_S -> List(N,s,i,N,Y,N,N,N,Y),
153    FCVT_LU_S-> List(N,s,i,N,Y,N,N,N,Y),
154    FEQ_S    -> List(N,s,i,N,Y,N,N,N,N),
155    FLT_S    -> List(N,s,i,N,Y,N,N,N,N),
156    FLE_S    -> List(N,s,i,N,Y,N,N,N,N),
157    // FPToFP
158    FSGNJ_S  -> List(N,s,s,N,N,Y,N,N,N),
159    FSGNJN_S -> List(N,s,s,N,N,Y,N,N,N),
160    FSGNJX_S -> List(N,s,s,N,N,Y,N,N,N),
161    FMIN_S   -> List(N,s,s,N,Y,Y,N,N,N),
162    FMAX_S   -> List(N,s,s,N,Y,Y,N,N,N),
163    FADD_S   -> List(Y,s,s,N,Y,Y,N,N,N),
164    FSUB_S   -> List(Y,s,s,N,Y,Y,N,N,N),
165    FMUL_S   -> List(N,s,s,N,Y,Y,N,N,N),
166    FMADD_S  -> List(N,s,s,N,Y,Y,N,N,N),
167    FMSUB_S  -> List(N,s,s,N,Y,Y,N,N,N),
168    FNMADD_S -> List(N,s,s,N,Y,Y,N,N,N),
169    FNMSUB_S -> List(N,s,s,N,Y,Y,N,N,N),
170    FDIV_S   -> List(N,s,s,N,Y,Y,Y,N,N),
171    FSQRT_S  -> List(N,s,s,N,Y,Y,N,Y,N)
172  )
173
174
175  // isAddSub tagIn tagOut fromInt wflags fpWen div sqrt fcvt
176  val double: Array[(BitPat, List[BitPat])] = Array(
177    FMV_D_X  -> List(N,i,d,Y,N,Y,N,N,N),
178    FCVT_D_W -> List(N,i,d,Y,Y,Y,N,N,Y),
179    FCVT_D_WU-> List(N,i,d,Y,Y,Y,N,N,Y),
180    FCVT_D_L -> List(N,i,d,Y,Y,Y,N,N,Y),
181    FCVT_D_LU-> List(N,i,d,Y,Y,Y,N,N,Y),
182    FMV_X_D  -> List(N,d,i,N,N,N,N,N,N),
183    FCLASS_D -> List(N,d,i,N,N,N,N,N,N),
184    FCVT_W_D -> List(N,d,i,N,Y,N,N,N,Y),
185    FCVT_WU_D-> List(N,d,i,N,Y,N,N,N,Y),
186    FCVT_L_D -> List(N,d,i,N,Y,N,N,N,Y),
187    FCVT_LU_D-> List(N,d,i,N,Y,N,N,N,Y),
188    FCVT_S_D -> List(N,d,s,N,Y,Y,N,N,Y),
189    FCVT_D_S -> List(N,s,d,N,Y,Y,N,N,Y),
190    FEQ_D    -> List(N,d,i,N,Y,N,N,N,N),
191    FLT_D    -> List(N,d,i,N,Y,N,N,N,N),
192    FLE_D    -> List(N,d,i,N,Y,N,N,N,N),
193    FSGNJ_D  -> List(N,d,d,N,N,Y,N,N,N),
194    FSGNJN_D -> List(N,d,d,N,N,Y,N,N,N),
195    FSGNJX_D -> List(N,d,d,N,N,Y,N,N,N),
196    FMIN_D   -> List(N,d,d,N,Y,Y,N,N,N),
197    FMAX_D   -> List(N,d,d,N,Y,Y,N,N,N),
198    FADD_D   -> List(Y,d,d,N,Y,Y,N,N,N),
199    FSUB_D   -> List(Y,d,d,N,Y,Y,N,N,N),
200    FMUL_D   -> List(N,d,d,N,Y,Y,N,N,N),
201    FMADD_D  -> List(N,d,d,N,Y,Y,N,N,N),
202    FMSUB_D  -> List(N,d,d,N,Y,Y,N,N,N),
203    FNMADD_D -> List(N,d,d,N,Y,Y,N,N,N),
204    FNMSUB_D -> List(N,d,d,N,Y,Y,N,N,N),
205    FDIV_D   -> List(N,d,d,N,Y,Y,Y,N,N),
206    FSQRT_D  -> List(N,d,d,N,Y,Y,N,Y,N)
207  )
208
209  val table = single ++ double
210
211  val decoder = DecodeLogic(io.instr, default, table)
212
213  val ctrl = io.fpCtrl
214  val sigs = Seq(
215    ctrl.isAddSub, ctrl.typeTagIn, ctrl.typeTagOut,
216    ctrl.fromInt, ctrl.wflags, ctrl.fpWen,
217    ctrl.div, ctrl.sqrt, ctrl.fcvt
218  )
219  sigs.zip(decoder).foreach({case (s, d) => s := d})
220  ctrl.typ := inst.TYP
221  ctrl.fmt := inst.FMT
222  ctrl.rm := inst.RM
223
224  val fmaTable: Array[(BitPat, List[BitPat])] = Array(
225    FADD_S  -> List(BitPat("b00"),N),
226    FADD_D  -> List(BitPat("b00"),N),
227    FSUB_S  -> List(BitPat("b01"),N),
228    FSUB_D  -> List(BitPat("b01"),N),
229    FMUL_S  -> List(BitPat("b00"),N),
230    FMUL_D  -> List(BitPat("b00"),N),
231    FMADD_S -> List(BitPat("b00"),Y),
232    FMADD_D -> List(BitPat("b00"),Y),
233    FMSUB_S -> List(BitPat("b01"),Y),
234    FMSUB_D -> List(BitPat("b01"),Y),
235    FNMADD_S-> List(BitPat("b11"),Y),
236    FNMADD_D-> List(BitPat("b11"),Y),
237    FNMSUB_S-> List(BitPat("b10"),Y),
238    FNMSUB_D-> List(BitPat("b10"),Y)
239  )
240  val fmaDefault = List(BitPat("b??"), N)
241  Seq(ctrl.fmaCmd, ctrl.ren3).zip(
242    DecodeLogic(io.instr, fmaDefault, fmaTable)
243  ).foreach({
244    case (s, d) => s := d
245  })
246}
247