// Copyright 2024 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// RiscV 32 bit G instruction decoder.
decoder RiscV32G {
  namespace mpact::sim::riscv::encoding;
  opcode_enum = "isa32::OpcodeEnum";
  includes {
    #include "riscv/riscv32g_decoder.h"
  }
  RiscVGInst32;
  RiscVCInst16;
};

#include "riscv_format32.bin_fmt"
#include "riscv_format16.bin_fmt"

instruction group RiscVIInst32 = {RiscVIInstBase32, RiscVIHints32};

instruction group RiscVGInst32 = {
  RiscVIInst32,
  RiscVZifenceiInst32,
  RiscVZicsrInst32,
  RiscVMInst32,
  RiscVAInst32,
  RiscVFInst32,
  RiscVDInst32,
  RiscVPrivInst32
};


instruction group RiscVIInstBase32[32] : Inst32Format {
  // RV32I Base Instruction Set
  lui    : UType  : opcode == 0b011'0111, rd != 0;
  auipc  : UType  : opcode == 0b001'0111, rd != 0;
  jal    : JType  : rd != 0, opcode == 0b110'1111;
  j      : JType  : rd == 0, opcode == 0b110'1111;
  jalr   : IType  : rd != 0, func3 == 0b000, opcode == 0b110'0111;
  jr     : IType  : rd == 0, func3 == 0b000, opcode == 0b110'0111;
  beq    : BType  : func3 == 0b000, opcode == 0b110'0011;
  bne    : BType  : func3 == 0b001, opcode == 0b110'0011;
  blt    : BType  : func3 == 0b100, opcode == 0b110'0011;
  bge    : BType  : func3 == 0b101, opcode == 0b110'0011;
  bltu   : BType  : func3 == 0b110, opcode == 0b110'0011;
  bgeu   : BType  : func3 == 0b111, opcode == 0b110'0011;
  lb     : BType  : func3 == 0b000, opcode == 0b000'0011;
  lh     : BType  : func3 == 0b001, opcode == 0b000'0011;
  lw     : BType  : func3 == 0b010, opcode == 0b000'0011;
  lbu    : BType  : func3 == 0b100, opcode == 0b000'0011;
  lhu    : BType  : func3 == 0b101, opcode == 0b000'0011;
  sb     : SType  : func3 == 0b000, opcode == 0b010'0011;
  sh     : SType  : func3 == 0b001, opcode == 0b010'0011;
  sw     : SType  : func3 == 0b010, opcode == 0b010'0011;
  addi   : IType  : func3 == 0b000, opcode == 0b001'0011, rd != 0;
  nop    : IType  : func3 == 0b000, opcode == 0b001'0011, rd == 0, imm12 == 0, rs1 == 0;
  slti   : IType  : func3 == 0b010, opcode == 0b001'0011, rd != 0;
  sltiu  : IType  : func3 == 0b011, opcode == 0b001'0011, rd != 0;
  xori   : IType  : func3 == 0b100, rd != 0, opcode == 0b001'0011;
  ori    : IType  : func3 == 0b110, rd != 0b00000, opcode == 0b001'0011;
  andi   : IType  : func3 == 0b111, opcode == 0b001'0011, rd != 0;
  slli   : RType  : func7 == 0b000'0000, func3==0b001, opcode == 0b001'0011;
  srli   : RType  : func7 == 0b000'0000, func3==0b101, rd != 0, opcode == 0b001'0011;
  srai   : RType  : func7 == 0b010'0000, func3==0b101, opcode == 0b001'0011;
  add    : RType  : func7 == 0b000'0000, func3==0b000, rd != 0, opcode == 0b011'0011;
  sub     : RType : func7 == 0b010'0000, func3==0b000, rd != 0, opcode == 0b011'0011;
  sll     : RType : func7 == 0b000'0000, func3==0b001, rd != 0, opcode == 0b011'0011;
  slt     : RType : func7 == 0b000'0000, func3==0b010, rd != 0, opcode == 0b011'0011;
  sltu    : RType : func7 == 0b000'0000, func3==0b011, rd != 0, opcode == 0b011'0011;
  xor     : RType : func7 == 0b000'0000, func3==0b100, rd != 0, opcode == 0b011'0011;
  srl     : RType : func7 == 0b000'0000, func3==0b101, rd != 0, opcode == 0b011'0011;
  sra     : RType : func7 == 0b010'0000, func3==0b101, rd != 0, opcode == 0b011'0011;
  or      : RType : func7 == 0b000'0000, func3==0b110, rd != 0, opcode == 0b011'0011;
  and     : RType : func7 == 0b000'0000, func3==0b111, rd != 0, opcode == 0b011'0011;
  fence     : Fence : fm == 0b0000, succ != 0b0000, func3 == 0b000, opcode == 0b000'1111;
  fence_tso : Fence : fm == 0b1000, pred == 0b0011, succ == 0b0011, func3 == 0b000, opcode == 0b000'1111;
  ecall  : Inst32Format : bits == 0b0000'0000'0000'00000'000'00000, opcode == 0b111'0011;
  ebreak : Inst32Format : bits == 0b0000'0000'0001'00000'000'00000, opcode == 0b111'0011;
};

instruction group RiscVZifenceiInst32[32] : Inst32Format {
  // RV32/RV64 Zifencei Standard Extension
  fencei : IType  : func3 == 001, opcode == 0b000'1111;
};

instruction group RiscVZicsrInst32[32] : Inst32Format {
  // RV32/RV64 Zicsr Standard Extension
  csrrw    : IType  : func3 == 0b001, u_imm12 != 0b1100'0000'0000, rd != 0,  opcode == 0b111'0011;
  csrrs    : IType  : func3 == 0b010, rs1 != 0, rd != 0, opcode == 0b111'0011;
  csrrc    : IType  : func3 == 0b011, rs1 != 0, rd != 0, opcode == 0b111'0011;
  csrrs_nr : IType  : func3 == 0b010, rs1 != 0, rd == 0, opcode == 0b111'0011;
  csrrc_nr : IType  : func3 == 0b011, rs1 != 0, rd == 0, opcode == 0b111'0011;
  csrrw_nr : IType  : func3 == 0b001, u_imm12 != 0b1100'0000'0000, rd == 0,  opcode == 0b111'0011;
  csrrs_nw : IType  : func3 == 0b010, rs1 == 0, opcode == 0b111'0011;
  csrrc_nw : IType  : func3 == 0b011, rs1 == 0, opcode == 0b111'0011;
  csrrwi   : IType  : func3 == 0b101, rd != 0,  opcode == 0b111'0011;
  csrrsi   : IType  : func3 == 0b110, rs1 != 0, rd != 0, opcode == 0b111'0011;
  csrrci   : IType  : func3 == 0b111, rs1 != 0, rd != 0, opcode == 0b111'0011;
  csrrsi_nr: IType  : func3 == 0b110, rs1 != 0, rd == 0, opcode == 0b111'0011;
  csrrci_nr: IType  : func3 == 0b111, rs1 != 0, rd == 0, opcode == 0b111'0011;
  csrrwi_nr: IType  : func3 == 0b101, rd == 0,  opcode == 0b111'0011;
  csrrsi_nw: IType  : func3 == 0b110, rs1 == 0, opcode == 0b111'0011;
  csrrci_nw: IType  : func3 == 0b111, rs1 == 0, opcode == 0b111'0011;
  unimp    : IType  : func3 == 0b001, u_imm12 == 0b1100'0000'0000, rs1 == 0, rd == 0, opcode == 0b111'0011;
};

instruction group RiscVMInst32[32] : Inst32Format {
  // RV32M Standard Extension
  mul    : RType  : func7 == 0b000'0001, func3 == 0b000, opcode == 0b011'0011;
  mulh   : RType  : func7 == 0b000'0001, func3 == 0b001, opcode == 0b011'0011;
  mulhsu : RType  : func7 == 0b000'0001, func3 == 0b010, opcode == 0b011'0011;
  mulhu  : RType  : func7 == 0b000'0001, func3 == 0b011, opcode == 0b011'0011;
  div    : RType  : func7 == 0b000'0001, func3 == 0b100, opcode == 0b011'0011;
  divu   : RType  : func7 == 0b000'0001, func3 == 0b101, opcode == 0b011'0011;
  rem    : RType  : func7 == 0b000'0001, func3 == 0b110, opcode == 0b011'0011;
  remu   : RType  : func7 == 0b000'0001, func3 == 0b111, opcode == 0b011'0011;
};

instruction group RiscVAInst32[32] : Inst32Format {
  // RV32A Standard Extension
  lrw       : AType  : func5 == 0b0'0010, rs2 == 0, func3 == 0b010, opcode == 0b010'1111;
  scw       : AType  : func5 == 0b0'0011, func3 == 0b010, opcode == 0b010'1111;
  amoswapw : AType  : func5 == 0b0'0001,  func3 == 0b010, opcode == 0b010'1111;
  amoaddw  : AType  : func5 == 0b0'0000, func3 == 0b010, opcode == 0b010'1111;
  amoxorw  : AType  : func5 == 0b0'0100, func3 == 0b010, opcode == 0b010'1111;
  amoandw  : AType  : func5 == 0b0'1100, func3 == 0b010, opcode == 0b010'1111;
  amoorw   : AType  : func5 == 0b0'1000, func3 == 0b010, opcode == 0b010'1111;
  amominw  : AType  : func5 == 0b1'0000, func3 == 0b010, opcode == 0b010'1111;
  amomaxw  : AType  : func5 == 0b1'0100, func3 == 0b010, opcode == 0b010'1111;
  amominuw : AType  : func5 == 0b1'1000, func3 == 0b010, opcode == 0b010'1111;
  amomaxuw : AType  : func5 == 0b1'1100, func3 == 0b010, opcode == 0b010'1111;
};

instruction group RiscVFInst32[32] : Inst32Format {
  // RV32F Standard Extension
  flw      : IType  : func3 == 0b010, opcode == 0b000'0111;
  fsw      : SType  : func3 == 0b010, opcode == 0b010'0111;
  fmadd_s  : R4Type : func2 == 0b00,  opcode == 0b100'0011;
  fmsub_s  : R4Type : func2 == 0b00,  opcode == 0b100'0111;
  fnmsub_s : R4Type : func2 == 0b00,  opcode == 0b100'1011;
  fnmadd_s : R4Type : func2 == 0b00,  opcode == 0b100'1111;
  fadd_s   : RType  : func7 == 0b000'0000, opcode == 0b101'0011;
  fsub_s   : RType  : func7 == 0b000'0100, opcode == 0b101'0011;
  fmul_s   : RType  : func7 == 0b000'1000, opcode == 0b101'0011;
  fdiv_s   : RType  : func7 == 0b000'1100, opcode == 0b101'0011;
  fsqrt_s  : RType  : func7 == 0b010'1100, rs2 == 0, opcode == 0b101'0011;
  fsgnj_s  : RType  : func7 == 0b001'0000, func3 == 0b000, opcode == 0b101'0011;
  fsgnjn_s : RType  : func7 == 0b001'0000, func3 == 0b001, opcode == 0b101'0011;
  fsgnjx_s : RType  : func7 == 0b001'0000, func3 == 0b010, opcode == 0b101'0011;
  fmin_s   : RType  : func7 == 0b001'0100, func3 == 0b000, opcode == 0b101'0011;
  fmax_s   : RType  : func7 == 0b001'0100, func3 == 0b001, opcode == 0b101'0011;
  fcvt_ws  : RType  : func7 == 0b110'0000, rs2 == 0, opcode == 0b101'0011;
  fcvt_wus : RType  : func7 == 0b110'0000, rs2 == 1, opcode == 0b101'0011;
  fmv_xw   : RType  : func7 == 0b111'0000, rs2 == 0, func3 == 0b000, opcode == 0b101'0011;
  fcmpeq_s : RType  : func7 == 0b101'0000, func3 == 0b010, opcode == 0b101'0011;
  fcmplt_s : RType  : func7 == 0b101'0000, func3 == 0b001, opcode == 0b101'0011;
  fcmple_s : RType  : func7 == 0b101'0000, func3 == 0b000, opcode == 0b101'0011;
  fclass_s : RType  : func7 == 0b111'0000, rs2 == 0, func3 == 0b001, opcode == 0b101'0011;
  fcvt_sw  : RType  : func7 == 0b110'1000, rs2 == 0, opcode == 0b101'0011;
  fcvt_swu : RType  : func7 == 0b110'1000, rs2 == 1, opcode == 0b101'0011;
  fmv_wx   : RType  : func7 == 0b111'1000, rs2 == 0, func3 == 0b000, opcode == 0b101'0011;
};

instruction group RiscVDInst32[32] : Inst32Format {
  // RV32D Standard Extension
  fld      : IType  : func3 == 0b011, opcode == 0b000'0111;
  fsd      : SType  : func3 == 0b011, opcode == 0b010'0111;
  fmadd_d  : R4Type : func2 == 0b01,  opcode == 0b100'0011;
  fmsub_d  : R4Type : func2 == 0b01,  opcode == 0b100'0111;
  fnmsub_d : R4Type : func2 == 0b01,  opcode == 0b100'1011;
  fnmadd_d : R4Type : func2 == 0b01,  opcode == 0b100'1111;
  fadd_d   : RType  : func7 == 0b000'0001, opcode == 0b101'0011;
  fsub_d   : RType  : func7 == 0b000'0101, opcode == 0b101'0011;
  fmul_d   : RType  : func7 == 0b000'1001, opcode == 0b101'0011;
  fdiv_d   : RType  : func7 == 0b000'1101, opcode == 0b101'0011;
  fsqrt_d  : RType  : func7 == 0b010'1101, rs2 == 0, opcode == 0b101'0011;
  fsgnj_d  : RType  : func7 == 0b001'0001, func3 == 0b000, opcode == 0b101'0011;
  fsgnjn_d : RType  : func7 == 0b001'0001, func3 == 0b001, opcode == 0b101'0011;
  fsgnjx_d : RType  : func7 == 0b001'0001, func3 == 0b010, opcode == 0b101'0011;
  fmin_d   : RType  : func7 == 0b001'0101, func3 == 0b000, opcode == 0b101'0011;
  fmax_d   : RType  : func7 == 0b001'0101, func3 == 0b001, opcode == 0b101'0011;
  fcvt_sd  : RType  : func7 == 0b010'0000, rs2 == 1, opcode == 0b101'0011;
  fcvt_ds  : RType   : func7 == 0b010'0001, rs2 == 0, opcode == 0b101'0011;
  fcmpeq_d : RType  : func7 == 0b101'0001, func3 == 0b010, opcode == 0b101'0011;
  fcmplt_d : RType  : func7 == 0b101'0001, func3 == 0b001, opcode == 0b101'0011;
  fcmple_d : RType  : func7 == 0b101'0001, func3 == 0b000, opcode == 0b101'0011;
  fclass_d : RType  : func7 == 0b111'0001, rs2 == 0, func3 == 0b001, opcode == 0b101'0011;
  fcvt_wd  : RType  : func7 == 0b110'0001, rs2 == 0, opcode == 0b101'0011;
  fcvt_wud : RType  : func7 == 0b110'0001, rs2 == 1, opcode == 0b101'0011;
  fcvt_dw  : RType  : func7 == 0b110'1001, rs2 == 0, opcode == 0b101'0011;
  fcvt_dwu : RType  : func7 == 0b110'1001, rs2 == 1, opcode == 0b101'0011;
};

instruction group RiscVPrivInst32[32] : Inst32Format {
  // RiscV32 Privileged instructions.
  uret    : Inst32Format  : bits == 0b000'0000'00010'00000'000'00000, opcode == 0b111'0011;
  sret    : Inst32Format  : bits == 0b000'1000'00010'00000'000'00000, opcode == 0b111'0011;
  mret    : Inst32Format  : bits == 0b001'1000'00010'00000'000'00000, opcode == 0b111'0011;
  wfi     : Inst32Format  : bits == 0b000'1000'00101'00000'000'00000, opcode == 0b111'0011;
  sfence_vma_zz : RType : func7 == 0b000'1001, rs2 == 0, rs1 == 0, func3 == 0, rd == 0, opcode == 0b111'0011;
  sfence_vma_zn : RType : func7 == 0b000'1001, rs2 != 0, rs1 == 0, func3 == 0, rd == 0, opcode == 0b111'0011;
  sfence_vma_nz : RType : func7 == 0b000'1001, rs2 == 0, rs1 != 0, func3 == 0, rd == 0, opcode == 0b111'0011;
  sfence_vma_nn : RType : func7 == 0b000'1001, rs2 != 0, rs1 != 0, func3 == 0, rd == 0, opcode == 0b111'0011;
};

// Encoding for RiscV hint instructions.
instruction group RiscVIHints32[32] : Inst32Format {
  lui_hint: UType      : opcode == 0b011'0111, rd == 0;
  auipc_hint: UType    : opcode == 0b001'0111, rd == 0;
  addi_hint1: IType    : func3 == 0b000, opcode == 0b001'0011, rd == 0, rs1 != 0;
  addi_hint2: IType    : func3 == 0b000, opcode == 0b001'0011, rd == 0, imm12 != 0;
  slti_hint : IType    : func3 == 0b010, opcode == 0b001'0011, rd == 0;
  sltiu_hint: IType    : func3 == 0b011, opcode == 0b001'0011, rd == 0;
  xori_hint: IType     : func3 == 0b100, rd == 0, opcode == 0b001'0011;
  ori_hint: IType      : func3 == 0b110, rd == 0b00000, opcode == 0b001'0011;
  andi_hint: IType     : func3 == 0b111, opcode == 0b001'0011, rd == 0;
  srli_hint: RType     : func7 == 0b000'0000, func3==0b101, rd == 0, opcode == 0b001'0011;
  slt_hint: RType      : func7 == 0b000'0000, func3==0b010, rd == 0, opcode == 0b011'0011;
  slli_semihost: RType : func7 == 0b000'0000, func3==0b001, rd == 0, rs1 == 0, r_uimm5 == 31, opcode == 0b001'0011;
  slli_hint1: RType    : func7 == 0b000'0000, func3==0b001, rd == 0, rs1 != 0, opcode == 0b001'0011;
  slli_hint2: RType    : func7 == 0b000'0000, func3==0b001, rd == 0, r_uimm5 != 31, opcode == 0b001'0011;
  srai_semihost: RType : func7 == 0b010'0000, func3==0b101, rd == 0, rs1 == 0, r_uimm5 == 7, opcode == 0b001'0011;
  srai_hint1:    RType : func7 == 0b010'0000, func3==0b101, rd == 0, rs1 != 0, opcode == 0b001'0011;
  srai_hint2:    RType : func7 == 0b010'0000, func3==0b101, rd == 0, r_uimm5 != 7, opcode == 0b001'0011;
  add_hint1: RType     : func7 == 0b000'0000, func3==0b000, rd == 0, rs1 != 0, opcode == 0b011'0011;
  add_hint2: RType     : func7 == 0b000'0000, func3==0b000, rd == 0, rs1 == 0, rs2 > 5, opcode == 0b011'0011;
  add_hint3: RType     : func7 == 0b000'0000, func3==0b000, rd == 0, rs1 == 0, rs2 < 2, opcode == 0b011'0011;
  sub_hint: RType      : func7 == 0b010'0000, func3==0b000, rd == 0, opcode == 0b011'0011;
  sll_hint: RType      : func7 == 0b000'0000, func3==0b001, rd == 0, opcode == 0b011'0011;
  sltu_hint: RType     : func7 == 0b000'0000, func3==0b011, rd == 0, opcode == 0b011'0011;
  xor_hint: RType      : func7 == 0b000'0000, func3==0b100, rd == 0, opcode == 0b011'0011;
  srl_hint: RType      : func7 == 0b000'0000, func3==0b101, rd == 0, opcode == 0b011'0011;
  sra_hint: RType      : func7 == 0b010'0000, func3==0b101, rd == 0, opcode == 0b011'0011;
  or_hint : RType      : func7 == 0b000'0000, func3==0b110, rd == 0, opcode == 0b011'0011;
  and_hint: RType      : func7 == 0b000'0000, func3==0b111, rd == 0, opcode == 0b011'0011;
  fence_hint1: Fence   : func3==0b000, rd == 0, rs1 != 0, fm == 0, pred == 0, opcode == 0b000'1111;
  fence_hint2: Fence   : func3==0b000, rd == 0, rs1 != 0, fm == 0, succ == 0, opcode == 0b000'1111;
  fence_hint3: Fence   : func3==0b000, rd != 0, rs1 == 0, fm == 0, pred == 0, opcode == 0b000'1111;
  fence_hint4: Fence   : func3==0b000, rd != 0, rs1 == 0, fm == 0, succ == 0, opcode == 0b000'1111;
  fence_hint5: Fence   : func3==0b000, rd == 0, rs1 == 0, fm == 0, pred == 0, succ != 0, opcode == 0b000'1111;
  fence_hint6: Fence   : func3==0b000, rd == 0, rs1 == 0, fm == 0, succ == 0, opcode == 0b000'1111;
  fence_hint7: Fence   : func3==0b000, rd != 0, rs1 == 0, fm == 0, pred != 1, succ == 0, opcode == 0b000'1111;
};

instruction group RiscVCInst16 = {RiscVCInstBase16, RiscVCHints16};

// Compact instruction encodings.
instruction group RiscVCInstBase16[16] : Inst16Format {
  caddi4spn : CIW: func3 == 0b000, op == 0b00, imm8 != 0;
  cfld      : CL : func3 == 0b001, op == 0b00;
  clw       : CL : func3 == 0b010, op == 0b00;
  cflw      : CL : func3 == 0b011, op == 0b00;
  cfsd      : CS : func3 == 0b101, op == 0b00;
  csw       : CS : func3 == 0b110, op == 0b00;
  cfsw      : CS : func3 == 0b111, op == 0b00;
  cnop      : CI : func3 == 0b000, imm1 == 0, rs1 == 0, imm5 == 0, op == 0b01;
  caddi     : CI : func3 == 0b000, imm6 != 0, rd != 0, op == 0b01;
  cjal      : CJ : func3 == 0b001, op == 0b01;
  cli       : CI : func3 == 0b010, rd != 0, op == 0b01;
  caddi16sp : CI : func3 == 0b011, rd == 2, op == 0b01;
  clui      : CI : func3 == 0b011, rd != 0, rd != 2, op == 0b01;
  csrli     : CB : func3 == 0b100, imm3 == 0b000, op == 0b01;
  csrai     : CB : func3 == 0b100, imm3 == 0b001, op == 0b01;
  candi     : CB : func3 == 0b100, func2 == 0b10, op == 0b01;
  csub      : CA : func6 == 0b100'011, func2 == 0b00, op == 0b01;
  cxor      : CA : func6 == 0b100'011, func2 == 0b01, op == 0b01;
  cor       : CA : func6 == 0b100'011, func2 == 0b10, op == 0b01;
  cand      : CA : func6 == 0b100'011, func2 == 0b11, op == 0b01;
  cj        : CJ : func3 == 0b101, op == 0b01;
  cbeqz     : CB : func3 == 0b110, op == 0b01;
  cbnez     : CB : func3 == 0b111, op == 0b01;
  cslli     : CI : func3 == 0b000, imm1 == 0, rs1 != 0, op == 0b10;
  cfldsp    : CI : func3 == 0b001, op == 0b10;
  clwsp     : CI : func3 == 0b010, rd != 0, op == 0b10;
  cflwsp    : CI : func3 == 0b011, op == 0b10;
  cjr       : CR : func4 == 0b1000, rs1 != 0, rs2 == 0, op == 0b10;
  cmv       : CR : func4 == 0b1000, rs1 != 0, rs2 != 0, op == 0b10;
  cebreak   : CR : func4 == 0b1001, rs1 == 0, rs2 == 0, op == 0b10;
  cjalr     : CR : func4 == 0b1001, rs1 != 0, rs2 == 0, op == 0b10;
  cadd      : CR : func4 == 0b1001, rs1 != 0, rs2 != 0, op == 0b10;
  cfsdsp    : CSS: func3 == 0b101, op == 0b10;
  cswsp     : CSS: func3 == 0b110, op == 0b10;
  cfswsp    : CSS: func3 == 0b111, op == 0b10;
  cunimp   : Inst16Format : func3 == 0b000, bits == 0b000'0000'0000, op == 0b00;
};

instruction group RiscVCHints16[16] : Inst16Format {
  cnop_hint : CI : func3 == 0b000, imm6 != 0, rs1 == 0, op == 0b01;
  caddi_hint: CI : func3 == 0b000, imm6 == 0, rd != 0, op == 0b01;
  cli_hint  : CI : func3 == 0b010, rd == 0, op == 0b01;
  clui_hint : CI : func3 == 0b011, rd == 0, imm6 != 0, op == 0b01;
  cmv_hint  : CR : func4 == 0b1000, rs1 == 0, rs2 != 0, op == 0b10;
  cslli_hint: CI : func3 == 0b000, imm6 != 0, rd == 0, op == 0b10;
  cadd_hint : CR : func4 == 0b1001, rs1 == 0, rs2 != 0, rs2 != 2, rs2 != 3, rs2 != 4, rs2 != 5, op == 0b10;
};