xref: /gem5/src/arch/arm/isa/decoder/arm.isa

// -*- mode:c++ -*-

// Copyright (c) 2010 ARM Limited
// All rights reserved
//
// The license below extends only to copyright in the software and shall
// not be construed as granting a license to any other intellectual
// property including but not limited to intellectual property relating
// to a hardware implementation of the functionality of the software
// licensed hereunder.  You may use the software subject to the license
// terms below provided that you ensure that this notice is replicated
// unmodified and in its entirety in all distributions of the software,
// modified or unmodified, in source code or in binary form.
//
// Copyright (c) 2007-2008 The Florida State University
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met: redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer;
// redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution;
// neither the name of the copyright holders nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Authors: Stephen Hines

////////////////////////////////////////////////////////////////////
//
// The actual ARM ISA decoder
// --------------------------
// The following instructions are specified in the ARM ISA
// Specification. Decoding closely follows the style specified
// in the ARM ISA specification document starting with Table B.1 or 3-1
//
//

0: decode ENCODING {
format DataOp {
    0x0: decode SEVEN_AND_FOUR {
        1: decode MISC_OPCODE {
            0x9: decode PREPOST {
                0: decode OPCODE {
                    0x0: mul({{ Rn = resTemp = Rm * Rs; }}, none);
                    0x1: mla({{ Rn = resTemp = (Rm * Rs) + Rd; }}, none);
                    0x2: WarnUnimpl::umall();
                    0x4: umull({{
                        resTemp = ((uint64_t)Rm)*((uint64_t)Rs);
                        Rd = (uint32_t)(resTemp & 0xffffffff);
                        Rn = (uint32_t)(resTemp >> 32);
                    }}, llbit);
                    0x5: smlal({{
                        resTemp = ((int64_t)Rm) * ((int64_t)Rs);
                        resTemp += (((uint64_t)Rn) << 32) | ((uint64_t)Rd);
                        Rd = (uint32_t)(resTemp & 0xffffffff);
                        Rn = (uint32_t)(resTemp >> 32);
                    }}, llbit);
                    0x6: smull({{
                        resTemp = ((int64_t)(int32_t)Rm)*
                                  ((int64_t)(int32_t)Rs);
                        Rd = (int32_t)(resTemp & 0xffffffff);
                        Rn = (int32_t)(resTemp >> 32);
                    }}, llbit);
                    0x7: umlal({{
                        resTemp = ((uint64_t)Rm)*((uint64_t)Rs);
                        resTemp += ((uint64_t)Rn << 32)+((uint64_t)Rd);
                        Rd = (uint32_t)(resTemp & 0xffffffff);
                        Rn = (uint32_t)(resTemp >> 32);
                    }}, llbit);
                }
                1: decode PUBWL {
                    0x10: WarnUnimpl::swp();
                    0x14: WarnUnimpl::swpb();
                    0x18: WarnUnimpl::strex();
                    0x19: WarnUnimpl::ldrex();
                }
            }
            format AddrMode3 {
                0xb: strh_ldrh(store, {{ Mem.uh = Rd; }},
                               load,  {{ Rd = Mem.uh; }});
                0xd: ldrd_ldrsb(load, {{ Rde = bits(Mem.ud, 31, 0);
                                         Rdo = bits(Mem.ud, 63, 32); }},
                                load, {{ Rd = Mem.sb; }});
                0xf: strd_ldrsh(store, {{ Mem.ud = (Rde.ud & mask(32)) |
                                                   (Rdo.ud << 32); }},
                                load,  {{ Rd = Mem.sh; }});
            }
        }
        0: decode IS_MISC {
            0: decode OPCODE {
                0x0: and({{ Rd = resTemp = Rn & op2; }});
                0x1: eor({{ Rd = resTemp = Rn ^ op2; }});
                0x2: sub({{ Rd = resTemp = Rn - op2; }}, sub);
                0x3: rsb({{ Rd = resTemp = op2 - Rn; }}, rsb);
                0x4: add({{ Rd = resTemp = Rn + op2; }}, add);
                0x5: adc({{ Rd = resTemp = Rn + op2 + CondCodes<29:>; }}, add);
                0x6: sbc({{ Rd = resTemp = Rn - op2 - !CondCodes<29:>; }}, sub);
                0x7: rsc({{ Rd = resTemp = op2 - Rn - !CondCodes<29:>; }}, rsb);
                0x8: tst({{ resTemp = Rn & op2; }});
                0x9: teq({{ resTemp = Rn ^ op2; }});
                0xa: cmp({{ resTemp = Rn - op2; }}, sub);
                0xb: cmn({{ resTemp = Rn + op2; }}, add);
                0xc: orr({{ Rd = resTemp = Rn | op2; }});
                0xd: mov({{ Rd = resTemp = op2; }});
                0xe: bic({{ Rd = resTemp = Rn & ~op2; }});
                0xf: mvn({{ Rd = resTemp = ~op2; }});
            }
            1: decode MISC_OPCODE {
                0x0: decode OPCODE {
                    0x8: PredOp::mrs_cpsr({{
                        Rd = (Cpsr | CondCodes) & 0xF8FF03DF;
                    }});
                    0x9: decode USEIMM {
                        // The mask field is the same as the RN index.
                        0: PredOp::msr_cpsr_reg({{
                            uint32_t newCpsr =
                                cpsrWriteByInstr(Cpsr | CondCodes,
                                                 Rm, RN, false);
                            Cpsr = ~CondCodesMask & newCpsr;
                            CondCodes = CondCodesMask & newCpsr;
                        }});
                        1: PredImmOp::msr_cpsr_imm({{
                            uint32_t newCpsr =
                                cpsrWriteByInstr(Cpsr | CondCodes,
                                                 rotated_imm, RN, false);
                            Cpsr = ~CondCodesMask & newCpsr;
                            CondCodes = CondCodesMask & newCpsr;
                        }});
                    }
                    0xa: PredOp::mrs_spsr({{ Rd = Spsr; }});
                    0xb: decode USEIMM {
                        // The mask field is the same as the RN index.
                        0: PredOp::msr_spsr_reg({{
                            Spsr = spsrWriteByInstr(Spsr, Rm, RN, false);
                        }});
                        1: PredImmOp::msr_spsr_imm({{
                            Spsr = spsrWriteByInstr(Spsr, rotated_imm,
                                                    RN, false);
                        }});
                    }
                }
                0x1: decode OPCODE {
                    0x9: BranchExchange::bx({{ }});
                    0xb: PredOp::clz({{
                        Rd = ((Rm == 0) ? 32 : (31 - findMsbSet(Rm)));
                    }});
                }
                0x2: decode OPCODE {
                    0x9: WarnUnimpl::bxj();
                }
                0x3: decode OPCODE {
                    0x9: BranchExchange::blx({{ }}, Link);
                }
                0x5: decode OPCODE {
                    0x8: WarnUnimpl::qadd();
                    0x9: WarnUnimpl::qsub();
                    0xa: WarnUnimpl::qdadd();
                    0xb: WarnUnimpl::qdsub();
                }
                0x8: decode OPCODE {
                    0x8: smlabb({{ Rn = resTemp = sext<16>(Rm<15:0>) * sext<16>(Rs<15:0>) + Rd; }}, overflow);
                    0x9: WarnUnimpl::smlalbb();
                    0xa: WarnUnimpl::smlawb();
                    0xb: smulbb({{ Rn = resTemp = sext<16>(Rm<15:0>) * sext<16>(Rs<15:0>); }}, none);
                }
                0xa: decode OPCODE {
                    0x8: smlatb({{ Rn = resTemp = sext<16>(Rm<31:16>) * sext<16>(Rs<15:0>) + Rd; }}, overflow);
                    0x9: smulwb({{
                        Rn = resTemp = bits(sext<32>(Rm) * sext<16>(Rs<15:0>), 47, 16);
                    }}, none);
                    0xa: WarnUnimpl::smlaltb();
                    0xb: smultb({{ Rn = resTemp = sext<16>(Rm<31:16>) * sext<16>(Rs<15:0>); }}, none);
                }
                0xc: decode OPCODE {
                    0x8: smlabt({{ Rn = resTemp = sext<16>(Rm<15:0>) * sext<16>(Rs<31:16>) + Rd; }}, overflow);
                    0x9: WarnUnimpl::smlawt();
                    0xa: WarnUnimpl::smlalbt();
                    0xb: smulbt({{ Rn = resTemp = sext<16>(Rm<15:0>) * sext<16>(Rs<31:16>); }}, none);
                }
                0xe: decode OPCODE {
                    0x8: smlatt({{ Rn = resTemp = sext<16>(Rm<31:16>) * sext<16>(Rs<31:16>) + Rd; }}, overflow);
                    0x9: smulwt({{
                        Rn = resTemp = bits(sext<32>(Rm) * sext<16>(Rs<31:16>), 47, 16);
                    }}, none);
                    0xa: WarnUnimpl::smlaltt();
                    0xb: smultt({{ Rn = resTemp = sext<16>(Rm<31:16>) * sext<16>(Rs<31:16>); }}, none);
                }
            }
        }
    }
    0x1: decode IS_MISC {
        0: decode OPCODE {
            format DataImmOp {
                0x0: andi({{ Rd = resTemp = Rn & rotated_imm; }});
                0x1: eori({{ Rd = resTemp = Rn ^ rotated_imm; }});
                0x2: subi({{ Rd = resTemp = Rn - rotated_imm; }}, sub);
                0x3: rsbi({{ Rd = resTemp = rotated_imm - Rn; }}, rsb);
                0x4: addi({{ Rd = resTemp = Rn + rotated_imm; }}, add);
                0x5: adci({{
                    Rd = resTemp = Rn + rotated_imm + CondCodes<29:>;
                }}, add);
                0x6: sbci({{
                    Rd = resTemp = Rn -rotated_imm - !CondCodes<29:>;
                }}, sub);
                0x7: rsci({{
                    Rd = resTemp = rotated_imm - Rn - !CondCodes<29:>;
                }}, rsb);
                0x8: tsti({{ resTemp = Rn & rotated_imm; }});
                0x9: teqi({{ resTemp = Rn ^ rotated_imm; }});
                0xa: cmpi({{ resTemp = Rn - rotated_imm; }}, sub);
                0xb: cmni({{ resTemp = Rn + rotated_imm; }}, add);
                0xc: orri({{ Rd = resTemp = Rn | rotated_imm; }});
                0xd: movi({{ Rd = resTemp = rotated_imm; }});
                0xe: bici({{ Rd = resTemp = Rn & ~rotated_imm; }});
                0xf: mvni({{ Rd = resTemp = ~rotated_imm; }});
            }
        }
        1: decode OPCODE {
            // The following two instructions aren't supposed to be defined
            0x8: DataOp::movw({{ Rd = IMMED_11_0 | (RN << 12) ; }});
            0x9: decode RN {
                0: decode IMM {
                    0: PredImmOp::nop({{ ; }});
                    1: WarnUnimpl::yield();
                    2: WarnUnimpl::wfe();
                    3: WarnUnimpl::wfi();
                    4: WarnUnimpl::sev();
                }
                default: PredImmOp::msr_i_cpsr({{
                            uint32_t newCpsr =
                                cpsrWriteByInstr(Cpsr | CondCodes,
                                                 rotated_imm, RN, false);
                            Cpsr = ~CondCodesMask & newCpsr;
                            CondCodes = CondCodesMask & newCpsr;
                }});
            }
            0xa: PredOp::movt({{ Rd = IMMED_11_0 << 16 | RN << 28 | Rd<15:0>; }});
            0xb: PredImmOp::msr_i_spsr({{
                       Spsr = spsrWriteByInstr(Spsr, rotated_imm, RN, false);
            }});
        }
    }
    0x2: AddrMode2::addrMode2(Disp, disp);
    0x3: decode OPCODE_4 {
        0: AddrMode2::addrMode2(Shift, Rm_Imm);
        1: decode MEDIA_OPCODE {
            0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7: WarnUnimpl::parallel_add_subtract_instructions();
            0x8: decode MISC_OPCODE {
                0x1, 0x9: WarnUnimpl::pkhbt();
                0x7: WarnUnimpl::sxtab16();
                0xb: WarnUnimpl::sel();
                0x5, 0xd: WarnUnimpl::pkhtb();
                0x3: WarnUnimpl::sign_zero_extend_add();
            }
            0xa, 0xb: decode SHIFT {
                0x0, 0x2: WarnUnimpl::ssat();
                0x1: WarnUnimpl::ssat16();
            }
            0xe, 0xf: decode SHIFT {
                0x0, 0x2: WarnUnimpl::usat();
                0x1: WarnUnimpl::usat16();
            }
            0x10: decode RN {
                0xf: decode MISC_OPCODE {
                    0x1: WarnUnimpl::smuad();
                    0x3: WarnUnimpl::smuadx();
                    0x5: WarnUnimpl::smusd();
                    0x7: WarnUnimpl::smusdx();
                }
                default: decode MISC_OPCODE {
                    0x1: WarnUnimpl::smlad();
                    0x3: WarnUnimpl::smladx();
                    0x5: WarnUnimpl::smlsd();
                    0x7: WarnUnimpl::smlsdx();
                }
            }
            0x14: decode MISC_OPCODE {
                0x1: WarnUnimpl::smlald();
                0x3: WarnUnimpl::smlaldx();
                0x5: WarnUnimpl::smlsld();
                0x7: WarnUnimpl::smlsldx();
            }
            0x15: decode RN {
                0xf: decode MISC_OPCODE {
                    0x1: WarnUnimpl::smmul();
                    0x3: WarnUnimpl::smmulr();
                }
                default: decode MISC_OPCODE {
                    0x1: WarnUnimpl::smmla();
                    0x3: WarnUnimpl::smmlar();
                    0xd: WarnUnimpl::smmls();
                    0xf: WarnUnimpl::smmlsr();
                }
            }
            0x18: decode RN {
                0xf: WarnUnimpl::usada8();
                default: WarnUnimpl::usad8();
            }
        }
    }
    0x4: decode PUSWL {
        // Right now we only handle cases when S (PSRUSER) is not set
        default: ArmMacroStore::ldmstm({{ }});
    }
    0x5: decode OPCODE_24 {
        // Branch (and Link) Instructions
        0: Branch::b({{ }});
        1: Branch::bl({{ }}, Link);
    }
    0x6: decode CPNUM {
        0x1: decode PUNWL {
            0x02,0x0a: decode OPCODE_15 {
                0: ArmStoreMemory::stfs_({{ Mem.sf = Fd.sf;
                                            Rn = Rn + disp8; }},
                    {{ EA = Rn; }});
                1: ArmMacroFPAOp::stfd_({{ }});
            }
            0x03,0x0b: decode OPCODE_15 {
                0: ArmLoadMemory::ldfs_({{ Fd.sf = Mem.sf;
                                           Rn = Rn + disp8; }},
                    {{ EA = Rn; }});
                1: ArmMacroFPAOp::ldfd_({{ }});
            }
            0x06,0x0e: decode OPCODE_15 {
                0: ArmMacroFPAOp::stfe_nw({{ }});
            }
            0x07,0x0f: decode OPCODE_15 {
                0: ArmMacroFPAOp::ldfe_nw({{ }});
            }
            0x10,0x18: decode OPCODE_15 {
                0: ArmStoreMemory::stfs_p({{ Mem.sf = Fd.sf; }},
                    {{ EA = Rn + disp8; }});
                1: ArmMacroFPAOp::stfd_p({{ }});
            }
            0x11,0x19: decode OPCODE_15 {
                0: ArmLoadMemory::ldfs_p({{ Fd.sf = Mem.sf; }},
                    {{ EA = Rn + disp8; }});
                1: ArmMacroFPAOp::ldfd_p({{ }});
            }
            0x12,0x1a: decode OPCODE_15 {
                0: ArmStoreMemory::stfs_pw({{ Mem.sf = Fd.sf;
                                              Rn = Rn + disp8; }},
                    {{ EA = Rn + disp8; }});
                1: ArmMacroFPAOp::stfd_pw({{ }});
            }
            0x13,0x1b: decode OPCODE_15 {
                0: ArmLoadMemory::ldfs_pw({{ Fd.sf = Mem.sf;
                                             Rn = Rn + disp8; }},
                    {{ EA = Rn + disp8; }});
                1: ArmMacroFPAOp::ldfd_pw({{ }});
            }
            0x14,0x1c: decode OPCODE_15 {
                0: ArmMacroFPAOp::stfe_pn({{ }});
            }
            0x15,0x1d: decode OPCODE_15 {
                0: ArmMacroFPAOp::ldfe_pn({{ }});
            }
            0x16,0x1e: decode OPCODE_15 {
                0: ArmMacroFPAOp::stfe_pnw({{ }});
            }
            0x17,0x1f: decode OPCODE_15 {
                0: ArmMacroFPAOp::ldfe_pnw({{ }});
            }
        }
        0x2: decode PUNWL {
            // could really just decode as a single instruction
            0x00,0x04,0x08,0x0c: ArmMacroFMOp::sfm_({{ }});
            0x01,0x05,0x09,0x0d: ArmMacroFMOp::lfm_({{ }});
            0x02,0x06,0x0a,0x0e: ArmMacroFMOp::sfm_w({{ }});
            0x03,0x07,0x0b,0x0f: ArmMacroFMOp::lfm_w({{ }});
            0x10,0x14,0x18,0x1c: ArmMacroFMOp::sfm_p({{ }});
            0x11,0x15,0x19,0x1d: ArmMacroFMOp::lfm_p({{ }});
            0x12,0x16,0x1a,0x1e: ArmMacroFMOp::sfm_pw({{ }});
            0x13,0x17,0x1b,0x1f: ArmMacroFMOp::lfm_pw({{ }});
        }
        0xb: decode LOADOP {
            0x0: WarnUnimpl::fstmx();
            0x1: WarnUnimpl::fldmx();
        }
    }
    0x7: decode OPCODE_24 {
        0: decode OPCODE_4 {
            0: decode CPNUM {
                format FloatOp {
                    0x1: decode OPCODE_23_20 {
                            0x0: decode OPCODE_15 {
                                0: adf({{ Fd.sf = Fn.sf + Fm.sf; }});
                                1: mvf({{ Fd.sf = Fm.sf; }});
                            }
                            0x1: decode OPCODE_15 {
                                0: muf({{ Fd.sf = Fn.sf * Fm.sf; }});
                                1: mnf({{ Fd.sf = -Fm.sf; }});
                            }
                            0x2: decode OPCODE_15 {
                                0: suf({{ Fd.sf = Fn.sf - Fm.sf; }});
                                1: abs({{ Fd.sf = fabs(Fm.sf); }});
                            }
                            0x3: decode OPCODE_15 {
                                0: rsf({{ Fd.sf = Fm.sf - Fn.sf; }});
                                1: rnd({{ Fd.sf = rint(Fm.sf); }});
                            }
                            0x4: decode OPCODE_15 {
                                0: dvf({{ Fd.sf = Fn.sf / Fm.sf; }});
                                1: sqt({{ Fd.sf = sqrt(Fm.sf); }});
                            }
                            0x5: decode OPCODE_15 {
                                0: rdf({{ Fd.sf = Fm.sf / Fn.sf; }});
                                1: log({{ Fd.sf = log10(Fm.sf); }});
                            }
                            0x6: decode OPCODE_15 {
                                0: pow({{ Fd.sf = pow(Fm.sf, Fn.sf); }});
                                1: lgn({{ Fd.sf = log(Fm.sf); }});
                            }
                            0x7: decode OPCODE_15 {
                                0: rpw({{ Fd.sf = pow(Fn.sf, Fm.sf); }});
                                1: exp({{ Fd.sf = exp(Fm.sf); }});
                            }
                            0x8: decode OPCODE_15 {
                                0: rmf({{ Fd.sf = drem(Fn.sf, Fm.sf); }});
                                1: sin({{ Fd.sf = sin(Fm.sf); }});
                            }
                            0x9: decode OPCODE_15 {
                                0: fml({{ Fd.sf = Fn.sf * Fm.sf; }});
                                1: cos({{ Fd.sf = cos(Fm.sf); }});
                            }
                            0xa: decode OPCODE_15 {
                                0: fdv({{ Fd.sf = Fn.sf / Fm.sf; }});
                                1: tan({{ Fd.sf = tan(Fm.sf); }});
                            }
                            0xb: decode OPCODE_15 {
                                0: frd({{ Fd.sf = Fm.sf / Fn.sf; }});
                                1: asn({{ Fd.sf = asin(Fm.sf); }});
                            }
                            0xc: decode OPCODE_15 {
                                0: pol({{ Fd.sf = atan2(Fn.sf, Fm.sf); }});
                                1: acs({{ Fd.sf = acos(Fm.sf); }});
                            }
                            0xd: decode OPCODE_15 {
                                1: atn({{ Fd.sf = atan(Fm.sf); }});
                            }
                            0xe: decode OPCODE_15 {
                                // Unnormalised Round
                                1: FailUnimpl::urd();
                            }
                            0xf: decode OPCODE_15 {
                                // Normalise
                                1: FailUnimpl::nrm();
                            }
                    } // OPCODE_23_20
                } // format FloatOp
            } // CPNUM
            1: decode CPNUM { // 27-24=1110,4 ==1
                1: decode OPCODE_15_12 {
                    format FloatOp {
                        0xf: decode OPCODE_23_21 {
                            format FloatCmp {
                                0x4: cmf({{ Fn.df }}, {{ Fm.df }});
                                0x5: cnf({{ Fn.df }}, {{ -Fm.df }});
                                0x6: cmfe({{ Fn.df }}, {{ Fm.df}});
                                0x7: cnfe({{ Fn.df }}, {{ -Fm.df}});
                            }
                        }
                        default: decode OPCODE_23_20 {
                            0x0: decode OPCODE_7 {
                                0: flts({{ Fn.sf = (float) Rd.sw; }});
                                1: fltd({{ Fn.df = (double) Rd.sw; }});
                            }
                            0x1: decode OPCODE_7 {
                                0: fixs({{ Rd = (uint32_t) Fm.sf; }});
                                1: fixd({{ Rd = (uint32_t) Fm.df; }});
                            }
                            0x2: wfs({{ Fpsr = Rd; }});
                            0x3: rfs({{ Rd = Fpsr; }});
                            0x4: FailUnimpl::wfc();
                            0x5: FailUnimpl::rfc();
                        }
                    } // format FloatOp
                }
                0xa: decode MISC_OPCODE {
                    0x1: decode MEDIA_OPCODE {
                        0xf: decode RN {
                            0x0: FloatOp::fmrx_fpsid({{ Rd = Fpsid; }});
                            0x1: FloatOp::fmrx_fpscr({{ Rd = Fpscr; }});
                            0x8: FloatOp::fmrx_fpexc({{ Rd = Fpexc; }});
                        }
                        0xe: decode RN {
                            0x0: FloatOp::fmxr_fpsid({{ Fpsid = Rd; }});
                            0x1: FloatOp::fmxr_fpscr({{ Fpscr = Rd; }});
                            0x8: FloatOp::fmxr_fpexc({{ Fpexc = Rd; }});
                        }
                    } // MEDIA_OPCODE (MISC_OPCODE 0x1)
                } // MISC_OPCODE (CPNUM 0xA)
                0xf: decode RN {
                    // Barrriers, Cache Maintence, NOPS
                    7: decode OPCODE_23_21 {
                        0: decode RM {
                            0: decode OPC2 {
                                4: decode OPCODE_20 {
                                    0: PredOp::mcr_cp15_nop1({{ }}); // was wfi
                                }
                            }
                            1: WarnUnimpl::cp15_cache_maint();
                            4: WarnUnimpl::cp15_par();
                            5: decode OPC2 {
                                0,1: WarnUnimpl::cp15_cache_maint2();
                                4: PredOp::cp15_isb({{ ; }}, IsMemBarrier, IsSerializeBefore);
                                6,7: WarnUnimpl::cp15_bp_maint();
                            }
                            6: WarnUnimpl::cp15_cache_maint3();
                            8: WarnUnimpl::cp15_va_to_pa();
                            10: decode OPC2 {
                                1,2: WarnUnimpl::cp15_cache_maint3();
                                4: PredOp::cp15_dsb({{ ; }}, IsMemBarrier, IsSerializeBefore);
                                5: PredOp::cp15_dmb({{ ; }}, IsMemBarrier, IsSerializeBefore);
                            }
                            11: WarnUnimpl::cp15_cache_maint4();
                            13: decode OPC2 {
                                1: decode OPCODE_20 {
                                    0: PredOp::mcr_cp15_nop2({{ }}); // was prefetch
                                }
                            }
                            14: WarnUnimpl::cp15_cache_maint5();
                        } // RM
                    } // OPCODE_23_21 CR

                    // Thread ID and context ID registers
                    // Thread ID register needs cheaper access than miscreg
                    13: WarnUnimpl::mcr_mrc_cp15_c7();

                    // All the rest
                    default: decode OPCODE_20 {
                        0: PredOp::mcr_cp15({{
                               fault = setCp15Register(Rd, RN, OPCODE_23_21, RM, OPC2);
                        }});
                        1: PredOp::mrc_cp15({{
                               fault = readCp15Register(Rd, RN, OPCODE_23_21, RM, OPC2);
                        }});
                    }
                }  // RN
            } // CPNUM  (OP4 == 1)
        } //OPCODE_4

#if FULL_SYSTEM
        1: PredOp::swi({{ fault = new SupervisorCall; }}, IsSerializeAfter, IsNonSpeculative, IsSyscall);
#else
        1: PredOp::swi({{ if (testPredicate(CondCodes, condCode))
            {
                if (IMMED_23_0)
                    xc->syscall(IMMED_23_0);
                else
                    xc->syscall(R7);
            }
        }});
#endif // FULL_SYSTEM
    } // OPCODE_24

}
}