disas/libvixl/vixl/a64/decoder-a64.cc

   1 // Copyright 2014, ARM Limited
   2 // All rights reserved.
   3 //
   4 // Redistribution and use in source and binary forms, with or without
   5 // modification, are permitted provided that the following conditions are met:
   6 //
   7 //   * Redistributions of source code must retain the above copyright notice,
   8 //     this list of conditions and the following disclaimer.
   9 //   * Redistributions in binary form must reproduce the above copyright notice,
  10 //     this list of conditions and the following disclaimer in the documentation
  11 //     and/or other materials provided with the distribution.
  12 //   * Neither the name of ARM Limited nor the names of its contributors may be
  13 //     used to endorse or promote products derived from this software without
  14 //     specific prior written permission.
  15 //
  16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS CONTRIBUTORS "AS IS" AND
  17 // ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  18 // WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  19 // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
  20 // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21 // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  22 // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  23 // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  24 // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  25 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26
  27 #include "vixl/globals.h"
  28 #include "vixl/utils.h"
  29 #include "vixl/a64/decoder-a64.h"
  30
  31 namespace vixl {
  32
  33 void Decoder::DecodeInstruction(const Instruction *instr) {
  34   if (instr->Bits(28, 27) == 0) {
  35     VisitUnallocated(instr);
  36   } else {
  37     switch (instr->Bits(27, 24)) {
  38       // 0:   PC relative addressing.
  39       case 0x0: DecodePCRelAddressing(instr); break;
  40
  41       // 1:   Add/sub immediate.
  42       case 0x1: DecodeAddSubImmediate(instr); break;
  43
  44       // A:   Logical shifted register.
  45       //      Add/sub with carry.
  46       //      Conditional compare register.
  47       //      Conditional compare immediate.
  48       //      Conditional select.
  49       //      Data processing 1 source.
  50       //      Data processing 2 source.
  51       // B:   Add/sub shifted register.
  52       //      Add/sub extended register.
  53       //      Data processing 3 source.
  54       case 0xA:
  55       case 0xB: DecodeDataProcessing(instr); break;
  56
  57       // 2:   Logical immediate.
  58       //      Move wide immediate.
  59       case 0x2: DecodeLogical(instr); break;
  60
  61       // 3:   Bitfield.
  62       //      Extract.
  63       case 0x3: DecodeBitfieldExtract(instr); break;
  64
  65       // 4:   Unconditional branch immediate.
  66       //      Exception generation.
  67       //      Compare and branch immediate.
  68       // 5:   Compare and branch immediate.
  69       //      Conditional branch.
  70       //      System.
  71       // 6,7: Unconditional branch.
  72       //      Test and branch immediate.
  73       case 0x4:
  74       case 0x5:
  75       case 0x6:
  76       case 0x7: DecodeBranchSystemException(instr); break;
  77
  78       // 8,9: Load/store register pair post-index.
  79       //      Load register literal.
  80       //      Load/store register unscaled immediate.
  81       //      Load/store register immediate post-index.
  82       //      Load/store register immediate pre-index.
  83       //      Load/store register offset.
  84       //      Load/store exclusive.
  85       // C,D: Load/store register pair offset.
  86       //      Load/store register pair pre-index.
  87       //      Load/store register unsigned immediate.
  88       //      Advanced SIMD.
  89       case 0x8:
  90       case 0x9:
  91       case 0xC:
  92       case 0xD: DecodeLoadStore(instr); break;
  93
  94       // E:   FP fixed point conversion.
  95       //      FP integer conversion.
  96       //      FP data processing 1 source.
  97       //      FP compare.
  98       //      FP immediate.
  99       //      FP data processing 2 source.
 100       //      FP conditional compare.
 101       //      FP conditional select.
 102       //      Advanced SIMD.
 103       // F:   FP data processing 3 source.
 104       //      Advanced SIMD.
 105       case 0xE:
 106       case 0xF: DecodeFP(instr); break;
 107     }
 108   }
 109 }
 110
 111 void Decoder::AppendVisitor(DecoderVisitor* new_visitor) {
 112   visitors_.push_back(new_visitor);
 113 }
 114
 115
 116 void Decoder::PrependVisitor(DecoderVisitor* new_visitor) {
 117   visitors_.push_front(new_visitor);
 118 }
 119
 120
 121 void Decoder::InsertVisitorBefore(DecoderVisitor* new_visitor,
 122                                   DecoderVisitor* registered_visitor) {
 123   std::list<DecoderVisitor*>::iterator it;
 124   for (it = visitors_.begin(); it != visitors_.end(); it++) {
 125     if (*it == registered_visitor) {
 126       visitors_.insert(it, new_visitor);
 127       return;
 128     }
 129   }
 130   // We reached the end of the list. The last element must be
 131   // registered_visitor.
 132   VIXL_ASSERT(*it == registered_visitor);
 133   visitors_.insert(it, new_visitor);
 134 }
 135
 136
 137 void Decoder::InsertVisitorAfter(DecoderVisitor* new_visitor,
 138                                  DecoderVisitor* registered_visitor) {
 139   std::list<DecoderVisitor*>::iterator it;
 140   for (it = visitors_.begin(); it != visitors_.end(); it++) {
 141     if (*it == registered_visitor) {
 142       it++;
 143       visitors_.insert(it, new_visitor);
 144       return;
 145     }
 146   }
 147   // We reached the end of the list. The last element must be
 148   // registered_visitor.
 149   VIXL_ASSERT(*it == registered_visitor);
 150   visitors_.push_back(new_visitor);
 151 }
 152
 153
 154 void Decoder::RemoveVisitor(DecoderVisitor* visitor) {
 155   visitors_.remove(visitor);
 156 }
 157
 158
 159 void Decoder::DecodePCRelAddressing(const Instruction* instr) {
 160   VIXL_ASSERT(instr->Bits(27, 24) == 0x0);
 161   // We know bit 28 is set, as <b28:b27> = 0 is filtered out at the top level
 162   // decode.
 163   VIXL_ASSERT(instr->Bit(28) == 0x1);
 164   VisitPCRelAddressing(instr);
 165 }
 166
 167
 168 void Decoder::DecodeBranchSystemException(const Instruction* instr) {
 169   VIXL_ASSERT((instr->Bits(27, 24) == 0x4) ||
 170               (instr->Bits(27, 24) == 0x5) ||
 171               (instr->Bits(27, 24) == 0x6) ||
 172               (instr->Bits(27, 24) == 0x7) );
 173
 174   switch (instr->Bits(31, 29)) {
 175     case 0:
 176     case 4: {
 177       VisitUnconditionalBranch(instr);
 178       break;
 179     }
 180     case 1:
 181     case 5: {
 182       if (instr->Bit(25) == 0) {
 183         VisitCompareBranch(instr);
 184       } else {
 185         VisitTestBranch(instr);
 186       }
 187       break;
 188     }
 189     case 2: {
 190       if (instr->Bit(25) == 0) {
 191         if ((instr->Bit(24) == 0x1) ||
 192             (instr->Mask(0x01000010) == 0x00000010)) {
 193           VisitUnallocated(instr);
 194         } else {
 195           VisitConditionalBranch(instr);
 196         }
 197       } else {
 198         VisitUnallocated(instr);
 199       }
 200       break;
 201     }
 202     case 6: {
 203       if (instr->Bit(25) == 0) {
 204         if (instr->Bit(24) == 0) {
 205           if ((instr->Bits(4, 2) != 0) ||
 206               (instr->Mask(0x00E0001D) == 0x00200001) ||
 207               (instr->Mask(0x00E0001D) == 0x00400001) ||
 208               (instr->Mask(0x00E0001E) == 0x00200002) ||
 209               (instr->Mask(0x00E0001E) == 0x00400002) ||
 210               (instr->Mask(0x00E0001C) == 0x00600000) ||
 211               (instr->Mask(0x00E0001C) == 0x00800000) ||
 212               (instr->Mask(0x00E0001F) == 0x00A00000) ||
 213               (instr->Mask(0x00C0001C) == 0x00C00000)) {
 214             VisitUnallocated(instr);
 215           } else {
 216             VisitException(instr);
 217           }
 218         } else {
 219           if (instr->Bits(23, 22) == 0) {
 220             const Instr masked_003FF0E0 = instr->Mask(0x003FF0E0);
 221             if ((instr->Bits(21, 19) == 0x4) ||
 222                 (masked_003FF0E0 == 0x00033000) ||
 223                 (masked_003FF0E0 == 0x003FF020) ||
 224                 (masked_003FF0E0 == 0x003FF060) ||
 225                 (masked_003FF0E0 == 0x003FF0E0) ||
 226                 (instr->Mask(0x00388000) == 0x00008000) ||
 227                 (instr->Mask(0x0038E000) == 0x00000000) ||
 228                 (instr->Mask(0x0039E000) == 0x00002000) ||
 229                 (instr->Mask(0x003AE000) == 0x00002000) ||
 230                 (instr->Mask(0x003CE000) == 0x00042000) ||
 231                 (instr->Mask(0x003FFFC0) == 0x000320C0) ||
 232                 (instr->Mask(0x003FF100) == 0x00032100) ||
 233                 (instr->Mask(0x003FF200) == 0x00032200) ||
 234                 (instr->Mask(0x003FF400) == 0x00032400) ||
 235                 (instr->Mask(0x003FF800) == 0x00032800) ||
 236                 (instr->Mask(0x0038F000) == 0x00005000) ||
 237                 (instr->Mask(0x0038E000) == 0x00006000)) {
 238               VisitUnallocated(instr);
 239             } else {
 240               VisitSystem(instr);
 241             }
 242           } else {
 243             VisitUnallocated(instr);
 244           }
 245         }
 246       } else {
 247         if ((instr->Bit(24) == 0x1) ||
 248             (instr->Bits(20, 16) != 0x1F) ||
 249             (instr->Bits(15, 10) != 0) ||
 250             (instr->Bits(4, 0) != 0) ||
 251             (instr->Bits(24, 21) == 0x3) ||
 252             (instr->Bits(24, 22) == 0x3)) {
 253           VisitUnallocated(instr);
 254         } else {
 255           VisitUnconditionalBranchToRegister(instr);
 256         }
 257       }
 258       break;
 259     }
 260     case 3:
 261     case 7: {
 262       VisitUnallocated(instr);
 263       break;
 264     }
 265   }
 266 }
 267
 268
 269 void Decoder::DecodeLoadStore(const Instruction* instr) {
 270   VIXL_ASSERT((instr->Bits(27, 24) == 0x8) ||
 271               (instr->Bits(27, 24) == 0x9) ||
 272               (instr->Bits(27, 24) == 0xC) ||
 273               (instr->Bits(27, 24) == 0xD) );
 274   // TODO(all): rearrange the tree to integrate this branch.
 275   if ((instr->Bit(28) == 0) && (instr->Bit(29) == 0) && (instr->Bit(26) == 1)) {
 276     DecodeNEONLoadStore(instr);
 277     return;
 278   }
 279
 280   if (instr->Bit(24) == 0) {
 281     if (instr->Bit(28) == 0) {
 282       if (instr->Bit(29) == 0) {
 283         if (instr->Bit(26) == 0) {
 284           VisitLoadStoreExclusive(instr);
 285         } else {
 286           VIXL_UNREACHABLE();
 287         }
 288       } else {
 289         if ((instr->Bits(31, 30) == 0x3) ||
 290             (instr->Mask(0xC4400000) == 0x40000000)) {
 291           VisitUnallocated(instr);
 292         } else {
 293           if (instr->Bit(23) == 0) {
 294             if (instr->Mask(0xC4400000) == 0xC0400000) {
 295               VisitUnallocated(instr);
 296             } else {
 297               VisitLoadStorePairNonTemporal(instr);
 298             }
 299           } else {
 300             VisitLoadStorePairPostIndex(instr);
 301           }
 302         }
 303       }
 304     } else {
 305       if (instr->Bit(29) == 0) {
 306         if (instr->Mask(0xC4000000) == 0xC4000000) {
 307           VisitUnallocated(instr);
 308         } else {
 309           VisitLoadLiteral(instr);
 310         }
 311       } else {
 312         if ((instr->Mask(0x84C00000) == 0x80C00000) ||
 313             (instr->Mask(0x44800000) == 0x44800000) ||
 314             (instr->Mask(0x84800000) == 0x84800000)) {
 315           VisitUnallocated(instr);
 316         } else {
 317           if (instr->Bit(21) == 0) {
 318             switch (instr->Bits(11, 10)) {
 319               case 0: {
 320                 VisitLoadStoreUnscaledOffset(instr);
 321                 break;
 322               }
 323               case 1: {
 324                 if (instr->Mask(0xC4C00000) == 0xC0800000) {
 325                   VisitUnallocated(instr);
 326                 } else {
 327                   VisitLoadStorePostIndex(instr);
 328                 }
 329                 break;
 330               }
 331               case 2: {
 332                 // TODO: VisitLoadStoreRegisterOffsetUnpriv.
 333                 VisitUnimplemented(instr);
 334                 break;
 335               }
 336               case 3: {
 337                 if (instr->Mask(0xC4C00000) == 0xC0800000) {
 338                   VisitUnallocated(instr);
 339                 } else {
 340                   VisitLoadStorePreIndex(instr);
 341                 }
 342                 break;
 343               }
 344             }
 345           } else {
 346             if (instr->Bits(11, 10) == 0x2) {
 347               if (instr->Bit(14) == 0) {
 348                 VisitUnallocated(instr);
 349               } else {
 350                 VisitLoadStoreRegisterOffset(instr);
 351               }
 352             } else {
 353               VisitUnallocated(instr);
 354             }
 355           }
 356         }
 357       }
 358     }
 359   } else {
 360     if (instr->Bit(28) == 0) {
 361       if (instr->Bit(29) == 0) {
 362         VisitUnallocated(instr);
 363       } else {
 364         if ((instr->Bits(31, 30) == 0x3) ||
 365             (instr->Mask(0xC4400000) == 0x40000000)) {
 366           VisitUnallocated(instr);
 367         } else {
 368           if (instr->Bit(23) == 0) {
 369             VisitLoadStorePairOffset(instr);
 370           } else {
 371             VisitLoadStorePairPreIndex(instr);
 372           }
 373         }
 374       }
 375     } else {
 376       if (instr->Bit(29) == 0) {
 377         VisitUnallocated(instr);
 378       } else {
 379         if ((instr->Mask(0x84C00000) == 0x80C00000) ||
 380             (instr->Mask(0x44800000) == 0x44800000) ||
 381             (instr->Mask(0x84800000) == 0x84800000)) {
 382           VisitUnallocated(instr);
 383         } else {
 384           VisitLoadStoreUnsignedOffset(instr);
 385         }
 386       }
 387     }
 388   }
 389 }
 390
 391
 392 void Decoder::DecodeLogical(const Instruction* instr) {
 393   VIXL_ASSERT(instr->Bits(27, 24) == 0x2);
 394
 395   if (instr->Mask(0x80400000) == 0x00400000) {
 396     VisitUnallocated(instr);
 397   } else {
 398     if (instr->Bit(23) == 0) {
 399       VisitLogicalImmediate(instr);
 400     } else {
 401       if (instr->Bits(30, 29) == 0x1) {
 402         VisitUnallocated(instr);
 403       } else {
 404         VisitMoveWideImmediate(instr);
 405       }
 406     }
 407   }
 408 }
 409
 410
 411 void Decoder::DecodeBitfieldExtract(const Instruction* instr) {
 412   VIXL_ASSERT(instr->Bits(27, 24) == 0x3);
 413
 414   if ((instr->Mask(0x80400000) == 0x80000000) ||
 415       (instr->Mask(0x80400000) == 0x00400000) ||
 416       (instr->Mask(0x80008000) == 0x00008000)) {
 417     VisitUnallocated(instr);
 418   } else if (instr->Bit(23) == 0) {
 419     if ((instr->Mask(0x80200000) == 0x00200000) ||
 420         (instr->Mask(0x60000000) == 0x60000000)) {
 421       VisitUnallocated(instr);
 422     } else {
 423       VisitBitfield(instr);
 424     }
 425   } else {
 426     if ((instr->Mask(0x60200000) == 0x00200000) ||
 427         (instr->Mask(0x60000000) != 0x00000000)) {
 428       VisitUnallocated(instr);
 429     } else {
 430       VisitExtract(instr);
 431     }
 432   }
 433 }
 434
 435
 436 void Decoder::DecodeAddSubImmediate(const Instruction* instr) {
 437   VIXL_ASSERT(instr->Bits(27, 24) == 0x1);
 438   if (instr->Bit(23) == 1) {
 439     VisitUnallocated(instr);
 440   } else {
 441     VisitAddSubImmediate(instr);
 442   }
 443 }
 444
 445
 446 void Decoder::DecodeDataProcessing(const Instruction* instr) {
 447   VIXL_ASSERT((instr->Bits(27, 24) == 0xA) ||
 448               (instr->Bits(27, 24) == 0xB));
 449
 450   if (instr->Bit(24) == 0) {
 451     if (instr->Bit(28) == 0) {
 452       if (instr->Mask(0x80008000) == 0x00008000) {
 453         VisitUnallocated(instr);
 454       } else {
 455         VisitLogicalShifted(instr);
 456       }
 457     } else {
 458       switch (instr->Bits(23, 21)) {
 459         case 0: {
 460           if (instr->Mask(0x0000FC00) != 0) {
 461             VisitUnallocated(instr);
 462           } else {
 463             VisitAddSubWithCarry(instr);
 464           }
 465           break;
 466         }
 467         case 2: {
 468           if ((instr->Bit(29) == 0) ||
 469               (instr->Mask(0x00000410) != 0)) {
 470             VisitUnallocated(instr);
 471           } else {
 472             if (instr->Bit(11) == 0) {
 473               VisitConditionalCompareRegister(instr);
 474             } else {
 475               VisitConditionalCompareImmediate(instr);
 476             }
 477           }
 478           break;
 479         }
 480         case 4: {
 481           if (instr->Mask(0x20000800) != 0x00000000) {
 482             VisitUnallocated(instr);
 483           } else {
 484             VisitConditionalSelect(instr);
 485           }
 486           break;
 487         }
 488         case 6: {
 489           if (instr->Bit(29) == 0x1) {
 490             VisitUnallocated(instr);
 491             VIXL_FALLTHROUGH();
 492           } else {
 493             if (instr->Bit(30) == 0) {
 494               if ((instr->Bit(15) == 0x1) ||
 495                   (instr->Bits(15, 11) == 0) ||
 496                   (instr->Bits(15, 12) == 0x1) ||
 497                   (instr->Bits(15, 12) == 0x3) ||
 498                   (instr->Bits(15, 13) == 0x3) ||
 499                   (instr->Mask(0x8000EC00) == 0x00004C00) ||
 500                   (instr->Mask(0x8000E800) == 0x80004000) ||
 501                   (instr->Mask(0x8000E400) == 0x80004000)) {
 502                 VisitUnallocated(instr);
 503               } else {
 504                 VisitDataProcessing2Source(instr);
 505               }
 506             } else {
 507               if ((instr->Bit(13) == 1) ||
 508                   (instr->Bits(20, 16) != 0) ||
 509                   (instr->Bits(15, 14) != 0) ||
 510                   (instr->Mask(0xA01FFC00) == 0x00000C00) ||
 511                   (instr->Mask(0x201FF800) == 0x00001800)) {
 512                 VisitUnallocated(instr);
 513               } else {
 514                 VisitDataProcessing1Source(instr);
 515               }
 516             }
 517             break;
 518           }
 519         }
 520         case 1:
 521         case 3:
 522         case 5:
 523         case 7: VisitUnallocated(instr); break;
 524       }
 525     }
 526   } else {
 527     if (instr->Bit(28) == 0) {
 528      if (instr->Bit(21) == 0) {
 529         if ((instr->Bits(23, 22) == 0x3) ||
 530             (instr->Mask(0x80008000) == 0x00008000)) {
 531           VisitUnallocated(instr);
 532         } else {
 533           VisitAddSubShifted(instr);
 534         }
 535       } else {
 536         if ((instr->Mask(0x00C00000) != 0x00000000) ||
 537             (instr->Mask(0x00001400) == 0x00001400) ||
 538             (instr->Mask(0x00001800) == 0x00001800)) {
 539           VisitUnallocated(instr);
 540         } else {
 541           VisitAddSubExtended(instr);
 542         }
 543       }
 544     } else {
 545       if ((instr->Bit(30) == 0x1) ||
 546           (instr->Bits(30, 29) == 0x1) ||
 547           (instr->Mask(0xE0600000) == 0x00200000) ||
 548           (instr->Mask(0xE0608000) == 0x00400000) ||
 549           (instr->Mask(0x60608000) == 0x00408000) ||
 550           (instr->Mask(0x60E00000) == 0x00E00000) ||
 551           (instr->Mask(0x60E00000) == 0x00800000) ||
 552           (instr->Mask(0x60E00000) == 0x00600000)) {
 553         VisitUnallocated(instr);
 554       } else {
 555         VisitDataProcessing3Source(instr);
 556       }
 557     }
 558   }
 559 }
 560
 561
 562 void Decoder::DecodeFP(const Instruction* instr) {
 563   VIXL_ASSERT((instr->Bits(27, 24) == 0xE) ||
 564               (instr->Bits(27, 24) == 0xF));
 565   if (instr->Bit(28) == 0) {
 566     DecodeNEONVectorDataProcessing(instr);
 567   } else {
 568     if (instr->Bits(31, 30) == 0x3) {
 569       VisitUnallocated(instr);
 570     } else if (instr->Bits(31, 30) == 0x1) {
 571       DecodeNEONScalarDataProcessing(instr);
 572     } else {
 573       if (instr->Bit(29) == 0) {
 574         if (instr->Bit(24) == 0) {
 575           if (instr->Bit(21) == 0) {
 576             if ((instr->Bit(23) == 1) ||
 577                 (instr->Bit(18) == 1) ||
 578                 (instr->Mask(0x80008000) == 0x00000000) ||
 579                 (instr->Mask(0x000E0000) == 0x00000000) ||
 580                 (instr->Mask(0x000E0000) == 0x000A0000) ||
 581                 (instr->Mask(0x00160000) == 0x00000000) ||
 582                 (instr->Mask(0x00160000) == 0x00120000)) {
 583               VisitUnallocated(instr);
 584             } else {
 585               VisitFPFixedPointConvert(instr);
 586             }
 587           } else {
 588             if (instr->Bits(15, 10) == 32) {
 589               VisitUnallocated(instr);
 590             } else if (instr->Bits(15, 10) == 0) {
 591               if ((instr->Bits(23, 22) == 0x3) ||
 592                   (instr->Mask(0x000E0000) == 0x000A0000) ||
 593                   (instr->Mask(0x000E0000) == 0x000C0000) ||
 594                   (instr->Mask(0x00160000) == 0x00120000) ||
 595                   (instr->Mask(0x00160000) == 0x00140000) ||
 596                   (instr->Mask(0x20C40000) == 0x00800000) ||
 597                   (instr->Mask(0x20C60000) == 0x00840000) ||
 598                   (instr->Mask(0xA0C60000) == 0x80060000) ||
 599                   (instr->Mask(0xA0C60000) == 0x00860000) ||
 600                   (instr->Mask(0xA0C60000) == 0x00460000) ||
 601                   (instr->Mask(0xA0CE0000) == 0x80860000) ||
 602                   (instr->Mask(0xA0CE0000) == 0x804E0000) ||
 603                   (instr->Mask(0xA0CE0000) == 0x000E0000) ||
 604                   (instr->Mask(0xA0D60000) == 0x00160000) ||
 605                   (instr->Mask(0xA0D60000) == 0x80560000) ||
 606                   (instr->Mask(0xA0D60000) == 0x80960000)) {
 607                 VisitUnallocated(instr);
 608               } else {
 609                 VisitFPIntegerConvert(instr);
 610               }
 611             } else if (instr->Bits(14, 10) == 16) {
 612               const Instr masked_A0DF8000 = instr->Mask(0xA0DF8000);
 613               if ((instr->Mask(0x80180000) != 0) ||
 614                   (masked_A0DF8000 == 0x00020000) ||
 615                   (masked_A0DF8000 == 0x00030000) ||
 616                   (masked_A0DF8000 == 0x00068000) ||
 617                   (masked_A0DF8000 == 0x00428000) ||
 618                   (masked_A0DF8000 == 0x00430000) ||
 619                   (masked_A0DF8000 == 0x00468000) ||
 620                   (instr->Mask(0xA0D80000) == 0x00800000) ||
 621                   (instr->Mask(0xA0DE0000) == 0x00C00000) ||
 622                   (instr->Mask(0xA0DF0000) == 0x00C30000) ||
 623                   (instr->Mask(0xA0DC0000) == 0x00C40000)) {
 624                 VisitUnallocated(instr);
 625               } else {
 626                 VisitFPDataProcessing1Source(instr);
 627               }
 628             } else if (instr->Bits(13, 10) == 8) {
 629               if ((instr->Bits(15, 14) != 0) ||
 630                   (instr->Bits(2, 0) != 0) ||
 631                   (instr->Mask(0x80800000) != 0x00000000)) {
 632                 VisitUnallocated(instr);
 633               } else {
 634                 VisitFPCompare(instr);
 635               }
 636             } else if (instr->Bits(12, 10) == 4) {
 637               if ((instr->Bits(9, 5) != 0) ||
 638                   (instr->Mask(0x80800000) != 0x00000000)) {
 639                 VisitUnallocated(instr);
 640               } else {
 641                 VisitFPImmediate(instr);
 642               }
 643             } else {
 644               if (instr->Mask(0x80800000) != 0x00000000) {
 645                 VisitUnallocated(instr);
 646               } else {
 647                 switch (instr->Bits(11, 10)) {
 648                   case 1: {
 649                     VisitFPConditionalCompare(instr);
 650                     break;
 651                   }
 652                   case 2: {
 653                     if ((instr->Bits(15, 14) == 0x3) ||
 654                         (instr->Mask(0x00009000) == 0x00009000) ||
 655                         (instr->Mask(0x0000A000) == 0x0000A000)) {
 656                       VisitUnallocated(instr);
 657                     } else {
 658                       VisitFPDataProcessing2Source(instr);
 659                     }
 660                     break;
 661                   }
 662                   case 3: {
 663                     VisitFPConditionalSelect(instr);
 664                     break;
 665                   }
 666                   default: VIXL_UNREACHABLE();
 667                 }
 668               }
 669             }
 670           }
 671         } else {
 672           // Bit 30 == 1 has been handled earlier.
 673           VIXL_ASSERT(instr->Bit(30) == 0);
 674           if (instr->Mask(0xA0800000) != 0) {
 675             VisitUnallocated(instr);
 676           } else {
 677             VisitFPDataProcessing3Source(instr);
 678           }
 679         }
 680       } else {
 681         VisitUnallocated(instr);
 682       }
 683     }
 684   }
 685 }
 686
 687
 688 void Decoder::DecodeNEONLoadStore(const Instruction* instr) {
 689   VIXL_ASSERT(instr->Bits(29, 25) == 0x6);
 690   if (instr->Bit(31) == 0) {
 691     if ((instr->Bit(24) == 0) && (instr->Bit(21) == 1)) {
 692       VisitUnallocated(instr);
 693       return;
 694     }
 695
 696     if (instr->Bit(23) == 0) {
 697       if (instr->Bits(20, 16) == 0) {
 698         if (instr->Bit(24) == 0) {
 699           VisitNEONLoadStoreMultiStruct(instr);
 700         } else {
 701           VisitNEONLoadStoreSingleStruct(instr);
 702         }
 703       } else {
 704         VisitUnallocated(instr);
 705       }
 706     } else {
 707       if (instr->Bit(24) == 0) {
 708         VisitNEONLoadStoreMultiStructPostIndex(instr);
 709       } else {
 710         VisitNEONLoadStoreSingleStructPostIndex(instr);
 711       }
 712     }
 713   } else {
 714     VisitUnallocated(instr);
 715   }
 716 }
 717
 718
 719 void Decoder::DecodeNEONVectorDataProcessing(const Instruction* instr) {
 720   VIXL_ASSERT(instr->Bits(28, 25) == 0x7);
 721   if (instr->Bit(31) == 0) {
 722     if (instr->Bit(24) == 0) {
 723       if (instr->Bit(21) == 0) {
 724         if (instr->Bit(15) == 0) {
 725           if (instr->Bit(10) == 0) {
 726             if (instr->Bit(29) == 0) {
 727               if (instr->Bit(11) == 0) {
 728                 VisitNEONTable(instr);
 729               } else {
 730                 VisitNEONPerm(instr);
 731               }
 732             } else {
 733               VisitNEONExtract(instr);
 734             }
 735           } else {
 736             if (instr->Bits(23, 22) == 0) {
 737               VisitNEONCopy(instr);
 738             } else {
 739               VisitUnallocated(instr);
 740             }
 741           }
 742         } else {
 743           VisitUnallocated(instr);
 744         }
 745       } else {
 746         if (instr->Bit(10) == 0) {
 747           if (instr->Bit(11) == 0) {
 748             VisitNEON3Different(instr);
 749           } else {
 750             if (instr->Bits(18, 17) == 0) {
 751               if (instr->Bit(20) == 0) {
 752                 if (instr->Bit(19) == 0) {
 753                   VisitNEON2RegMisc(instr);
 754                 } else {
 755                   if (instr->Bits(30, 29) == 0x2) {
 756                     VisitCryptoAES(instr);
 757                   } else {
 758                     VisitUnallocated(instr);
 759                   }
 760                 }
 761               } else {
 762                 if (instr->Bit(19) == 0) {
 763                   VisitNEONAcrossLanes(instr);
 764                 } else {
 765                   VisitUnallocated(instr);
 766                 }
 767               }
 768             } else {
 769               VisitUnallocated(instr);
 770             }
 771           }
 772         } else {
 773           VisitNEON3Same(instr);
 774         }
 775       }
 776     } else {
 777       if (instr->Bit(10) == 0) {
 778         VisitNEONByIndexedElement(instr);
 779       } else {
 780         if (instr->Bit(23) == 0) {
 781           if (instr->Bits(22, 19) == 0) {
 782             VisitNEONModifiedImmediate(instr);
 783           } else {
 784             VisitNEONShiftImmediate(instr);
 785           }
 786         } else {
 787           VisitUnallocated(instr);
 788         }
 789       }
 790     }
 791   } else {
 792     VisitUnallocated(instr);
 793   }
 794 }
 795
 796
 797 void Decoder::DecodeNEONScalarDataProcessing(const Instruction* instr) {
 798   VIXL_ASSERT(instr->Bits(28, 25) == 0xF);
 799   if (instr->Bit(24) == 0) {
 800     if (instr->Bit(21) == 0) {
 801       if (instr->Bit(15) == 0) {
 802         if (instr->Bit(10) == 0) {
 803           if (instr->Bit(29) == 0) {
 804             if (instr->Bit(11) == 0) {
 805               VisitCrypto3RegSHA(instr);
 806             } else {
 807               VisitUnallocated(instr);
 808             }
 809           } else {
 810             VisitUnallocated(instr);
 811           }
 812         } else {
 813           if (instr->Bits(23, 22) == 0) {
 814             VisitNEONScalarCopy(instr);
 815           } else {
 816             VisitUnallocated(instr);
 817           }
 818         }
 819       } else {
 820         VisitUnallocated(instr);
 821       }
 822     } else {
 823       if (instr->Bit(10) == 0) {
 824         if (instr->Bit(11) == 0) {
 825           VisitNEONScalar3Diff(instr);
 826         } else {
 827           if (instr->Bits(18, 17) == 0) {
 828             if (instr->Bit(20) == 0) {
 829               if (instr->Bit(19) == 0) {
 830                 VisitNEONScalar2RegMisc(instr);
 831               } else {
 832                 if (instr->Bit(29) == 0) {
 833                   VisitCrypto2RegSHA(instr);
 834                 } else {
 835                   VisitUnallocated(instr);
 836                 }
 837               }
 838             } else {
 839               if (instr->Bit(19) == 0) {
 840                 VisitNEONScalarPairwise(instr);
 841               } else {
 842                 VisitUnallocated(instr);
 843               }
 844             }
 845           } else {
 846             VisitUnallocated(instr);
 847           }
 848         }
 849       } else {
 850         VisitNEONScalar3Same(instr);
 851       }
 852     }
 853   } else {
 854     if (instr->Bit(10) == 0) {
 855       VisitNEONScalarByIndexedElement(instr);
 856     } else {
 857       if (instr->Bit(23) == 0) {
 858         VisitNEONScalarShiftImmediate(instr);
 859       } else {
 860         VisitUnallocated(instr);
 861       }
 862     }
 863   }
 864 }
 865
 866
 867 #define DEFINE_VISITOR_CALLERS(A)                                              \
 868   void Decoder::Visit##A(const Instruction *instr) {                           \
 869     VIXL_ASSERT(instr->Mask(A##FMask) == A##Fixed);                            \
 870     std::list<DecoderVisitor*>::iterator it;                                   \
 871     for (it = visitors_.begin(); it != visitors_.end(); it++) {                \
 872       (*it)->Visit##A(instr);                                                  \
 873     }                                                                          \
 874   }
 875 VISITOR_LIST(DEFINE_VISITOR_CALLERS)
 876 #undef DEFINE_VISITOR_CALLERS
 877 }  // namespace vixl