1 // Copyright 2011 the V8 project authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef V8_ARM_CONSTANTS_ARM_H_ 6 #define V8_ARM_CONSTANTS_ARM_H_ 7 8 #include <stdint.h> 9 10 #include "src/base/logging.h" 11 #include "src/base/macros.h" 12 #include "src/globals.h" 13 14 // ARM EABI is required. 15 #if defined(__arm__) && !defined(__ARM_EABI__) 16 #error ARM EABI support is required. 17 #endif 18 19 namespace v8 { 20 namespace internal { 21 22 // Constant pool marker. 23 // Use UDF, the permanently undefined instruction. 24 const int kConstantPoolMarkerMask = 0xfff000f0; 25 const int kConstantPoolMarker = 0xe7f000f0; 26 const int kConstantPoolLengthMaxMask = 0xffff; 27 inline int EncodeConstantPoolLength(int length) { 28 DCHECK((length & kConstantPoolLengthMaxMask) == length); 29 return ((length & 0xfff0) << 4) | (length & 0xf); 30 } 31 inline int DecodeConstantPoolLength(int instr) { 32 DCHECK((instr & kConstantPoolMarkerMask) == kConstantPoolMarker); 33 return ((instr >> 4) & 0xfff0) | (instr & 0xf); 34 } 35 36 // Used in code age prologue - ldr(pc, MemOperand(pc, -4)) 37 const int kCodeAgeJumpInstruction = 0xe51ff004; 38 39 // Number of registers in normal ARM mode. 40 const int kNumRegisters = 16; 41 42 // VFP support. 43 const int kNumVFPSingleRegisters = 32; 44 const int kNumVFPDoubleRegisters = 32; 45 const int kNumVFPRegisters = kNumVFPSingleRegisters + kNumVFPDoubleRegisters; 46 47 // PC is register 15. 48 const int kPCRegister = 15; 49 const int kNoRegister = -1; 50 51 // Used in embedded constant pool builder - max reach in bits for 52 // various load instructions (unsigned) 53 const int kLdrMaxReachBits = 12; 54 const int kVldrMaxReachBits = 10; 55 56 // ----------------------------------------------------------------------------- 57 // Conditions. 58 59 // Defines constants and accessor classes to assemble, disassemble and 60 // simulate ARM instructions. 61 // 62 // Section references in the code refer to the "ARM Architecture Reference 63 // Manual" from July 2005 (available at http://www.arm.com/miscPDFs/14128.pdf) 64 // 65 // Constants for specific fields are defined in their respective named enums. 66 // General constants are in an anonymous enum in class Instr. 67 68 // Values for the condition field as defined in section A3.2 69 enum Condition { 70 kNoCondition = -1, 71 72 eq = 0 << 28, // Z set Equal. 73 ne = 1 << 28, // Z clear Not equal. 74 cs = 2 << 28, // C set Unsigned higher or same. 75 cc = 3 << 28, // C clear Unsigned lower. 76 mi = 4 << 28, // N set Negative. 77 pl = 5 << 28, // N clear Positive or zero. 78 vs = 6 << 28, // V set Overflow. 79 vc = 7 << 28, // V clear No overflow. 80 hi = 8 << 28, // C set, Z clear Unsigned higher. 81 ls = 9 << 28, // C clear or Z set Unsigned lower or same. 82 ge = 10 << 28, // N == V Greater or equal. 83 lt = 11 << 28, // N != V Less than. 84 gt = 12 << 28, // Z clear, N == V Greater than. 85 le = 13 << 28, // Z set or N != V Less then or equal 86 al = 14 << 28, // Always. 87 88 kSpecialCondition = 15 << 28, // Special condition (refer to section A3.2.1). 89 kNumberOfConditions = 16, 90 91 // Aliases. 92 hs = cs, // C set Unsigned higher or same. 93 lo = cc // C clear Unsigned lower. 94 }; 95 96 97 inline Condition NegateCondition(Condition cond) { 98 DCHECK(cond != al); 99 return static_cast<Condition>(cond ^ ne); 100 } 101 102 103 // Commute a condition such that {a cond b == b cond' a}. 104 inline Condition CommuteCondition(Condition cond) { 105 switch (cond) { 106 case lo: 107 return hi; 108 case hi: 109 return lo; 110 case hs: 111 return ls; 112 case ls: 113 return hs; 114 case lt: 115 return gt; 116 case gt: 117 return lt; 118 case ge: 119 return le; 120 case le: 121 return ge; 122 default: 123 return cond; 124 } 125 } 126 127 128 // ----------------------------------------------------------------------------- 129 // Instructions encoding. 130 131 // Instr is merely used by the Assembler to distinguish 32bit integers 132 // representing instructions from usual 32 bit values. 133 // Instruction objects are pointers to 32bit values, and provide methods to 134 // access the various ISA fields. 135 typedef int32_t Instr; 136 137 138 // Opcodes for Data-processing instructions (instructions with a type 0 and 1) 139 // as defined in section A3.4 140 enum Opcode { 141 AND = 0 << 21, // Logical AND. 142 EOR = 1 << 21, // Logical Exclusive OR. 143 SUB = 2 << 21, // Subtract. 144 RSB = 3 << 21, // Reverse Subtract. 145 ADD = 4 << 21, // Add. 146 ADC = 5 << 21, // Add with Carry. 147 SBC = 6 << 21, // Subtract with Carry. 148 RSC = 7 << 21, // Reverse Subtract with Carry. 149 TST = 8 << 21, // Test. 150 TEQ = 9 << 21, // Test Equivalence. 151 CMP = 10 << 21, // Compare. 152 CMN = 11 << 21, // Compare Negated. 153 ORR = 12 << 21, // Logical (inclusive) OR. 154 MOV = 13 << 21, // Move. 155 BIC = 14 << 21, // Bit Clear. 156 MVN = 15 << 21 // Move Not. 157 }; 158 159 160 // The bits for bit 7-4 for some type 0 miscellaneous instructions. 161 enum MiscInstructionsBits74 { 162 // With bits 22-21 01. 163 BX = 1 << 4, 164 BXJ = 2 << 4, 165 BLX = 3 << 4, 166 BKPT = 7 << 4, 167 168 // With bits 22-21 11. 169 CLZ = 1 << 4 170 }; 171 172 173 // Instruction encoding bits and masks. 174 enum { 175 H = 1 << 5, // Halfword (or byte). 176 S6 = 1 << 6, // Signed (or unsigned). 177 L = 1 << 20, // Load (or store). 178 S = 1 << 20, // Set condition code (or leave unchanged). 179 W = 1 << 21, // Writeback base register (or leave unchanged). 180 A = 1 << 21, // Accumulate in multiply instruction (or not). 181 B = 1 << 22, // Unsigned byte (or word). 182 N = 1 << 22, // Long (or short). 183 U = 1 << 23, // Positive (or negative) offset/index. 184 P = 1 << 24, // Offset/pre-indexed addressing (or post-indexed addressing). 185 I = 1 << 25, // Immediate shifter operand (or not). 186 B0 = 1 << 0, 187 B4 = 1 << 4, 188 B5 = 1 << 5, 189 B6 = 1 << 6, 190 B7 = 1 << 7, 191 B8 = 1 << 8, 192 B9 = 1 << 9, 193 B12 = 1 << 12, 194 B16 = 1 << 16, 195 B17 = 1 << 17, 196 B18 = 1 << 18, 197 B19 = 1 << 19, 198 B20 = 1 << 20, 199 B21 = 1 << 21, 200 B22 = 1 << 22, 201 B23 = 1 << 23, 202 B24 = 1 << 24, 203 B25 = 1 << 25, 204 B26 = 1 << 26, 205 B27 = 1 << 27, 206 B28 = 1 << 28, 207 208 // Instruction bit masks. 209 kCondMask = 15 << 28, 210 kALUMask = 0x6f << 21, 211 kRdMask = 15 << 12, // In str instruction. 212 kCoprocessorMask = 15 << 8, 213 kOpCodeMask = 15 << 21, // In data-processing instructions. 214 kImm24Mask = (1 << 24) - 1, 215 kImm16Mask = (1 << 16) - 1, 216 kImm8Mask = (1 << 8) - 1, 217 kOff12Mask = (1 << 12) - 1, 218 kOff8Mask = (1 << 8) - 1 219 }; 220 221 222 enum BarrierOption { 223 OSHLD = 0x1, 224 OSHST = 0x2, 225 OSH = 0x3, 226 NSHLD = 0x5, 227 NSHST = 0x6, 228 NSH = 0x7, 229 ISHLD = 0x9, 230 ISHST = 0xa, 231 ISH = 0xb, 232 LD = 0xd, 233 ST = 0xe, 234 SY = 0xf, 235 }; 236 237 238 // ----------------------------------------------------------------------------- 239 // Addressing modes and instruction variants. 240 241 // Condition code updating mode. 242 enum SBit { 243 SetCC = 1 << 20, // Set condition code. 244 LeaveCC = 0 << 20 // Leave condition code unchanged. 245 }; 246 247 248 // Status register selection. 249 enum SRegister { 250 CPSR = 0 << 22, 251 SPSR = 1 << 22 252 }; 253 254 255 // Shifter types for Data-processing operands as defined in section A5.1.2. 256 enum ShiftOp { 257 LSL = 0 << 5, // Logical shift left. 258 LSR = 1 << 5, // Logical shift right. 259 ASR = 2 << 5, // Arithmetic shift right. 260 ROR = 3 << 5, // Rotate right. 261 262 // RRX is encoded as ROR with shift_imm == 0. 263 // Use a special code to make the distinction. The RRX ShiftOp is only used 264 // as an argument, and will never actually be encoded. The Assembler will 265 // detect it and emit the correct ROR shift operand with shift_imm == 0. 266 RRX = -1, 267 kNumberOfShifts = 4 268 }; 269 270 271 // Status register fields. 272 enum SRegisterField { 273 CPSR_c = CPSR | 1 << 16, 274 CPSR_x = CPSR | 1 << 17, 275 CPSR_s = CPSR | 1 << 18, 276 CPSR_f = CPSR | 1 << 19, 277 SPSR_c = SPSR | 1 << 16, 278 SPSR_x = SPSR | 1 << 17, 279 SPSR_s = SPSR | 1 << 18, 280 SPSR_f = SPSR | 1 << 19 281 }; 282 283 // Status register field mask (or'ed SRegisterField enum values). 284 typedef uint32_t SRegisterFieldMask; 285 286 287 // Memory operand addressing mode. 288 enum AddrMode { 289 // Bit encoding P U W. 290 Offset = (8|4|0) << 21, // Offset (without writeback to base). 291 PreIndex = (8|4|1) << 21, // Pre-indexed addressing with writeback. 292 PostIndex = (0|4|0) << 21, // Post-indexed addressing with writeback. 293 NegOffset = (8|0|0) << 21, // Negative offset (without writeback to base). 294 NegPreIndex = (8|0|1) << 21, // Negative pre-indexed with writeback. 295 NegPostIndex = (0|0|0) << 21 // Negative post-indexed with writeback. 296 }; 297 298 299 // Load/store multiple addressing mode. 300 enum BlockAddrMode { 301 // Bit encoding P U W . 302 da = (0|0|0) << 21, // Decrement after. 303 ia = (0|4|0) << 21, // Increment after. 304 db = (8|0|0) << 21, // Decrement before. 305 ib = (8|4|0) << 21, // Increment before. 306 da_w = (0|0|1) << 21, // Decrement after with writeback to base. 307 ia_w = (0|4|1) << 21, // Increment after with writeback to base. 308 db_w = (8|0|1) << 21, // Decrement before with writeback to base. 309 ib_w = (8|4|1) << 21, // Increment before with writeback to base. 310 311 // Alias modes for comparison when writeback does not matter. 312 da_x = (0|0|0) << 21, // Decrement after. 313 ia_x = (0|4|0) << 21, // Increment after. 314 db_x = (8|0|0) << 21, // Decrement before. 315 ib_x = (8|4|0) << 21, // Increment before. 316 317 kBlockAddrModeMask = (8|4|1) << 21 318 }; 319 320 321 // Coprocessor load/store operand size. 322 enum LFlag { 323 Long = 1 << 22, // Long load/store coprocessor. 324 Short = 0 << 22 // Short load/store coprocessor. 325 }; 326 327 328 // NEON data type 329 enum NeonDataType { 330 NeonS8 = 0x1, // U = 0, imm3 = 0b001 331 NeonS16 = 0x2, // U = 0, imm3 = 0b010 332 NeonS32 = 0x4, // U = 0, imm3 = 0b100 333 NeonU8 = 1 << 24 | 0x1, // U = 1, imm3 = 0b001 334 NeonU16 = 1 << 24 | 0x2, // U = 1, imm3 = 0b010 335 NeonU32 = 1 << 24 | 0x4, // U = 1, imm3 = 0b100 336 NeonDataTypeSizeMask = 0x7, 337 NeonDataTypeUMask = 1 << 24 338 }; 339 340 enum NeonListType { 341 nlt_1 = 0x7, 342 nlt_2 = 0xA, 343 nlt_3 = 0x6, 344 nlt_4 = 0x2 345 }; 346 347 enum NeonSize { 348 Neon8 = 0x0, 349 Neon16 = 0x1, 350 Neon32 = 0x2, 351 Neon64 = 0x3 352 }; 353 354 // ----------------------------------------------------------------------------- 355 // Supervisor Call (svc) specific support. 356 357 // Special Software Interrupt codes when used in the presence of the ARM 358 // simulator. 359 // svc (formerly swi) provides a 24bit immediate value. Use bits 22:0 for 360 // standard SoftwareInterrupCode. Bit 23 is reserved for the stop feature. 361 enum SoftwareInterruptCodes { 362 // transition to C code 363 kCallRtRedirected = 0x10, 364 // break point 365 kBreakpoint = 0x20, 366 // stop 367 kStopCode = 1 << 23 368 }; 369 const uint32_t kStopCodeMask = kStopCode - 1; 370 const uint32_t kMaxStopCode = kStopCode - 1; 371 const int32_t kDefaultStopCode = -1; 372 373 374 // Type of VFP register. Determines register encoding. 375 enum VFPRegPrecision { 376 kSinglePrecision = 0, 377 kDoublePrecision = 1 378 }; 379 380 381 // VFP FPSCR constants. 382 enum VFPConversionMode { 383 kFPSCRRounding = 0, 384 kDefaultRoundToZero = 1 385 }; 386 387 // This mask does not include the "inexact" or "input denormal" cumulative 388 // exceptions flags, because we usually don't want to check for it. 389 const uint32_t kVFPExceptionMask = 0xf; 390 const uint32_t kVFPInvalidOpExceptionBit = 1 << 0; 391 const uint32_t kVFPOverflowExceptionBit = 1 << 2; 392 const uint32_t kVFPUnderflowExceptionBit = 1 << 3; 393 const uint32_t kVFPInexactExceptionBit = 1 << 4; 394 const uint32_t kVFPFlushToZeroMask = 1 << 24; 395 const uint32_t kVFPDefaultNaNModeControlBit = 1 << 25; 396 397 const uint32_t kVFPNConditionFlagBit = 1 << 31; 398 const uint32_t kVFPZConditionFlagBit = 1 << 30; 399 const uint32_t kVFPCConditionFlagBit = 1 << 29; 400 const uint32_t kVFPVConditionFlagBit = 1 << 28; 401 402 403 // VFP rounding modes. See ARM DDI 0406B Page A2-29. 404 enum VFPRoundingMode { 405 RN = 0 << 22, // Round to Nearest. 406 RP = 1 << 22, // Round towards Plus Infinity. 407 RM = 2 << 22, // Round towards Minus Infinity. 408 RZ = 3 << 22, // Round towards zero. 409 410 // Aliases. 411 kRoundToNearest = RN, 412 kRoundToPlusInf = RP, 413 kRoundToMinusInf = RM, 414 kRoundToZero = RZ 415 }; 416 417 const uint32_t kVFPRoundingModeMask = 3 << 22; 418 419 enum CheckForInexactConversion { 420 kCheckForInexactConversion, 421 kDontCheckForInexactConversion 422 }; 423 424 // ----------------------------------------------------------------------------- 425 // Hints. 426 427 // Branch hints are not used on the ARM. They are defined so that they can 428 // appear in shared function signatures, but will be ignored in ARM 429 // implementations. 430 enum Hint { no_hint }; 431 432 // Hints are not used on the arm. Negating is trivial. 433 inline Hint NegateHint(Hint ignored) { return no_hint; } 434 435 436 // ----------------------------------------------------------------------------- 437 // Instruction abstraction. 438 439 // The class Instruction enables access to individual fields defined in the ARM 440 // architecture instruction set encoding as described in figure A3-1. 441 // Note that the Assembler uses typedef int32_t Instr. 442 // 443 // Example: Test whether the instruction at ptr does set the condition code 444 // bits. 445 // 446 // bool InstructionSetsConditionCodes(byte* ptr) { 447 // Instruction* instr = Instruction::At(ptr); 448 // int type = instr->TypeValue(); 449 // return ((type == 0) || (type == 1)) && instr->HasS(); 450 // } 451 // 452 class Instruction { 453 public: 454 enum { 455 kInstrSize = 4, 456 kInstrSizeLog2 = 2, 457 kPCReadOffset = 8 458 }; 459 460 // Helper macro to define static accessors. 461 // We use the cast to char* trick to bypass the strict anti-aliasing rules. 462 #define DECLARE_STATIC_TYPED_ACCESSOR(return_type, Name) \ 463 static inline return_type Name(Instr instr) { \ 464 char* temp = reinterpret_cast<char*>(&instr); \ 465 return reinterpret_cast<Instruction*>(temp)->Name(); \ 466 } 467 468 #define DECLARE_STATIC_ACCESSOR(Name) DECLARE_STATIC_TYPED_ACCESSOR(int, Name) 469 470 // Get the raw instruction bits. 471 inline Instr InstructionBits() const { 472 return *reinterpret_cast<const Instr*>(this); 473 } 474 475 // Set the raw instruction bits to value. 476 inline void SetInstructionBits(Instr value) { 477 *reinterpret_cast<Instr*>(this) = value; 478 } 479 480 // Read one particular bit out of the instruction bits. 481 inline int Bit(int nr) const { 482 return (InstructionBits() >> nr) & 1; 483 } 484 485 // Read a bit field's value out of the instruction bits. 486 inline int Bits(int hi, int lo) const { 487 return (InstructionBits() >> lo) & ((2 << (hi - lo)) - 1); 488 } 489 490 // Read a bit field out of the instruction bits. 491 inline int BitField(int hi, int lo) const { 492 return InstructionBits() & (((2 << (hi - lo)) - 1) << lo); 493 } 494 495 // Static support. 496 497 // Read one particular bit out of the instruction bits. 498 static inline int Bit(Instr instr, int nr) { 499 return (instr >> nr) & 1; 500 } 501 502 // Read the value of a bit field out of the instruction bits. 503 static inline int Bits(Instr instr, int hi, int lo) { 504 return (instr >> lo) & ((2 << (hi - lo)) - 1); 505 } 506 507 508 // Read a bit field out of the instruction bits. 509 static inline int BitField(Instr instr, int hi, int lo) { 510 return instr & (((2 << (hi - lo)) - 1) << lo); 511 } 512 513 514 // Accessors for the different named fields used in the ARM encoding. 515 // The naming of these accessor corresponds to figure A3-1. 516 // 517 // Two kind of accessors are declared: 518 // - <Name>Field() will return the raw field, i.e. the field's bits at their 519 // original place in the instruction encoding. 520 // e.g. if instr is the 'addgt r0, r1, r2' instruction, encoded as 521 // 0xC0810002 ConditionField(instr) will return 0xC0000000. 522 // - <Name>Value() will return the field value, shifted back to bit 0. 523 // e.g. if instr is the 'addgt r0, r1, r2' instruction, encoded as 524 // 0xC0810002 ConditionField(instr) will return 0xC. 525 526 527 // Generally applicable fields 528 inline Condition ConditionValue() const { 529 return static_cast<Condition>(Bits(31, 28)); 530 } 531 inline Condition ConditionField() const { 532 return static_cast<Condition>(BitField(31, 28)); 533 } 534 DECLARE_STATIC_TYPED_ACCESSOR(Condition, ConditionValue); 535 DECLARE_STATIC_TYPED_ACCESSOR(Condition, ConditionField); 536 537 inline int TypeValue() const { return Bits(27, 25); } 538 inline int SpecialValue() const { return Bits(27, 23); } 539 540 inline int RnValue() const { return Bits(19, 16); } 541 DECLARE_STATIC_ACCESSOR(RnValue); 542 inline int RdValue() const { return Bits(15, 12); } 543 DECLARE_STATIC_ACCESSOR(RdValue); 544 545 inline int CoprocessorValue() const { return Bits(11, 8); } 546 // Support for VFP. 547 // Vn(19-16) | Vd(15-12) | Vm(3-0) 548 inline int VnValue() const { return Bits(19, 16); } 549 inline int VmValue() const { return Bits(3, 0); } 550 inline int VdValue() const { return Bits(15, 12); } 551 inline int NValue() const { return Bit(7); } 552 inline int MValue() const { return Bit(5); } 553 inline int DValue() const { return Bit(22); } 554 inline int RtValue() const { return Bits(15, 12); } 555 inline int PValue() const { return Bit(24); } 556 inline int UValue() const { return Bit(23); } 557 inline int Opc1Value() const { return (Bit(23) << 2) | Bits(21, 20); } 558 inline int Opc2Value() const { return Bits(19, 16); } 559 inline int Opc3Value() const { return Bits(7, 6); } 560 inline int SzValue() const { return Bit(8); } 561 inline int VLValue() const { return Bit(20); } 562 inline int VCValue() const { return Bit(8); } 563 inline int VAValue() const { return Bits(23, 21); } 564 inline int VBValue() const { return Bits(6, 5); } 565 inline int VFPNRegValue(VFPRegPrecision pre) { 566 return VFPGlueRegValue(pre, 16, 7); 567 } 568 inline int VFPMRegValue(VFPRegPrecision pre) { 569 return VFPGlueRegValue(pre, 0, 5); 570 } 571 inline int VFPDRegValue(VFPRegPrecision pre) { 572 return VFPGlueRegValue(pre, 12, 22); 573 } 574 575 // Fields used in Data processing instructions 576 inline int OpcodeValue() const { 577 return static_cast<Opcode>(Bits(24, 21)); 578 } 579 inline Opcode OpcodeField() const { 580 return static_cast<Opcode>(BitField(24, 21)); 581 } 582 inline int SValue() const { return Bit(20); } 583 // with register 584 inline int RmValue() const { return Bits(3, 0); } 585 DECLARE_STATIC_ACCESSOR(RmValue); 586 inline int ShiftValue() const { return static_cast<ShiftOp>(Bits(6, 5)); } 587 inline ShiftOp ShiftField() const { 588 return static_cast<ShiftOp>(BitField(6, 5)); 589 } 590 inline int RegShiftValue() const { return Bit(4); } 591 inline int RsValue() const { return Bits(11, 8); } 592 inline int ShiftAmountValue() const { return Bits(11, 7); } 593 // with immediate 594 inline int RotateValue() const { return Bits(11, 8); } 595 DECLARE_STATIC_ACCESSOR(RotateValue); 596 inline int Immed8Value() const { return Bits(7, 0); } 597 DECLARE_STATIC_ACCESSOR(Immed8Value); 598 inline int Immed4Value() const { return Bits(19, 16); } 599 inline int ImmedMovwMovtValue() const { 600 return Immed4Value() << 12 | Offset12Value(); } 601 DECLARE_STATIC_ACCESSOR(ImmedMovwMovtValue); 602 603 // Fields used in Load/Store instructions 604 inline int PUValue() const { return Bits(24, 23); } 605 inline int PUField() const { return BitField(24, 23); } 606 inline int BValue() const { return Bit(22); } 607 inline int WValue() const { return Bit(21); } 608 inline int LValue() const { return Bit(20); } 609 // with register uses same fields as Data processing instructions above 610 // with immediate 611 inline int Offset12Value() const { return Bits(11, 0); } 612 // multiple 613 inline int RlistValue() const { return Bits(15, 0); } 614 // extra loads and stores 615 inline int SignValue() const { return Bit(6); } 616 inline int HValue() const { return Bit(5); } 617 inline int ImmedHValue() const { return Bits(11, 8); } 618 inline int ImmedLValue() const { return Bits(3, 0); } 619 620 // Fields used in Branch instructions 621 inline int LinkValue() const { return Bit(24); } 622 inline int SImmed24Value() const { return ((InstructionBits() << 8) >> 8); } 623 624 // Fields used in Software interrupt instructions 625 inline SoftwareInterruptCodes SvcValue() const { 626 return static_cast<SoftwareInterruptCodes>(Bits(23, 0)); 627 } 628 629 // Test for special encodings of type 0 instructions (extra loads and stores, 630 // as well as multiplications). 631 inline bool IsSpecialType0() const { return (Bit(7) == 1) && (Bit(4) == 1); } 632 633 // Test for miscellaneous instructions encodings of type 0 instructions. 634 inline bool IsMiscType0() const { return (Bit(24) == 1) 635 && (Bit(23) == 0) 636 && (Bit(20) == 0) 637 && ((Bit(7) == 0)); } 638 639 // Test for a nop instruction, which falls under type 1. 640 inline bool IsNopType1() const { return Bits(24, 0) == 0x0120F000; } 641 642 // Test for a stop instruction. 643 inline bool IsStop() const { 644 return (TypeValue() == 7) && (Bit(24) == 1) && (SvcValue() >= kStopCode); 645 } 646 647 // Special accessors that test for existence of a value. 648 inline bool HasS() const { return SValue() == 1; } 649 inline bool HasB() const { return BValue() == 1; } 650 inline bool HasW() const { return WValue() == 1; } 651 inline bool HasL() const { return LValue() == 1; } 652 inline bool HasU() const { return UValue() == 1; } 653 inline bool HasSign() const { return SignValue() == 1; } 654 inline bool HasH() const { return HValue() == 1; } 655 inline bool HasLink() const { return LinkValue() == 1; } 656 657 // Decode the double immediate from a vmov instruction. 658 double DoubleImmedVmov() const; 659 660 // Instructions are read of out a code stream. The only way to get a 661 // reference to an instruction is to convert a pointer. There is no way 662 // to allocate or create instances of class Instruction. 663 // Use the At(pc) function to create references to Instruction. 664 static Instruction* At(byte* pc) { 665 return reinterpret_cast<Instruction*>(pc); 666 } 667 668 669 private: 670 // Join split register codes, depending on single or double precision. 671 // four_bit is the position of the least-significant bit of the four 672 // bit specifier. one_bit is the position of the additional single bit 673 // specifier. 674 inline int VFPGlueRegValue(VFPRegPrecision pre, int four_bit, int one_bit) { 675 if (pre == kSinglePrecision) { 676 return (Bits(four_bit + 3, four_bit) << 1) | Bit(one_bit); 677 } 678 return (Bit(one_bit) << 4) | Bits(four_bit + 3, four_bit); 679 } 680 681 // We need to prevent the creation of instances of class Instruction. 682 DISALLOW_IMPLICIT_CONSTRUCTORS(Instruction); 683 }; 684 685 686 // Helper functions for converting between register numbers and names. 687 class Registers { 688 public: 689 // Return the name of the register. 690 static const char* Name(int reg); 691 692 // Lookup the register number for the name provided. 693 static int Number(const char* name); 694 695 struct RegisterAlias { 696 int reg; 697 const char* name; 698 }; 699 700 private: 701 static const char* names_[kNumRegisters]; 702 static const RegisterAlias aliases_[]; 703 }; 704 705 // Helper functions for converting between VFP register numbers and names. 706 class VFPRegisters { 707 public: 708 // Return the name of the register. 709 static const char* Name(int reg, bool is_double); 710 711 // Lookup the register number for the name provided. 712 // Set flag pointed by is_double to true if register 713 // is double-precision. 714 static int Number(const char* name, bool* is_double); 715 716 private: 717 static const char* names_[kNumVFPRegisters]; 718 }; 719 720 721 } // namespace internal 722 } // namespace v8 723 724 #endif // V8_ARM_CONSTANTS_ARM_H_ 725
