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