xref: /llvm-project/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp (revision 4d3e3f279e736ee1ecf997952d9ac4b5bd51f0e0)
1 //===-- ARMDisassembler.cpp - Disassembler for ARM/Thumb ISA --------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #define DEBUG_TYPE "arm-disassembler"
11 
12 #include "llvm/MC/MCDisassembler.h"
13 #include "MCTargetDesc/ARMAddressingModes.h"
14 #include "MCTargetDesc/ARMBaseInfo.h"
15 #include "MCTargetDesc/ARMMCExpr.h"
16 #include "llvm/MC/MCContext.h"
17 #include "llvm/MC/MCExpr.h"
18 #include "llvm/MC/MCFixedLenDisassembler.h"
19 #include "llvm/MC/MCInst.h"
20 #include "llvm/MC/MCInstrDesc.h"
21 #include "llvm/MC/MCSubtargetInfo.h"
22 #include "llvm/Support/Debug.h"
23 #include "llvm/Support/ErrorHandling.h"
24 #include "llvm/Support/LEB128.h"
25 #include "llvm/Support/MemoryObject.h"
26 #include "llvm/Support/TargetRegistry.h"
27 #include "llvm/Support/raw_ostream.h"
28 #include <vector>
29 
30 using namespace llvm;
31 
32 typedef MCDisassembler::DecodeStatus DecodeStatus;
33 
34 namespace {
35   // Handles the condition code status of instructions in IT blocks
36   class ITStatus
37   {
38     public:
39       // Returns the condition code for instruction in IT block
40       unsigned getITCC() {
41         unsigned CC = ARMCC::AL;
42         if (instrInITBlock())
43           CC = ITStates.back();
44         return CC;
45       }
46 
47       // Advances the IT block state to the next T or E
48       void advanceITState() {
49         ITStates.pop_back();
50       }
51 
52       // Returns true if the current instruction is in an IT block
53       bool instrInITBlock() {
54         return !ITStates.empty();
55       }
56 
57       // Returns true if current instruction is the last instruction in an IT block
58       bool instrLastInITBlock() {
59         return ITStates.size() == 1;
60       }
61 
62       // Called when decoding an IT instruction. Sets the IT state for the following
63       // instructions that for the IT block. Firstcond and Mask correspond to the
64       // fields in the IT instruction encoding.
65       void setITState(char Firstcond, char Mask) {
66         // (3 - the number of trailing zeros) is the number of then / else.
67         unsigned CondBit0 = Firstcond & 1;
68         unsigned NumTZ = countTrailingZeros<uint8_t>(Mask);
69         unsigned char CCBits = static_cast<unsigned char>(Firstcond & 0xf);
70         assert(NumTZ <= 3 && "Invalid IT mask!");
71         // push condition codes onto the stack the correct order for the pops
72         for (unsigned Pos = NumTZ+1; Pos <= 3; ++Pos) {
73           bool T = ((Mask >> Pos) & 1) == CondBit0;
74           if (T)
75             ITStates.push_back(CCBits);
76           else
77             ITStates.push_back(CCBits ^ 1);
78         }
79         ITStates.push_back(CCBits);
80       }
81 
82     private:
83       std::vector<unsigned char> ITStates;
84   };
85 }
86 
87 namespace {
88 /// ARMDisassembler - ARM disassembler for all ARM platforms.
89 class ARMDisassembler : public MCDisassembler {
90 public:
91   /// Constructor     - Initializes the disassembler.
92   ///
93   ARMDisassembler(const MCSubtargetInfo &STI) :
94     MCDisassembler(STI) {
95   }
96 
97   ~ARMDisassembler() {
98   }
99 
100   /// getInstruction - See MCDisassembler.
101   DecodeStatus getInstruction(MCInst &instr,
102                               uint64_t &size,
103                               const MemoryObject &region,
104                               uint64_t address,
105                               raw_ostream &vStream,
106                               raw_ostream &cStream) const;
107 };
108 
109 /// ThumbDisassembler - Thumb disassembler for all Thumb platforms.
110 class ThumbDisassembler : public MCDisassembler {
111 public:
112   /// Constructor     - Initializes the disassembler.
113   ///
114   ThumbDisassembler(const MCSubtargetInfo &STI) :
115     MCDisassembler(STI) {
116   }
117 
118   ~ThumbDisassembler() {
119   }
120 
121   /// getInstruction - See MCDisassembler.
122   DecodeStatus getInstruction(MCInst &instr,
123                               uint64_t &size,
124                               const MemoryObject &region,
125                               uint64_t address,
126                               raw_ostream &vStream,
127                               raw_ostream &cStream) const;
128 
129 private:
130   mutable ITStatus ITBlock;
131   DecodeStatus AddThumbPredicate(MCInst&) const;
132   void UpdateThumbVFPPredicate(MCInst&) const;
133 };
134 }
135 
136 static bool Check(DecodeStatus &Out, DecodeStatus In) {
137   switch (In) {
138     case MCDisassembler::Success:
139       // Out stays the same.
140       return true;
141     case MCDisassembler::SoftFail:
142       Out = In;
143       return true;
144     case MCDisassembler::Fail:
145       Out = In;
146       return false;
147   }
148   llvm_unreachable("Invalid DecodeStatus!");
149 }
150 
151 
152 // Forward declare these because the autogenerated code will reference them.
153 // Definitions are further down.
154 static DecodeStatus DecodeGPRRegisterClass(MCInst &Inst, unsigned RegNo,
155                                    uint64_t Address, const void *Decoder);
156 static DecodeStatus DecodeGPRnopcRegisterClass(MCInst &Inst,
157                                                unsigned RegNo, uint64_t Address,
158                                                const void *Decoder);
159 static DecodeStatus DecodeGPRwithAPSRRegisterClass(MCInst &Inst,
160                                                unsigned RegNo, uint64_t Address,
161                                                const void *Decoder);
162 static DecodeStatus DecodetGPRRegisterClass(MCInst &Inst, unsigned RegNo,
163                                    uint64_t Address, const void *Decoder);
164 static DecodeStatus DecodetcGPRRegisterClass(MCInst &Inst, unsigned RegNo,
165                                    uint64_t Address, const void *Decoder);
166 static DecodeStatus DecoderGPRRegisterClass(MCInst &Inst, unsigned RegNo,
167                                    uint64_t Address, const void *Decoder);
168 static DecodeStatus DecodeGPRPairRegisterClass(MCInst &Inst, unsigned RegNo,
169                                    uint64_t Address, const void *Decoder);
170 static DecodeStatus DecodeSPRRegisterClass(MCInst &Inst, unsigned RegNo,
171                                    uint64_t Address, const void *Decoder);
172 static DecodeStatus DecodeDPRRegisterClass(MCInst &Inst, unsigned RegNo,
173                                    uint64_t Address, const void *Decoder);
174 static DecodeStatus DecodeDPR_8RegisterClass(MCInst &Inst, unsigned RegNo,
175                                    uint64_t Address, const void *Decoder);
176 static DecodeStatus DecodeDPR_VFP2RegisterClass(MCInst &Inst,
177                                                 unsigned RegNo,
178                                                 uint64_t Address,
179                                                 const void *Decoder);
180 static DecodeStatus DecodeQPRRegisterClass(MCInst &Inst, unsigned RegNo,
181                                    uint64_t Address, const void *Decoder);
182 static DecodeStatus DecodeDPairRegisterClass(MCInst &Inst, unsigned RegNo,
183                                    uint64_t Address, const void *Decoder);
184 static DecodeStatus DecodeDPairSpacedRegisterClass(MCInst &Inst,
185                                unsigned RegNo, uint64_t Address,
186                                const void *Decoder);
187 
188 static DecodeStatus DecodePredicateOperand(MCInst &Inst, unsigned Val,
189                                uint64_t Address, const void *Decoder);
190 static DecodeStatus DecodeCCOutOperand(MCInst &Inst, unsigned Val,
191                                uint64_t Address, const void *Decoder);
192 static DecodeStatus DecodeSOImmOperand(MCInst &Inst, unsigned Val,
193                                uint64_t Address, const void *Decoder);
194 static DecodeStatus DecodeRegListOperand(MCInst &Inst, unsigned Val,
195                                uint64_t Address, const void *Decoder);
196 static DecodeStatus DecodeSPRRegListOperand(MCInst &Inst, unsigned Val,
197                                uint64_t Address, const void *Decoder);
198 static DecodeStatus DecodeDPRRegListOperand(MCInst &Inst, unsigned Val,
199                                uint64_t Address, const void *Decoder);
200 
201 static DecodeStatus DecodeBitfieldMaskOperand(MCInst &Inst, unsigned Insn,
202                                uint64_t Address, const void *Decoder);
203 static DecodeStatus DecodeCopMemInstruction(MCInst &Inst, unsigned Insn,
204                                uint64_t Address, const void *Decoder);
205 static DecodeStatus DecodeAddrMode2IdxInstruction(MCInst &Inst,
206                                                   unsigned Insn,
207                                                   uint64_t Address,
208                                                   const void *Decoder);
209 static DecodeStatus DecodeSORegMemOperand(MCInst &Inst, unsigned Insn,
210                                uint64_t Address, const void *Decoder);
211 static DecodeStatus DecodeAddrMode3Instruction(MCInst &Inst,unsigned Insn,
212                                uint64_t Address, const void *Decoder);
213 static DecodeStatus DecodeSORegImmOperand(MCInst &Inst, unsigned Insn,
214                                uint64_t Address, const void *Decoder);
215 static DecodeStatus DecodeSORegRegOperand(MCInst &Inst, unsigned Insn,
216                                uint64_t Address, const void *Decoder);
217 
218 static DecodeStatus DecodeMemMultipleWritebackInstruction(MCInst & Inst,
219                                                   unsigned Insn,
220                                                   uint64_t Adddress,
221                                                   const void *Decoder);
222 static DecodeStatus DecodeT2MOVTWInstruction(MCInst &Inst, unsigned Insn,
223                                uint64_t Address, const void *Decoder);
224 static DecodeStatus DecodeArmMOVTWInstruction(MCInst &Inst, unsigned Insn,
225                                uint64_t Address, const void *Decoder);
226 static DecodeStatus DecodeSMLAInstruction(MCInst &Inst, unsigned Insn,
227                                uint64_t Address, const void *Decoder);
228 static DecodeStatus DecodeCPSInstruction(MCInst &Inst, unsigned Insn,
229                                uint64_t Address, const void *Decoder);
230 static DecodeStatus DecodeT2CPSInstruction(MCInst &Inst, unsigned Insn,
231                                uint64_t Address, const void *Decoder);
232 static DecodeStatus DecodeAddrModeImm12Operand(MCInst &Inst, unsigned Val,
233                                uint64_t Address, const void *Decoder);
234 static DecodeStatus DecodeAddrMode5Operand(MCInst &Inst, unsigned Val,
235                                uint64_t Address, const void *Decoder);
236 static DecodeStatus DecodeAddrMode7Operand(MCInst &Inst, unsigned Val,
237                                uint64_t Address, const void *Decoder);
238 static DecodeStatus DecodeT2BInstruction(MCInst &Inst, unsigned Insn,
239                                uint64_t Address, const void *Decoder);
240 static DecodeStatus DecodeBranchImmInstruction(MCInst &Inst,unsigned Insn,
241                                uint64_t Address, const void *Decoder);
242 static DecodeStatus DecodeAddrMode6Operand(MCInst &Inst, unsigned Val,
243                                uint64_t Address, const void *Decoder);
244 static DecodeStatus DecodeVLDST1Instruction(MCInst &Inst, unsigned Val,
245                                uint64_t Address, const void *Decoder);
246 static DecodeStatus DecodeVLDST2Instruction(MCInst &Inst, unsigned Val,
247                                uint64_t Address, const void *Decoder);
248 static DecodeStatus DecodeVLDST3Instruction(MCInst &Inst, unsigned Val,
249                                uint64_t Address, const void *Decoder);
250 static DecodeStatus DecodeVLDST4Instruction(MCInst &Inst, unsigned Val,
251                                uint64_t Address, const void *Decoder);
252 static DecodeStatus DecodeVLDInstruction(MCInst &Inst, unsigned Val,
253                                uint64_t Address, const void *Decoder);
254 static DecodeStatus DecodeVSTInstruction(MCInst &Inst, unsigned Val,
255                                uint64_t Address, const void *Decoder);
256 static DecodeStatus DecodeVLD1DupInstruction(MCInst &Inst, unsigned Val,
257                                uint64_t Address, const void *Decoder);
258 static DecodeStatus DecodeVLD2DupInstruction(MCInst &Inst, unsigned Val,
259                                uint64_t Address, const void *Decoder);
260 static DecodeStatus DecodeVLD3DupInstruction(MCInst &Inst, unsigned Val,
261                                uint64_t Address, const void *Decoder);
262 static DecodeStatus DecodeVLD4DupInstruction(MCInst &Inst, unsigned Val,
263                                uint64_t Address, const void *Decoder);
264 static DecodeStatus DecodeNEONModImmInstruction(MCInst &Inst,unsigned Val,
265                                uint64_t Address, const void *Decoder);
266 static DecodeStatus DecodeVSHLMaxInstruction(MCInst &Inst, unsigned Val,
267                                uint64_t Address, const void *Decoder);
268 static DecodeStatus DecodeShiftRight8Imm(MCInst &Inst, unsigned Val,
269                                uint64_t Address, const void *Decoder);
270 static DecodeStatus DecodeShiftRight16Imm(MCInst &Inst, unsigned Val,
271                                uint64_t Address, const void *Decoder);
272 static DecodeStatus DecodeShiftRight32Imm(MCInst &Inst, unsigned Val,
273                                uint64_t Address, const void *Decoder);
274 static DecodeStatus DecodeShiftRight64Imm(MCInst &Inst, unsigned Val,
275                                uint64_t Address, const void *Decoder);
276 static DecodeStatus DecodeTBLInstruction(MCInst &Inst, unsigned Insn,
277                                uint64_t Address, const void *Decoder);
278 static DecodeStatus DecodePostIdxReg(MCInst &Inst, unsigned Insn,
279                                uint64_t Address, const void *Decoder);
280 static DecodeStatus DecodeCoprocessor(MCInst &Inst, unsigned Insn,
281                                uint64_t Address, const void *Decoder);
282 static DecodeStatus DecodeMemBarrierOption(MCInst &Inst, unsigned Insn,
283                                uint64_t Address, const void *Decoder);
284 static DecodeStatus DecodeInstSyncBarrierOption(MCInst &Inst, unsigned Insn,
285                                uint64_t Address, const void *Decoder);
286 static DecodeStatus DecodeMSRMask(MCInst &Inst, unsigned Insn,
287                                uint64_t Address, const void *Decoder);
288 static DecodeStatus DecodeDoubleRegLoad(MCInst &Inst, unsigned Insn,
289                                uint64_t Address, const void *Decoder);
290 static DecodeStatus DecodeDoubleRegStore(MCInst &Inst, unsigned Insn,
291                                uint64_t Address, const void *Decoder);
292 static DecodeStatus DecodeLDRPreImm(MCInst &Inst, unsigned Insn,
293                                uint64_t Address, const void *Decoder);
294 static DecodeStatus DecodeLDRPreReg(MCInst &Inst, unsigned Insn,
295                                uint64_t Address, const void *Decoder);
296 static DecodeStatus DecodeSTRPreImm(MCInst &Inst, unsigned Insn,
297                                uint64_t Address, const void *Decoder);
298 static DecodeStatus DecodeSTRPreReg(MCInst &Inst, unsigned Insn,
299                                uint64_t Address, const void *Decoder);
300 static DecodeStatus DecodeVLD1LN(MCInst &Inst, unsigned Insn,
301                                uint64_t Address, const void *Decoder);
302 static DecodeStatus DecodeVLD2LN(MCInst &Inst, unsigned Insn,
303                                uint64_t Address, const void *Decoder);
304 static DecodeStatus DecodeVLD3LN(MCInst &Inst, unsigned Insn,
305                                uint64_t Address, const void *Decoder);
306 static DecodeStatus DecodeVLD4LN(MCInst &Inst, unsigned Insn,
307                                uint64_t Address, const void *Decoder);
308 static DecodeStatus DecodeVST1LN(MCInst &Inst, unsigned Insn,
309                                uint64_t Address, const void *Decoder);
310 static DecodeStatus DecodeVST2LN(MCInst &Inst, unsigned Insn,
311                                uint64_t Address, const void *Decoder);
312 static DecodeStatus DecodeVST3LN(MCInst &Inst, unsigned Insn,
313                                uint64_t Address, const void *Decoder);
314 static DecodeStatus DecodeVST4LN(MCInst &Inst, unsigned Insn,
315                                uint64_t Address, const void *Decoder);
316 static DecodeStatus DecodeVMOVSRR(MCInst &Inst, unsigned Insn,
317                                uint64_t Address, const void *Decoder);
318 static DecodeStatus DecodeVMOVRRS(MCInst &Inst, unsigned Insn,
319                                uint64_t Address, const void *Decoder);
320 static DecodeStatus DecodeSwap(MCInst &Inst, unsigned Insn,
321                                uint64_t Address, const void *Decoder);
322 static DecodeStatus DecodeVCVTD(MCInst &Inst, unsigned Insn,
323                                 uint64_t Address, const void *Decoder);
324 static DecodeStatus DecodeVCVTQ(MCInst &Inst, unsigned Insn,
325                                 uint64_t Address, const void *Decoder);
326 static DecodeStatus DecodeImm0_4(MCInst &Inst, unsigned Insn, uint64_t Address,
327                                  const void *Decoder);
328 
329 
330 static DecodeStatus DecodeThumbAddSpecialReg(MCInst &Inst, uint16_t Insn,
331                                uint64_t Address, const void *Decoder);
332 static DecodeStatus DecodeThumbBROperand(MCInst &Inst, unsigned Val,
333                                uint64_t Address, const void *Decoder);
334 static DecodeStatus DecodeT2BROperand(MCInst &Inst, unsigned Val,
335                                uint64_t Address, const void *Decoder);
336 static DecodeStatus DecodeThumbCmpBROperand(MCInst &Inst, unsigned Val,
337                                uint64_t Address, const void *Decoder);
338 static DecodeStatus DecodeThumbAddrModeRR(MCInst &Inst, unsigned Val,
339                                uint64_t Address, const void *Decoder);
340 static DecodeStatus DecodeThumbAddrModeIS(MCInst &Inst, unsigned Val,
341                                uint64_t Address, const void *Decoder);
342 static DecodeStatus DecodeThumbAddrModePC(MCInst &Inst, unsigned Val,
343                                uint64_t Address, const void *Decoder);
344 static DecodeStatus DecodeThumbAddrModeSP(MCInst &Inst, unsigned Val,
345                                uint64_t Address, const void *Decoder);
346 static DecodeStatus DecodeT2AddrModeSOReg(MCInst &Inst, unsigned Val,
347                                uint64_t Address, const void *Decoder);
348 static DecodeStatus DecodeT2LoadShift(MCInst &Inst, unsigned Val,
349                                uint64_t Address, const void *Decoder);
350 static DecodeStatus DecodeT2LoadImm8(MCInst &Inst, unsigned Insn,
351                                uint64_t Address, const void* Decoder);
352 static DecodeStatus DecodeT2LoadImm12(MCInst &Inst, unsigned Insn,
353                                uint64_t Address, const void* Decoder);
354 static DecodeStatus DecodeT2LoadT(MCInst &Inst, unsigned Insn,
355                                uint64_t Address, const void* Decoder);
356 static DecodeStatus DecodeT2LoadLabel(MCInst &Inst, unsigned Insn,
357                                uint64_t Address, const void* Decoder);
358 static DecodeStatus DecodeT2Imm8S4(MCInst &Inst, unsigned Val,
359                                uint64_t Address, const void *Decoder);
360 static DecodeStatus DecodeT2AddrModeImm8s4(MCInst &Inst, unsigned Val,
361                                uint64_t Address, const void *Decoder);
362 static DecodeStatus DecodeT2AddrModeImm0_1020s4(MCInst &Inst,unsigned Val,
363                                uint64_t Address, const void *Decoder);
364 static DecodeStatus DecodeT2Imm8(MCInst &Inst, unsigned Val,
365                                uint64_t Address, const void *Decoder);
366 static DecodeStatus DecodeT2AddrModeImm8(MCInst &Inst, unsigned Val,
367                                uint64_t Address, const void *Decoder);
368 static DecodeStatus DecodeThumbAddSPImm(MCInst &Inst, uint16_t Val,
369                                uint64_t Address, const void *Decoder);
370 static DecodeStatus DecodeThumbAddSPReg(MCInst &Inst, uint16_t Insn,
371                                 uint64_t Address, const void *Decoder);
372 static DecodeStatus DecodeThumbCPS(MCInst &Inst, uint16_t Insn,
373                                 uint64_t Address, const void *Decoder);
374 static DecodeStatus DecodeQADDInstruction(MCInst &Inst, unsigned Insn,
375                                 uint64_t Address, const void *Decoder);
376 static DecodeStatus DecodeThumbBLXOffset(MCInst &Inst, unsigned Insn,
377                                 uint64_t Address, const void *Decoder);
378 static DecodeStatus DecodeT2AddrModeImm12(MCInst &Inst, unsigned Val,
379                                 uint64_t Address, const void *Decoder);
380 static DecodeStatus DecodeThumbTableBranch(MCInst &Inst, unsigned Val,
381                                 uint64_t Address, const void *Decoder);
382 static DecodeStatus DecodeThumb2BCCInstruction(MCInst &Inst, unsigned Val,
383                                 uint64_t Address, const void *Decoder);
384 static DecodeStatus DecodeT2SOImm(MCInst &Inst, unsigned Val,
385                                 uint64_t Address, const void *Decoder);
386 static DecodeStatus DecodeThumbBCCTargetOperand(MCInst &Inst,unsigned Val,
387                                 uint64_t Address, const void *Decoder);
388 static DecodeStatus DecodeThumbBLTargetOperand(MCInst &Inst, unsigned Val,
389                                 uint64_t Address, const void *Decoder);
390 static DecodeStatus DecodeIT(MCInst &Inst, unsigned Val,
391                                 uint64_t Address, const void *Decoder);
392 static DecodeStatus DecodeT2LDRDPreInstruction(MCInst &Inst,unsigned Insn,
393                                uint64_t Address, const void *Decoder);
394 static DecodeStatus DecodeT2STRDPreInstruction(MCInst &Inst,unsigned Insn,
395                                uint64_t Address, const void *Decoder);
396 static DecodeStatus DecodeT2Adr(MCInst &Inst, unsigned Val,
397                                 uint64_t Address, const void *Decoder);
398 static DecodeStatus DecodeT2LdStPre(MCInst &Inst, unsigned Val,
399                                 uint64_t Address, const void *Decoder);
400 static DecodeStatus DecodeT2ShifterImmOperand(MCInst &Inst, unsigned Val,
401                                 uint64_t Address, const void *Decoder);
402 
403 static DecodeStatus DecodeLDR(MCInst &Inst, unsigned Val,
404                                 uint64_t Address, const void *Decoder);
405 static DecodeStatus DecodeMRRC2(llvm::MCInst &Inst, unsigned Val,
406                                 uint64_t Address, const void *Decoder);
407 #include "ARMGenDisassemblerTables.inc"
408 
409 static MCDisassembler *createARMDisassembler(const Target &T, const MCSubtargetInfo &STI) {
410   return new ARMDisassembler(STI);
411 }
412 
413 static MCDisassembler *createThumbDisassembler(const Target &T, const MCSubtargetInfo &STI) {
414   return new ThumbDisassembler(STI);
415 }
416 
417 DecodeStatus ARMDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
418                                              const MemoryObject &Region,
419                                              uint64_t Address,
420                                              raw_ostream &os,
421                                              raw_ostream &cs) const {
422   CommentStream = &cs;
423 
424   uint8_t bytes[4];
425 
426   assert(!(STI.getFeatureBits() & ARM::ModeThumb) &&
427          "Asked to disassemble an ARM instruction but Subtarget is in Thumb mode!");
428 
429   // We want to read exactly 4 bytes of data.
430   if (Region.readBytes(Address, 4, bytes) == -1) {
431     Size = 0;
432     return MCDisassembler::Fail;
433   }
434 
435   // Encoded as a small-endian 32-bit word in the stream.
436   uint32_t insn = (bytes[3] << 24) |
437                   (bytes[2] << 16) |
438                   (bytes[1] <<  8) |
439                   (bytes[0] <<  0);
440 
441   // Calling the auto-generated decoder function.
442   DecodeStatus result = decodeInstruction(DecoderTableARM32, MI, insn,
443                                           Address, this, STI);
444   if (result != MCDisassembler::Fail) {
445     Size = 4;
446     return result;
447   }
448 
449   // VFP and NEON instructions, similarly, are shared between ARM
450   // and Thumb modes.
451   MI.clear();
452   result = decodeInstruction(DecoderTableVFP32, MI, insn, Address, this, STI);
453   if (result != MCDisassembler::Fail) {
454     Size = 4;
455     return result;
456   }
457 
458   MI.clear();
459   result = decodeInstruction(DecoderTableNEONData32, MI, insn, Address,
460                              this, STI);
461   if (result != MCDisassembler::Fail) {
462     Size = 4;
463     // Add a fake predicate operand, because we share these instruction
464     // definitions with Thumb2 where these instructions are predicable.
465     if (!DecodePredicateOperand(MI, 0xE, Address, this))
466       return MCDisassembler::Fail;
467     return result;
468   }
469 
470   MI.clear();
471   result = decodeInstruction(DecoderTableNEONLoadStore32, MI, insn, Address,
472                              this, STI);
473   if (result != MCDisassembler::Fail) {
474     Size = 4;
475     // Add a fake predicate operand, because we share these instruction
476     // definitions with Thumb2 where these instructions are predicable.
477     if (!DecodePredicateOperand(MI, 0xE, Address, this))
478       return MCDisassembler::Fail;
479     return result;
480   }
481 
482   MI.clear();
483   result = decodeInstruction(DecoderTableNEONDup32, MI, insn, Address,
484                              this, STI);
485   if (result != MCDisassembler::Fail) {
486     Size = 4;
487     // Add a fake predicate operand, because we share these instruction
488     // definitions with Thumb2 where these instructions are predicable.
489     if (!DecodePredicateOperand(MI, 0xE, Address, this))
490       return MCDisassembler::Fail;
491     return result;
492   }
493 
494   MI.clear();
495 
496   Size = 0;
497   return MCDisassembler::Fail;
498 }
499 
500 namespace llvm {
501 extern const MCInstrDesc ARMInsts[];
502 }
503 
504 /// tryAddingSymbolicOperand - trys to add a symbolic operand in place of the
505 /// immediate Value in the MCInst.  The immediate Value has had any PC
506 /// adjustment made by the caller.  If the instruction is a branch instruction
507 /// then isBranch is true, else false.  If the getOpInfo() function was set as
508 /// part of the setupForSymbolicDisassembly() call then that function is called
509 /// to get any symbolic information at the Address for this instruction.  If
510 /// that returns non-zero then the symbolic information it returns is used to
511 /// create an MCExpr and that is added as an operand to the MCInst.  If
512 /// getOpInfo() returns zero and isBranch is true then a symbol look up for
513 /// Value is done and if a symbol is found an MCExpr is created with that, else
514 /// an MCExpr with Value is created.  This function returns true if it adds an
515 /// operand to the MCInst and false otherwise.
516 static bool tryAddingSymbolicOperand(uint64_t Address, int32_t Value,
517                                      bool isBranch, uint64_t InstSize,
518                                      MCInst &MI, const void *Decoder) {
519   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
520   // FIXME: Does it make sense for value to be negative?
521   return Dis->tryAddingSymbolicOperand(MI, (uint32_t)Value, Address, isBranch,
522                                        /* Offset */ 0, InstSize);
523 }
524 
525 /// tryAddingPcLoadReferenceComment - trys to add a comment as to what is being
526 /// referenced by a load instruction with the base register that is the Pc.
527 /// These can often be values in a literal pool near the Address of the
528 /// instruction.  The Address of the instruction and its immediate Value are
529 /// used as a possible literal pool entry.  The SymbolLookUp call back will
530 /// return the name of a symbol referenced by the literal pool's entry if
531 /// the referenced address is that of a symbol.  Or it will return a pointer to
532 /// a literal 'C' string if the referenced address of the literal pool's entry
533 /// is an address into a section with 'C' string literals.
534 static void tryAddingPcLoadReferenceComment(uint64_t Address, int Value,
535                                             const void *Decoder) {
536   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
537   Dis->tryAddingPcLoadReferenceComment(Value, Address);
538 }
539 
540 // Thumb1 instructions don't have explicit S bits.  Rather, they
541 // implicitly set CPSR.  Since it's not represented in the encoding, the
542 // auto-generated decoder won't inject the CPSR operand.  We need to fix
543 // that as a post-pass.
544 static void AddThumb1SBit(MCInst &MI, bool InITBlock) {
545   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
546   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
547   MCInst::iterator I = MI.begin();
548   for (unsigned i = 0; i < NumOps; ++i, ++I) {
549     if (I == MI.end()) break;
550     if (OpInfo[i].isOptionalDef() && OpInfo[i].RegClass == ARM::CCRRegClassID) {
551       if (i > 0 && OpInfo[i-1].isPredicate()) continue;
552       MI.insert(I, MCOperand::CreateReg(InITBlock ? 0 : ARM::CPSR));
553       return;
554     }
555   }
556 
557   MI.insert(I, MCOperand::CreateReg(InITBlock ? 0 : ARM::CPSR));
558 }
559 
560 // Most Thumb instructions don't have explicit predicates in the
561 // encoding, but rather get their predicates from IT context.  We need
562 // to fix up the predicate operands using this context information as a
563 // post-pass.
564 MCDisassembler::DecodeStatus
565 ThumbDisassembler::AddThumbPredicate(MCInst &MI) const {
566   MCDisassembler::DecodeStatus S = Success;
567 
568   // A few instructions actually have predicates encoded in them.  Don't
569   // try to overwrite it if we're seeing one of those.
570   switch (MI.getOpcode()) {
571     case ARM::tBcc:
572     case ARM::t2Bcc:
573     case ARM::tCBZ:
574     case ARM::tCBNZ:
575     case ARM::tCPS:
576     case ARM::t2CPS3p:
577     case ARM::t2CPS2p:
578     case ARM::t2CPS1p:
579     case ARM::tMOVSr:
580     case ARM::tSETEND:
581       // Some instructions (mostly conditional branches) are not
582       // allowed in IT blocks.
583       if (ITBlock.instrInITBlock())
584         S = SoftFail;
585       else
586         return Success;
587       break;
588     case ARM::tB:
589     case ARM::t2B:
590     case ARM::t2TBB:
591     case ARM::t2TBH:
592       // Some instructions (mostly unconditional branches) can
593       // only appears at the end of, or outside of, an IT.
594       if (ITBlock.instrInITBlock() && !ITBlock.instrLastInITBlock())
595         S = SoftFail;
596       break;
597     default:
598       break;
599   }
600 
601   // If we're in an IT block, base the predicate on that.  Otherwise,
602   // assume a predicate of AL.
603   unsigned CC;
604   CC = ITBlock.getITCC();
605   if (CC == 0xF)
606     CC = ARMCC::AL;
607   if (ITBlock.instrInITBlock())
608     ITBlock.advanceITState();
609 
610   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
611   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
612   MCInst::iterator I = MI.begin();
613   for (unsigned i = 0; i < NumOps; ++i, ++I) {
614     if (I == MI.end()) break;
615     if (OpInfo[i].isPredicate()) {
616       I = MI.insert(I, MCOperand::CreateImm(CC));
617       ++I;
618       if (CC == ARMCC::AL)
619         MI.insert(I, MCOperand::CreateReg(0));
620       else
621         MI.insert(I, MCOperand::CreateReg(ARM::CPSR));
622       return S;
623     }
624   }
625 
626   I = MI.insert(I, MCOperand::CreateImm(CC));
627   ++I;
628   if (CC == ARMCC::AL)
629     MI.insert(I, MCOperand::CreateReg(0));
630   else
631     MI.insert(I, MCOperand::CreateReg(ARM::CPSR));
632 
633   return S;
634 }
635 
636 // Thumb VFP instructions are a special case.  Because we share their
637 // encodings between ARM and Thumb modes, and they are predicable in ARM
638 // mode, the auto-generated decoder will give them an (incorrect)
639 // predicate operand.  We need to rewrite these operands based on the IT
640 // context as a post-pass.
641 void ThumbDisassembler::UpdateThumbVFPPredicate(MCInst &MI) const {
642   unsigned CC;
643   CC = ITBlock.getITCC();
644   if (ITBlock.instrInITBlock())
645     ITBlock.advanceITState();
646 
647   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
648   MCInst::iterator I = MI.begin();
649   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
650   for (unsigned i = 0; i < NumOps; ++i, ++I) {
651     if (OpInfo[i].isPredicate() ) {
652       I->setImm(CC);
653       ++I;
654       if (CC == ARMCC::AL)
655         I->setReg(0);
656       else
657         I->setReg(ARM::CPSR);
658       return;
659     }
660   }
661 }
662 
663 DecodeStatus ThumbDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
664                                                const MemoryObject &Region,
665                                                uint64_t Address,
666                                                raw_ostream &os,
667                                                raw_ostream &cs) const {
668   CommentStream = &cs;
669 
670   uint8_t bytes[4];
671 
672   assert((STI.getFeatureBits() & ARM::ModeThumb) &&
673          "Asked to disassemble in Thumb mode but Subtarget is in ARM mode!");
674 
675   // We want to read exactly 2 bytes of data.
676   if (Region.readBytes(Address, 2, bytes) == -1) {
677     Size = 0;
678     return MCDisassembler::Fail;
679   }
680 
681   uint16_t insn16 = (bytes[1] << 8) | bytes[0];
682   DecodeStatus result = decodeInstruction(DecoderTableThumb16, MI, insn16,
683                                           Address, this, STI);
684   if (result != MCDisassembler::Fail) {
685     Size = 2;
686     Check(result, AddThumbPredicate(MI));
687     return result;
688   }
689 
690   MI.clear();
691   result = decodeInstruction(DecoderTableThumbSBit16, MI, insn16,
692                              Address, this, STI);
693   if (result) {
694     Size = 2;
695     bool InITBlock = ITBlock.instrInITBlock();
696     Check(result, AddThumbPredicate(MI));
697     AddThumb1SBit(MI, InITBlock);
698     return result;
699   }
700 
701   MI.clear();
702   result = decodeInstruction(DecoderTableThumb216, MI, insn16,
703                              Address, this, STI);
704   if (result != MCDisassembler::Fail) {
705     Size = 2;
706 
707     // Nested IT blocks are UNPREDICTABLE.  Must be checked before we add
708     // the Thumb predicate.
709     if (MI.getOpcode() == ARM::t2IT && ITBlock.instrInITBlock())
710       result = MCDisassembler::SoftFail;
711 
712     Check(result, AddThumbPredicate(MI));
713 
714     // If we find an IT instruction, we need to parse its condition
715     // code and mask operands so that we can apply them correctly
716     // to the subsequent instructions.
717     if (MI.getOpcode() == ARM::t2IT) {
718 
719       unsigned Firstcond = MI.getOperand(0).getImm();
720       unsigned Mask = MI.getOperand(1).getImm();
721       ITBlock.setITState(Firstcond, Mask);
722     }
723 
724     return result;
725   }
726 
727   // We want to read exactly 4 bytes of data.
728   if (Region.readBytes(Address, 4, bytes) == -1) {
729     Size = 0;
730     return MCDisassembler::Fail;
731   }
732 
733   uint32_t insn32 = (bytes[3] <<  8) |
734                     (bytes[2] <<  0) |
735                     (bytes[1] << 24) |
736                     (bytes[0] << 16);
737   MI.clear();
738   result = decodeInstruction(DecoderTableThumb32, MI, insn32, Address,
739                              this, STI);
740   if (result != MCDisassembler::Fail) {
741     Size = 4;
742     bool InITBlock = ITBlock.instrInITBlock();
743     Check(result, AddThumbPredicate(MI));
744     AddThumb1SBit(MI, InITBlock);
745     return result;
746   }
747 
748   MI.clear();
749   result = decodeInstruction(DecoderTableThumb232, MI, insn32, Address,
750                              this, STI);
751   if (result != MCDisassembler::Fail) {
752     Size = 4;
753     Check(result, AddThumbPredicate(MI));
754     return result;
755   }
756 
757   MI.clear();
758   result = decodeInstruction(DecoderTableVFP32, MI, insn32, Address, this, STI);
759   if (result != MCDisassembler::Fail) {
760     Size = 4;
761     UpdateThumbVFPPredicate(MI);
762     return result;
763   }
764 
765   MI.clear();
766   result = decodeInstruction(DecoderTableNEONDup32, MI, insn32, Address,
767                              this, STI);
768   if (result != MCDisassembler::Fail) {
769     Size = 4;
770     Check(result, AddThumbPredicate(MI));
771     return result;
772   }
773 
774   if (fieldFromInstruction(insn32, 24, 8) == 0xF9) {
775     MI.clear();
776     uint32_t NEONLdStInsn = insn32;
777     NEONLdStInsn &= 0xF0FFFFFF;
778     NEONLdStInsn |= 0x04000000;
779     result = decodeInstruction(DecoderTableNEONLoadStore32, MI, NEONLdStInsn,
780                                Address, this, STI);
781     if (result != MCDisassembler::Fail) {
782       Size = 4;
783       Check(result, AddThumbPredicate(MI));
784       return result;
785     }
786   }
787 
788   if (fieldFromInstruction(insn32, 24, 4) == 0xF) {
789     MI.clear();
790     uint32_t NEONDataInsn = insn32;
791     NEONDataInsn &= 0xF0FFFFFF; // Clear bits 27-24
792     NEONDataInsn |= (NEONDataInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
793     NEONDataInsn |= 0x12000000; // Set bits 28 and 25
794     result = decodeInstruction(DecoderTableNEONData32, MI, NEONDataInsn,
795                                Address, this, STI);
796     if (result != MCDisassembler::Fail) {
797       Size = 4;
798       Check(result, AddThumbPredicate(MI));
799       return result;
800     }
801   }
802 
803   Size = 0;
804   return MCDisassembler::Fail;
805 }
806 
807 
808 extern "C" void LLVMInitializeARMDisassembler() {
809   TargetRegistry::RegisterMCDisassembler(TheARMTarget,
810                                          createARMDisassembler);
811   TargetRegistry::RegisterMCDisassembler(TheThumbTarget,
812                                          createThumbDisassembler);
813 }
814 
815 static const uint16_t GPRDecoderTable[] = {
816   ARM::R0, ARM::R1, ARM::R2, ARM::R3,
817   ARM::R4, ARM::R5, ARM::R6, ARM::R7,
818   ARM::R8, ARM::R9, ARM::R10, ARM::R11,
819   ARM::R12, ARM::SP, ARM::LR, ARM::PC
820 };
821 
822 static DecodeStatus DecodeGPRRegisterClass(MCInst &Inst, unsigned RegNo,
823                                    uint64_t Address, const void *Decoder) {
824   if (RegNo > 15)
825     return MCDisassembler::Fail;
826 
827   unsigned Register = GPRDecoderTable[RegNo];
828   Inst.addOperand(MCOperand::CreateReg(Register));
829   return MCDisassembler::Success;
830 }
831 
832 static DecodeStatus
833 DecodeGPRnopcRegisterClass(MCInst &Inst, unsigned RegNo,
834                            uint64_t Address, const void *Decoder) {
835   DecodeStatus S = MCDisassembler::Success;
836 
837   if (RegNo == 15)
838     S = MCDisassembler::SoftFail;
839 
840   Check(S, DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder));
841 
842   return S;
843 }
844 
845 static DecodeStatus
846 DecodeGPRwithAPSRRegisterClass(MCInst &Inst, unsigned RegNo,
847                                uint64_t Address, const void *Decoder) {
848   DecodeStatus S = MCDisassembler::Success;
849 
850   if (RegNo == 15)
851   {
852     Inst.addOperand(MCOperand::CreateReg(ARM::APSR_NZCV));
853     return MCDisassembler::Success;
854   }
855 
856   Check(S, DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder));
857   return S;
858 }
859 
860 static DecodeStatus DecodetGPRRegisterClass(MCInst &Inst, unsigned RegNo,
861                                    uint64_t Address, const void *Decoder) {
862   if (RegNo > 7)
863     return MCDisassembler::Fail;
864   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
865 }
866 
867 static const uint16_t GPRPairDecoderTable[] = {
868   ARM::R0_R1, ARM::R2_R3,   ARM::R4_R5,  ARM::R6_R7,
869   ARM::R8_R9, ARM::R10_R11, ARM::R12_SP
870 };
871 
872 static DecodeStatus DecodeGPRPairRegisterClass(MCInst &Inst, unsigned RegNo,
873                                    uint64_t Address, const void *Decoder) {
874   DecodeStatus S = MCDisassembler::Success;
875 
876   if (RegNo > 13)
877     return MCDisassembler::Fail;
878 
879   if ((RegNo & 1) || RegNo == 0xe)
880      S = MCDisassembler::SoftFail;
881 
882   unsigned RegisterPair = GPRPairDecoderTable[RegNo/2];
883   Inst.addOperand(MCOperand::CreateReg(RegisterPair));
884   return S;
885 }
886 
887 static DecodeStatus DecodetcGPRRegisterClass(MCInst &Inst, unsigned RegNo,
888                                    uint64_t Address, const void *Decoder) {
889   unsigned Register = 0;
890   switch (RegNo) {
891     case 0:
892       Register = ARM::R0;
893       break;
894     case 1:
895       Register = ARM::R1;
896       break;
897     case 2:
898       Register = ARM::R2;
899       break;
900     case 3:
901       Register = ARM::R3;
902       break;
903     case 9:
904       Register = ARM::R9;
905       break;
906     case 12:
907       Register = ARM::R12;
908       break;
909     default:
910       return MCDisassembler::Fail;
911     }
912 
913   Inst.addOperand(MCOperand::CreateReg(Register));
914   return MCDisassembler::Success;
915 }
916 
917 static DecodeStatus DecoderGPRRegisterClass(MCInst &Inst, unsigned RegNo,
918                                    uint64_t Address, const void *Decoder) {
919   if (RegNo == 13 || RegNo == 15) return MCDisassembler::Fail;
920   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
921 }
922 
923 static const uint16_t SPRDecoderTable[] = {
924      ARM::S0,  ARM::S1,  ARM::S2,  ARM::S3,
925      ARM::S4,  ARM::S5,  ARM::S6,  ARM::S7,
926      ARM::S8,  ARM::S9, ARM::S10, ARM::S11,
927     ARM::S12, ARM::S13, ARM::S14, ARM::S15,
928     ARM::S16, ARM::S17, ARM::S18, ARM::S19,
929     ARM::S20, ARM::S21, ARM::S22, ARM::S23,
930     ARM::S24, ARM::S25, ARM::S26, ARM::S27,
931     ARM::S28, ARM::S29, ARM::S30, ARM::S31
932 };
933 
934 static DecodeStatus DecodeSPRRegisterClass(MCInst &Inst, unsigned RegNo,
935                                    uint64_t Address, const void *Decoder) {
936   if (RegNo > 31)
937     return MCDisassembler::Fail;
938 
939   unsigned Register = SPRDecoderTable[RegNo];
940   Inst.addOperand(MCOperand::CreateReg(Register));
941   return MCDisassembler::Success;
942 }
943 
944 static const uint16_t DPRDecoderTable[] = {
945      ARM::D0,  ARM::D1,  ARM::D2,  ARM::D3,
946      ARM::D4,  ARM::D5,  ARM::D6,  ARM::D7,
947      ARM::D8,  ARM::D9, ARM::D10, ARM::D11,
948     ARM::D12, ARM::D13, ARM::D14, ARM::D15,
949     ARM::D16, ARM::D17, ARM::D18, ARM::D19,
950     ARM::D20, ARM::D21, ARM::D22, ARM::D23,
951     ARM::D24, ARM::D25, ARM::D26, ARM::D27,
952     ARM::D28, ARM::D29, ARM::D30, ARM::D31
953 };
954 
955 static DecodeStatus DecodeDPRRegisterClass(MCInst &Inst, unsigned RegNo,
956                                    uint64_t Address, const void *Decoder) {
957   if (RegNo > 31)
958     return MCDisassembler::Fail;
959 
960   unsigned Register = DPRDecoderTable[RegNo];
961   Inst.addOperand(MCOperand::CreateReg(Register));
962   return MCDisassembler::Success;
963 }
964 
965 static DecodeStatus DecodeDPR_8RegisterClass(MCInst &Inst, unsigned RegNo,
966                                    uint64_t Address, const void *Decoder) {
967   if (RegNo > 7)
968     return MCDisassembler::Fail;
969   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
970 }
971 
972 static DecodeStatus
973 DecodeDPR_VFP2RegisterClass(MCInst &Inst, unsigned RegNo,
974                             uint64_t Address, const void *Decoder) {
975   if (RegNo > 15)
976     return MCDisassembler::Fail;
977   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
978 }
979 
980 static const uint16_t QPRDecoderTable[] = {
981      ARM::Q0,  ARM::Q1,  ARM::Q2,  ARM::Q3,
982      ARM::Q4,  ARM::Q5,  ARM::Q6,  ARM::Q7,
983      ARM::Q8,  ARM::Q9, ARM::Q10, ARM::Q11,
984     ARM::Q12, ARM::Q13, ARM::Q14, ARM::Q15
985 };
986 
987 
988 static DecodeStatus DecodeQPRRegisterClass(MCInst &Inst, unsigned RegNo,
989                                    uint64_t Address, const void *Decoder) {
990   if (RegNo > 31 || (RegNo & 1) != 0)
991     return MCDisassembler::Fail;
992   RegNo >>= 1;
993 
994   unsigned Register = QPRDecoderTable[RegNo];
995   Inst.addOperand(MCOperand::CreateReg(Register));
996   return MCDisassembler::Success;
997 }
998 
999 static const uint16_t DPairDecoderTable[] = {
1000   ARM::Q0,  ARM::D1_D2,   ARM::Q1,  ARM::D3_D4,   ARM::Q2,  ARM::D5_D6,
1001   ARM::Q3,  ARM::D7_D8,   ARM::Q4,  ARM::D9_D10,  ARM::Q5,  ARM::D11_D12,
1002   ARM::Q6,  ARM::D13_D14, ARM::Q7,  ARM::D15_D16, ARM::Q8,  ARM::D17_D18,
1003   ARM::Q9,  ARM::D19_D20, ARM::Q10, ARM::D21_D22, ARM::Q11, ARM::D23_D24,
1004   ARM::Q12, ARM::D25_D26, ARM::Q13, ARM::D27_D28, ARM::Q14, ARM::D29_D30,
1005   ARM::Q15
1006 };
1007 
1008 static DecodeStatus DecodeDPairRegisterClass(MCInst &Inst, unsigned RegNo,
1009                                    uint64_t Address, const void *Decoder) {
1010   if (RegNo > 30)
1011     return MCDisassembler::Fail;
1012 
1013   unsigned Register = DPairDecoderTable[RegNo];
1014   Inst.addOperand(MCOperand::CreateReg(Register));
1015   return MCDisassembler::Success;
1016 }
1017 
1018 static const uint16_t DPairSpacedDecoderTable[] = {
1019   ARM::D0_D2,   ARM::D1_D3,   ARM::D2_D4,   ARM::D3_D5,
1020   ARM::D4_D6,   ARM::D5_D7,   ARM::D6_D8,   ARM::D7_D9,
1021   ARM::D8_D10,  ARM::D9_D11,  ARM::D10_D12, ARM::D11_D13,
1022   ARM::D12_D14, ARM::D13_D15, ARM::D14_D16, ARM::D15_D17,
1023   ARM::D16_D18, ARM::D17_D19, ARM::D18_D20, ARM::D19_D21,
1024   ARM::D20_D22, ARM::D21_D23, ARM::D22_D24, ARM::D23_D25,
1025   ARM::D24_D26, ARM::D25_D27, ARM::D26_D28, ARM::D27_D29,
1026   ARM::D28_D30, ARM::D29_D31
1027 };
1028 
1029 static DecodeStatus DecodeDPairSpacedRegisterClass(MCInst &Inst,
1030                                                    unsigned RegNo,
1031                                                    uint64_t Address,
1032                                                    const void *Decoder) {
1033   if (RegNo > 29)
1034     return MCDisassembler::Fail;
1035 
1036   unsigned Register = DPairSpacedDecoderTable[RegNo];
1037   Inst.addOperand(MCOperand::CreateReg(Register));
1038   return MCDisassembler::Success;
1039 }
1040 
1041 static DecodeStatus DecodePredicateOperand(MCInst &Inst, unsigned Val,
1042                                uint64_t Address, const void *Decoder) {
1043   if (Val == 0xF) return MCDisassembler::Fail;
1044   // AL predicate is not allowed on Thumb1 branches.
1045   if (Inst.getOpcode() == ARM::tBcc && Val == 0xE)
1046     return MCDisassembler::Fail;
1047   Inst.addOperand(MCOperand::CreateImm(Val));
1048   if (Val == ARMCC::AL) {
1049     Inst.addOperand(MCOperand::CreateReg(0));
1050   } else
1051     Inst.addOperand(MCOperand::CreateReg(ARM::CPSR));
1052   return MCDisassembler::Success;
1053 }
1054 
1055 static DecodeStatus DecodeCCOutOperand(MCInst &Inst, unsigned Val,
1056                                uint64_t Address, const void *Decoder) {
1057   if (Val)
1058     Inst.addOperand(MCOperand::CreateReg(ARM::CPSR));
1059   else
1060     Inst.addOperand(MCOperand::CreateReg(0));
1061   return MCDisassembler::Success;
1062 }
1063 
1064 static DecodeStatus DecodeSOImmOperand(MCInst &Inst, unsigned Val,
1065                                uint64_t Address, const void *Decoder) {
1066   uint32_t imm = Val & 0xFF;
1067   uint32_t rot = (Val & 0xF00) >> 7;
1068   uint32_t rot_imm = (imm >> rot) | (imm << ((32-rot) & 0x1F));
1069   Inst.addOperand(MCOperand::CreateImm(rot_imm));
1070   return MCDisassembler::Success;
1071 }
1072 
1073 static DecodeStatus DecodeSORegImmOperand(MCInst &Inst, unsigned Val,
1074                                uint64_t Address, const void *Decoder) {
1075   DecodeStatus S = MCDisassembler::Success;
1076 
1077   unsigned Rm = fieldFromInstruction(Val, 0, 4);
1078   unsigned type = fieldFromInstruction(Val, 5, 2);
1079   unsigned imm = fieldFromInstruction(Val, 7, 5);
1080 
1081   // Register-immediate
1082   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1083     return MCDisassembler::Fail;
1084 
1085   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
1086   switch (type) {
1087     case 0:
1088       Shift = ARM_AM::lsl;
1089       break;
1090     case 1:
1091       Shift = ARM_AM::lsr;
1092       break;
1093     case 2:
1094       Shift = ARM_AM::asr;
1095       break;
1096     case 3:
1097       Shift = ARM_AM::ror;
1098       break;
1099   }
1100 
1101   if (Shift == ARM_AM::ror && imm == 0)
1102     Shift = ARM_AM::rrx;
1103 
1104   unsigned Op = Shift | (imm << 3);
1105   Inst.addOperand(MCOperand::CreateImm(Op));
1106 
1107   return S;
1108 }
1109 
1110 static DecodeStatus DecodeSORegRegOperand(MCInst &Inst, unsigned Val,
1111                                uint64_t Address, const void *Decoder) {
1112   DecodeStatus S = MCDisassembler::Success;
1113 
1114   unsigned Rm = fieldFromInstruction(Val, 0, 4);
1115   unsigned type = fieldFromInstruction(Val, 5, 2);
1116   unsigned Rs = fieldFromInstruction(Val, 8, 4);
1117 
1118   // Register-register
1119   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1120     return MCDisassembler::Fail;
1121   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rs, Address, Decoder)))
1122     return MCDisassembler::Fail;
1123 
1124   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
1125   switch (type) {
1126     case 0:
1127       Shift = ARM_AM::lsl;
1128       break;
1129     case 1:
1130       Shift = ARM_AM::lsr;
1131       break;
1132     case 2:
1133       Shift = ARM_AM::asr;
1134       break;
1135     case 3:
1136       Shift = ARM_AM::ror;
1137       break;
1138   }
1139 
1140   Inst.addOperand(MCOperand::CreateImm(Shift));
1141 
1142   return S;
1143 }
1144 
1145 static DecodeStatus DecodeRegListOperand(MCInst &Inst, unsigned Val,
1146                                  uint64_t Address, const void *Decoder) {
1147   DecodeStatus S = MCDisassembler::Success;
1148 
1149   bool writebackLoad = false;
1150   unsigned writebackReg = 0;
1151   switch (Inst.getOpcode()) {
1152     default:
1153       break;
1154     case ARM::LDMIA_UPD:
1155     case ARM::LDMDB_UPD:
1156     case ARM::LDMIB_UPD:
1157     case ARM::LDMDA_UPD:
1158     case ARM::t2LDMIA_UPD:
1159     case ARM::t2LDMDB_UPD:
1160       writebackLoad = true;
1161       writebackReg = Inst.getOperand(0).getReg();
1162       break;
1163   }
1164 
1165   // Empty register lists are not allowed.
1166   if (Val == 0) return MCDisassembler::Fail;
1167   for (unsigned i = 0; i < 16; ++i) {
1168     if (Val & (1 << i)) {
1169       if (!Check(S, DecodeGPRRegisterClass(Inst, i, Address, Decoder)))
1170         return MCDisassembler::Fail;
1171       // Writeback not allowed if Rn is in the target list.
1172       if (writebackLoad && writebackReg == Inst.end()[-1].getReg())
1173         Check(S, MCDisassembler::SoftFail);
1174     }
1175   }
1176 
1177   return S;
1178 }
1179 
1180 static DecodeStatus DecodeSPRRegListOperand(MCInst &Inst, unsigned Val,
1181                                  uint64_t Address, const void *Decoder) {
1182   DecodeStatus S = MCDisassembler::Success;
1183 
1184   unsigned Vd = fieldFromInstruction(Val, 8, 5);
1185   unsigned regs = fieldFromInstruction(Val, 0, 8);
1186 
1187   // In case of unpredictable encoding, tweak the operands.
1188   if (regs == 0 || (Vd + regs) > 32) {
1189     regs = Vd + regs > 32 ? 32 - Vd : regs;
1190     regs = std::max( 1u, regs);
1191     S = MCDisassembler::SoftFail;
1192   }
1193 
1194   if (!Check(S, DecodeSPRRegisterClass(Inst, Vd, Address, Decoder)))
1195     return MCDisassembler::Fail;
1196   for (unsigned i = 0; i < (regs - 1); ++i) {
1197     if (!Check(S, DecodeSPRRegisterClass(Inst, ++Vd, Address, Decoder)))
1198       return MCDisassembler::Fail;
1199   }
1200 
1201   return S;
1202 }
1203 
1204 static DecodeStatus DecodeDPRRegListOperand(MCInst &Inst, unsigned Val,
1205                                  uint64_t Address, const void *Decoder) {
1206   DecodeStatus S = MCDisassembler::Success;
1207 
1208   unsigned Vd = fieldFromInstruction(Val, 8, 5);
1209   unsigned regs = fieldFromInstruction(Val, 1, 7);
1210 
1211   // In case of unpredictable encoding, tweak the operands.
1212   if (regs == 0 || regs > 16 || (Vd + regs) > 32) {
1213     regs = Vd + regs > 32 ? 32 - Vd : regs;
1214     regs = std::max( 1u, regs);
1215     regs = std::min(16u, regs);
1216     S = MCDisassembler::SoftFail;
1217   }
1218 
1219   if (!Check(S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)))
1220       return MCDisassembler::Fail;
1221   for (unsigned i = 0; i < (regs - 1); ++i) {
1222     if (!Check(S, DecodeDPRRegisterClass(Inst, ++Vd, Address, Decoder)))
1223       return MCDisassembler::Fail;
1224   }
1225 
1226   return S;
1227 }
1228 
1229 static DecodeStatus DecodeBitfieldMaskOperand(MCInst &Inst, unsigned Val,
1230                                       uint64_t Address, const void *Decoder) {
1231   // This operand encodes a mask of contiguous zeros between a specified MSB
1232   // and LSB.  To decode it, we create the mask of all bits MSB-and-lower,
1233   // the mask of all bits LSB-and-lower, and then xor them to create
1234   // the mask of that's all ones on [msb, lsb].  Finally we not it to
1235   // create the final mask.
1236   unsigned msb = fieldFromInstruction(Val, 5, 5);
1237   unsigned lsb = fieldFromInstruction(Val, 0, 5);
1238 
1239   DecodeStatus S = MCDisassembler::Success;
1240   if (lsb > msb) {
1241     Check(S, MCDisassembler::SoftFail);
1242     // The check above will cause the warning for the "potentially undefined
1243     // instruction encoding" but we can't build a bad MCOperand value here
1244     // with a lsb > msb or else printing the MCInst will cause a crash.
1245     lsb = msb;
1246   }
1247 
1248   uint32_t msb_mask = 0xFFFFFFFF;
1249   if (msb != 31) msb_mask = (1U << (msb+1)) - 1;
1250   uint32_t lsb_mask = (1U << lsb) - 1;
1251 
1252   Inst.addOperand(MCOperand::CreateImm(~(msb_mask ^ lsb_mask)));
1253   return S;
1254 }
1255 
1256 static DecodeStatus DecodeCopMemInstruction(MCInst &Inst, unsigned Insn,
1257                                   uint64_t Address, const void *Decoder) {
1258   DecodeStatus S = MCDisassembler::Success;
1259 
1260   unsigned pred = fieldFromInstruction(Insn, 28, 4);
1261   unsigned CRd = fieldFromInstruction(Insn, 12, 4);
1262   unsigned coproc = fieldFromInstruction(Insn, 8, 4);
1263   unsigned imm = fieldFromInstruction(Insn, 0, 8);
1264   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
1265   unsigned U = fieldFromInstruction(Insn, 23, 1);
1266 
1267   switch (Inst.getOpcode()) {
1268     case ARM::LDC_OFFSET:
1269     case ARM::LDC_PRE:
1270     case ARM::LDC_POST:
1271     case ARM::LDC_OPTION:
1272     case ARM::LDCL_OFFSET:
1273     case ARM::LDCL_PRE:
1274     case ARM::LDCL_POST:
1275     case ARM::LDCL_OPTION:
1276     case ARM::STC_OFFSET:
1277     case ARM::STC_PRE:
1278     case ARM::STC_POST:
1279     case ARM::STC_OPTION:
1280     case ARM::STCL_OFFSET:
1281     case ARM::STCL_PRE:
1282     case ARM::STCL_POST:
1283     case ARM::STCL_OPTION:
1284     case ARM::t2LDC_OFFSET:
1285     case ARM::t2LDC_PRE:
1286     case ARM::t2LDC_POST:
1287     case ARM::t2LDC_OPTION:
1288     case ARM::t2LDCL_OFFSET:
1289     case ARM::t2LDCL_PRE:
1290     case ARM::t2LDCL_POST:
1291     case ARM::t2LDCL_OPTION:
1292     case ARM::t2STC_OFFSET:
1293     case ARM::t2STC_PRE:
1294     case ARM::t2STC_POST:
1295     case ARM::t2STC_OPTION:
1296     case ARM::t2STCL_OFFSET:
1297     case ARM::t2STCL_PRE:
1298     case ARM::t2STCL_POST:
1299     case ARM::t2STCL_OPTION:
1300       if (coproc == 0xA || coproc == 0xB)
1301         return MCDisassembler::Fail;
1302       break;
1303     default:
1304       break;
1305   }
1306 
1307   Inst.addOperand(MCOperand::CreateImm(coproc));
1308   Inst.addOperand(MCOperand::CreateImm(CRd));
1309   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1310     return MCDisassembler::Fail;
1311 
1312   switch (Inst.getOpcode()) {
1313     case ARM::t2LDC2_OFFSET:
1314     case ARM::t2LDC2L_OFFSET:
1315     case ARM::t2LDC2_PRE:
1316     case ARM::t2LDC2L_PRE:
1317     case ARM::t2STC2_OFFSET:
1318     case ARM::t2STC2L_OFFSET:
1319     case ARM::t2STC2_PRE:
1320     case ARM::t2STC2L_PRE:
1321     case ARM::LDC2_OFFSET:
1322     case ARM::LDC2L_OFFSET:
1323     case ARM::LDC2_PRE:
1324     case ARM::LDC2L_PRE:
1325     case ARM::STC2_OFFSET:
1326     case ARM::STC2L_OFFSET:
1327     case ARM::STC2_PRE:
1328     case ARM::STC2L_PRE:
1329     case ARM::t2LDC_OFFSET:
1330     case ARM::t2LDCL_OFFSET:
1331     case ARM::t2LDC_PRE:
1332     case ARM::t2LDCL_PRE:
1333     case ARM::t2STC_OFFSET:
1334     case ARM::t2STCL_OFFSET:
1335     case ARM::t2STC_PRE:
1336     case ARM::t2STCL_PRE:
1337     case ARM::LDC_OFFSET:
1338     case ARM::LDCL_OFFSET:
1339     case ARM::LDC_PRE:
1340     case ARM::LDCL_PRE:
1341     case ARM::STC_OFFSET:
1342     case ARM::STCL_OFFSET:
1343     case ARM::STC_PRE:
1344     case ARM::STCL_PRE:
1345       imm = ARM_AM::getAM5Opc(U ? ARM_AM::add : ARM_AM::sub, imm);
1346       Inst.addOperand(MCOperand::CreateImm(imm));
1347       break;
1348     case ARM::t2LDC2_POST:
1349     case ARM::t2LDC2L_POST:
1350     case ARM::t2STC2_POST:
1351     case ARM::t2STC2L_POST:
1352     case ARM::LDC2_POST:
1353     case ARM::LDC2L_POST:
1354     case ARM::STC2_POST:
1355     case ARM::STC2L_POST:
1356     case ARM::t2LDC_POST:
1357     case ARM::t2LDCL_POST:
1358     case ARM::t2STC_POST:
1359     case ARM::t2STCL_POST:
1360     case ARM::LDC_POST:
1361     case ARM::LDCL_POST:
1362     case ARM::STC_POST:
1363     case ARM::STCL_POST:
1364       imm |= U << 8;
1365       // fall through.
1366     default:
1367       // The 'option' variant doesn't encode 'U' in the immediate since
1368       // the immediate is unsigned [0,255].
1369       Inst.addOperand(MCOperand::CreateImm(imm));
1370       break;
1371   }
1372 
1373   switch (Inst.getOpcode()) {
1374     case ARM::LDC_OFFSET:
1375     case ARM::LDC_PRE:
1376     case ARM::LDC_POST:
1377     case ARM::LDC_OPTION:
1378     case ARM::LDCL_OFFSET:
1379     case ARM::LDCL_PRE:
1380     case ARM::LDCL_POST:
1381     case ARM::LDCL_OPTION:
1382     case ARM::STC_OFFSET:
1383     case ARM::STC_PRE:
1384     case ARM::STC_POST:
1385     case ARM::STC_OPTION:
1386     case ARM::STCL_OFFSET:
1387     case ARM::STCL_PRE:
1388     case ARM::STCL_POST:
1389     case ARM::STCL_OPTION:
1390       if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1391         return MCDisassembler::Fail;
1392       break;
1393     default:
1394       break;
1395   }
1396 
1397   return S;
1398 }
1399 
1400 static DecodeStatus
1401 DecodeAddrMode2IdxInstruction(MCInst &Inst, unsigned Insn,
1402                               uint64_t Address, const void *Decoder) {
1403   DecodeStatus S = MCDisassembler::Success;
1404 
1405   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
1406   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
1407   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
1408   unsigned imm = fieldFromInstruction(Insn, 0, 12);
1409   unsigned pred = fieldFromInstruction(Insn, 28, 4);
1410   unsigned reg = fieldFromInstruction(Insn, 25, 1);
1411   unsigned P = fieldFromInstruction(Insn, 24, 1);
1412   unsigned W = fieldFromInstruction(Insn, 21, 1);
1413 
1414   // On stores, the writeback operand precedes Rt.
1415   switch (Inst.getOpcode()) {
1416     case ARM::STR_POST_IMM:
1417     case ARM::STR_POST_REG:
1418     case ARM::STRB_POST_IMM:
1419     case ARM::STRB_POST_REG:
1420     case ARM::STRT_POST_REG:
1421     case ARM::STRT_POST_IMM:
1422     case ARM::STRBT_POST_REG:
1423     case ARM::STRBT_POST_IMM:
1424       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1425         return MCDisassembler::Fail;
1426       break;
1427     default:
1428       break;
1429   }
1430 
1431   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
1432     return MCDisassembler::Fail;
1433 
1434   // On loads, the writeback operand comes after Rt.
1435   switch (Inst.getOpcode()) {
1436     case ARM::LDR_POST_IMM:
1437     case ARM::LDR_POST_REG:
1438     case ARM::LDRB_POST_IMM:
1439     case ARM::LDRB_POST_REG:
1440     case ARM::LDRBT_POST_REG:
1441     case ARM::LDRBT_POST_IMM:
1442     case ARM::LDRT_POST_REG:
1443     case ARM::LDRT_POST_IMM:
1444       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1445         return MCDisassembler::Fail;
1446       break;
1447     default:
1448       break;
1449   }
1450 
1451   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1452     return MCDisassembler::Fail;
1453 
1454   ARM_AM::AddrOpc Op = ARM_AM::add;
1455   if (!fieldFromInstruction(Insn, 23, 1))
1456     Op = ARM_AM::sub;
1457 
1458   bool writeback = (P == 0) || (W == 1);
1459   unsigned idx_mode = 0;
1460   if (P && writeback)
1461     idx_mode = ARMII::IndexModePre;
1462   else if (!P && writeback)
1463     idx_mode = ARMII::IndexModePost;
1464 
1465   if (writeback && (Rn == 15 || Rn == Rt))
1466     S = MCDisassembler::SoftFail; // UNPREDICTABLE
1467 
1468   if (reg) {
1469     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1470       return MCDisassembler::Fail;
1471     ARM_AM::ShiftOpc Opc = ARM_AM::lsl;
1472     switch( fieldFromInstruction(Insn, 5, 2)) {
1473       case 0:
1474         Opc = ARM_AM::lsl;
1475         break;
1476       case 1:
1477         Opc = ARM_AM::lsr;
1478         break;
1479       case 2:
1480         Opc = ARM_AM::asr;
1481         break;
1482       case 3:
1483         Opc = ARM_AM::ror;
1484         break;
1485       default:
1486         return MCDisassembler::Fail;
1487     }
1488     unsigned amt = fieldFromInstruction(Insn, 7, 5);
1489     if (Opc == ARM_AM::ror && amt == 0)
1490       Opc = ARM_AM::rrx;
1491     unsigned imm = ARM_AM::getAM2Opc(Op, amt, Opc, idx_mode);
1492 
1493     Inst.addOperand(MCOperand::CreateImm(imm));
1494   } else {
1495     Inst.addOperand(MCOperand::CreateReg(0));
1496     unsigned tmp = ARM_AM::getAM2Opc(Op, imm, ARM_AM::lsl, idx_mode);
1497     Inst.addOperand(MCOperand::CreateImm(tmp));
1498   }
1499 
1500   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1501     return MCDisassembler::Fail;
1502 
1503   return S;
1504 }
1505 
1506 static DecodeStatus DecodeSORegMemOperand(MCInst &Inst, unsigned Val,
1507                                   uint64_t Address, const void *Decoder) {
1508   DecodeStatus S = MCDisassembler::Success;
1509 
1510   unsigned Rn = fieldFromInstruction(Val, 13, 4);
1511   unsigned Rm = fieldFromInstruction(Val,  0, 4);
1512   unsigned type = fieldFromInstruction(Val, 5, 2);
1513   unsigned imm = fieldFromInstruction(Val, 7, 5);
1514   unsigned U = fieldFromInstruction(Val, 12, 1);
1515 
1516   ARM_AM::ShiftOpc ShOp = ARM_AM::lsl;
1517   switch (type) {
1518     case 0:
1519       ShOp = ARM_AM::lsl;
1520       break;
1521     case 1:
1522       ShOp = ARM_AM::lsr;
1523       break;
1524     case 2:
1525       ShOp = ARM_AM::asr;
1526       break;
1527     case 3:
1528       ShOp = ARM_AM::ror;
1529       break;
1530   }
1531 
1532   if (ShOp == ARM_AM::ror && imm == 0)
1533     ShOp = ARM_AM::rrx;
1534 
1535   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1536     return MCDisassembler::Fail;
1537   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1538     return MCDisassembler::Fail;
1539   unsigned shift;
1540   if (U)
1541     shift = ARM_AM::getAM2Opc(ARM_AM::add, imm, ShOp);
1542   else
1543     shift = ARM_AM::getAM2Opc(ARM_AM::sub, imm, ShOp);
1544   Inst.addOperand(MCOperand::CreateImm(shift));
1545 
1546   return S;
1547 }
1548 
1549 static DecodeStatus
1550 DecodeAddrMode3Instruction(MCInst &Inst, unsigned Insn,
1551                            uint64_t Address, const void *Decoder) {
1552   DecodeStatus S = MCDisassembler::Success;
1553 
1554   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
1555   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
1556   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
1557   unsigned type = fieldFromInstruction(Insn, 22, 1);
1558   unsigned imm = fieldFromInstruction(Insn, 8, 4);
1559   unsigned U = ((~fieldFromInstruction(Insn, 23, 1)) & 1) << 8;
1560   unsigned pred = fieldFromInstruction(Insn, 28, 4);
1561   unsigned W = fieldFromInstruction(Insn, 21, 1);
1562   unsigned P = fieldFromInstruction(Insn, 24, 1);
1563   unsigned Rt2 = Rt + 1;
1564 
1565   bool writeback = (W == 1) | (P == 0);
1566 
1567   // For {LD,ST}RD, Rt must be even, else undefined.
1568   switch (Inst.getOpcode()) {
1569     case ARM::STRD:
1570     case ARM::STRD_PRE:
1571     case ARM::STRD_POST:
1572     case ARM::LDRD:
1573     case ARM::LDRD_PRE:
1574     case ARM::LDRD_POST:
1575       if (Rt & 0x1) S = MCDisassembler::SoftFail;
1576       break;
1577     default:
1578       break;
1579   }
1580   switch (Inst.getOpcode()) {
1581     case ARM::STRD:
1582     case ARM::STRD_PRE:
1583     case ARM::STRD_POST:
1584       if (P == 0 && W == 1)
1585         S = MCDisassembler::SoftFail;
1586 
1587       if (writeback && (Rn == 15 || Rn == Rt || Rn == Rt2))
1588         S = MCDisassembler::SoftFail;
1589       if (type && Rm == 15)
1590         S = MCDisassembler::SoftFail;
1591       if (Rt2 == 15)
1592         S = MCDisassembler::SoftFail;
1593       if (!type && fieldFromInstruction(Insn, 8, 4))
1594         S = MCDisassembler::SoftFail;
1595       break;
1596     case ARM::STRH:
1597     case ARM::STRH_PRE:
1598     case ARM::STRH_POST:
1599       if (Rt == 15)
1600         S = MCDisassembler::SoftFail;
1601       if (writeback && (Rn == 15 || Rn == Rt))
1602         S = MCDisassembler::SoftFail;
1603       if (!type && Rm == 15)
1604         S = MCDisassembler::SoftFail;
1605       break;
1606     case ARM::LDRD:
1607     case ARM::LDRD_PRE:
1608     case ARM::LDRD_POST:
1609       if (type && Rn == 15){
1610         if (Rt2 == 15)
1611           S = MCDisassembler::SoftFail;
1612         break;
1613       }
1614       if (P == 0 && W == 1)
1615         S = MCDisassembler::SoftFail;
1616       if (!type && (Rt2 == 15 || Rm == 15 || Rm == Rt || Rm == Rt2))
1617         S = MCDisassembler::SoftFail;
1618       if (!type && writeback && Rn == 15)
1619         S = MCDisassembler::SoftFail;
1620       if (writeback && (Rn == Rt || Rn == Rt2))
1621         S = MCDisassembler::SoftFail;
1622       break;
1623     case ARM::LDRH:
1624     case ARM::LDRH_PRE:
1625     case ARM::LDRH_POST:
1626       if (type && Rn == 15){
1627         if (Rt == 15)
1628           S = MCDisassembler::SoftFail;
1629         break;
1630       }
1631       if (Rt == 15)
1632         S = MCDisassembler::SoftFail;
1633       if (!type && Rm == 15)
1634         S = MCDisassembler::SoftFail;
1635       if (!type && writeback && (Rn == 15 || Rn == Rt))
1636         S = MCDisassembler::SoftFail;
1637       break;
1638     case ARM::LDRSH:
1639     case ARM::LDRSH_PRE:
1640     case ARM::LDRSH_POST:
1641     case ARM::LDRSB:
1642     case ARM::LDRSB_PRE:
1643     case ARM::LDRSB_POST:
1644       if (type && Rn == 15){
1645         if (Rt == 15)
1646           S = MCDisassembler::SoftFail;
1647         break;
1648       }
1649       if (type && (Rt == 15 || (writeback && Rn == Rt)))
1650         S = MCDisassembler::SoftFail;
1651       if (!type && (Rt == 15 || Rm == 15))
1652         S = MCDisassembler::SoftFail;
1653       if (!type && writeback && (Rn == 15 || Rn == Rt))
1654         S = MCDisassembler::SoftFail;
1655       break;
1656     default:
1657       break;
1658   }
1659 
1660   if (writeback) { // Writeback
1661     if (P)
1662       U |= ARMII::IndexModePre << 9;
1663     else
1664       U |= ARMII::IndexModePost << 9;
1665 
1666     // On stores, the writeback operand precedes Rt.
1667     switch (Inst.getOpcode()) {
1668     case ARM::STRD:
1669     case ARM::STRD_PRE:
1670     case ARM::STRD_POST:
1671     case ARM::STRH:
1672     case ARM::STRH_PRE:
1673     case ARM::STRH_POST:
1674       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1675         return MCDisassembler::Fail;
1676       break;
1677     default:
1678       break;
1679     }
1680   }
1681 
1682   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
1683     return MCDisassembler::Fail;
1684   switch (Inst.getOpcode()) {
1685     case ARM::STRD:
1686     case ARM::STRD_PRE:
1687     case ARM::STRD_POST:
1688     case ARM::LDRD:
1689     case ARM::LDRD_PRE:
1690     case ARM::LDRD_POST:
1691       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
1692         return MCDisassembler::Fail;
1693       break;
1694     default:
1695       break;
1696   }
1697 
1698   if (writeback) {
1699     // On loads, the writeback operand comes after Rt.
1700     switch (Inst.getOpcode()) {
1701     case ARM::LDRD:
1702     case ARM::LDRD_PRE:
1703     case ARM::LDRD_POST:
1704     case ARM::LDRH:
1705     case ARM::LDRH_PRE:
1706     case ARM::LDRH_POST:
1707     case ARM::LDRSH:
1708     case ARM::LDRSH_PRE:
1709     case ARM::LDRSH_POST:
1710     case ARM::LDRSB:
1711     case ARM::LDRSB_PRE:
1712     case ARM::LDRSB_POST:
1713     case ARM::LDRHTr:
1714     case ARM::LDRSBTr:
1715       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1716         return MCDisassembler::Fail;
1717       break;
1718     default:
1719       break;
1720     }
1721   }
1722 
1723   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1724     return MCDisassembler::Fail;
1725 
1726   if (type) {
1727     Inst.addOperand(MCOperand::CreateReg(0));
1728     Inst.addOperand(MCOperand::CreateImm(U | (imm << 4) | Rm));
1729   } else {
1730     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1731     return MCDisassembler::Fail;
1732     Inst.addOperand(MCOperand::CreateImm(U));
1733   }
1734 
1735   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1736     return MCDisassembler::Fail;
1737 
1738   return S;
1739 }
1740 
1741 static DecodeStatus DecodeRFEInstruction(MCInst &Inst, unsigned Insn,
1742                                  uint64_t Address, const void *Decoder) {
1743   DecodeStatus S = MCDisassembler::Success;
1744 
1745   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
1746   unsigned mode = fieldFromInstruction(Insn, 23, 2);
1747 
1748   switch (mode) {
1749     case 0:
1750       mode = ARM_AM::da;
1751       break;
1752     case 1:
1753       mode = ARM_AM::ia;
1754       break;
1755     case 2:
1756       mode = ARM_AM::db;
1757       break;
1758     case 3:
1759       mode = ARM_AM::ib;
1760       break;
1761   }
1762 
1763   Inst.addOperand(MCOperand::CreateImm(mode));
1764   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1765     return MCDisassembler::Fail;
1766 
1767   return S;
1768 }
1769 
1770 static DecodeStatus DecodeQADDInstruction(MCInst &Inst, unsigned Insn,
1771                                uint64_t Address, const void *Decoder) {
1772   DecodeStatus S = MCDisassembler::Success;
1773 
1774   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
1775   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
1776   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
1777   unsigned pred = fieldFromInstruction(Insn, 28, 4);
1778 
1779   if (pred == 0xF)
1780     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
1781 
1782   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
1783     return MCDisassembler::Fail;
1784   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1785     return MCDisassembler::Fail;
1786   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
1787     return MCDisassembler::Fail;
1788   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1789     return MCDisassembler::Fail;
1790   return S;
1791 }
1792 
1793 static DecodeStatus DecodeMemMultipleWritebackInstruction(MCInst &Inst,
1794                                   unsigned Insn,
1795                                   uint64_t Address, const void *Decoder) {
1796   DecodeStatus S = MCDisassembler::Success;
1797 
1798   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
1799   unsigned pred = fieldFromInstruction(Insn, 28, 4);
1800   unsigned reglist = fieldFromInstruction(Insn, 0, 16);
1801 
1802   if (pred == 0xF) {
1803     // Ambiguous with RFE and SRS
1804     switch (Inst.getOpcode()) {
1805       case ARM::LDMDA:
1806         Inst.setOpcode(ARM::RFEDA);
1807         break;
1808       case ARM::LDMDA_UPD:
1809         Inst.setOpcode(ARM::RFEDA_UPD);
1810         break;
1811       case ARM::LDMDB:
1812         Inst.setOpcode(ARM::RFEDB);
1813         break;
1814       case ARM::LDMDB_UPD:
1815         Inst.setOpcode(ARM::RFEDB_UPD);
1816         break;
1817       case ARM::LDMIA:
1818         Inst.setOpcode(ARM::RFEIA);
1819         break;
1820       case ARM::LDMIA_UPD:
1821         Inst.setOpcode(ARM::RFEIA_UPD);
1822         break;
1823       case ARM::LDMIB:
1824         Inst.setOpcode(ARM::RFEIB);
1825         break;
1826       case ARM::LDMIB_UPD:
1827         Inst.setOpcode(ARM::RFEIB_UPD);
1828         break;
1829       case ARM::STMDA:
1830         Inst.setOpcode(ARM::SRSDA);
1831         break;
1832       case ARM::STMDA_UPD:
1833         Inst.setOpcode(ARM::SRSDA_UPD);
1834         break;
1835       case ARM::STMDB:
1836         Inst.setOpcode(ARM::SRSDB);
1837         break;
1838       case ARM::STMDB_UPD:
1839         Inst.setOpcode(ARM::SRSDB_UPD);
1840         break;
1841       case ARM::STMIA:
1842         Inst.setOpcode(ARM::SRSIA);
1843         break;
1844       case ARM::STMIA_UPD:
1845         Inst.setOpcode(ARM::SRSIA_UPD);
1846         break;
1847       case ARM::STMIB:
1848         Inst.setOpcode(ARM::SRSIB);
1849         break;
1850       case ARM::STMIB_UPD:
1851         Inst.setOpcode(ARM::SRSIB_UPD);
1852         break;
1853       default:
1854         return MCDisassembler::Fail;
1855     }
1856 
1857     // For stores (which become SRS's, the only operand is the mode.
1858     if (fieldFromInstruction(Insn, 20, 1) == 0) {
1859       // Check SRS encoding constraints
1860       if (!(fieldFromInstruction(Insn, 22, 1) == 1 &&
1861             fieldFromInstruction(Insn, 20, 1) == 0))
1862         return MCDisassembler::Fail;
1863 
1864       Inst.addOperand(
1865           MCOperand::CreateImm(fieldFromInstruction(Insn, 0, 4)));
1866       return S;
1867     }
1868 
1869     return DecodeRFEInstruction(Inst, Insn, Address, Decoder);
1870   }
1871 
1872   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1873     return MCDisassembler::Fail;
1874   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1875     return MCDisassembler::Fail; // Tied
1876   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1877     return MCDisassembler::Fail;
1878   if (!Check(S, DecodeRegListOperand(Inst, reglist, Address, Decoder)))
1879     return MCDisassembler::Fail;
1880 
1881   return S;
1882 }
1883 
1884 static DecodeStatus DecodeCPSInstruction(MCInst &Inst, unsigned Insn,
1885                                  uint64_t Address, const void *Decoder) {
1886   unsigned imod = fieldFromInstruction(Insn, 18, 2);
1887   unsigned M = fieldFromInstruction(Insn, 17, 1);
1888   unsigned iflags = fieldFromInstruction(Insn, 6, 3);
1889   unsigned mode = fieldFromInstruction(Insn, 0, 5);
1890 
1891   DecodeStatus S = MCDisassembler::Success;
1892 
1893   // This decoder is called from multiple location that do not check
1894   // the full encoding is valid before they do.
1895   if (fieldFromInstruction(Insn, 5, 1) != 0 ||
1896       fieldFromInstruction(Insn, 16, 1) != 0 ||
1897       fieldFromInstruction(Insn, 20, 8) != 0x10)
1898     return MCDisassembler::Fail;
1899 
1900   // imod == '01' --> UNPREDICTABLE
1901   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
1902   // return failure here.  The '01' imod value is unprintable, so there's
1903   // nothing useful we could do even if we returned UNPREDICTABLE.
1904 
1905   if (imod == 1) return MCDisassembler::Fail;
1906 
1907   if (imod && M) {
1908     Inst.setOpcode(ARM::CPS3p);
1909     Inst.addOperand(MCOperand::CreateImm(imod));
1910     Inst.addOperand(MCOperand::CreateImm(iflags));
1911     Inst.addOperand(MCOperand::CreateImm(mode));
1912   } else if (imod && !M) {
1913     Inst.setOpcode(ARM::CPS2p);
1914     Inst.addOperand(MCOperand::CreateImm(imod));
1915     Inst.addOperand(MCOperand::CreateImm(iflags));
1916     if (mode) S = MCDisassembler::SoftFail;
1917   } else if (!imod && M) {
1918     Inst.setOpcode(ARM::CPS1p);
1919     Inst.addOperand(MCOperand::CreateImm(mode));
1920     if (iflags) S = MCDisassembler::SoftFail;
1921   } else {
1922     // imod == '00' && M == '0' --> UNPREDICTABLE
1923     Inst.setOpcode(ARM::CPS1p);
1924     Inst.addOperand(MCOperand::CreateImm(mode));
1925     S = MCDisassembler::SoftFail;
1926   }
1927 
1928   return S;
1929 }
1930 
1931 static DecodeStatus DecodeT2CPSInstruction(MCInst &Inst, unsigned Insn,
1932                                  uint64_t Address, const void *Decoder) {
1933   unsigned imod = fieldFromInstruction(Insn, 9, 2);
1934   unsigned M = fieldFromInstruction(Insn, 8, 1);
1935   unsigned iflags = fieldFromInstruction(Insn, 5, 3);
1936   unsigned mode = fieldFromInstruction(Insn, 0, 5);
1937 
1938   DecodeStatus S = MCDisassembler::Success;
1939 
1940   // imod == '01' --> UNPREDICTABLE
1941   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
1942   // return failure here.  The '01' imod value is unprintable, so there's
1943   // nothing useful we could do even if we returned UNPREDICTABLE.
1944 
1945   if (imod == 1) return MCDisassembler::Fail;
1946 
1947   if (imod && M) {
1948     Inst.setOpcode(ARM::t2CPS3p);
1949     Inst.addOperand(MCOperand::CreateImm(imod));
1950     Inst.addOperand(MCOperand::CreateImm(iflags));
1951     Inst.addOperand(MCOperand::CreateImm(mode));
1952   } else if (imod && !M) {
1953     Inst.setOpcode(ARM::t2CPS2p);
1954     Inst.addOperand(MCOperand::CreateImm(imod));
1955     Inst.addOperand(MCOperand::CreateImm(iflags));
1956     if (mode) S = MCDisassembler::SoftFail;
1957   } else if (!imod && M) {
1958     Inst.setOpcode(ARM::t2CPS1p);
1959     Inst.addOperand(MCOperand::CreateImm(mode));
1960     if (iflags) S = MCDisassembler::SoftFail;
1961   } else {
1962     // imod == '00' && M == '0' --> this is a HINT instruction
1963     int imm = fieldFromInstruction(Insn, 0, 8);
1964     // HINT are defined only for immediate in [0..4]
1965     if(imm > 4) return MCDisassembler::Fail;
1966     Inst.setOpcode(ARM::t2HINT);
1967     Inst.addOperand(MCOperand::CreateImm(imm));
1968   }
1969 
1970   return S;
1971 }
1972 
1973 static DecodeStatus DecodeT2MOVTWInstruction(MCInst &Inst, unsigned Insn,
1974                                  uint64_t Address, const void *Decoder) {
1975   DecodeStatus S = MCDisassembler::Success;
1976 
1977   unsigned Rd = fieldFromInstruction(Insn, 8, 4);
1978   unsigned imm = 0;
1979 
1980   imm |= (fieldFromInstruction(Insn, 0, 8) << 0);
1981   imm |= (fieldFromInstruction(Insn, 12, 3) << 8);
1982   imm |= (fieldFromInstruction(Insn, 16, 4) << 12);
1983   imm |= (fieldFromInstruction(Insn, 26, 1) << 11);
1984 
1985   if (Inst.getOpcode() == ARM::t2MOVTi16)
1986     if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
1987       return MCDisassembler::Fail;
1988   if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
1989     return MCDisassembler::Fail;
1990 
1991   if (!tryAddingSymbolicOperand(Address, imm, false, 4, Inst, Decoder))
1992     Inst.addOperand(MCOperand::CreateImm(imm));
1993 
1994   return S;
1995 }
1996 
1997 static DecodeStatus DecodeArmMOVTWInstruction(MCInst &Inst, unsigned Insn,
1998                                  uint64_t Address, const void *Decoder) {
1999   DecodeStatus S = MCDisassembler::Success;
2000 
2001   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
2002   unsigned pred = fieldFromInstruction(Insn, 28, 4);
2003   unsigned imm = 0;
2004 
2005   imm |= (fieldFromInstruction(Insn, 0, 12) << 0);
2006   imm |= (fieldFromInstruction(Insn, 16, 4) << 12);
2007 
2008   if (Inst.getOpcode() == ARM::MOVTi16)
2009     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
2010       return MCDisassembler::Fail;
2011 
2012   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
2013     return MCDisassembler::Fail;
2014 
2015   if (!tryAddingSymbolicOperand(Address, imm, false, 4, Inst, Decoder))
2016     Inst.addOperand(MCOperand::CreateImm(imm));
2017 
2018   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2019     return MCDisassembler::Fail;
2020 
2021   return S;
2022 }
2023 
2024 static DecodeStatus DecodeSMLAInstruction(MCInst &Inst, unsigned Insn,
2025                                  uint64_t Address, const void *Decoder) {
2026   DecodeStatus S = MCDisassembler::Success;
2027 
2028   unsigned Rd = fieldFromInstruction(Insn, 16, 4);
2029   unsigned Rn = fieldFromInstruction(Insn, 0, 4);
2030   unsigned Rm = fieldFromInstruction(Insn, 8, 4);
2031   unsigned Ra = fieldFromInstruction(Insn, 12, 4);
2032   unsigned pred = fieldFromInstruction(Insn, 28, 4);
2033 
2034   if (pred == 0xF)
2035     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
2036 
2037   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
2038     return MCDisassembler::Fail;
2039   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
2040     return MCDisassembler::Fail;
2041   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
2042     return MCDisassembler::Fail;
2043   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Ra, Address, Decoder)))
2044     return MCDisassembler::Fail;
2045 
2046   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2047     return MCDisassembler::Fail;
2048 
2049   return S;
2050 }
2051 
2052 static DecodeStatus DecodeAddrModeImm12Operand(MCInst &Inst, unsigned Val,
2053                            uint64_t Address, const void *Decoder) {
2054   DecodeStatus S = MCDisassembler::Success;
2055 
2056   unsigned add = fieldFromInstruction(Val, 12, 1);
2057   unsigned imm = fieldFromInstruction(Val, 0, 12);
2058   unsigned Rn = fieldFromInstruction(Val, 13, 4);
2059 
2060   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2061     return MCDisassembler::Fail;
2062 
2063   if (!add) imm *= -1;
2064   if (imm == 0 && !add) imm = INT32_MIN;
2065   Inst.addOperand(MCOperand::CreateImm(imm));
2066   if (Rn == 15)
2067     tryAddingPcLoadReferenceComment(Address, Address + imm + 8, Decoder);
2068 
2069   return S;
2070 }
2071 
2072 static DecodeStatus DecodeAddrMode5Operand(MCInst &Inst, unsigned Val,
2073                                    uint64_t Address, const void *Decoder) {
2074   DecodeStatus S = MCDisassembler::Success;
2075 
2076   unsigned Rn = fieldFromInstruction(Val, 9, 4);
2077   unsigned U = fieldFromInstruction(Val, 8, 1);
2078   unsigned imm = fieldFromInstruction(Val, 0, 8);
2079 
2080   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2081     return MCDisassembler::Fail;
2082 
2083   if (U)
2084     Inst.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(ARM_AM::add, imm)));
2085   else
2086     Inst.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(ARM_AM::sub, imm)));
2087 
2088   return S;
2089 }
2090 
2091 static DecodeStatus DecodeAddrMode7Operand(MCInst &Inst, unsigned Val,
2092                                    uint64_t Address, const void *Decoder) {
2093   return DecodeGPRRegisterClass(Inst, Val, Address, Decoder);
2094 }
2095 
2096 static DecodeStatus
2097 DecodeT2BInstruction(MCInst &Inst, unsigned Insn,
2098                      uint64_t Address, const void *Decoder) {
2099   DecodeStatus Status = MCDisassembler::Success;
2100 
2101   // Note the J1 and J2 values are from the encoded instruction.  So here
2102   // change them to I1 and I2 values via as documented:
2103   // I1 = NOT(J1 EOR S);
2104   // I2 = NOT(J2 EOR S);
2105   // and build the imm32 with one trailing zero as documented:
2106   // imm32 = SignExtend(S:I1:I2:imm10:imm11:'0', 32);
2107   unsigned S = fieldFromInstruction(Insn, 26, 1);
2108   unsigned J1 = fieldFromInstruction(Insn, 13, 1);
2109   unsigned J2 = fieldFromInstruction(Insn, 11, 1);
2110   unsigned I1 = !(J1 ^ S);
2111   unsigned I2 = !(J2 ^ S);
2112   unsigned imm10 = fieldFromInstruction(Insn, 16, 10);
2113   unsigned imm11 = fieldFromInstruction(Insn, 0, 11);
2114   unsigned tmp = (S << 23) | (I1 << 22) | (I2 << 21) | (imm10 << 11) | imm11;
2115   int imm32 = SignExtend32<25>(tmp << 1);
2116   if (!tryAddingSymbolicOperand(Address, Address + imm32 + 4,
2117                                 true, 4, Inst, Decoder))
2118     Inst.addOperand(MCOperand::CreateImm(imm32));
2119 
2120   return Status;
2121 }
2122 
2123 static DecodeStatus
2124 DecodeBranchImmInstruction(MCInst &Inst, unsigned Insn,
2125                            uint64_t Address, const void *Decoder) {
2126   DecodeStatus S = MCDisassembler::Success;
2127 
2128   unsigned pred = fieldFromInstruction(Insn, 28, 4);
2129   unsigned imm = fieldFromInstruction(Insn, 0, 24) << 2;
2130 
2131   if (pred == 0xF) {
2132     Inst.setOpcode(ARM::BLXi);
2133     imm |= fieldFromInstruction(Insn, 24, 1) << 1;
2134     if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<26>(imm) + 8,
2135                                   true, 4, Inst, Decoder))
2136     Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(imm)));
2137     return S;
2138   }
2139 
2140   if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<26>(imm) + 8,
2141                                 true, 4, Inst, Decoder))
2142     Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(imm)));
2143   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2144     return MCDisassembler::Fail;
2145 
2146   return S;
2147 }
2148 
2149 
2150 static DecodeStatus DecodeAddrMode6Operand(MCInst &Inst, unsigned Val,
2151                                    uint64_t Address, const void *Decoder) {
2152   DecodeStatus S = MCDisassembler::Success;
2153 
2154   unsigned Rm = fieldFromInstruction(Val, 0, 4);
2155   unsigned align = fieldFromInstruction(Val, 4, 2);
2156 
2157   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2158     return MCDisassembler::Fail;
2159   if (!align)
2160     Inst.addOperand(MCOperand::CreateImm(0));
2161   else
2162     Inst.addOperand(MCOperand::CreateImm(4 << align));
2163 
2164   return S;
2165 }
2166 
2167 static DecodeStatus DecodeVLDInstruction(MCInst &Inst, unsigned Insn,
2168                                    uint64_t Address, const void *Decoder) {
2169   DecodeStatus S = MCDisassembler::Success;
2170 
2171   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
2172   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
2173   unsigned wb = fieldFromInstruction(Insn, 16, 4);
2174   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
2175   Rn |= fieldFromInstruction(Insn, 4, 2) << 4;
2176   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
2177 
2178   // First output register
2179   switch (Inst.getOpcode()) {
2180   case ARM::VLD1q16: case ARM::VLD1q32: case ARM::VLD1q64: case ARM::VLD1q8:
2181   case ARM::VLD1q16wb_fixed: case ARM::VLD1q16wb_register:
2182   case ARM::VLD1q32wb_fixed: case ARM::VLD1q32wb_register:
2183   case ARM::VLD1q64wb_fixed: case ARM::VLD1q64wb_register:
2184   case ARM::VLD1q8wb_fixed: case ARM::VLD1q8wb_register:
2185   case ARM::VLD2d16: case ARM::VLD2d32: case ARM::VLD2d8:
2186   case ARM::VLD2d16wb_fixed: case ARM::VLD2d16wb_register:
2187   case ARM::VLD2d32wb_fixed: case ARM::VLD2d32wb_register:
2188   case ARM::VLD2d8wb_fixed: case ARM::VLD2d8wb_register:
2189     if (!Check(S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
2190       return MCDisassembler::Fail;
2191     break;
2192   case ARM::VLD2b16:
2193   case ARM::VLD2b32:
2194   case ARM::VLD2b8:
2195   case ARM::VLD2b16wb_fixed:
2196   case ARM::VLD2b16wb_register:
2197   case ARM::VLD2b32wb_fixed:
2198   case ARM::VLD2b32wb_register:
2199   case ARM::VLD2b8wb_fixed:
2200   case ARM::VLD2b8wb_register:
2201     if (!Check(S, DecodeDPairSpacedRegisterClass(Inst, Rd, Address, Decoder)))
2202       return MCDisassembler::Fail;
2203     break;
2204   default:
2205     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2206       return MCDisassembler::Fail;
2207   }
2208 
2209   // Second output register
2210   switch (Inst.getOpcode()) {
2211     case ARM::VLD3d8:
2212     case ARM::VLD3d16:
2213     case ARM::VLD3d32:
2214     case ARM::VLD3d8_UPD:
2215     case ARM::VLD3d16_UPD:
2216     case ARM::VLD3d32_UPD:
2217     case ARM::VLD4d8:
2218     case ARM::VLD4d16:
2219     case ARM::VLD4d32:
2220     case ARM::VLD4d8_UPD:
2221     case ARM::VLD4d16_UPD:
2222     case ARM::VLD4d32_UPD:
2223       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
2224         return MCDisassembler::Fail;
2225       break;
2226     case ARM::VLD3q8:
2227     case ARM::VLD3q16:
2228     case ARM::VLD3q32:
2229     case ARM::VLD3q8_UPD:
2230     case ARM::VLD3q16_UPD:
2231     case ARM::VLD3q32_UPD:
2232     case ARM::VLD4q8:
2233     case ARM::VLD4q16:
2234     case ARM::VLD4q32:
2235     case ARM::VLD4q8_UPD:
2236     case ARM::VLD4q16_UPD:
2237     case ARM::VLD4q32_UPD:
2238       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2239         return MCDisassembler::Fail;
2240     default:
2241       break;
2242   }
2243 
2244   // Third output register
2245   switch(Inst.getOpcode()) {
2246     case ARM::VLD3d8:
2247     case ARM::VLD3d16:
2248     case ARM::VLD3d32:
2249     case ARM::VLD3d8_UPD:
2250     case ARM::VLD3d16_UPD:
2251     case ARM::VLD3d32_UPD:
2252     case ARM::VLD4d8:
2253     case ARM::VLD4d16:
2254     case ARM::VLD4d32:
2255     case ARM::VLD4d8_UPD:
2256     case ARM::VLD4d16_UPD:
2257     case ARM::VLD4d32_UPD:
2258       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2259         return MCDisassembler::Fail;
2260       break;
2261     case ARM::VLD3q8:
2262     case ARM::VLD3q16:
2263     case ARM::VLD3q32:
2264     case ARM::VLD3q8_UPD:
2265     case ARM::VLD3q16_UPD:
2266     case ARM::VLD3q32_UPD:
2267     case ARM::VLD4q8:
2268     case ARM::VLD4q16:
2269     case ARM::VLD4q32:
2270     case ARM::VLD4q8_UPD:
2271     case ARM::VLD4q16_UPD:
2272     case ARM::VLD4q32_UPD:
2273       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
2274         return MCDisassembler::Fail;
2275       break;
2276     default:
2277       break;
2278   }
2279 
2280   // Fourth output register
2281   switch (Inst.getOpcode()) {
2282     case ARM::VLD4d8:
2283     case ARM::VLD4d16:
2284     case ARM::VLD4d32:
2285     case ARM::VLD4d8_UPD:
2286     case ARM::VLD4d16_UPD:
2287     case ARM::VLD4d32_UPD:
2288       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
2289         return MCDisassembler::Fail;
2290       break;
2291     case ARM::VLD4q8:
2292     case ARM::VLD4q16:
2293     case ARM::VLD4q32:
2294     case ARM::VLD4q8_UPD:
2295     case ARM::VLD4q16_UPD:
2296     case ARM::VLD4q32_UPD:
2297       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
2298         return MCDisassembler::Fail;
2299       break;
2300     default:
2301       break;
2302   }
2303 
2304   // Writeback operand
2305   switch (Inst.getOpcode()) {
2306     case ARM::VLD1d8wb_fixed:
2307     case ARM::VLD1d16wb_fixed:
2308     case ARM::VLD1d32wb_fixed:
2309     case ARM::VLD1d64wb_fixed:
2310     case ARM::VLD1d8wb_register:
2311     case ARM::VLD1d16wb_register:
2312     case ARM::VLD1d32wb_register:
2313     case ARM::VLD1d64wb_register:
2314     case ARM::VLD1q8wb_fixed:
2315     case ARM::VLD1q16wb_fixed:
2316     case ARM::VLD1q32wb_fixed:
2317     case ARM::VLD1q64wb_fixed:
2318     case ARM::VLD1q8wb_register:
2319     case ARM::VLD1q16wb_register:
2320     case ARM::VLD1q32wb_register:
2321     case ARM::VLD1q64wb_register:
2322     case ARM::VLD1d8Twb_fixed:
2323     case ARM::VLD1d8Twb_register:
2324     case ARM::VLD1d16Twb_fixed:
2325     case ARM::VLD1d16Twb_register:
2326     case ARM::VLD1d32Twb_fixed:
2327     case ARM::VLD1d32Twb_register:
2328     case ARM::VLD1d64Twb_fixed:
2329     case ARM::VLD1d64Twb_register:
2330     case ARM::VLD1d8Qwb_fixed:
2331     case ARM::VLD1d8Qwb_register:
2332     case ARM::VLD1d16Qwb_fixed:
2333     case ARM::VLD1d16Qwb_register:
2334     case ARM::VLD1d32Qwb_fixed:
2335     case ARM::VLD1d32Qwb_register:
2336     case ARM::VLD1d64Qwb_fixed:
2337     case ARM::VLD1d64Qwb_register:
2338     case ARM::VLD2d8wb_fixed:
2339     case ARM::VLD2d16wb_fixed:
2340     case ARM::VLD2d32wb_fixed:
2341     case ARM::VLD2q8wb_fixed:
2342     case ARM::VLD2q16wb_fixed:
2343     case ARM::VLD2q32wb_fixed:
2344     case ARM::VLD2d8wb_register:
2345     case ARM::VLD2d16wb_register:
2346     case ARM::VLD2d32wb_register:
2347     case ARM::VLD2q8wb_register:
2348     case ARM::VLD2q16wb_register:
2349     case ARM::VLD2q32wb_register:
2350     case ARM::VLD2b8wb_fixed:
2351     case ARM::VLD2b16wb_fixed:
2352     case ARM::VLD2b32wb_fixed:
2353     case ARM::VLD2b8wb_register:
2354     case ARM::VLD2b16wb_register:
2355     case ARM::VLD2b32wb_register:
2356       Inst.addOperand(MCOperand::CreateImm(0));
2357       break;
2358     case ARM::VLD3d8_UPD:
2359     case ARM::VLD3d16_UPD:
2360     case ARM::VLD3d32_UPD:
2361     case ARM::VLD3q8_UPD:
2362     case ARM::VLD3q16_UPD:
2363     case ARM::VLD3q32_UPD:
2364     case ARM::VLD4d8_UPD:
2365     case ARM::VLD4d16_UPD:
2366     case ARM::VLD4d32_UPD:
2367     case ARM::VLD4q8_UPD:
2368     case ARM::VLD4q16_UPD:
2369     case ARM::VLD4q32_UPD:
2370       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
2371         return MCDisassembler::Fail;
2372       break;
2373     default:
2374       break;
2375   }
2376 
2377   // AddrMode6 Base (register+alignment)
2378   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
2379     return MCDisassembler::Fail;
2380 
2381   // AddrMode6 Offset (register)
2382   switch (Inst.getOpcode()) {
2383   default:
2384     // The below have been updated to have explicit am6offset split
2385     // between fixed and register offset. For those instructions not
2386     // yet updated, we need to add an additional reg0 operand for the
2387     // fixed variant.
2388     //
2389     // The fixed offset encodes as Rm == 0xd, so we check for that.
2390     if (Rm == 0xd) {
2391       Inst.addOperand(MCOperand::CreateReg(0));
2392       break;
2393     }
2394     // Fall through to handle the register offset variant.
2395   case ARM::VLD1d8wb_fixed:
2396   case ARM::VLD1d16wb_fixed:
2397   case ARM::VLD1d32wb_fixed:
2398   case ARM::VLD1d64wb_fixed:
2399   case ARM::VLD1d8Twb_fixed:
2400   case ARM::VLD1d16Twb_fixed:
2401   case ARM::VLD1d32Twb_fixed:
2402   case ARM::VLD1d64Twb_fixed:
2403   case ARM::VLD1d8Qwb_fixed:
2404   case ARM::VLD1d16Qwb_fixed:
2405   case ARM::VLD1d32Qwb_fixed:
2406   case ARM::VLD1d64Qwb_fixed:
2407   case ARM::VLD1d8wb_register:
2408   case ARM::VLD1d16wb_register:
2409   case ARM::VLD1d32wb_register:
2410   case ARM::VLD1d64wb_register:
2411   case ARM::VLD1q8wb_fixed:
2412   case ARM::VLD1q16wb_fixed:
2413   case ARM::VLD1q32wb_fixed:
2414   case ARM::VLD1q64wb_fixed:
2415   case ARM::VLD1q8wb_register:
2416   case ARM::VLD1q16wb_register:
2417   case ARM::VLD1q32wb_register:
2418   case ARM::VLD1q64wb_register:
2419     // The fixed offset post-increment encodes Rm == 0xd. The no-writeback
2420     // variant encodes Rm == 0xf. Anything else is a register offset post-
2421     // increment and we need to add the register operand to the instruction.
2422     if (Rm != 0xD && Rm != 0xF &&
2423         !Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2424       return MCDisassembler::Fail;
2425     break;
2426   case ARM::VLD2d8wb_fixed:
2427   case ARM::VLD2d16wb_fixed:
2428   case ARM::VLD2d32wb_fixed:
2429   case ARM::VLD2b8wb_fixed:
2430   case ARM::VLD2b16wb_fixed:
2431   case ARM::VLD2b32wb_fixed:
2432   case ARM::VLD2q8wb_fixed:
2433   case ARM::VLD2q16wb_fixed:
2434   case ARM::VLD2q32wb_fixed:
2435     break;
2436   }
2437 
2438   return S;
2439 }
2440 
2441 static DecodeStatus DecodeVLDST1Instruction(MCInst &Inst, unsigned Insn,
2442                                    uint64_t Address, const void *Decoder) {
2443   unsigned type = fieldFromInstruction(Insn, 8, 4);
2444   unsigned align = fieldFromInstruction(Insn, 4, 2);
2445   if (type == 6 && (align & 2)) return MCDisassembler::Fail;
2446   if (type == 7 && (align & 2)) return MCDisassembler::Fail;
2447   if (type == 10 && align == 3) return MCDisassembler::Fail;
2448 
2449   unsigned load = fieldFromInstruction(Insn, 21, 1);
2450   return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
2451               : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
2452 }
2453 
2454 static DecodeStatus DecodeVLDST2Instruction(MCInst &Inst, unsigned Insn,
2455                                    uint64_t Address, const void *Decoder) {
2456   unsigned size = fieldFromInstruction(Insn, 6, 2);
2457   if (size == 3) return MCDisassembler::Fail;
2458 
2459   unsigned type = fieldFromInstruction(Insn, 8, 4);
2460   unsigned align = fieldFromInstruction(Insn, 4, 2);
2461   if (type == 8 && align == 3) return MCDisassembler::Fail;
2462   if (type == 9 && align == 3) return MCDisassembler::Fail;
2463 
2464   unsigned load = fieldFromInstruction(Insn, 21, 1);
2465   return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
2466               : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
2467 }
2468 
2469 static DecodeStatus DecodeVLDST3Instruction(MCInst &Inst, unsigned Insn,
2470                                    uint64_t Address, const void *Decoder) {
2471   unsigned size = fieldFromInstruction(Insn, 6, 2);
2472   if (size == 3) return MCDisassembler::Fail;
2473 
2474   unsigned align = fieldFromInstruction(Insn, 4, 2);
2475   if (align & 2) return MCDisassembler::Fail;
2476 
2477   unsigned load = fieldFromInstruction(Insn, 21, 1);
2478   return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
2479               : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
2480 }
2481 
2482 static DecodeStatus DecodeVLDST4Instruction(MCInst &Inst, unsigned Insn,
2483                                    uint64_t Address, const void *Decoder) {
2484   unsigned size = fieldFromInstruction(Insn, 6, 2);
2485   if (size == 3) return MCDisassembler::Fail;
2486 
2487   unsigned load = fieldFromInstruction(Insn, 21, 1);
2488   return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
2489               : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
2490 }
2491 
2492 static DecodeStatus DecodeVSTInstruction(MCInst &Inst, unsigned Insn,
2493                                  uint64_t Address, const void *Decoder) {
2494   DecodeStatus S = MCDisassembler::Success;
2495 
2496   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
2497   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
2498   unsigned wb = fieldFromInstruction(Insn, 16, 4);
2499   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
2500   Rn |= fieldFromInstruction(Insn, 4, 2) << 4;
2501   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
2502 
2503   // Writeback Operand
2504   switch (Inst.getOpcode()) {
2505     case ARM::VST1d8wb_fixed:
2506     case ARM::VST1d16wb_fixed:
2507     case ARM::VST1d32wb_fixed:
2508     case ARM::VST1d64wb_fixed:
2509     case ARM::VST1d8wb_register:
2510     case ARM::VST1d16wb_register:
2511     case ARM::VST1d32wb_register:
2512     case ARM::VST1d64wb_register:
2513     case ARM::VST1q8wb_fixed:
2514     case ARM::VST1q16wb_fixed:
2515     case ARM::VST1q32wb_fixed:
2516     case ARM::VST1q64wb_fixed:
2517     case ARM::VST1q8wb_register:
2518     case ARM::VST1q16wb_register:
2519     case ARM::VST1q32wb_register:
2520     case ARM::VST1q64wb_register:
2521     case ARM::VST1d8Twb_fixed:
2522     case ARM::VST1d16Twb_fixed:
2523     case ARM::VST1d32Twb_fixed:
2524     case ARM::VST1d64Twb_fixed:
2525     case ARM::VST1d8Twb_register:
2526     case ARM::VST1d16Twb_register:
2527     case ARM::VST1d32Twb_register:
2528     case ARM::VST1d64Twb_register:
2529     case ARM::VST1d8Qwb_fixed:
2530     case ARM::VST1d16Qwb_fixed:
2531     case ARM::VST1d32Qwb_fixed:
2532     case ARM::VST1d64Qwb_fixed:
2533     case ARM::VST1d8Qwb_register:
2534     case ARM::VST1d16Qwb_register:
2535     case ARM::VST1d32Qwb_register:
2536     case ARM::VST1d64Qwb_register:
2537     case ARM::VST2d8wb_fixed:
2538     case ARM::VST2d16wb_fixed:
2539     case ARM::VST2d32wb_fixed:
2540     case ARM::VST2d8wb_register:
2541     case ARM::VST2d16wb_register:
2542     case ARM::VST2d32wb_register:
2543     case ARM::VST2q8wb_fixed:
2544     case ARM::VST2q16wb_fixed:
2545     case ARM::VST2q32wb_fixed:
2546     case ARM::VST2q8wb_register:
2547     case ARM::VST2q16wb_register:
2548     case ARM::VST2q32wb_register:
2549     case ARM::VST2b8wb_fixed:
2550     case ARM::VST2b16wb_fixed:
2551     case ARM::VST2b32wb_fixed:
2552     case ARM::VST2b8wb_register:
2553     case ARM::VST2b16wb_register:
2554     case ARM::VST2b32wb_register:
2555       if (Rm == 0xF)
2556         return MCDisassembler::Fail;
2557       Inst.addOperand(MCOperand::CreateImm(0));
2558       break;
2559     case ARM::VST3d8_UPD:
2560     case ARM::VST3d16_UPD:
2561     case ARM::VST3d32_UPD:
2562     case ARM::VST3q8_UPD:
2563     case ARM::VST3q16_UPD:
2564     case ARM::VST3q32_UPD:
2565     case ARM::VST4d8_UPD:
2566     case ARM::VST4d16_UPD:
2567     case ARM::VST4d32_UPD:
2568     case ARM::VST4q8_UPD:
2569     case ARM::VST4q16_UPD:
2570     case ARM::VST4q32_UPD:
2571       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
2572         return MCDisassembler::Fail;
2573       break;
2574     default:
2575       break;
2576   }
2577 
2578   // AddrMode6 Base (register+alignment)
2579   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
2580     return MCDisassembler::Fail;
2581 
2582   // AddrMode6 Offset (register)
2583   switch (Inst.getOpcode()) {
2584     default:
2585       if (Rm == 0xD)
2586         Inst.addOperand(MCOperand::CreateReg(0));
2587       else if (Rm != 0xF) {
2588         if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2589           return MCDisassembler::Fail;
2590       }
2591       break;
2592     case ARM::VST1d8wb_fixed:
2593     case ARM::VST1d16wb_fixed:
2594     case ARM::VST1d32wb_fixed:
2595     case ARM::VST1d64wb_fixed:
2596     case ARM::VST1q8wb_fixed:
2597     case ARM::VST1q16wb_fixed:
2598     case ARM::VST1q32wb_fixed:
2599     case ARM::VST1q64wb_fixed:
2600     case ARM::VST1d8Twb_fixed:
2601     case ARM::VST1d16Twb_fixed:
2602     case ARM::VST1d32Twb_fixed:
2603     case ARM::VST1d64Twb_fixed:
2604     case ARM::VST1d8Qwb_fixed:
2605     case ARM::VST1d16Qwb_fixed:
2606     case ARM::VST1d32Qwb_fixed:
2607     case ARM::VST1d64Qwb_fixed:
2608     case ARM::VST2d8wb_fixed:
2609     case ARM::VST2d16wb_fixed:
2610     case ARM::VST2d32wb_fixed:
2611     case ARM::VST2q8wb_fixed:
2612     case ARM::VST2q16wb_fixed:
2613     case ARM::VST2q32wb_fixed:
2614     case ARM::VST2b8wb_fixed:
2615     case ARM::VST2b16wb_fixed:
2616     case ARM::VST2b32wb_fixed:
2617       break;
2618   }
2619 
2620 
2621   // First input register
2622   switch (Inst.getOpcode()) {
2623   case ARM::VST1q16:
2624   case ARM::VST1q32:
2625   case ARM::VST1q64:
2626   case ARM::VST1q8:
2627   case ARM::VST1q16wb_fixed:
2628   case ARM::VST1q16wb_register:
2629   case ARM::VST1q32wb_fixed:
2630   case ARM::VST1q32wb_register:
2631   case ARM::VST1q64wb_fixed:
2632   case ARM::VST1q64wb_register:
2633   case ARM::VST1q8wb_fixed:
2634   case ARM::VST1q8wb_register:
2635   case ARM::VST2d16:
2636   case ARM::VST2d32:
2637   case ARM::VST2d8:
2638   case ARM::VST2d16wb_fixed:
2639   case ARM::VST2d16wb_register:
2640   case ARM::VST2d32wb_fixed:
2641   case ARM::VST2d32wb_register:
2642   case ARM::VST2d8wb_fixed:
2643   case ARM::VST2d8wb_register:
2644     if (!Check(S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
2645       return MCDisassembler::Fail;
2646     break;
2647   case ARM::VST2b16:
2648   case ARM::VST2b32:
2649   case ARM::VST2b8:
2650   case ARM::VST2b16wb_fixed:
2651   case ARM::VST2b16wb_register:
2652   case ARM::VST2b32wb_fixed:
2653   case ARM::VST2b32wb_register:
2654   case ARM::VST2b8wb_fixed:
2655   case ARM::VST2b8wb_register:
2656     if (!Check(S, DecodeDPairSpacedRegisterClass(Inst, Rd, Address, Decoder)))
2657       return MCDisassembler::Fail;
2658     break;
2659   default:
2660     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2661       return MCDisassembler::Fail;
2662   }
2663 
2664   // Second input register
2665   switch (Inst.getOpcode()) {
2666     case ARM::VST3d8:
2667     case ARM::VST3d16:
2668     case ARM::VST3d32:
2669     case ARM::VST3d8_UPD:
2670     case ARM::VST3d16_UPD:
2671     case ARM::VST3d32_UPD:
2672     case ARM::VST4d8:
2673     case ARM::VST4d16:
2674     case ARM::VST4d32:
2675     case ARM::VST4d8_UPD:
2676     case ARM::VST4d16_UPD:
2677     case ARM::VST4d32_UPD:
2678       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
2679         return MCDisassembler::Fail;
2680       break;
2681     case ARM::VST3q8:
2682     case ARM::VST3q16:
2683     case ARM::VST3q32:
2684     case ARM::VST3q8_UPD:
2685     case ARM::VST3q16_UPD:
2686     case ARM::VST3q32_UPD:
2687     case ARM::VST4q8:
2688     case ARM::VST4q16:
2689     case ARM::VST4q32:
2690     case ARM::VST4q8_UPD:
2691     case ARM::VST4q16_UPD:
2692     case ARM::VST4q32_UPD:
2693       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2694         return MCDisassembler::Fail;
2695       break;
2696     default:
2697       break;
2698   }
2699 
2700   // Third input register
2701   switch (Inst.getOpcode()) {
2702     case ARM::VST3d8:
2703     case ARM::VST3d16:
2704     case ARM::VST3d32:
2705     case ARM::VST3d8_UPD:
2706     case ARM::VST3d16_UPD:
2707     case ARM::VST3d32_UPD:
2708     case ARM::VST4d8:
2709     case ARM::VST4d16:
2710     case ARM::VST4d32:
2711     case ARM::VST4d8_UPD:
2712     case ARM::VST4d16_UPD:
2713     case ARM::VST4d32_UPD:
2714       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2715         return MCDisassembler::Fail;
2716       break;
2717     case ARM::VST3q8:
2718     case ARM::VST3q16:
2719     case ARM::VST3q32:
2720     case ARM::VST3q8_UPD:
2721     case ARM::VST3q16_UPD:
2722     case ARM::VST3q32_UPD:
2723     case ARM::VST4q8:
2724     case ARM::VST4q16:
2725     case ARM::VST4q32:
2726     case ARM::VST4q8_UPD:
2727     case ARM::VST4q16_UPD:
2728     case ARM::VST4q32_UPD:
2729       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
2730         return MCDisassembler::Fail;
2731       break;
2732     default:
2733       break;
2734   }
2735 
2736   // Fourth input register
2737   switch (Inst.getOpcode()) {
2738     case ARM::VST4d8:
2739     case ARM::VST4d16:
2740     case ARM::VST4d32:
2741     case ARM::VST4d8_UPD:
2742     case ARM::VST4d16_UPD:
2743     case ARM::VST4d32_UPD:
2744       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
2745         return MCDisassembler::Fail;
2746       break;
2747     case ARM::VST4q8:
2748     case ARM::VST4q16:
2749     case ARM::VST4q32:
2750     case ARM::VST4q8_UPD:
2751     case ARM::VST4q16_UPD:
2752     case ARM::VST4q32_UPD:
2753       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
2754         return MCDisassembler::Fail;
2755       break;
2756     default:
2757       break;
2758   }
2759 
2760   return S;
2761 }
2762 
2763 static DecodeStatus DecodeVLD1DupInstruction(MCInst &Inst, unsigned Insn,
2764                                     uint64_t Address, const void *Decoder) {
2765   DecodeStatus S = MCDisassembler::Success;
2766 
2767   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
2768   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
2769   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
2770   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
2771   unsigned align = fieldFromInstruction(Insn, 4, 1);
2772   unsigned size = fieldFromInstruction(Insn, 6, 2);
2773 
2774   if (size == 0 && align == 1)
2775     return MCDisassembler::Fail;
2776   align *= (1 << size);
2777 
2778   switch (Inst.getOpcode()) {
2779   case ARM::VLD1DUPq16: case ARM::VLD1DUPq32: case ARM::VLD1DUPq8:
2780   case ARM::VLD1DUPq16wb_fixed: case ARM::VLD1DUPq16wb_register:
2781   case ARM::VLD1DUPq32wb_fixed: case ARM::VLD1DUPq32wb_register:
2782   case ARM::VLD1DUPq8wb_fixed: case ARM::VLD1DUPq8wb_register:
2783     if (!Check(S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
2784       return MCDisassembler::Fail;
2785     break;
2786   default:
2787     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2788       return MCDisassembler::Fail;
2789     break;
2790   }
2791   if (Rm != 0xF) {
2792     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2793       return MCDisassembler::Fail;
2794   }
2795 
2796   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2797     return MCDisassembler::Fail;
2798   Inst.addOperand(MCOperand::CreateImm(align));
2799 
2800   // The fixed offset post-increment encodes Rm == 0xd. The no-writeback
2801   // variant encodes Rm == 0xf. Anything else is a register offset post-
2802   // increment and we need to add the register operand to the instruction.
2803   if (Rm != 0xD && Rm != 0xF &&
2804       !Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2805     return MCDisassembler::Fail;
2806 
2807   return S;
2808 }
2809 
2810 static DecodeStatus DecodeVLD2DupInstruction(MCInst &Inst, unsigned Insn,
2811                                     uint64_t Address, const void *Decoder) {
2812   DecodeStatus S = MCDisassembler::Success;
2813 
2814   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
2815   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
2816   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
2817   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
2818   unsigned align = fieldFromInstruction(Insn, 4, 1);
2819   unsigned size = 1 << fieldFromInstruction(Insn, 6, 2);
2820   align *= 2*size;
2821 
2822   switch (Inst.getOpcode()) {
2823   case ARM::VLD2DUPd16: case ARM::VLD2DUPd32: case ARM::VLD2DUPd8:
2824   case ARM::VLD2DUPd16wb_fixed: case ARM::VLD2DUPd16wb_register:
2825   case ARM::VLD2DUPd32wb_fixed: case ARM::VLD2DUPd32wb_register:
2826   case ARM::VLD2DUPd8wb_fixed: case ARM::VLD2DUPd8wb_register:
2827     if (!Check(S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
2828       return MCDisassembler::Fail;
2829     break;
2830   case ARM::VLD2DUPd16x2: case ARM::VLD2DUPd32x2: case ARM::VLD2DUPd8x2:
2831   case ARM::VLD2DUPd16x2wb_fixed: case ARM::VLD2DUPd16x2wb_register:
2832   case ARM::VLD2DUPd32x2wb_fixed: case ARM::VLD2DUPd32x2wb_register:
2833   case ARM::VLD2DUPd8x2wb_fixed: case ARM::VLD2DUPd8x2wb_register:
2834     if (!Check(S, DecodeDPairSpacedRegisterClass(Inst, Rd, Address, Decoder)))
2835       return MCDisassembler::Fail;
2836     break;
2837   default:
2838     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2839       return MCDisassembler::Fail;
2840     break;
2841   }
2842 
2843   if (Rm != 0xF)
2844     Inst.addOperand(MCOperand::CreateImm(0));
2845 
2846   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2847     return MCDisassembler::Fail;
2848   Inst.addOperand(MCOperand::CreateImm(align));
2849 
2850   if (Rm != 0xD && Rm != 0xF) {
2851     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2852       return MCDisassembler::Fail;
2853   }
2854 
2855   return S;
2856 }
2857 
2858 static DecodeStatus DecodeVLD3DupInstruction(MCInst &Inst, unsigned Insn,
2859                                     uint64_t Address, const void *Decoder) {
2860   DecodeStatus S = MCDisassembler::Success;
2861 
2862   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
2863   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
2864   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
2865   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
2866   unsigned inc = fieldFromInstruction(Insn, 5, 1) + 1;
2867 
2868   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2869     return MCDisassembler::Fail;
2870   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
2871     return MCDisassembler::Fail;
2872   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
2873     return MCDisassembler::Fail;
2874   if (Rm != 0xF) {
2875     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2876       return MCDisassembler::Fail;
2877   }
2878 
2879   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2880     return MCDisassembler::Fail;
2881   Inst.addOperand(MCOperand::CreateImm(0));
2882 
2883   if (Rm == 0xD)
2884     Inst.addOperand(MCOperand::CreateReg(0));
2885   else if (Rm != 0xF) {
2886     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2887       return MCDisassembler::Fail;
2888   }
2889 
2890   return S;
2891 }
2892 
2893 static DecodeStatus DecodeVLD4DupInstruction(MCInst &Inst, unsigned Insn,
2894                                     uint64_t Address, const void *Decoder) {
2895   DecodeStatus S = MCDisassembler::Success;
2896 
2897   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
2898   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
2899   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
2900   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
2901   unsigned size = fieldFromInstruction(Insn, 6, 2);
2902   unsigned inc = fieldFromInstruction(Insn, 5, 1) + 1;
2903   unsigned align = fieldFromInstruction(Insn, 4, 1);
2904 
2905   if (size == 0x3) {
2906     if (align == 0)
2907       return MCDisassembler::Fail;
2908     size = 4;
2909     align = 16;
2910   } else {
2911     if (size == 2) {
2912       size = 1 << size;
2913       align *= 8;
2914     } else {
2915       size = 1 << size;
2916       align *= 4*size;
2917     }
2918   }
2919 
2920   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2921     return MCDisassembler::Fail;
2922   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
2923     return MCDisassembler::Fail;
2924   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
2925     return MCDisassembler::Fail;
2926   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3*inc)%32, Address, Decoder)))
2927     return MCDisassembler::Fail;
2928   if (Rm != 0xF) {
2929     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2930       return MCDisassembler::Fail;
2931   }
2932 
2933   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2934     return MCDisassembler::Fail;
2935   Inst.addOperand(MCOperand::CreateImm(align));
2936 
2937   if (Rm == 0xD)
2938     Inst.addOperand(MCOperand::CreateReg(0));
2939   else if (Rm != 0xF) {
2940     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2941       return MCDisassembler::Fail;
2942   }
2943 
2944   return S;
2945 }
2946 
2947 static DecodeStatus
2948 DecodeNEONModImmInstruction(MCInst &Inst, unsigned Insn,
2949                             uint64_t Address, const void *Decoder) {
2950   DecodeStatus S = MCDisassembler::Success;
2951 
2952   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
2953   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
2954   unsigned imm = fieldFromInstruction(Insn, 0, 4);
2955   imm |= fieldFromInstruction(Insn, 16, 3) << 4;
2956   imm |= fieldFromInstruction(Insn, 24, 1) << 7;
2957   imm |= fieldFromInstruction(Insn, 8, 4) << 8;
2958   imm |= fieldFromInstruction(Insn, 5, 1) << 12;
2959   unsigned Q = fieldFromInstruction(Insn, 6, 1);
2960 
2961   if (Q) {
2962     if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2963     return MCDisassembler::Fail;
2964   } else {
2965     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2966     return MCDisassembler::Fail;
2967   }
2968 
2969   Inst.addOperand(MCOperand::CreateImm(imm));
2970 
2971   switch (Inst.getOpcode()) {
2972     case ARM::VORRiv4i16:
2973     case ARM::VORRiv2i32:
2974     case ARM::VBICiv4i16:
2975     case ARM::VBICiv2i32:
2976       if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2977         return MCDisassembler::Fail;
2978       break;
2979     case ARM::VORRiv8i16:
2980     case ARM::VORRiv4i32:
2981     case ARM::VBICiv8i16:
2982     case ARM::VBICiv4i32:
2983       if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2984         return MCDisassembler::Fail;
2985       break;
2986     default:
2987       break;
2988   }
2989 
2990   return S;
2991 }
2992 
2993 static DecodeStatus DecodeVSHLMaxInstruction(MCInst &Inst, unsigned Insn,
2994                                         uint64_t Address, const void *Decoder) {
2995   DecodeStatus S = MCDisassembler::Success;
2996 
2997   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
2998   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
2999   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3000   Rm |= fieldFromInstruction(Insn, 5, 1) << 4;
3001   unsigned size = fieldFromInstruction(Insn, 18, 2);
3002 
3003   if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
3004     return MCDisassembler::Fail;
3005   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
3006     return MCDisassembler::Fail;
3007   Inst.addOperand(MCOperand::CreateImm(8 << size));
3008 
3009   return S;
3010 }
3011 
3012 static DecodeStatus DecodeShiftRight8Imm(MCInst &Inst, unsigned Val,
3013                                uint64_t Address, const void *Decoder) {
3014   Inst.addOperand(MCOperand::CreateImm(8 - Val));
3015   return MCDisassembler::Success;
3016 }
3017 
3018 static DecodeStatus DecodeShiftRight16Imm(MCInst &Inst, unsigned Val,
3019                                uint64_t Address, const void *Decoder) {
3020   Inst.addOperand(MCOperand::CreateImm(16 - Val));
3021   return MCDisassembler::Success;
3022 }
3023 
3024 static DecodeStatus DecodeShiftRight32Imm(MCInst &Inst, unsigned Val,
3025                                uint64_t Address, const void *Decoder) {
3026   Inst.addOperand(MCOperand::CreateImm(32 - Val));
3027   return MCDisassembler::Success;
3028 }
3029 
3030 static DecodeStatus DecodeShiftRight64Imm(MCInst &Inst, unsigned Val,
3031                                uint64_t Address, const void *Decoder) {
3032   Inst.addOperand(MCOperand::CreateImm(64 - Val));
3033   return MCDisassembler::Success;
3034 }
3035 
3036 static DecodeStatus DecodeTBLInstruction(MCInst &Inst, unsigned Insn,
3037                                uint64_t Address, const void *Decoder) {
3038   DecodeStatus S = MCDisassembler::Success;
3039 
3040   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
3041   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
3042   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3043   Rn |= fieldFromInstruction(Insn, 7, 1) << 4;
3044   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3045   Rm |= fieldFromInstruction(Insn, 5, 1) << 4;
3046   unsigned op = fieldFromInstruction(Insn, 6, 1);
3047 
3048   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3049     return MCDisassembler::Fail;
3050   if (op) {
3051     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3052     return MCDisassembler::Fail; // Writeback
3053   }
3054 
3055   switch (Inst.getOpcode()) {
3056   case ARM::VTBL2:
3057   case ARM::VTBX2:
3058     if (!Check(S, DecodeDPairRegisterClass(Inst, Rn, Address, Decoder)))
3059       return MCDisassembler::Fail;
3060     break;
3061   default:
3062     if (!Check(S, DecodeDPRRegisterClass(Inst, Rn, Address, Decoder)))
3063       return MCDisassembler::Fail;
3064   }
3065 
3066   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
3067     return MCDisassembler::Fail;
3068 
3069   return S;
3070 }
3071 
3072 static DecodeStatus DecodeThumbAddSpecialReg(MCInst &Inst, uint16_t Insn,
3073                                      uint64_t Address, const void *Decoder) {
3074   DecodeStatus S = MCDisassembler::Success;
3075 
3076   unsigned dst = fieldFromInstruction(Insn, 8, 3);
3077   unsigned imm = fieldFromInstruction(Insn, 0, 8);
3078 
3079   if (!Check(S, DecodetGPRRegisterClass(Inst, dst, Address, Decoder)))
3080     return MCDisassembler::Fail;
3081 
3082   switch(Inst.getOpcode()) {
3083     default:
3084       return MCDisassembler::Fail;
3085     case ARM::tADR:
3086       break; // tADR does not explicitly represent the PC as an operand.
3087     case ARM::tADDrSPi:
3088       Inst.addOperand(MCOperand::CreateReg(ARM::SP));
3089       break;
3090   }
3091 
3092   Inst.addOperand(MCOperand::CreateImm(imm));
3093   return S;
3094 }
3095 
3096 static DecodeStatus DecodeThumbBROperand(MCInst &Inst, unsigned Val,
3097                                  uint64_t Address, const void *Decoder) {
3098   if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<12>(Val<<1) + 4,
3099                                 true, 2, Inst, Decoder))
3100     Inst.addOperand(MCOperand::CreateImm(SignExtend32<12>(Val << 1)));
3101   return MCDisassembler::Success;
3102 }
3103 
3104 static DecodeStatus DecodeT2BROperand(MCInst &Inst, unsigned Val,
3105                                  uint64_t Address, const void *Decoder) {
3106   if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<21>(Val) + 4,
3107                                 true, 4, Inst, Decoder))
3108     Inst.addOperand(MCOperand::CreateImm(SignExtend32<21>(Val)));
3109   return MCDisassembler::Success;
3110 }
3111 
3112 static DecodeStatus DecodeThumbCmpBROperand(MCInst &Inst, unsigned Val,
3113                                  uint64_t Address, const void *Decoder) {
3114   if (!tryAddingSymbolicOperand(Address, Address + (Val<<1) + 4,
3115                                 true, 2, Inst, Decoder))
3116     Inst.addOperand(MCOperand::CreateImm(Val << 1));
3117   return MCDisassembler::Success;
3118 }
3119 
3120 static DecodeStatus DecodeThumbAddrModeRR(MCInst &Inst, unsigned Val,
3121                                  uint64_t Address, const void *Decoder) {
3122   DecodeStatus S = MCDisassembler::Success;
3123 
3124   unsigned Rn = fieldFromInstruction(Val, 0, 3);
3125   unsigned Rm = fieldFromInstruction(Val, 3, 3);
3126 
3127   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
3128     return MCDisassembler::Fail;
3129   if (!Check(S, DecodetGPRRegisterClass(Inst, Rm, Address, Decoder)))
3130     return MCDisassembler::Fail;
3131 
3132   return S;
3133 }
3134 
3135 static DecodeStatus DecodeThumbAddrModeIS(MCInst &Inst, unsigned Val,
3136                                   uint64_t Address, const void *Decoder) {
3137   DecodeStatus S = MCDisassembler::Success;
3138 
3139   unsigned Rn = fieldFromInstruction(Val, 0, 3);
3140   unsigned imm = fieldFromInstruction(Val, 3, 5);
3141 
3142   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
3143     return MCDisassembler::Fail;
3144   Inst.addOperand(MCOperand::CreateImm(imm));
3145 
3146   return S;
3147 }
3148 
3149 static DecodeStatus DecodeThumbAddrModePC(MCInst &Inst, unsigned Val,
3150                                   uint64_t Address, const void *Decoder) {
3151   unsigned imm = Val << 2;
3152 
3153   Inst.addOperand(MCOperand::CreateImm(imm));
3154   tryAddingPcLoadReferenceComment(Address, (Address & ~2u) + imm + 4, Decoder);
3155 
3156   return MCDisassembler::Success;
3157 }
3158 
3159 static DecodeStatus DecodeThumbAddrModeSP(MCInst &Inst, unsigned Val,
3160                                   uint64_t Address, const void *Decoder) {
3161   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
3162   Inst.addOperand(MCOperand::CreateImm(Val));
3163 
3164   return MCDisassembler::Success;
3165 }
3166 
3167 static DecodeStatus DecodeT2AddrModeSOReg(MCInst &Inst, unsigned Val,
3168                                   uint64_t Address, const void *Decoder) {
3169   DecodeStatus S = MCDisassembler::Success;
3170 
3171   unsigned Rn = fieldFromInstruction(Val, 6, 4);
3172   unsigned Rm = fieldFromInstruction(Val, 2, 4);
3173   unsigned imm = fieldFromInstruction(Val, 0, 2);
3174 
3175   // Thumb stores cannot use PC as dest register.
3176   switch (Inst.getOpcode()) {
3177   case ARM::t2STRHs:
3178   case ARM::t2STRBs:
3179   case ARM::t2STRs:
3180     if (Rn == 15)
3181       return MCDisassembler::Fail;
3182   default:
3183     break;
3184   }
3185 
3186   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3187     return MCDisassembler::Fail;
3188   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
3189     return MCDisassembler::Fail;
3190   Inst.addOperand(MCOperand::CreateImm(imm));
3191 
3192   return S;
3193 }
3194 
3195 static DecodeStatus DecodeT2LoadShift(MCInst &Inst, unsigned Insn,
3196                               uint64_t Address, const void *Decoder) {
3197   DecodeStatus S = MCDisassembler::Success;
3198 
3199   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3200   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3201 
3202   if (Rn == 0xF) {
3203     switch (Inst.getOpcode()) {
3204       case ARM::t2LDRBs:
3205         Inst.setOpcode(ARM::t2LDRBpci);
3206         break;
3207       case ARM::t2LDRHs:
3208         Inst.setOpcode(ARM::t2LDRHpci);
3209         break;
3210       case ARM::t2LDRSHs:
3211         Inst.setOpcode(ARM::t2LDRSHpci);
3212         break;
3213       case ARM::t2LDRSBs:
3214         Inst.setOpcode(ARM::t2LDRSBpci);
3215         break;
3216       case ARM::t2LDRs:
3217         Inst.setOpcode(ARM::t2LDRpci);
3218         break;
3219       case ARM::t2PLDs: {
3220         Inst.setOpcode(ARM::t2PLDi12);
3221         Inst.addOperand(MCOperand::CreateReg(ARM::PC));
3222         int imm = fieldFromInstruction(Insn, 0, 12);
3223         if (!fieldFromInstruction(Insn, 23, 1)) imm *= -1;
3224         Inst.addOperand(MCOperand::CreateImm(imm));
3225         return S;
3226       }
3227       default:
3228         return MCDisassembler::Fail;
3229     }
3230 
3231     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
3232   }
3233 
3234   switch (Inst.getOpcode()) {
3235     case ARM::t2PLDs:
3236     case ARM::t2PLDWs:
3237     case ARM::t2PLIs:
3238       break;
3239     default:
3240       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3241         return MCDisassembler::Fail;
3242   }
3243 
3244   unsigned addrmode = fieldFromInstruction(Insn, 4, 2);
3245   addrmode |= fieldFromInstruction(Insn, 0, 4) << 2;
3246   addrmode |= fieldFromInstruction(Insn, 16, 4) << 6;
3247   if (!Check(S, DecodeT2AddrModeSOReg(Inst, addrmode, Address, Decoder)))
3248     return MCDisassembler::Fail;
3249 
3250   return S;
3251 }
3252 
3253 static DecodeStatus DecodeT2LoadImm8(MCInst &Inst, unsigned Insn,
3254                                 uint64_t Address, const void* Decoder) {
3255   DecodeStatus S = MCDisassembler::Success;
3256 
3257   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3258   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3259   unsigned U = fieldFromInstruction(Insn, 9, 1);
3260   unsigned imm = fieldFromInstruction(Insn, 0, 8);
3261   imm |= (U << 8);
3262   imm |= (Rn << 9);
3263 
3264   if (Rn == 15) {
3265     switch (Inst.getOpcode()) {
3266     case ARM::t2LDRi8:
3267       Inst.setOpcode(ARM::t2LDRpci);
3268       break;
3269     case ARM::t2LDRBi8:
3270       Inst.setOpcode(ARM::t2LDRBpci);
3271       break;
3272     case ARM::t2LDRSBi8:
3273       Inst.setOpcode(ARM::t2LDRSBpci);
3274       break;
3275     case ARM::t2LDRHi8:
3276       Inst.setOpcode(ARM::t2LDRHpci);
3277       break;
3278     case ARM::t2LDRSHi8:
3279       Inst.setOpcode(ARM::t2LDRSHpci);
3280       break;
3281     default:
3282       return MCDisassembler::Fail;
3283     }
3284     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
3285   }
3286 
3287   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3288     return MCDisassembler::Fail;
3289   if (!Check(S, DecodeT2AddrModeImm8(Inst, imm, Address, Decoder)))
3290     return MCDisassembler::Fail;
3291   return S;
3292 }
3293 
3294 static DecodeStatus DecodeT2LoadImm12(MCInst &Inst, unsigned Insn,
3295                                 uint64_t Address, const void* Decoder) {
3296   DecodeStatus S = MCDisassembler::Success;
3297 
3298   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3299   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3300   unsigned imm = fieldFromInstruction(Insn, 0, 12);
3301   imm |= (Rn << 13);
3302 
3303   if (Rn == 15) {
3304     switch (Inst.getOpcode()) {
3305     case ARM::t2LDRi12:
3306       Inst.setOpcode(ARM::t2LDRpci);
3307       break;
3308     case ARM::t2LDRHi12:
3309       Inst.setOpcode(ARM::t2LDRHpci);
3310       break;
3311     case ARM::t2LDRSHi12:
3312       Inst.setOpcode(ARM::t2LDRSHpci);
3313       break;
3314     case ARM::t2LDRBi12:
3315       Inst.setOpcode(ARM::t2LDRBpci);
3316       break;
3317     case ARM::t2LDRSBi12:
3318       Inst.setOpcode(ARM::t2LDRSBpci);
3319       break;
3320     default:
3321       return MCDisassembler::Fail;
3322     }
3323     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
3324   }
3325 
3326   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3327     return MCDisassembler::Fail;
3328   if (!Check(S, DecodeT2AddrModeImm12(Inst, imm, Address, Decoder)))
3329     return MCDisassembler::Fail;
3330   return S;
3331 }
3332 
3333 static DecodeStatus DecodeT2LoadT(MCInst &Inst, unsigned Insn,
3334                                 uint64_t Address, const void* Decoder) {
3335   DecodeStatus S = MCDisassembler::Success;
3336 
3337   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3338   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3339   unsigned imm = fieldFromInstruction(Insn, 0, 8);
3340   imm |= (Rn << 9);
3341 
3342   if (Rn == 15) {
3343     switch (Inst.getOpcode()) {
3344     case ARM::t2LDRT:
3345       Inst.setOpcode(ARM::t2LDRpci);
3346       break;
3347     case ARM::t2LDRBT:
3348       Inst.setOpcode(ARM::t2LDRBpci);
3349       break;
3350     case ARM::t2LDRHT:
3351       Inst.setOpcode(ARM::t2LDRHpci);
3352       break;
3353     case ARM::t2LDRSBT:
3354       Inst.setOpcode(ARM::t2LDRSBpci);
3355       break;
3356     case ARM::t2LDRSHT:
3357       Inst.setOpcode(ARM::t2LDRSHpci);
3358       break;
3359     default:
3360       return MCDisassembler::Fail;
3361     }
3362     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
3363   }
3364 
3365   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
3366     return MCDisassembler::Fail;
3367   if (!Check(S, DecodeT2AddrModeImm8(Inst, imm, Address, Decoder)))
3368     return MCDisassembler::Fail;
3369   return S;
3370 }
3371 
3372 static DecodeStatus DecodeT2LoadLabel(MCInst &Inst, unsigned Insn,
3373                                 uint64_t Address, const void* Decoder) {
3374   DecodeStatus S = MCDisassembler::Success;
3375 
3376   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3377   unsigned U = fieldFromInstruction(Insn, 23, 1);
3378   int imm = fieldFromInstruction(Insn, 0, 12);
3379 
3380   // FIXME: detect and decode PLD properly
3381   if (Inst.getOpcode() == ARM::t2LDRBpci && Rt == 15) {
3382     Inst.setOpcode(ARM::t2PLDi12);
3383     Inst.addOperand(MCOperand::CreateReg(ARM::PC));
3384   } else {
3385     if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3386       return MCDisassembler::Fail;
3387   }
3388 
3389   if (!U) {
3390     // Special case for #-0.
3391     if (imm == 0)
3392       imm = INT32_MIN;
3393     else
3394       imm = -imm;
3395   }
3396   Inst.addOperand(MCOperand::CreateImm(imm));
3397 
3398   return S;
3399 }
3400 
3401 static DecodeStatus DecodeT2Imm8S4(MCInst &Inst, unsigned Val,
3402                            uint64_t Address, const void *Decoder) {
3403   if (Val == 0)
3404     Inst.addOperand(MCOperand::CreateImm(INT32_MIN));
3405   else {
3406     int imm = Val & 0xFF;
3407 
3408     if (!(Val & 0x100)) imm *= -1;
3409     Inst.addOperand(MCOperand::CreateImm(imm * 4));
3410   }
3411 
3412   return MCDisassembler::Success;
3413 }
3414 
3415 static DecodeStatus DecodeT2AddrModeImm8s4(MCInst &Inst, unsigned Val,
3416                                    uint64_t Address, const void *Decoder) {
3417   DecodeStatus S = MCDisassembler::Success;
3418 
3419   unsigned Rn = fieldFromInstruction(Val, 9, 4);
3420   unsigned imm = fieldFromInstruction(Val, 0, 9);
3421 
3422   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3423     return MCDisassembler::Fail;
3424   if (!Check(S, DecodeT2Imm8S4(Inst, imm, Address, Decoder)))
3425     return MCDisassembler::Fail;
3426 
3427   return S;
3428 }
3429 
3430 static DecodeStatus DecodeT2AddrModeImm0_1020s4(MCInst &Inst,unsigned Val,
3431                                    uint64_t Address, const void *Decoder) {
3432   DecodeStatus S = MCDisassembler::Success;
3433 
3434   unsigned Rn = fieldFromInstruction(Val, 8, 4);
3435   unsigned imm = fieldFromInstruction(Val, 0, 8);
3436 
3437   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
3438     return MCDisassembler::Fail;
3439 
3440   Inst.addOperand(MCOperand::CreateImm(imm));
3441 
3442   return S;
3443 }
3444 
3445 static DecodeStatus DecodeT2Imm8(MCInst &Inst, unsigned Val,
3446                          uint64_t Address, const void *Decoder) {
3447   int imm = Val & 0xFF;
3448   if (Val == 0)
3449     imm = INT32_MIN;
3450   else if (!(Val & 0x100))
3451     imm *= -1;
3452   Inst.addOperand(MCOperand::CreateImm(imm));
3453 
3454   return MCDisassembler::Success;
3455 }
3456 
3457 
3458 static DecodeStatus DecodeT2AddrModeImm8(MCInst &Inst, unsigned Val,
3459                                  uint64_t Address, const void *Decoder) {
3460   DecodeStatus S = MCDisassembler::Success;
3461 
3462   unsigned Rn = fieldFromInstruction(Val, 9, 4);
3463   unsigned imm = fieldFromInstruction(Val, 0, 9);
3464 
3465   // Thumb stores cannot use PC as dest register.
3466   switch (Inst.getOpcode()) {
3467   case ARM::t2STRT:
3468   case ARM::t2STRBT:
3469   case ARM::t2STRHT:
3470   case ARM::t2STRi8:
3471   case ARM::t2STRHi8:
3472   case ARM::t2STRBi8:
3473     if (Rn == 15)
3474       return MCDisassembler::Fail;
3475     break;
3476   default:
3477     break;
3478   }
3479 
3480   // Some instructions always use an additive offset.
3481   switch (Inst.getOpcode()) {
3482     case ARM::t2LDRT:
3483     case ARM::t2LDRBT:
3484     case ARM::t2LDRHT:
3485     case ARM::t2LDRSBT:
3486     case ARM::t2LDRSHT:
3487     case ARM::t2STRT:
3488     case ARM::t2STRBT:
3489     case ARM::t2STRHT:
3490       imm |= 0x100;
3491       break;
3492     default:
3493       break;
3494   }
3495 
3496   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3497     return MCDisassembler::Fail;
3498   if (!Check(S, DecodeT2Imm8(Inst, imm, Address, Decoder)))
3499     return MCDisassembler::Fail;
3500 
3501   return S;
3502 }
3503 
3504 static DecodeStatus DecodeT2LdStPre(MCInst &Inst, unsigned Insn,
3505                                     uint64_t Address, const void *Decoder) {
3506   DecodeStatus S = MCDisassembler::Success;
3507 
3508   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3509   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3510   unsigned addr = fieldFromInstruction(Insn, 0, 8);
3511   addr |= fieldFromInstruction(Insn, 9, 1) << 8;
3512   addr |= Rn << 9;
3513   unsigned load = fieldFromInstruction(Insn, 20, 1);
3514 
3515   if (Rn == 15) {
3516     switch (Inst.getOpcode()) {
3517     case ARM::t2LDR_PRE:
3518     case ARM::t2LDR_POST:
3519       Inst.setOpcode(ARM::t2LDRpci);
3520       break;
3521     case ARM::t2LDRB_PRE:
3522     case ARM::t2LDRB_POST:
3523       Inst.setOpcode(ARM::t2LDRBpci);
3524       break;
3525     case ARM::t2LDRH_PRE:
3526     case ARM::t2LDRH_POST:
3527       Inst.setOpcode(ARM::t2LDRHpci);
3528       break;
3529     case ARM::t2LDRSB_PRE:
3530     case ARM::t2LDRSB_POST:
3531       Inst.setOpcode(ARM::t2LDRSBpci);
3532       break;
3533     case ARM::t2LDRSH_PRE:
3534     case ARM::t2LDRSH_POST:
3535       Inst.setOpcode(ARM::t2LDRSHpci);
3536       break;
3537     default:
3538       return MCDisassembler::Fail;
3539     }
3540     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
3541   }
3542 
3543   if (!load) {
3544     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3545       return MCDisassembler::Fail;
3546   }
3547 
3548   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3549     return MCDisassembler::Fail;
3550 
3551   if (load) {
3552     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3553       return MCDisassembler::Fail;
3554   }
3555 
3556   if (!Check(S, DecodeT2AddrModeImm8(Inst, addr, Address, Decoder)))
3557     return MCDisassembler::Fail;
3558 
3559   return S;
3560 }
3561 
3562 static DecodeStatus DecodeT2AddrModeImm12(MCInst &Inst, unsigned Val,
3563                                   uint64_t Address, const void *Decoder) {
3564   DecodeStatus S = MCDisassembler::Success;
3565 
3566   unsigned Rn = fieldFromInstruction(Val, 13, 4);
3567   unsigned imm = fieldFromInstruction(Val, 0, 12);
3568 
3569   // Thumb stores cannot use PC as dest register.
3570   switch (Inst.getOpcode()) {
3571   case ARM::t2STRi12:
3572   case ARM::t2STRBi12:
3573   case ARM::t2STRHi12:
3574     if (Rn == 15)
3575       return MCDisassembler::Fail;
3576   default:
3577     break;
3578   }
3579 
3580   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3581     return MCDisassembler::Fail;
3582   Inst.addOperand(MCOperand::CreateImm(imm));
3583 
3584   return S;
3585 }
3586 
3587 
3588 static DecodeStatus DecodeThumbAddSPImm(MCInst &Inst, uint16_t Insn,
3589                                 uint64_t Address, const void *Decoder) {
3590   unsigned imm = fieldFromInstruction(Insn, 0, 7);
3591 
3592   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
3593   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
3594   Inst.addOperand(MCOperand::CreateImm(imm));
3595 
3596   return MCDisassembler::Success;
3597 }
3598 
3599 static DecodeStatus DecodeThumbAddSPReg(MCInst &Inst, uint16_t Insn,
3600                                 uint64_t Address, const void *Decoder) {
3601   DecodeStatus S = MCDisassembler::Success;
3602 
3603   if (Inst.getOpcode() == ARM::tADDrSP) {
3604     unsigned Rdm = fieldFromInstruction(Insn, 0, 3);
3605     Rdm |= fieldFromInstruction(Insn, 7, 1) << 3;
3606 
3607     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
3608     return MCDisassembler::Fail;
3609     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
3610     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
3611     return MCDisassembler::Fail;
3612   } else if (Inst.getOpcode() == ARM::tADDspr) {
3613     unsigned Rm = fieldFromInstruction(Insn, 3, 4);
3614 
3615     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
3616     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
3617     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3618     return MCDisassembler::Fail;
3619   }
3620 
3621   return S;
3622 }
3623 
3624 static DecodeStatus DecodeThumbCPS(MCInst &Inst, uint16_t Insn,
3625                            uint64_t Address, const void *Decoder) {
3626   unsigned imod = fieldFromInstruction(Insn, 4, 1) | 0x2;
3627   unsigned flags = fieldFromInstruction(Insn, 0, 3);
3628 
3629   Inst.addOperand(MCOperand::CreateImm(imod));
3630   Inst.addOperand(MCOperand::CreateImm(flags));
3631 
3632   return MCDisassembler::Success;
3633 }
3634 
3635 static DecodeStatus DecodePostIdxReg(MCInst &Inst, unsigned Insn,
3636                              uint64_t Address, const void *Decoder) {
3637   DecodeStatus S = MCDisassembler::Success;
3638   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3639   unsigned add = fieldFromInstruction(Insn, 4, 1);
3640 
3641   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
3642     return MCDisassembler::Fail;
3643   Inst.addOperand(MCOperand::CreateImm(add));
3644 
3645   return S;
3646 }
3647 
3648 static DecodeStatus DecodeThumbBLXOffset(MCInst &Inst, unsigned Val,
3649                                  uint64_t Address, const void *Decoder) {
3650   // Val is passed in as S:J1:J2:imm10H:imm10L:'0'
3651   // Note only one trailing zero not two.  Also the J1 and J2 values are from
3652   // the encoded instruction.  So here change to I1 and I2 values via:
3653   // I1 = NOT(J1 EOR S);
3654   // I2 = NOT(J2 EOR S);
3655   // and build the imm32 with two trailing zeros as documented:
3656   // imm32 = SignExtend(S:I1:I2:imm10H:imm10L:'00', 32);
3657   unsigned S = (Val >> 23) & 1;
3658   unsigned J1 = (Val >> 22) & 1;
3659   unsigned J2 = (Val >> 21) & 1;
3660   unsigned I1 = !(J1 ^ S);
3661   unsigned I2 = !(J2 ^ S);
3662   unsigned tmp = (Val & ~0x600000) | (I1 << 22) | (I2 << 21);
3663   int imm32 = SignExtend32<25>(tmp << 1);
3664 
3665   if (!tryAddingSymbolicOperand(Address,
3666                                 (Address & ~2u) + imm32 + 4,
3667                                 true, 4, Inst, Decoder))
3668     Inst.addOperand(MCOperand::CreateImm(imm32));
3669   return MCDisassembler::Success;
3670 }
3671 
3672 static DecodeStatus DecodeCoprocessor(MCInst &Inst, unsigned Val,
3673                               uint64_t Address, const void *Decoder) {
3674   if (Val == 0xA || Val == 0xB)
3675     return MCDisassembler::Fail;
3676 
3677   Inst.addOperand(MCOperand::CreateImm(Val));
3678   return MCDisassembler::Success;
3679 }
3680 
3681 static DecodeStatus
3682 DecodeThumbTableBranch(MCInst &Inst, unsigned Insn,
3683                        uint64_t Address, const void *Decoder) {
3684   DecodeStatus S = MCDisassembler::Success;
3685 
3686   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3687   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3688 
3689   if (Rn == ARM::SP) S = MCDisassembler::SoftFail;
3690   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3691     return MCDisassembler::Fail;
3692   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
3693     return MCDisassembler::Fail;
3694   return S;
3695 }
3696 
3697 static DecodeStatus
3698 DecodeThumb2BCCInstruction(MCInst &Inst, unsigned Insn,
3699                            uint64_t Address, const void *Decoder) {
3700   DecodeStatus S = MCDisassembler::Success;
3701 
3702   unsigned pred = fieldFromInstruction(Insn, 22, 4);
3703   if (pred == 0xE || pred == 0xF) {
3704     unsigned opc = fieldFromInstruction(Insn, 4, 28);
3705     switch (opc) {
3706       default:
3707         return MCDisassembler::Fail;
3708       case 0xf3bf8f4:
3709         Inst.setOpcode(ARM::t2DSB);
3710         break;
3711       case 0xf3bf8f5:
3712         Inst.setOpcode(ARM::t2DMB);
3713         break;
3714       case 0xf3bf8f6:
3715         Inst.setOpcode(ARM::t2ISB);
3716         break;
3717     }
3718 
3719     unsigned imm = fieldFromInstruction(Insn, 0, 4);
3720     return DecodeMemBarrierOption(Inst, imm, Address, Decoder);
3721   }
3722 
3723   unsigned brtarget = fieldFromInstruction(Insn, 0, 11) << 1;
3724   brtarget |= fieldFromInstruction(Insn, 11, 1) << 19;
3725   brtarget |= fieldFromInstruction(Insn, 13, 1) << 18;
3726   brtarget |= fieldFromInstruction(Insn, 16, 6) << 12;
3727   brtarget |= fieldFromInstruction(Insn, 26, 1) << 20;
3728 
3729   if (!Check(S, DecodeT2BROperand(Inst, brtarget, Address, Decoder)))
3730     return MCDisassembler::Fail;
3731   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3732     return MCDisassembler::Fail;
3733 
3734   return S;
3735 }
3736 
3737 // Decode a shifted immediate operand.  These basically consist
3738 // of an 8-bit value, and a 4-bit directive that specifies either
3739 // a splat operation or a rotation.
3740 static DecodeStatus DecodeT2SOImm(MCInst &Inst, unsigned Val,
3741                           uint64_t Address, const void *Decoder) {
3742   unsigned ctrl = fieldFromInstruction(Val, 10, 2);
3743   if (ctrl == 0) {
3744     unsigned byte = fieldFromInstruction(Val, 8, 2);
3745     unsigned imm = fieldFromInstruction(Val, 0, 8);
3746     switch (byte) {
3747       case 0:
3748         Inst.addOperand(MCOperand::CreateImm(imm));
3749         break;
3750       case 1:
3751         Inst.addOperand(MCOperand::CreateImm((imm << 16) | imm));
3752         break;
3753       case 2:
3754         Inst.addOperand(MCOperand::CreateImm((imm << 24) | (imm << 8)));
3755         break;
3756       case 3:
3757         Inst.addOperand(MCOperand::CreateImm((imm << 24) | (imm << 16) |
3758                                              (imm << 8)  |  imm));
3759         break;
3760     }
3761   } else {
3762     unsigned unrot = fieldFromInstruction(Val, 0, 7) | 0x80;
3763     unsigned rot = fieldFromInstruction(Val, 7, 5);
3764     unsigned imm = (unrot >> rot) | (unrot << ((32-rot)&31));
3765     Inst.addOperand(MCOperand::CreateImm(imm));
3766   }
3767 
3768   return MCDisassembler::Success;
3769 }
3770 
3771 static DecodeStatus
3772 DecodeThumbBCCTargetOperand(MCInst &Inst, unsigned Val,
3773                             uint64_t Address, const void *Decoder){
3774   if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<9>(Val<<1) + 4,
3775                                 true, 2, Inst, Decoder))
3776     Inst.addOperand(MCOperand::CreateImm(SignExtend32<9>(Val << 1)));
3777   return MCDisassembler::Success;
3778 }
3779 
3780 static DecodeStatus DecodeThumbBLTargetOperand(MCInst &Inst, unsigned Val,
3781                                        uint64_t Address, const void *Decoder){
3782   // Val is passed in as S:J1:J2:imm10:imm11
3783   // Note no trailing zero after imm11.  Also the J1 and J2 values are from
3784   // the encoded instruction.  So here change to I1 and I2 values via:
3785   // I1 = NOT(J1 EOR S);
3786   // I2 = NOT(J2 EOR S);
3787   // and build the imm32 with one trailing zero as documented:
3788   // imm32 = SignExtend(S:I1:I2:imm10:imm11:'0', 32);
3789   unsigned S = (Val >> 23) & 1;
3790   unsigned J1 = (Val >> 22) & 1;
3791   unsigned J2 = (Val >> 21) & 1;
3792   unsigned I1 = !(J1 ^ S);
3793   unsigned I2 = !(J2 ^ S);
3794   unsigned tmp = (Val & ~0x600000) | (I1 << 22) | (I2 << 21);
3795   int imm32 = SignExtend32<25>(tmp << 1);
3796 
3797   if (!tryAddingSymbolicOperand(Address, Address + imm32 + 4,
3798                                 true, 4, Inst, Decoder))
3799     Inst.addOperand(MCOperand::CreateImm(imm32));
3800   return MCDisassembler::Success;
3801 }
3802 
3803 static DecodeStatus DecodeMemBarrierOption(MCInst &Inst, unsigned Val,
3804                                    uint64_t Address, const void *Decoder) {
3805   if (Val & ~0xf)
3806     return MCDisassembler::Fail;
3807 
3808   Inst.addOperand(MCOperand::CreateImm(Val));
3809   return MCDisassembler::Success;
3810 }
3811 
3812 static DecodeStatus DecodeInstSyncBarrierOption(MCInst &Inst, unsigned Val,
3813                                         uint64_t Address, const void *Decoder) {
3814   if (Val & ~0xf)
3815     return MCDisassembler::Fail;
3816 
3817   Inst.addOperand(MCOperand::CreateImm(Val));
3818   return MCDisassembler::Success;
3819 }
3820 
3821 static DecodeStatus DecodeMSRMask(MCInst &Inst, unsigned Val,
3822                           uint64_t Address, const void *Decoder) {
3823   if (!Val) return MCDisassembler::Fail;
3824   Inst.addOperand(MCOperand::CreateImm(Val));
3825   return MCDisassembler::Success;
3826 }
3827 
3828 static DecodeStatus DecodeDoubleRegLoad(MCInst &Inst, unsigned Insn,
3829                                         uint64_t Address, const void *Decoder) {
3830   DecodeStatus S = MCDisassembler::Success;
3831 
3832   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3833   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3834   unsigned pred = fieldFromInstruction(Insn, 28, 4);
3835 
3836   if (Rn == 0xF)
3837     S = MCDisassembler::SoftFail;
3838 
3839   if (!Check(S, DecodeGPRPairRegisterClass(Inst, Rt, Address, Decoder)))
3840     return MCDisassembler::Fail;
3841   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3842     return MCDisassembler::Fail;
3843   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3844     return MCDisassembler::Fail;
3845 
3846   return S;
3847 }
3848 
3849 static DecodeStatus DecodeDoubleRegStore(MCInst &Inst, unsigned Insn,
3850                                          uint64_t Address, const void *Decoder){
3851   DecodeStatus S = MCDisassembler::Success;
3852 
3853   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
3854   unsigned Rt = fieldFromInstruction(Insn, 0, 4);
3855   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3856   unsigned pred = fieldFromInstruction(Insn, 28, 4);
3857 
3858   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
3859     return MCDisassembler::Fail;
3860 
3861   if (Rn == 0xF || Rd == Rn || Rd == Rt || Rd == Rt+1)
3862     S = MCDisassembler::SoftFail;
3863 
3864   if (!Check(S, DecodeGPRPairRegisterClass(Inst, Rt, Address, Decoder)))
3865     return MCDisassembler::Fail;
3866   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3867     return MCDisassembler::Fail;
3868   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3869     return MCDisassembler::Fail;
3870 
3871   return S;
3872 }
3873 
3874 static DecodeStatus DecodeLDRPreImm(MCInst &Inst, unsigned Insn,
3875                             uint64_t Address, const void *Decoder) {
3876   DecodeStatus S = MCDisassembler::Success;
3877 
3878   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3879   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3880   unsigned imm = fieldFromInstruction(Insn, 0, 12);
3881   imm |= fieldFromInstruction(Insn, 16, 4) << 13;
3882   imm |= fieldFromInstruction(Insn, 23, 1) << 12;
3883   unsigned pred = fieldFromInstruction(Insn, 28, 4);
3884 
3885   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3886 
3887   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3888     return MCDisassembler::Fail;
3889   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3890     return MCDisassembler::Fail;
3891   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
3892     return MCDisassembler::Fail;
3893   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3894     return MCDisassembler::Fail;
3895 
3896   return S;
3897 }
3898 
3899 static DecodeStatus DecodeLDRPreReg(MCInst &Inst, unsigned Insn,
3900                             uint64_t Address, const void *Decoder) {
3901   DecodeStatus S = MCDisassembler::Success;
3902 
3903   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3904   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3905   unsigned imm = fieldFromInstruction(Insn, 0, 12);
3906   imm |= fieldFromInstruction(Insn, 16, 4) << 13;
3907   imm |= fieldFromInstruction(Insn, 23, 1) << 12;
3908   unsigned pred = fieldFromInstruction(Insn, 28, 4);
3909   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3910 
3911   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3912   if (Rm == 0xF) S = MCDisassembler::SoftFail;
3913 
3914   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3915     return MCDisassembler::Fail;
3916   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3917     return MCDisassembler::Fail;
3918   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
3919     return MCDisassembler::Fail;
3920   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3921     return MCDisassembler::Fail;
3922 
3923   return S;
3924 }
3925 
3926 
3927 static DecodeStatus DecodeSTRPreImm(MCInst &Inst, unsigned Insn,
3928                             uint64_t Address, const void *Decoder) {
3929   DecodeStatus S = MCDisassembler::Success;
3930 
3931   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3932   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3933   unsigned imm = fieldFromInstruction(Insn, 0, 12);
3934   imm |= fieldFromInstruction(Insn, 16, 4) << 13;
3935   imm |= fieldFromInstruction(Insn, 23, 1) << 12;
3936   unsigned pred = fieldFromInstruction(Insn, 28, 4);
3937 
3938   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3939 
3940   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3941     return MCDisassembler::Fail;
3942   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3943     return MCDisassembler::Fail;
3944   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
3945     return MCDisassembler::Fail;
3946   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3947     return MCDisassembler::Fail;
3948 
3949   return S;
3950 }
3951 
3952 static DecodeStatus DecodeSTRPreReg(MCInst &Inst, unsigned Insn,
3953                             uint64_t Address, const void *Decoder) {
3954   DecodeStatus S = MCDisassembler::Success;
3955 
3956   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3957   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3958   unsigned imm = fieldFromInstruction(Insn, 0, 12);
3959   imm |= fieldFromInstruction(Insn, 16, 4) << 13;
3960   imm |= fieldFromInstruction(Insn, 23, 1) << 12;
3961   unsigned pred = fieldFromInstruction(Insn, 28, 4);
3962 
3963   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3964 
3965   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3966     return MCDisassembler::Fail;
3967   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3968     return MCDisassembler::Fail;
3969   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
3970     return MCDisassembler::Fail;
3971   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3972     return MCDisassembler::Fail;
3973 
3974   return S;
3975 }
3976 
3977 static DecodeStatus DecodeVLD1LN(MCInst &Inst, unsigned Insn,
3978                          uint64_t Address, const void *Decoder) {
3979   DecodeStatus S = MCDisassembler::Success;
3980 
3981   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3982   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3983   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
3984   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
3985   unsigned size = fieldFromInstruction(Insn, 10, 2);
3986 
3987   unsigned align = 0;
3988   unsigned index = 0;
3989   switch (size) {
3990     default:
3991       return MCDisassembler::Fail;
3992     case 0:
3993       if (fieldFromInstruction(Insn, 4, 1))
3994         return MCDisassembler::Fail; // UNDEFINED
3995       index = fieldFromInstruction(Insn, 5, 3);
3996       break;
3997     case 1:
3998       if (fieldFromInstruction(Insn, 5, 1))
3999         return MCDisassembler::Fail; // UNDEFINED
4000       index = fieldFromInstruction(Insn, 6, 2);
4001       if (fieldFromInstruction(Insn, 4, 1))
4002         align = 2;
4003       break;
4004     case 2:
4005       if (fieldFromInstruction(Insn, 6, 1))
4006         return MCDisassembler::Fail; // UNDEFINED
4007       index = fieldFromInstruction(Insn, 7, 1);
4008 
4009       switch (fieldFromInstruction(Insn, 4, 2)) {
4010         case 0 :
4011           align = 0; break;
4012         case 3:
4013           align = 4; break;
4014         default:
4015           return MCDisassembler::Fail;
4016       }
4017       break;
4018   }
4019 
4020   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4021     return MCDisassembler::Fail;
4022   if (Rm != 0xF) { // Writeback
4023     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4024       return MCDisassembler::Fail;
4025   }
4026   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4027     return MCDisassembler::Fail;
4028   Inst.addOperand(MCOperand::CreateImm(align));
4029   if (Rm != 0xF) {
4030     if (Rm != 0xD) {
4031       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4032         return MCDisassembler::Fail;
4033     } else
4034       Inst.addOperand(MCOperand::CreateReg(0));
4035   }
4036 
4037   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4038     return MCDisassembler::Fail;
4039   Inst.addOperand(MCOperand::CreateImm(index));
4040 
4041   return S;
4042 }
4043 
4044 static DecodeStatus DecodeVST1LN(MCInst &Inst, unsigned Insn,
4045                          uint64_t Address, const void *Decoder) {
4046   DecodeStatus S = MCDisassembler::Success;
4047 
4048   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4049   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4050   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4051   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4052   unsigned size = fieldFromInstruction(Insn, 10, 2);
4053 
4054   unsigned align = 0;
4055   unsigned index = 0;
4056   switch (size) {
4057     default:
4058       return MCDisassembler::Fail;
4059     case 0:
4060       if (fieldFromInstruction(Insn, 4, 1))
4061         return MCDisassembler::Fail; // UNDEFINED
4062       index = fieldFromInstruction(Insn, 5, 3);
4063       break;
4064     case 1:
4065       if (fieldFromInstruction(Insn, 5, 1))
4066         return MCDisassembler::Fail; // UNDEFINED
4067       index = fieldFromInstruction(Insn, 6, 2);
4068       if (fieldFromInstruction(Insn, 4, 1))
4069         align = 2;
4070       break;
4071     case 2:
4072       if (fieldFromInstruction(Insn, 6, 1))
4073         return MCDisassembler::Fail; // UNDEFINED
4074       index = fieldFromInstruction(Insn, 7, 1);
4075 
4076       switch (fieldFromInstruction(Insn, 4, 2)) {
4077         case 0:
4078           align = 0; break;
4079         case 3:
4080           align = 4; break;
4081         default:
4082           return MCDisassembler::Fail;
4083       }
4084       break;
4085   }
4086 
4087   if (Rm != 0xF) { // Writeback
4088     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4089     return MCDisassembler::Fail;
4090   }
4091   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4092     return MCDisassembler::Fail;
4093   Inst.addOperand(MCOperand::CreateImm(align));
4094   if (Rm != 0xF) {
4095     if (Rm != 0xD) {
4096       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4097     return MCDisassembler::Fail;
4098     } else
4099       Inst.addOperand(MCOperand::CreateReg(0));
4100   }
4101 
4102   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4103     return MCDisassembler::Fail;
4104   Inst.addOperand(MCOperand::CreateImm(index));
4105 
4106   return S;
4107 }
4108 
4109 
4110 static DecodeStatus DecodeVLD2LN(MCInst &Inst, unsigned Insn,
4111                          uint64_t Address, const void *Decoder) {
4112   DecodeStatus S = MCDisassembler::Success;
4113 
4114   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4115   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4116   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4117   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4118   unsigned size = fieldFromInstruction(Insn, 10, 2);
4119 
4120   unsigned align = 0;
4121   unsigned index = 0;
4122   unsigned inc = 1;
4123   switch (size) {
4124     default:
4125       return MCDisassembler::Fail;
4126     case 0:
4127       index = fieldFromInstruction(Insn, 5, 3);
4128       if (fieldFromInstruction(Insn, 4, 1))
4129         align = 2;
4130       break;
4131     case 1:
4132       index = fieldFromInstruction(Insn, 6, 2);
4133       if (fieldFromInstruction(Insn, 4, 1))
4134         align = 4;
4135       if (fieldFromInstruction(Insn, 5, 1))
4136         inc = 2;
4137       break;
4138     case 2:
4139       if (fieldFromInstruction(Insn, 5, 1))
4140         return MCDisassembler::Fail; // UNDEFINED
4141       index = fieldFromInstruction(Insn, 7, 1);
4142       if (fieldFromInstruction(Insn, 4, 1) != 0)
4143         align = 8;
4144       if (fieldFromInstruction(Insn, 6, 1))
4145         inc = 2;
4146       break;
4147   }
4148 
4149   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4150     return MCDisassembler::Fail;
4151   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4152     return MCDisassembler::Fail;
4153   if (Rm != 0xF) { // Writeback
4154     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4155       return MCDisassembler::Fail;
4156   }
4157   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4158     return MCDisassembler::Fail;
4159   Inst.addOperand(MCOperand::CreateImm(align));
4160   if (Rm != 0xF) {
4161     if (Rm != 0xD) {
4162       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4163         return MCDisassembler::Fail;
4164     } else
4165       Inst.addOperand(MCOperand::CreateReg(0));
4166   }
4167 
4168   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4169     return MCDisassembler::Fail;
4170   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4171     return MCDisassembler::Fail;
4172   Inst.addOperand(MCOperand::CreateImm(index));
4173 
4174   return S;
4175 }
4176 
4177 static DecodeStatus DecodeVST2LN(MCInst &Inst, unsigned Insn,
4178                          uint64_t Address, const void *Decoder) {
4179   DecodeStatus S = MCDisassembler::Success;
4180 
4181   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4182   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4183   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4184   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4185   unsigned size = fieldFromInstruction(Insn, 10, 2);
4186 
4187   unsigned align = 0;
4188   unsigned index = 0;
4189   unsigned inc = 1;
4190   switch (size) {
4191     default:
4192       return MCDisassembler::Fail;
4193     case 0:
4194       index = fieldFromInstruction(Insn, 5, 3);
4195       if (fieldFromInstruction(Insn, 4, 1))
4196         align = 2;
4197       break;
4198     case 1:
4199       index = fieldFromInstruction(Insn, 6, 2);
4200       if (fieldFromInstruction(Insn, 4, 1))
4201         align = 4;
4202       if (fieldFromInstruction(Insn, 5, 1))
4203         inc = 2;
4204       break;
4205     case 2:
4206       if (fieldFromInstruction(Insn, 5, 1))
4207         return MCDisassembler::Fail; // UNDEFINED
4208       index = fieldFromInstruction(Insn, 7, 1);
4209       if (fieldFromInstruction(Insn, 4, 1) != 0)
4210         align = 8;
4211       if (fieldFromInstruction(Insn, 6, 1))
4212         inc = 2;
4213       break;
4214   }
4215 
4216   if (Rm != 0xF) { // Writeback
4217     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4218       return MCDisassembler::Fail;
4219   }
4220   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4221     return MCDisassembler::Fail;
4222   Inst.addOperand(MCOperand::CreateImm(align));
4223   if (Rm != 0xF) {
4224     if (Rm != 0xD) {
4225       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4226         return MCDisassembler::Fail;
4227     } else
4228       Inst.addOperand(MCOperand::CreateReg(0));
4229   }
4230 
4231   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4232     return MCDisassembler::Fail;
4233   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4234     return MCDisassembler::Fail;
4235   Inst.addOperand(MCOperand::CreateImm(index));
4236 
4237   return S;
4238 }
4239 
4240 
4241 static DecodeStatus DecodeVLD3LN(MCInst &Inst, unsigned Insn,
4242                          uint64_t Address, const void *Decoder) {
4243   DecodeStatus S = MCDisassembler::Success;
4244 
4245   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4246   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4247   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4248   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4249   unsigned size = fieldFromInstruction(Insn, 10, 2);
4250 
4251   unsigned align = 0;
4252   unsigned index = 0;
4253   unsigned inc = 1;
4254   switch (size) {
4255     default:
4256       return MCDisassembler::Fail;
4257     case 0:
4258       if (fieldFromInstruction(Insn, 4, 1))
4259         return MCDisassembler::Fail; // UNDEFINED
4260       index = fieldFromInstruction(Insn, 5, 3);
4261       break;
4262     case 1:
4263       if (fieldFromInstruction(Insn, 4, 1))
4264         return MCDisassembler::Fail; // UNDEFINED
4265       index = fieldFromInstruction(Insn, 6, 2);
4266       if (fieldFromInstruction(Insn, 5, 1))
4267         inc = 2;
4268       break;
4269     case 2:
4270       if (fieldFromInstruction(Insn, 4, 2))
4271         return MCDisassembler::Fail; // UNDEFINED
4272       index = fieldFromInstruction(Insn, 7, 1);
4273       if (fieldFromInstruction(Insn, 6, 1))
4274         inc = 2;
4275       break;
4276   }
4277 
4278   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4279     return MCDisassembler::Fail;
4280   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4281     return MCDisassembler::Fail;
4282   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
4283     return MCDisassembler::Fail;
4284 
4285   if (Rm != 0xF) { // Writeback
4286     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4287     return MCDisassembler::Fail;
4288   }
4289   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4290     return MCDisassembler::Fail;
4291   Inst.addOperand(MCOperand::CreateImm(align));
4292   if (Rm != 0xF) {
4293     if (Rm != 0xD) {
4294       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4295     return MCDisassembler::Fail;
4296     } else
4297       Inst.addOperand(MCOperand::CreateReg(0));
4298   }
4299 
4300   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4301     return MCDisassembler::Fail;
4302   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4303     return MCDisassembler::Fail;
4304   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
4305     return MCDisassembler::Fail;
4306   Inst.addOperand(MCOperand::CreateImm(index));
4307 
4308   return S;
4309 }
4310 
4311 static DecodeStatus DecodeVST3LN(MCInst &Inst, unsigned Insn,
4312                          uint64_t Address, const void *Decoder) {
4313   DecodeStatus S = MCDisassembler::Success;
4314 
4315   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4316   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4317   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4318   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4319   unsigned size = fieldFromInstruction(Insn, 10, 2);
4320 
4321   unsigned align = 0;
4322   unsigned index = 0;
4323   unsigned inc = 1;
4324   switch (size) {
4325     default:
4326       return MCDisassembler::Fail;
4327     case 0:
4328       if (fieldFromInstruction(Insn, 4, 1))
4329         return MCDisassembler::Fail; // UNDEFINED
4330       index = fieldFromInstruction(Insn, 5, 3);
4331       break;
4332     case 1:
4333       if (fieldFromInstruction(Insn, 4, 1))
4334         return MCDisassembler::Fail; // UNDEFINED
4335       index = fieldFromInstruction(Insn, 6, 2);
4336       if (fieldFromInstruction(Insn, 5, 1))
4337         inc = 2;
4338       break;
4339     case 2:
4340       if (fieldFromInstruction(Insn, 4, 2))
4341         return MCDisassembler::Fail; // UNDEFINED
4342       index = fieldFromInstruction(Insn, 7, 1);
4343       if (fieldFromInstruction(Insn, 6, 1))
4344         inc = 2;
4345       break;
4346   }
4347 
4348   if (Rm != 0xF) { // Writeback
4349     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4350     return MCDisassembler::Fail;
4351   }
4352   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4353     return MCDisassembler::Fail;
4354   Inst.addOperand(MCOperand::CreateImm(align));
4355   if (Rm != 0xF) {
4356     if (Rm != 0xD) {
4357       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4358     return MCDisassembler::Fail;
4359     } else
4360       Inst.addOperand(MCOperand::CreateReg(0));
4361   }
4362 
4363   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4364     return MCDisassembler::Fail;
4365   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4366     return MCDisassembler::Fail;
4367   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
4368     return MCDisassembler::Fail;
4369   Inst.addOperand(MCOperand::CreateImm(index));
4370 
4371   return S;
4372 }
4373 
4374 
4375 static DecodeStatus DecodeVLD4LN(MCInst &Inst, unsigned Insn,
4376                          uint64_t Address, const void *Decoder) {
4377   DecodeStatus S = MCDisassembler::Success;
4378 
4379   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4380   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4381   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4382   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4383   unsigned size = fieldFromInstruction(Insn, 10, 2);
4384 
4385   unsigned align = 0;
4386   unsigned index = 0;
4387   unsigned inc = 1;
4388   switch (size) {
4389     default:
4390       return MCDisassembler::Fail;
4391     case 0:
4392       if (fieldFromInstruction(Insn, 4, 1))
4393         align = 4;
4394       index = fieldFromInstruction(Insn, 5, 3);
4395       break;
4396     case 1:
4397       if (fieldFromInstruction(Insn, 4, 1))
4398         align = 8;
4399       index = fieldFromInstruction(Insn, 6, 2);
4400       if (fieldFromInstruction(Insn, 5, 1))
4401         inc = 2;
4402       break;
4403     case 2:
4404       switch (fieldFromInstruction(Insn, 4, 2)) {
4405         case 0:
4406           align = 0; break;
4407         case 3:
4408           return MCDisassembler::Fail;
4409         default:
4410           align = 4 << fieldFromInstruction(Insn, 4, 2); break;
4411       }
4412 
4413       index = fieldFromInstruction(Insn, 7, 1);
4414       if (fieldFromInstruction(Insn, 6, 1))
4415         inc = 2;
4416       break;
4417   }
4418 
4419   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4420     return MCDisassembler::Fail;
4421   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4422     return MCDisassembler::Fail;
4423   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
4424     return MCDisassembler::Fail;
4425   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
4426     return MCDisassembler::Fail;
4427 
4428   if (Rm != 0xF) { // Writeback
4429     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4430       return MCDisassembler::Fail;
4431   }
4432   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4433     return MCDisassembler::Fail;
4434   Inst.addOperand(MCOperand::CreateImm(align));
4435   if (Rm != 0xF) {
4436     if (Rm != 0xD) {
4437       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4438         return MCDisassembler::Fail;
4439     } else
4440       Inst.addOperand(MCOperand::CreateReg(0));
4441   }
4442 
4443   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4444     return MCDisassembler::Fail;
4445   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4446     return MCDisassembler::Fail;
4447   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
4448     return MCDisassembler::Fail;
4449   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
4450     return MCDisassembler::Fail;
4451   Inst.addOperand(MCOperand::CreateImm(index));
4452 
4453   return S;
4454 }
4455 
4456 static DecodeStatus DecodeVST4LN(MCInst &Inst, unsigned Insn,
4457                          uint64_t Address, const void *Decoder) {
4458   DecodeStatus S = MCDisassembler::Success;
4459 
4460   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4461   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4462   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4463   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4464   unsigned size = fieldFromInstruction(Insn, 10, 2);
4465 
4466   unsigned align = 0;
4467   unsigned index = 0;
4468   unsigned inc = 1;
4469   switch (size) {
4470     default:
4471       return MCDisassembler::Fail;
4472     case 0:
4473       if (fieldFromInstruction(Insn, 4, 1))
4474         align = 4;
4475       index = fieldFromInstruction(Insn, 5, 3);
4476       break;
4477     case 1:
4478       if (fieldFromInstruction(Insn, 4, 1))
4479         align = 8;
4480       index = fieldFromInstruction(Insn, 6, 2);
4481       if (fieldFromInstruction(Insn, 5, 1))
4482         inc = 2;
4483       break;
4484     case 2:
4485       switch (fieldFromInstruction(Insn, 4, 2)) {
4486         case 0:
4487           align = 0; break;
4488         case 3:
4489           return MCDisassembler::Fail;
4490         default:
4491           align = 4 << fieldFromInstruction(Insn, 4, 2); break;
4492       }
4493 
4494       index = fieldFromInstruction(Insn, 7, 1);
4495       if (fieldFromInstruction(Insn, 6, 1))
4496         inc = 2;
4497       break;
4498   }
4499 
4500   if (Rm != 0xF) { // Writeback
4501     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4502     return MCDisassembler::Fail;
4503   }
4504   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4505     return MCDisassembler::Fail;
4506   Inst.addOperand(MCOperand::CreateImm(align));
4507   if (Rm != 0xF) {
4508     if (Rm != 0xD) {
4509       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4510     return MCDisassembler::Fail;
4511     } else
4512       Inst.addOperand(MCOperand::CreateReg(0));
4513   }
4514 
4515   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4516     return MCDisassembler::Fail;
4517   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4518     return MCDisassembler::Fail;
4519   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
4520     return MCDisassembler::Fail;
4521   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
4522     return MCDisassembler::Fail;
4523   Inst.addOperand(MCOperand::CreateImm(index));
4524 
4525   return S;
4526 }
4527 
4528 static DecodeStatus DecodeVMOVSRR(MCInst &Inst, unsigned Insn,
4529                                   uint64_t Address, const void *Decoder) {
4530   DecodeStatus S = MCDisassembler::Success;
4531   unsigned Rt  = fieldFromInstruction(Insn, 12, 4);
4532   unsigned Rt2 = fieldFromInstruction(Insn, 16, 4);
4533   unsigned Rm  = fieldFromInstruction(Insn,  5, 1);
4534   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4535   Rm |= fieldFromInstruction(Insn, 0, 4) << 1;
4536 
4537   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
4538     S = MCDisassembler::SoftFail;
4539 
4540   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
4541     return MCDisassembler::Fail;
4542   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
4543     return MCDisassembler::Fail;
4544   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
4545     return MCDisassembler::Fail;
4546   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
4547     return MCDisassembler::Fail;
4548   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4549     return MCDisassembler::Fail;
4550 
4551   return S;
4552 }
4553 
4554 static DecodeStatus DecodeVMOVRRS(MCInst &Inst, unsigned Insn,
4555                                   uint64_t Address, const void *Decoder) {
4556   DecodeStatus S = MCDisassembler::Success;
4557   unsigned Rt  = fieldFromInstruction(Insn, 12, 4);
4558   unsigned Rt2 = fieldFromInstruction(Insn, 16, 4);
4559   unsigned Rm  = fieldFromInstruction(Insn,  5, 1);
4560   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4561   Rm |= fieldFromInstruction(Insn, 0, 4) << 1;
4562 
4563   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
4564     S = MCDisassembler::SoftFail;
4565 
4566   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
4567     return MCDisassembler::Fail;
4568   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
4569     return MCDisassembler::Fail;
4570   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
4571     return MCDisassembler::Fail;
4572   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
4573     return MCDisassembler::Fail;
4574   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4575     return MCDisassembler::Fail;
4576 
4577   return S;
4578 }
4579 
4580 static DecodeStatus DecodeIT(MCInst &Inst, unsigned Insn,
4581                              uint64_t Address, const void *Decoder) {
4582   DecodeStatus S = MCDisassembler::Success;
4583   unsigned pred = fieldFromInstruction(Insn, 4, 4);
4584   unsigned mask = fieldFromInstruction(Insn, 0, 4);
4585 
4586   if (pred == 0xF) {
4587     pred = 0xE;
4588     S = MCDisassembler::SoftFail;
4589   }
4590 
4591   if (mask == 0x0) {
4592     mask |= 0x8;
4593     S = MCDisassembler::SoftFail;
4594   }
4595 
4596   Inst.addOperand(MCOperand::CreateImm(pred));
4597   Inst.addOperand(MCOperand::CreateImm(mask));
4598   return S;
4599 }
4600 
4601 static DecodeStatus
4602 DecodeT2LDRDPreInstruction(MCInst &Inst, unsigned Insn,
4603                            uint64_t Address, const void *Decoder) {
4604   DecodeStatus S = MCDisassembler::Success;
4605 
4606   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
4607   unsigned Rt2 = fieldFromInstruction(Insn, 8, 4);
4608   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4609   unsigned addr = fieldFromInstruction(Insn, 0, 8);
4610   unsigned W = fieldFromInstruction(Insn, 21, 1);
4611   unsigned U = fieldFromInstruction(Insn, 23, 1);
4612   unsigned P = fieldFromInstruction(Insn, 24, 1);
4613   bool writeback = (W == 1) | (P == 0);
4614 
4615   addr |= (U << 8) | (Rn << 9);
4616 
4617   if (writeback && (Rn == Rt || Rn == Rt2))
4618     Check(S, MCDisassembler::SoftFail);
4619   if (Rt == Rt2)
4620     Check(S, MCDisassembler::SoftFail);
4621 
4622   // Rt
4623   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
4624     return MCDisassembler::Fail;
4625   // Rt2
4626   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
4627     return MCDisassembler::Fail;
4628   // Writeback operand
4629   if (!Check(S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
4630     return MCDisassembler::Fail;
4631   // addr
4632   if (!Check(S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
4633     return MCDisassembler::Fail;
4634 
4635   return S;
4636 }
4637 
4638 static DecodeStatus
4639 DecodeT2STRDPreInstruction(MCInst &Inst, unsigned Insn,
4640                            uint64_t Address, const void *Decoder) {
4641   DecodeStatus S = MCDisassembler::Success;
4642 
4643   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
4644   unsigned Rt2 = fieldFromInstruction(Insn, 8, 4);
4645   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4646   unsigned addr = fieldFromInstruction(Insn, 0, 8);
4647   unsigned W = fieldFromInstruction(Insn, 21, 1);
4648   unsigned U = fieldFromInstruction(Insn, 23, 1);
4649   unsigned P = fieldFromInstruction(Insn, 24, 1);
4650   bool writeback = (W == 1) | (P == 0);
4651 
4652   addr |= (U << 8) | (Rn << 9);
4653 
4654   if (writeback && (Rn == Rt || Rn == Rt2))
4655     Check(S, MCDisassembler::SoftFail);
4656 
4657   // Writeback operand
4658   if (!Check(S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
4659     return MCDisassembler::Fail;
4660   // Rt
4661   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
4662     return MCDisassembler::Fail;
4663   // Rt2
4664   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
4665     return MCDisassembler::Fail;
4666   // addr
4667   if (!Check(S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
4668     return MCDisassembler::Fail;
4669 
4670   return S;
4671 }
4672 
4673 static DecodeStatus DecodeT2Adr(MCInst &Inst, uint32_t Insn,
4674                                 uint64_t Address, const void *Decoder) {
4675   unsigned sign1 = fieldFromInstruction(Insn, 21, 1);
4676   unsigned sign2 = fieldFromInstruction(Insn, 23, 1);
4677   if (sign1 != sign2) return MCDisassembler::Fail;
4678 
4679   unsigned Val = fieldFromInstruction(Insn, 0, 8);
4680   Val |= fieldFromInstruction(Insn, 12, 3) << 8;
4681   Val |= fieldFromInstruction(Insn, 26, 1) << 11;
4682   Val |= sign1 << 12;
4683   Inst.addOperand(MCOperand::CreateImm(SignExtend32<13>(Val)));
4684 
4685   return MCDisassembler::Success;
4686 }
4687 
4688 static DecodeStatus DecodeT2ShifterImmOperand(MCInst &Inst, uint32_t Val,
4689                                               uint64_t Address,
4690                                               const void *Decoder) {
4691   DecodeStatus S = MCDisassembler::Success;
4692 
4693   // Shift of "asr #32" is not allowed in Thumb2 mode.
4694   if (Val == 0x20) S = MCDisassembler::SoftFail;
4695   Inst.addOperand(MCOperand::CreateImm(Val));
4696   return S;
4697 }
4698 
4699 static DecodeStatus DecodeSwap(MCInst &Inst, unsigned Insn,
4700                                uint64_t Address, const void *Decoder) {
4701   unsigned Rt   = fieldFromInstruction(Insn, 12, 4);
4702   unsigned Rt2  = fieldFromInstruction(Insn, 0,  4);
4703   unsigned Rn   = fieldFromInstruction(Insn, 16, 4);
4704   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4705 
4706   if (pred == 0xF)
4707     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
4708 
4709   DecodeStatus S = MCDisassembler::Success;
4710 
4711   if (Rt == Rn || Rn == Rt2)
4712     S = MCDisassembler::SoftFail;
4713 
4714   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
4715     return MCDisassembler::Fail;
4716   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt2, Address, Decoder)))
4717     return MCDisassembler::Fail;
4718   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
4719     return MCDisassembler::Fail;
4720   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4721     return MCDisassembler::Fail;
4722 
4723   return S;
4724 }
4725 
4726 static DecodeStatus DecodeVCVTD(MCInst &Inst, unsigned Insn,
4727                                 uint64_t Address, const void *Decoder) {
4728   unsigned Vd = (fieldFromInstruction(Insn, 12, 4) << 0);
4729   Vd |= (fieldFromInstruction(Insn, 22, 1) << 4);
4730   unsigned Vm = (fieldFromInstruction(Insn, 0, 4) << 0);
4731   Vm |= (fieldFromInstruction(Insn, 5, 1) << 4);
4732   unsigned imm = fieldFromInstruction(Insn, 16, 6);
4733   unsigned cmode = fieldFromInstruction(Insn, 8, 4);
4734   unsigned op = fieldFromInstruction(Insn, 5, 1);
4735 
4736   DecodeStatus S = MCDisassembler::Success;
4737 
4738   // VMOVv2f32 is ambiguous with these decodings.
4739   if (!(imm & 0x38) && cmode == 0xF) {
4740     if (op == 1) return MCDisassembler::Fail;
4741     Inst.setOpcode(ARM::VMOVv2f32);
4742     return DecodeNEONModImmInstruction(Inst, Insn, Address, Decoder);
4743   }
4744 
4745   if (!(imm & 0x20)) return MCDisassembler::Fail;
4746 
4747   if (!Check(S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)))
4748     return MCDisassembler::Fail;
4749   if (!Check(S, DecodeDPRRegisterClass(Inst, Vm, Address, Decoder)))
4750     return MCDisassembler::Fail;
4751   Inst.addOperand(MCOperand::CreateImm(64 - imm));
4752 
4753   return S;
4754 }
4755 
4756 static DecodeStatus DecodeVCVTQ(MCInst &Inst, unsigned Insn,
4757                                 uint64_t Address, const void *Decoder) {
4758   unsigned Vd = (fieldFromInstruction(Insn, 12, 4) << 0);
4759   Vd |= (fieldFromInstruction(Insn, 22, 1) << 4);
4760   unsigned Vm = (fieldFromInstruction(Insn, 0, 4) << 0);
4761   Vm |= (fieldFromInstruction(Insn, 5, 1) << 4);
4762   unsigned imm = fieldFromInstruction(Insn, 16, 6);
4763   unsigned cmode = fieldFromInstruction(Insn, 8, 4);
4764   unsigned op = fieldFromInstruction(Insn, 5, 1);
4765 
4766   DecodeStatus S = MCDisassembler::Success;
4767 
4768   // VMOVv4f32 is ambiguous with these decodings.
4769   if (!(imm & 0x38) && cmode == 0xF) {
4770     if (op == 1) return MCDisassembler::Fail;
4771     Inst.setOpcode(ARM::VMOVv4f32);
4772     return DecodeNEONModImmInstruction(Inst, Insn, Address, Decoder);
4773   }
4774 
4775   if (!(imm & 0x20)) return MCDisassembler::Fail;
4776 
4777   if (!Check(S, DecodeQPRRegisterClass(Inst, Vd, Address, Decoder)))
4778     return MCDisassembler::Fail;
4779   if (!Check(S, DecodeQPRRegisterClass(Inst, Vm, Address, Decoder)))
4780     return MCDisassembler::Fail;
4781   Inst.addOperand(MCOperand::CreateImm(64 - imm));
4782 
4783   return S;
4784 }
4785 
4786 static DecodeStatus DecodeImm0_4(MCInst &Inst, unsigned Insn, uint64_t Address,
4787                                  const void *Decoder)
4788 {
4789   unsigned Imm = fieldFromInstruction(Insn, 0, 3);
4790   if (Imm > 4) return MCDisassembler::Fail;
4791   Inst.addOperand(MCOperand::CreateImm(Imm));
4792   return MCDisassembler::Success;
4793 }
4794 
4795 static DecodeStatus DecodeLDR(MCInst &Inst, unsigned Val,
4796                                 uint64_t Address, const void *Decoder) {
4797   DecodeStatus S = MCDisassembler::Success;
4798 
4799   unsigned Rn = fieldFromInstruction(Val, 16, 4);
4800   unsigned Rt = fieldFromInstruction(Val, 12, 4);
4801   unsigned Rm = fieldFromInstruction(Val, 0, 4);
4802   Rm |= (fieldFromInstruction(Val, 23, 1) << 4);
4803   unsigned Cond = fieldFromInstruction(Val, 28, 4);
4804 
4805   if (fieldFromInstruction(Val, 8, 4) != 0 || Rn == Rt)
4806     S = MCDisassembler::SoftFail;
4807 
4808   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
4809     return MCDisassembler::Fail;
4810   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
4811     return MCDisassembler::Fail;
4812   if (!Check(S, DecodeAddrMode7Operand(Inst, Rn, Address, Decoder)))
4813     return MCDisassembler::Fail;
4814   if (!Check(S, DecodePostIdxReg(Inst, Rm, Address, Decoder)))
4815     return MCDisassembler::Fail;
4816   if (!Check(S, DecodePredicateOperand(Inst, Cond, Address, Decoder)))
4817     return MCDisassembler::Fail;
4818 
4819   return S;
4820 }
4821 
4822 static DecodeStatus DecodeMRRC2(llvm::MCInst &Inst, unsigned Val,
4823                                 uint64_t Address, const void *Decoder) {
4824 
4825   DecodeStatus S = MCDisassembler::Success;
4826 
4827   unsigned CRm = fieldFromInstruction(Val, 0, 4);
4828   unsigned opc1 = fieldFromInstruction(Val, 4, 4);
4829   unsigned cop = fieldFromInstruction(Val, 8, 4);
4830   unsigned Rt = fieldFromInstruction(Val, 12, 4);
4831   unsigned Rt2 = fieldFromInstruction(Val, 16, 4);
4832 
4833   if ((cop & ~0x1) == 0xa)
4834     return MCDisassembler::Fail;
4835 
4836   if (Rt == Rt2)
4837     S = MCDisassembler::SoftFail;
4838 
4839   Inst.addOperand(MCOperand::CreateImm(cop));
4840   Inst.addOperand(MCOperand::CreateImm(opc1));
4841   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
4842     return MCDisassembler::Fail;
4843   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt2, Address, Decoder)))
4844     return MCDisassembler::Fail;
4845   Inst.addOperand(MCOperand::CreateImm(CRm));
4846 
4847   return S;
4848 }
4849 
4850