xref: /llvm-project/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp (revision 8d24618975c6e633b00189e1aa990f6763a3c1cd)
1 //===- ARMDisassembler.cpp - Disassembler for ARM/Thumb ISA -----*- C++ -*-===//
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 "ARM.h"
13 #include "ARMSubtarget.h"
14 #include "MCTargetDesc/ARMAddressingModes.h"
15 #include "MCTargetDesc/ARMMCExpr.h"
16 #include "MCTargetDesc/ARMBaseInfo.h"
17 #include "llvm/MC/EDInstInfo.h"
18 #include "llvm/MC/MCInst.h"
19 #include "llvm/MC/MCInstrDesc.h"
20 #include "llvm/MC/MCExpr.h"
21 #include "llvm/MC/MCContext.h"
22 #include "llvm/MC/MCDisassembler.h"
23 #include "llvm/Support/Debug.h"
24 #include "llvm/Support/MemoryObject.h"
25 #include "llvm/Support/ErrorHandling.h"
26 #include "llvm/Support/TargetRegistry.h"
27 #include "llvm/Support/raw_ostream.h"
28 
29 using namespace llvm;
30 
31 typedef MCDisassembler::DecodeStatus DecodeStatus;
32 
33 namespace {
34 /// ARMDisassembler - ARM disassembler for all ARM platforms.
35 class ARMDisassembler : public MCDisassembler {
36 public:
37   /// Constructor     - Initializes the disassembler.
38   ///
39   ARMDisassembler(const MCSubtargetInfo &STI) :
40     MCDisassembler(STI) {
41   }
42 
43   ~ARMDisassembler() {
44   }
45 
46   /// getInstruction - See MCDisassembler.
47   DecodeStatus getInstruction(MCInst &instr,
48                               uint64_t &size,
49                               const MemoryObject &region,
50                               uint64_t address,
51                               raw_ostream &vStream,
52                               raw_ostream &cStream) const;
53 
54   /// getEDInfo - See MCDisassembler.
55   EDInstInfo *getEDInfo() const;
56 private:
57 };
58 
59 /// ThumbDisassembler - Thumb disassembler for all Thumb platforms.
60 class ThumbDisassembler : public MCDisassembler {
61 public:
62   /// Constructor     - Initializes the disassembler.
63   ///
64   ThumbDisassembler(const MCSubtargetInfo &STI) :
65     MCDisassembler(STI) {
66   }
67 
68   ~ThumbDisassembler() {
69   }
70 
71   /// getInstruction - See MCDisassembler.
72   DecodeStatus getInstruction(MCInst &instr,
73                               uint64_t &size,
74                               const MemoryObject &region,
75                               uint64_t address,
76                               raw_ostream &vStream,
77                               raw_ostream &cStream) const;
78 
79   /// getEDInfo - See MCDisassembler.
80   EDInstInfo *getEDInfo() const;
81 private:
82   mutable std::vector<unsigned> ITBlock;
83   DecodeStatus AddThumbPredicate(MCInst&) const;
84   void UpdateThumbVFPPredicate(MCInst&) const;
85 };
86 }
87 
88 static bool Check(DecodeStatus &Out, DecodeStatus In) {
89   switch (In) {
90     case MCDisassembler::Success:
91       // Out stays the same.
92       return true;
93     case MCDisassembler::SoftFail:
94       Out = In;
95       return true;
96     case MCDisassembler::Fail:
97       Out = In;
98       return false;
99   }
100   return false;
101 }
102 
103 
104 // Forward declare these because the autogenerated code will reference them.
105 // Definitions are further down.
106 static DecodeStatus DecodeGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
107                                    uint64_t Address, const void *Decoder);
108 static DecodeStatus DecodeGPRnopcRegisterClass(llvm::MCInst &Inst,
109                                                unsigned RegNo, uint64_t Address,
110                                                const void *Decoder);
111 static DecodeStatus DecodetGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
112                                    uint64_t Address, const void *Decoder);
113 static DecodeStatus DecodetcGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
114                                    uint64_t Address, const void *Decoder);
115 static DecodeStatus DecoderGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
116                                    uint64_t Address, const void *Decoder);
117 static DecodeStatus DecodeSPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
118                                    uint64_t Address, const void *Decoder);
119 static DecodeStatus DecodeDPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
120                                    uint64_t Address, const void *Decoder);
121 static DecodeStatus DecodeDPR_8RegisterClass(llvm::MCInst &Inst, unsigned RegNo,
122                                    uint64_t Address, const void *Decoder);
123 static DecodeStatus DecodeDPR_VFP2RegisterClass(llvm::MCInst &Inst,
124                                                 unsigned RegNo,
125                                                 uint64_t Address,
126                                                 const void *Decoder);
127 static DecodeStatus DecodeQPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
128                                    uint64_t Address, const void *Decoder);
129 
130 static DecodeStatus DecodePredicateOperand(llvm::MCInst &Inst, unsigned Val,
131                                uint64_t Address, const void *Decoder);
132 static DecodeStatus DecodeCCOutOperand(llvm::MCInst &Inst, unsigned Val,
133                                uint64_t Address, const void *Decoder);
134 static DecodeStatus DecodeSOImmOperand(llvm::MCInst &Inst, unsigned Val,
135                                uint64_t Address, const void *Decoder);
136 static DecodeStatus DecodeRegListOperand(llvm::MCInst &Inst, unsigned Val,
137                                uint64_t Address, const void *Decoder);
138 static DecodeStatus DecodeSPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
139                                uint64_t Address, const void *Decoder);
140 static DecodeStatus DecodeDPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
141                                uint64_t Address, const void *Decoder);
142 
143 static DecodeStatus DecodeBitfieldMaskOperand(llvm::MCInst &Inst, unsigned Insn,
144                                uint64_t Address, const void *Decoder);
145 static DecodeStatus DecodeCopMemInstruction(llvm::MCInst &Inst, unsigned Insn,
146                                uint64_t Address, const void *Decoder);
147 static DecodeStatus DecodeAddrMode2IdxInstruction(llvm::MCInst &Inst,
148                                                   unsigned Insn,
149                                                   uint64_t Address,
150                                                   const void *Decoder);
151 static DecodeStatus DecodeSORegMemOperand(llvm::MCInst &Inst, unsigned Insn,
152                                uint64_t Address, const void *Decoder);
153 static DecodeStatus DecodeAddrMode3Instruction(llvm::MCInst &Inst,unsigned Insn,
154                                uint64_t Address, const void *Decoder);
155 static DecodeStatus DecodeSORegImmOperand(llvm::MCInst &Inst, unsigned Insn,
156                                uint64_t Address, const void *Decoder);
157 static DecodeStatus DecodeSORegRegOperand(llvm::MCInst &Inst, unsigned Insn,
158                                uint64_t Address, const void *Decoder);
159 
160 static DecodeStatus DecodeMemMultipleWritebackInstruction(llvm::MCInst & Inst,
161                                                   unsigned Insn,
162                                                   uint64_t Adddress,
163                                                   const void *Decoder);
164 static DecodeStatus DecodeT2MOVTWInstruction(llvm::MCInst &Inst, unsigned Insn,
165                                uint64_t Address, const void *Decoder);
166 static DecodeStatus DecodeArmMOVTWInstruction(llvm::MCInst &Inst, unsigned Insn,
167                                uint64_t Address, const void *Decoder);
168 static DecodeStatus DecodeSMLAInstruction(llvm::MCInst &Inst, unsigned Insn,
169                                uint64_t Address, const void *Decoder);
170 static DecodeStatus DecodeCPSInstruction(llvm::MCInst &Inst, unsigned Insn,
171                                uint64_t Address, const void *Decoder);
172 static DecodeStatus DecodeT2CPSInstruction(llvm::MCInst &Inst, unsigned Insn,
173                                uint64_t Address, const void *Decoder);
174 static DecodeStatus DecodeAddrModeImm12Operand(llvm::MCInst &Inst, unsigned Val,
175                                uint64_t Address, const void *Decoder);
176 static DecodeStatus DecodeAddrMode5Operand(llvm::MCInst &Inst, unsigned Val,
177                                uint64_t Address, const void *Decoder);
178 static DecodeStatus DecodeAddrMode7Operand(llvm::MCInst &Inst, unsigned Val,
179                                uint64_t Address, const void *Decoder);
180 static DecodeStatus DecodeBranchImmInstruction(llvm::MCInst &Inst,unsigned Insn,
181                                uint64_t Address, const void *Decoder);
182 static DecodeStatus DecodeAddrMode6Operand(llvm::MCInst &Inst, unsigned Val,
183                                uint64_t Address, const void *Decoder);
184 static DecodeStatus DecodeVLDInstruction(llvm::MCInst &Inst, unsigned Val,
185                                uint64_t Address, const void *Decoder);
186 static DecodeStatus DecodeVSTInstruction(llvm::MCInst &Inst, unsigned Val,
187                                uint64_t Address, const void *Decoder);
188 static DecodeStatus DecodeVLD1DupInstruction(llvm::MCInst &Inst, unsigned Val,
189                                uint64_t Address, const void *Decoder);
190 static DecodeStatus DecodeVLD2DupInstruction(llvm::MCInst &Inst, unsigned Val,
191                                uint64_t Address, const void *Decoder);
192 static DecodeStatus DecodeVLD3DupInstruction(llvm::MCInst &Inst, unsigned Val,
193                                uint64_t Address, const void *Decoder);
194 static DecodeStatus DecodeVLD4DupInstruction(llvm::MCInst &Inst, unsigned Val,
195                                uint64_t Address, const void *Decoder);
196 static DecodeStatus DecodeNEONModImmInstruction(llvm::MCInst &Inst,unsigned Val,
197                                uint64_t Address, const void *Decoder);
198 static DecodeStatus DecodeVSHLMaxInstruction(llvm::MCInst &Inst, unsigned Val,
199                                uint64_t Address, const void *Decoder);
200 static DecodeStatus DecodeShiftRight8Imm(llvm::MCInst &Inst, unsigned Val,
201                                uint64_t Address, const void *Decoder);
202 static DecodeStatus DecodeShiftRight16Imm(llvm::MCInst &Inst, unsigned Val,
203                                uint64_t Address, const void *Decoder);
204 static DecodeStatus DecodeShiftRight32Imm(llvm::MCInst &Inst, unsigned Val,
205                                uint64_t Address, const void *Decoder);
206 static DecodeStatus DecodeShiftRight64Imm(llvm::MCInst &Inst, unsigned Val,
207                                uint64_t Address, const void *Decoder);
208 static DecodeStatus DecodeTBLInstruction(llvm::MCInst &Inst, unsigned Insn,
209                                uint64_t Address, const void *Decoder);
210 static DecodeStatus DecodePostIdxReg(llvm::MCInst &Inst, unsigned Insn,
211                                uint64_t Address, const void *Decoder);
212 static DecodeStatus DecodeCoprocessor(llvm::MCInst &Inst, unsigned Insn,
213                                uint64_t Address, const void *Decoder);
214 static DecodeStatus DecodeMemBarrierOption(llvm::MCInst &Inst, unsigned Insn,
215                                uint64_t Address, const void *Decoder);
216 static DecodeStatus DecodeMSRMask(llvm::MCInst &Inst, unsigned Insn,
217                                uint64_t Address, const void *Decoder);
218 static DecodeStatus DecodeDoubleRegLoad(llvm::MCInst &Inst, unsigned Insn,
219                                uint64_t Address, const void *Decoder);
220 static DecodeStatus DecodeDoubleRegStore(llvm::MCInst &Inst, unsigned Insn,
221                                uint64_t Address, const void *Decoder);
222 static DecodeStatus DecodeLDRPreImm(llvm::MCInst &Inst, unsigned Insn,
223                                uint64_t Address, const void *Decoder);
224 static DecodeStatus DecodeLDRPreReg(llvm::MCInst &Inst, unsigned Insn,
225                                uint64_t Address, const void *Decoder);
226 static DecodeStatus DecodeSTRPreImm(llvm::MCInst &Inst, unsigned Insn,
227                                uint64_t Address, const void *Decoder);
228 static DecodeStatus DecodeSTRPreReg(llvm::MCInst &Inst, unsigned Insn,
229                                uint64_t Address, const void *Decoder);
230 static DecodeStatus DecodeVLD1LN(llvm::MCInst &Inst, unsigned Insn,
231                                uint64_t Address, const void *Decoder);
232 static DecodeStatus DecodeVLD2LN(llvm::MCInst &Inst, unsigned Insn,
233                                uint64_t Address, const void *Decoder);
234 static DecodeStatus DecodeVLD3LN(llvm::MCInst &Inst, unsigned Insn,
235                                uint64_t Address, const void *Decoder);
236 static DecodeStatus DecodeVLD4LN(llvm::MCInst &Inst, unsigned Insn,
237                                uint64_t Address, const void *Decoder);
238 static DecodeStatus DecodeVST1LN(llvm::MCInst &Inst, unsigned Insn,
239                                uint64_t Address, const void *Decoder);
240 static DecodeStatus DecodeVST2LN(llvm::MCInst &Inst, unsigned Insn,
241                                uint64_t Address, const void *Decoder);
242 static DecodeStatus DecodeVST3LN(llvm::MCInst &Inst, unsigned Insn,
243                                uint64_t Address, const void *Decoder);
244 static DecodeStatus DecodeVST4LN(llvm::MCInst &Inst, unsigned Insn,
245                                uint64_t Address, const void *Decoder);
246 static DecodeStatus DecodeVMOVSRR(llvm::MCInst &Inst, unsigned Insn,
247                                uint64_t Address, const void *Decoder);
248 static DecodeStatus DecodeVMOVRRS(llvm::MCInst &Inst, unsigned Insn,
249                                uint64_t Address, const void *Decoder);
250 static DecodeStatus DecodeSwap(llvm::MCInst &Inst, unsigned Insn,
251                                uint64_t Address, const void *Decoder);
252 static DecodeStatus DecodeVCVTD(llvm::MCInst &Inst, unsigned Insn,
253                                 uint64_t Address, const void *Decoder);
254 static DecodeStatus DecodeVCVTQ(llvm::MCInst &Inst, unsigned Insn,
255                                 uint64_t Address, const void *Decoder);
256 
257 
258 static DecodeStatus DecodeThumbAddSpecialReg(llvm::MCInst &Inst, uint16_t Insn,
259                                uint64_t Address, const void *Decoder);
260 static DecodeStatus DecodeThumbBROperand(llvm::MCInst &Inst, unsigned Val,
261                                uint64_t Address, const void *Decoder);
262 static DecodeStatus DecodeT2BROperand(llvm::MCInst &Inst, unsigned Val,
263                                uint64_t Address, const void *Decoder);
264 static DecodeStatus DecodeThumbCmpBROperand(llvm::MCInst &Inst, unsigned Val,
265                                uint64_t Address, const void *Decoder);
266 static DecodeStatus DecodeThumbAddrModeRR(llvm::MCInst &Inst, unsigned Val,
267                                uint64_t Address, const void *Decoder);
268 static DecodeStatus DecodeThumbAddrModeIS(llvm::MCInst &Inst, unsigned Val,
269                                uint64_t Address, const void *Decoder);
270 static DecodeStatus DecodeThumbAddrModePC(llvm::MCInst &Inst, unsigned Val,
271                                uint64_t Address, const void *Decoder);
272 static DecodeStatus DecodeThumbAddrModeSP(llvm::MCInst &Inst, unsigned Val,
273                                uint64_t Address, const void *Decoder);
274 static DecodeStatus DecodeT2AddrModeSOReg(llvm::MCInst &Inst, unsigned Val,
275                                uint64_t Address, const void *Decoder);
276 static DecodeStatus DecodeT2LoadShift(llvm::MCInst &Inst, unsigned Val,
277                                uint64_t Address, const void *Decoder);
278 static DecodeStatus DecodeT2Imm8S4(llvm::MCInst &Inst, unsigned Val,
279                                uint64_t Address, const void *Decoder);
280 static DecodeStatus DecodeT2AddrModeImm8s4(llvm::MCInst &Inst, unsigned Val,
281                                uint64_t Address, const void *Decoder);
282 static DecodeStatus DecodeT2AddrModeImm0_1020s4(llvm::MCInst &Inst,unsigned Val,
283                                uint64_t Address, const void *Decoder);
284 static DecodeStatus DecodeT2Imm8(llvm::MCInst &Inst, unsigned Val,
285                                uint64_t Address, const void *Decoder);
286 static DecodeStatus DecodeT2AddrModeImm8(llvm::MCInst &Inst, unsigned Val,
287                                uint64_t Address, const void *Decoder);
288 static DecodeStatus DecodeThumbAddSPImm(llvm::MCInst &Inst, uint16_t Val,
289                                uint64_t Address, const void *Decoder);
290 static DecodeStatus DecodeThumbAddSPReg(llvm::MCInst &Inst, uint16_t Insn,
291                                 uint64_t Address, const void *Decoder);
292 static DecodeStatus DecodeThumbCPS(llvm::MCInst &Inst, uint16_t Insn,
293                                 uint64_t Address, const void *Decoder);
294 static DecodeStatus DecodeThumbBLXOffset(llvm::MCInst &Inst, unsigned Insn,
295                                 uint64_t Address, const void *Decoder);
296 static DecodeStatus DecodeT2AddrModeImm12(llvm::MCInst &Inst, unsigned Val,
297                                 uint64_t Address, const void *Decoder);
298 static DecodeStatus DecodeThumbTableBranch(llvm::MCInst &Inst, unsigned Val,
299                                 uint64_t Address, const void *Decoder);
300 static DecodeStatus DecodeThumb2BCCInstruction(llvm::MCInst &Inst, unsigned Val,
301                                 uint64_t Address, const void *Decoder);
302 static DecodeStatus DecodeT2SOImm(llvm::MCInst &Inst, unsigned Val,
303                                 uint64_t Address, const void *Decoder);
304 static DecodeStatus DecodeThumbBCCTargetOperand(llvm::MCInst &Inst,unsigned Val,
305                                 uint64_t Address, const void *Decoder);
306 static DecodeStatus DecodeThumbBLTargetOperand(llvm::MCInst &Inst, unsigned Val,
307                                 uint64_t Address, const void *Decoder);
308 static DecodeStatus DecodeIT(llvm::MCInst &Inst, unsigned Val,
309                                 uint64_t Address, const void *Decoder);
310 static DecodeStatus DecodeT2LDRDPreInstruction(llvm::MCInst &Inst,unsigned Insn,
311                                uint64_t Address, const void *Decoder);
312 static DecodeStatus DecodeT2STRDPreInstruction(llvm::MCInst &Inst,unsigned Insn,
313                                uint64_t Address, const void *Decoder);
314 static DecodeStatus DecodeT2Adr(llvm::MCInst &Inst, unsigned Val,
315                                 uint64_t Address, const void *Decoder);
316 static DecodeStatus DecodeT2LdStPre(llvm::MCInst &Inst, unsigned Val,
317                                 uint64_t Address, const void *Decoder);
318 static DecodeStatus DecodeT2ShifterImmOperand(llvm::MCInst &Inst, unsigned Val,
319                                 uint64_t Address, const void *Decoder);
320 
321 
322 
323 #include "ARMGenDisassemblerTables.inc"
324 #include "ARMGenInstrInfo.inc"
325 #include "ARMGenEDInfo.inc"
326 
327 static MCDisassembler *createARMDisassembler(const Target &T, const MCSubtargetInfo &STI) {
328   return new ARMDisassembler(STI);
329 }
330 
331 static MCDisassembler *createThumbDisassembler(const Target &T, const MCSubtargetInfo &STI) {
332   return new ThumbDisassembler(STI);
333 }
334 
335 EDInstInfo *ARMDisassembler::getEDInfo() const {
336   return instInfoARM;
337 }
338 
339 EDInstInfo *ThumbDisassembler::getEDInfo() const {
340   return instInfoARM;
341 }
342 
343 DecodeStatus ARMDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
344                                              const MemoryObject &Region,
345                                              uint64_t Address,
346                                              raw_ostream &os,
347                                              raw_ostream &cs) const {
348   CommentStream = &cs;
349 
350   uint8_t bytes[4];
351 
352   assert(!(STI.getFeatureBits() & ARM::ModeThumb) &&
353          "Asked to disassemble an ARM instruction but Subtarget is in Thumb mode!");
354 
355   // We want to read exactly 4 bytes of data.
356   if (Region.readBytes(Address, 4, (uint8_t*)bytes, NULL) == -1) {
357     Size = 0;
358     return MCDisassembler::Fail;
359   }
360 
361   // Encoded as a small-endian 32-bit word in the stream.
362   uint32_t insn = (bytes[3] << 24) |
363                   (bytes[2] << 16) |
364                   (bytes[1] <<  8) |
365                   (bytes[0] <<  0);
366 
367   // Calling the auto-generated decoder function.
368   DecodeStatus result = decodeARMInstruction32(MI, insn, Address, this, STI);
369   if (result != MCDisassembler::Fail) {
370     Size = 4;
371     return result;
372   }
373 
374   // VFP and NEON instructions, similarly, are shared between ARM
375   // and Thumb modes.
376   MI.clear();
377   result = decodeVFPInstruction32(MI, insn, Address, this, STI);
378   if (result != MCDisassembler::Fail) {
379     Size = 4;
380     return result;
381   }
382 
383   MI.clear();
384   result = decodeNEONDataInstruction32(MI, insn, Address, this, STI);
385   if (result != MCDisassembler::Fail) {
386     Size = 4;
387     // Add a fake predicate operand, because we share these instruction
388     // definitions with Thumb2 where these instructions are predicable.
389     if (!DecodePredicateOperand(MI, 0xE, Address, this))
390       return MCDisassembler::Fail;
391     return result;
392   }
393 
394   MI.clear();
395   result = decodeNEONLoadStoreInstruction32(MI, insn, Address, this, STI);
396   if (result != MCDisassembler::Fail) {
397     Size = 4;
398     // Add a fake predicate operand, because we share these instruction
399     // definitions with Thumb2 where these instructions are predicable.
400     if (!DecodePredicateOperand(MI, 0xE, Address, this))
401       return MCDisassembler::Fail;
402     return result;
403   }
404 
405   MI.clear();
406   result = decodeNEONDupInstruction32(MI, insn, Address, this, STI);
407   if (result != MCDisassembler::Fail) {
408     Size = 4;
409     // Add a fake predicate operand, because we share these instruction
410     // definitions with Thumb2 where these instructions are predicable.
411     if (!DecodePredicateOperand(MI, 0xE, Address, this))
412       return MCDisassembler::Fail;
413     return result;
414   }
415 
416   MI.clear();
417 
418   Size = 0;
419   return MCDisassembler::Fail;
420 }
421 
422 namespace llvm {
423 extern const MCInstrDesc ARMInsts[];
424 }
425 
426 /// tryAddingSymbolicOperand - trys to add a symbolic operand in place of the
427 /// immediate Value in the MCInst.  The immediate Value has had any PC
428 /// adjustment made by the caller.  If the instruction is a branch instruction
429 /// then isBranch is true, else false.  If the getOpInfo() function was set as
430 /// part of the setupForSymbolicDisassembly() call then that function is called
431 /// to get any symbolic information at the Address for this instruction.  If
432 /// that returns non-zero then the symbolic information it returns is used to
433 /// create an MCExpr and that is added as an operand to the MCInst.  If
434 /// getOpInfo() returns zero and isBranch is true then a symbol look up for
435 /// Value is done and if a symbol is found an MCExpr is created with that, else
436 /// an MCExpr with Value is created.  This function returns true if it adds an
437 /// operand to the MCInst and false otherwise.
438 static bool tryAddingSymbolicOperand(uint64_t Address, int32_t Value,
439                                      bool isBranch, uint64_t InstSize,
440                                      MCInst &MI, const void *Decoder) {
441   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
442   LLVMOpInfoCallback getOpInfo = Dis->getLLVMOpInfoCallback();
443   if (!getOpInfo)
444     return false;
445 
446   struct LLVMOpInfo1 SymbolicOp;
447   SymbolicOp.Value = Value;
448   void *DisInfo = Dis->getDisInfoBlock();
449   if (!getOpInfo(DisInfo, Address, 0 /* Offset */, InstSize, 1, &SymbolicOp)) {
450     if (isBranch) {
451       LLVMSymbolLookupCallback SymbolLookUp =
452                                             Dis->getLLVMSymbolLookupCallback();
453       if (SymbolLookUp) {
454         uint64_t ReferenceType;
455         ReferenceType = LLVMDisassembler_ReferenceType_In_Branch;
456         const char *ReferenceName;
457         const char *Name = SymbolLookUp(DisInfo, Value, &ReferenceType, Address,
458                                         &ReferenceName);
459         if (Name) {
460           SymbolicOp.AddSymbol.Name = Name;
461           SymbolicOp.AddSymbol.Present = true;
462           SymbolicOp.Value = 0;
463         }
464         else {
465           SymbolicOp.Value = Value;
466         }
467         if(ReferenceType == LLVMDisassembler_ReferenceType_Out_SymbolStub)
468           (*Dis->CommentStream) << "symbol stub for: " << ReferenceName;
469       }
470       else {
471         return false;
472       }
473     }
474     else {
475       return false;
476     }
477   }
478 
479   MCContext *Ctx = Dis->getMCContext();
480   const MCExpr *Add = NULL;
481   if (SymbolicOp.AddSymbol.Present) {
482     if (SymbolicOp.AddSymbol.Name) {
483       StringRef Name(SymbolicOp.AddSymbol.Name);
484       MCSymbol *Sym = Ctx->GetOrCreateSymbol(Name);
485       Add = MCSymbolRefExpr::Create(Sym, *Ctx);
486     } else {
487       Add = MCConstantExpr::Create(SymbolicOp.AddSymbol.Value, *Ctx);
488     }
489   }
490 
491   const MCExpr *Sub = NULL;
492   if (SymbolicOp.SubtractSymbol.Present) {
493     if (SymbolicOp.SubtractSymbol.Name) {
494       StringRef Name(SymbolicOp.SubtractSymbol.Name);
495       MCSymbol *Sym = Ctx->GetOrCreateSymbol(Name);
496       Sub = MCSymbolRefExpr::Create(Sym, *Ctx);
497     } else {
498       Sub = MCConstantExpr::Create(SymbolicOp.SubtractSymbol.Value, *Ctx);
499     }
500   }
501 
502   const MCExpr *Off = NULL;
503   if (SymbolicOp.Value != 0)
504     Off = MCConstantExpr::Create(SymbolicOp.Value, *Ctx);
505 
506   const MCExpr *Expr;
507   if (Sub) {
508     const MCExpr *LHS;
509     if (Add)
510       LHS = MCBinaryExpr::CreateSub(Add, Sub, *Ctx);
511     else
512       LHS = MCUnaryExpr::CreateMinus(Sub, *Ctx);
513     if (Off != 0)
514       Expr = MCBinaryExpr::CreateAdd(LHS, Off, *Ctx);
515     else
516       Expr = LHS;
517   } else if (Add) {
518     if (Off != 0)
519       Expr = MCBinaryExpr::CreateAdd(Add, Off, *Ctx);
520     else
521       Expr = Add;
522   } else {
523     if (Off != 0)
524       Expr = Off;
525     else
526       Expr = MCConstantExpr::Create(0, *Ctx);
527   }
528 
529   if (SymbolicOp.VariantKind == LLVMDisassembler_VariantKind_ARM_HI16)
530     MI.addOperand(MCOperand::CreateExpr(ARMMCExpr::CreateUpper16(Expr, *Ctx)));
531   else if (SymbolicOp.VariantKind == LLVMDisassembler_VariantKind_ARM_LO16)
532     MI.addOperand(MCOperand::CreateExpr(ARMMCExpr::CreateLower16(Expr, *Ctx)));
533   else if (SymbolicOp.VariantKind == LLVMDisassembler_VariantKind_None)
534     MI.addOperand(MCOperand::CreateExpr(Expr));
535   else
536     assert(0 && "bad SymbolicOp.VariantKind");
537 
538   return true;
539 }
540 
541 /// tryAddingPcLoadReferenceComment - trys to add a comment as to what is being
542 /// referenced by a load instruction with the base register that is the Pc.
543 /// These can often be values in a literal pool near the Address of the
544 /// instruction.  The Address of the instruction and its immediate Value are
545 /// used as a possible literal pool entry.  The SymbolLookUp call back will
546 /// return the name of a symbol referenced by the the literal pool's entry if
547 /// the referenced address is that of a symbol.  Or it will return a pointer to
548 /// a literal 'C' string if the referenced address of the literal pool's entry
549 /// is an address into a section with 'C' string literals.
550 static void tryAddingPcLoadReferenceComment(uint64_t Address, int Value,
551 					    const void *Decoder) {
552   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
553   LLVMSymbolLookupCallback SymbolLookUp = Dis->getLLVMSymbolLookupCallback();
554   if (SymbolLookUp) {
555     void *DisInfo = Dis->getDisInfoBlock();
556     uint64_t ReferenceType;
557     ReferenceType = LLVMDisassembler_ReferenceType_In_PCrel_Load;
558     const char *ReferenceName;
559     (void)SymbolLookUp(DisInfo, Value, &ReferenceType, Address, &ReferenceName);
560     if(ReferenceType == LLVMDisassembler_ReferenceType_Out_LitPool_SymAddr ||
561        ReferenceType == LLVMDisassembler_ReferenceType_Out_LitPool_CstrAddr)
562       (*Dis->CommentStream) << "literal pool for: " << ReferenceName;
563   }
564 }
565 
566 // Thumb1 instructions don't have explicit S bits.  Rather, they
567 // implicitly set CPSR.  Since it's not represented in the encoding, the
568 // auto-generated decoder won't inject the CPSR operand.  We need to fix
569 // that as a post-pass.
570 static void AddThumb1SBit(MCInst &MI, bool InITBlock) {
571   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
572   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
573   MCInst::iterator I = MI.begin();
574   for (unsigned i = 0; i < NumOps; ++i, ++I) {
575     if (I == MI.end()) break;
576     if (OpInfo[i].isOptionalDef() && OpInfo[i].RegClass == ARM::CCRRegClassID) {
577       if (i > 0 && OpInfo[i-1].isPredicate()) continue;
578       MI.insert(I, MCOperand::CreateReg(InITBlock ? 0 : ARM::CPSR));
579       return;
580     }
581   }
582 
583   MI.insert(I, MCOperand::CreateReg(InITBlock ? 0 : ARM::CPSR));
584 }
585 
586 // Most Thumb instructions don't have explicit predicates in the
587 // encoding, but rather get their predicates from IT context.  We need
588 // to fix up the predicate operands using this context information as a
589 // post-pass.
590 MCDisassembler::DecodeStatus
591 ThumbDisassembler::AddThumbPredicate(MCInst &MI) const {
592   MCDisassembler::DecodeStatus S = Success;
593 
594   // A few instructions actually have predicates encoded in them.  Don't
595   // try to overwrite it if we're seeing one of those.
596   switch (MI.getOpcode()) {
597     case ARM::tBcc:
598     case ARM::t2Bcc:
599     case ARM::tCBZ:
600     case ARM::tCBNZ:
601     case ARM::tCPS:
602     case ARM::t2CPS3p:
603     case ARM::t2CPS2p:
604     case ARM::t2CPS1p:
605     case ARM::tMOVSr:
606     case ARM::tSETEND:
607       // Some instructions (mostly conditional branches) are not
608       // allowed in IT blocks.
609       if (!ITBlock.empty())
610         S = SoftFail;
611       else
612         return Success;
613       break;
614     case ARM::tB:
615     case ARM::t2B:
616     case ARM::t2TBB:
617     case ARM::t2TBH:
618       // Some instructions (mostly unconditional branches) can
619       // only appears at the end of, or outside of, an IT.
620       if (ITBlock.size() > 1)
621         S = SoftFail;
622       break;
623     default:
624       break;
625   }
626 
627   // If we're in an IT block, base the predicate on that.  Otherwise,
628   // assume a predicate of AL.
629   unsigned CC;
630   if (!ITBlock.empty()) {
631     CC = ITBlock.back();
632     if (CC == 0xF)
633       CC = ARMCC::AL;
634     ITBlock.pop_back();
635   } else
636     CC = ARMCC::AL;
637 
638   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
639   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
640   MCInst::iterator I = MI.begin();
641   for (unsigned i = 0; i < NumOps; ++i, ++I) {
642     if (I == MI.end()) break;
643     if (OpInfo[i].isPredicate()) {
644       I = MI.insert(I, MCOperand::CreateImm(CC));
645       ++I;
646       if (CC == ARMCC::AL)
647         MI.insert(I, MCOperand::CreateReg(0));
648       else
649         MI.insert(I, MCOperand::CreateReg(ARM::CPSR));
650       return S;
651     }
652   }
653 
654   I = MI.insert(I, MCOperand::CreateImm(CC));
655   ++I;
656   if (CC == ARMCC::AL)
657     MI.insert(I, MCOperand::CreateReg(0));
658   else
659     MI.insert(I, MCOperand::CreateReg(ARM::CPSR));
660 
661   return S;
662 }
663 
664 // Thumb VFP instructions are a special case.  Because we share their
665 // encodings between ARM and Thumb modes, and they are predicable in ARM
666 // mode, the auto-generated decoder will give them an (incorrect)
667 // predicate operand.  We need to rewrite these operands based on the IT
668 // context as a post-pass.
669 void ThumbDisassembler::UpdateThumbVFPPredicate(MCInst &MI) const {
670   unsigned CC;
671   if (!ITBlock.empty()) {
672     CC = ITBlock.back();
673     ITBlock.pop_back();
674   } else
675     CC = ARMCC::AL;
676 
677   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
678   MCInst::iterator I = MI.begin();
679   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
680   for (unsigned i = 0; i < NumOps; ++i, ++I) {
681     if (OpInfo[i].isPredicate() ) {
682       I->setImm(CC);
683       ++I;
684       if (CC == ARMCC::AL)
685         I->setReg(0);
686       else
687         I->setReg(ARM::CPSR);
688       return;
689     }
690   }
691 }
692 
693 DecodeStatus ThumbDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
694                                                const MemoryObject &Region,
695                                                uint64_t Address,
696                                                raw_ostream &os,
697                                                raw_ostream &cs) const {
698   CommentStream = &cs;
699 
700   uint8_t bytes[4];
701 
702   assert((STI.getFeatureBits() & ARM::ModeThumb) &&
703          "Asked to disassemble in Thumb mode but Subtarget is in ARM mode!");
704 
705   // We want to read exactly 2 bytes of data.
706   if (Region.readBytes(Address, 2, (uint8_t*)bytes, NULL) == -1) {
707     Size = 0;
708     return MCDisassembler::Fail;
709   }
710 
711   uint16_t insn16 = (bytes[1] << 8) | bytes[0];
712   DecodeStatus result = decodeThumbInstruction16(MI, insn16, Address, this, STI);
713   if (result != MCDisassembler::Fail) {
714     Size = 2;
715     Check(result, AddThumbPredicate(MI));
716     return result;
717   }
718 
719   MI.clear();
720   result = decodeThumbSBitInstruction16(MI, insn16, Address, this, STI);
721   if (result) {
722     Size = 2;
723     bool InITBlock = !ITBlock.empty();
724     Check(result, AddThumbPredicate(MI));
725     AddThumb1SBit(MI, InITBlock);
726     return result;
727   }
728 
729   MI.clear();
730   result = decodeThumb2Instruction16(MI, insn16, Address, this, STI);
731   if (result != MCDisassembler::Fail) {
732     Size = 2;
733 
734     // Nested IT blocks are UNPREDICTABLE.  Must be checked before we add
735     // the Thumb predicate.
736     if (MI.getOpcode() == ARM::t2IT && !ITBlock.empty())
737       result = MCDisassembler::SoftFail;
738 
739     Check(result, AddThumbPredicate(MI));
740 
741     // If we find an IT instruction, we need to parse its condition
742     // code and mask operands so that we can apply them correctly
743     // to the subsequent instructions.
744     if (MI.getOpcode() == ARM::t2IT) {
745 
746       // (3 - the number of trailing zeros) is the number of then / else.
747       unsigned firstcond = MI.getOperand(0).getImm();
748       unsigned Mask = MI.getOperand(1).getImm();
749       unsigned CondBit0 = Mask >> 4 & 1;
750       unsigned NumTZ = CountTrailingZeros_32(Mask);
751       assert(NumTZ <= 3 && "Invalid IT mask!");
752       for (unsigned Pos = 3, e = NumTZ; Pos > e; --Pos) {
753         bool T = ((Mask >> Pos) & 1) == CondBit0;
754         if (T)
755           ITBlock.insert(ITBlock.begin(), firstcond);
756         else
757           ITBlock.insert(ITBlock.begin(), firstcond ^ 1);
758       }
759 
760       ITBlock.push_back(firstcond);
761     }
762 
763     return result;
764   }
765 
766   // We want to read exactly 4 bytes of data.
767   if (Region.readBytes(Address, 4, (uint8_t*)bytes, NULL) == -1) {
768     Size = 0;
769     return MCDisassembler::Fail;
770   }
771 
772   uint32_t insn32 = (bytes[3] <<  8) |
773                     (bytes[2] <<  0) |
774                     (bytes[1] << 24) |
775                     (bytes[0] << 16);
776   MI.clear();
777   result = decodeThumbInstruction32(MI, insn32, Address, this, STI);
778   if (result != MCDisassembler::Fail) {
779     Size = 4;
780     bool InITBlock = ITBlock.size();
781     Check(result, AddThumbPredicate(MI));
782     AddThumb1SBit(MI, InITBlock);
783     return result;
784   }
785 
786   MI.clear();
787   result = decodeThumb2Instruction32(MI, insn32, Address, this, STI);
788   if (result != MCDisassembler::Fail) {
789     Size = 4;
790     Check(result, AddThumbPredicate(MI));
791     return result;
792   }
793 
794   MI.clear();
795   result = decodeVFPInstruction32(MI, insn32, Address, this, STI);
796   if (result != MCDisassembler::Fail) {
797     Size = 4;
798     UpdateThumbVFPPredicate(MI);
799     return result;
800   }
801 
802   MI.clear();
803   result = decodeNEONDupInstruction32(MI, insn32, Address, this, STI);
804   if (result != MCDisassembler::Fail) {
805     Size = 4;
806     Check(result, AddThumbPredicate(MI));
807     return result;
808   }
809 
810   if (fieldFromInstruction32(insn32, 24, 8) == 0xF9) {
811     MI.clear();
812     uint32_t NEONLdStInsn = insn32;
813     NEONLdStInsn &= 0xF0FFFFFF;
814     NEONLdStInsn |= 0x04000000;
815     result = decodeNEONLoadStoreInstruction32(MI, NEONLdStInsn, Address, this, STI);
816     if (result != MCDisassembler::Fail) {
817       Size = 4;
818       Check(result, AddThumbPredicate(MI));
819       return result;
820     }
821   }
822 
823   if (fieldFromInstruction32(insn32, 24, 4) == 0xF) {
824     MI.clear();
825     uint32_t NEONDataInsn = insn32;
826     NEONDataInsn &= 0xF0FFFFFF; // Clear bits 27-24
827     NEONDataInsn |= (NEONDataInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
828     NEONDataInsn |= 0x12000000; // Set bits 28 and 25
829     result = decodeNEONDataInstruction32(MI, NEONDataInsn, Address, this, STI);
830     if (result != MCDisassembler::Fail) {
831       Size = 4;
832       Check(result, AddThumbPredicate(MI));
833       return result;
834     }
835   }
836 
837   Size = 0;
838   return MCDisassembler::Fail;
839 }
840 
841 
842 extern "C" void LLVMInitializeARMDisassembler() {
843   TargetRegistry::RegisterMCDisassembler(TheARMTarget,
844                                          createARMDisassembler);
845   TargetRegistry::RegisterMCDisassembler(TheThumbTarget,
846                                          createThumbDisassembler);
847 }
848 
849 static const unsigned GPRDecoderTable[] = {
850   ARM::R0, ARM::R1, ARM::R2, ARM::R3,
851   ARM::R4, ARM::R5, ARM::R6, ARM::R7,
852   ARM::R8, ARM::R9, ARM::R10, ARM::R11,
853   ARM::R12, ARM::SP, ARM::LR, ARM::PC
854 };
855 
856 static DecodeStatus DecodeGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
857                                    uint64_t Address, const void *Decoder) {
858   if (RegNo > 15)
859     return MCDisassembler::Fail;
860 
861   unsigned Register = GPRDecoderTable[RegNo];
862   Inst.addOperand(MCOperand::CreateReg(Register));
863   return MCDisassembler::Success;
864 }
865 
866 static DecodeStatus
867 DecodeGPRnopcRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
868                            uint64_t Address, const void *Decoder) {
869   if (RegNo == 15) return MCDisassembler::Fail;
870   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
871 }
872 
873 static DecodeStatus DecodetGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
874                                    uint64_t Address, const void *Decoder) {
875   if (RegNo > 7)
876     return MCDisassembler::Fail;
877   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
878 }
879 
880 static DecodeStatus DecodetcGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
881                                    uint64_t Address, const void *Decoder) {
882   unsigned Register = 0;
883   switch (RegNo) {
884     case 0:
885       Register = ARM::R0;
886       break;
887     case 1:
888       Register = ARM::R1;
889       break;
890     case 2:
891       Register = ARM::R2;
892       break;
893     case 3:
894       Register = ARM::R3;
895       break;
896     case 9:
897       Register = ARM::R9;
898       break;
899     case 12:
900       Register = ARM::R12;
901       break;
902     default:
903       return MCDisassembler::Fail;
904     }
905 
906   Inst.addOperand(MCOperand::CreateReg(Register));
907   return MCDisassembler::Success;
908 }
909 
910 static DecodeStatus DecoderGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
911                                    uint64_t Address, const void *Decoder) {
912   if (RegNo == 13 || RegNo == 15) return MCDisassembler::Fail;
913   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
914 }
915 
916 static const unsigned SPRDecoderTable[] = {
917      ARM::S0,  ARM::S1,  ARM::S2,  ARM::S3,
918      ARM::S4,  ARM::S5,  ARM::S6,  ARM::S7,
919      ARM::S8,  ARM::S9, ARM::S10, ARM::S11,
920     ARM::S12, ARM::S13, ARM::S14, ARM::S15,
921     ARM::S16, ARM::S17, ARM::S18, ARM::S19,
922     ARM::S20, ARM::S21, ARM::S22, ARM::S23,
923     ARM::S24, ARM::S25, ARM::S26, ARM::S27,
924     ARM::S28, ARM::S29, ARM::S30, ARM::S31
925 };
926 
927 static DecodeStatus DecodeSPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
928                                    uint64_t Address, const void *Decoder) {
929   if (RegNo > 31)
930     return MCDisassembler::Fail;
931 
932   unsigned Register = SPRDecoderTable[RegNo];
933   Inst.addOperand(MCOperand::CreateReg(Register));
934   return MCDisassembler::Success;
935 }
936 
937 static const unsigned DPRDecoderTable[] = {
938      ARM::D0,  ARM::D1,  ARM::D2,  ARM::D3,
939      ARM::D4,  ARM::D5,  ARM::D6,  ARM::D7,
940      ARM::D8,  ARM::D9, ARM::D10, ARM::D11,
941     ARM::D12, ARM::D13, ARM::D14, ARM::D15,
942     ARM::D16, ARM::D17, ARM::D18, ARM::D19,
943     ARM::D20, ARM::D21, ARM::D22, ARM::D23,
944     ARM::D24, ARM::D25, ARM::D26, ARM::D27,
945     ARM::D28, ARM::D29, ARM::D30, ARM::D31
946 };
947 
948 static DecodeStatus DecodeDPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
949                                    uint64_t Address, const void *Decoder) {
950   if (RegNo > 31)
951     return MCDisassembler::Fail;
952 
953   unsigned Register = DPRDecoderTable[RegNo];
954   Inst.addOperand(MCOperand::CreateReg(Register));
955   return MCDisassembler::Success;
956 }
957 
958 static DecodeStatus DecodeDPR_8RegisterClass(llvm::MCInst &Inst, unsigned RegNo,
959                                    uint64_t Address, const void *Decoder) {
960   if (RegNo > 7)
961     return MCDisassembler::Fail;
962   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
963 }
964 
965 static DecodeStatus
966 DecodeDPR_VFP2RegisterClass(llvm::MCInst &Inst, unsigned RegNo,
967                             uint64_t Address, const void *Decoder) {
968   if (RegNo > 15)
969     return MCDisassembler::Fail;
970   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
971 }
972 
973 static const unsigned QPRDecoderTable[] = {
974      ARM::Q0,  ARM::Q1,  ARM::Q2,  ARM::Q3,
975      ARM::Q4,  ARM::Q5,  ARM::Q6,  ARM::Q7,
976      ARM::Q8,  ARM::Q9, ARM::Q10, ARM::Q11,
977     ARM::Q12, ARM::Q13, ARM::Q14, ARM::Q15
978 };
979 
980 
981 static DecodeStatus DecodeQPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
982                                    uint64_t Address, const void *Decoder) {
983   if (RegNo > 31)
984     return MCDisassembler::Fail;
985   RegNo >>= 1;
986 
987   unsigned Register = QPRDecoderTable[RegNo];
988   Inst.addOperand(MCOperand::CreateReg(Register));
989   return MCDisassembler::Success;
990 }
991 
992 static DecodeStatus DecodePredicateOperand(llvm::MCInst &Inst, unsigned Val,
993                                uint64_t Address, const void *Decoder) {
994   if (Val == 0xF) return MCDisassembler::Fail;
995   // AL predicate is not allowed on Thumb1 branches.
996   if (Inst.getOpcode() == ARM::tBcc && Val == 0xE)
997     return MCDisassembler::Fail;
998   Inst.addOperand(MCOperand::CreateImm(Val));
999   if (Val == ARMCC::AL) {
1000     Inst.addOperand(MCOperand::CreateReg(0));
1001   } else
1002     Inst.addOperand(MCOperand::CreateReg(ARM::CPSR));
1003   return MCDisassembler::Success;
1004 }
1005 
1006 static DecodeStatus DecodeCCOutOperand(llvm::MCInst &Inst, unsigned Val,
1007                                uint64_t Address, const void *Decoder) {
1008   if (Val)
1009     Inst.addOperand(MCOperand::CreateReg(ARM::CPSR));
1010   else
1011     Inst.addOperand(MCOperand::CreateReg(0));
1012   return MCDisassembler::Success;
1013 }
1014 
1015 static DecodeStatus DecodeSOImmOperand(llvm::MCInst &Inst, unsigned Val,
1016                                uint64_t Address, const void *Decoder) {
1017   uint32_t imm = Val & 0xFF;
1018   uint32_t rot = (Val & 0xF00) >> 7;
1019   uint32_t rot_imm = (imm >> rot) | (imm << ((32-rot) & 0x1F));
1020   Inst.addOperand(MCOperand::CreateImm(rot_imm));
1021   return MCDisassembler::Success;
1022 }
1023 
1024 static DecodeStatus DecodeSORegImmOperand(llvm::MCInst &Inst, unsigned Val,
1025                                uint64_t Address, const void *Decoder) {
1026   DecodeStatus S = MCDisassembler::Success;
1027 
1028   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
1029   unsigned type = fieldFromInstruction32(Val, 5, 2);
1030   unsigned imm = fieldFromInstruction32(Val, 7, 5);
1031 
1032   // Register-immediate
1033   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1034     return MCDisassembler::Fail;
1035 
1036   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
1037   switch (type) {
1038     case 0:
1039       Shift = ARM_AM::lsl;
1040       break;
1041     case 1:
1042       Shift = ARM_AM::lsr;
1043       break;
1044     case 2:
1045       Shift = ARM_AM::asr;
1046       break;
1047     case 3:
1048       Shift = ARM_AM::ror;
1049       break;
1050   }
1051 
1052   if (Shift == ARM_AM::ror && imm == 0)
1053     Shift = ARM_AM::rrx;
1054 
1055   unsigned Op = Shift | (imm << 3);
1056   Inst.addOperand(MCOperand::CreateImm(Op));
1057 
1058   return S;
1059 }
1060 
1061 static DecodeStatus DecodeSORegRegOperand(llvm::MCInst &Inst, unsigned Val,
1062                                uint64_t Address, const void *Decoder) {
1063   DecodeStatus S = MCDisassembler::Success;
1064 
1065   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
1066   unsigned type = fieldFromInstruction32(Val, 5, 2);
1067   unsigned Rs = fieldFromInstruction32(Val, 8, 4);
1068 
1069   // Register-register
1070   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1071     return MCDisassembler::Fail;
1072   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rs, Address, Decoder)))
1073     return MCDisassembler::Fail;
1074 
1075   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
1076   switch (type) {
1077     case 0:
1078       Shift = ARM_AM::lsl;
1079       break;
1080     case 1:
1081       Shift = ARM_AM::lsr;
1082       break;
1083     case 2:
1084       Shift = ARM_AM::asr;
1085       break;
1086     case 3:
1087       Shift = ARM_AM::ror;
1088       break;
1089   }
1090 
1091   Inst.addOperand(MCOperand::CreateImm(Shift));
1092 
1093   return S;
1094 }
1095 
1096 static DecodeStatus DecodeRegListOperand(llvm::MCInst &Inst, unsigned Val,
1097                                  uint64_t Address, const void *Decoder) {
1098   DecodeStatus S = MCDisassembler::Success;
1099 
1100   bool writebackLoad = false;
1101   unsigned writebackReg = 0;
1102   switch (Inst.getOpcode()) {
1103     default:
1104       break;
1105     case ARM::LDMIA_UPD:
1106     case ARM::LDMDB_UPD:
1107     case ARM::LDMIB_UPD:
1108     case ARM::LDMDA_UPD:
1109     case ARM::t2LDMIA_UPD:
1110     case ARM::t2LDMDB_UPD:
1111       writebackLoad = true;
1112       writebackReg = Inst.getOperand(0).getReg();
1113       break;
1114   }
1115 
1116   // Empty register lists are not allowed.
1117   if (CountPopulation_32(Val) == 0) return MCDisassembler::Fail;
1118   for (unsigned i = 0; i < 16; ++i) {
1119     if (Val & (1 << i)) {
1120       if (!Check(S, DecodeGPRRegisterClass(Inst, i, Address, Decoder)))
1121         return MCDisassembler::Fail;
1122       // Writeback not allowed if Rn is in the target list.
1123       if (writebackLoad && writebackReg == Inst.end()[-1].getReg())
1124         Check(S, MCDisassembler::SoftFail);
1125     }
1126   }
1127 
1128   return S;
1129 }
1130 
1131 static DecodeStatus DecodeSPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
1132                                  uint64_t Address, const void *Decoder) {
1133   DecodeStatus S = MCDisassembler::Success;
1134 
1135   unsigned Vd = fieldFromInstruction32(Val, 8, 4);
1136   unsigned regs = Val & 0xFF;
1137 
1138   if (!Check(S, DecodeSPRRegisterClass(Inst, Vd, Address, Decoder)))
1139     return MCDisassembler::Fail;
1140   for (unsigned i = 0; i < (regs - 1); ++i) {
1141     if (!Check(S, DecodeSPRRegisterClass(Inst, ++Vd, Address, Decoder)))
1142       return MCDisassembler::Fail;
1143   }
1144 
1145   return S;
1146 }
1147 
1148 static DecodeStatus DecodeDPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
1149                                  uint64_t Address, const void *Decoder) {
1150   DecodeStatus S = MCDisassembler::Success;
1151 
1152   unsigned Vd = fieldFromInstruction32(Val, 8, 4);
1153   unsigned regs = (Val & 0xFF) / 2;
1154 
1155   if (!Check(S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)))
1156       return MCDisassembler::Fail;
1157   for (unsigned i = 0; i < (regs - 1); ++i) {
1158     if (!Check(S, DecodeDPRRegisterClass(Inst, ++Vd, Address, Decoder)))
1159       return MCDisassembler::Fail;
1160   }
1161 
1162   return S;
1163 }
1164 
1165 static DecodeStatus DecodeBitfieldMaskOperand(llvm::MCInst &Inst, unsigned Val,
1166                                       uint64_t Address, const void *Decoder) {
1167   // This operand encodes a mask of contiguous zeros between a specified MSB
1168   // and LSB.  To decode it, we create the mask of all bits MSB-and-lower,
1169   // the mask of all bits LSB-and-lower, and then xor them to create
1170   // the mask of that's all ones on [msb, lsb].  Finally we not it to
1171   // create the final mask.
1172   unsigned msb = fieldFromInstruction32(Val, 5, 5);
1173   unsigned lsb = fieldFromInstruction32(Val, 0, 5);
1174 
1175   DecodeStatus S = MCDisassembler::Success;
1176   if (lsb > msb) Check(S, MCDisassembler::SoftFail);
1177 
1178   uint32_t msb_mask = 0xFFFFFFFF;
1179   if (msb != 31) msb_mask = (1U << (msb+1)) - 1;
1180   uint32_t lsb_mask = (1U << lsb) - 1;
1181 
1182   Inst.addOperand(MCOperand::CreateImm(~(msb_mask ^ lsb_mask)));
1183   return S;
1184 }
1185 
1186 static DecodeStatus DecodeCopMemInstruction(llvm::MCInst &Inst, unsigned Insn,
1187                                   uint64_t Address, const void *Decoder) {
1188   DecodeStatus S = MCDisassembler::Success;
1189 
1190   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1191   unsigned CRd = fieldFromInstruction32(Insn, 12, 4);
1192   unsigned coproc = fieldFromInstruction32(Insn, 8, 4);
1193   unsigned imm = fieldFromInstruction32(Insn, 0, 8);
1194   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1195   unsigned U = fieldFromInstruction32(Insn, 23, 1);
1196 
1197   switch (Inst.getOpcode()) {
1198     case ARM::LDC_OFFSET:
1199     case ARM::LDC_PRE:
1200     case ARM::LDC_POST:
1201     case ARM::LDC_OPTION:
1202     case ARM::LDCL_OFFSET:
1203     case ARM::LDCL_PRE:
1204     case ARM::LDCL_POST:
1205     case ARM::LDCL_OPTION:
1206     case ARM::STC_OFFSET:
1207     case ARM::STC_PRE:
1208     case ARM::STC_POST:
1209     case ARM::STC_OPTION:
1210     case ARM::STCL_OFFSET:
1211     case ARM::STCL_PRE:
1212     case ARM::STCL_POST:
1213     case ARM::STCL_OPTION:
1214     case ARM::t2LDC_OFFSET:
1215     case ARM::t2LDC_PRE:
1216     case ARM::t2LDC_POST:
1217     case ARM::t2LDC_OPTION:
1218     case ARM::t2LDCL_OFFSET:
1219     case ARM::t2LDCL_PRE:
1220     case ARM::t2LDCL_POST:
1221     case ARM::t2LDCL_OPTION:
1222     case ARM::t2STC_OFFSET:
1223     case ARM::t2STC_PRE:
1224     case ARM::t2STC_POST:
1225     case ARM::t2STC_OPTION:
1226     case ARM::t2STCL_OFFSET:
1227     case ARM::t2STCL_PRE:
1228     case ARM::t2STCL_POST:
1229     case ARM::t2STCL_OPTION:
1230       if (coproc == 0xA || coproc == 0xB)
1231         return MCDisassembler::Fail;
1232       break;
1233     default:
1234       break;
1235   }
1236 
1237   Inst.addOperand(MCOperand::CreateImm(coproc));
1238   Inst.addOperand(MCOperand::CreateImm(CRd));
1239   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1240     return MCDisassembler::Fail;
1241 
1242   switch (Inst.getOpcode()) {
1243     case ARM::t2LDC2_OFFSET:
1244     case ARM::t2LDC2L_OFFSET:
1245     case ARM::t2LDC2_PRE:
1246     case ARM::t2LDC2L_PRE:
1247     case ARM::t2STC2_OFFSET:
1248     case ARM::t2STC2L_OFFSET:
1249     case ARM::t2STC2_PRE:
1250     case ARM::t2STC2L_PRE:
1251     case ARM::LDC2_OFFSET:
1252     case ARM::LDC2L_OFFSET:
1253     case ARM::LDC2_PRE:
1254     case ARM::LDC2L_PRE:
1255     case ARM::STC2_OFFSET:
1256     case ARM::STC2L_OFFSET:
1257     case ARM::STC2_PRE:
1258     case ARM::STC2L_PRE:
1259     case ARM::t2LDC_OFFSET:
1260     case ARM::t2LDCL_OFFSET:
1261     case ARM::t2LDC_PRE:
1262     case ARM::t2LDCL_PRE:
1263     case ARM::t2STC_OFFSET:
1264     case ARM::t2STCL_OFFSET:
1265     case ARM::t2STC_PRE:
1266     case ARM::t2STCL_PRE:
1267     case ARM::LDC_OFFSET:
1268     case ARM::LDCL_OFFSET:
1269     case ARM::LDC_PRE:
1270     case ARM::LDCL_PRE:
1271     case ARM::STC_OFFSET:
1272     case ARM::STCL_OFFSET:
1273     case ARM::STC_PRE:
1274     case ARM::STCL_PRE:
1275       imm = ARM_AM::getAM5Opc(U ? ARM_AM::add : ARM_AM::sub, imm);
1276       Inst.addOperand(MCOperand::CreateImm(imm));
1277       break;
1278     case ARM::t2LDC2_POST:
1279     case ARM::t2LDC2L_POST:
1280     case ARM::t2STC2_POST:
1281     case ARM::t2STC2L_POST:
1282     case ARM::LDC2_POST:
1283     case ARM::LDC2L_POST:
1284     case ARM::STC2_POST:
1285     case ARM::STC2L_POST:
1286     case ARM::t2LDC_POST:
1287     case ARM::t2LDCL_POST:
1288     case ARM::t2STC_POST:
1289     case ARM::t2STCL_POST:
1290     case ARM::LDC_POST:
1291     case ARM::LDCL_POST:
1292     case ARM::STC_POST:
1293     case ARM::STCL_POST:
1294       imm |= U << 8;
1295       // fall through.
1296     default:
1297       // The 'option' variant doesn't encode 'U' in the immediate since
1298       // the immediate is unsigned [0,255].
1299       Inst.addOperand(MCOperand::CreateImm(imm));
1300       break;
1301   }
1302 
1303   switch (Inst.getOpcode()) {
1304     case ARM::LDC_OFFSET:
1305     case ARM::LDC_PRE:
1306     case ARM::LDC_POST:
1307     case ARM::LDC_OPTION:
1308     case ARM::LDCL_OFFSET:
1309     case ARM::LDCL_PRE:
1310     case ARM::LDCL_POST:
1311     case ARM::LDCL_OPTION:
1312     case ARM::STC_OFFSET:
1313     case ARM::STC_PRE:
1314     case ARM::STC_POST:
1315     case ARM::STC_OPTION:
1316     case ARM::STCL_OFFSET:
1317     case ARM::STCL_PRE:
1318     case ARM::STCL_POST:
1319     case ARM::STCL_OPTION:
1320       if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1321         return MCDisassembler::Fail;
1322       break;
1323     default:
1324       break;
1325   }
1326 
1327   return S;
1328 }
1329 
1330 static DecodeStatus
1331 DecodeAddrMode2IdxInstruction(llvm::MCInst &Inst, unsigned Insn,
1332                               uint64_t Address, const void *Decoder) {
1333   DecodeStatus S = MCDisassembler::Success;
1334 
1335   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1336   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
1337   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1338   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
1339   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1340   unsigned reg = fieldFromInstruction32(Insn, 25, 1);
1341   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1342   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1343 
1344   // On stores, the writeback operand precedes Rt.
1345   switch (Inst.getOpcode()) {
1346     case ARM::STR_POST_IMM:
1347     case ARM::STR_POST_REG:
1348     case ARM::STRB_POST_IMM:
1349     case ARM::STRB_POST_REG:
1350     case ARM::STRT_POST_REG:
1351     case ARM::STRT_POST_IMM:
1352     case ARM::STRBT_POST_REG:
1353     case ARM::STRBT_POST_IMM:
1354       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1355         return MCDisassembler::Fail;
1356       break;
1357     default:
1358       break;
1359   }
1360 
1361   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
1362     return MCDisassembler::Fail;
1363 
1364   // On loads, the writeback operand comes after Rt.
1365   switch (Inst.getOpcode()) {
1366     case ARM::LDR_POST_IMM:
1367     case ARM::LDR_POST_REG:
1368     case ARM::LDRB_POST_IMM:
1369     case ARM::LDRB_POST_REG:
1370     case ARM::LDRBT_POST_REG:
1371     case ARM::LDRBT_POST_IMM:
1372     case ARM::LDRT_POST_REG:
1373     case ARM::LDRT_POST_IMM:
1374       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1375         return MCDisassembler::Fail;
1376       break;
1377     default:
1378       break;
1379   }
1380 
1381   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1382     return MCDisassembler::Fail;
1383 
1384   ARM_AM::AddrOpc Op = ARM_AM::add;
1385   if (!fieldFromInstruction32(Insn, 23, 1))
1386     Op = ARM_AM::sub;
1387 
1388   bool writeback = (P == 0) || (W == 1);
1389   unsigned idx_mode = 0;
1390   if (P && writeback)
1391     idx_mode = ARMII::IndexModePre;
1392   else if (!P && writeback)
1393     idx_mode = ARMII::IndexModePost;
1394 
1395   if (writeback && (Rn == 15 || Rn == Rt))
1396     S = MCDisassembler::SoftFail; // UNPREDICTABLE
1397 
1398   if (reg) {
1399     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1400       return MCDisassembler::Fail;
1401     ARM_AM::ShiftOpc Opc = ARM_AM::lsl;
1402     switch( fieldFromInstruction32(Insn, 5, 2)) {
1403       case 0:
1404         Opc = ARM_AM::lsl;
1405         break;
1406       case 1:
1407         Opc = ARM_AM::lsr;
1408         break;
1409       case 2:
1410         Opc = ARM_AM::asr;
1411         break;
1412       case 3:
1413         Opc = ARM_AM::ror;
1414         break;
1415       default:
1416         return MCDisassembler::Fail;
1417     }
1418     unsigned amt = fieldFromInstruction32(Insn, 7, 5);
1419     unsigned imm = ARM_AM::getAM2Opc(Op, amt, Opc, idx_mode);
1420 
1421     Inst.addOperand(MCOperand::CreateImm(imm));
1422   } else {
1423     Inst.addOperand(MCOperand::CreateReg(0));
1424     unsigned tmp = ARM_AM::getAM2Opc(Op, imm, ARM_AM::lsl, idx_mode);
1425     Inst.addOperand(MCOperand::CreateImm(tmp));
1426   }
1427 
1428   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1429     return MCDisassembler::Fail;
1430 
1431   return S;
1432 }
1433 
1434 static DecodeStatus DecodeSORegMemOperand(llvm::MCInst &Inst, unsigned Val,
1435                                   uint64_t Address, const void *Decoder) {
1436   DecodeStatus S = MCDisassembler::Success;
1437 
1438   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
1439   unsigned Rm = fieldFromInstruction32(Val,  0, 4);
1440   unsigned type = fieldFromInstruction32(Val, 5, 2);
1441   unsigned imm = fieldFromInstruction32(Val, 7, 5);
1442   unsigned U = fieldFromInstruction32(Val, 12, 1);
1443 
1444   ARM_AM::ShiftOpc ShOp = ARM_AM::lsl;
1445   switch (type) {
1446     case 0:
1447       ShOp = ARM_AM::lsl;
1448       break;
1449     case 1:
1450       ShOp = ARM_AM::lsr;
1451       break;
1452     case 2:
1453       ShOp = ARM_AM::asr;
1454       break;
1455     case 3:
1456       ShOp = ARM_AM::ror;
1457       break;
1458   }
1459 
1460   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1461     return MCDisassembler::Fail;
1462   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1463     return MCDisassembler::Fail;
1464   unsigned shift;
1465   if (U)
1466     shift = ARM_AM::getAM2Opc(ARM_AM::add, imm, ShOp);
1467   else
1468     shift = ARM_AM::getAM2Opc(ARM_AM::sub, imm, ShOp);
1469   Inst.addOperand(MCOperand::CreateImm(shift));
1470 
1471   return S;
1472 }
1473 
1474 static DecodeStatus
1475 DecodeAddrMode3Instruction(llvm::MCInst &Inst, unsigned Insn,
1476                            uint64_t Address, const void *Decoder) {
1477   DecodeStatus S = MCDisassembler::Success;
1478 
1479   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
1480   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1481   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1482   unsigned type = fieldFromInstruction32(Insn, 22, 1);
1483   unsigned imm = fieldFromInstruction32(Insn, 8, 4);
1484   unsigned U = ((~fieldFromInstruction32(Insn, 23, 1)) & 1) << 8;
1485   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1486   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1487   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1488 
1489   bool writeback = (W == 1) | (P == 0);
1490 
1491   // For {LD,ST}RD, Rt must be even, else undefined.
1492   switch (Inst.getOpcode()) {
1493     case ARM::STRD:
1494     case ARM::STRD_PRE:
1495     case ARM::STRD_POST:
1496     case ARM::LDRD:
1497     case ARM::LDRD_PRE:
1498     case ARM::LDRD_POST:
1499       if (Rt & 0x1) return MCDisassembler::Fail;
1500       break;
1501     default:
1502       break;
1503   }
1504 
1505   if (writeback) { // Writeback
1506     if (P)
1507       U |= ARMII::IndexModePre << 9;
1508     else
1509       U |= ARMII::IndexModePost << 9;
1510 
1511     // On stores, the writeback operand precedes Rt.
1512     switch (Inst.getOpcode()) {
1513     case ARM::STRD:
1514     case ARM::STRD_PRE:
1515     case ARM::STRD_POST:
1516     case ARM::STRH:
1517     case ARM::STRH_PRE:
1518     case ARM::STRH_POST:
1519       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1520         return MCDisassembler::Fail;
1521       break;
1522     default:
1523       break;
1524     }
1525   }
1526 
1527   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
1528     return MCDisassembler::Fail;
1529   switch (Inst.getOpcode()) {
1530     case ARM::STRD:
1531     case ARM::STRD_PRE:
1532     case ARM::STRD_POST:
1533     case ARM::LDRD:
1534     case ARM::LDRD_PRE:
1535     case ARM::LDRD_POST:
1536       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
1537         return MCDisassembler::Fail;
1538       break;
1539     default:
1540       break;
1541   }
1542 
1543   if (writeback) {
1544     // On loads, the writeback operand comes after Rt.
1545     switch (Inst.getOpcode()) {
1546     case ARM::LDRD:
1547     case ARM::LDRD_PRE:
1548     case ARM::LDRD_POST:
1549     case ARM::LDRH:
1550     case ARM::LDRH_PRE:
1551     case ARM::LDRH_POST:
1552     case ARM::LDRSH:
1553     case ARM::LDRSH_PRE:
1554     case ARM::LDRSH_POST:
1555     case ARM::LDRSB:
1556     case ARM::LDRSB_PRE:
1557     case ARM::LDRSB_POST:
1558     case ARM::LDRHTr:
1559     case ARM::LDRSBTr:
1560       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1561         return MCDisassembler::Fail;
1562       break;
1563     default:
1564       break;
1565     }
1566   }
1567 
1568   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1569     return MCDisassembler::Fail;
1570 
1571   if (type) {
1572     Inst.addOperand(MCOperand::CreateReg(0));
1573     Inst.addOperand(MCOperand::CreateImm(U | (imm << 4) | Rm));
1574   } else {
1575     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1576     return MCDisassembler::Fail;
1577     Inst.addOperand(MCOperand::CreateImm(U));
1578   }
1579 
1580   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1581     return MCDisassembler::Fail;
1582 
1583   return S;
1584 }
1585 
1586 static DecodeStatus DecodeRFEInstruction(llvm::MCInst &Inst, unsigned Insn,
1587                                  uint64_t Address, const void *Decoder) {
1588   DecodeStatus S = MCDisassembler::Success;
1589 
1590   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1591   unsigned mode = fieldFromInstruction32(Insn, 23, 2);
1592 
1593   switch (mode) {
1594     case 0:
1595       mode = ARM_AM::da;
1596       break;
1597     case 1:
1598       mode = ARM_AM::ia;
1599       break;
1600     case 2:
1601       mode = ARM_AM::db;
1602       break;
1603     case 3:
1604       mode = ARM_AM::ib;
1605       break;
1606   }
1607 
1608   Inst.addOperand(MCOperand::CreateImm(mode));
1609   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1610     return MCDisassembler::Fail;
1611 
1612   return S;
1613 }
1614 
1615 static DecodeStatus DecodeMemMultipleWritebackInstruction(llvm::MCInst &Inst,
1616                                   unsigned Insn,
1617                                   uint64_t Address, const void *Decoder) {
1618   DecodeStatus S = MCDisassembler::Success;
1619 
1620   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1621   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1622   unsigned reglist = fieldFromInstruction32(Insn, 0, 16);
1623 
1624   if (pred == 0xF) {
1625     switch (Inst.getOpcode()) {
1626       case ARM::LDMDA:
1627         Inst.setOpcode(ARM::RFEDA);
1628         break;
1629       case ARM::LDMDA_UPD:
1630         Inst.setOpcode(ARM::RFEDA_UPD);
1631         break;
1632       case ARM::LDMDB:
1633         Inst.setOpcode(ARM::RFEDB);
1634         break;
1635       case ARM::LDMDB_UPD:
1636         Inst.setOpcode(ARM::RFEDB_UPD);
1637         break;
1638       case ARM::LDMIA:
1639         Inst.setOpcode(ARM::RFEIA);
1640         break;
1641       case ARM::LDMIA_UPD:
1642         Inst.setOpcode(ARM::RFEIA_UPD);
1643         break;
1644       case ARM::LDMIB:
1645         Inst.setOpcode(ARM::RFEIB);
1646         break;
1647       case ARM::LDMIB_UPD:
1648         Inst.setOpcode(ARM::RFEIB_UPD);
1649         break;
1650       case ARM::STMDA:
1651         Inst.setOpcode(ARM::SRSDA);
1652         break;
1653       case ARM::STMDA_UPD:
1654         Inst.setOpcode(ARM::SRSDA_UPD);
1655         break;
1656       case ARM::STMDB:
1657         Inst.setOpcode(ARM::SRSDB);
1658         break;
1659       case ARM::STMDB_UPD:
1660         Inst.setOpcode(ARM::SRSDB_UPD);
1661         break;
1662       case ARM::STMIA:
1663         Inst.setOpcode(ARM::SRSIA);
1664         break;
1665       case ARM::STMIA_UPD:
1666         Inst.setOpcode(ARM::SRSIA_UPD);
1667         break;
1668       case ARM::STMIB:
1669         Inst.setOpcode(ARM::SRSIB);
1670         break;
1671       case ARM::STMIB_UPD:
1672         Inst.setOpcode(ARM::SRSIB_UPD);
1673         break;
1674       default:
1675         if (!Check(S, MCDisassembler::Fail)) return MCDisassembler::Fail;
1676     }
1677 
1678     // For stores (which become SRS's, the only operand is the mode.
1679     if (fieldFromInstruction32(Insn, 20, 1) == 0) {
1680       Inst.addOperand(
1681           MCOperand::CreateImm(fieldFromInstruction32(Insn, 0, 4)));
1682       return S;
1683     }
1684 
1685     return DecodeRFEInstruction(Inst, Insn, Address, Decoder);
1686   }
1687 
1688   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1689     return MCDisassembler::Fail;
1690   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1691     return MCDisassembler::Fail; // Tied
1692   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1693     return MCDisassembler::Fail;
1694   if (!Check(S, DecodeRegListOperand(Inst, reglist, Address, Decoder)))
1695     return MCDisassembler::Fail;
1696 
1697   return S;
1698 }
1699 
1700 static DecodeStatus DecodeCPSInstruction(llvm::MCInst &Inst, unsigned Insn,
1701                                  uint64_t Address, const void *Decoder) {
1702   unsigned imod = fieldFromInstruction32(Insn, 18, 2);
1703   unsigned M = fieldFromInstruction32(Insn, 17, 1);
1704   unsigned iflags = fieldFromInstruction32(Insn, 6, 3);
1705   unsigned mode = fieldFromInstruction32(Insn, 0, 5);
1706 
1707   DecodeStatus S = MCDisassembler::Success;
1708 
1709   // imod == '01' --> UNPREDICTABLE
1710   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
1711   // return failure here.  The '01' imod value is unprintable, so there's
1712   // nothing useful we could do even if we returned UNPREDICTABLE.
1713 
1714   if (imod == 1) return MCDisassembler::Fail;
1715 
1716   if (imod && M) {
1717     Inst.setOpcode(ARM::CPS3p);
1718     Inst.addOperand(MCOperand::CreateImm(imod));
1719     Inst.addOperand(MCOperand::CreateImm(iflags));
1720     Inst.addOperand(MCOperand::CreateImm(mode));
1721   } else if (imod && !M) {
1722     Inst.setOpcode(ARM::CPS2p);
1723     Inst.addOperand(MCOperand::CreateImm(imod));
1724     Inst.addOperand(MCOperand::CreateImm(iflags));
1725     if (mode) S = MCDisassembler::SoftFail;
1726   } else if (!imod && M) {
1727     Inst.setOpcode(ARM::CPS1p);
1728     Inst.addOperand(MCOperand::CreateImm(mode));
1729     if (iflags) S = MCDisassembler::SoftFail;
1730   } else {
1731     // imod == '00' && M == '0' --> UNPREDICTABLE
1732     Inst.setOpcode(ARM::CPS1p);
1733     Inst.addOperand(MCOperand::CreateImm(mode));
1734     S = MCDisassembler::SoftFail;
1735   }
1736 
1737   return S;
1738 }
1739 
1740 static DecodeStatus DecodeT2CPSInstruction(llvm::MCInst &Inst, unsigned Insn,
1741                                  uint64_t Address, const void *Decoder) {
1742   unsigned imod = fieldFromInstruction32(Insn, 9, 2);
1743   unsigned M = fieldFromInstruction32(Insn, 8, 1);
1744   unsigned iflags = fieldFromInstruction32(Insn, 5, 3);
1745   unsigned mode = fieldFromInstruction32(Insn, 0, 5);
1746 
1747   DecodeStatus S = MCDisassembler::Success;
1748 
1749   // imod == '01' --> UNPREDICTABLE
1750   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
1751   // return failure here.  The '01' imod value is unprintable, so there's
1752   // nothing useful we could do even if we returned UNPREDICTABLE.
1753 
1754   if (imod == 1) return MCDisassembler::Fail;
1755 
1756   if (imod && M) {
1757     Inst.setOpcode(ARM::t2CPS3p);
1758     Inst.addOperand(MCOperand::CreateImm(imod));
1759     Inst.addOperand(MCOperand::CreateImm(iflags));
1760     Inst.addOperand(MCOperand::CreateImm(mode));
1761   } else if (imod && !M) {
1762     Inst.setOpcode(ARM::t2CPS2p);
1763     Inst.addOperand(MCOperand::CreateImm(imod));
1764     Inst.addOperand(MCOperand::CreateImm(iflags));
1765     if (mode) S = MCDisassembler::SoftFail;
1766   } else if (!imod && M) {
1767     Inst.setOpcode(ARM::t2CPS1p);
1768     Inst.addOperand(MCOperand::CreateImm(mode));
1769     if (iflags) S = MCDisassembler::SoftFail;
1770   } else {
1771     // imod == '00' && M == '0' --> UNPREDICTABLE
1772     Inst.setOpcode(ARM::t2CPS1p);
1773     Inst.addOperand(MCOperand::CreateImm(mode));
1774     S = MCDisassembler::SoftFail;
1775   }
1776 
1777   return S;
1778 }
1779 
1780 static DecodeStatus DecodeT2MOVTWInstruction(llvm::MCInst &Inst, unsigned Insn,
1781                                  uint64_t Address, const void *Decoder) {
1782   DecodeStatus S = MCDisassembler::Success;
1783 
1784   unsigned Rd = fieldFromInstruction32(Insn, 8, 4);
1785   unsigned imm = 0;
1786 
1787   imm |= (fieldFromInstruction32(Insn, 0, 8) << 0);
1788   imm |= (fieldFromInstruction32(Insn, 12, 3) << 8);
1789   imm |= (fieldFromInstruction32(Insn, 16, 4) << 12);
1790   imm |= (fieldFromInstruction32(Insn, 26, 1) << 11);
1791 
1792   if (Inst.getOpcode() == ARM::t2MOVTi16)
1793     if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
1794       return MCDisassembler::Fail;
1795   if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
1796     return MCDisassembler::Fail;
1797 
1798   if (!tryAddingSymbolicOperand(Address, imm, false, 4, Inst, Decoder))
1799     Inst.addOperand(MCOperand::CreateImm(imm));
1800 
1801   return S;
1802 }
1803 
1804 static DecodeStatus DecodeArmMOVTWInstruction(llvm::MCInst &Inst, unsigned Insn,
1805                                  uint64_t Address, const void *Decoder) {
1806   DecodeStatus S = MCDisassembler::Success;
1807 
1808   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
1809   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1810   unsigned imm = 0;
1811 
1812   imm |= (fieldFromInstruction32(Insn, 0, 12) << 0);
1813   imm |= (fieldFromInstruction32(Insn, 16, 4) << 12);
1814 
1815   if (Inst.getOpcode() == ARM::MOVTi16)
1816     if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
1817       return MCDisassembler::Fail;
1818   if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
1819     return MCDisassembler::Fail;
1820 
1821   if (!tryAddingSymbolicOperand(Address, imm, false, 4, Inst, Decoder))
1822     Inst.addOperand(MCOperand::CreateImm(imm));
1823 
1824   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1825     return MCDisassembler::Fail;
1826 
1827   return S;
1828 }
1829 
1830 static DecodeStatus DecodeSMLAInstruction(llvm::MCInst &Inst, unsigned Insn,
1831                                  uint64_t Address, const void *Decoder) {
1832   DecodeStatus S = MCDisassembler::Success;
1833 
1834   unsigned Rd = fieldFromInstruction32(Insn, 16, 4);
1835   unsigned Rn = fieldFromInstruction32(Insn, 0, 4);
1836   unsigned Rm = fieldFromInstruction32(Insn, 8, 4);
1837   unsigned Ra = fieldFromInstruction32(Insn, 12, 4);
1838   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1839 
1840   if (pred == 0xF)
1841     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
1842 
1843   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
1844     return MCDisassembler::Fail;
1845   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
1846     return MCDisassembler::Fail;
1847   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1848     return MCDisassembler::Fail;
1849   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Ra, Address, Decoder)))
1850     return MCDisassembler::Fail;
1851 
1852   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1853     return MCDisassembler::Fail;
1854 
1855   return S;
1856 }
1857 
1858 static DecodeStatus DecodeAddrModeImm12Operand(llvm::MCInst &Inst, unsigned Val,
1859                            uint64_t Address, const void *Decoder) {
1860   DecodeStatus S = MCDisassembler::Success;
1861 
1862   unsigned add = fieldFromInstruction32(Val, 12, 1);
1863   unsigned imm = fieldFromInstruction32(Val, 0, 12);
1864   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
1865 
1866   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1867     return MCDisassembler::Fail;
1868 
1869   if (!add) imm *= -1;
1870   if (imm == 0 && !add) imm = INT32_MIN;
1871   Inst.addOperand(MCOperand::CreateImm(imm));
1872   if (Rn == 15)
1873     tryAddingPcLoadReferenceComment(Address, Address + imm + 8, Decoder);
1874 
1875   return S;
1876 }
1877 
1878 static DecodeStatus DecodeAddrMode5Operand(llvm::MCInst &Inst, unsigned Val,
1879                                    uint64_t Address, const void *Decoder) {
1880   DecodeStatus S = MCDisassembler::Success;
1881 
1882   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
1883   unsigned U = fieldFromInstruction32(Val, 8, 1);
1884   unsigned imm = fieldFromInstruction32(Val, 0, 8);
1885 
1886   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1887     return MCDisassembler::Fail;
1888 
1889   if (U)
1890     Inst.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(ARM_AM::add, imm)));
1891   else
1892     Inst.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(ARM_AM::sub, imm)));
1893 
1894   return S;
1895 }
1896 
1897 static DecodeStatus DecodeAddrMode7Operand(llvm::MCInst &Inst, unsigned Val,
1898                                    uint64_t Address, const void *Decoder) {
1899   return DecodeGPRRegisterClass(Inst, Val, Address, Decoder);
1900 }
1901 
1902 static DecodeStatus
1903 DecodeBranchImmInstruction(llvm::MCInst &Inst, unsigned Insn,
1904                            uint64_t Address, const void *Decoder) {
1905   DecodeStatus S = MCDisassembler::Success;
1906 
1907   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1908   unsigned imm = fieldFromInstruction32(Insn, 0, 24) << 2;
1909 
1910   if (pred == 0xF) {
1911     Inst.setOpcode(ARM::BLXi);
1912     imm |= fieldFromInstruction32(Insn, 24, 1) << 1;
1913     Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(imm)));
1914     return S;
1915   }
1916 
1917   if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<26>(imm) + 8, true,
1918                                 4, Inst, Decoder))
1919     Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(imm)));
1920   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1921     return MCDisassembler::Fail;
1922 
1923   return S;
1924 }
1925 
1926 
1927 static DecodeStatus DecodeAddrMode6Operand(llvm::MCInst &Inst, unsigned Val,
1928                                    uint64_t Address, const void *Decoder) {
1929   DecodeStatus S = MCDisassembler::Success;
1930 
1931   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
1932   unsigned align = fieldFromInstruction32(Val, 4, 2);
1933 
1934   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1935     return MCDisassembler::Fail;
1936   if (!align)
1937     Inst.addOperand(MCOperand::CreateImm(0));
1938   else
1939     Inst.addOperand(MCOperand::CreateImm(4 << align));
1940 
1941   return S;
1942 }
1943 
1944 static DecodeStatus DecodeVLDInstruction(llvm::MCInst &Inst, unsigned Insn,
1945                                    uint64_t Address, const void *Decoder) {
1946   DecodeStatus S = MCDisassembler::Success;
1947 
1948   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
1949   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
1950   unsigned wb = fieldFromInstruction32(Insn, 16, 4);
1951   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1952   Rn |= fieldFromInstruction32(Insn, 4, 2) << 4;
1953   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1954 
1955   // First output register
1956   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
1957     return MCDisassembler::Fail;
1958 
1959   // Second output register
1960   switch (Inst.getOpcode()) {
1961     case ARM::VLD3d8:
1962     case ARM::VLD3d16:
1963     case ARM::VLD3d32:
1964     case ARM::VLD3d8_UPD:
1965     case ARM::VLD3d16_UPD:
1966     case ARM::VLD3d32_UPD:
1967     case ARM::VLD4d8:
1968     case ARM::VLD4d16:
1969     case ARM::VLD4d32:
1970     case ARM::VLD4d8_UPD:
1971     case ARM::VLD4d16_UPD:
1972     case ARM::VLD4d32_UPD:
1973       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
1974         return MCDisassembler::Fail;
1975       break;
1976     case ARM::VLD3q8:
1977     case ARM::VLD3q16:
1978     case ARM::VLD3q32:
1979     case ARM::VLD3q8_UPD:
1980     case ARM::VLD3q16_UPD:
1981     case ARM::VLD3q32_UPD:
1982     case ARM::VLD4q8:
1983     case ARM::VLD4q16:
1984     case ARM::VLD4q32:
1985     case ARM::VLD4q8_UPD:
1986     case ARM::VLD4q16_UPD:
1987     case ARM::VLD4q32_UPD:
1988       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
1989         return MCDisassembler::Fail;
1990     default:
1991       break;
1992   }
1993 
1994   // Third output register
1995   switch(Inst.getOpcode()) {
1996     case ARM::VLD3d8:
1997     case ARM::VLD3d16:
1998     case ARM::VLD3d32:
1999     case ARM::VLD3d8_UPD:
2000     case ARM::VLD3d16_UPD:
2001     case ARM::VLD3d32_UPD:
2002     case ARM::VLD4d8:
2003     case ARM::VLD4d16:
2004     case ARM::VLD4d32:
2005     case ARM::VLD4d8_UPD:
2006     case ARM::VLD4d16_UPD:
2007     case ARM::VLD4d32_UPD:
2008       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2009         return MCDisassembler::Fail;
2010       break;
2011     case ARM::VLD3q8:
2012     case ARM::VLD3q16:
2013     case ARM::VLD3q32:
2014     case ARM::VLD3q8_UPD:
2015     case ARM::VLD3q16_UPD:
2016     case ARM::VLD3q32_UPD:
2017     case ARM::VLD4q8:
2018     case ARM::VLD4q16:
2019     case ARM::VLD4q32:
2020     case ARM::VLD4q8_UPD:
2021     case ARM::VLD4q16_UPD:
2022     case ARM::VLD4q32_UPD:
2023       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
2024         return MCDisassembler::Fail;
2025       break;
2026     default:
2027       break;
2028   }
2029 
2030   // Fourth output register
2031   switch (Inst.getOpcode()) {
2032     case ARM::VLD4d8:
2033     case ARM::VLD4d16:
2034     case ARM::VLD4d32:
2035     case ARM::VLD4d8_UPD:
2036     case ARM::VLD4d16_UPD:
2037     case ARM::VLD4d32_UPD:
2038       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
2039         return MCDisassembler::Fail;
2040       break;
2041     case ARM::VLD4q8:
2042     case ARM::VLD4q16:
2043     case ARM::VLD4q32:
2044     case ARM::VLD4q8_UPD:
2045     case ARM::VLD4q16_UPD:
2046     case ARM::VLD4q32_UPD:
2047       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
2048         return MCDisassembler::Fail;
2049       break;
2050     default:
2051       break;
2052   }
2053 
2054   // Writeback operand
2055   switch (Inst.getOpcode()) {
2056     case ARM::VLD1d8wb_fixed:
2057     case ARM::VLD1d16wb_fixed:
2058     case ARM::VLD1d32wb_fixed:
2059     case ARM::VLD1d64wb_fixed:
2060     case ARM::VLD1d8wb_register:
2061     case ARM::VLD1d16wb_register:
2062     case ARM::VLD1d32wb_register:
2063     case ARM::VLD1d64wb_register:
2064     case ARM::VLD1q8wb_fixed:
2065     case ARM::VLD1q16wb_fixed:
2066     case ARM::VLD1q32wb_fixed:
2067     case ARM::VLD1q64wb_fixed:
2068     case ARM::VLD1q8wb_register:
2069     case ARM::VLD1q16wb_register:
2070     case ARM::VLD1q32wb_register:
2071     case ARM::VLD1q64wb_register:
2072     case ARM::VLD1d8Twb_fixed:
2073     case ARM::VLD1d8Twb_register:
2074     case ARM::VLD1d16Twb_fixed:
2075     case ARM::VLD1d16Twb_register:
2076     case ARM::VLD1d32Twb_fixed:
2077     case ARM::VLD1d32Twb_register:
2078     case ARM::VLD1d64Twb_fixed:
2079     case ARM::VLD1d64Twb_register:
2080     case ARM::VLD1d8Qwb_fixed:
2081     case ARM::VLD1d8Qwb_register:
2082     case ARM::VLD1d16Qwb_fixed:
2083     case ARM::VLD1d16Qwb_register:
2084     case ARM::VLD1d32Qwb_fixed:
2085     case ARM::VLD1d32Qwb_register:
2086     case ARM::VLD1d64Qwb_fixed:
2087     case ARM::VLD1d64Qwb_register:
2088     case ARM::VLD2d8wb_fixed:
2089     case ARM::VLD2d16wb_fixed:
2090     case ARM::VLD2d32wb_fixed:
2091     case ARM::VLD2q8wb_fixed:
2092     case ARM::VLD2q16wb_fixed:
2093     case ARM::VLD2q32wb_fixed:
2094     case ARM::VLD2d8wb_register:
2095     case ARM::VLD2d16wb_register:
2096     case ARM::VLD2d32wb_register:
2097     case ARM::VLD2q8wb_register:
2098     case ARM::VLD2q16wb_register:
2099     case ARM::VLD2q32wb_register:
2100     case ARM::VLD2b8wb_fixed:
2101     case ARM::VLD2b16wb_fixed:
2102     case ARM::VLD2b32wb_fixed:
2103     case ARM::VLD2b8wb_register:
2104     case ARM::VLD2b16wb_register:
2105     case ARM::VLD2b32wb_register:
2106     case ARM::VLD3d8_UPD:
2107     case ARM::VLD3d16_UPD:
2108     case ARM::VLD3d32_UPD:
2109     case ARM::VLD3q8_UPD:
2110     case ARM::VLD3q16_UPD:
2111     case ARM::VLD3q32_UPD:
2112     case ARM::VLD4d8_UPD:
2113     case ARM::VLD4d16_UPD:
2114     case ARM::VLD4d32_UPD:
2115     case ARM::VLD4q8_UPD:
2116     case ARM::VLD4q16_UPD:
2117     case ARM::VLD4q32_UPD:
2118       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
2119         return MCDisassembler::Fail;
2120       break;
2121     default:
2122       break;
2123   }
2124 
2125   // AddrMode6 Base (register+alignment)
2126   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
2127     return MCDisassembler::Fail;
2128 
2129   // AddrMode6 Offset (register)
2130   switch (Inst.getOpcode()) {
2131   default:
2132     // The below have been updated to have explicit am6offset split
2133     // between fixed and register offset. For those instructions not
2134     // yet updated, we need to add an additional reg0 operand for the
2135     // fixed variant.
2136     //
2137     // The fixed offset encodes as Rm == 0xd, so we check for that.
2138     if (Rm == 0xd) {
2139       Inst.addOperand(MCOperand::CreateReg(0));
2140       break;
2141     }
2142     // Fall through to handle the register offset variant.
2143   case ARM::VLD1d8wb_fixed:
2144   case ARM::VLD1d16wb_fixed:
2145   case ARM::VLD1d32wb_fixed:
2146   case ARM::VLD1d64wb_fixed:
2147   case ARM::VLD1d8Twb_fixed:
2148   case ARM::VLD1d16Twb_fixed:
2149   case ARM::VLD1d32Twb_fixed:
2150   case ARM::VLD1d64Twb_fixed:
2151   case ARM::VLD1d8Qwb_fixed:
2152   case ARM::VLD1d16Qwb_fixed:
2153   case ARM::VLD1d32Qwb_fixed:
2154   case ARM::VLD1d64Qwb_fixed:
2155   case ARM::VLD1d8wb_register:
2156   case ARM::VLD1d16wb_register:
2157   case ARM::VLD1d32wb_register:
2158   case ARM::VLD1d64wb_register:
2159   case ARM::VLD1q8wb_fixed:
2160   case ARM::VLD1q16wb_fixed:
2161   case ARM::VLD1q32wb_fixed:
2162   case ARM::VLD1q64wb_fixed:
2163   case ARM::VLD1q8wb_register:
2164   case ARM::VLD1q16wb_register:
2165   case ARM::VLD1q32wb_register:
2166   case ARM::VLD1q64wb_register:
2167     // The fixed offset post-increment encodes Rm == 0xd. The no-writeback
2168     // variant encodes Rm == 0xf. Anything else is a register offset post-
2169     // increment and we need to add the register operand to the instruction.
2170     if (Rm != 0xD && Rm != 0xF &&
2171         !Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2172       return MCDisassembler::Fail;
2173     break;
2174   }
2175 
2176   return S;
2177 }
2178 
2179 static DecodeStatus DecodeVSTInstruction(llvm::MCInst &Inst, unsigned Insn,
2180                                  uint64_t Address, const void *Decoder) {
2181   DecodeStatus S = MCDisassembler::Success;
2182 
2183   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2184   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2185   unsigned wb = fieldFromInstruction32(Insn, 16, 4);
2186   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2187   Rn |= fieldFromInstruction32(Insn, 4, 2) << 4;
2188   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2189 
2190   // Writeback Operand
2191   switch (Inst.getOpcode()) {
2192     case ARM::VST1d8wb_fixed:
2193     case ARM::VST1d16wb_fixed:
2194     case ARM::VST1d32wb_fixed:
2195     case ARM::VST1d64wb_fixed:
2196     case ARM::VST1d8wb_register:
2197     case ARM::VST1d16wb_register:
2198     case ARM::VST1d32wb_register:
2199     case ARM::VST1d64wb_register:
2200     case ARM::VST1q8wb_fixed:
2201     case ARM::VST1q16wb_fixed:
2202     case ARM::VST1q32wb_fixed:
2203     case ARM::VST1q64wb_fixed:
2204     case ARM::VST1q8wb_register:
2205     case ARM::VST1q16wb_register:
2206     case ARM::VST1q32wb_register:
2207     case ARM::VST1q64wb_register:
2208     case ARM::VST1d8Twb_fixed:
2209     case ARM::VST1d16Twb_fixed:
2210     case ARM::VST1d32Twb_fixed:
2211     case ARM::VST1d64Twb_fixed:
2212     case ARM::VST1d8Twb_register:
2213     case ARM::VST1d16Twb_register:
2214     case ARM::VST1d32Twb_register:
2215     case ARM::VST1d64Twb_register:
2216     case ARM::VST1d8Qwb_fixed:
2217     case ARM::VST1d16Qwb_fixed:
2218     case ARM::VST1d32Qwb_fixed:
2219     case ARM::VST1d64Qwb_fixed:
2220     case ARM::VST1d8Qwb_register:
2221     case ARM::VST1d16Qwb_register:
2222     case ARM::VST1d32Qwb_register:
2223     case ARM::VST1d64Qwb_register:
2224     case ARM::VST2d8_UPD:
2225     case ARM::VST2d16_UPD:
2226     case ARM::VST2d32_UPD:
2227     case ARM::VST2q8_UPD:
2228     case ARM::VST2q16_UPD:
2229     case ARM::VST2q32_UPD:
2230     case ARM::VST2b8_UPD:
2231     case ARM::VST2b16_UPD:
2232     case ARM::VST2b32_UPD:
2233     case ARM::VST3d8_UPD:
2234     case ARM::VST3d16_UPD:
2235     case ARM::VST3d32_UPD:
2236     case ARM::VST3q8_UPD:
2237     case ARM::VST3q16_UPD:
2238     case ARM::VST3q32_UPD:
2239     case ARM::VST4d8_UPD:
2240     case ARM::VST4d16_UPD:
2241     case ARM::VST4d32_UPD:
2242     case ARM::VST4q8_UPD:
2243     case ARM::VST4q16_UPD:
2244     case ARM::VST4q32_UPD:
2245       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
2246         return MCDisassembler::Fail;
2247       break;
2248     default:
2249       break;
2250   }
2251 
2252   // AddrMode6 Base (register+alignment)
2253   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
2254     return MCDisassembler::Fail;
2255 
2256   // AddrMode6 Offset (register)
2257   switch (Inst.getOpcode()) {
2258     default:
2259       if (Rm == 0xD)
2260         Inst.addOperand(MCOperand::CreateReg(0));
2261       else if (Rm != 0xF) {
2262         if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2263           return MCDisassembler::Fail;
2264       }
2265       break;
2266     case ARM::VST1d8wb_fixed:
2267     case ARM::VST1d16wb_fixed:
2268     case ARM::VST1d32wb_fixed:
2269     case ARM::VST1d64wb_fixed:
2270     case ARM::VST1q8wb_fixed:
2271     case ARM::VST1q16wb_fixed:
2272     case ARM::VST1q32wb_fixed:
2273     case ARM::VST1q64wb_fixed:
2274       break;
2275   }
2276 
2277 
2278   // First input register
2279   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2280     return MCDisassembler::Fail;
2281 
2282   // Second input register
2283   switch (Inst.getOpcode()) {
2284     case ARM::VST3d8:
2285     case ARM::VST3d16:
2286     case ARM::VST3d32:
2287     case ARM::VST3d8_UPD:
2288     case ARM::VST3d16_UPD:
2289     case ARM::VST3d32_UPD:
2290     case ARM::VST4d8:
2291     case ARM::VST4d16:
2292     case ARM::VST4d32:
2293     case ARM::VST4d8_UPD:
2294     case ARM::VST4d16_UPD:
2295     case ARM::VST4d32_UPD:
2296       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
2297         return MCDisassembler::Fail;
2298       break;
2299     case ARM::VST3q8:
2300     case ARM::VST3q16:
2301     case ARM::VST3q32:
2302     case ARM::VST3q8_UPD:
2303     case ARM::VST3q16_UPD:
2304     case ARM::VST3q32_UPD:
2305     case ARM::VST4q8:
2306     case ARM::VST4q16:
2307     case ARM::VST4q32:
2308     case ARM::VST4q8_UPD:
2309     case ARM::VST4q16_UPD:
2310     case ARM::VST4q32_UPD:
2311       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2312         return MCDisassembler::Fail;
2313       break;
2314     default:
2315       break;
2316   }
2317 
2318   // Third input register
2319   switch (Inst.getOpcode()) {
2320     case ARM::VST3d8:
2321     case ARM::VST3d16:
2322     case ARM::VST3d32:
2323     case ARM::VST3d8_UPD:
2324     case ARM::VST3d16_UPD:
2325     case ARM::VST3d32_UPD:
2326     case ARM::VST4d8:
2327     case ARM::VST4d16:
2328     case ARM::VST4d32:
2329     case ARM::VST4d8_UPD:
2330     case ARM::VST4d16_UPD:
2331     case ARM::VST4d32_UPD:
2332       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2333         return MCDisassembler::Fail;
2334       break;
2335     case ARM::VST3q8:
2336     case ARM::VST3q16:
2337     case ARM::VST3q32:
2338     case ARM::VST3q8_UPD:
2339     case ARM::VST3q16_UPD:
2340     case ARM::VST3q32_UPD:
2341     case ARM::VST4q8:
2342     case ARM::VST4q16:
2343     case ARM::VST4q32:
2344     case ARM::VST4q8_UPD:
2345     case ARM::VST4q16_UPD:
2346     case ARM::VST4q32_UPD:
2347       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
2348         return MCDisassembler::Fail;
2349       break;
2350     default:
2351       break;
2352   }
2353 
2354   // Fourth input register
2355   switch (Inst.getOpcode()) {
2356     case ARM::VST4d8:
2357     case ARM::VST4d16:
2358     case ARM::VST4d32:
2359     case ARM::VST4d8_UPD:
2360     case ARM::VST4d16_UPD:
2361     case ARM::VST4d32_UPD:
2362       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
2363         return MCDisassembler::Fail;
2364       break;
2365     case ARM::VST4q8:
2366     case ARM::VST4q16:
2367     case ARM::VST4q32:
2368     case ARM::VST4q8_UPD:
2369     case ARM::VST4q16_UPD:
2370     case ARM::VST4q32_UPD:
2371       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
2372         return MCDisassembler::Fail;
2373       break;
2374     default:
2375       break;
2376   }
2377 
2378   return S;
2379 }
2380 
2381 static DecodeStatus DecodeVLD1DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2382                                     uint64_t Address, const void *Decoder) {
2383   DecodeStatus S = MCDisassembler::Success;
2384 
2385   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2386   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2387   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2388   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2389   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2390   unsigned size = fieldFromInstruction32(Insn, 6, 2);
2391 
2392   align *= (1 << size);
2393 
2394   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2395     return MCDisassembler::Fail;
2396   if (Rm != 0xF) {
2397     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2398       return MCDisassembler::Fail;
2399   }
2400 
2401   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2402     return MCDisassembler::Fail;
2403   Inst.addOperand(MCOperand::CreateImm(align));
2404 
2405   // The fixed offset post-increment encodes Rm == 0xd. The no-writeback
2406   // variant encodes Rm == 0xf. Anything else is a register offset post-
2407   // increment and we need to add the register operand to the instruction.
2408   if (Rm != 0xD && Rm != 0xF &&
2409       !Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2410     return MCDisassembler::Fail;
2411 
2412   return S;
2413 }
2414 
2415 static DecodeStatus DecodeVLD2DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2416                                     uint64_t Address, const void *Decoder) {
2417   DecodeStatus S = MCDisassembler::Success;
2418 
2419   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2420   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2421   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2422   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2423   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2424   unsigned size = 1 << fieldFromInstruction32(Insn, 6, 2);
2425   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2426   align *= 2*size;
2427 
2428   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2429     return MCDisassembler::Fail;
2430   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
2431     return MCDisassembler::Fail;
2432   if (Rm != 0xF) {
2433     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2434       return MCDisassembler::Fail;
2435   }
2436 
2437   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2438     return MCDisassembler::Fail;
2439   Inst.addOperand(MCOperand::CreateImm(align));
2440 
2441   if (Rm == 0xD)
2442     Inst.addOperand(MCOperand::CreateReg(0));
2443   else if (Rm != 0xF) {
2444     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2445       return MCDisassembler::Fail;
2446   }
2447 
2448   return S;
2449 }
2450 
2451 static DecodeStatus DecodeVLD3DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2452                                     uint64_t Address, const void *Decoder) {
2453   DecodeStatus S = MCDisassembler::Success;
2454 
2455   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2456   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2457   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2458   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2459   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2460 
2461   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2462     return MCDisassembler::Fail;
2463   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
2464     return MCDisassembler::Fail;
2465   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
2466     return MCDisassembler::Fail;
2467   if (Rm != 0xF) {
2468     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2469       return MCDisassembler::Fail;
2470   }
2471 
2472   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2473     return MCDisassembler::Fail;
2474   Inst.addOperand(MCOperand::CreateImm(0));
2475 
2476   if (Rm == 0xD)
2477     Inst.addOperand(MCOperand::CreateReg(0));
2478   else if (Rm != 0xF) {
2479     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2480       return MCDisassembler::Fail;
2481   }
2482 
2483   return S;
2484 }
2485 
2486 static DecodeStatus DecodeVLD4DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2487                                     uint64_t Address, const void *Decoder) {
2488   DecodeStatus S = MCDisassembler::Success;
2489 
2490   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2491   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2492   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2493   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2494   unsigned size = fieldFromInstruction32(Insn, 6, 2);
2495   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2496   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2497 
2498   if (size == 0x3) {
2499     size = 4;
2500     align = 16;
2501   } else {
2502     if (size == 2) {
2503       size = 1 << size;
2504       align *= 8;
2505     } else {
2506       size = 1 << size;
2507       align *= 4*size;
2508     }
2509   }
2510 
2511   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2512     return MCDisassembler::Fail;
2513   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
2514     return MCDisassembler::Fail;
2515   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
2516     return MCDisassembler::Fail;
2517   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3*inc)%32, Address, Decoder)))
2518     return MCDisassembler::Fail;
2519   if (Rm != 0xF) {
2520     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2521       return MCDisassembler::Fail;
2522   }
2523 
2524   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2525     return MCDisassembler::Fail;
2526   Inst.addOperand(MCOperand::CreateImm(align));
2527 
2528   if (Rm == 0xD)
2529     Inst.addOperand(MCOperand::CreateReg(0));
2530   else if (Rm != 0xF) {
2531     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2532       return MCDisassembler::Fail;
2533   }
2534 
2535   return S;
2536 }
2537 
2538 static DecodeStatus
2539 DecodeNEONModImmInstruction(llvm::MCInst &Inst, unsigned Insn,
2540                             uint64_t Address, const void *Decoder) {
2541   DecodeStatus S = MCDisassembler::Success;
2542 
2543   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2544   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2545   unsigned imm = fieldFromInstruction32(Insn, 0, 4);
2546   imm |= fieldFromInstruction32(Insn, 16, 3) << 4;
2547   imm |= fieldFromInstruction32(Insn, 24, 1) << 7;
2548   imm |= fieldFromInstruction32(Insn, 8, 4) << 8;
2549   imm |= fieldFromInstruction32(Insn, 5, 1) << 12;
2550   unsigned Q = fieldFromInstruction32(Insn, 6, 1);
2551 
2552   if (Q) {
2553     if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2554     return MCDisassembler::Fail;
2555   } else {
2556     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2557     return MCDisassembler::Fail;
2558   }
2559 
2560   Inst.addOperand(MCOperand::CreateImm(imm));
2561 
2562   switch (Inst.getOpcode()) {
2563     case ARM::VORRiv4i16:
2564     case ARM::VORRiv2i32:
2565     case ARM::VBICiv4i16:
2566     case ARM::VBICiv2i32:
2567       if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2568         return MCDisassembler::Fail;
2569       break;
2570     case ARM::VORRiv8i16:
2571     case ARM::VORRiv4i32:
2572     case ARM::VBICiv8i16:
2573     case ARM::VBICiv4i32:
2574       if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2575         return MCDisassembler::Fail;
2576       break;
2577     default:
2578       break;
2579   }
2580 
2581   return S;
2582 }
2583 
2584 static DecodeStatus DecodeVSHLMaxInstruction(llvm::MCInst &Inst, unsigned Insn,
2585                                         uint64_t Address, const void *Decoder) {
2586   DecodeStatus S = MCDisassembler::Success;
2587 
2588   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2589   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2590   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2591   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
2592   unsigned size = fieldFromInstruction32(Insn, 18, 2);
2593 
2594   if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2595     return MCDisassembler::Fail;
2596   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
2597     return MCDisassembler::Fail;
2598   Inst.addOperand(MCOperand::CreateImm(8 << size));
2599 
2600   return S;
2601 }
2602 
2603 static DecodeStatus DecodeShiftRight8Imm(llvm::MCInst &Inst, unsigned Val,
2604                                uint64_t Address, const void *Decoder) {
2605   Inst.addOperand(MCOperand::CreateImm(8 - Val));
2606   return MCDisassembler::Success;
2607 }
2608 
2609 static DecodeStatus DecodeShiftRight16Imm(llvm::MCInst &Inst, unsigned Val,
2610                                uint64_t Address, const void *Decoder) {
2611   Inst.addOperand(MCOperand::CreateImm(16 - Val));
2612   return MCDisassembler::Success;
2613 }
2614 
2615 static DecodeStatus DecodeShiftRight32Imm(llvm::MCInst &Inst, unsigned Val,
2616                                uint64_t Address, const void *Decoder) {
2617   Inst.addOperand(MCOperand::CreateImm(32 - Val));
2618   return MCDisassembler::Success;
2619 }
2620 
2621 static DecodeStatus DecodeShiftRight64Imm(llvm::MCInst &Inst, unsigned Val,
2622                                uint64_t Address, const void *Decoder) {
2623   Inst.addOperand(MCOperand::CreateImm(64 - Val));
2624   return MCDisassembler::Success;
2625 }
2626 
2627 static DecodeStatus DecodeTBLInstruction(llvm::MCInst &Inst, unsigned Insn,
2628                                uint64_t Address, const void *Decoder) {
2629   DecodeStatus S = MCDisassembler::Success;
2630 
2631   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2632   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2633   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2634   Rn |= fieldFromInstruction32(Insn, 7, 1) << 4;
2635   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2636   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
2637   unsigned op = fieldFromInstruction32(Insn, 6, 1);
2638   unsigned length = fieldFromInstruction32(Insn, 8, 2) + 1;
2639 
2640   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2641     return MCDisassembler::Fail;
2642   if (op) {
2643     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2644     return MCDisassembler::Fail; // Writeback
2645   }
2646 
2647   for (unsigned i = 0; i < length; ++i) {
2648     if (!Check(S, DecodeDPRRegisterClass(Inst, (Rn+i)%32, Address, Decoder)))
2649     return MCDisassembler::Fail;
2650   }
2651 
2652   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
2653     return MCDisassembler::Fail;
2654 
2655   return S;
2656 }
2657 
2658 static DecodeStatus DecodeThumbAddSpecialReg(llvm::MCInst &Inst, uint16_t Insn,
2659                                      uint64_t Address, const void *Decoder) {
2660   DecodeStatus S = MCDisassembler::Success;
2661 
2662   unsigned dst = fieldFromInstruction16(Insn, 8, 3);
2663   unsigned imm = fieldFromInstruction16(Insn, 0, 8);
2664 
2665   if (!Check(S, DecodetGPRRegisterClass(Inst, dst, Address, Decoder)))
2666     return MCDisassembler::Fail;
2667 
2668   switch(Inst.getOpcode()) {
2669     default:
2670       return MCDisassembler::Fail;
2671     case ARM::tADR:
2672       break; // tADR does not explicitly represent the PC as an operand.
2673     case ARM::tADDrSPi:
2674       Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2675       break;
2676   }
2677 
2678   Inst.addOperand(MCOperand::CreateImm(imm));
2679   return S;
2680 }
2681 
2682 static DecodeStatus DecodeThumbBROperand(llvm::MCInst &Inst, unsigned Val,
2683                                  uint64_t Address, const void *Decoder) {
2684   Inst.addOperand(MCOperand::CreateImm(SignExtend32<12>(Val << 1)));
2685   return MCDisassembler::Success;
2686 }
2687 
2688 static DecodeStatus DecodeT2BROperand(llvm::MCInst &Inst, unsigned Val,
2689                                  uint64_t Address, const void *Decoder) {
2690   Inst.addOperand(MCOperand::CreateImm(SignExtend32<21>(Val)));
2691   return MCDisassembler::Success;
2692 }
2693 
2694 static DecodeStatus DecodeThumbCmpBROperand(llvm::MCInst &Inst, unsigned Val,
2695                                  uint64_t Address, const void *Decoder) {
2696   Inst.addOperand(MCOperand::CreateImm(SignExtend32<7>(Val << 1)));
2697   return MCDisassembler::Success;
2698 }
2699 
2700 static DecodeStatus DecodeThumbAddrModeRR(llvm::MCInst &Inst, unsigned Val,
2701                                  uint64_t Address, const void *Decoder) {
2702   DecodeStatus S = MCDisassembler::Success;
2703 
2704   unsigned Rn = fieldFromInstruction32(Val, 0, 3);
2705   unsigned Rm = fieldFromInstruction32(Val, 3, 3);
2706 
2707   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
2708     return MCDisassembler::Fail;
2709   if (!Check(S, DecodetGPRRegisterClass(Inst, Rm, Address, Decoder)))
2710     return MCDisassembler::Fail;
2711 
2712   return S;
2713 }
2714 
2715 static DecodeStatus DecodeThumbAddrModeIS(llvm::MCInst &Inst, unsigned Val,
2716                                   uint64_t Address, const void *Decoder) {
2717   DecodeStatus S = MCDisassembler::Success;
2718 
2719   unsigned Rn = fieldFromInstruction32(Val, 0, 3);
2720   unsigned imm = fieldFromInstruction32(Val, 3, 5);
2721 
2722   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
2723     return MCDisassembler::Fail;
2724   Inst.addOperand(MCOperand::CreateImm(imm));
2725 
2726   return S;
2727 }
2728 
2729 static DecodeStatus DecodeThumbAddrModePC(llvm::MCInst &Inst, unsigned Val,
2730                                   uint64_t Address, const void *Decoder) {
2731   unsigned imm = Val << 2;
2732 
2733   Inst.addOperand(MCOperand::CreateImm(imm));
2734   tryAddingPcLoadReferenceComment(Address, (Address & ~2u) + imm + 4, Decoder);
2735 
2736   return MCDisassembler::Success;
2737 }
2738 
2739 static DecodeStatus DecodeThumbAddrModeSP(llvm::MCInst &Inst, unsigned Val,
2740                                   uint64_t Address, const void *Decoder) {
2741   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2742   Inst.addOperand(MCOperand::CreateImm(Val));
2743 
2744   return MCDisassembler::Success;
2745 }
2746 
2747 static DecodeStatus DecodeT2AddrModeSOReg(llvm::MCInst &Inst, unsigned Val,
2748                                   uint64_t Address, const void *Decoder) {
2749   DecodeStatus S = MCDisassembler::Success;
2750 
2751   unsigned Rn = fieldFromInstruction32(Val, 6, 4);
2752   unsigned Rm = fieldFromInstruction32(Val, 2, 4);
2753   unsigned imm = fieldFromInstruction32(Val, 0, 2);
2754 
2755   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2756     return MCDisassembler::Fail;
2757   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
2758     return MCDisassembler::Fail;
2759   Inst.addOperand(MCOperand::CreateImm(imm));
2760 
2761   return S;
2762 }
2763 
2764 static DecodeStatus DecodeT2LoadShift(llvm::MCInst &Inst, unsigned Insn,
2765                               uint64_t Address, const void *Decoder) {
2766   DecodeStatus S = MCDisassembler::Success;
2767 
2768   switch (Inst.getOpcode()) {
2769     case ARM::t2PLDs:
2770     case ARM::t2PLDWs:
2771     case ARM::t2PLIs:
2772       break;
2773     default: {
2774       unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2775       if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
2776     return MCDisassembler::Fail;
2777     }
2778   }
2779 
2780   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2781   if (Rn == 0xF) {
2782     switch (Inst.getOpcode()) {
2783       case ARM::t2LDRBs:
2784         Inst.setOpcode(ARM::t2LDRBpci);
2785         break;
2786       case ARM::t2LDRHs:
2787         Inst.setOpcode(ARM::t2LDRHpci);
2788         break;
2789       case ARM::t2LDRSHs:
2790         Inst.setOpcode(ARM::t2LDRSHpci);
2791         break;
2792       case ARM::t2LDRSBs:
2793         Inst.setOpcode(ARM::t2LDRSBpci);
2794         break;
2795       case ARM::t2PLDs:
2796         Inst.setOpcode(ARM::t2PLDi12);
2797         Inst.addOperand(MCOperand::CreateReg(ARM::PC));
2798         break;
2799       default:
2800         return MCDisassembler::Fail;
2801     }
2802 
2803     int imm = fieldFromInstruction32(Insn, 0, 12);
2804     if (!fieldFromInstruction32(Insn, 23, 1)) imm *= -1;
2805     Inst.addOperand(MCOperand::CreateImm(imm));
2806 
2807     return S;
2808   }
2809 
2810   unsigned addrmode = fieldFromInstruction32(Insn, 4, 2);
2811   addrmode |= fieldFromInstruction32(Insn, 0, 4) << 2;
2812   addrmode |= fieldFromInstruction32(Insn, 16, 4) << 6;
2813   if (!Check(S, DecodeT2AddrModeSOReg(Inst, addrmode, Address, Decoder)))
2814     return MCDisassembler::Fail;
2815 
2816   return S;
2817 }
2818 
2819 static DecodeStatus DecodeT2Imm8S4(llvm::MCInst &Inst, unsigned Val,
2820                            uint64_t Address, const void *Decoder) {
2821   int imm = Val & 0xFF;
2822   if (!(Val & 0x100)) imm *= -1;
2823   Inst.addOperand(MCOperand::CreateImm(imm << 2));
2824 
2825   return MCDisassembler::Success;
2826 }
2827 
2828 static DecodeStatus DecodeT2AddrModeImm8s4(llvm::MCInst &Inst, unsigned Val,
2829                                    uint64_t Address, const void *Decoder) {
2830   DecodeStatus S = MCDisassembler::Success;
2831 
2832   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
2833   unsigned imm = fieldFromInstruction32(Val, 0, 9);
2834 
2835   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2836     return MCDisassembler::Fail;
2837   if (!Check(S, DecodeT2Imm8S4(Inst, imm, Address, Decoder)))
2838     return MCDisassembler::Fail;
2839 
2840   return S;
2841 }
2842 
2843 static DecodeStatus DecodeT2AddrModeImm0_1020s4(llvm::MCInst &Inst,unsigned Val,
2844                                    uint64_t Address, const void *Decoder) {
2845   DecodeStatus S = MCDisassembler::Success;
2846 
2847   unsigned Rn = fieldFromInstruction32(Val, 8, 4);
2848   unsigned imm = fieldFromInstruction32(Val, 0, 8);
2849 
2850   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
2851     return MCDisassembler::Fail;
2852 
2853   Inst.addOperand(MCOperand::CreateImm(imm));
2854 
2855   return S;
2856 }
2857 
2858 static DecodeStatus DecodeT2Imm8(llvm::MCInst &Inst, unsigned Val,
2859                          uint64_t Address, const void *Decoder) {
2860   int imm = Val & 0xFF;
2861   if (Val == 0)
2862     imm = INT32_MIN;
2863   else if (!(Val & 0x100))
2864     imm *= -1;
2865   Inst.addOperand(MCOperand::CreateImm(imm));
2866 
2867   return MCDisassembler::Success;
2868 }
2869 
2870 
2871 static DecodeStatus DecodeT2AddrModeImm8(llvm::MCInst &Inst, unsigned Val,
2872                                  uint64_t Address, const void *Decoder) {
2873   DecodeStatus S = MCDisassembler::Success;
2874 
2875   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
2876   unsigned imm = fieldFromInstruction32(Val, 0, 9);
2877 
2878   // Some instructions always use an additive offset.
2879   switch (Inst.getOpcode()) {
2880     case ARM::t2LDRT:
2881     case ARM::t2LDRBT:
2882     case ARM::t2LDRHT:
2883     case ARM::t2LDRSBT:
2884     case ARM::t2LDRSHT:
2885     case ARM::t2STRT:
2886     case ARM::t2STRBT:
2887     case ARM::t2STRHT:
2888       imm |= 0x100;
2889       break;
2890     default:
2891       break;
2892   }
2893 
2894   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2895     return MCDisassembler::Fail;
2896   if (!Check(S, DecodeT2Imm8(Inst, imm, Address, Decoder)))
2897     return MCDisassembler::Fail;
2898 
2899   return S;
2900 }
2901 
2902 static DecodeStatus DecodeT2LdStPre(llvm::MCInst &Inst, unsigned Insn,
2903                                     uint64_t Address, const void *Decoder) {
2904   DecodeStatus S = MCDisassembler::Success;
2905 
2906   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2907   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2908   unsigned addr = fieldFromInstruction32(Insn, 0, 8);
2909   addr |= fieldFromInstruction32(Insn, 9, 1) << 8;
2910   addr |= Rn << 9;
2911   unsigned load = fieldFromInstruction32(Insn, 20, 1);
2912 
2913   if (!load) {
2914     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2915       return MCDisassembler::Fail;
2916   }
2917 
2918   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
2919     return MCDisassembler::Fail;
2920 
2921   if (load) {
2922     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2923       return MCDisassembler::Fail;
2924   }
2925 
2926   if (!Check(S, DecodeT2AddrModeImm8(Inst, addr, Address, Decoder)))
2927     return MCDisassembler::Fail;
2928 
2929   return S;
2930 }
2931 
2932 static DecodeStatus DecodeT2AddrModeImm12(llvm::MCInst &Inst, unsigned Val,
2933                                   uint64_t Address, const void *Decoder) {
2934   DecodeStatus S = MCDisassembler::Success;
2935 
2936   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
2937   unsigned imm = fieldFromInstruction32(Val, 0, 12);
2938 
2939   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2940     return MCDisassembler::Fail;
2941   Inst.addOperand(MCOperand::CreateImm(imm));
2942 
2943   return S;
2944 }
2945 
2946 
2947 static DecodeStatus DecodeThumbAddSPImm(llvm::MCInst &Inst, uint16_t Insn,
2948                                 uint64_t Address, const void *Decoder) {
2949   unsigned imm = fieldFromInstruction16(Insn, 0, 7);
2950 
2951   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2952   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2953   Inst.addOperand(MCOperand::CreateImm(imm));
2954 
2955   return MCDisassembler::Success;
2956 }
2957 
2958 static DecodeStatus DecodeThumbAddSPReg(llvm::MCInst &Inst, uint16_t Insn,
2959                                 uint64_t Address, const void *Decoder) {
2960   DecodeStatus S = MCDisassembler::Success;
2961 
2962   if (Inst.getOpcode() == ARM::tADDrSP) {
2963     unsigned Rdm = fieldFromInstruction16(Insn, 0, 3);
2964     Rdm |= fieldFromInstruction16(Insn, 7, 1) << 3;
2965 
2966     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
2967     return MCDisassembler::Fail;
2968     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
2969     return MCDisassembler::Fail;
2970     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2971   } else if (Inst.getOpcode() == ARM::tADDspr) {
2972     unsigned Rm = fieldFromInstruction16(Insn, 3, 4);
2973 
2974     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2975     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2976     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2977     return MCDisassembler::Fail;
2978   }
2979 
2980   return S;
2981 }
2982 
2983 static DecodeStatus DecodeThumbCPS(llvm::MCInst &Inst, uint16_t Insn,
2984                            uint64_t Address, const void *Decoder) {
2985   unsigned imod = fieldFromInstruction16(Insn, 4, 1) | 0x2;
2986   unsigned flags = fieldFromInstruction16(Insn, 0, 3);
2987 
2988   Inst.addOperand(MCOperand::CreateImm(imod));
2989   Inst.addOperand(MCOperand::CreateImm(flags));
2990 
2991   return MCDisassembler::Success;
2992 }
2993 
2994 static DecodeStatus DecodePostIdxReg(llvm::MCInst &Inst, unsigned Insn,
2995                              uint64_t Address, const void *Decoder) {
2996   DecodeStatus S = MCDisassembler::Success;
2997   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2998   unsigned add = fieldFromInstruction32(Insn, 4, 1);
2999 
3000   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3001     return MCDisassembler::Fail;
3002   Inst.addOperand(MCOperand::CreateImm(add));
3003 
3004   return S;
3005 }
3006 
3007 static DecodeStatus DecodeThumbBLXOffset(llvm::MCInst &Inst, unsigned Val,
3008                                  uint64_t Address, const void *Decoder) {
3009   if (!tryAddingSymbolicOperand(Address,
3010                                 (Address & ~2u) + SignExtend32<22>(Val << 1) + 4,
3011                                 true, 4, Inst, Decoder))
3012     Inst.addOperand(MCOperand::CreateImm(SignExtend32<22>(Val << 1)));
3013   return MCDisassembler::Success;
3014 }
3015 
3016 static DecodeStatus DecodeCoprocessor(llvm::MCInst &Inst, unsigned Val,
3017                               uint64_t Address, const void *Decoder) {
3018   if (Val == 0xA || Val == 0xB)
3019     return MCDisassembler::Fail;
3020 
3021   Inst.addOperand(MCOperand::CreateImm(Val));
3022   return MCDisassembler::Success;
3023 }
3024 
3025 static DecodeStatus
3026 DecodeThumbTableBranch(llvm::MCInst &Inst, unsigned Insn,
3027                        uint64_t Address, const void *Decoder) {
3028   DecodeStatus S = MCDisassembler::Success;
3029 
3030   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3031   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3032 
3033   if (Rn == ARM::SP) S = MCDisassembler::SoftFail;
3034   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3035     return MCDisassembler::Fail;
3036   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
3037     return MCDisassembler::Fail;
3038   return S;
3039 }
3040 
3041 static DecodeStatus
3042 DecodeThumb2BCCInstruction(llvm::MCInst &Inst, unsigned Insn,
3043                            uint64_t Address, const void *Decoder) {
3044   DecodeStatus S = MCDisassembler::Success;
3045 
3046   unsigned pred = fieldFromInstruction32(Insn, 22, 4);
3047   if (pred == 0xE || pred == 0xF) {
3048     unsigned opc = fieldFromInstruction32(Insn, 4, 28);
3049     switch (opc) {
3050       default:
3051         return MCDisassembler::Fail;
3052       case 0xf3bf8f4:
3053         Inst.setOpcode(ARM::t2DSB);
3054         break;
3055       case 0xf3bf8f5:
3056         Inst.setOpcode(ARM::t2DMB);
3057         break;
3058       case 0xf3bf8f6:
3059         Inst.setOpcode(ARM::t2ISB);
3060         break;
3061     }
3062 
3063     unsigned imm = fieldFromInstruction32(Insn, 0, 4);
3064     return DecodeMemBarrierOption(Inst, imm, Address, Decoder);
3065   }
3066 
3067   unsigned brtarget = fieldFromInstruction32(Insn, 0, 11) << 1;
3068   brtarget |= fieldFromInstruction32(Insn, 11, 1) << 19;
3069   brtarget |= fieldFromInstruction32(Insn, 13, 1) << 18;
3070   brtarget |= fieldFromInstruction32(Insn, 16, 6) << 12;
3071   brtarget |= fieldFromInstruction32(Insn, 26, 1) << 20;
3072 
3073   if (!Check(S, DecodeT2BROperand(Inst, brtarget, Address, Decoder)))
3074     return MCDisassembler::Fail;
3075   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3076     return MCDisassembler::Fail;
3077 
3078   return S;
3079 }
3080 
3081 // Decode a shifted immediate operand.  These basically consist
3082 // of an 8-bit value, and a 4-bit directive that specifies either
3083 // a splat operation or a rotation.
3084 static DecodeStatus DecodeT2SOImm(llvm::MCInst &Inst, unsigned Val,
3085                           uint64_t Address, const void *Decoder) {
3086   unsigned ctrl = fieldFromInstruction32(Val, 10, 2);
3087   if (ctrl == 0) {
3088     unsigned byte = fieldFromInstruction32(Val, 8, 2);
3089     unsigned imm = fieldFromInstruction32(Val, 0, 8);
3090     switch (byte) {
3091       case 0:
3092         Inst.addOperand(MCOperand::CreateImm(imm));
3093         break;
3094       case 1:
3095         Inst.addOperand(MCOperand::CreateImm((imm << 16) | imm));
3096         break;
3097       case 2:
3098         Inst.addOperand(MCOperand::CreateImm((imm << 24) | (imm << 8)));
3099         break;
3100       case 3:
3101         Inst.addOperand(MCOperand::CreateImm((imm << 24) | (imm << 16) |
3102                                              (imm << 8)  |  imm));
3103         break;
3104     }
3105   } else {
3106     unsigned unrot = fieldFromInstruction32(Val, 0, 7) | 0x80;
3107     unsigned rot = fieldFromInstruction32(Val, 7, 5);
3108     unsigned imm = (unrot >> rot) | (unrot << ((32-rot)&31));
3109     Inst.addOperand(MCOperand::CreateImm(imm));
3110   }
3111 
3112   return MCDisassembler::Success;
3113 }
3114 
3115 static DecodeStatus
3116 DecodeThumbBCCTargetOperand(llvm::MCInst &Inst, unsigned Val,
3117                             uint64_t Address, const void *Decoder){
3118   Inst.addOperand(MCOperand::CreateImm(Val << 1));
3119   return MCDisassembler::Success;
3120 }
3121 
3122 static DecodeStatus DecodeThumbBLTargetOperand(llvm::MCInst &Inst, unsigned Val,
3123                                        uint64_t Address, const void *Decoder){
3124   Inst.addOperand(MCOperand::CreateImm(SignExtend32<22>(Val << 1)));
3125   return MCDisassembler::Success;
3126 }
3127 
3128 static DecodeStatus DecodeMemBarrierOption(llvm::MCInst &Inst, unsigned Val,
3129                                    uint64_t Address, const void *Decoder) {
3130   switch (Val) {
3131   default:
3132     return MCDisassembler::Fail;
3133   case 0xF: // SY
3134   case 0xE: // ST
3135   case 0xB: // ISH
3136   case 0xA: // ISHST
3137   case 0x7: // NSH
3138   case 0x6: // NSHST
3139   case 0x3: // OSH
3140   case 0x2: // OSHST
3141     break;
3142   }
3143 
3144   Inst.addOperand(MCOperand::CreateImm(Val));
3145   return MCDisassembler::Success;
3146 }
3147 
3148 static DecodeStatus DecodeMSRMask(llvm::MCInst &Inst, unsigned Val,
3149                           uint64_t Address, const void *Decoder) {
3150   if (!Val) return MCDisassembler::Fail;
3151   Inst.addOperand(MCOperand::CreateImm(Val));
3152   return MCDisassembler::Success;
3153 }
3154 
3155 static DecodeStatus DecodeDoubleRegLoad(llvm::MCInst &Inst, unsigned Insn,
3156                                         uint64_t Address, const void *Decoder) {
3157   DecodeStatus S = MCDisassembler::Success;
3158 
3159   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3160   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3161   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3162 
3163   if ((Rt & 1) || Rt == 0xE || Rn == 0xF) return MCDisassembler::Fail;
3164 
3165   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3166     return MCDisassembler::Fail;
3167   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
3168     return MCDisassembler::Fail;
3169   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3170     return MCDisassembler::Fail;
3171   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3172     return MCDisassembler::Fail;
3173 
3174   return S;
3175 }
3176 
3177 
3178 static DecodeStatus DecodeDoubleRegStore(llvm::MCInst &Inst, unsigned Insn,
3179                                          uint64_t Address, const void *Decoder){
3180   DecodeStatus S = MCDisassembler::Success;
3181 
3182   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3183   unsigned Rt = fieldFromInstruction32(Insn, 0, 4);
3184   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3185   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3186 
3187   if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
3188     return MCDisassembler::Fail;
3189 
3190   if ((Rt & 1) || Rt == 0xE || Rn == 0xF) return MCDisassembler::Fail;
3191   if (Rd == Rn || Rd == Rt || Rd == Rt+1) return MCDisassembler::Fail;
3192 
3193   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3194     return MCDisassembler::Fail;
3195   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
3196     return MCDisassembler::Fail;
3197   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3198     return MCDisassembler::Fail;
3199   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3200     return MCDisassembler::Fail;
3201 
3202   return S;
3203 }
3204 
3205 static DecodeStatus DecodeLDRPreImm(llvm::MCInst &Inst, unsigned Insn,
3206                             uint64_t Address, const void *Decoder) {
3207   DecodeStatus S = MCDisassembler::Success;
3208 
3209   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3210   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3211   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3212   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3213   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3214   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3215 
3216   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3217 
3218   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3219     return MCDisassembler::Fail;
3220   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3221     return MCDisassembler::Fail;
3222   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
3223     return MCDisassembler::Fail;
3224   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3225     return MCDisassembler::Fail;
3226 
3227   return S;
3228 }
3229 
3230 static DecodeStatus DecodeLDRPreReg(llvm::MCInst &Inst, unsigned Insn,
3231                             uint64_t Address, const void *Decoder) {
3232   DecodeStatus S = MCDisassembler::Success;
3233 
3234   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3235   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3236   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3237   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3238   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3239   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3240   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3241 
3242   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3243   if (Rm == 0xF) S = MCDisassembler::SoftFail;
3244 
3245   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3246     return MCDisassembler::Fail;
3247   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3248     return MCDisassembler::Fail;
3249   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
3250     return MCDisassembler::Fail;
3251   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3252     return MCDisassembler::Fail;
3253 
3254   return S;
3255 }
3256 
3257 
3258 static DecodeStatus DecodeSTRPreImm(llvm::MCInst &Inst, unsigned Insn,
3259                             uint64_t Address, const void *Decoder) {
3260   DecodeStatus S = MCDisassembler::Success;
3261 
3262   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3263   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3264   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3265   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3266   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3267   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3268 
3269   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3270 
3271   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3272     return MCDisassembler::Fail;
3273   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3274     return MCDisassembler::Fail;
3275   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
3276     return MCDisassembler::Fail;
3277   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3278     return MCDisassembler::Fail;
3279 
3280   return S;
3281 }
3282 
3283 static DecodeStatus DecodeSTRPreReg(llvm::MCInst &Inst, unsigned Insn,
3284                             uint64_t Address, const void *Decoder) {
3285   DecodeStatus S = MCDisassembler::Success;
3286 
3287   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3288   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3289   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3290   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3291   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3292   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3293 
3294   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3295 
3296   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3297     return MCDisassembler::Fail;
3298   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3299     return MCDisassembler::Fail;
3300   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
3301     return MCDisassembler::Fail;
3302   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3303     return MCDisassembler::Fail;
3304 
3305   return S;
3306 }
3307 
3308 static DecodeStatus DecodeVLD1LN(llvm::MCInst &Inst, unsigned Insn,
3309                          uint64_t Address, const void *Decoder) {
3310   DecodeStatus S = MCDisassembler::Success;
3311 
3312   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3313   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3314   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3315   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3316   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3317 
3318   unsigned align = 0;
3319   unsigned index = 0;
3320   switch (size) {
3321     default:
3322       return MCDisassembler::Fail;
3323     case 0:
3324       if (fieldFromInstruction32(Insn, 4, 1))
3325         return MCDisassembler::Fail; // UNDEFINED
3326       index = fieldFromInstruction32(Insn, 5, 3);
3327       break;
3328     case 1:
3329       if (fieldFromInstruction32(Insn, 5, 1))
3330         return MCDisassembler::Fail; // UNDEFINED
3331       index = fieldFromInstruction32(Insn, 6, 2);
3332       if (fieldFromInstruction32(Insn, 4, 1))
3333         align = 2;
3334       break;
3335     case 2:
3336       if (fieldFromInstruction32(Insn, 6, 1))
3337         return MCDisassembler::Fail; // UNDEFINED
3338       index = fieldFromInstruction32(Insn, 7, 1);
3339       if (fieldFromInstruction32(Insn, 4, 2) != 0)
3340         align = 4;
3341   }
3342 
3343   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3344     return MCDisassembler::Fail;
3345   if (Rm != 0xF) { // Writeback
3346     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3347       return MCDisassembler::Fail;
3348   }
3349   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3350     return MCDisassembler::Fail;
3351   Inst.addOperand(MCOperand::CreateImm(align));
3352   if (Rm != 0xF) {
3353     if (Rm != 0xD) {
3354       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3355         return MCDisassembler::Fail;
3356     } else
3357       Inst.addOperand(MCOperand::CreateReg(0));
3358   }
3359 
3360   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3361     return MCDisassembler::Fail;
3362   Inst.addOperand(MCOperand::CreateImm(index));
3363 
3364   return S;
3365 }
3366 
3367 static DecodeStatus DecodeVST1LN(llvm::MCInst &Inst, unsigned Insn,
3368                          uint64_t Address, const void *Decoder) {
3369   DecodeStatus S = MCDisassembler::Success;
3370 
3371   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3372   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3373   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3374   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3375   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3376 
3377   unsigned align = 0;
3378   unsigned index = 0;
3379   switch (size) {
3380     default:
3381       return MCDisassembler::Fail;
3382     case 0:
3383       if (fieldFromInstruction32(Insn, 4, 1))
3384         return MCDisassembler::Fail; // UNDEFINED
3385       index = fieldFromInstruction32(Insn, 5, 3);
3386       break;
3387     case 1:
3388       if (fieldFromInstruction32(Insn, 5, 1))
3389         return MCDisassembler::Fail; // UNDEFINED
3390       index = fieldFromInstruction32(Insn, 6, 2);
3391       if (fieldFromInstruction32(Insn, 4, 1))
3392         align = 2;
3393       break;
3394     case 2:
3395       if (fieldFromInstruction32(Insn, 6, 1))
3396         return MCDisassembler::Fail; // UNDEFINED
3397       index = fieldFromInstruction32(Insn, 7, 1);
3398       if (fieldFromInstruction32(Insn, 4, 2) != 0)
3399         align = 4;
3400   }
3401 
3402   if (Rm != 0xF) { // Writeback
3403     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3404     return MCDisassembler::Fail;
3405   }
3406   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3407     return MCDisassembler::Fail;
3408   Inst.addOperand(MCOperand::CreateImm(align));
3409   if (Rm != 0xF) {
3410     if (Rm != 0xD) {
3411       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3412     return MCDisassembler::Fail;
3413     } else
3414       Inst.addOperand(MCOperand::CreateReg(0));
3415   }
3416 
3417   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3418     return MCDisassembler::Fail;
3419   Inst.addOperand(MCOperand::CreateImm(index));
3420 
3421   return S;
3422 }
3423 
3424 
3425 static DecodeStatus DecodeVLD2LN(llvm::MCInst &Inst, unsigned Insn,
3426                          uint64_t Address, const void *Decoder) {
3427   DecodeStatus S = MCDisassembler::Success;
3428 
3429   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3430   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3431   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3432   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3433   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3434 
3435   unsigned align = 0;
3436   unsigned index = 0;
3437   unsigned inc = 1;
3438   switch (size) {
3439     default:
3440       return MCDisassembler::Fail;
3441     case 0:
3442       index = fieldFromInstruction32(Insn, 5, 3);
3443       if (fieldFromInstruction32(Insn, 4, 1))
3444         align = 2;
3445       break;
3446     case 1:
3447       index = fieldFromInstruction32(Insn, 6, 2);
3448       if (fieldFromInstruction32(Insn, 4, 1))
3449         align = 4;
3450       if (fieldFromInstruction32(Insn, 5, 1))
3451         inc = 2;
3452       break;
3453     case 2:
3454       if (fieldFromInstruction32(Insn, 5, 1))
3455         return MCDisassembler::Fail; // UNDEFINED
3456       index = fieldFromInstruction32(Insn, 7, 1);
3457       if (fieldFromInstruction32(Insn, 4, 1) != 0)
3458         align = 8;
3459       if (fieldFromInstruction32(Insn, 6, 1))
3460         inc = 2;
3461       break;
3462   }
3463 
3464   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3465     return MCDisassembler::Fail;
3466   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3467     return MCDisassembler::Fail;
3468   if (Rm != 0xF) { // Writeback
3469     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3470       return MCDisassembler::Fail;
3471   }
3472   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3473     return MCDisassembler::Fail;
3474   Inst.addOperand(MCOperand::CreateImm(align));
3475   if (Rm != 0xF) {
3476     if (Rm != 0xD) {
3477       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3478         return MCDisassembler::Fail;
3479     } else
3480       Inst.addOperand(MCOperand::CreateReg(0));
3481   }
3482 
3483   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3484     return MCDisassembler::Fail;
3485   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3486     return MCDisassembler::Fail;
3487   Inst.addOperand(MCOperand::CreateImm(index));
3488 
3489   return S;
3490 }
3491 
3492 static DecodeStatus DecodeVST2LN(llvm::MCInst &Inst, unsigned Insn,
3493                          uint64_t Address, const void *Decoder) {
3494   DecodeStatus S = MCDisassembler::Success;
3495 
3496   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3497   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3498   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3499   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3500   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3501 
3502   unsigned align = 0;
3503   unsigned index = 0;
3504   unsigned inc = 1;
3505   switch (size) {
3506     default:
3507       return MCDisassembler::Fail;
3508     case 0:
3509       index = fieldFromInstruction32(Insn, 5, 3);
3510       if (fieldFromInstruction32(Insn, 4, 1))
3511         align = 2;
3512       break;
3513     case 1:
3514       index = fieldFromInstruction32(Insn, 6, 2);
3515       if (fieldFromInstruction32(Insn, 4, 1))
3516         align = 4;
3517       if (fieldFromInstruction32(Insn, 5, 1))
3518         inc = 2;
3519       break;
3520     case 2:
3521       if (fieldFromInstruction32(Insn, 5, 1))
3522         return MCDisassembler::Fail; // UNDEFINED
3523       index = fieldFromInstruction32(Insn, 7, 1);
3524       if (fieldFromInstruction32(Insn, 4, 1) != 0)
3525         align = 8;
3526       if (fieldFromInstruction32(Insn, 6, 1))
3527         inc = 2;
3528       break;
3529   }
3530 
3531   if (Rm != 0xF) { // Writeback
3532     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3533       return MCDisassembler::Fail;
3534   }
3535   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3536     return MCDisassembler::Fail;
3537   Inst.addOperand(MCOperand::CreateImm(align));
3538   if (Rm != 0xF) {
3539     if (Rm != 0xD) {
3540       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3541         return MCDisassembler::Fail;
3542     } else
3543       Inst.addOperand(MCOperand::CreateReg(0));
3544   }
3545 
3546   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3547     return MCDisassembler::Fail;
3548   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3549     return MCDisassembler::Fail;
3550   Inst.addOperand(MCOperand::CreateImm(index));
3551 
3552   return S;
3553 }
3554 
3555 
3556 static DecodeStatus DecodeVLD3LN(llvm::MCInst &Inst, unsigned Insn,
3557                          uint64_t Address, const void *Decoder) {
3558   DecodeStatus S = MCDisassembler::Success;
3559 
3560   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3561   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3562   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3563   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3564   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3565 
3566   unsigned align = 0;
3567   unsigned index = 0;
3568   unsigned inc = 1;
3569   switch (size) {
3570     default:
3571       return MCDisassembler::Fail;
3572     case 0:
3573       if (fieldFromInstruction32(Insn, 4, 1))
3574         return MCDisassembler::Fail; // UNDEFINED
3575       index = fieldFromInstruction32(Insn, 5, 3);
3576       break;
3577     case 1:
3578       if (fieldFromInstruction32(Insn, 4, 1))
3579         return MCDisassembler::Fail; // UNDEFINED
3580       index = fieldFromInstruction32(Insn, 6, 2);
3581       if (fieldFromInstruction32(Insn, 5, 1))
3582         inc = 2;
3583       break;
3584     case 2:
3585       if (fieldFromInstruction32(Insn, 4, 2))
3586         return MCDisassembler::Fail; // UNDEFINED
3587       index = fieldFromInstruction32(Insn, 7, 1);
3588       if (fieldFromInstruction32(Insn, 6, 1))
3589         inc = 2;
3590       break;
3591   }
3592 
3593   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3594     return MCDisassembler::Fail;
3595   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3596     return MCDisassembler::Fail;
3597   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3598     return MCDisassembler::Fail;
3599 
3600   if (Rm != 0xF) { // Writeback
3601     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3602     return MCDisassembler::Fail;
3603   }
3604   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3605     return MCDisassembler::Fail;
3606   Inst.addOperand(MCOperand::CreateImm(align));
3607   if (Rm != 0xF) {
3608     if (Rm != 0xD) {
3609       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3610     return MCDisassembler::Fail;
3611     } else
3612       Inst.addOperand(MCOperand::CreateReg(0));
3613   }
3614 
3615   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3616     return MCDisassembler::Fail;
3617   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3618     return MCDisassembler::Fail;
3619   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3620     return MCDisassembler::Fail;
3621   Inst.addOperand(MCOperand::CreateImm(index));
3622 
3623   return S;
3624 }
3625 
3626 static DecodeStatus DecodeVST3LN(llvm::MCInst &Inst, unsigned Insn,
3627                          uint64_t Address, const void *Decoder) {
3628   DecodeStatus S = MCDisassembler::Success;
3629 
3630   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3631   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3632   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3633   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3634   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3635 
3636   unsigned align = 0;
3637   unsigned index = 0;
3638   unsigned inc = 1;
3639   switch (size) {
3640     default:
3641       return MCDisassembler::Fail;
3642     case 0:
3643       if (fieldFromInstruction32(Insn, 4, 1))
3644         return MCDisassembler::Fail; // UNDEFINED
3645       index = fieldFromInstruction32(Insn, 5, 3);
3646       break;
3647     case 1:
3648       if (fieldFromInstruction32(Insn, 4, 1))
3649         return MCDisassembler::Fail; // UNDEFINED
3650       index = fieldFromInstruction32(Insn, 6, 2);
3651       if (fieldFromInstruction32(Insn, 5, 1))
3652         inc = 2;
3653       break;
3654     case 2:
3655       if (fieldFromInstruction32(Insn, 4, 2))
3656         return MCDisassembler::Fail; // UNDEFINED
3657       index = fieldFromInstruction32(Insn, 7, 1);
3658       if (fieldFromInstruction32(Insn, 6, 1))
3659         inc = 2;
3660       break;
3661   }
3662 
3663   if (Rm != 0xF) { // Writeback
3664     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3665     return MCDisassembler::Fail;
3666   }
3667   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3668     return MCDisassembler::Fail;
3669   Inst.addOperand(MCOperand::CreateImm(align));
3670   if (Rm != 0xF) {
3671     if (Rm != 0xD) {
3672       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3673     return MCDisassembler::Fail;
3674     } else
3675       Inst.addOperand(MCOperand::CreateReg(0));
3676   }
3677 
3678   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3679     return MCDisassembler::Fail;
3680   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3681     return MCDisassembler::Fail;
3682   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3683     return MCDisassembler::Fail;
3684   Inst.addOperand(MCOperand::CreateImm(index));
3685 
3686   return S;
3687 }
3688 
3689 
3690 static DecodeStatus DecodeVLD4LN(llvm::MCInst &Inst, unsigned Insn,
3691                          uint64_t Address, const void *Decoder) {
3692   DecodeStatus S = MCDisassembler::Success;
3693 
3694   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3695   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3696   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3697   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3698   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3699 
3700   unsigned align = 0;
3701   unsigned index = 0;
3702   unsigned inc = 1;
3703   switch (size) {
3704     default:
3705       return MCDisassembler::Fail;
3706     case 0:
3707       if (fieldFromInstruction32(Insn, 4, 1))
3708         align = 4;
3709       index = fieldFromInstruction32(Insn, 5, 3);
3710       break;
3711     case 1:
3712       if (fieldFromInstruction32(Insn, 4, 1))
3713         align = 8;
3714       index = fieldFromInstruction32(Insn, 6, 2);
3715       if (fieldFromInstruction32(Insn, 5, 1))
3716         inc = 2;
3717       break;
3718     case 2:
3719       if (fieldFromInstruction32(Insn, 4, 2))
3720         align = 4 << fieldFromInstruction32(Insn, 4, 2);
3721       index = fieldFromInstruction32(Insn, 7, 1);
3722       if (fieldFromInstruction32(Insn, 6, 1))
3723         inc = 2;
3724       break;
3725   }
3726 
3727   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3728     return MCDisassembler::Fail;
3729   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3730     return MCDisassembler::Fail;
3731   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3732     return MCDisassembler::Fail;
3733   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
3734     return MCDisassembler::Fail;
3735 
3736   if (Rm != 0xF) { // Writeback
3737     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3738       return MCDisassembler::Fail;
3739   }
3740   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3741     return MCDisassembler::Fail;
3742   Inst.addOperand(MCOperand::CreateImm(align));
3743   if (Rm != 0xF) {
3744     if (Rm != 0xD) {
3745       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3746         return MCDisassembler::Fail;
3747     } else
3748       Inst.addOperand(MCOperand::CreateReg(0));
3749   }
3750 
3751   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3752     return MCDisassembler::Fail;
3753   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3754     return MCDisassembler::Fail;
3755   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3756     return MCDisassembler::Fail;
3757   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
3758     return MCDisassembler::Fail;
3759   Inst.addOperand(MCOperand::CreateImm(index));
3760 
3761   return S;
3762 }
3763 
3764 static DecodeStatus DecodeVST4LN(llvm::MCInst &Inst, unsigned Insn,
3765                          uint64_t Address, const void *Decoder) {
3766   DecodeStatus S = MCDisassembler::Success;
3767 
3768   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3769   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3770   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3771   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3772   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3773 
3774   unsigned align = 0;
3775   unsigned index = 0;
3776   unsigned inc = 1;
3777   switch (size) {
3778     default:
3779       return MCDisassembler::Fail;
3780     case 0:
3781       if (fieldFromInstruction32(Insn, 4, 1))
3782         align = 4;
3783       index = fieldFromInstruction32(Insn, 5, 3);
3784       break;
3785     case 1:
3786       if (fieldFromInstruction32(Insn, 4, 1))
3787         align = 8;
3788       index = fieldFromInstruction32(Insn, 6, 2);
3789       if (fieldFromInstruction32(Insn, 5, 1))
3790         inc = 2;
3791       break;
3792     case 2:
3793       if (fieldFromInstruction32(Insn, 4, 2))
3794         align = 4 << fieldFromInstruction32(Insn, 4, 2);
3795       index = fieldFromInstruction32(Insn, 7, 1);
3796       if (fieldFromInstruction32(Insn, 6, 1))
3797         inc = 2;
3798       break;
3799   }
3800 
3801   if (Rm != 0xF) { // Writeback
3802     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3803     return MCDisassembler::Fail;
3804   }
3805   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3806     return MCDisassembler::Fail;
3807   Inst.addOperand(MCOperand::CreateImm(align));
3808   if (Rm != 0xF) {
3809     if (Rm != 0xD) {
3810       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3811     return MCDisassembler::Fail;
3812     } else
3813       Inst.addOperand(MCOperand::CreateReg(0));
3814   }
3815 
3816   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3817     return MCDisassembler::Fail;
3818   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3819     return MCDisassembler::Fail;
3820   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3821     return MCDisassembler::Fail;
3822   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
3823     return MCDisassembler::Fail;
3824   Inst.addOperand(MCOperand::CreateImm(index));
3825 
3826   return S;
3827 }
3828 
3829 static DecodeStatus DecodeVMOVSRR(llvm::MCInst &Inst, unsigned Insn,
3830                                   uint64_t Address, const void *Decoder) {
3831   DecodeStatus S = MCDisassembler::Success;
3832   unsigned Rt  = fieldFromInstruction32(Insn, 12, 4);
3833   unsigned Rt2 = fieldFromInstruction32(Insn, 16, 4);
3834   unsigned Rm  = fieldFromInstruction32(Insn,  0, 4);
3835   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3836   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
3837 
3838   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
3839     S = MCDisassembler::SoftFail;
3840 
3841   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
3842     return MCDisassembler::Fail;
3843   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
3844     return MCDisassembler::Fail;
3845   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
3846     return MCDisassembler::Fail;
3847   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
3848     return MCDisassembler::Fail;
3849   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3850     return MCDisassembler::Fail;
3851 
3852   return S;
3853 }
3854 
3855 static DecodeStatus DecodeVMOVRRS(llvm::MCInst &Inst, unsigned Insn,
3856                                   uint64_t Address, const void *Decoder) {
3857   DecodeStatus S = MCDisassembler::Success;
3858   unsigned Rt  = fieldFromInstruction32(Insn, 12, 4);
3859   unsigned Rt2 = fieldFromInstruction32(Insn, 16, 4);
3860   unsigned Rm  = fieldFromInstruction32(Insn,  0, 4);
3861   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3862   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
3863 
3864   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
3865     S = MCDisassembler::SoftFail;
3866 
3867   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
3868     return MCDisassembler::Fail;
3869   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
3870     return MCDisassembler::Fail;
3871   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
3872     return MCDisassembler::Fail;
3873   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
3874     return MCDisassembler::Fail;
3875   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3876     return MCDisassembler::Fail;
3877 
3878   return S;
3879 }
3880 
3881 static DecodeStatus DecodeIT(llvm::MCInst &Inst, unsigned Insn,
3882                              uint64_t Address, const void *Decoder) {
3883   DecodeStatus S = MCDisassembler::Success;
3884   unsigned pred = fieldFromInstruction16(Insn, 4, 4);
3885   // The InstPrinter needs to have the low bit of the predicate in
3886   // the mask operand to be able to print it properly.
3887   unsigned mask = fieldFromInstruction16(Insn, 0, 5);
3888 
3889   if (pred == 0xF) {
3890     pred = 0xE;
3891     S = MCDisassembler::SoftFail;
3892   }
3893 
3894   if ((mask & 0xF) == 0) {
3895     // Preserve the high bit of the mask, which is the low bit of
3896     // the predicate.
3897     mask &= 0x10;
3898     mask |= 0x8;
3899     S = MCDisassembler::SoftFail;
3900   }
3901 
3902   Inst.addOperand(MCOperand::CreateImm(pred));
3903   Inst.addOperand(MCOperand::CreateImm(mask));
3904   return S;
3905 }
3906 
3907 static DecodeStatus
3908 DecodeT2LDRDPreInstruction(llvm::MCInst &Inst, unsigned Insn,
3909                            uint64_t Address, const void *Decoder) {
3910   DecodeStatus S = MCDisassembler::Success;
3911 
3912   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3913   unsigned Rt2 = fieldFromInstruction32(Insn, 8, 4);
3914   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3915   unsigned addr = fieldFromInstruction32(Insn, 0, 8);
3916   unsigned W = fieldFromInstruction32(Insn, 21, 1);
3917   unsigned U = fieldFromInstruction32(Insn, 23, 1);
3918   unsigned P = fieldFromInstruction32(Insn, 24, 1);
3919   bool writeback = (W == 1) | (P == 0);
3920 
3921   addr |= (U << 8) | (Rn << 9);
3922 
3923   if (writeback && (Rn == Rt || Rn == Rt2))
3924     Check(S, MCDisassembler::SoftFail);
3925   if (Rt == Rt2)
3926     Check(S, MCDisassembler::SoftFail);
3927 
3928   // Rt
3929   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
3930     return MCDisassembler::Fail;
3931   // Rt2
3932   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
3933     return MCDisassembler::Fail;
3934   // Writeback operand
3935   if (!Check(S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
3936     return MCDisassembler::Fail;
3937   // addr
3938   if (!Check(S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
3939     return MCDisassembler::Fail;
3940 
3941   return S;
3942 }
3943 
3944 static DecodeStatus
3945 DecodeT2STRDPreInstruction(llvm::MCInst &Inst, unsigned Insn,
3946                            uint64_t Address, const void *Decoder) {
3947   DecodeStatus S = MCDisassembler::Success;
3948 
3949   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3950   unsigned Rt2 = fieldFromInstruction32(Insn, 8, 4);
3951   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3952   unsigned addr = fieldFromInstruction32(Insn, 0, 8);
3953   unsigned W = fieldFromInstruction32(Insn, 21, 1);
3954   unsigned U = fieldFromInstruction32(Insn, 23, 1);
3955   unsigned P = fieldFromInstruction32(Insn, 24, 1);
3956   bool writeback = (W == 1) | (P == 0);
3957 
3958   addr |= (U << 8) | (Rn << 9);
3959 
3960   if (writeback && (Rn == Rt || Rn == Rt2))
3961     Check(S, MCDisassembler::SoftFail);
3962 
3963   // Writeback operand
3964   if (!Check(S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
3965     return MCDisassembler::Fail;
3966   // Rt
3967   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
3968     return MCDisassembler::Fail;
3969   // Rt2
3970   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
3971     return MCDisassembler::Fail;
3972   // addr
3973   if (!Check(S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
3974     return MCDisassembler::Fail;
3975 
3976   return S;
3977 }
3978 
3979 static DecodeStatus DecodeT2Adr(llvm::MCInst &Inst, uint32_t Insn,
3980                                 uint64_t Address, const void *Decoder) {
3981   unsigned sign1 = fieldFromInstruction32(Insn, 21, 1);
3982   unsigned sign2 = fieldFromInstruction32(Insn, 23, 1);
3983   if (sign1 != sign2) return MCDisassembler::Fail;
3984 
3985   unsigned Val = fieldFromInstruction32(Insn, 0, 8);
3986   Val |= fieldFromInstruction32(Insn, 12, 3) << 8;
3987   Val |= fieldFromInstruction32(Insn, 26, 1) << 11;
3988   Val |= sign1 << 12;
3989   Inst.addOperand(MCOperand::CreateImm(SignExtend32<13>(Val)));
3990 
3991   return MCDisassembler::Success;
3992 }
3993 
3994 static DecodeStatus DecodeT2ShifterImmOperand(llvm::MCInst &Inst, uint32_t Val,
3995                                               uint64_t Address,
3996                                               const void *Decoder) {
3997   DecodeStatus S = MCDisassembler::Success;
3998 
3999   // Shift of "asr #32" is not allowed in Thumb2 mode.
4000   if (Val == 0x20) S = MCDisassembler::SoftFail;
4001   Inst.addOperand(MCOperand::CreateImm(Val));
4002   return S;
4003 }
4004 
4005 static DecodeStatus DecodeSwap(llvm::MCInst &Inst, unsigned Insn,
4006                                uint64_t Address, const void *Decoder) {
4007   unsigned Rt   = fieldFromInstruction32(Insn, 12, 4);
4008   unsigned Rt2  = fieldFromInstruction32(Insn, 0,  4);
4009   unsigned Rn   = fieldFromInstruction32(Insn, 16, 4);
4010   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
4011 
4012   if (pred == 0xF)
4013     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
4014 
4015   DecodeStatus S = MCDisassembler::Success;
4016   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
4017     return MCDisassembler::Fail;
4018   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt2, Address, Decoder)))
4019     return MCDisassembler::Fail;
4020   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
4021     return MCDisassembler::Fail;
4022   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4023     return MCDisassembler::Fail;
4024 
4025   return S;
4026 }
4027 
4028 static DecodeStatus DecodeVCVTD(llvm::MCInst &Inst, unsigned Insn,
4029                                 uint64_t Address, const void *Decoder) {
4030   unsigned Vd = (fieldFromInstruction32(Insn, 12, 4) << 0);
4031   Vd |= (fieldFromInstruction32(Insn, 22, 1) << 4);
4032   unsigned Vm = (fieldFromInstruction32(Insn, 0, 4) << 0);
4033   Vm |= (fieldFromInstruction32(Insn, 5, 1) << 4);
4034   unsigned imm = fieldFromInstruction32(Insn, 16, 6);
4035   unsigned cmode = fieldFromInstruction32(Insn, 8, 4);
4036 
4037   DecodeStatus S = MCDisassembler::Success;
4038 
4039   // VMOVv2f32 is ambiguous with these decodings.
4040   if (!(imm & 0x38) && cmode == 0xF) {
4041     Inst.setOpcode(ARM::VMOVv2f32);
4042     return DecodeNEONModImmInstruction(Inst, Insn, Address, Decoder);
4043   }
4044 
4045   if (!(imm & 0x20)) Check(S, MCDisassembler::SoftFail);
4046 
4047   if (!Check(S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)))
4048     return MCDisassembler::Fail;
4049   if (!Check(S, DecodeDPRRegisterClass(Inst, Vm, Address, Decoder)))
4050     return MCDisassembler::Fail;
4051   Inst.addOperand(MCOperand::CreateImm(64 - imm));
4052 
4053   return S;
4054 }
4055 
4056 static DecodeStatus DecodeVCVTQ(llvm::MCInst &Inst, unsigned Insn,
4057                                 uint64_t Address, const void *Decoder) {
4058   unsigned Vd = (fieldFromInstruction32(Insn, 12, 4) << 0);
4059   Vd |= (fieldFromInstruction32(Insn, 22, 1) << 4);
4060   unsigned Vm = (fieldFromInstruction32(Insn, 0, 4) << 0);
4061   Vm |= (fieldFromInstruction32(Insn, 5, 1) << 4);
4062   unsigned imm = fieldFromInstruction32(Insn, 16, 6);
4063   unsigned cmode = fieldFromInstruction32(Insn, 8, 4);
4064 
4065   DecodeStatus S = MCDisassembler::Success;
4066 
4067   // VMOVv4f32 is ambiguous with these decodings.
4068   if (!(imm & 0x38) && cmode == 0xF) {
4069     Inst.setOpcode(ARM::VMOVv4f32);
4070     return DecodeNEONModImmInstruction(Inst, Insn, Address, Decoder);
4071   }
4072 
4073   if (!(imm & 0x20)) Check(S, MCDisassembler::SoftFail);
4074 
4075   if (!Check(S, DecodeQPRRegisterClass(Inst, Vd, Address, Decoder)))
4076     return MCDisassembler::Fail;
4077   if (!Check(S, DecodeQPRRegisterClass(Inst, Vm, Address, Decoder)))
4078     return MCDisassembler::Fail;
4079   Inst.addOperand(MCOperand::CreateImm(64 - imm));
4080 
4081   return S;
4082 }
4083