xref: /llvm-project/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp (revision fad59dab62ae862ed44d8abb516dd629a16318a9)
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 "ARMRegisterInfo.h"
14 #include "ARMSubtarget.h"
15 #include "MCTargetDesc/ARMAddressingModes.h"
16 #include "MCTargetDesc/ARMMCExpr.h"
17 #include "MCTargetDesc/ARMBaseInfo.h"
18 #include "llvm/MC/EDInstInfo.h"
19 #include "llvm/MC/MCInst.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 DecodeVCVTImmOperand(llvm::MCInst &Inst, unsigned Val,
183                                uint64_t Address, const void *Decoder);
184 static DecodeStatus DecodeAddrMode6Operand(llvm::MCInst &Inst, unsigned Val,
185                                uint64_t Address, const void *Decoder);
186 static DecodeStatus DecodeVLDInstruction(llvm::MCInst &Inst, unsigned Val,
187                                uint64_t Address, const void *Decoder);
188 static DecodeStatus DecodeVSTInstruction(llvm::MCInst &Inst, unsigned Val,
189                                uint64_t Address, const void *Decoder);
190 static DecodeStatus DecodeVLD1DupInstruction(llvm::MCInst &Inst, unsigned Val,
191                                uint64_t Address, const void *Decoder);
192 static DecodeStatus DecodeVLD2DupInstruction(llvm::MCInst &Inst, unsigned Val,
193                                uint64_t Address, const void *Decoder);
194 static DecodeStatus DecodeVLD3DupInstruction(llvm::MCInst &Inst, unsigned Val,
195                                uint64_t Address, const void *Decoder);
196 static DecodeStatus DecodeVLD4DupInstruction(llvm::MCInst &Inst, unsigned Val,
197                                uint64_t Address, const void *Decoder);
198 static DecodeStatus DecodeNEONModImmInstruction(llvm::MCInst &Inst,unsigned Val,
199                                uint64_t Address, const void *Decoder);
200 static DecodeStatus DecodeVSHLMaxInstruction(llvm::MCInst &Inst, unsigned Val,
201                                uint64_t Address, const void *Decoder);
202 static DecodeStatus DecodeShiftRight8Imm(llvm::MCInst &Inst, unsigned Val,
203                                uint64_t Address, const void *Decoder);
204 static DecodeStatus DecodeShiftRight16Imm(llvm::MCInst &Inst, unsigned Val,
205                                uint64_t Address, const void *Decoder);
206 static DecodeStatus DecodeShiftRight32Imm(llvm::MCInst &Inst, unsigned Val,
207                                uint64_t Address, const void *Decoder);
208 static DecodeStatus DecodeShiftRight64Imm(llvm::MCInst &Inst, unsigned Val,
209                                uint64_t Address, const void *Decoder);
210 static DecodeStatus DecodeTBLInstruction(llvm::MCInst &Inst, unsigned Insn,
211                                uint64_t Address, const void *Decoder);
212 static DecodeStatus DecodePostIdxReg(llvm::MCInst &Inst, unsigned Insn,
213                                uint64_t Address, const void *Decoder);
214 static DecodeStatus DecodeCoprocessor(llvm::MCInst &Inst, unsigned Insn,
215                                uint64_t Address, const void *Decoder);
216 static DecodeStatus DecodeMemBarrierOption(llvm::MCInst &Inst, unsigned Insn,
217                                uint64_t Address, const void *Decoder);
218 static DecodeStatus DecodeMSRMask(llvm::MCInst &Inst, unsigned Insn,
219                                uint64_t Address, const void *Decoder);
220 static DecodeStatus DecodeDoubleRegLoad(llvm::MCInst &Inst, unsigned Insn,
221                                uint64_t Address, const void *Decoder);
222 static DecodeStatus DecodeDoubleRegStore(llvm::MCInst &Inst, unsigned Insn,
223                                uint64_t Address, const void *Decoder);
224 static DecodeStatus DecodeLDRPreImm(llvm::MCInst &Inst, unsigned Insn,
225                                uint64_t Address, const void *Decoder);
226 static DecodeStatus DecodeLDRPreReg(llvm::MCInst &Inst, unsigned Insn,
227                                uint64_t Address, const void *Decoder);
228 static DecodeStatus DecodeSTRPreImm(llvm::MCInst &Inst, unsigned Insn,
229                                uint64_t Address, const void *Decoder);
230 static DecodeStatus DecodeSTRPreReg(llvm::MCInst &Inst, unsigned Insn,
231                                uint64_t Address, const void *Decoder);
232 static DecodeStatus DecodeVLD1LN(llvm::MCInst &Inst, unsigned Insn,
233                                uint64_t Address, const void *Decoder);
234 static DecodeStatus DecodeVLD2LN(llvm::MCInst &Inst, unsigned Insn,
235                                uint64_t Address, const void *Decoder);
236 static DecodeStatus DecodeVLD3LN(llvm::MCInst &Inst, unsigned Insn,
237                                uint64_t Address, const void *Decoder);
238 static DecodeStatus DecodeVLD4LN(llvm::MCInst &Inst, unsigned Insn,
239                                uint64_t Address, const void *Decoder);
240 static DecodeStatus DecodeVST1LN(llvm::MCInst &Inst, unsigned Insn,
241                                uint64_t Address, const void *Decoder);
242 static DecodeStatus DecodeVST2LN(llvm::MCInst &Inst, unsigned Insn,
243                                uint64_t Address, const void *Decoder);
244 static DecodeStatus DecodeVST3LN(llvm::MCInst &Inst, unsigned Insn,
245                                uint64_t Address, const void *Decoder);
246 static DecodeStatus DecodeVST4LN(llvm::MCInst &Inst, unsigned Insn,
247                                uint64_t Address, const void *Decoder);
248 static DecodeStatus DecodeVMOVSRR(llvm::MCInst &Inst, unsigned Insn,
249                                uint64_t Address, const void *Decoder);
250 static DecodeStatus DecodeVMOVRRS(llvm::MCInst &Inst, unsigned Insn,
251                                uint64_t Address, const void *Decoder);
252 static DecodeStatus DecodeSwap(llvm::MCInst &Inst, unsigned Insn,
253                                uint64_t Address, const void *Decoder);
254 
255 static DecodeStatus DecodeThumbAddSpecialReg(llvm::MCInst &Inst, uint16_t Insn,
256                                uint64_t Address, const void *Decoder);
257 static DecodeStatus DecodeThumbBROperand(llvm::MCInst &Inst, unsigned Val,
258                                uint64_t Address, const void *Decoder);
259 static DecodeStatus DecodeT2BROperand(llvm::MCInst &Inst, unsigned Val,
260                                uint64_t Address, const void *Decoder);
261 static DecodeStatus DecodeThumbCmpBROperand(llvm::MCInst &Inst, unsigned Val,
262                                uint64_t Address, const void *Decoder);
263 static DecodeStatus DecodeThumbAddrModeRR(llvm::MCInst &Inst, unsigned Val,
264                                uint64_t Address, const void *Decoder);
265 static DecodeStatus DecodeThumbAddrModeIS(llvm::MCInst &Inst, unsigned Val,
266                                uint64_t Address, const void *Decoder);
267 static DecodeStatus DecodeThumbAddrModePC(llvm::MCInst &Inst, unsigned Val,
268                                uint64_t Address, const void *Decoder);
269 static DecodeStatus DecodeThumbAddrModeSP(llvm::MCInst &Inst, unsigned Val,
270                                uint64_t Address, const void *Decoder);
271 static DecodeStatus DecodeT2AddrModeSOReg(llvm::MCInst &Inst, unsigned Val,
272                                uint64_t Address, const void *Decoder);
273 static DecodeStatus DecodeT2LoadShift(llvm::MCInst &Inst, unsigned Val,
274                                uint64_t Address, const void *Decoder);
275 static DecodeStatus DecodeT2Imm8S4(llvm::MCInst &Inst, unsigned Val,
276                                uint64_t Address, const void *Decoder);
277 static DecodeStatus DecodeT2AddrModeImm8s4(llvm::MCInst &Inst, unsigned Val,
278                                uint64_t Address, const void *Decoder);
279 static DecodeStatus DecodeT2AddrModeImm0_1020s4(llvm::MCInst &Inst,unsigned Val,
280                                uint64_t Address, const void *Decoder);
281 static DecodeStatus DecodeT2Imm8(llvm::MCInst &Inst, unsigned Val,
282                                uint64_t Address, const void *Decoder);
283 static DecodeStatus DecodeT2AddrModeImm8(llvm::MCInst &Inst, unsigned Val,
284                                uint64_t Address, const void *Decoder);
285 static DecodeStatus DecodeThumbAddSPImm(llvm::MCInst &Inst, uint16_t Val,
286                                uint64_t Address, const void *Decoder);
287 static DecodeStatus DecodeThumbAddSPReg(llvm::MCInst &Inst, uint16_t Insn,
288                                 uint64_t Address, const void *Decoder);
289 static DecodeStatus DecodeThumbCPS(llvm::MCInst &Inst, uint16_t Insn,
290                                 uint64_t Address, const void *Decoder);
291 static DecodeStatus DecodeThumbBLXOffset(llvm::MCInst &Inst, unsigned Insn,
292                                 uint64_t Address, const void *Decoder);
293 static DecodeStatus DecodeT2AddrModeImm12(llvm::MCInst &Inst, unsigned Val,
294                                 uint64_t Address, const void *Decoder);
295 static DecodeStatus DecodeThumbTableBranch(llvm::MCInst &Inst, unsigned Val,
296                                 uint64_t Address, const void *Decoder);
297 static DecodeStatus DecodeThumb2BCCInstruction(llvm::MCInst &Inst, unsigned Val,
298                                 uint64_t Address, const void *Decoder);
299 static DecodeStatus DecodeT2SOImm(llvm::MCInst &Inst, unsigned Val,
300                                 uint64_t Address, const void *Decoder);
301 static DecodeStatus DecodeThumbBCCTargetOperand(llvm::MCInst &Inst,unsigned Val,
302                                 uint64_t Address, const void *Decoder);
303 static DecodeStatus DecodeThumbBLTargetOperand(llvm::MCInst &Inst, unsigned Val,
304                                 uint64_t Address, const void *Decoder);
305 static DecodeStatus DecodeIT(llvm::MCInst &Inst, unsigned Val,
306                                 uint64_t Address, const void *Decoder);
307 static DecodeStatus DecodeT2LDRDPreInstruction(llvm::MCInst &Inst,unsigned Insn,
308                                uint64_t Address, const void *Decoder);
309 static DecodeStatus DecodeT2STRDPreInstruction(llvm::MCInst &Inst,unsigned Insn,
310                                uint64_t Address, const void *Decoder);
311 static DecodeStatus DecodeT2Adr(llvm::MCInst &Inst, unsigned Val,
312                                 uint64_t Address, const void *Decoder);
313 static DecodeStatus DecodeT2LdStPre(llvm::MCInst &Inst, unsigned Val,
314                                 uint64_t Address, const void *Decoder);
315 static DecodeStatus DecodeT2ShifterImmOperand(llvm::MCInst &Inst, unsigned Val,
316                                 uint64_t Address, const void *Decoder);
317 
318 
319 
320 #include "ARMGenDisassemblerTables.inc"
321 #include "ARMGenInstrInfo.inc"
322 #include "ARMGenEDInfo.inc"
323 
324 static MCDisassembler *createARMDisassembler(const Target &T, const MCSubtargetInfo &STI) {
325   return new ARMDisassembler(STI);
326 }
327 
328 static MCDisassembler *createThumbDisassembler(const Target &T, const MCSubtargetInfo &STI) {
329   return new ThumbDisassembler(STI);
330 }
331 
332 EDInstInfo *ARMDisassembler::getEDInfo() const {
333   return instInfoARM;
334 }
335 
336 EDInstInfo *ThumbDisassembler::getEDInfo() const {
337   return instInfoARM;
338 }
339 
340 DecodeStatus ARMDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
341                                              const MemoryObject &Region,
342                                              uint64_t Address,
343                                              raw_ostream &os,
344                                              raw_ostream &cs) const {
345   CommentStream = &cs;
346 
347   uint8_t bytes[4];
348 
349   assert(!(STI.getFeatureBits() & ARM::ModeThumb) &&
350          "Asked to disassemble an ARM instruction but Subtarget is in Thumb mode!");
351 
352   // We want to read exactly 4 bytes of data.
353   if (Region.readBytes(Address, 4, (uint8_t*)bytes, NULL) == -1) {
354     Size = 0;
355     return MCDisassembler::Fail;
356   }
357 
358   // Encoded as a small-endian 32-bit word in the stream.
359   uint32_t insn = (bytes[3] << 24) |
360                   (bytes[2] << 16) |
361                   (bytes[1] <<  8) |
362                   (bytes[0] <<  0);
363 
364   // Calling the auto-generated decoder function.
365   DecodeStatus result = decodeARMInstruction32(MI, insn, Address, this, STI);
366   if (result != MCDisassembler::Fail) {
367     Size = 4;
368     return result;
369   }
370 
371   // VFP and NEON instructions, similarly, are shared between ARM
372   // and Thumb modes.
373   MI.clear();
374   result = decodeVFPInstruction32(MI, insn, Address, this, STI);
375   if (result != MCDisassembler::Fail) {
376     Size = 4;
377     return result;
378   }
379 
380   MI.clear();
381   result = decodeNEONDataInstruction32(MI, insn, Address, this, STI);
382   if (result != MCDisassembler::Fail) {
383     Size = 4;
384     // Add a fake predicate operand, because we share these instruction
385     // definitions with Thumb2 where these instructions are predicable.
386     if (!DecodePredicateOperand(MI, 0xE, Address, this))
387       return MCDisassembler::Fail;
388     return result;
389   }
390 
391   MI.clear();
392   result = decodeNEONLoadStoreInstruction32(MI, insn, Address, this, STI);
393   if (result != MCDisassembler::Fail) {
394     Size = 4;
395     // Add a fake predicate operand, because we share these instruction
396     // definitions with Thumb2 where these instructions are predicable.
397     if (!DecodePredicateOperand(MI, 0xE, Address, this))
398       return MCDisassembler::Fail;
399     return result;
400   }
401 
402   MI.clear();
403   result = decodeNEONDupInstruction32(MI, insn, Address, this, STI);
404   if (result != MCDisassembler::Fail) {
405     Size = 4;
406     // Add a fake predicate operand, because we share these instruction
407     // definitions with Thumb2 where these instructions are predicable.
408     if (!DecodePredicateOperand(MI, 0xE, Address, this))
409       return MCDisassembler::Fail;
410     return result;
411   }
412 
413   MI.clear();
414 
415   Size = 0;
416   return MCDisassembler::Fail;
417 }
418 
419 namespace llvm {
420 extern const MCInstrDesc ARMInsts[];
421 }
422 
423 /// tryAddingSymbolicOperand - trys to add a symbolic operand in place of the
424 /// immediate Value in the MCInst.  The immediate Value has had any PC
425 /// adjustment made by the caller.  If the instruction is a branch instruction
426 /// then isBranch is true, else false.  If the getOpInfo() function was set as
427 /// part of the setupForSymbolicDisassembly() call then that function is called
428 /// to get any symbolic information at the Address for this instruction.  If
429 /// that returns non-zero then the symbolic information it returns is used to
430 /// create an MCExpr and that is added as an operand to the MCInst.  If
431 /// getOpInfo() returns zero and isBranch is true then a symbol look up for
432 /// Value is done and if a symbol is found an MCExpr is created with that, else
433 /// an MCExpr with Value is created.  This function returns true if it adds an
434 /// operand to the MCInst and false otherwise.
435 static bool tryAddingSymbolicOperand(uint64_t Address, int32_t Value,
436                                      bool isBranch, uint64_t InstSize,
437                                      MCInst &MI, const void *Decoder) {
438   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
439   LLVMOpInfoCallback getOpInfo = Dis->getLLVMOpInfoCallback();
440   if (!getOpInfo)
441     return false;
442 
443   struct LLVMOpInfo1 SymbolicOp;
444   SymbolicOp.Value = Value;
445   void *DisInfo = Dis->getDisInfoBlock();
446   if (!getOpInfo(DisInfo, Address, 0 /* Offset */, InstSize, 1, &SymbolicOp)) {
447     if (isBranch) {
448       LLVMSymbolLookupCallback SymbolLookUp =
449                                             Dis->getLLVMSymbolLookupCallback();
450       if (SymbolLookUp) {
451         uint64_t ReferenceType;
452         ReferenceType = LLVMDisassembler_ReferenceType_In_Branch;
453         const char *ReferenceName;
454         const char *Name = SymbolLookUp(DisInfo, Value, &ReferenceType, Address,
455                                         &ReferenceName);
456         if (Name) {
457           SymbolicOp.AddSymbol.Name = Name;
458           SymbolicOp.AddSymbol.Present = true;
459           SymbolicOp.Value = 0;
460         }
461         else {
462           SymbolicOp.Value = Value;
463         }
464         if(ReferenceType == LLVMDisassembler_ReferenceType_Out_SymbolStub)
465           (*Dis->CommentStream) << "symbol stub for: " << ReferenceName;
466       }
467       else {
468         return false;
469       }
470     }
471     else {
472       return false;
473     }
474   }
475 
476   MCContext *Ctx = Dis->getMCContext();
477   const MCExpr *Add = NULL;
478   if (SymbolicOp.AddSymbol.Present) {
479     if (SymbolicOp.AddSymbol.Name) {
480       StringRef Name(SymbolicOp.AddSymbol.Name);
481       MCSymbol *Sym = Ctx->GetOrCreateSymbol(Name);
482       Add = MCSymbolRefExpr::Create(Sym, *Ctx);
483     } else {
484       Add = MCConstantExpr::Create(SymbolicOp.AddSymbol.Value, *Ctx);
485     }
486   }
487 
488   const MCExpr *Sub = NULL;
489   if (SymbolicOp.SubtractSymbol.Present) {
490     if (SymbolicOp.SubtractSymbol.Name) {
491       StringRef Name(SymbolicOp.SubtractSymbol.Name);
492       MCSymbol *Sym = Ctx->GetOrCreateSymbol(Name);
493       Sub = MCSymbolRefExpr::Create(Sym, *Ctx);
494     } else {
495       Sub = MCConstantExpr::Create(SymbolicOp.SubtractSymbol.Value, *Ctx);
496     }
497   }
498 
499   const MCExpr *Off = NULL;
500   if (SymbolicOp.Value != 0)
501     Off = MCConstantExpr::Create(SymbolicOp.Value, *Ctx);
502 
503   const MCExpr *Expr;
504   if (Sub) {
505     const MCExpr *LHS;
506     if (Add)
507       LHS = MCBinaryExpr::CreateSub(Add, Sub, *Ctx);
508     else
509       LHS = MCUnaryExpr::CreateMinus(Sub, *Ctx);
510     if (Off != 0)
511       Expr = MCBinaryExpr::CreateAdd(LHS, Off, *Ctx);
512     else
513       Expr = LHS;
514   } else if (Add) {
515     if (Off != 0)
516       Expr = MCBinaryExpr::CreateAdd(Add, Off, *Ctx);
517     else
518       Expr = Add;
519   } else {
520     if (Off != 0)
521       Expr = Off;
522     else
523       Expr = MCConstantExpr::Create(0, *Ctx);
524   }
525 
526   if (SymbolicOp.VariantKind == LLVMDisassembler_VariantKind_ARM_HI16)
527     MI.addOperand(MCOperand::CreateExpr(ARMMCExpr::CreateUpper16(Expr, *Ctx)));
528   else if (SymbolicOp.VariantKind == LLVMDisassembler_VariantKind_ARM_LO16)
529     MI.addOperand(MCOperand::CreateExpr(ARMMCExpr::CreateLower16(Expr, *Ctx)));
530   else if (SymbolicOp.VariantKind == LLVMDisassembler_VariantKind_None)
531     MI.addOperand(MCOperand::CreateExpr(Expr));
532   else
533     assert(0 && "bad SymbolicOp.VariantKind");
534 
535   return true;
536 }
537 
538 /// tryAddingPcLoadReferenceComment - trys to add a comment as to what is being
539 /// referenced by a load instruction with the base register that is the Pc.
540 /// These can often be values in a literal pool near the Address of the
541 /// instruction.  The Address of the instruction and its immediate Value are
542 /// used as a possible literal pool entry.  The SymbolLookUp call back will
543 /// return the name of a symbol referenced by the the literal pool's entry if
544 /// the referenced address is that of a symbol.  Or it will return a pointer to
545 /// a literal 'C' string if the referenced address of the literal pool's entry
546 /// is an address into a section with 'C' string literals.
547 static void tryAddingPcLoadReferenceComment(uint64_t Address, int Value,
548 					    const void *Decoder) {
549   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
550   LLVMSymbolLookupCallback SymbolLookUp = Dis->getLLVMSymbolLookupCallback();
551   if (SymbolLookUp) {
552     void *DisInfo = Dis->getDisInfoBlock();
553     uint64_t ReferenceType;
554     ReferenceType = LLVMDisassembler_ReferenceType_In_PCrel_Load;
555     const char *ReferenceName;
556     (void)SymbolLookUp(DisInfo, Value, &ReferenceType, Address, &ReferenceName);
557     if(ReferenceType == LLVMDisassembler_ReferenceType_Out_LitPool_SymAddr ||
558        ReferenceType == LLVMDisassembler_ReferenceType_Out_LitPool_CstrAddr)
559       (*Dis->CommentStream) << "literal pool for: " << ReferenceName;
560   }
561 }
562 
563 // Thumb1 instructions don't have explicit S bits.  Rather, they
564 // implicitly set CPSR.  Since it's not represented in the encoding, the
565 // auto-generated decoder won't inject the CPSR operand.  We need to fix
566 // that as a post-pass.
567 static void AddThumb1SBit(MCInst &MI, bool InITBlock) {
568   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
569   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
570   MCInst::iterator I = MI.begin();
571   for (unsigned i = 0; i < NumOps; ++i, ++I) {
572     if (I == MI.end()) break;
573     if (OpInfo[i].isOptionalDef() && OpInfo[i].RegClass == ARM::CCRRegClassID) {
574       if (i > 0 && OpInfo[i-1].isPredicate()) continue;
575       MI.insert(I, MCOperand::CreateReg(InITBlock ? 0 : ARM::CPSR));
576       return;
577     }
578   }
579 
580   MI.insert(I, MCOperand::CreateReg(InITBlock ? 0 : ARM::CPSR));
581 }
582 
583 // Most Thumb instructions don't have explicit predicates in the
584 // encoding, but rather get their predicates from IT context.  We need
585 // to fix up the predicate operands using this context information as a
586 // post-pass.
587 MCDisassembler::DecodeStatus
588 ThumbDisassembler::AddThumbPredicate(MCInst &MI) const {
589   MCDisassembler::DecodeStatus S = Success;
590 
591   // A few instructions actually have predicates encoded in them.  Don't
592   // try to overwrite it if we're seeing one of those.
593   switch (MI.getOpcode()) {
594     case ARM::tBcc:
595     case ARM::t2Bcc:
596     case ARM::tCBZ:
597     case ARM::tCBNZ:
598     case ARM::tCPS:
599     case ARM::t2CPS3p:
600     case ARM::t2CPS2p:
601     case ARM::t2CPS1p:
602     case ARM::tMOVSr:
603     case ARM::tSETEND:
604       // Some instructions (mostly conditional branches) are not
605       // allowed in IT blocks.
606       if (!ITBlock.empty())
607         S = SoftFail;
608       else
609         return Success;
610       break;
611     case ARM::tB:
612     case ARM::t2B:
613     case ARM::t2TBB:
614     case ARM::t2TBH:
615       // Some instructions (mostly unconditional branches) can
616       // only appears at the end of, or outside of, an IT.
617       if (ITBlock.size() > 1)
618         S = SoftFail;
619       break;
620     default:
621       break;
622   }
623 
624   // If we're in an IT block, base the predicate on that.  Otherwise,
625   // assume a predicate of AL.
626   unsigned CC;
627   if (!ITBlock.empty()) {
628     CC = ITBlock.back();
629     if (CC == 0xF)
630       CC = ARMCC::AL;
631     ITBlock.pop_back();
632   } else
633     CC = ARMCC::AL;
634 
635   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
636   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
637   MCInst::iterator I = MI.begin();
638   for (unsigned i = 0; i < NumOps; ++i, ++I) {
639     if (I == MI.end()) break;
640     if (OpInfo[i].isPredicate()) {
641       I = MI.insert(I, MCOperand::CreateImm(CC));
642       ++I;
643       if (CC == ARMCC::AL)
644         MI.insert(I, MCOperand::CreateReg(0));
645       else
646         MI.insert(I, MCOperand::CreateReg(ARM::CPSR));
647       return S;
648     }
649   }
650 
651   I = MI.insert(I, MCOperand::CreateImm(CC));
652   ++I;
653   if (CC == ARMCC::AL)
654     MI.insert(I, MCOperand::CreateReg(0));
655   else
656     MI.insert(I, MCOperand::CreateReg(ARM::CPSR));
657 
658   return S;
659 }
660 
661 // Thumb VFP instructions are a special case.  Because we share their
662 // encodings between ARM and Thumb modes, and they are predicable in ARM
663 // mode, the auto-generated decoder will give them an (incorrect)
664 // predicate operand.  We need to rewrite these operands based on the IT
665 // context as a post-pass.
666 void ThumbDisassembler::UpdateThumbVFPPredicate(MCInst &MI) const {
667   unsigned CC;
668   if (!ITBlock.empty()) {
669     CC = ITBlock.back();
670     ITBlock.pop_back();
671   } else
672     CC = ARMCC::AL;
673 
674   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
675   MCInst::iterator I = MI.begin();
676   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
677   for (unsigned i = 0; i < NumOps; ++i, ++I) {
678     if (OpInfo[i].isPredicate() ) {
679       I->setImm(CC);
680       ++I;
681       if (CC == ARMCC::AL)
682         I->setReg(0);
683       else
684         I->setReg(ARM::CPSR);
685       return;
686     }
687   }
688 }
689 
690 DecodeStatus ThumbDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
691                                                const MemoryObject &Region,
692                                                uint64_t Address,
693                                                raw_ostream &os,
694                                                raw_ostream &cs) const {
695   CommentStream = &cs;
696 
697   uint8_t bytes[4];
698 
699   assert((STI.getFeatureBits() & ARM::ModeThumb) &&
700          "Asked to disassemble in Thumb mode but Subtarget is in ARM mode!");
701 
702   // We want to read exactly 2 bytes of data.
703   if (Region.readBytes(Address, 2, (uint8_t*)bytes, NULL) == -1) {
704     Size = 0;
705     return MCDisassembler::Fail;
706   }
707 
708   uint16_t insn16 = (bytes[1] << 8) | bytes[0];
709   DecodeStatus result = decodeThumbInstruction16(MI, insn16, Address, this, STI);
710   if (result != MCDisassembler::Fail) {
711     Size = 2;
712     Check(result, AddThumbPredicate(MI));
713     return result;
714   }
715 
716   MI.clear();
717   result = decodeThumbSBitInstruction16(MI, insn16, Address, this, STI);
718   if (result) {
719     Size = 2;
720     bool InITBlock = !ITBlock.empty();
721     Check(result, AddThumbPredicate(MI));
722     AddThumb1SBit(MI, InITBlock);
723     return result;
724   }
725 
726   MI.clear();
727   result = decodeThumb2Instruction16(MI, insn16, Address, this, STI);
728   if (result != MCDisassembler::Fail) {
729     Size = 2;
730 
731     // Nested IT blocks are UNPREDICTABLE.  Must be checked before we add
732     // the Thumb predicate.
733     if (MI.getOpcode() == ARM::t2IT && !ITBlock.empty())
734       result = MCDisassembler::SoftFail;
735 
736     Check(result, AddThumbPredicate(MI));
737 
738     // If we find an IT instruction, we need to parse its condition
739     // code and mask operands so that we can apply them correctly
740     // to the subsequent instructions.
741     if (MI.getOpcode() == ARM::t2IT) {
742 
743       // (3 - the number of trailing zeros) is the number of then / else.
744       unsigned firstcond = MI.getOperand(0).getImm();
745       unsigned Mask = MI.getOperand(1).getImm();
746       unsigned CondBit0 = Mask >> 4 & 1;
747       unsigned NumTZ = CountTrailingZeros_32(Mask);
748       assert(NumTZ <= 3 && "Invalid IT mask!");
749       for (unsigned Pos = 3, e = NumTZ; Pos > e; --Pos) {
750         bool T = ((Mask >> Pos) & 1) == CondBit0;
751         if (T)
752           ITBlock.insert(ITBlock.begin(), firstcond);
753         else
754           ITBlock.insert(ITBlock.begin(), firstcond ^ 1);
755       }
756 
757       ITBlock.push_back(firstcond);
758     }
759 
760     return result;
761   }
762 
763   // We want to read exactly 4 bytes of data.
764   if (Region.readBytes(Address, 4, (uint8_t*)bytes, NULL) == -1) {
765     Size = 0;
766     return MCDisassembler::Fail;
767   }
768 
769   uint32_t insn32 = (bytes[3] <<  8) |
770                     (bytes[2] <<  0) |
771                     (bytes[1] << 24) |
772                     (bytes[0] << 16);
773   MI.clear();
774   result = decodeThumbInstruction32(MI, insn32, Address, this, STI);
775   if (result != MCDisassembler::Fail) {
776     Size = 4;
777     bool InITBlock = ITBlock.size();
778     Check(result, AddThumbPredicate(MI));
779     AddThumb1SBit(MI, InITBlock);
780     return result;
781   }
782 
783   MI.clear();
784   result = decodeThumb2Instruction32(MI, insn32, Address, this, STI);
785   if (result != MCDisassembler::Fail) {
786     Size = 4;
787     Check(result, AddThumbPredicate(MI));
788     return result;
789   }
790 
791   MI.clear();
792   result = decodeVFPInstruction32(MI, insn32, Address, this, STI);
793   if (result != MCDisassembler::Fail) {
794     Size = 4;
795     UpdateThumbVFPPredicate(MI);
796     return result;
797   }
798 
799   MI.clear();
800   result = decodeNEONDupInstruction32(MI, insn32, Address, this, STI);
801   if (result != MCDisassembler::Fail) {
802     Size = 4;
803     Check(result, AddThumbPredicate(MI));
804     return result;
805   }
806 
807   if (fieldFromInstruction32(insn32, 24, 8) == 0xF9) {
808     MI.clear();
809     uint32_t NEONLdStInsn = insn32;
810     NEONLdStInsn &= 0xF0FFFFFF;
811     NEONLdStInsn |= 0x04000000;
812     result = decodeNEONLoadStoreInstruction32(MI, NEONLdStInsn, Address, this, STI);
813     if (result != MCDisassembler::Fail) {
814       Size = 4;
815       Check(result, AddThumbPredicate(MI));
816       return result;
817     }
818   }
819 
820   if (fieldFromInstruction32(insn32, 24, 4) == 0xF) {
821     MI.clear();
822     uint32_t NEONDataInsn = insn32;
823     NEONDataInsn &= 0xF0FFFFFF; // Clear bits 27-24
824     NEONDataInsn |= (NEONDataInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
825     NEONDataInsn |= 0x12000000; // Set bits 28 and 25
826     result = decodeNEONDataInstruction32(MI, NEONDataInsn, Address, this, STI);
827     if (result != MCDisassembler::Fail) {
828       Size = 4;
829       Check(result, AddThumbPredicate(MI));
830       return result;
831     }
832   }
833 
834   Size = 0;
835   return MCDisassembler::Fail;
836 }
837 
838 
839 extern "C" void LLVMInitializeARMDisassembler() {
840   TargetRegistry::RegisterMCDisassembler(TheARMTarget,
841                                          createARMDisassembler);
842   TargetRegistry::RegisterMCDisassembler(TheThumbTarget,
843                                          createThumbDisassembler);
844 }
845 
846 static const unsigned GPRDecoderTable[] = {
847   ARM::R0, ARM::R1, ARM::R2, ARM::R3,
848   ARM::R4, ARM::R5, ARM::R6, ARM::R7,
849   ARM::R8, ARM::R9, ARM::R10, ARM::R11,
850   ARM::R12, ARM::SP, ARM::LR, ARM::PC
851 };
852 
853 static DecodeStatus DecodeGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
854                                    uint64_t Address, const void *Decoder) {
855   if (RegNo > 15)
856     return MCDisassembler::Fail;
857 
858   unsigned Register = GPRDecoderTable[RegNo];
859   Inst.addOperand(MCOperand::CreateReg(Register));
860   return MCDisassembler::Success;
861 }
862 
863 static DecodeStatus
864 DecodeGPRnopcRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
865                            uint64_t Address, const void *Decoder) {
866   if (RegNo == 15) return MCDisassembler::Fail;
867   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
868 }
869 
870 static DecodeStatus DecodetGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
871                                    uint64_t Address, const void *Decoder) {
872   if (RegNo > 7)
873     return MCDisassembler::Fail;
874   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
875 }
876 
877 static DecodeStatus DecodetcGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
878                                    uint64_t Address, const void *Decoder) {
879   unsigned Register = 0;
880   switch (RegNo) {
881     case 0:
882       Register = ARM::R0;
883       break;
884     case 1:
885       Register = ARM::R1;
886       break;
887     case 2:
888       Register = ARM::R2;
889       break;
890     case 3:
891       Register = ARM::R3;
892       break;
893     case 9:
894       Register = ARM::R9;
895       break;
896     case 12:
897       Register = ARM::R12;
898       break;
899     default:
900       return MCDisassembler::Fail;
901     }
902 
903   Inst.addOperand(MCOperand::CreateReg(Register));
904   return MCDisassembler::Success;
905 }
906 
907 static DecodeStatus DecoderGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
908                                    uint64_t Address, const void *Decoder) {
909   if (RegNo == 13 || RegNo == 15) return MCDisassembler::Fail;
910   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
911 }
912 
913 static const unsigned SPRDecoderTable[] = {
914      ARM::S0,  ARM::S1,  ARM::S2,  ARM::S3,
915      ARM::S4,  ARM::S5,  ARM::S6,  ARM::S7,
916      ARM::S8,  ARM::S9, ARM::S10, ARM::S11,
917     ARM::S12, ARM::S13, ARM::S14, ARM::S15,
918     ARM::S16, ARM::S17, ARM::S18, ARM::S19,
919     ARM::S20, ARM::S21, ARM::S22, ARM::S23,
920     ARM::S24, ARM::S25, ARM::S26, ARM::S27,
921     ARM::S28, ARM::S29, ARM::S30, ARM::S31
922 };
923 
924 static DecodeStatus DecodeSPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
925                                    uint64_t Address, const void *Decoder) {
926   if (RegNo > 31)
927     return MCDisassembler::Fail;
928 
929   unsigned Register = SPRDecoderTable[RegNo];
930   Inst.addOperand(MCOperand::CreateReg(Register));
931   return MCDisassembler::Success;
932 }
933 
934 static const unsigned DPRDecoderTable[] = {
935      ARM::D0,  ARM::D1,  ARM::D2,  ARM::D3,
936      ARM::D4,  ARM::D5,  ARM::D6,  ARM::D7,
937      ARM::D8,  ARM::D9, ARM::D10, ARM::D11,
938     ARM::D12, ARM::D13, ARM::D14, ARM::D15,
939     ARM::D16, ARM::D17, ARM::D18, ARM::D19,
940     ARM::D20, ARM::D21, ARM::D22, ARM::D23,
941     ARM::D24, ARM::D25, ARM::D26, ARM::D27,
942     ARM::D28, ARM::D29, ARM::D30, ARM::D31
943 };
944 
945 static DecodeStatus DecodeDPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
946                                    uint64_t Address, const void *Decoder) {
947   if (RegNo > 31)
948     return MCDisassembler::Fail;
949 
950   unsigned Register = DPRDecoderTable[RegNo];
951   Inst.addOperand(MCOperand::CreateReg(Register));
952   return MCDisassembler::Success;
953 }
954 
955 static DecodeStatus DecodeDPR_8RegisterClass(llvm::MCInst &Inst, unsigned RegNo,
956                                    uint64_t Address, const void *Decoder) {
957   if (RegNo > 7)
958     return MCDisassembler::Fail;
959   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
960 }
961 
962 static DecodeStatus
963 DecodeDPR_VFP2RegisterClass(llvm::MCInst &Inst, unsigned RegNo,
964                             uint64_t Address, const void *Decoder) {
965   if (RegNo > 15)
966     return MCDisassembler::Fail;
967   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
968 }
969 
970 static const unsigned QPRDecoderTable[] = {
971      ARM::Q0,  ARM::Q1,  ARM::Q2,  ARM::Q3,
972      ARM::Q4,  ARM::Q5,  ARM::Q6,  ARM::Q7,
973      ARM::Q8,  ARM::Q9, ARM::Q10, ARM::Q11,
974     ARM::Q12, ARM::Q13, ARM::Q14, ARM::Q15
975 };
976 
977 
978 static DecodeStatus DecodeQPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
979                                    uint64_t Address, const void *Decoder) {
980   if (RegNo > 31)
981     return MCDisassembler::Fail;
982   RegNo >>= 1;
983 
984   unsigned Register = QPRDecoderTable[RegNo];
985   Inst.addOperand(MCOperand::CreateReg(Register));
986   return MCDisassembler::Success;
987 }
988 
989 static DecodeStatus DecodePredicateOperand(llvm::MCInst &Inst, unsigned Val,
990                                uint64_t Address, const void *Decoder) {
991   if (Val == 0xF) return MCDisassembler::Fail;
992   // AL predicate is not allowed on Thumb1 branches.
993   if (Inst.getOpcode() == ARM::tBcc && Val == 0xE)
994     return MCDisassembler::Fail;
995   Inst.addOperand(MCOperand::CreateImm(Val));
996   if (Val == ARMCC::AL) {
997     Inst.addOperand(MCOperand::CreateReg(0));
998   } else
999     Inst.addOperand(MCOperand::CreateReg(ARM::CPSR));
1000   return MCDisassembler::Success;
1001 }
1002 
1003 static DecodeStatus DecodeCCOutOperand(llvm::MCInst &Inst, unsigned Val,
1004                                uint64_t Address, const void *Decoder) {
1005   if (Val)
1006     Inst.addOperand(MCOperand::CreateReg(ARM::CPSR));
1007   else
1008     Inst.addOperand(MCOperand::CreateReg(0));
1009   return MCDisassembler::Success;
1010 }
1011 
1012 static DecodeStatus DecodeSOImmOperand(llvm::MCInst &Inst, unsigned Val,
1013                                uint64_t Address, const void *Decoder) {
1014   uint32_t imm = Val & 0xFF;
1015   uint32_t rot = (Val & 0xF00) >> 7;
1016   uint32_t rot_imm = (imm >> rot) | (imm << ((32-rot) & 0x1F));
1017   Inst.addOperand(MCOperand::CreateImm(rot_imm));
1018   return MCDisassembler::Success;
1019 }
1020 
1021 static DecodeStatus DecodeSORegImmOperand(llvm::MCInst &Inst, unsigned Val,
1022                                uint64_t Address, const void *Decoder) {
1023   DecodeStatus S = MCDisassembler::Success;
1024 
1025   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
1026   unsigned type = fieldFromInstruction32(Val, 5, 2);
1027   unsigned imm = fieldFromInstruction32(Val, 7, 5);
1028 
1029   // Register-immediate
1030   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1031     return MCDisassembler::Fail;
1032 
1033   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
1034   switch (type) {
1035     case 0:
1036       Shift = ARM_AM::lsl;
1037       break;
1038     case 1:
1039       Shift = ARM_AM::lsr;
1040       break;
1041     case 2:
1042       Shift = ARM_AM::asr;
1043       break;
1044     case 3:
1045       Shift = ARM_AM::ror;
1046       break;
1047   }
1048 
1049   if (Shift == ARM_AM::ror && imm == 0)
1050     Shift = ARM_AM::rrx;
1051 
1052   unsigned Op = Shift | (imm << 3);
1053   Inst.addOperand(MCOperand::CreateImm(Op));
1054 
1055   return S;
1056 }
1057 
1058 static DecodeStatus DecodeSORegRegOperand(llvm::MCInst &Inst, unsigned Val,
1059                                uint64_t Address, const void *Decoder) {
1060   DecodeStatus S = MCDisassembler::Success;
1061 
1062   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
1063   unsigned type = fieldFromInstruction32(Val, 5, 2);
1064   unsigned Rs = fieldFromInstruction32(Val, 8, 4);
1065 
1066   // Register-register
1067   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1068     return MCDisassembler::Fail;
1069   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rs, Address, Decoder)))
1070     return MCDisassembler::Fail;
1071 
1072   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
1073   switch (type) {
1074     case 0:
1075       Shift = ARM_AM::lsl;
1076       break;
1077     case 1:
1078       Shift = ARM_AM::lsr;
1079       break;
1080     case 2:
1081       Shift = ARM_AM::asr;
1082       break;
1083     case 3:
1084       Shift = ARM_AM::ror;
1085       break;
1086   }
1087 
1088   Inst.addOperand(MCOperand::CreateImm(Shift));
1089 
1090   return S;
1091 }
1092 
1093 static DecodeStatus DecodeRegListOperand(llvm::MCInst &Inst, unsigned Val,
1094                                  uint64_t Address, const void *Decoder) {
1095   DecodeStatus S = MCDisassembler::Success;
1096 
1097   bool writebackLoad = false;
1098   unsigned writebackReg = 0;
1099   switch (Inst.getOpcode()) {
1100     default:
1101       break;
1102     case ARM::LDMIA_UPD:
1103     case ARM::LDMDB_UPD:
1104     case ARM::LDMIB_UPD:
1105     case ARM::LDMDA_UPD:
1106     case ARM::t2LDMIA_UPD:
1107     case ARM::t2LDMDB_UPD:
1108       writebackLoad = true;
1109       writebackReg = Inst.getOperand(0).getReg();
1110       break;
1111   }
1112 
1113   // Empty register lists are not allowed.
1114   uint32_t popcnt = CountPopulation_32(Val);
1115   if (popcnt == 0) return MCDisassembler::Fail;
1116   // and one-register lists are unpredictable.
1117   else if (popcnt == 1) Check(S, MCDisassembler::SoftFail);
1118 
1119   for (unsigned i = 0; i < 16; ++i) {
1120     if (Val & (1 << i)) {
1121       if (!Check(S, DecodeGPRRegisterClass(Inst, i, Address, Decoder)))
1122         return MCDisassembler::Fail;
1123       // Writeback not allowed if Rn is in the target list.
1124       if (writebackLoad && writebackReg == Inst.end()[-1].getReg())
1125         Check(S, MCDisassembler::SoftFail);
1126     }
1127   }
1128 
1129   return S;
1130 }
1131 
1132 static DecodeStatus DecodeSPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
1133                                  uint64_t Address, const void *Decoder) {
1134   DecodeStatus S = MCDisassembler::Success;
1135 
1136   unsigned Vd = fieldFromInstruction32(Val, 8, 4);
1137   unsigned regs = Val & 0xFF;
1138 
1139   if (!Check(S, DecodeSPRRegisterClass(Inst, Vd, Address, Decoder)))
1140     return MCDisassembler::Fail;
1141   for (unsigned i = 0; i < (regs - 1); ++i) {
1142     if (!Check(S, DecodeSPRRegisterClass(Inst, ++Vd, Address, Decoder)))
1143       return MCDisassembler::Fail;
1144   }
1145 
1146   return S;
1147 }
1148 
1149 static DecodeStatus DecodeDPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
1150                                  uint64_t Address, const void *Decoder) {
1151   DecodeStatus S = MCDisassembler::Success;
1152 
1153   unsigned Vd = fieldFromInstruction32(Val, 8, 4);
1154   unsigned regs = (Val & 0xFF) / 2;
1155 
1156   if (!Check(S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)))
1157       return MCDisassembler::Fail;
1158   for (unsigned i = 0; i < (regs - 1); ++i) {
1159     if (!Check(S, DecodeDPRRegisterClass(Inst, ++Vd, Address, Decoder)))
1160       return MCDisassembler::Fail;
1161   }
1162 
1163   return S;
1164 }
1165 
1166 static DecodeStatus DecodeBitfieldMaskOperand(llvm::MCInst &Inst, unsigned Val,
1167                                       uint64_t Address, const void *Decoder) {
1168   // This operand encodes a mask of contiguous zeros between a specified MSB
1169   // and LSB.  To decode it, we create the mask of all bits MSB-and-lower,
1170   // the mask of all bits LSB-and-lower, and then xor them to create
1171   // the mask of that's all ones on [msb, lsb].  Finally we not it to
1172   // create the final mask.
1173   unsigned msb = fieldFromInstruction32(Val, 5, 5);
1174   unsigned lsb = fieldFromInstruction32(Val, 0, 5);
1175 
1176   DecodeStatus S = MCDisassembler::Success;
1177   if (lsb > msb) Check(S, MCDisassembler::SoftFail);
1178 
1179   uint32_t msb_mask = 0xFFFFFFFF;
1180   if (msb != 31) msb_mask = (1U << (msb+1)) - 1;
1181   uint32_t lsb_mask = (1U << lsb) - 1;
1182 
1183   Inst.addOperand(MCOperand::CreateImm(~(msb_mask ^ lsb_mask)));
1184   return S;
1185 }
1186 
1187 static DecodeStatus DecodeCopMemInstruction(llvm::MCInst &Inst, unsigned Insn,
1188                                   uint64_t Address, const void *Decoder) {
1189   DecodeStatus S = MCDisassembler::Success;
1190 
1191   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1192   unsigned CRd = fieldFromInstruction32(Insn, 12, 4);
1193   unsigned coproc = fieldFromInstruction32(Insn, 8, 4);
1194   unsigned imm = fieldFromInstruction32(Insn, 0, 8);
1195   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1196   unsigned U = fieldFromInstruction32(Insn, 23, 1);
1197 
1198   switch (Inst.getOpcode()) {
1199     case ARM::LDC_OFFSET:
1200     case ARM::LDC_PRE:
1201     case ARM::LDC_POST:
1202     case ARM::LDC_OPTION:
1203     case ARM::LDCL_OFFSET:
1204     case ARM::LDCL_PRE:
1205     case ARM::LDCL_POST:
1206     case ARM::LDCL_OPTION:
1207     case ARM::STC_OFFSET:
1208     case ARM::STC_PRE:
1209     case ARM::STC_POST:
1210     case ARM::STC_OPTION:
1211     case ARM::STCL_OFFSET:
1212     case ARM::STCL_PRE:
1213     case ARM::STCL_POST:
1214     case ARM::STCL_OPTION:
1215     case ARM::t2LDC_OFFSET:
1216     case ARM::t2LDC_PRE:
1217     case ARM::t2LDC_POST:
1218     case ARM::t2LDC_OPTION:
1219     case ARM::t2LDCL_OFFSET:
1220     case ARM::t2LDCL_PRE:
1221     case ARM::t2LDCL_POST:
1222     case ARM::t2LDCL_OPTION:
1223     case ARM::t2STC_OFFSET:
1224     case ARM::t2STC_PRE:
1225     case ARM::t2STC_POST:
1226     case ARM::t2STC_OPTION:
1227     case ARM::t2STCL_OFFSET:
1228     case ARM::t2STCL_PRE:
1229     case ARM::t2STCL_POST:
1230     case ARM::t2STCL_OPTION:
1231       if (coproc == 0xA || coproc == 0xB)
1232         return MCDisassembler::Fail;
1233       break;
1234     default:
1235       break;
1236   }
1237 
1238   Inst.addOperand(MCOperand::CreateImm(coproc));
1239   Inst.addOperand(MCOperand::CreateImm(CRd));
1240   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1241     return MCDisassembler::Fail;
1242 
1243   switch (Inst.getOpcode()) {
1244     case ARM::t2LDC2_OFFSET:
1245     case ARM::t2LDC2L_OFFSET:
1246     case ARM::t2LDC2_PRE:
1247     case ARM::t2LDC2L_PRE:
1248     case ARM::t2STC2_OFFSET:
1249     case ARM::t2STC2L_OFFSET:
1250     case ARM::t2STC2_PRE:
1251     case ARM::t2STC2L_PRE:
1252     case ARM::LDC2_OFFSET:
1253     case ARM::LDC2L_OFFSET:
1254     case ARM::LDC2_PRE:
1255     case ARM::LDC2L_PRE:
1256     case ARM::STC2_OFFSET:
1257     case ARM::STC2L_OFFSET:
1258     case ARM::STC2_PRE:
1259     case ARM::STC2L_PRE:
1260     case ARM::t2LDC_OFFSET:
1261     case ARM::t2LDCL_OFFSET:
1262     case ARM::t2LDC_PRE:
1263     case ARM::t2LDCL_PRE:
1264     case ARM::t2STC_OFFSET:
1265     case ARM::t2STCL_OFFSET:
1266     case ARM::t2STC_PRE:
1267     case ARM::t2STCL_PRE:
1268     case ARM::LDC_OFFSET:
1269     case ARM::LDCL_OFFSET:
1270     case ARM::LDC_PRE:
1271     case ARM::LDCL_PRE:
1272     case ARM::STC_OFFSET:
1273     case ARM::STCL_OFFSET:
1274     case ARM::STC_PRE:
1275     case ARM::STCL_PRE:
1276       imm = ARM_AM::getAM5Opc(U ? ARM_AM::add : ARM_AM::sub, imm);
1277       Inst.addOperand(MCOperand::CreateImm(imm));
1278       break;
1279     case ARM::t2LDC2_POST:
1280     case ARM::t2LDC2L_POST:
1281     case ARM::t2STC2_POST:
1282     case ARM::t2STC2L_POST:
1283     case ARM::LDC2_POST:
1284     case ARM::LDC2L_POST:
1285     case ARM::STC2_POST:
1286     case ARM::STC2L_POST:
1287     case ARM::t2LDC_POST:
1288     case ARM::t2LDCL_POST:
1289     case ARM::t2STC_POST:
1290     case ARM::t2STCL_POST:
1291     case ARM::LDC_POST:
1292     case ARM::LDCL_POST:
1293     case ARM::STC_POST:
1294     case ARM::STCL_POST:
1295       imm |= U << 8;
1296       // fall through.
1297     default:
1298       // The 'option' variant doesn't encode 'U' in the immediate since
1299       // the immediate is unsigned [0,255].
1300       Inst.addOperand(MCOperand::CreateImm(imm));
1301       break;
1302   }
1303 
1304   switch (Inst.getOpcode()) {
1305     case ARM::LDC_OFFSET:
1306     case ARM::LDC_PRE:
1307     case ARM::LDC_POST:
1308     case ARM::LDC_OPTION:
1309     case ARM::LDCL_OFFSET:
1310     case ARM::LDCL_PRE:
1311     case ARM::LDCL_POST:
1312     case ARM::LDCL_OPTION:
1313     case ARM::STC_OFFSET:
1314     case ARM::STC_PRE:
1315     case ARM::STC_POST:
1316     case ARM::STC_OPTION:
1317     case ARM::STCL_OFFSET:
1318     case ARM::STCL_PRE:
1319     case ARM::STCL_POST:
1320     case ARM::STCL_OPTION:
1321       if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1322         return MCDisassembler::Fail;
1323       break;
1324     default:
1325       break;
1326   }
1327 
1328   return S;
1329 }
1330 
1331 static DecodeStatus
1332 DecodeAddrMode2IdxInstruction(llvm::MCInst &Inst, unsigned Insn,
1333                               uint64_t Address, const void *Decoder) {
1334   DecodeStatus S = MCDisassembler::Success;
1335 
1336   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1337   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
1338   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1339   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
1340   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1341   unsigned reg = fieldFromInstruction32(Insn, 25, 1);
1342   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1343   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1344 
1345   // On stores, the writeback operand precedes Rt.
1346   switch (Inst.getOpcode()) {
1347     case ARM::STR_POST_IMM:
1348     case ARM::STR_POST_REG:
1349     case ARM::STRB_POST_IMM:
1350     case ARM::STRB_POST_REG:
1351     case ARM::STRT_POST_REG:
1352     case ARM::STRT_POST_IMM:
1353     case ARM::STRBT_POST_REG:
1354     case ARM::STRBT_POST_IMM:
1355       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1356         return MCDisassembler::Fail;
1357       break;
1358     default:
1359       break;
1360   }
1361 
1362   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
1363     return MCDisassembler::Fail;
1364 
1365   // On loads, the writeback operand comes after Rt.
1366   switch (Inst.getOpcode()) {
1367     case ARM::LDR_POST_IMM:
1368     case ARM::LDR_POST_REG:
1369     case ARM::LDRB_POST_IMM:
1370     case ARM::LDRB_POST_REG:
1371     case ARM::LDRBT_POST_REG:
1372     case ARM::LDRBT_POST_IMM:
1373     case ARM::LDRT_POST_REG:
1374     case ARM::LDRT_POST_IMM:
1375       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1376         return MCDisassembler::Fail;
1377       break;
1378     default:
1379       break;
1380   }
1381 
1382   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1383     return MCDisassembler::Fail;
1384 
1385   ARM_AM::AddrOpc Op = ARM_AM::add;
1386   if (!fieldFromInstruction32(Insn, 23, 1))
1387     Op = ARM_AM::sub;
1388 
1389   bool writeback = (P == 0) || (W == 1);
1390   unsigned idx_mode = 0;
1391   if (P && writeback)
1392     idx_mode = ARMII::IndexModePre;
1393   else if (!P && writeback)
1394     idx_mode = ARMII::IndexModePost;
1395 
1396   if (writeback && (Rn == 15 || Rn == Rt))
1397     S = MCDisassembler::SoftFail; // UNPREDICTABLE
1398 
1399   if (reg) {
1400     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1401       return MCDisassembler::Fail;
1402     ARM_AM::ShiftOpc Opc = ARM_AM::lsl;
1403     switch( fieldFromInstruction32(Insn, 5, 2)) {
1404       case 0:
1405         Opc = ARM_AM::lsl;
1406         break;
1407       case 1:
1408         Opc = ARM_AM::lsr;
1409         break;
1410       case 2:
1411         Opc = ARM_AM::asr;
1412         break;
1413       case 3:
1414         Opc = ARM_AM::ror;
1415         break;
1416       default:
1417         return MCDisassembler::Fail;
1418     }
1419     unsigned amt = fieldFromInstruction32(Insn, 7, 5);
1420     unsigned imm = ARM_AM::getAM2Opc(Op, amt, Opc, idx_mode);
1421 
1422     Inst.addOperand(MCOperand::CreateImm(imm));
1423   } else {
1424     Inst.addOperand(MCOperand::CreateReg(0));
1425     unsigned tmp = ARM_AM::getAM2Opc(Op, imm, ARM_AM::lsl, idx_mode);
1426     Inst.addOperand(MCOperand::CreateImm(tmp));
1427   }
1428 
1429   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1430     return MCDisassembler::Fail;
1431 
1432   return S;
1433 }
1434 
1435 static DecodeStatus DecodeSORegMemOperand(llvm::MCInst &Inst, unsigned Val,
1436                                   uint64_t Address, const void *Decoder) {
1437   DecodeStatus S = MCDisassembler::Success;
1438 
1439   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
1440   unsigned Rm = fieldFromInstruction32(Val,  0, 4);
1441   unsigned type = fieldFromInstruction32(Val, 5, 2);
1442   unsigned imm = fieldFromInstruction32(Val, 7, 5);
1443   unsigned U = fieldFromInstruction32(Val, 12, 1);
1444 
1445   ARM_AM::ShiftOpc ShOp = ARM_AM::lsl;
1446   switch (type) {
1447     case 0:
1448       ShOp = ARM_AM::lsl;
1449       break;
1450     case 1:
1451       ShOp = ARM_AM::lsr;
1452       break;
1453     case 2:
1454       ShOp = ARM_AM::asr;
1455       break;
1456     case 3:
1457       ShOp = ARM_AM::ror;
1458       break;
1459   }
1460 
1461   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1462     return MCDisassembler::Fail;
1463   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1464     return MCDisassembler::Fail;
1465   unsigned shift;
1466   if (U)
1467     shift = ARM_AM::getAM2Opc(ARM_AM::add, imm, ShOp);
1468   else
1469     shift = ARM_AM::getAM2Opc(ARM_AM::sub, imm, ShOp);
1470   Inst.addOperand(MCOperand::CreateImm(shift));
1471 
1472   return S;
1473 }
1474 
1475 static DecodeStatus
1476 DecodeAddrMode3Instruction(llvm::MCInst &Inst, unsigned Insn,
1477                            uint64_t Address, const void *Decoder) {
1478   DecodeStatus S = MCDisassembler::Success;
1479 
1480   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
1481   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1482   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1483   unsigned type = fieldFromInstruction32(Insn, 22, 1);
1484   unsigned imm = fieldFromInstruction32(Insn, 8, 4);
1485   unsigned U = ((~fieldFromInstruction32(Insn, 23, 1)) & 1) << 8;
1486   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1487   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1488   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1489 
1490   bool writeback = (W == 1) | (P == 0);
1491 
1492   // For {LD,ST}RD, Rt must be even, else undefined.
1493   switch (Inst.getOpcode()) {
1494     case ARM::STRD:
1495     case ARM::STRD_PRE:
1496     case ARM::STRD_POST:
1497     case ARM::LDRD:
1498     case ARM::LDRD_PRE:
1499     case ARM::LDRD_POST:
1500       if (Rt & 0x1) return MCDisassembler::Fail;
1501       break;
1502     default:
1503       break;
1504   }
1505 
1506   if (writeback) { // Writeback
1507     if (P)
1508       U |= ARMII::IndexModePre << 9;
1509     else
1510       U |= ARMII::IndexModePost << 9;
1511 
1512     // On stores, the writeback operand precedes Rt.
1513     switch (Inst.getOpcode()) {
1514     case ARM::STRD:
1515     case ARM::STRD_PRE:
1516     case ARM::STRD_POST:
1517     case ARM::STRH:
1518     case ARM::STRH_PRE:
1519     case ARM::STRH_POST:
1520       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1521         return MCDisassembler::Fail;
1522       break;
1523     default:
1524       break;
1525     }
1526   }
1527 
1528   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
1529     return MCDisassembler::Fail;
1530   switch (Inst.getOpcode()) {
1531     case ARM::STRD:
1532     case ARM::STRD_PRE:
1533     case ARM::STRD_POST:
1534     case ARM::LDRD:
1535     case ARM::LDRD_PRE:
1536     case ARM::LDRD_POST:
1537       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
1538         return MCDisassembler::Fail;
1539       break;
1540     default:
1541       break;
1542   }
1543 
1544   if (writeback) {
1545     // On loads, the writeback operand comes after Rt.
1546     switch (Inst.getOpcode()) {
1547     case ARM::LDRD:
1548     case ARM::LDRD_PRE:
1549     case ARM::LDRD_POST:
1550     case ARM::LDRH:
1551     case ARM::LDRH_PRE:
1552     case ARM::LDRH_POST:
1553     case ARM::LDRSH:
1554     case ARM::LDRSH_PRE:
1555     case ARM::LDRSH_POST:
1556     case ARM::LDRSB:
1557     case ARM::LDRSB_PRE:
1558     case ARM::LDRSB_POST:
1559     case ARM::LDRHTr:
1560     case ARM::LDRSBTr:
1561       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1562         return MCDisassembler::Fail;
1563       break;
1564     default:
1565       break;
1566     }
1567   }
1568 
1569   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1570     return MCDisassembler::Fail;
1571 
1572   if (type) {
1573     Inst.addOperand(MCOperand::CreateReg(0));
1574     Inst.addOperand(MCOperand::CreateImm(U | (imm << 4) | Rm));
1575   } else {
1576     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1577     return MCDisassembler::Fail;
1578     Inst.addOperand(MCOperand::CreateImm(U));
1579   }
1580 
1581   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1582     return MCDisassembler::Fail;
1583 
1584   return S;
1585 }
1586 
1587 static DecodeStatus DecodeRFEInstruction(llvm::MCInst &Inst, unsigned Insn,
1588                                  uint64_t Address, const void *Decoder) {
1589   DecodeStatus S = MCDisassembler::Success;
1590 
1591   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1592   unsigned mode = fieldFromInstruction32(Insn, 23, 2);
1593 
1594   switch (mode) {
1595     case 0:
1596       mode = ARM_AM::da;
1597       break;
1598     case 1:
1599       mode = ARM_AM::ia;
1600       break;
1601     case 2:
1602       mode = ARM_AM::db;
1603       break;
1604     case 3:
1605       mode = ARM_AM::ib;
1606       break;
1607   }
1608 
1609   Inst.addOperand(MCOperand::CreateImm(mode));
1610   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1611     return MCDisassembler::Fail;
1612 
1613   return S;
1614 }
1615 
1616 static DecodeStatus DecodeMemMultipleWritebackInstruction(llvm::MCInst &Inst,
1617                                   unsigned Insn,
1618                                   uint64_t Address, const void *Decoder) {
1619   DecodeStatus S = MCDisassembler::Success;
1620 
1621   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1622   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1623   unsigned reglist = fieldFromInstruction32(Insn, 0, 16);
1624 
1625   if (pred == 0xF) {
1626     switch (Inst.getOpcode()) {
1627       case ARM::LDMDA:
1628         Inst.setOpcode(ARM::RFEDA);
1629         break;
1630       case ARM::LDMDA_UPD:
1631         Inst.setOpcode(ARM::RFEDA_UPD);
1632         break;
1633       case ARM::LDMDB:
1634         Inst.setOpcode(ARM::RFEDB);
1635         break;
1636       case ARM::LDMDB_UPD:
1637         Inst.setOpcode(ARM::RFEDB_UPD);
1638         break;
1639       case ARM::LDMIA:
1640         Inst.setOpcode(ARM::RFEIA);
1641         break;
1642       case ARM::LDMIA_UPD:
1643         Inst.setOpcode(ARM::RFEIA_UPD);
1644         break;
1645       case ARM::LDMIB:
1646         Inst.setOpcode(ARM::RFEIB);
1647         break;
1648       case ARM::LDMIB_UPD:
1649         Inst.setOpcode(ARM::RFEIB_UPD);
1650         break;
1651       case ARM::STMDA:
1652         Inst.setOpcode(ARM::SRSDA);
1653         break;
1654       case ARM::STMDA_UPD:
1655         Inst.setOpcode(ARM::SRSDA_UPD);
1656         break;
1657       case ARM::STMDB:
1658         Inst.setOpcode(ARM::SRSDB);
1659         break;
1660       case ARM::STMDB_UPD:
1661         Inst.setOpcode(ARM::SRSDB_UPD);
1662         break;
1663       case ARM::STMIA:
1664         Inst.setOpcode(ARM::SRSIA);
1665         break;
1666       case ARM::STMIA_UPD:
1667         Inst.setOpcode(ARM::SRSIA_UPD);
1668         break;
1669       case ARM::STMIB:
1670         Inst.setOpcode(ARM::SRSIB);
1671         break;
1672       case ARM::STMIB_UPD:
1673         Inst.setOpcode(ARM::SRSIB_UPD);
1674         break;
1675       default:
1676         if (!Check(S, MCDisassembler::Fail)) return MCDisassembler::Fail;
1677     }
1678 
1679     // For stores (which become SRS's, the only operand is the mode.
1680     if (fieldFromInstruction32(Insn, 20, 1) == 0) {
1681       Inst.addOperand(
1682           MCOperand::CreateImm(fieldFromInstruction32(Insn, 0, 4)));
1683       return S;
1684     }
1685 
1686     return DecodeRFEInstruction(Inst, Insn, Address, Decoder);
1687   }
1688 
1689   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1690     return MCDisassembler::Fail;
1691   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1692     return MCDisassembler::Fail; // Tied
1693   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1694     return MCDisassembler::Fail;
1695   if (!Check(S, DecodeRegListOperand(Inst, reglist, Address, Decoder)))
1696     return MCDisassembler::Fail;
1697 
1698   return S;
1699 }
1700 
1701 static DecodeStatus DecodeCPSInstruction(llvm::MCInst &Inst, unsigned Insn,
1702                                  uint64_t Address, const void *Decoder) {
1703   unsigned imod = fieldFromInstruction32(Insn, 18, 2);
1704   unsigned M = fieldFromInstruction32(Insn, 17, 1);
1705   unsigned iflags = fieldFromInstruction32(Insn, 6, 3);
1706   unsigned mode = fieldFromInstruction32(Insn, 0, 5);
1707 
1708   DecodeStatus S = MCDisassembler::Success;
1709 
1710   // imod == '01' --> UNPREDICTABLE
1711   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
1712   // return failure here.  The '01' imod value is unprintable, so there's
1713   // nothing useful we could do even if we returned UNPREDICTABLE.
1714 
1715   if (imod == 1) return MCDisassembler::Fail;
1716 
1717   if (imod && M) {
1718     Inst.setOpcode(ARM::CPS3p);
1719     Inst.addOperand(MCOperand::CreateImm(imod));
1720     Inst.addOperand(MCOperand::CreateImm(iflags));
1721     Inst.addOperand(MCOperand::CreateImm(mode));
1722   } else if (imod && !M) {
1723     Inst.setOpcode(ARM::CPS2p);
1724     Inst.addOperand(MCOperand::CreateImm(imod));
1725     Inst.addOperand(MCOperand::CreateImm(iflags));
1726     if (mode) S = MCDisassembler::SoftFail;
1727   } else if (!imod && M) {
1728     Inst.setOpcode(ARM::CPS1p);
1729     Inst.addOperand(MCOperand::CreateImm(mode));
1730     if (iflags) S = MCDisassembler::SoftFail;
1731   } else {
1732     // imod == '00' && M == '0' --> UNPREDICTABLE
1733     Inst.setOpcode(ARM::CPS1p);
1734     Inst.addOperand(MCOperand::CreateImm(mode));
1735     S = MCDisassembler::SoftFail;
1736   }
1737 
1738   return S;
1739 }
1740 
1741 static DecodeStatus DecodeT2CPSInstruction(llvm::MCInst &Inst, unsigned Insn,
1742                                  uint64_t Address, const void *Decoder) {
1743   unsigned imod = fieldFromInstruction32(Insn, 9, 2);
1744   unsigned M = fieldFromInstruction32(Insn, 8, 1);
1745   unsigned iflags = fieldFromInstruction32(Insn, 5, 3);
1746   unsigned mode = fieldFromInstruction32(Insn, 0, 5);
1747 
1748   DecodeStatus S = MCDisassembler::Success;
1749 
1750   // imod == '01' --> UNPREDICTABLE
1751   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
1752   // return failure here.  The '01' imod value is unprintable, so there's
1753   // nothing useful we could do even if we returned UNPREDICTABLE.
1754 
1755   if (imod == 1) return MCDisassembler::Fail;
1756 
1757   if (imod && M) {
1758     Inst.setOpcode(ARM::t2CPS3p);
1759     Inst.addOperand(MCOperand::CreateImm(imod));
1760     Inst.addOperand(MCOperand::CreateImm(iflags));
1761     Inst.addOperand(MCOperand::CreateImm(mode));
1762   } else if (imod && !M) {
1763     Inst.setOpcode(ARM::t2CPS2p);
1764     Inst.addOperand(MCOperand::CreateImm(imod));
1765     Inst.addOperand(MCOperand::CreateImm(iflags));
1766     if (mode) S = MCDisassembler::SoftFail;
1767   } else if (!imod && M) {
1768     Inst.setOpcode(ARM::t2CPS1p);
1769     Inst.addOperand(MCOperand::CreateImm(mode));
1770     if (iflags) S = MCDisassembler::SoftFail;
1771   } else {
1772     // imod == '00' && M == '0' --> UNPREDICTABLE
1773     Inst.setOpcode(ARM::t2CPS1p);
1774     Inst.addOperand(MCOperand::CreateImm(mode));
1775     S = MCDisassembler::SoftFail;
1776   }
1777 
1778   return S;
1779 }
1780 
1781 static DecodeStatus DecodeT2MOVTWInstruction(llvm::MCInst &Inst, unsigned Insn,
1782                                  uint64_t Address, const void *Decoder) {
1783   DecodeStatus S = MCDisassembler::Success;
1784 
1785   unsigned Rd = fieldFromInstruction32(Insn, 8, 4);
1786   unsigned imm = 0;
1787 
1788   imm |= (fieldFromInstruction32(Insn, 0, 8) << 0);
1789   imm |= (fieldFromInstruction32(Insn, 12, 3) << 8);
1790   imm |= (fieldFromInstruction32(Insn, 16, 4) << 12);
1791   imm |= (fieldFromInstruction32(Insn, 26, 1) << 11);
1792 
1793   if (Inst.getOpcode() == ARM::t2MOVTi16)
1794     if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
1795       return MCDisassembler::Fail;
1796   if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
1797     return MCDisassembler::Fail;
1798 
1799   if (!tryAddingSymbolicOperand(Address, imm, false, 4, Inst, Decoder))
1800     Inst.addOperand(MCOperand::CreateImm(imm));
1801 
1802   return S;
1803 }
1804 
1805 static DecodeStatus DecodeArmMOVTWInstruction(llvm::MCInst &Inst, unsigned Insn,
1806                                  uint64_t Address, const void *Decoder) {
1807   DecodeStatus S = MCDisassembler::Success;
1808 
1809   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
1810   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1811   unsigned imm = 0;
1812 
1813   imm |= (fieldFromInstruction32(Insn, 0, 12) << 0);
1814   imm |= (fieldFromInstruction32(Insn, 16, 4) << 12);
1815 
1816   if (Inst.getOpcode() == ARM::MOVTi16)
1817     if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
1818       return MCDisassembler::Fail;
1819   if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
1820     return MCDisassembler::Fail;
1821 
1822   if (!tryAddingSymbolicOperand(Address, imm, false, 4, Inst, Decoder))
1823     Inst.addOperand(MCOperand::CreateImm(imm));
1824 
1825   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1826     return MCDisassembler::Fail;
1827 
1828   return S;
1829 }
1830 
1831 static DecodeStatus DecodeSMLAInstruction(llvm::MCInst &Inst, unsigned Insn,
1832                                  uint64_t Address, const void *Decoder) {
1833   DecodeStatus S = MCDisassembler::Success;
1834 
1835   unsigned Rd = fieldFromInstruction32(Insn, 16, 4);
1836   unsigned Rn = fieldFromInstruction32(Insn, 0, 4);
1837   unsigned Rm = fieldFromInstruction32(Insn, 8, 4);
1838   unsigned Ra = fieldFromInstruction32(Insn, 12, 4);
1839   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1840 
1841   if (pred == 0xF)
1842     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
1843 
1844   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
1845     return MCDisassembler::Fail;
1846   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
1847     return MCDisassembler::Fail;
1848   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1849     return MCDisassembler::Fail;
1850   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Ra, Address, Decoder)))
1851     return MCDisassembler::Fail;
1852 
1853   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1854     return MCDisassembler::Fail;
1855 
1856   return S;
1857 }
1858 
1859 static DecodeStatus DecodeAddrModeImm12Operand(llvm::MCInst &Inst, unsigned Val,
1860                            uint64_t Address, const void *Decoder) {
1861   DecodeStatus S = MCDisassembler::Success;
1862 
1863   unsigned add = fieldFromInstruction32(Val, 12, 1);
1864   unsigned imm = fieldFromInstruction32(Val, 0, 12);
1865   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
1866 
1867   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1868     return MCDisassembler::Fail;
1869 
1870   if (!add) imm *= -1;
1871   if (imm == 0 && !add) imm = INT32_MIN;
1872   Inst.addOperand(MCOperand::CreateImm(imm));
1873   if (Rn == 15)
1874     tryAddingPcLoadReferenceComment(Address, Address + imm + 8, Decoder);
1875 
1876   return S;
1877 }
1878 
1879 static DecodeStatus DecodeAddrMode5Operand(llvm::MCInst &Inst, unsigned Val,
1880                                    uint64_t Address, const void *Decoder) {
1881   DecodeStatus S = MCDisassembler::Success;
1882 
1883   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
1884   unsigned U = fieldFromInstruction32(Val, 8, 1);
1885   unsigned imm = fieldFromInstruction32(Val, 0, 8);
1886 
1887   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1888     return MCDisassembler::Fail;
1889 
1890   if (U)
1891     Inst.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(ARM_AM::add, imm)));
1892   else
1893     Inst.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(ARM_AM::sub, imm)));
1894 
1895   return S;
1896 }
1897 
1898 static DecodeStatus DecodeAddrMode7Operand(llvm::MCInst &Inst, unsigned Val,
1899                                    uint64_t Address, const void *Decoder) {
1900   return DecodeGPRRegisterClass(Inst, Val, Address, Decoder);
1901 }
1902 
1903 static DecodeStatus
1904 DecodeBranchImmInstruction(llvm::MCInst &Inst, unsigned Insn,
1905                            uint64_t Address, const void *Decoder) {
1906   DecodeStatus S = MCDisassembler::Success;
1907 
1908   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1909   unsigned imm = fieldFromInstruction32(Insn, 0, 24) << 2;
1910 
1911   if (pred == 0xF) {
1912     Inst.setOpcode(ARM::BLXi);
1913     imm |= fieldFromInstruction32(Insn, 24, 1) << 1;
1914     Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(imm)));
1915     return S;
1916   }
1917 
1918   if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<26>(imm) + 8, true,
1919                                 4, Inst, Decoder))
1920     Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(imm)));
1921   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1922     return MCDisassembler::Fail;
1923 
1924   return S;
1925 }
1926 
1927 
1928 static DecodeStatus DecodeVCVTImmOperand(llvm::MCInst &Inst, unsigned Val,
1929                                  uint64_t Address, const void *Decoder) {
1930   Inst.addOperand(MCOperand::CreateImm(64 - Val));
1931   return MCDisassembler::Success;
1932 }
1933 
1934 static DecodeStatus DecodeAddrMode6Operand(llvm::MCInst &Inst, unsigned Val,
1935                                    uint64_t Address, const void *Decoder) {
1936   DecodeStatus S = MCDisassembler::Success;
1937 
1938   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
1939   unsigned align = fieldFromInstruction32(Val, 4, 2);
1940 
1941   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1942     return MCDisassembler::Fail;
1943   if (!align)
1944     Inst.addOperand(MCOperand::CreateImm(0));
1945   else
1946     Inst.addOperand(MCOperand::CreateImm(4 << align));
1947 
1948   return S;
1949 }
1950 
1951 static DecodeStatus DecodeVLDInstruction(llvm::MCInst &Inst, unsigned Insn,
1952                                    uint64_t Address, const void *Decoder) {
1953   DecodeStatus S = MCDisassembler::Success;
1954 
1955   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
1956   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
1957   unsigned wb = fieldFromInstruction32(Insn, 16, 4);
1958   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1959   Rn |= fieldFromInstruction32(Insn, 4, 2) << 4;
1960   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1961 
1962   // First output register
1963   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
1964     return MCDisassembler::Fail;
1965 
1966   // Second output register
1967   switch (Inst.getOpcode()) {
1968     case ARM::VLD3d8:
1969     case ARM::VLD3d16:
1970     case ARM::VLD3d32:
1971     case ARM::VLD3d8_UPD:
1972     case ARM::VLD3d16_UPD:
1973     case ARM::VLD3d32_UPD:
1974     case ARM::VLD4d8:
1975     case ARM::VLD4d16:
1976     case ARM::VLD4d32:
1977     case ARM::VLD4d8_UPD:
1978     case ARM::VLD4d16_UPD:
1979     case ARM::VLD4d32_UPD:
1980       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
1981         return MCDisassembler::Fail;
1982       break;
1983     case ARM::VLD3q8:
1984     case ARM::VLD3q16:
1985     case ARM::VLD3q32:
1986     case ARM::VLD3q8_UPD:
1987     case ARM::VLD3q16_UPD:
1988     case ARM::VLD3q32_UPD:
1989     case ARM::VLD4q8:
1990     case ARM::VLD4q16:
1991     case ARM::VLD4q32:
1992     case ARM::VLD4q8_UPD:
1993     case ARM::VLD4q16_UPD:
1994     case ARM::VLD4q32_UPD:
1995       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
1996         return MCDisassembler::Fail;
1997     default:
1998       break;
1999   }
2000 
2001   // Third output register
2002   switch(Inst.getOpcode()) {
2003     case ARM::VLD3d8:
2004     case ARM::VLD3d16:
2005     case ARM::VLD3d32:
2006     case ARM::VLD3d8_UPD:
2007     case ARM::VLD3d16_UPD:
2008     case ARM::VLD3d32_UPD:
2009     case ARM::VLD4d8:
2010     case ARM::VLD4d16:
2011     case ARM::VLD4d32:
2012     case ARM::VLD4d8_UPD:
2013     case ARM::VLD4d16_UPD:
2014     case ARM::VLD4d32_UPD:
2015       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2016         return MCDisassembler::Fail;
2017       break;
2018     case ARM::VLD3q8:
2019     case ARM::VLD3q16:
2020     case ARM::VLD3q32:
2021     case ARM::VLD3q8_UPD:
2022     case ARM::VLD3q16_UPD:
2023     case ARM::VLD3q32_UPD:
2024     case ARM::VLD4q8:
2025     case ARM::VLD4q16:
2026     case ARM::VLD4q32:
2027     case ARM::VLD4q8_UPD:
2028     case ARM::VLD4q16_UPD:
2029     case ARM::VLD4q32_UPD:
2030       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
2031         return MCDisassembler::Fail;
2032       break;
2033     default:
2034       break;
2035   }
2036 
2037   // Fourth output register
2038   switch (Inst.getOpcode()) {
2039     case ARM::VLD4d8:
2040     case ARM::VLD4d16:
2041     case ARM::VLD4d32:
2042     case ARM::VLD4d8_UPD:
2043     case ARM::VLD4d16_UPD:
2044     case ARM::VLD4d32_UPD:
2045       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
2046         return MCDisassembler::Fail;
2047       break;
2048     case ARM::VLD4q8:
2049     case ARM::VLD4q16:
2050     case ARM::VLD4q32:
2051     case ARM::VLD4q8_UPD:
2052     case ARM::VLD4q16_UPD:
2053     case ARM::VLD4q32_UPD:
2054       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
2055         return MCDisassembler::Fail;
2056       break;
2057     default:
2058       break;
2059   }
2060 
2061   // Writeback operand
2062   switch (Inst.getOpcode()) {
2063     case ARM::VLD1d8wb_fixed:
2064     case ARM::VLD1d16wb_fixed:
2065     case ARM::VLD1d32wb_fixed:
2066     case ARM::VLD1d64wb_fixed:
2067     case ARM::VLD1d8wb_register:
2068     case ARM::VLD1d16wb_register:
2069     case ARM::VLD1d32wb_register:
2070     case ARM::VLD1d64wb_register:
2071     case ARM::VLD1q8wb_fixed:
2072     case ARM::VLD1q16wb_fixed:
2073     case ARM::VLD1q32wb_fixed:
2074     case ARM::VLD1q64wb_fixed:
2075     case ARM::VLD1q8wb_register:
2076     case ARM::VLD1q16wb_register:
2077     case ARM::VLD1q32wb_register:
2078     case ARM::VLD1q64wb_register:
2079     case ARM::VLD1d8Twb_fixed:
2080     case ARM::VLD1d8Twb_register:
2081     case ARM::VLD1d16Twb_fixed:
2082     case ARM::VLD1d16Twb_register:
2083     case ARM::VLD1d32Twb_fixed:
2084     case ARM::VLD1d32Twb_register:
2085     case ARM::VLD1d64Twb_fixed:
2086     case ARM::VLD1d64Twb_register:
2087     case ARM::VLD1d8Qwb_fixed:
2088     case ARM::VLD1d8Qwb_register:
2089     case ARM::VLD1d16Qwb_fixed:
2090     case ARM::VLD1d16Qwb_register:
2091     case ARM::VLD1d32Qwb_fixed:
2092     case ARM::VLD1d32Qwb_register:
2093     case ARM::VLD1d64Qwb_fixed:
2094     case ARM::VLD1d64Qwb_register:
2095     case ARM::VLD2d8_UPD:
2096     case ARM::VLD2d16_UPD:
2097     case ARM::VLD2d32_UPD:
2098     case ARM::VLD2q8_UPD:
2099     case ARM::VLD2q16_UPD:
2100     case ARM::VLD2q32_UPD:
2101     case ARM::VLD2b8_UPD:
2102     case ARM::VLD2b16_UPD:
2103     case ARM::VLD2b32_UPD:
2104     case ARM::VLD3d8_UPD:
2105     case ARM::VLD3d16_UPD:
2106     case ARM::VLD3d32_UPD:
2107     case ARM::VLD3q8_UPD:
2108     case ARM::VLD3q16_UPD:
2109     case ARM::VLD3q32_UPD:
2110     case ARM::VLD4d8_UPD:
2111     case ARM::VLD4d16_UPD:
2112     case ARM::VLD4d32_UPD:
2113     case ARM::VLD4q8_UPD:
2114     case ARM::VLD4q16_UPD:
2115     case ARM::VLD4q32_UPD:
2116       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
2117         return MCDisassembler::Fail;
2118       break;
2119     default:
2120       break;
2121   }
2122 
2123   // AddrMode6 Base (register+alignment)
2124   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
2125     return MCDisassembler::Fail;
2126 
2127   // AddrMode6 Offset (register)
2128   switch (Inst.getOpcode()) {
2129   default:
2130     // The below have been updated to have explicit am6offset split
2131     // between fixed and register offset. For those instructions not
2132     // yet updated, we need to add an additional reg0 operand for the
2133     // fixed variant.
2134     //
2135     // The fixed offset encodes as Rm == 0xd, so we check for that.
2136     if (Rm == 0xd) {
2137       Inst.addOperand(MCOperand::CreateReg(0));
2138       break;
2139     }
2140     // Fall through to handle the register offset variant.
2141   case ARM::VLD1d8wb_fixed:
2142   case ARM::VLD1d16wb_fixed:
2143   case ARM::VLD1d32wb_fixed:
2144   case ARM::VLD1d64wb_fixed:
2145   case ARM::VLD1d8Twb_fixed:
2146   case ARM::VLD1d16Twb_fixed:
2147   case ARM::VLD1d32Twb_fixed:
2148   case ARM::VLD1d64Twb_fixed:
2149   case ARM::VLD1d8Qwb_fixed:
2150   case ARM::VLD1d16Qwb_fixed:
2151   case ARM::VLD1d32Qwb_fixed:
2152   case ARM::VLD1d64Qwb_fixed:
2153   case ARM::VLD1d8wb_register:
2154   case ARM::VLD1d16wb_register:
2155   case ARM::VLD1d32wb_register:
2156   case ARM::VLD1d64wb_register:
2157   case ARM::VLD1q8wb_fixed:
2158   case ARM::VLD1q16wb_fixed:
2159   case ARM::VLD1q32wb_fixed:
2160   case ARM::VLD1q64wb_fixed:
2161   case ARM::VLD1q8wb_register:
2162   case ARM::VLD1q16wb_register:
2163   case ARM::VLD1q32wb_register:
2164   case ARM::VLD1q64wb_register:
2165     // The fixed offset post-increment encodes Rm == 0xd. The no-writeback
2166     // variant encodes Rm == 0xf. Anything else is a register offset post-
2167     // increment and we need to add the register operand to the instruction.
2168     if (Rm != 0xD && Rm != 0xF &&
2169         !Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2170       return MCDisassembler::Fail;
2171     break;
2172   }
2173 
2174   return S;
2175 }
2176 
2177 static DecodeStatus DecodeVSTInstruction(llvm::MCInst &Inst, unsigned Insn,
2178                                  uint64_t Address, const void *Decoder) {
2179   DecodeStatus S = MCDisassembler::Success;
2180 
2181   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2182   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2183   unsigned wb = fieldFromInstruction32(Insn, 16, 4);
2184   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2185   Rn |= fieldFromInstruction32(Insn, 4, 2) << 4;
2186   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2187 
2188   // Writeback Operand
2189   switch (Inst.getOpcode()) {
2190     case ARM::VST1d8wb_fixed:
2191     case ARM::VST1d16wb_fixed:
2192     case ARM::VST1d32wb_fixed:
2193     case ARM::VST1d64wb_fixed:
2194     case ARM::VST1d8wb_register:
2195     case ARM::VST1d16wb_register:
2196     case ARM::VST1d32wb_register:
2197     case ARM::VST1d64wb_register:
2198     case ARM::VST1q8wb_fixed:
2199     case ARM::VST1q16wb_fixed:
2200     case ARM::VST1q32wb_fixed:
2201     case ARM::VST1q64wb_fixed:
2202     case ARM::VST1q8wb_register:
2203     case ARM::VST1q16wb_register:
2204     case ARM::VST1q32wb_register:
2205     case ARM::VST1q64wb_register:
2206     case ARM::VST1d8T_UPD:
2207     case ARM::VST1d16T_UPD:
2208     case ARM::VST1d32T_UPD:
2209     case ARM::VST1d64T_UPD:
2210     case ARM::VST1d8Q_UPD:
2211     case ARM::VST1d16Q_UPD:
2212     case ARM::VST1d32Q_UPD:
2213     case ARM::VST1d64Q_UPD:
2214     case ARM::VST2d8_UPD:
2215     case ARM::VST2d16_UPD:
2216     case ARM::VST2d32_UPD:
2217     case ARM::VST2q8_UPD:
2218     case ARM::VST2q16_UPD:
2219     case ARM::VST2q32_UPD:
2220     case ARM::VST2b8_UPD:
2221     case ARM::VST2b16_UPD:
2222     case ARM::VST2b32_UPD:
2223     case ARM::VST3d8_UPD:
2224     case ARM::VST3d16_UPD:
2225     case ARM::VST3d32_UPD:
2226     case ARM::VST3q8_UPD:
2227     case ARM::VST3q16_UPD:
2228     case ARM::VST3q32_UPD:
2229     case ARM::VST4d8_UPD:
2230     case ARM::VST4d16_UPD:
2231     case ARM::VST4d32_UPD:
2232     case ARM::VST4q8_UPD:
2233     case ARM::VST4q16_UPD:
2234     case ARM::VST4q32_UPD:
2235       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
2236         return MCDisassembler::Fail;
2237       break;
2238     default:
2239       break;
2240   }
2241 
2242   // AddrMode6 Base (register+alignment)
2243   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
2244     return MCDisassembler::Fail;
2245 
2246   // AddrMode6 Offset (register)
2247   switch (Inst.getOpcode()) {
2248     default:
2249       if (Rm == 0xD)
2250         Inst.addOperand(MCOperand::CreateReg(0));
2251       else if (Rm != 0xF) {
2252         if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2253           return MCDisassembler::Fail;
2254       }
2255       break;
2256     case ARM::VST1d8wb_fixed:
2257     case ARM::VST1d16wb_fixed:
2258     case ARM::VST1d32wb_fixed:
2259     case ARM::VST1d64wb_fixed:
2260     case ARM::VST1q8wb_fixed:
2261     case ARM::VST1q16wb_fixed:
2262     case ARM::VST1q32wb_fixed:
2263     case ARM::VST1q64wb_fixed:
2264       break;
2265   }
2266 
2267 
2268   // First input register
2269   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2270     return MCDisassembler::Fail;
2271 
2272   // Second input register
2273   switch (Inst.getOpcode()) {
2274     case ARM::VST1q8:
2275     case ARM::VST1q16:
2276     case ARM::VST1q32:
2277     case ARM::VST1q64:
2278     case ARM::VST1d8T:
2279     case ARM::VST1d16T:
2280     case ARM::VST1d32T:
2281     case ARM::VST1d64T:
2282     case ARM::VST1d8T_UPD:
2283     case ARM::VST1d16T_UPD:
2284     case ARM::VST1d32T_UPD:
2285     case ARM::VST1d64T_UPD:
2286     case ARM::VST1d8Q:
2287     case ARM::VST1d16Q:
2288     case ARM::VST1d32Q:
2289     case ARM::VST1d64Q:
2290     case ARM::VST1d8Q_UPD:
2291     case ARM::VST1d16Q_UPD:
2292     case ARM::VST1d32Q_UPD:
2293     case ARM::VST1d64Q_UPD:
2294     case ARM::VST2d8:
2295     case ARM::VST2d16:
2296     case ARM::VST2d32:
2297     case ARM::VST2d8_UPD:
2298     case ARM::VST2d16_UPD:
2299     case ARM::VST2d32_UPD:
2300     case ARM::VST2q8:
2301     case ARM::VST2q16:
2302     case ARM::VST2q32:
2303     case ARM::VST2q8_UPD:
2304     case ARM::VST2q16_UPD:
2305     case ARM::VST2q32_UPD:
2306     case ARM::VST3d8:
2307     case ARM::VST3d16:
2308     case ARM::VST3d32:
2309     case ARM::VST3d8_UPD:
2310     case ARM::VST3d16_UPD:
2311     case ARM::VST3d32_UPD:
2312     case ARM::VST4d8:
2313     case ARM::VST4d16:
2314     case ARM::VST4d32:
2315     case ARM::VST4d8_UPD:
2316     case ARM::VST4d16_UPD:
2317     case ARM::VST4d32_UPD:
2318       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
2319         return MCDisassembler::Fail;
2320       break;
2321     case ARM::VST2b8:
2322     case ARM::VST2b16:
2323     case ARM::VST2b32:
2324     case ARM::VST2b8_UPD:
2325     case ARM::VST2b16_UPD:
2326     case ARM::VST2b32_UPD:
2327     case ARM::VST3q8:
2328     case ARM::VST3q16:
2329     case ARM::VST3q32:
2330     case ARM::VST3q8_UPD:
2331     case ARM::VST3q16_UPD:
2332     case ARM::VST3q32_UPD:
2333     case ARM::VST4q8:
2334     case ARM::VST4q16:
2335     case ARM::VST4q32:
2336     case ARM::VST4q8_UPD:
2337     case ARM::VST4q16_UPD:
2338     case ARM::VST4q32_UPD:
2339       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2340         return MCDisassembler::Fail;
2341       break;
2342     default:
2343       break;
2344   }
2345 
2346   // Third input register
2347   switch (Inst.getOpcode()) {
2348     case ARM::VST1d8T:
2349     case ARM::VST1d16T:
2350     case ARM::VST1d32T:
2351     case ARM::VST1d64T:
2352     case ARM::VST1d8T_UPD:
2353     case ARM::VST1d16T_UPD:
2354     case ARM::VST1d32T_UPD:
2355     case ARM::VST1d64T_UPD:
2356     case ARM::VST1d8Q:
2357     case ARM::VST1d16Q:
2358     case ARM::VST1d32Q:
2359     case ARM::VST1d64Q:
2360     case ARM::VST1d8Q_UPD:
2361     case ARM::VST1d16Q_UPD:
2362     case ARM::VST1d32Q_UPD:
2363     case ARM::VST1d64Q_UPD:
2364     case ARM::VST2q8:
2365     case ARM::VST2q16:
2366     case ARM::VST2q32:
2367     case ARM::VST2q8_UPD:
2368     case ARM::VST2q16_UPD:
2369     case ARM::VST2q32_UPD:
2370     case ARM::VST3d8:
2371     case ARM::VST3d16:
2372     case ARM::VST3d32:
2373     case ARM::VST3d8_UPD:
2374     case ARM::VST3d16_UPD:
2375     case ARM::VST3d32_UPD:
2376     case ARM::VST4d8:
2377     case ARM::VST4d16:
2378     case ARM::VST4d32:
2379     case ARM::VST4d8_UPD:
2380     case ARM::VST4d16_UPD:
2381     case ARM::VST4d32_UPD:
2382       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2383         return MCDisassembler::Fail;
2384       break;
2385     case ARM::VST3q8:
2386     case ARM::VST3q16:
2387     case ARM::VST3q32:
2388     case ARM::VST3q8_UPD:
2389     case ARM::VST3q16_UPD:
2390     case ARM::VST3q32_UPD:
2391     case ARM::VST4q8:
2392     case ARM::VST4q16:
2393     case ARM::VST4q32:
2394     case ARM::VST4q8_UPD:
2395     case ARM::VST4q16_UPD:
2396     case ARM::VST4q32_UPD:
2397       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
2398         return MCDisassembler::Fail;
2399       break;
2400     default:
2401       break;
2402   }
2403 
2404   // Fourth input register
2405   switch (Inst.getOpcode()) {
2406     case ARM::VST1d8Q:
2407     case ARM::VST1d16Q:
2408     case ARM::VST1d32Q:
2409     case ARM::VST1d64Q:
2410     case ARM::VST1d8Q_UPD:
2411     case ARM::VST1d16Q_UPD:
2412     case ARM::VST1d32Q_UPD:
2413     case ARM::VST1d64Q_UPD:
2414     case ARM::VST2q8:
2415     case ARM::VST2q16:
2416     case ARM::VST2q32:
2417     case ARM::VST2q8_UPD:
2418     case ARM::VST2q16_UPD:
2419     case ARM::VST2q32_UPD:
2420     case ARM::VST4d8:
2421     case ARM::VST4d16:
2422     case ARM::VST4d32:
2423     case ARM::VST4d8_UPD:
2424     case ARM::VST4d16_UPD:
2425     case ARM::VST4d32_UPD:
2426       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
2427         return MCDisassembler::Fail;
2428       break;
2429     case ARM::VST4q8:
2430     case ARM::VST4q16:
2431     case ARM::VST4q32:
2432     case ARM::VST4q8_UPD:
2433     case ARM::VST4q16_UPD:
2434     case ARM::VST4q32_UPD:
2435       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
2436         return MCDisassembler::Fail;
2437       break;
2438     default:
2439       break;
2440   }
2441 
2442   return S;
2443 }
2444 
2445 static DecodeStatus DecodeVLD1DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2446                                     uint64_t Address, const void *Decoder) {
2447   DecodeStatus S = MCDisassembler::Success;
2448 
2449   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2450   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2451   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2452   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2453   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2454   unsigned size = fieldFromInstruction32(Insn, 6, 2);
2455   unsigned regs = fieldFromInstruction32(Insn, 5, 1) + 1;
2456 
2457   align *= (1 << size);
2458 
2459   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2460     return MCDisassembler::Fail;
2461   if (regs == 2) {
2462     if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
2463       return MCDisassembler::Fail;
2464   }
2465   if (Rm != 0xF) {
2466     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2467       return MCDisassembler::Fail;
2468   }
2469 
2470   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2471     return MCDisassembler::Fail;
2472   Inst.addOperand(MCOperand::CreateImm(align));
2473 
2474   if (Rm == 0xD)
2475     Inst.addOperand(MCOperand::CreateReg(0));
2476   else if (Rm != 0xF) {
2477     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2478       return MCDisassembler::Fail;
2479   }
2480 
2481   return S;
2482 }
2483 
2484 static DecodeStatus DecodeVLD2DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2485                                     uint64_t Address, const void *Decoder) {
2486   DecodeStatus S = MCDisassembler::Success;
2487 
2488   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2489   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2490   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2491   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2492   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2493   unsigned size = 1 << fieldFromInstruction32(Insn, 6, 2);
2494   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2495   align *= 2*size;
2496 
2497   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2498     return MCDisassembler::Fail;
2499   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
2500     return MCDisassembler::Fail;
2501   if (Rm != 0xF) {
2502     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2503       return MCDisassembler::Fail;
2504   }
2505 
2506   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2507     return MCDisassembler::Fail;
2508   Inst.addOperand(MCOperand::CreateImm(align));
2509 
2510   if (Rm == 0xD)
2511     Inst.addOperand(MCOperand::CreateReg(0));
2512   else if (Rm != 0xF) {
2513     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2514       return MCDisassembler::Fail;
2515   }
2516 
2517   return S;
2518 }
2519 
2520 static DecodeStatus DecodeVLD3DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2521                                     uint64_t Address, const void *Decoder) {
2522   DecodeStatus S = MCDisassembler::Success;
2523 
2524   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2525   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2526   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2527   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2528   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2529 
2530   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2531     return MCDisassembler::Fail;
2532   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
2533     return MCDisassembler::Fail;
2534   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
2535     return MCDisassembler::Fail;
2536   if (Rm != 0xF) {
2537     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2538       return MCDisassembler::Fail;
2539   }
2540 
2541   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2542     return MCDisassembler::Fail;
2543   Inst.addOperand(MCOperand::CreateImm(0));
2544 
2545   if (Rm == 0xD)
2546     Inst.addOperand(MCOperand::CreateReg(0));
2547   else if (Rm != 0xF) {
2548     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2549       return MCDisassembler::Fail;
2550   }
2551 
2552   return S;
2553 }
2554 
2555 static DecodeStatus DecodeVLD4DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2556                                     uint64_t Address, const void *Decoder) {
2557   DecodeStatus S = MCDisassembler::Success;
2558 
2559   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2560   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2561   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2562   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2563   unsigned size = fieldFromInstruction32(Insn, 6, 2);
2564   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2565   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2566 
2567   if (size == 0x3) {
2568     size = 4;
2569     align = 16;
2570   } else {
2571     if (size == 2) {
2572       size = 1 << size;
2573       align *= 8;
2574     } else {
2575       size = 1 << size;
2576       align *= 4*size;
2577     }
2578   }
2579 
2580   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2581     return MCDisassembler::Fail;
2582   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
2583     return MCDisassembler::Fail;
2584   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
2585     return MCDisassembler::Fail;
2586   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3*inc)%32, Address, Decoder)))
2587     return MCDisassembler::Fail;
2588   if (Rm != 0xF) {
2589     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2590       return MCDisassembler::Fail;
2591   }
2592 
2593   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2594     return MCDisassembler::Fail;
2595   Inst.addOperand(MCOperand::CreateImm(align));
2596 
2597   if (Rm == 0xD)
2598     Inst.addOperand(MCOperand::CreateReg(0));
2599   else if (Rm != 0xF) {
2600     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2601       return MCDisassembler::Fail;
2602   }
2603 
2604   return S;
2605 }
2606 
2607 static DecodeStatus
2608 DecodeNEONModImmInstruction(llvm::MCInst &Inst, unsigned Insn,
2609                             uint64_t Address, const void *Decoder) {
2610   DecodeStatus S = MCDisassembler::Success;
2611 
2612   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2613   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2614   unsigned imm = fieldFromInstruction32(Insn, 0, 4);
2615   imm |= fieldFromInstruction32(Insn, 16, 3) << 4;
2616   imm |= fieldFromInstruction32(Insn, 24, 1) << 7;
2617   imm |= fieldFromInstruction32(Insn, 8, 4) << 8;
2618   imm |= fieldFromInstruction32(Insn, 5, 1) << 12;
2619   unsigned Q = fieldFromInstruction32(Insn, 6, 1);
2620 
2621   if (Q) {
2622     if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2623     return MCDisassembler::Fail;
2624   } else {
2625     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2626     return MCDisassembler::Fail;
2627   }
2628 
2629   Inst.addOperand(MCOperand::CreateImm(imm));
2630 
2631   switch (Inst.getOpcode()) {
2632     case ARM::VORRiv4i16:
2633     case ARM::VORRiv2i32:
2634     case ARM::VBICiv4i16:
2635     case ARM::VBICiv2i32:
2636       if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2637         return MCDisassembler::Fail;
2638       break;
2639     case ARM::VORRiv8i16:
2640     case ARM::VORRiv4i32:
2641     case ARM::VBICiv8i16:
2642     case ARM::VBICiv4i32:
2643       if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2644         return MCDisassembler::Fail;
2645       break;
2646     default:
2647       break;
2648   }
2649 
2650   return S;
2651 }
2652 
2653 static DecodeStatus DecodeVSHLMaxInstruction(llvm::MCInst &Inst, unsigned Insn,
2654                                         uint64_t Address, const void *Decoder) {
2655   DecodeStatus S = MCDisassembler::Success;
2656 
2657   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2658   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2659   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2660   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
2661   unsigned size = fieldFromInstruction32(Insn, 18, 2);
2662 
2663   if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2664     return MCDisassembler::Fail;
2665   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
2666     return MCDisassembler::Fail;
2667   Inst.addOperand(MCOperand::CreateImm(8 << size));
2668 
2669   return S;
2670 }
2671 
2672 static DecodeStatus DecodeShiftRight8Imm(llvm::MCInst &Inst, unsigned Val,
2673                                uint64_t Address, const void *Decoder) {
2674   Inst.addOperand(MCOperand::CreateImm(8 - Val));
2675   return MCDisassembler::Success;
2676 }
2677 
2678 static DecodeStatus DecodeShiftRight16Imm(llvm::MCInst &Inst, unsigned Val,
2679                                uint64_t Address, const void *Decoder) {
2680   Inst.addOperand(MCOperand::CreateImm(16 - Val));
2681   return MCDisassembler::Success;
2682 }
2683 
2684 static DecodeStatus DecodeShiftRight32Imm(llvm::MCInst &Inst, unsigned Val,
2685                                uint64_t Address, const void *Decoder) {
2686   Inst.addOperand(MCOperand::CreateImm(32 - Val));
2687   return MCDisassembler::Success;
2688 }
2689 
2690 static DecodeStatus DecodeShiftRight64Imm(llvm::MCInst &Inst, unsigned Val,
2691                                uint64_t Address, const void *Decoder) {
2692   Inst.addOperand(MCOperand::CreateImm(64 - Val));
2693   return MCDisassembler::Success;
2694 }
2695 
2696 static DecodeStatus DecodeTBLInstruction(llvm::MCInst &Inst, unsigned Insn,
2697                                uint64_t Address, const void *Decoder) {
2698   DecodeStatus S = MCDisassembler::Success;
2699 
2700   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2701   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2702   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2703   Rn |= fieldFromInstruction32(Insn, 7, 1) << 4;
2704   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2705   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
2706   unsigned op = fieldFromInstruction32(Insn, 6, 1);
2707   unsigned length = fieldFromInstruction32(Insn, 8, 2) + 1;
2708 
2709   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2710     return MCDisassembler::Fail;
2711   if (op) {
2712     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2713     return MCDisassembler::Fail; // Writeback
2714   }
2715 
2716   for (unsigned i = 0; i < length; ++i) {
2717     if (!Check(S, DecodeDPRRegisterClass(Inst, (Rn+i)%32, Address, Decoder)))
2718     return MCDisassembler::Fail;
2719   }
2720 
2721   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
2722     return MCDisassembler::Fail;
2723 
2724   return S;
2725 }
2726 
2727 static DecodeStatus DecodeThumbAddSpecialReg(llvm::MCInst &Inst, uint16_t Insn,
2728                                      uint64_t Address, const void *Decoder) {
2729   DecodeStatus S = MCDisassembler::Success;
2730 
2731   unsigned dst = fieldFromInstruction16(Insn, 8, 3);
2732   unsigned imm = fieldFromInstruction16(Insn, 0, 8);
2733 
2734   if (!Check(S, DecodetGPRRegisterClass(Inst, dst, Address, Decoder)))
2735     return MCDisassembler::Fail;
2736 
2737   switch(Inst.getOpcode()) {
2738     default:
2739       return MCDisassembler::Fail;
2740     case ARM::tADR:
2741       break; // tADR does not explicitly represent the PC as an operand.
2742     case ARM::tADDrSPi:
2743       Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2744       break;
2745   }
2746 
2747   Inst.addOperand(MCOperand::CreateImm(imm));
2748   return S;
2749 }
2750 
2751 static DecodeStatus DecodeThumbBROperand(llvm::MCInst &Inst, unsigned Val,
2752                                  uint64_t Address, const void *Decoder) {
2753   Inst.addOperand(MCOperand::CreateImm(SignExtend32<12>(Val << 1)));
2754   return MCDisassembler::Success;
2755 }
2756 
2757 static DecodeStatus DecodeT2BROperand(llvm::MCInst &Inst, unsigned Val,
2758                                  uint64_t Address, const void *Decoder) {
2759   Inst.addOperand(MCOperand::CreateImm(SignExtend32<21>(Val)));
2760   return MCDisassembler::Success;
2761 }
2762 
2763 static DecodeStatus DecodeThumbCmpBROperand(llvm::MCInst &Inst, unsigned Val,
2764                                  uint64_t Address, const void *Decoder) {
2765   Inst.addOperand(MCOperand::CreateImm(SignExtend32<7>(Val << 1)));
2766   return MCDisassembler::Success;
2767 }
2768 
2769 static DecodeStatus DecodeThumbAddrModeRR(llvm::MCInst &Inst, unsigned Val,
2770                                  uint64_t Address, const void *Decoder) {
2771   DecodeStatus S = MCDisassembler::Success;
2772 
2773   unsigned Rn = fieldFromInstruction32(Val, 0, 3);
2774   unsigned Rm = fieldFromInstruction32(Val, 3, 3);
2775 
2776   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
2777     return MCDisassembler::Fail;
2778   if (!Check(S, DecodetGPRRegisterClass(Inst, Rm, Address, Decoder)))
2779     return MCDisassembler::Fail;
2780 
2781   return S;
2782 }
2783 
2784 static DecodeStatus DecodeThumbAddrModeIS(llvm::MCInst &Inst, unsigned Val,
2785                                   uint64_t Address, const void *Decoder) {
2786   DecodeStatus S = MCDisassembler::Success;
2787 
2788   unsigned Rn = fieldFromInstruction32(Val, 0, 3);
2789   unsigned imm = fieldFromInstruction32(Val, 3, 5);
2790 
2791   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
2792     return MCDisassembler::Fail;
2793   Inst.addOperand(MCOperand::CreateImm(imm));
2794 
2795   return S;
2796 }
2797 
2798 static DecodeStatus DecodeThumbAddrModePC(llvm::MCInst &Inst, unsigned Val,
2799                                   uint64_t Address, const void *Decoder) {
2800   unsigned imm = Val << 2;
2801 
2802   Inst.addOperand(MCOperand::CreateImm(imm));
2803   tryAddingPcLoadReferenceComment(Address, (Address & ~2u) + imm + 4, Decoder);
2804 
2805   return MCDisassembler::Success;
2806 }
2807 
2808 static DecodeStatus DecodeThumbAddrModeSP(llvm::MCInst &Inst, unsigned Val,
2809                                   uint64_t Address, const void *Decoder) {
2810   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2811   Inst.addOperand(MCOperand::CreateImm(Val));
2812 
2813   return MCDisassembler::Success;
2814 }
2815 
2816 static DecodeStatus DecodeT2AddrModeSOReg(llvm::MCInst &Inst, unsigned Val,
2817                                   uint64_t Address, const void *Decoder) {
2818   DecodeStatus S = MCDisassembler::Success;
2819 
2820   unsigned Rn = fieldFromInstruction32(Val, 6, 4);
2821   unsigned Rm = fieldFromInstruction32(Val, 2, 4);
2822   unsigned imm = fieldFromInstruction32(Val, 0, 2);
2823 
2824   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2825     return MCDisassembler::Fail;
2826   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
2827     return MCDisassembler::Fail;
2828   Inst.addOperand(MCOperand::CreateImm(imm));
2829 
2830   return S;
2831 }
2832 
2833 static DecodeStatus DecodeT2LoadShift(llvm::MCInst &Inst, unsigned Insn,
2834                               uint64_t Address, const void *Decoder) {
2835   DecodeStatus S = MCDisassembler::Success;
2836 
2837   switch (Inst.getOpcode()) {
2838     case ARM::t2PLDs:
2839     case ARM::t2PLDWs:
2840     case ARM::t2PLIs:
2841       break;
2842     default: {
2843       unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2844       if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
2845     return MCDisassembler::Fail;
2846     }
2847   }
2848 
2849   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2850   if (Rn == 0xF) {
2851     switch (Inst.getOpcode()) {
2852       case ARM::t2LDRBs:
2853         Inst.setOpcode(ARM::t2LDRBpci);
2854         break;
2855       case ARM::t2LDRHs:
2856         Inst.setOpcode(ARM::t2LDRHpci);
2857         break;
2858       case ARM::t2LDRSHs:
2859         Inst.setOpcode(ARM::t2LDRSHpci);
2860         break;
2861       case ARM::t2LDRSBs:
2862         Inst.setOpcode(ARM::t2LDRSBpci);
2863         break;
2864       case ARM::t2PLDs:
2865         Inst.setOpcode(ARM::t2PLDi12);
2866         Inst.addOperand(MCOperand::CreateReg(ARM::PC));
2867         break;
2868       default:
2869         return MCDisassembler::Fail;
2870     }
2871 
2872     int imm = fieldFromInstruction32(Insn, 0, 12);
2873     if (!fieldFromInstruction32(Insn, 23, 1)) imm *= -1;
2874     Inst.addOperand(MCOperand::CreateImm(imm));
2875 
2876     return S;
2877   }
2878 
2879   unsigned addrmode = fieldFromInstruction32(Insn, 4, 2);
2880   addrmode |= fieldFromInstruction32(Insn, 0, 4) << 2;
2881   addrmode |= fieldFromInstruction32(Insn, 16, 4) << 6;
2882   if (!Check(S, DecodeT2AddrModeSOReg(Inst, addrmode, Address, Decoder)))
2883     return MCDisassembler::Fail;
2884 
2885   return S;
2886 }
2887 
2888 static DecodeStatus DecodeT2Imm8S4(llvm::MCInst &Inst, unsigned Val,
2889                            uint64_t Address, const void *Decoder) {
2890   int imm = Val & 0xFF;
2891   if (!(Val & 0x100)) imm *= -1;
2892   Inst.addOperand(MCOperand::CreateImm(imm << 2));
2893 
2894   return MCDisassembler::Success;
2895 }
2896 
2897 static DecodeStatus DecodeT2AddrModeImm8s4(llvm::MCInst &Inst, unsigned Val,
2898                                    uint64_t Address, const void *Decoder) {
2899   DecodeStatus S = MCDisassembler::Success;
2900 
2901   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
2902   unsigned imm = fieldFromInstruction32(Val, 0, 9);
2903 
2904   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2905     return MCDisassembler::Fail;
2906   if (!Check(S, DecodeT2Imm8S4(Inst, imm, Address, Decoder)))
2907     return MCDisassembler::Fail;
2908 
2909   return S;
2910 }
2911 
2912 static DecodeStatus DecodeT2AddrModeImm0_1020s4(llvm::MCInst &Inst,unsigned Val,
2913                                    uint64_t Address, const void *Decoder) {
2914   DecodeStatus S = MCDisassembler::Success;
2915 
2916   unsigned Rn = fieldFromInstruction32(Val, 8, 4);
2917   unsigned imm = fieldFromInstruction32(Val, 0, 8);
2918 
2919   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
2920     return MCDisassembler::Fail;
2921 
2922   Inst.addOperand(MCOperand::CreateImm(imm));
2923 
2924   return S;
2925 }
2926 
2927 static DecodeStatus DecodeT2Imm8(llvm::MCInst &Inst, unsigned Val,
2928                          uint64_t Address, const void *Decoder) {
2929   int imm = Val & 0xFF;
2930   if (Val == 0)
2931     imm = INT32_MIN;
2932   else if (!(Val & 0x100))
2933     imm *= -1;
2934   Inst.addOperand(MCOperand::CreateImm(imm));
2935 
2936   return MCDisassembler::Success;
2937 }
2938 
2939 
2940 static DecodeStatus DecodeT2AddrModeImm8(llvm::MCInst &Inst, unsigned Val,
2941                                  uint64_t Address, const void *Decoder) {
2942   DecodeStatus S = MCDisassembler::Success;
2943 
2944   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
2945   unsigned imm = fieldFromInstruction32(Val, 0, 9);
2946 
2947   // Some instructions always use an additive offset.
2948   switch (Inst.getOpcode()) {
2949     case ARM::t2LDRT:
2950     case ARM::t2LDRBT:
2951     case ARM::t2LDRHT:
2952     case ARM::t2LDRSBT:
2953     case ARM::t2LDRSHT:
2954     case ARM::t2STRT:
2955     case ARM::t2STRBT:
2956     case ARM::t2STRHT:
2957       imm |= 0x100;
2958       break;
2959     default:
2960       break;
2961   }
2962 
2963   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2964     return MCDisassembler::Fail;
2965   if (!Check(S, DecodeT2Imm8(Inst, imm, Address, Decoder)))
2966     return MCDisassembler::Fail;
2967 
2968   return S;
2969 }
2970 
2971 static DecodeStatus DecodeT2LdStPre(llvm::MCInst &Inst, unsigned Insn,
2972                                     uint64_t Address, const void *Decoder) {
2973   DecodeStatus S = MCDisassembler::Success;
2974 
2975   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2976   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2977   unsigned addr = fieldFromInstruction32(Insn, 0, 8);
2978   addr |= fieldFromInstruction32(Insn, 9, 1) << 8;
2979   addr |= Rn << 9;
2980   unsigned load = fieldFromInstruction32(Insn, 20, 1);
2981 
2982   if (!load) {
2983     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2984       return MCDisassembler::Fail;
2985   }
2986 
2987   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
2988     return MCDisassembler::Fail;
2989 
2990   if (load) {
2991     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2992       return MCDisassembler::Fail;
2993   }
2994 
2995   if (!Check(S, DecodeT2AddrModeImm8(Inst, addr, Address, Decoder)))
2996     return MCDisassembler::Fail;
2997 
2998   return S;
2999 }
3000 
3001 static DecodeStatus DecodeT2AddrModeImm12(llvm::MCInst &Inst, unsigned Val,
3002                                   uint64_t Address, const void *Decoder) {
3003   DecodeStatus S = MCDisassembler::Success;
3004 
3005   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
3006   unsigned imm = fieldFromInstruction32(Val, 0, 12);
3007 
3008   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3009     return MCDisassembler::Fail;
3010   Inst.addOperand(MCOperand::CreateImm(imm));
3011 
3012   return S;
3013 }
3014 
3015 
3016 static DecodeStatus DecodeThumbAddSPImm(llvm::MCInst &Inst, uint16_t Insn,
3017                                 uint64_t Address, const void *Decoder) {
3018   unsigned imm = fieldFromInstruction16(Insn, 0, 7);
3019 
3020   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
3021   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
3022   Inst.addOperand(MCOperand::CreateImm(imm));
3023 
3024   return MCDisassembler::Success;
3025 }
3026 
3027 static DecodeStatus DecodeThumbAddSPReg(llvm::MCInst &Inst, uint16_t Insn,
3028                                 uint64_t Address, const void *Decoder) {
3029   DecodeStatus S = MCDisassembler::Success;
3030 
3031   if (Inst.getOpcode() == ARM::tADDrSP) {
3032     unsigned Rdm = fieldFromInstruction16(Insn, 0, 3);
3033     Rdm |= fieldFromInstruction16(Insn, 7, 1) << 3;
3034 
3035     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
3036     return MCDisassembler::Fail;
3037     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
3038     return MCDisassembler::Fail;
3039     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
3040   } else if (Inst.getOpcode() == ARM::tADDspr) {
3041     unsigned Rm = fieldFromInstruction16(Insn, 3, 4);
3042 
3043     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
3044     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
3045     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3046     return MCDisassembler::Fail;
3047   }
3048 
3049   return S;
3050 }
3051 
3052 static DecodeStatus DecodeThumbCPS(llvm::MCInst &Inst, uint16_t Insn,
3053                            uint64_t Address, const void *Decoder) {
3054   unsigned imod = fieldFromInstruction16(Insn, 4, 1) | 0x2;
3055   unsigned flags = fieldFromInstruction16(Insn, 0, 3);
3056 
3057   Inst.addOperand(MCOperand::CreateImm(imod));
3058   Inst.addOperand(MCOperand::CreateImm(flags));
3059 
3060   return MCDisassembler::Success;
3061 }
3062 
3063 static DecodeStatus DecodePostIdxReg(llvm::MCInst &Inst, unsigned Insn,
3064                              uint64_t Address, const void *Decoder) {
3065   DecodeStatus S = MCDisassembler::Success;
3066   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3067   unsigned add = fieldFromInstruction32(Insn, 4, 1);
3068 
3069   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3070     return MCDisassembler::Fail;
3071   Inst.addOperand(MCOperand::CreateImm(add));
3072 
3073   return S;
3074 }
3075 
3076 static DecodeStatus DecodeThumbBLXOffset(llvm::MCInst &Inst, unsigned Val,
3077                                  uint64_t Address, const void *Decoder) {
3078   if (!tryAddingSymbolicOperand(Address,
3079                                 (Address & ~2u) + SignExtend32<22>(Val << 1) + 4,
3080                                 true, 4, Inst, Decoder))
3081     Inst.addOperand(MCOperand::CreateImm(SignExtend32<22>(Val << 1)));
3082   return MCDisassembler::Success;
3083 }
3084 
3085 static DecodeStatus DecodeCoprocessor(llvm::MCInst &Inst, unsigned Val,
3086                               uint64_t Address, const void *Decoder) {
3087   if (Val == 0xA || Val == 0xB)
3088     return MCDisassembler::Fail;
3089 
3090   Inst.addOperand(MCOperand::CreateImm(Val));
3091   return MCDisassembler::Success;
3092 }
3093 
3094 static DecodeStatus
3095 DecodeThumbTableBranch(llvm::MCInst &Inst, unsigned Insn,
3096                        uint64_t Address, const void *Decoder) {
3097   DecodeStatus S = MCDisassembler::Success;
3098 
3099   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3100   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3101 
3102   if (Rn == ARM::SP) S = MCDisassembler::SoftFail;
3103   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3104     return MCDisassembler::Fail;
3105   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
3106     return MCDisassembler::Fail;
3107   return S;
3108 }
3109 
3110 static DecodeStatus
3111 DecodeThumb2BCCInstruction(llvm::MCInst &Inst, unsigned Insn,
3112                            uint64_t Address, const void *Decoder) {
3113   DecodeStatus S = MCDisassembler::Success;
3114 
3115   unsigned pred = fieldFromInstruction32(Insn, 22, 4);
3116   if (pred == 0xE || pred == 0xF) {
3117     unsigned opc = fieldFromInstruction32(Insn, 4, 28);
3118     switch (opc) {
3119       default:
3120         return MCDisassembler::Fail;
3121       case 0xf3bf8f4:
3122         Inst.setOpcode(ARM::t2DSB);
3123         break;
3124       case 0xf3bf8f5:
3125         Inst.setOpcode(ARM::t2DMB);
3126         break;
3127       case 0xf3bf8f6:
3128         Inst.setOpcode(ARM::t2ISB);
3129         break;
3130     }
3131 
3132     unsigned imm = fieldFromInstruction32(Insn, 0, 4);
3133     return DecodeMemBarrierOption(Inst, imm, Address, Decoder);
3134   }
3135 
3136   unsigned brtarget = fieldFromInstruction32(Insn, 0, 11) << 1;
3137   brtarget |= fieldFromInstruction32(Insn, 11, 1) << 19;
3138   brtarget |= fieldFromInstruction32(Insn, 13, 1) << 18;
3139   brtarget |= fieldFromInstruction32(Insn, 16, 6) << 12;
3140   brtarget |= fieldFromInstruction32(Insn, 26, 1) << 20;
3141 
3142   if (!Check(S, DecodeT2BROperand(Inst, brtarget, Address, Decoder)))
3143     return MCDisassembler::Fail;
3144   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3145     return MCDisassembler::Fail;
3146 
3147   return S;
3148 }
3149 
3150 // Decode a shifted immediate operand.  These basically consist
3151 // of an 8-bit value, and a 4-bit directive that specifies either
3152 // a splat operation or a rotation.
3153 static DecodeStatus DecodeT2SOImm(llvm::MCInst &Inst, unsigned Val,
3154                           uint64_t Address, const void *Decoder) {
3155   unsigned ctrl = fieldFromInstruction32(Val, 10, 2);
3156   if (ctrl == 0) {
3157     unsigned byte = fieldFromInstruction32(Val, 8, 2);
3158     unsigned imm = fieldFromInstruction32(Val, 0, 8);
3159     switch (byte) {
3160       case 0:
3161         Inst.addOperand(MCOperand::CreateImm(imm));
3162         break;
3163       case 1:
3164         Inst.addOperand(MCOperand::CreateImm((imm << 16) | imm));
3165         break;
3166       case 2:
3167         Inst.addOperand(MCOperand::CreateImm((imm << 24) | (imm << 8)));
3168         break;
3169       case 3:
3170         Inst.addOperand(MCOperand::CreateImm((imm << 24) | (imm << 16) |
3171                                              (imm << 8)  |  imm));
3172         break;
3173     }
3174   } else {
3175     unsigned unrot = fieldFromInstruction32(Val, 0, 7) | 0x80;
3176     unsigned rot = fieldFromInstruction32(Val, 7, 5);
3177     unsigned imm = (unrot >> rot) | (unrot << ((32-rot)&31));
3178     Inst.addOperand(MCOperand::CreateImm(imm));
3179   }
3180 
3181   return MCDisassembler::Success;
3182 }
3183 
3184 static DecodeStatus
3185 DecodeThumbBCCTargetOperand(llvm::MCInst &Inst, unsigned Val,
3186                             uint64_t Address, const void *Decoder){
3187   Inst.addOperand(MCOperand::CreateImm(Val << 1));
3188   return MCDisassembler::Success;
3189 }
3190 
3191 static DecodeStatus DecodeThumbBLTargetOperand(llvm::MCInst &Inst, unsigned Val,
3192                                        uint64_t Address, const void *Decoder){
3193   Inst.addOperand(MCOperand::CreateImm(SignExtend32<22>(Val << 1)));
3194   return MCDisassembler::Success;
3195 }
3196 
3197 static DecodeStatus DecodeMemBarrierOption(llvm::MCInst &Inst, unsigned Val,
3198                                    uint64_t Address, const void *Decoder) {
3199   switch (Val) {
3200   default:
3201     return MCDisassembler::Fail;
3202   case 0xF: // SY
3203   case 0xE: // ST
3204   case 0xB: // ISH
3205   case 0xA: // ISHST
3206   case 0x7: // NSH
3207   case 0x6: // NSHST
3208   case 0x3: // OSH
3209   case 0x2: // OSHST
3210     break;
3211   }
3212 
3213   Inst.addOperand(MCOperand::CreateImm(Val));
3214   return MCDisassembler::Success;
3215 }
3216 
3217 static DecodeStatus DecodeMSRMask(llvm::MCInst &Inst, unsigned Val,
3218                           uint64_t Address, const void *Decoder) {
3219   if (!Val) return MCDisassembler::Fail;
3220   Inst.addOperand(MCOperand::CreateImm(Val));
3221   return MCDisassembler::Success;
3222 }
3223 
3224 static DecodeStatus DecodeDoubleRegLoad(llvm::MCInst &Inst, unsigned Insn,
3225                                         uint64_t Address, const void *Decoder) {
3226   DecodeStatus S = MCDisassembler::Success;
3227 
3228   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3229   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3230   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3231 
3232   if ((Rt & 1) || Rt == 0xE || Rn == 0xF) return MCDisassembler::Fail;
3233 
3234   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3235     return MCDisassembler::Fail;
3236   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
3237     return MCDisassembler::Fail;
3238   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3239     return MCDisassembler::Fail;
3240   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3241     return MCDisassembler::Fail;
3242 
3243   return S;
3244 }
3245 
3246 
3247 static DecodeStatus DecodeDoubleRegStore(llvm::MCInst &Inst, unsigned Insn,
3248                                          uint64_t Address, const void *Decoder){
3249   DecodeStatus S = MCDisassembler::Success;
3250 
3251   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3252   unsigned Rt = fieldFromInstruction32(Insn, 0, 4);
3253   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3254   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3255 
3256   if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
3257     return MCDisassembler::Fail;
3258 
3259   if ((Rt & 1) || Rt == 0xE || Rn == 0xF) return MCDisassembler::Fail;
3260   if (Rd == Rn || Rd == Rt || Rd == Rt+1) return MCDisassembler::Fail;
3261 
3262   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3263     return MCDisassembler::Fail;
3264   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
3265     return MCDisassembler::Fail;
3266   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3267     return MCDisassembler::Fail;
3268   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3269     return MCDisassembler::Fail;
3270 
3271   return S;
3272 }
3273 
3274 static DecodeStatus DecodeLDRPreImm(llvm::MCInst &Inst, unsigned Insn,
3275                             uint64_t Address, const void *Decoder) {
3276   DecodeStatus S = MCDisassembler::Success;
3277 
3278   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3279   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3280   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3281   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3282   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3283   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3284 
3285   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3286 
3287   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3288     return MCDisassembler::Fail;
3289   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3290     return MCDisassembler::Fail;
3291   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
3292     return MCDisassembler::Fail;
3293   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3294     return MCDisassembler::Fail;
3295 
3296   return S;
3297 }
3298 
3299 static DecodeStatus DecodeLDRPreReg(llvm::MCInst &Inst, unsigned Insn,
3300                             uint64_t Address, const void *Decoder) {
3301   DecodeStatus S = MCDisassembler::Success;
3302 
3303   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3304   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3305   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3306   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3307   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3308   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3309   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3310 
3311   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3312   if (Rm == 0xF) S = MCDisassembler::SoftFail;
3313 
3314   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3315     return MCDisassembler::Fail;
3316   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3317     return MCDisassembler::Fail;
3318   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
3319     return MCDisassembler::Fail;
3320   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3321     return MCDisassembler::Fail;
3322 
3323   return S;
3324 }
3325 
3326 
3327 static DecodeStatus DecodeSTRPreImm(llvm::MCInst &Inst, unsigned Insn,
3328                             uint64_t Address, const void *Decoder) {
3329   DecodeStatus S = MCDisassembler::Success;
3330 
3331   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3332   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3333   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3334   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3335   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3336   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3337 
3338   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3339 
3340   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3341     return MCDisassembler::Fail;
3342   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3343     return MCDisassembler::Fail;
3344   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
3345     return MCDisassembler::Fail;
3346   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3347     return MCDisassembler::Fail;
3348 
3349   return S;
3350 }
3351 
3352 static DecodeStatus DecodeSTRPreReg(llvm::MCInst &Inst, unsigned Insn,
3353                             uint64_t Address, const void *Decoder) {
3354   DecodeStatus S = MCDisassembler::Success;
3355 
3356   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3357   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3358   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3359   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3360   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3361   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3362 
3363   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3364 
3365   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3366     return MCDisassembler::Fail;
3367   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3368     return MCDisassembler::Fail;
3369   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
3370     return MCDisassembler::Fail;
3371   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3372     return MCDisassembler::Fail;
3373 
3374   return S;
3375 }
3376 
3377 static DecodeStatus DecodeVLD1LN(llvm::MCInst &Inst, unsigned Insn,
3378                          uint64_t Address, const void *Decoder) {
3379   DecodeStatus S = MCDisassembler::Success;
3380 
3381   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3382   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3383   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3384   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3385   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3386 
3387   unsigned align = 0;
3388   unsigned index = 0;
3389   switch (size) {
3390     default:
3391       return MCDisassembler::Fail;
3392     case 0:
3393       if (fieldFromInstruction32(Insn, 4, 1))
3394         return MCDisassembler::Fail; // UNDEFINED
3395       index = fieldFromInstruction32(Insn, 5, 3);
3396       break;
3397     case 1:
3398       if (fieldFromInstruction32(Insn, 5, 1))
3399         return MCDisassembler::Fail; // UNDEFINED
3400       index = fieldFromInstruction32(Insn, 6, 2);
3401       if (fieldFromInstruction32(Insn, 4, 1))
3402         align = 2;
3403       break;
3404     case 2:
3405       if (fieldFromInstruction32(Insn, 6, 1))
3406         return MCDisassembler::Fail; // UNDEFINED
3407       index = fieldFromInstruction32(Insn, 7, 1);
3408       if (fieldFromInstruction32(Insn, 4, 2) != 0)
3409         align = 4;
3410   }
3411 
3412   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3413     return MCDisassembler::Fail;
3414   if (Rm != 0xF) { // Writeback
3415     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3416       return MCDisassembler::Fail;
3417   }
3418   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3419     return MCDisassembler::Fail;
3420   Inst.addOperand(MCOperand::CreateImm(align));
3421   if (Rm != 0xF) {
3422     if (Rm != 0xD) {
3423       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3424         return MCDisassembler::Fail;
3425     } else
3426       Inst.addOperand(MCOperand::CreateReg(0));
3427   }
3428 
3429   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3430     return MCDisassembler::Fail;
3431   Inst.addOperand(MCOperand::CreateImm(index));
3432 
3433   return S;
3434 }
3435 
3436 static DecodeStatus DecodeVST1LN(llvm::MCInst &Inst, unsigned Insn,
3437                          uint64_t Address, const void *Decoder) {
3438   DecodeStatus S = MCDisassembler::Success;
3439 
3440   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3441   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3442   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3443   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3444   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3445 
3446   unsigned align = 0;
3447   unsigned index = 0;
3448   switch (size) {
3449     default:
3450       return MCDisassembler::Fail;
3451     case 0:
3452       if (fieldFromInstruction32(Insn, 4, 1))
3453         return MCDisassembler::Fail; // UNDEFINED
3454       index = fieldFromInstruction32(Insn, 5, 3);
3455       break;
3456     case 1:
3457       if (fieldFromInstruction32(Insn, 5, 1))
3458         return MCDisassembler::Fail; // UNDEFINED
3459       index = fieldFromInstruction32(Insn, 6, 2);
3460       if (fieldFromInstruction32(Insn, 4, 1))
3461         align = 2;
3462       break;
3463     case 2:
3464       if (fieldFromInstruction32(Insn, 6, 1))
3465         return MCDisassembler::Fail; // UNDEFINED
3466       index = fieldFromInstruction32(Insn, 7, 1);
3467       if (fieldFromInstruction32(Insn, 4, 2) != 0)
3468         align = 4;
3469   }
3470 
3471   if (Rm != 0xF) { // Writeback
3472     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3473     return MCDisassembler::Fail;
3474   }
3475   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3476     return MCDisassembler::Fail;
3477   Inst.addOperand(MCOperand::CreateImm(align));
3478   if (Rm != 0xF) {
3479     if (Rm != 0xD) {
3480       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3481     return MCDisassembler::Fail;
3482     } else
3483       Inst.addOperand(MCOperand::CreateReg(0));
3484   }
3485 
3486   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3487     return MCDisassembler::Fail;
3488   Inst.addOperand(MCOperand::CreateImm(index));
3489 
3490   return S;
3491 }
3492 
3493 
3494 static DecodeStatus DecodeVLD2LN(llvm::MCInst &Inst, unsigned Insn,
3495                          uint64_t Address, const void *Decoder) {
3496   DecodeStatus S = MCDisassembler::Success;
3497 
3498   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3499   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3500   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3501   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3502   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3503 
3504   unsigned align = 0;
3505   unsigned index = 0;
3506   unsigned inc = 1;
3507   switch (size) {
3508     default:
3509       return MCDisassembler::Fail;
3510     case 0:
3511       index = fieldFromInstruction32(Insn, 5, 3);
3512       if (fieldFromInstruction32(Insn, 4, 1))
3513         align = 2;
3514       break;
3515     case 1:
3516       index = fieldFromInstruction32(Insn, 6, 2);
3517       if (fieldFromInstruction32(Insn, 4, 1))
3518         align = 4;
3519       if (fieldFromInstruction32(Insn, 5, 1))
3520         inc = 2;
3521       break;
3522     case 2:
3523       if (fieldFromInstruction32(Insn, 5, 1))
3524         return MCDisassembler::Fail; // UNDEFINED
3525       index = fieldFromInstruction32(Insn, 7, 1);
3526       if (fieldFromInstruction32(Insn, 4, 1) != 0)
3527         align = 8;
3528       if (fieldFromInstruction32(Insn, 6, 1))
3529         inc = 2;
3530       break;
3531   }
3532 
3533   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3534     return MCDisassembler::Fail;
3535   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3536     return MCDisassembler::Fail;
3537   if (Rm != 0xF) { // Writeback
3538     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3539       return MCDisassembler::Fail;
3540   }
3541   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3542     return MCDisassembler::Fail;
3543   Inst.addOperand(MCOperand::CreateImm(align));
3544   if (Rm != 0xF) {
3545     if (Rm != 0xD) {
3546       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3547         return MCDisassembler::Fail;
3548     } else
3549       Inst.addOperand(MCOperand::CreateReg(0));
3550   }
3551 
3552   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3553     return MCDisassembler::Fail;
3554   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3555     return MCDisassembler::Fail;
3556   Inst.addOperand(MCOperand::CreateImm(index));
3557 
3558   return S;
3559 }
3560 
3561 static DecodeStatus DecodeVST2LN(llvm::MCInst &Inst, unsigned Insn,
3562                          uint64_t Address, const void *Decoder) {
3563   DecodeStatus S = MCDisassembler::Success;
3564 
3565   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3566   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3567   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3568   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3569   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3570 
3571   unsigned align = 0;
3572   unsigned index = 0;
3573   unsigned inc = 1;
3574   switch (size) {
3575     default:
3576       return MCDisassembler::Fail;
3577     case 0:
3578       index = fieldFromInstruction32(Insn, 5, 3);
3579       if (fieldFromInstruction32(Insn, 4, 1))
3580         align = 2;
3581       break;
3582     case 1:
3583       index = fieldFromInstruction32(Insn, 6, 2);
3584       if (fieldFromInstruction32(Insn, 4, 1))
3585         align = 4;
3586       if (fieldFromInstruction32(Insn, 5, 1))
3587         inc = 2;
3588       break;
3589     case 2:
3590       if (fieldFromInstruction32(Insn, 5, 1))
3591         return MCDisassembler::Fail; // UNDEFINED
3592       index = fieldFromInstruction32(Insn, 7, 1);
3593       if (fieldFromInstruction32(Insn, 4, 1) != 0)
3594         align = 8;
3595       if (fieldFromInstruction32(Insn, 6, 1))
3596         inc = 2;
3597       break;
3598   }
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   Inst.addOperand(MCOperand::CreateImm(index));
3620 
3621   return S;
3622 }
3623 
3624 
3625 static DecodeStatus DecodeVLD3LN(llvm::MCInst &Inst, unsigned Insn,
3626                          uint64_t Address, const void *Decoder) {
3627   DecodeStatus S = MCDisassembler::Success;
3628 
3629   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3630   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3631   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3632   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3633   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3634 
3635   unsigned align = 0;
3636   unsigned index = 0;
3637   unsigned inc = 1;
3638   switch (size) {
3639     default:
3640       return MCDisassembler::Fail;
3641     case 0:
3642       if (fieldFromInstruction32(Insn, 4, 1))
3643         return MCDisassembler::Fail; // UNDEFINED
3644       index = fieldFromInstruction32(Insn, 5, 3);
3645       break;
3646     case 1:
3647       if (fieldFromInstruction32(Insn, 4, 1))
3648         return MCDisassembler::Fail; // UNDEFINED
3649       index = fieldFromInstruction32(Insn, 6, 2);
3650       if (fieldFromInstruction32(Insn, 5, 1))
3651         inc = 2;
3652       break;
3653     case 2:
3654       if (fieldFromInstruction32(Insn, 4, 2))
3655         return MCDisassembler::Fail; // UNDEFINED
3656       index = fieldFromInstruction32(Insn, 7, 1);
3657       if (fieldFromInstruction32(Insn, 6, 1))
3658         inc = 2;
3659       break;
3660   }
3661 
3662   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3663     return MCDisassembler::Fail;
3664   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3665     return MCDisassembler::Fail;
3666   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3667     return MCDisassembler::Fail;
3668 
3669   if (Rm != 0xF) { // Writeback
3670     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3671     return MCDisassembler::Fail;
3672   }
3673   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3674     return MCDisassembler::Fail;
3675   Inst.addOperand(MCOperand::CreateImm(align));
3676   if (Rm != 0xF) {
3677     if (Rm != 0xD) {
3678       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3679     return MCDisassembler::Fail;
3680     } else
3681       Inst.addOperand(MCOperand::CreateReg(0));
3682   }
3683 
3684   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3685     return MCDisassembler::Fail;
3686   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3687     return MCDisassembler::Fail;
3688   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3689     return MCDisassembler::Fail;
3690   Inst.addOperand(MCOperand::CreateImm(index));
3691 
3692   return S;
3693 }
3694 
3695 static DecodeStatus DecodeVST3LN(llvm::MCInst &Inst, unsigned Insn,
3696                          uint64_t Address, const void *Decoder) {
3697   DecodeStatus S = MCDisassembler::Success;
3698 
3699   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3700   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3701   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3702   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3703   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3704 
3705   unsigned align = 0;
3706   unsigned index = 0;
3707   unsigned inc = 1;
3708   switch (size) {
3709     default:
3710       return MCDisassembler::Fail;
3711     case 0:
3712       if (fieldFromInstruction32(Insn, 4, 1))
3713         return MCDisassembler::Fail; // UNDEFINED
3714       index = fieldFromInstruction32(Insn, 5, 3);
3715       break;
3716     case 1:
3717       if (fieldFromInstruction32(Insn, 4, 1))
3718         return MCDisassembler::Fail; // UNDEFINED
3719       index = fieldFromInstruction32(Insn, 6, 2);
3720       if (fieldFromInstruction32(Insn, 5, 1))
3721         inc = 2;
3722       break;
3723     case 2:
3724       if (fieldFromInstruction32(Insn, 4, 2))
3725         return MCDisassembler::Fail; // UNDEFINED
3726       index = fieldFromInstruction32(Insn, 7, 1);
3727       if (fieldFromInstruction32(Insn, 6, 1))
3728         inc = 2;
3729       break;
3730   }
3731 
3732   if (Rm != 0xF) { // Writeback
3733     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3734     return MCDisassembler::Fail;
3735   }
3736   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3737     return MCDisassembler::Fail;
3738   Inst.addOperand(MCOperand::CreateImm(align));
3739   if (Rm != 0xF) {
3740     if (Rm != 0xD) {
3741       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3742     return MCDisassembler::Fail;
3743     } else
3744       Inst.addOperand(MCOperand::CreateReg(0));
3745   }
3746 
3747   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3748     return MCDisassembler::Fail;
3749   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3750     return MCDisassembler::Fail;
3751   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3752     return MCDisassembler::Fail;
3753   Inst.addOperand(MCOperand::CreateImm(index));
3754 
3755   return S;
3756 }
3757 
3758 
3759 static DecodeStatus DecodeVLD4LN(llvm::MCInst &Inst, unsigned Insn,
3760                          uint64_t Address, const void *Decoder) {
3761   DecodeStatus S = MCDisassembler::Success;
3762 
3763   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3764   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3765   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3766   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3767   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3768 
3769   unsigned align = 0;
3770   unsigned index = 0;
3771   unsigned inc = 1;
3772   switch (size) {
3773     default:
3774       return MCDisassembler::Fail;
3775     case 0:
3776       if (fieldFromInstruction32(Insn, 4, 1))
3777         align = 4;
3778       index = fieldFromInstruction32(Insn, 5, 3);
3779       break;
3780     case 1:
3781       if (fieldFromInstruction32(Insn, 4, 1))
3782         align = 8;
3783       index = fieldFromInstruction32(Insn, 6, 2);
3784       if (fieldFromInstruction32(Insn, 5, 1))
3785         inc = 2;
3786       break;
3787     case 2:
3788       if (fieldFromInstruction32(Insn, 4, 2))
3789         align = 4 << fieldFromInstruction32(Insn, 4, 2);
3790       index = fieldFromInstruction32(Insn, 7, 1);
3791       if (fieldFromInstruction32(Insn, 6, 1))
3792         inc = 2;
3793       break;
3794   }
3795 
3796   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3797     return MCDisassembler::Fail;
3798   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3799     return MCDisassembler::Fail;
3800   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3801     return MCDisassembler::Fail;
3802   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
3803     return MCDisassembler::Fail;
3804 
3805   if (Rm != 0xF) { // Writeback
3806     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3807       return MCDisassembler::Fail;
3808   }
3809   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3810     return MCDisassembler::Fail;
3811   Inst.addOperand(MCOperand::CreateImm(align));
3812   if (Rm != 0xF) {
3813     if (Rm != 0xD) {
3814       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3815         return MCDisassembler::Fail;
3816     } else
3817       Inst.addOperand(MCOperand::CreateReg(0));
3818   }
3819 
3820   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3821     return MCDisassembler::Fail;
3822   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3823     return MCDisassembler::Fail;
3824   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3825     return MCDisassembler::Fail;
3826   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
3827     return MCDisassembler::Fail;
3828   Inst.addOperand(MCOperand::CreateImm(index));
3829 
3830   return S;
3831 }
3832 
3833 static DecodeStatus DecodeVST4LN(llvm::MCInst &Inst, unsigned Insn,
3834                          uint64_t Address, const void *Decoder) {
3835   DecodeStatus S = MCDisassembler::Success;
3836 
3837   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3838   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3839   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3840   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3841   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3842 
3843   unsigned align = 0;
3844   unsigned index = 0;
3845   unsigned inc = 1;
3846   switch (size) {
3847     default:
3848       return MCDisassembler::Fail;
3849     case 0:
3850       if (fieldFromInstruction32(Insn, 4, 1))
3851         align = 4;
3852       index = fieldFromInstruction32(Insn, 5, 3);
3853       break;
3854     case 1:
3855       if (fieldFromInstruction32(Insn, 4, 1))
3856         align = 8;
3857       index = fieldFromInstruction32(Insn, 6, 2);
3858       if (fieldFromInstruction32(Insn, 5, 1))
3859         inc = 2;
3860       break;
3861     case 2:
3862       if (fieldFromInstruction32(Insn, 4, 2))
3863         align = 4 << fieldFromInstruction32(Insn, 4, 2);
3864       index = fieldFromInstruction32(Insn, 7, 1);
3865       if (fieldFromInstruction32(Insn, 6, 1))
3866         inc = 2;
3867       break;
3868   }
3869 
3870   if (Rm != 0xF) { // Writeback
3871     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3872     return MCDisassembler::Fail;
3873   }
3874   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3875     return MCDisassembler::Fail;
3876   Inst.addOperand(MCOperand::CreateImm(align));
3877   if (Rm != 0xF) {
3878     if (Rm != 0xD) {
3879       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3880     return MCDisassembler::Fail;
3881     } else
3882       Inst.addOperand(MCOperand::CreateReg(0));
3883   }
3884 
3885   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3886     return MCDisassembler::Fail;
3887   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3888     return MCDisassembler::Fail;
3889   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3890     return MCDisassembler::Fail;
3891   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
3892     return MCDisassembler::Fail;
3893   Inst.addOperand(MCOperand::CreateImm(index));
3894 
3895   return S;
3896 }
3897 
3898 static DecodeStatus DecodeVMOVSRR(llvm::MCInst &Inst, unsigned Insn,
3899                                   uint64_t Address, const void *Decoder) {
3900   DecodeStatus S = MCDisassembler::Success;
3901   unsigned Rt  = fieldFromInstruction32(Insn, 12, 4);
3902   unsigned Rt2 = fieldFromInstruction32(Insn, 16, 4);
3903   unsigned Rm  = fieldFromInstruction32(Insn,  0, 4);
3904   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3905   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
3906 
3907   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
3908     S = MCDisassembler::SoftFail;
3909 
3910   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
3911     return MCDisassembler::Fail;
3912   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
3913     return MCDisassembler::Fail;
3914   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
3915     return MCDisassembler::Fail;
3916   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
3917     return MCDisassembler::Fail;
3918   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3919     return MCDisassembler::Fail;
3920 
3921   return S;
3922 }
3923 
3924 static DecodeStatus DecodeVMOVRRS(llvm::MCInst &Inst, unsigned Insn,
3925                                   uint64_t Address, const void *Decoder) {
3926   DecodeStatus S = MCDisassembler::Success;
3927   unsigned Rt  = fieldFromInstruction32(Insn, 12, 4);
3928   unsigned Rt2 = fieldFromInstruction32(Insn, 16, 4);
3929   unsigned Rm  = fieldFromInstruction32(Insn,  0, 4);
3930   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3931   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
3932 
3933   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
3934     S = MCDisassembler::SoftFail;
3935 
3936   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
3937     return MCDisassembler::Fail;
3938   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
3939     return MCDisassembler::Fail;
3940   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
3941     return MCDisassembler::Fail;
3942   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
3943     return MCDisassembler::Fail;
3944   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3945     return MCDisassembler::Fail;
3946 
3947   return S;
3948 }
3949 
3950 static DecodeStatus DecodeIT(llvm::MCInst &Inst, unsigned Insn,
3951                              uint64_t Address, const void *Decoder) {
3952   DecodeStatus S = MCDisassembler::Success;
3953   unsigned pred = fieldFromInstruction16(Insn, 4, 4);
3954   // The InstPrinter needs to have the low bit of the predicate in
3955   // the mask operand to be able to print it properly.
3956   unsigned mask = fieldFromInstruction16(Insn, 0, 5);
3957 
3958   if (pred == 0xF) {
3959     pred = 0xE;
3960     S = MCDisassembler::SoftFail;
3961   }
3962 
3963   if ((mask & 0xF) == 0) {
3964     // Preserve the high bit of the mask, which is the low bit of
3965     // the predicate.
3966     mask &= 0x10;
3967     mask |= 0x8;
3968     S = MCDisassembler::SoftFail;
3969   }
3970 
3971   Inst.addOperand(MCOperand::CreateImm(pred));
3972   Inst.addOperand(MCOperand::CreateImm(mask));
3973   return S;
3974 }
3975 
3976 static DecodeStatus
3977 DecodeT2LDRDPreInstruction(llvm::MCInst &Inst, unsigned Insn,
3978                            uint64_t Address, const void *Decoder) {
3979   DecodeStatus S = MCDisassembler::Success;
3980 
3981   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3982   unsigned Rt2 = fieldFromInstruction32(Insn, 8, 4);
3983   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3984   unsigned addr = fieldFromInstruction32(Insn, 0, 8);
3985   unsigned W = fieldFromInstruction32(Insn, 21, 1);
3986   unsigned U = fieldFromInstruction32(Insn, 23, 1);
3987   unsigned P = fieldFromInstruction32(Insn, 24, 1);
3988   bool writeback = (W == 1) | (P == 0);
3989 
3990   addr |= (U << 8) | (Rn << 9);
3991 
3992   if (writeback && (Rn == Rt || Rn == Rt2))
3993     Check(S, MCDisassembler::SoftFail);
3994   if (Rt == Rt2)
3995     Check(S, MCDisassembler::SoftFail);
3996 
3997   // Rt
3998   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
3999     return MCDisassembler::Fail;
4000   // Rt2
4001   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
4002     return MCDisassembler::Fail;
4003   // Writeback operand
4004   if (!Check(S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
4005     return MCDisassembler::Fail;
4006   // addr
4007   if (!Check(S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
4008     return MCDisassembler::Fail;
4009 
4010   return S;
4011 }
4012 
4013 static DecodeStatus
4014 DecodeT2STRDPreInstruction(llvm::MCInst &Inst, unsigned Insn,
4015                            uint64_t Address, const void *Decoder) {
4016   DecodeStatus S = MCDisassembler::Success;
4017 
4018   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
4019   unsigned Rt2 = fieldFromInstruction32(Insn, 8, 4);
4020   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
4021   unsigned addr = fieldFromInstruction32(Insn, 0, 8);
4022   unsigned W = fieldFromInstruction32(Insn, 21, 1);
4023   unsigned U = fieldFromInstruction32(Insn, 23, 1);
4024   unsigned P = fieldFromInstruction32(Insn, 24, 1);
4025   bool writeback = (W == 1) | (P == 0);
4026 
4027   addr |= (U << 8) | (Rn << 9);
4028 
4029   if (writeback && (Rn == Rt || Rn == Rt2))
4030     Check(S, MCDisassembler::SoftFail);
4031 
4032   // Writeback operand
4033   if (!Check(S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
4034     return MCDisassembler::Fail;
4035   // Rt
4036   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
4037     return MCDisassembler::Fail;
4038   // Rt2
4039   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
4040     return MCDisassembler::Fail;
4041   // addr
4042   if (!Check(S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
4043     return MCDisassembler::Fail;
4044 
4045   return S;
4046 }
4047 
4048 static DecodeStatus DecodeT2Adr(llvm::MCInst &Inst, uint32_t Insn,
4049                                 uint64_t Address, const void *Decoder) {
4050   unsigned sign1 = fieldFromInstruction32(Insn, 21, 1);
4051   unsigned sign2 = fieldFromInstruction32(Insn, 23, 1);
4052   if (sign1 != sign2) return MCDisassembler::Fail;
4053 
4054   unsigned Val = fieldFromInstruction32(Insn, 0, 8);
4055   Val |= fieldFromInstruction32(Insn, 12, 3) << 8;
4056   Val |= fieldFromInstruction32(Insn, 26, 1) << 11;
4057   Val |= sign1 << 12;
4058   Inst.addOperand(MCOperand::CreateImm(SignExtend32<13>(Val)));
4059 
4060   return MCDisassembler::Success;
4061 }
4062 
4063 static DecodeStatus DecodeT2ShifterImmOperand(llvm::MCInst &Inst, uint32_t Val,
4064                                               uint64_t Address,
4065                                               const void *Decoder) {
4066   DecodeStatus S = MCDisassembler::Success;
4067 
4068   // Shift of "asr #32" is not allowed in Thumb2 mode.
4069   if (Val == 0x20) S = MCDisassembler::SoftFail;
4070   Inst.addOperand(MCOperand::CreateImm(Val));
4071   return S;
4072 }
4073 
4074 static DecodeStatus DecodeSwap(llvm::MCInst &Inst, unsigned Insn,
4075                                uint64_t Address, const void *Decoder) {
4076   unsigned Rt   = fieldFromInstruction32(Insn, 12, 4);
4077   unsigned Rt2  = fieldFromInstruction32(Insn, 0,  4);
4078   unsigned Rn   = fieldFromInstruction32(Insn, 16, 4);
4079   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
4080 
4081   if (pred == 0xF)
4082     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
4083 
4084   DecodeStatus S = MCDisassembler::Success;
4085   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
4086     return MCDisassembler::Fail;
4087   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt2, Address, Decoder)))
4088     return MCDisassembler::Fail;
4089   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
4090     return MCDisassembler::Fail;
4091   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4092     return MCDisassembler::Fail;
4093 
4094   return S;
4095 }
4096