xref: /llvm-project/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp (revision 05df460269f6a208a91197a5340bc8b8d144f030)
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   if (CountPopulation_32(Val) == 0) return MCDisassembler::Fail;
1115   for (unsigned i = 0; i < 16; ++i) {
1116     if (Val & (1 << i)) {
1117       if (!Check(S, DecodeGPRRegisterClass(Inst, i, Address, Decoder)))
1118         return MCDisassembler::Fail;
1119       // Writeback not allowed if Rn is in the target list.
1120       if (writebackLoad && writebackReg == Inst.end()[-1].getReg())
1121         Check(S, MCDisassembler::SoftFail);
1122     }
1123   }
1124 
1125   return S;
1126 }
1127 
1128 static DecodeStatus DecodeSPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
1129                                  uint64_t Address, const void *Decoder) {
1130   DecodeStatus S = MCDisassembler::Success;
1131 
1132   unsigned Vd = fieldFromInstruction32(Val, 8, 4);
1133   unsigned regs = Val & 0xFF;
1134 
1135   if (!Check(S, DecodeSPRRegisterClass(Inst, Vd, Address, Decoder)))
1136     return MCDisassembler::Fail;
1137   for (unsigned i = 0; i < (regs - 1); ++i) {
1138     if (!Check(S, DecodeSPRRegisterClass(Inst, ++Vd, Address, Decoder)))
1139       return MCDisassembler::Fail;
1140   }
1141 
1142   return S;
1143 }
1144 
1145 static DecodeStatus DecodeDPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
1146                                  uint64_t Address, const void *Decoder) {
1147   DecodeStatus S = MCDisassembler::Success;
1148 
1149   unsigned Vd = fieldFromInstruction32(Val, 8, 4);
1150   unsigned regs = (Val & 0xFF) / 2;
1151 
1152   if (!Check(S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)))
1153       return MCDisassembler::Fail;
1154   for (unsigned i = 0; i < (regs - 1); ++i) {
1155     if (!Check(S, DecodeDPRRegisterClass(Inst, ++Vd, Address, Decoder)))
1156       return MCDisassembler::Fail;
1157   }
1158 
1159   return S;
1160 }
1161 
1162 static DecodeStatus DecodeBitfieldMaskOperand(llvm::MCInst &Inst, unsigned Val,
1163                                       uint64_t Address, const void *Decoder) {
1164   // This operand encodes a mask of contiguous zeros between a specified MSB
1165   // and LSB.  To decode it, we create the mask of all bits MSB-and-lower,
1166   // the mask of all bits LSB-and-lower, and then xor them to create
1167   // the mask of that's all ones on [msb, lsb].  Finally we not it to
1168   // create the final mask.
1169   unsigned msb = fieldFromInstruction32(Val, 5, 5);
1170   unsigned lsb = fieldFromInstruction32(Val, 0, 5);
1171 
1172   DecodeStatus S = MCDisassembler::Success;
1173   if (lsb > msb) Check(S, MCDisassembler::SoftFail);
1174 
1175   uint32_t msb_mask = 0xFFFFFFFF;
1176   if (msb != 31) msb_mask = (1U << (msb+1)) - 1;
1177   uint32_t lsb_mask = (1U << lsb) - 1;
1178 
1179   Inst.addOperand(MCOperand::CreateImm(~(msb_mask ^ lsb_mask)));
1180   return S;
1181 }
1182 
1183 static DecodeStatus DecodeCopMemInstruction(llvm::MCInst &Inst, unsigned Insn,
1184                                   uint64_t Address, const void *Decoder) {
1185   DecodeStatus S = MCDisassembler::Success;
1186 
1187   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1188   unsigned CRd = fieldFromInstruction32(Insn, 12, 4);
1189   unsigned coproc = fieldFromInstruction32(Insn, 8, 4);
1190   unsigned imm = fieldFromInstruction32(Insn, 0, 8);
1191   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1192   unsigned U = fieldFromInstruction32(Insn, 23, 1);
1193 
1194   switch (Inst.getOpcode()) {
1195     case ARM::LDC_OFFSET:
1196     case ARM::LDC_PRE:
1197     case ARM::LDC_POST:
1198     case ARM::LDC_OPTION:
1199     case ARM::LDCL_OFFSET:
1200     case ARM::LDCL_PRE:
1201     case ARM::LDCL_POST:
1202     case ARM::LDCL_OPTION:
1203     case ARM::STC_OFFSET:
1204     case ARM::STC_PRE:
1205     case ARM::STC_POST:
1206     case ARM::STC_OPTION:
1207     case ARM::STCL_OFFSET:
1208     case ARM::STCL_PRE:
1209     case ARM::STCL_POST:
1210     case ARM::STCL_OPTION:
1211     case ARM::t2LDC_OFFSET:
1212     case ARM::t2LDC_PRE:
1213     case ARM::t2LDC_POST:
1214     case ARM::t2LDC_OPTION:
1215     case ARM::t2LDCL_OFFSET:
1216     case ARM::t2LDCL_PRE:
1217     case ARM::t2LDCL_POST:
1218     case ARM::t2LDCL_OPTION:
1219     case ARM::t2STC_OFFSET:
1220     case ARM::t2STC_PRE:
1221     case ARM::t2STC_POST:
1222     case ARM::t2STC_OPTION:
1223     case ARM::t2STCL_OFFSET:
1224     case ARM::t2STCL_PRE:
1225     case ARM::t2STCL_POST:
1226     case ARM::t2STCL_OPTION:
1227       if (coproc == 0xA || coproc == 0xB)
1228         return MCDisassembler::Fail;
1229       break;
1230     default:
1231       break;
1232   }
1233 
1234   Inst.addOperand(MCOperand::CreateImm(coproc));
1235   Inst.addOperand(MCOperand::CreateImm(CRd));
1236   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1237     return MCDisassembler::Fail;
1238 
1239   switch (Inst.getOpcode()) {
1240     case ARM::t2LDC2_OFFSET:
1241     case ARM::t2LDC2L_OFFSET:
1242     case ARM::t2LDC2_PRE:
1243     case ARM::t2LDC2L_PRE:
1244     case ARM::t2STC2_OFFSET:
1245     case ARM::t2STC2L_OFFSET:
1246     case ARM::t2STC2_PRE:
1247     case ARM::t2STC2L_PRE:
1248     case ARM::LDC2_OFFSET:
1249     case ARM::LDC2L_OFFSET:
1250     case ARM::LDC2_PRE:
1251     case ARM::LDC2L_PRE:
1252     case ARM::STC2_OFFSET:
1253     case ARM::STC2L_OFFSET:
1254     case ARM::STC2_PRE:
1255     case ARM::STC2L_PRE:
1256     case ARM::t2LDC_OFFSET:
1257     case ARM::t2LDCL_OFFSET:
1258     case ARM::t2LDC_PRE:
1259     case ARM::t2LDCL_PRE:
1260     case ARM::t2STC_OFFSET:
1261     case ARM::t2STCL_OFFSET:
1262     case ARM::t2STC_PRE:
1263     case ARM::t2STCL_PRE:
1264     case ARM::LDC_OFFSET:
1265     case ARM::LDCL_OFFSET:
1266     case ARM::LDC_PRE:
1267     case ARM::LDCL_PRE:
1268     case ARM::STC_OFFSET:
1269     case ARM::STCL_OFFSET:
1270     case ARM::STC_PRE:
1271     case ARM::STCL_PRE:
1272       imm = ARM_AM::getAM5Opc(U ? ARM_AM::add : ARM_AM::sub, imm);
1273       Inst.addOperand(MCOperand::CreateImm(imm));
1274       break;
1275     case ARM::t2LDC2_POST:
1276     case ARM::t2LDC2L_POST:
1277     case ARM::t2STC2_POST:
1278     case ARM::t2STC2L_POST:
1279     case ARM::LDC2_POST:
1280     case ARM::LDC2L_POST:
1281     case ARM::STC2_POST:
1282     case ARM::STC2L_POST:
1283     case ARM::t2LDC_POST:
1284     case ARM::t2LDCL_POST:
1285     case ARM::t2STC_POST:
1286     case ARM::t2STCL_POST:
1287     case ARM::LDC_POST:
1288     case ARM::LDCL_POST:
1289     case ARM::STC_POST:
1290     case ARM::STCL_POST:
1291       imm |= U << 8;
1292       // fall through.
1293     default:
1294       // The 'option' variant doesn't encode 'U' in the immediate since
1295       // the immediate is unsigned [0,255].
1296       Inst.addOperand(MCOperand::CreateImm(imm));
1297       break;
1298   }
1299 
1300   switch (Inst.getOpcode()) {
1301     case ARM::LDC_OFFSET:
1302     case ARM::LDC_PRE:
1303     case ARM::LDC_POST:
1304     case ARM::LDC_OPTION:
1305     case ARM::LDCL_OFFSET:
1306     case ARM::LDCL_PRE:
1307     case ARM::LDCL_POST:
1308     case ARM::LDCL_OPTION:
1309     case ARM::STC_OFFSET:
1310     case ARM::STC_PRE:
1311     case ARM::STC_POST:
1312     case ARM::STC_OPTION:
1313     case ARM::STCL_OFFSET:
1314     case ARM::STCL_PRE:
1315     case ARM::STCL_POST:
1316     case ARM::STCL_OPTION:
1317       if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1318         return MCDisassembler::Fail;
1319       break;
1320     default:
1321       break;
1322   }
1323 
1324   return S;
1325 }
1326 
1327 static DecodeStatus
1328 DecodeAddrMode2IdxInstruction(llvm::MCInst &Inst, unsigned Insn,
1329                               uint64_t Address, const void *Decoder) {
1330   DecodeStatus S = MCDisassembler::Success;
1331 
1332   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1333   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
1334   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1335   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
1336   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1337   unsigned reg = fieldFromInstruction32(Insn, 25, 1);
1338   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1339   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1340 
1341   // On stores, the writeback operand precedes Rt.
1342   switch (Inst.getOpcode()) {
1343     case ARM::STR_POST_IMM:
1344     case ARM::STR_POST_REG:
1345     case ARM::STRB_POST_IMM:
1346     case ARM::STRB_POST_REG:
1347     case ARM::STRT_POST_REG:
1348     case ARM::STRT_POST_IMM:
1349     case ARM::STRBT_POST_REG:
1350     case ARM::STRBT_POST_IMM:
1351       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1352         return MCDisassembler::Fail;
1353       break;
1354     default:
1355       break;
1356   }
1357 
1358   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
1359     return MCDisassembler::Fail;
1360 
1361   // On loads, the writeback operand comes after Rt.
1362   switch (Inst.getOpcode()) {
1363     case ARM::LDR_POST_IMM:
1364     case ARM::LDR_POST_REG:
1365     case ARM::LDRB_POST_IMM:
1366     case ARM::LDRB_POST_REG:
1367     case ARM::LDRBT_POST_REG:
1368     case ARM::LDRBT_POST_IMM:
1369     case ARM::LDRT_POST_REG:
1370     case ARM::LDRT_POST_IMM:
1371       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1372         return MCDisassembler::Fail;
1373       break;
1374     default:
1375       break;
1376   }
1377 
1378   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1379     return MCDisassembler::Fail;
1380 
1381   ARM_AM::AddrOpc Op = ARM_AM::add;
1382   if (!fieldFromInstruction32(Insn, 23, 1))
1383     Op = ARM_AM::sub;
1384 
1385   bool writeback = (P == 0) || (W == 1);
1386   unsigned idx_mode = 0;
1387   if (P && writeback)
1388     idx_mode = ARMII::IndexModePre;
1389   else if (!P && writeback)
1390     idx_mode = ARMII::IndexModePost;
1391 
1392   if (writeback && (Rn == 15 || Rn == Rt))
1393     S = MCDisassembler::SoftFail; // UNPREDICTABLE
1394 
1395   if (reg) {
1396     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1397       return MCDisassembler::Fail;
1398     ARM_AM::ShiftOpc Opc = ARM_AM::lsl;
1399     switch( fieldFromInstruction32(Insn, 5, 2)) {
1400       case 0:
1401         Opc = ARM_AM::lsl;
1402         break;
1403       case 1:
1404         Opc = ARM_AM::lsr;
1405         break;
1406       case 2:
1407         Opc = ARM_AM::asr;
1408         break;
1409       case 3:
1410         Opc = ARM_AM::ror;
1411         break;
1412       default:
1413         return MCDisassembler::Fail;
1414     }
1415     unsigned amt = fieldFromInstruction32(Insn, 7, 5);
1416     unsigned imm = ARM_AM::getAM2Opc(Op, amt, Opc, idx_mode);
1417 
1418     Inst.addOperand(MCOperand::CreateImm(imm));
1419   } else {
1420     Inst.addOperand(MCOperand::CreateReg(0));
1421     unsigned tmp = ARM_AM::getAM2Opc(Op, imm, ARM_AM::lsl, idx_mode);
1422     Inst.addOperand(MCOperand::CreateImm(tmp));
1423   }
1424 
1425   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1426     return MCDisassembler::Fail;
1427 
1428   return S;
1429 }
1430 
1431 static DecodeStatus DecodeSORegMemOperand(llvm::MCInst &Inst, unsigned Val,
1432                                   uint64_t Address, const void *Decoder) {
1433   DecodeStatus S = MCDisassembler::Success;
1434 
1435   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
1436   unsigned Rm = fieldFromInstruction32(Val,  0, 4);
1437   unsigned type = fieldFromInstruction32(Val, 5, 2);
1438   unsigned imm = fieldFromInstruction32(Val, 7, 5);
1439   unsigned U = fieldFromInstruction32(Val, 12, 1);
1440 
1441   ARM_AM::ShiftOpc ShOp = ARM_AM::lsl;
1442   switch (type) {
1443     case 0:
1444       ShOp = ARM_AM::lsl;
1445       break;
1446     case 1:
1447       ShOp = ARM_AM::lsr;
1448       break;
1449     case 2:
1450       ShOp = ARM_AM::asr;
1451       break;
1452     case 3:
1453       ShOp = ARM_AM::ror;
1454       break;
1455   }
1456 
1457   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1458     return MCDisassembler::Fail;
1459   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1460     return MCDisassembler::Fail;
1461   unsigned shift;
1462   if (U)
1463     shift = ARM_AM::getAM2Opc(ARM_AM::add, imm, ShOp);
1464   else
1465     shift = ARM_AM::getAM2Opc(ARM_AM::sub, imm, ShOp);
1466   Inst.addOperand(MCOperand::CreateImm(shift));
1467 
1468   return S;
1469 }
1470 
1471 static DecodeStatus
1472 DecodeAddrMode3Instruction(llvm::MCInst &Inst, unsigned Insn,
1473                            uint64_t Address, const void *Decoder) {
1474   DecodeStatus S = MCDisassembler::Success;
1475 
1476   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
1477   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1478   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1479   unsigned type = fieldFromInstruction32(Insn, 22, 1);
1480   unsigned imm = fieldFromInstruction32(Insn, 8, 4);
1481   unsigned U = ((~fieldFromInstruction32(Insn, 23, 1)) & 1) << 8;
1482   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1483   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1484   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1485 
1486   bool writeback = (W == 1) | (P == 0);
1487 
1488   // For {LD,ST}RD, Rt must be even, else undefined.
1489   switch (Inst.getOpcode()) {
1490     case ARM::STRD:
1491     case ARM::STRD_PRE:
1492     case ARM::STRD_POST:
1493     case ARM::LDRD:
1494     case ARM::LDRD_PRE:
1495     case ARM::LDRD_POST:
1496       if (Rt & 0x1) return MCDisassembler::Fail;
1497       break;
1498     default:
1499       break;
1500   }
1501 
1502   if (writeback) { // Writeback
1503     if (P)
1504       U |= ARMII::IndexModePre << 9;
1505     else
1506       U |= ARMII::IndexModePost << 9;
1507 
1508     // On stores, the writeback operand precedes Rt.
1509     switch (Inst.getOpcode()) {
1510     case ARM::STRD:
1511     case ARM::STRD_PRE:
1512     case ARM::STRD_POST:
1513     case ARM::STRH:
1514     case ARM::STRH_PRE:
1515     case ARM::STRH_POST:
1516       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1517         return MCDisassembler::Fail;
1518       break;
1519     default:
1520       break;
1521     }
1522   }
1523 
1524   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
1525     return MCDisassembler::Fail;
1526   switch (Inst.getOpcode()) {
1527     case ARM::STRD:
1528     case ARM::STRD_PRE:
1529     case ARM::STRD_POST:
1530     case ARM::LDRD:
1531     case ARM::LDRD_PRE:
1532     case ARM::LDRD_POST:
1533       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
1534         return MCDisassembler::Fail;
1535       break;
1536     default:
1537       break;
1538   }
1539 
1540   if (writeback) {
1541     // On loads, the writeback operand comes after Rt.
1542     switch (Inst.getOpcode()) {
1543     case ARM::LDRD:
1544     case ARM::LDRD_PRE:
1545     case ARM::LDRD_POST:
1546     case ARM::LDRH:
1547     case ARM::LDRH_PRE:
1548     case ARM::LDRH_POST:
1549     case ARM::LDRSH:
1550     case ARM::LDRSH_PRE:
1551     case ARM::LDRSH_POST:
1552     case ARM::LDRSB:
1553     case ARM::LDRSB_PRE:
1554     case ARM::LDRSB_POST:
1555     case ARM::LDRHTr:
1556     case ARM::LDRSBTr:
1557       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1558         return MCDisassembler::Fail;
1559       break;
1560     default:
1561       break;
1562     }
1563   }
1564 
1565   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1566     return MCDisassembler::Fail;
1567 
1568   if (type) {
1569     Inst.addOperand(MCOperand::CreateReg(0));
1570     Inst.addOperand(MCOperand::CreateImm(U | (imm << 4) | Rm));
1571   } else {
1572     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1573     return MCDisassembler::Fail;
1574     Inst.addOperand(MCOperand::CreateImm(U));
1575   }
1576 
1577   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1578     return MCDisassembler::Fail;
1579 
1580   return S;
1581 }
1582 
1583 static DecodeStatus DecodeRFEInstruction(llvm::MCInst &Inst, unsigned Insn,
1584                                  uint64_t Address, const void *Decoder) {
1585   DecodeStatus S = MCDisassembler::Success;
1586 
1587   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1588   unsigned mode = fieldFromInstruction32(Insn, 23, 2);
1589 
1590   switch (mode) {
1591     case 0:
1592       mode = ARM_AM::da;
1593       break;
1594     case 1:
1595       mode = ARM_AM::ia;
1596       break;
1597     case 2:
1598       mode = ARM_AM::db;
1599       break;
1600     case 3:
1601       mode = ARM_AM::ib;
1602       break;
1603   }
1604 
1605   Inst.addOperand(MCOperand::CreateImm(mode));
1606   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1607     return MCDisassembler::Fail;
1608 
1609   return S;
1610 }
1611 
1612 static DecodeStatus DecodeMemMultipleWritebackInstruction(llvm::MCInst &Inst,
1613                                   unsigned Insn,
1614                                   uint64_t Address, const void *Decoder) {
1615   DecodeStatus S = MCDisassembler::Success;
1616 
1617   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1618   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1619   unsigned reglist = fieldFromInstruction32(Insn, 0, 16);
1620 
1621   if (pred == 0xF) {
1622     switch (Inst.getOpcode()) {
1623       case ARM::LDMDA:
1624         Inst.setOpcode(ARM::RFEDA);
1625         break;
1626       case ARM::LDMDA_UPD:
1627         Inst.setOpcode(ARM::RFEDA_UPD);
1628         break;
1629       case ARM::LDMDB:
1630         Inst.setOpcode(ARM::RFEDB);
1631         break;
1632       case ARM::LDMDB_UPD:
1633         Inst.setOpcode(ARM::RFEDB_UPD);
1634         break;
1635       case ARM::LDMIA:
1636         Inst.setOpcode(ARM::RFEIA);
1637         break;
1638       case ARM::LDMIA_UPD:
1639         Inst.setOpcode(ARM::RFEIA_UPD);
1640         break;
1641       case ARM::LDMIB:
1642         Inst.setOpcode(ARM::RFEIB);
1643         break;
1644       case ARM::LDMIB_UPD:
1645         Inst.setOpcode(ARM::RFEIB_UPD);
1646         break;
1647       case ARM::STMDA:
1648         Inst.setOpcode(ARM::SRSDA);
1649         break;
1650       case ARM::STMDA_UPD:
1651         Inst.setOpcode(ARM::SRSDA_UPD);
1652         break;
1653       case ARM::STMDB:
1654         Inst.setOpcode(ARM::SRSDB);
1655         break;
1656       case ARM::STMDB_UPD:
1657         Inst.setOpcode(ARM::SRSDB_UPD);
1658         break;
1659       case ARM::STMIA:
1660         Inst.setOpcode(ARM::SRSIA);
1661         break;
1662       case ARM::STMIA_UPD:
1663         Inst.setOpcode(ARM::SRSIA_UPD);
1664         break;
1665       case ARM::STMIB:
1666         Inst.setOpcode(ARM::SRSIB);
1667         break;
1668       case ARM::STMIB_UPD:
1669         Inst.setOpcode(ARM::SRSIB_UPD);
1670         break;
1671       default:
1672         if (!Check(S, MCDisassembler::Fail)) return MCDisassembler::Fail;
1673     }
1674 
1675     // For stores (which become SRS's, the only operand is the mode.
1676     if (fieldFromInstruction32(Insn, 20, 1) == 0) {
1677       Inst.addOperand(
1678           MCOperand::CreateImm(fieldFromInstruction32(Insn, 0, 4)));
1679       return S;
1680     }
1681 
1682     return DecodeRFEInstruction(Inst, Insn, Address, Decoder);
1683   }
1684 
1685   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1686     return MCDisassembler::Fail;
1687   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1688     return MCDisassembler::Fail; // Tied
1689   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1690     return MCDisassembler::Fail;
1691   if (!Check(S, DecodeRegListOperand(Inst, reglist, Address, Decoder)))
1692     return MCDisassembler::Fail;
1693 
1694   return S;
1695 }
1696 
1697 static DecodeStatus DecodeCPSInstruction(llvm::MCInst &Inst, unsigned Insn,
1698                                  uint64_t Address, const void *Decoder) {
1699   unsigned imod = fieldFromInstruction32(Insn, 18, 2);
1700   unsigned M = fieldFromInstruction32(Insn, 17, 1);
1701   unsigned iflags = fieldFromInstruction32(Insn, 6, 3);
1702   unsigned mode = fieldFromInstruction32(Insn, 0, 5);
1703 
1704   DecodeStatus S = MCDisassembler::Success;
1705 
1706   // imod == '01' --> UNPREDICTABLE
1707   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
1708   // return failure here.  The '01' imod value is unprintable, so there's
1709   // nothing useful we could do even if we returned UNPREDICTABLE.
1710 
1711   if (imod == 1) return MCDisassembler::Fail;
1712 
1713   if (imod && M) {
1714     Inst.setOpcode(ARM::CPS3p);
1715     Inst.addOperand(MCOperand::CreateImm(imod));
1716     Inst.addOperand(MCOperand::CreateImm(iflags));
1717     Inst.addOperand(MCOperand::CreateImm(mode));
1718   } else if (imod && !M) {
1719     Inst.setOpcode(ARM::CPS2p);
1720     Inst.addOperand(MCOperand::CreateImm(imod));
1721     Inst.addOperand(MCOperand::CreateImm(iflags));
1722     if (mode) S = MCDisassembler::SoftFail;
1723   } else if (!imod && M) {
1724     Inst.setOpcode(ARM::CPS1p);
1725     Inst.addOperand(MCOperand::CreateImm(mode));
1726     if (iflags) S = MCDisassembler::SoftFail;
1727   } else {
1728     // imod == '00' && M == '0' --> UNPREDICTABLE
1729     Inst.setOpcode(ARM::CPS1p);
1730     Inst.addOperand(MCOperand::CreateImm(mode));
1731     S = MCDisassembler::SoftFail;
1732   }
1733 
1734   return S;
1735 }
1736 
1737 static DecodeStatus DecodeT2CPSInstruction(llvm::MCInst &Inst, unsigned Insn,
1738                                  uint64_t Address, const void *Decoder) {
1739   unsigned imod = fieldFromInstruction32(Insn, 9, 2);
1740   unsigned M = fieldFromInstruction32(Insn, 8, 1);
1741   unsigned iflags = fieldFromInstruction32(Insn, 5, 3);
1742   unsigned mode = fieldFromInstruction32(Insn, 0, 5);
1743 
1744   DecodeStatus S = MCDisassembler::Success;
1745 
1746   // imod == '01' --> UNPREDICTABLE
1747   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
1748   // return failure here.  The '01' imod value is unprintable, so there's
1749   // nothing useful we could do even if we returned UNPREDICTABLE.
1750 
1751   if (imod == 1) return MCDisassembler::Fail;
1752 
1753   if (imod && M) {
1754     Inst.setOpcode(ARM::t2CPS3p);
1755     Inst.addOperand(MCOperand::CreateImm(imod));
1756     Inst.addOperand(MCOperand::CreateImm(iflags));
1757     Inst.addOperand(MCOperand::CreateImm(mode));
1758   } else if (imod && !M) {
1759     Inst.setOpcode(ARM::t2CPS2p);
1760     Inst.addOperand(MCOperand::CreateImm(imod));
1761     Inst.addOperand(MCOperand::CreateImm(iflags));
1762     if (mode) S = MCDisassembler::SoftFail;
1763   } else if (!imod && M) {
1764     Inst.setOpcode(ARM::t2CPS1p);
1765     Inst.addOperand(MCOperand::CreateImm(mode));
1766     if (iflags) S = MCDisassembler::SoftFail;
1767   } else {
1768     // imod == '00' && M == '0' --> UNPREDICTABLE
1769     Inst.setOpcode(ARM::t2CPS1p);
1770     Inst.addOperand(MCOperand::CreateImm(mode));
1771     S = MCDisassembler::SoftFail;
1772   }
1773 
1774   return S;
1775 }
1776 
1777 static DecodeStatus DecodeT2MOVTWInstruction(llvm::MCInst &Inst, unsigned Insn,
1778                                  uint64_t Address, const void *Decoder) {
1779   DecodeStatus S = MCDisassembler::Success;
1780 
1781   unsigned Rd = fieldFromInstruction32(Insn, 8, 4);
1782   unsigned imm = 0;
1783 
1784   imm |= (fieldFromInstruction32(Insn, 0, 8) << 0);
1785   imm |= (fieldFromInstruction32(Insn, 12, 3) << 8);
1786   imm |= (fieldFromInstruction32(Insn, 16, 4) << 12);
1787   imm |= (fieldFromInstruction32(Insn, 26, 1) << 11);
1788 
1789   if (Inst.getOpcode() == ARM::t2MOVTi16)
1790     if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
1791       return MCDisassembler::Fail;
1792   if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
1793     return MCDisassembler::Fail;
1794 
1795   if (!tryAddingSymbolicOperand(Address, imm, false, 4, Inst, Decoder))
1796     Inst.addOperand(MCOperand::CreateImm(imm));
1797 
1798   return S;
1799 }
1800 
1801 static DecodeStatus DecodeArmMOVTWInstruction(llvm::MCInst &Inst, unsigned Insn,
1802                                  uint64_t Address, const void *Decoder) {
1803   DecodeStatus S = MCDisassembler::Success;
1804 
1805   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
1806   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1807   unsigned imm = 0;
1808 
1809   imm |= (fieldFromInstruction32(Insn, 0, 12) << 0);
1810   imm |= (fieldFromInstruction32(Insn, 16, 4) << 12);
1811 
1812   if (Inst.getOpcode() == ARM::MOVTi16)
1813     if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
1814       return MCDisassembler::Fail;
1815   if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
1816     return MCDisassembler::Fail;
1817 
1818   if (!tryAddingSymbolicOperand(Address, imm, false, 4, Inst, Decoder))
1819     Inst.addOperand(MCOperand::CreateImm(imm));
1820 
1821   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1822     return MCDisassembler::Fail;
1823 
1824   return S;
1825 }
1826 
1827 static DecodeStatus DecodeSMLAInstruction(llvm::MCInst &Inst, unsigned Insn,
1828                                  uint64_t Address, const void *Decoder) {
1829   DecodeStatus S = MCDisassembler::Success;
1830 
1831   unsigned Rd = fieldFromInstruction32(Insn, 16, 4);
1832   unsigned Rn = fieldFromInstruction32(Insn, 0, 4);
1833   unsigned Rm = fieldFromInstruction32(Insn, 8, 4);
1834   unsigned Ra = fieldFromInstruction32(Insn, 12, 4);
1835   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1836 
1837   if (pred == 0xF)
1838     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
1839 
1840   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
1841     return MCDisassembler::Fail;
1842   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
1843     return MCDisassembler::Fail;
1844   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1845     return MCDisassembler::Fail;
1846   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Ra, Address, Decoder)))
1847     return MCDisassembler::Fail;
1848 
1849   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1850     return MCDisassembler::Fail;
1851 
1852   return S;
1853 }
1854 
1855 static DecodeStatus DecodeAddrModeImm12Operand(llvm::MCInst &Inst, unsigned Val,
1856                            uint64_t Address, const void *Decoder) {
1857   DecodeStatus S = MCDisassembler::Success;
1858 
1859   unsigned add = fieldFromInstruction32(Val, 12, 1);
1860   unsigned imm = fieldFromInstruction32(Val, 0, 12);
1861   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
1862 
1863   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1864     return MCDisassembler::Fail;
1865 
1866   if (!add) imm *= -1;
1867   if (imm == 0 && !add) imm = INT32_MIN;
1868   Inst.addOperand(MCOperand::CreateImm(imm));
1869   if (Rn == 15)
1870     tryAddingPcLoadReferenceComment(Address, Address + imm + 8, Decoder);
1871 
1872   return S;
1873 }
1874 
1875 static DecodeStatus DecodeAddrMode5Operand(llvm::MCInst &Inst, unsigned Val,
1876                                    uint64_t Address, const void *Decoder) {
1877   DecodeStatus S = MCDisassembler::Success;
1878 
1879   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
1880   unsigned U = fieldFromInstruction32(Val, 8, 1);
1881   unsigned imm = fieldFromInstruction32(Val, 0, 8);
1882 
1883   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1884     return MCDisassembler::Fail;
1885 
1886   if (U)
1887     Inst.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(ARM_AM::add, imm)));
1888   else
1889     Inst.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(ARM_AM::sub, imm)));
1890 
1891   return S;
1892 }
1893 
1894 static DecodeStatus DecodeAddrMode7Operand(llvm::MCInst &Inst, unsigned Val,
1895                                    uint64_t Address, const void *Decoder) {
1896   return DecodeGPRRegisterClass(Inst, Val, Address, Decoder);
1897 }
1898 
1899 static DecodeStatus
1900 DecodeBranchImmInstruction(llvm::MCInst &Inst, unsigned Insn,
1901                            uint64_t Address, const void *Decoder) {
1902   DecodeStatus S = MCDisassembler::Success;
1903 
1904   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1905   unsigned imm = fieldFromInstruction32(Insn, 0, 24) << 2;
1906 
1907   if (pred == 0xF) {
1908     Inst.setOpcode(ARM::BLXi);
1909     imm |= fieldFromInstruction32(Insn, 24, 1) << 1;
1910     Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(imm)));
1911     return S;
1912   }
1913 
1914   if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<26>(imm) + 8, true,
1915                                 4, Inst, Decoder))
1916     Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(imm)));
1917   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1918     return MCDisassembler::Fail;
1919 
1920   return S;
1921 }
1922 
1923 
1924 static DecodeStatus DecodeVCVTImmOperand(llvm::MCInst &Inst, unsigned Val,
1925                                  uint64_t Address, const void *Decoder) {
1926   Inst.addOperand(MCOperand::CreateImm(64 - Val));
1927   return MCDisassembler::Success;
1928 }
1929 
1930 static DecodeStatus DecodeAddrMode6Operand(llvm::MCInst &Inst, unsigned Val,
1931                                    uint64_t Address, const void *Decoder) {
1932   DecodeStatus S = MCDisassembler::Success;
1933 
1934   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
1935   unsigned align = fieldFromInstruction32(Val, 4, 2);
1936 
1937   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1938     return MCDisassembler::Fail;
1939   if (!align)
1940     Inst.addOperand(MCOperand::CreateImm(0));
1941   else
1942     Inst.addOperand(MCOperand::CreateImm(4 << align));
1943 
1944   return S;
1945 }
1946 
1947 static DecodeStatus DecodeVLDInstruction(llvm::MCInst &Inst, unsigned Insn,
1948                                    uint64_t Address, const void *Decoder) {
1949   DecodeStatus S = MCDisassembler::Success;
1950 
1951   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
1952   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
1953   unsigned wb = fieldFromInstruction32(Insn, 16, 4);
1954   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1955   Rn |= fieldFromInstruction32(Insn, 4, 2) << 4;
1956   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1957 
1958   // First output register
1959   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
1960     return MCDisassembler::Fail;
1961 
1962   // Second output register
1963   switch (Inst.getOpcode()) {
1964     case ARM::VLD3d8:
1965     case ARM::VLD3d16:
1966     case ARM::VLD3d32:
1967     case ARM::VLD3d8_UPD:
1968     case ARM::VLD3d16_UPD:
1969     case ARM::VLD3d32_UPD:
1970     case ARM::VLD4d8:
1971     case ARM::VLD4d16:
1972     case ARM::VLD4d32:
1973     case ARM::VLD4d8_UPD:
1974     case ARM::VLD4d16_UPD:
1975     case ARM::VLD4d32_UPD:
1976       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
1977         return MCDisassembler::Fail;
1978       break;
1979     case ARM::VLD3q8:
1980     case ARM::VLD3q16:
1981     case ARM::VLD3q32:
1982     case ARM::VLD3q8_UPD:
1983     case ARM::VLD3q16_UPD:
1984     case ARM::VLD3q32_UPD:
1985     case ARM::VLD4q8:
1986     case ARM::VLD4q16:
1987     case ARM::VLD4q32:
1988     case ARM::VLD4q8_UPD:
1989     case ARM::VLD4q16_UPD:
1990     case ARM::VLD4q32_UPD:
1991       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
1992         return MCDisassembler::Fail;
1993     default:
1994       break;
1995   }
1996 
1997   // Third output register
1998   switch(Inst.getOpcode()) {
1999     case ARM::VLD3d8:
2000     case ARM::VLD3d16:
2001     case ARM::VLD3d32:
2002     case ARM::VLD3d8_UPD:
2003     case ARM::VLD3d16_UPD:
2004     case ARM::VLD3d32_UPD:
2005     case ARM::VLD4d8:
2006     case ARM::VLD4d16:
2007     case ARM::VLD4d32:
2008     case ARM::VLD4d8_UPD:
2009     case ARM::VLD4d16_UPD:
2010     case ARM::VLD4d32_UPD:
2011       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2012         return MCDisassembler::Fail;
2013       break;
2014     case ARM::VLD3q8:
2015     case ARM::VLD3q16:
2016     case ARM::VLD3q32:
2017     case ARM::VLD3q8_UPD:
2018     case ARM::VLD3q16_UPD:
2019     case ARM::VLD3q32_UPD:
2020     case ARM::VLD4q8:
2021     case ARM::VLD4q16:
2022     case ARM::VLD4q32:
2023     case ARM::VLD4q8_UPD:
2024     case ARM::VLD4q16_UPD:
2025     case ARM::VLD4q32_UPD:
2026       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
2027         return MCDisassembler::Fail;
2028       break;
2029     default:
2030       break;
2031   }
2032 
2033   // Fourth output register
2034   switch (Inst.getOpcode()) {
2035     case ARM::VLD4d8:
2036     case ARM::VLD4d16:
2037     case ARM::VLD4d32:
2038     case ARM::VLD4d8_UPD:
2039     case ARM::VLD4d16_UPD:
2040     case ARM::VLD4d32_UPD:
2041       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
2042         return MCDisassembler::Fail;
2043       break;
2044     case ARM::VLD4q8:
2045     case ARM::VLD4q16:
2046     case ARM::VLD4q32:
2047     case ARM::VLD4q8_UPD:
2048     case ARM::VLD4q16_UPD:
2049     case ARM::VLD4q32_UPD:
2050       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
2051         return MCDisassembler::Fail;
2052       break;
2053     default:
2054       break;
2055   }
2056 
2057   // Writeback operand
2058   switch (Inst.getOpcode()) {
2059     case ARM::VLD1d8wb_fixed:
2060     case ARM::VLD1d16wb_fixed:
2061     case ARM::VLD1d32wb_fixed:
2062     case ARM::VLD1d64wb_fixed:
2063     case ARM::VLD1d8wb_register:
2064     case ARM::VLD1d16wb_register:
2065     case ARM::VLD1d32wb_register:
2066     case ARM::VLD1d64wb_register:
2067     case ARM::VLD1q8wb_fixed:
2068     case ARM::VLD1q16wb_fixed:
2069     case ARM::VLD1q32wb_fixed:
2070     case ARM::VLD1q64wb_fixed:
2071     case ARM::VLD1q8wb_register:
2072     case ARM::VLD1q16wb_register:
2073     case ARM::VLD1q32wb_register:
2074     case ARM::VLD1q64wb_register:
2075     case ARM::VLD1d8Twb_fixed:
2076     case ARM::VLD1d8Twb_register:
2077     case ARM::VLD1d16Twb_fixed:
2078     case ARM::VLD1d16Twb_register:
2079     case ARM::VLD1d32Twb_fixed:
2080     case ARM::VLD1d32Twb_register:
2081     case ARM::VLD1d64Twb_fixed:
2082     case ARM::VLD1d64Twb_register:
2083     case ARM::VLD1d8Qwb_fixed:
2084     case ARM::VLD1d8Qwb_register:
2085     case ARM::VLD1d16Qwb_fixed:
2086     case ARM::VLD1d16Qwb_register:
2087     case ARM::VLD1d32Qwb_fixed:
2088     case ARM::VLD1d32Qwb_register:
2089     case ARM::VLD1d64Qwb_fixed:
2090     case ARM::VLD1d64Qwb_register:
2091     case ARM::VLD2d8_UPD:
2092     case ARM::VLD2d16_UPD:
2093     case ARM::VLD2d32_UPD:
2094     case ARM::VLD2q8_UPD:
2095     case ARM::VLD2q16_UPD:
2096     case ARM::VLD2q32_UPD:
2097     case ARM::VLD2b8_UPD:
2098     case ARM::VLD2b16_UPD:
2099     case ARM::VLD2b32_UPD:
2100     case ARM::VLD3d8_UPD:
2101     case ARM::VLD3d16_UPD:
2102     case ARM::VLD3d32_UPD:
2103     case ARM::VLD3q8_UPD:
2104     case ARM::VLD3q16_UPD:
2105     case ARM::VLD3q32_UPD:
2106     case ARM::VLD4d8_UPD:
2107     case ARM::VLD4d16_UPD:
2108     case ARM::VLD4d32_UPD:
2109     case ARM::VLD4q8_UPD:
2110     case ARM::VLD4q16_UPD:
2111     case ARM::VLD4q32_UPD:
2112       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
2113         return MCDisassembler::Fail;
2114       break;
2115     default:
2116       break;
2117   }
2118 
2119   // AddrMode6 Base (register+alignment)
2120   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
2121     return MCDisassembler::Fail;
2122 
2123   // AddrMode6 Offset (register)
2124   switch (Inst.getOpcode()) {
2125   default:
2126     // The below have been updated to have explicit am6offset split
2127     // between fixed and register offset. For those instructions not
2128     // yet updated, we need to add an additional reg0 operand for the
2129     // fixed variant.
2130     //
2131     // The fixed offset encodes as Rm == 0xd, so we check for that.
2132     if (Rm == 0xd) {
2133       Inst.addOperand(MCOperand::CreateReg(0));
2134       break;
2135     }
2136     // Fall through to handle the register offset variant.
2137   case ARM::VLD1d8wb_fixed:
2138   case ARM::VLD1d16wb_fixed:
2139   case ARM::VLD1d32wb_fixed:
2140   case ARM::VLD1d64wb_fixed:
2141   case ARM::VLD1d8Twb_fixed:
2142   case ARM::VLD1d16Twb_fixed:
2143   case ARM::VLD1d32Twb_fixed:
2144   case ARM::VLD1d64Twb_fixed:
2145   case ARM::VLD1d8Qwb_fixed:
2146   case ARM::VLD1d16Qwb_fixed:
2147   case ARM::VLD1d32Qwb_fixed:
2148   case ARM::VLD1d64Qwb_fixed:
2149   case ARM::VLD1d8wb_register:
2150   case ARM::VLD1d16wb_register:
2151   case ARM::VLD1d32wb_register:
2152   case ARM::VLD1d64wb_register:
2153   case ARM::VLD1q8wb_fixed:
2154   case ARM::VLD1q16wb_fixed:
2155   case ARM::VLD1q32wb_fixed:
2156   case ARM::VLD1q64wb_fixed:
2157   case ARM::VLD1q8wb_register:
2158   case ARM::VLD1q16wb_register:
2159   case ARM::VLD1q32wb_register:
2160   case ARM::VLD1q64wb_register:
2161     // The fixed offset post-increment encodes Rm == 0xd. The no-writeback
2162     // variant encodes Rm == 0xf. Anything else is a register offset post-
2163     // increment and we need to add the register operand to the instruction.
2164     if (Rm != 0xD && Rm != 0xF &&
2165         !Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2166       return MCDisassembler::Fail;
2167     break;
2168   }
2169 
2170   return S;
2171 }
2172 
2173 static DecodeStatus DecodeVSTInstruction(llvm::MCInst &Inst, unsigned Insn,
2174                                  uint64_t Address, const void *Decoder) {
2175   DecodeStatus S = MCDisassembler::Success;
2176 
2177   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2178   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2179   unsigned wb = fieldFromInstruction32(Insn, 16, 4);
2180   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2181   Rn |= fieldFromInstruction32(Insn, 4, 2) << 4;
2182   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2183 
2184   // Writeback Operand
2185   switch (Inst.getOpcode()) {
2186     case ARM::VST1d8wb_fixed:
2187     case ARM::VST1d16wb_fixed:
2188     case ARM::VST1d32wb_fixed:
2189     case ARM::VST1d64wb_fixed:
2190     case ARM::VST1d8wb_register:
2191     case ARM::VST1d16wb_register:
2192     case ARM::VST1d32wb_register:
2193     case ARM::VST1d64wb_register:
2194     case ARM::VST1q8wb_fixed:
2195     case ARM::VST1q16wb_fixed:
2196     case ARM::VST1q32wb_fixed:
2197     case ARM::VST1q64wb_fixed:
2198     case ARM::VST1q8wb_register:
2199     case ARM::VST1q16wb_register:
2200     case ARM::VST1q32wb_register:
2201     case ARM::VST1q64wb_register:
2202     case ARM::VST1d8T_UPD:
2203     case ARM::VST1d16T_UPD:
2204     case ARM::VST1d32T_UPD:
2205     case ARM::VST1d64T_UPD:
2206     case ARM::VST1d8Q_UPD:
2207     case ARM::VST1d16Q_UPD:
2208     case ARM::VST1d32Q_UPD:
2209     case ARM::VST1d64Q_UPD:
2210     case ARM::VST2d8_UPD:
2211     case ARM::VST2d16_UPD:
2212     case ARM::VST2d32_UPD:
2213     case ARM::VST2q8_UPD:
2214     case ARM::VST2q16_UPD:
2215     case ARM::VST2q32_UPD:
2216     case ARM::VST2b8_UPD:
2217     case ARM::VST2b16_UPD:
2218     case ARM::VST2b32_UPD:
2219     case ARM::VST3d8_UPD:
2220     case ARM::VST3d16_UPD:
2221     case ARM::VST3d32_UPD:
2222     case ARM::VST3q8_UPD:
2223     case ARM::VST3q16_UPD:
2224     case ARM::VST3q32_UPD:
2225     case ARM::VST4d8_UPD:
2226     case ARM::VST4d16_UPD:
2227     case ARM::VST4d32_UPD:
2228     case ARM::VST4q8_UPD:
2229     case ARM::VST4q16_UPD:
2230     case ARM::VST4q32_UPD:
2231       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
2232         return MCDisassembler::Fail;
2233       break;
2234     default:
2235       break;
2236   }
2237 
2238   // AddrMode6 Base (register+alignment)
2239   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
2240     return MCDisassembler::Fail;
2241 
2242   // AddrMode6 Offset (register)
2243   if (Rm == 0xD)
2244     Inst.addOperand(MCOperand::CreateReg(0));
2245   else if (Rm != 0xF) {
2246     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2247     return MCDisassembler::Fail;
2248   }
2249 
2250   // First input register
2251   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2252     return MCDisassembler::Fail;
2253 
2254   // Second input register
2255   switch (Inst.getOpcode()) {
2256     case ARM::VST1q8:
2257     case ARM::VST1q16:
2258     case ARM::VST1q32:
2259     case ARM::VST1q64:
2260     case ARM::VST1d8T:
2261     case ARM::VST1d16T:
2262     case ARM::VST1d32T:
2263     case ARM::VST1d64T:
2264     case ARM::VST1d8T_UPD:
2265     case ARM::VST1d16T_UPD:
2266     case ARM::VST1d32T_UPD:
2267     case ARM::VST1d64T_UPD:
2268     case ARM::VST1d8Q:
2269     case ARM::VST1d16Q:
2270     case ARM::VST1d32Q:
2271     case ARM::VST1d64Q:
2272     case ARM::VST1d8Q_UPD:
2273     case ARM::VST1d16Q_UPD:
2274     case ARM::VST1d32Q_UPD:
2275     case ARM::VST1d64Q_UPD:
2276     case ARM::VST2d8:
2277     case ARM::VST2d16:
2278     case ARM::VST2d32:
2279     case ARM::VST2d8_UPD:
2280     case ARM::VST2d16_UPD:
2281     case ARM::VST2d32_UPD:
2282     case ARM::VST2q8:
2283     case ARM::VST2q16:
2284     case ARM::VST2q32:
2285     case ARM::VST2q8_UPD:
2286     case ARM::VST2q16_UPD:
2287     case ARM::VST2q32_UPD:
2288     case ARM::VST3d8:
2289     case ARM::VST3d16:
2290     case ARM::VST3d32:
2291     case ARM::VST3d8_UPD:
2292     case ARM::VST3d16_UPD:
2293     case ARM::VST3d32_UPD:
2294     case ARM::VST4d8:
2295     case ARM::VST4d16:
2296     case ARM::VST4d32:
2297     case ARM::VST4d8_UPD:
2298     case ARM::VST4d16_UPD:
2299     case ARM::VST4d32_UPD:
2300       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
2301         return MCDisassembler::Fail;
2302       break;
2303     case ARM::VST2b8:
2304     case ARM::VST2b16:
2305     case ARM::VST2b32:
2306     case ARM::VST2b8_UPD:
2307     case ARM::VST2b16_UPD:
2308     case ARM::VST2b32_UPD:
2309     case ARM::VST3q8:
2310     case ARM::VST3q16:
2311     case ARM::VST3q32:
2312     case ARM::VST3q8_UPD:
2313     case ARM::VST3q16_UPD:
2314     case ARM::VST3q32_UPD:
2315     case ARM::VST4q8:
2316     case ARM::VST4q16:
2317     case ARM::VST4q32:
2318     case ARM::VST4q8_UPD:
2319     case ARM::VST4q16_UPD:
2320     case ARM::VST4q32_UPD:
2321       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2322         return MCDisassembler::Fail;
2323       break;
2324     default:
2325       break;
2326   }
2327 
2328   // Third input register
2329   switch (Inst.getOpcode()) {
2330     case ARM::VST1d8T:
2331     case ARM::VST1d16T:
2332     case ARM::VST1d32T:
2333     case ARM::VST1d64T:
2334     case ARM::VST1d8T_UPD:
2335     case ARM::VST1d16T_UPD:
2336     case ARM::VST1d32T_UPD:
2337     case ARM::VST1d64T_UPD:
2338     case ARM::VST1d8Q:
2339     case ARM::VST1d16Q:
2340     case ARM::VST1d32Q:
2341     case ARM::VST1d64Q:
2342     case ARM::VST1d8Q_UPD:
2343     case ARM::VST1d16Q_UPD:
2344     case ARM::VST1d32Q_UPD:
2345     case ARM::VST1d64Q_UPD:
2346     case ARM::VST2q8:
2347     case ARM::VST2q16:
2348     case ARM::VST2q32:
2349     case ARM::VST2q8_UPD:
2350     case ARM::VST2q16_UPD:
2351     case ARM::VST2q32_UPD:
2352     case ARM::VST3d8:
2353     case ARM::VST3d16:
2354     case ARM::VST3d32:
2355     case ARM::VST3d8_UPD:
2356     case ARM::VST3d16_UPD:
2357     case ARM::VST3d32_UPD:
2358     case ARM::VST4d8:
2359     case ARM::VST4d16:
2360     case ARM::VST4d32:
2361     case ARM::VST4d8_UPD:
2362     case ARM::VST4d16_UPD:
2363     case ARM::VST4d32_UPD:
2364       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2365         return MCDisassembler::Fail;
2366       break;
2367     case ARM::VST3q8:
2368     case ARM::VST3q16:
2369     case ARM::VST3q32:
2370     case ARM::VST3q8_UPD:
2371     case ARM::VST3q16_UPD:
2372     case ARM::VST3q32_UPD:
2373     case ARM::VST4q8:
2374     case ARM::VST4q16:
2375     case ARM::VST4q32:
2376     case ARM::VST4q8_UPD:
2377     case ARM::VST4q16_UPD:
2378     case ARM::VST4q32_UPD:
2379       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
2380         return MCDisassembler::Fail;
2381       break;
2382     default:
2383       break;
2384   }
2385 
2386   // Fourth input register
2387   switch (Inst.getOpcode()) {
2388     case ARM::VST1d8Q:
2389     case ARM::VST1d16Q:
2390     case ARM::VST1d32Q:
2391     case ARM::VST1d64Q:
2392     case ARM::VST1d8Q_UPD:
2393     case ARM::VST1d16Q_UPD:
2394     case ARM::VST1d32Q_UPD:
2395     case ARM::VST1d64Q_UPD:
2396     case ARM::VST2q8:
2397     case ARM::VST2q16:
2398     case ARM::VST2q32:
2399     case ARM::VST2q8_UPD:
2400     case ARM::VST2q16_UPD:
2401     case ARM::VST2q32_UPD:
2402     case ARM::VST4d8:
2403     case ARM::VST4d16:
2404     case ARM::VST4d32:
2405     case ARM::VST4d8_UPD:
2406     case ARM::VST4d16_UPD:
2407     case ARM::VST4d32_UPD:
2408       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
2409         return MCDisassembler::Fail;
2410       break;
2411     case ARM::VST4q8:
2412     case ARM::VST4q16:
2413     case ARM::VST4q32:
2414     case ARM::VST4q8_UPD:
2415     case ARM::VST4q16_UPD:
2416     case ARM::VST4q32_UPD:
2417       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
2418         return MCDisassembler::Fail;
2419       break;
2420     default:
2421       break;
2422   }
2423 
2424   return S;
2425 }
2426 
2427 static DecodeStatus DecodeVLD1DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2428                                     uint64_t Address, const void *Decoder) {
2429   DecodeStatus S = MCDisassembler::Success;
2430 
2431   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2432   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2433   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2434   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2435   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2436   unsigned size = fieldFromInstruction32(Insn, 6, 2);
2437   unsigned regs = fieldFromInstruction32(Insn, 5, 1) + 1;
2438 
2439   align *= (1 << size);
2440 
2441   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2442     return MCDisassembler::Fail;
2443   if (regs == 2) {
2444     if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
2445       return MCDisassembler::Fail;
2446   }
2447   if (Rm != 0xF) {
2448     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2449       return MCDisassembler::Fail;
2450   }
2451 
2452   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2453     return MCDisassembler::Fail;
2454   Inst.addOperand(MCOperand::CreateImm(align));
2455 
2456   if (Rm == 0xD)
2457     Inst.addOperand(MCOperand::CreateReg(0));
2458   else if (Rm != 0xF) {
2459     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2460       return MCDisassembler::Fail;
2461   }
2462 
2463   return S;
2464 }
2465 
2466 static DecodeStatus DecodeVLD2DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2467                                     uint64_t Address, const void *Decoder) {
2468   DecodeStatus S = MCDisassembler::Success;
2469 
2470   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2471   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2472   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2473   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2474   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2475   unsigned size = 1 << fieldFromInstruction32(Insn, 6, 2);
2476   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2477   align *= 2*size;
2478 
2479   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2480     return MCDisassembler::Fail;
2481   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
2482     return MCDisassembler::Fail;
2483   if (Rm != 0xF) {
2484     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2485       return MCDisassembler::Fail;
2486   }
2487 
2488   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2489     return MCDisassembler::Fail;
2490   Inst.addOperand(MCOperand::CreateImm(align));
2491 
2492   if (Rm == 0xD)
2493     Inst.addOperand(MCOperand::CreateReg(0));
2494   else if (Rm != 0xF) {
2495     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2496       return MCDisassembler::Fail;
2497   }
2498 
2499   return S;
2500 }
2501 
2502 static DecodeStatus DecodeVLD3DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2503                                     uint64_t Address, const void *Decoder) {
2504   DecodeStatus S = MCDisassembler::Success;
2505 
2506   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2507   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2508   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2509   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2510   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2511 
2512   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2513     return MCDisassembler::Fail;
2514   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
2515     return MCDisassembler::Fail;
2516   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
2517     return MCDisassembler::Fail;
2518   if (Rm != 0xF) {
2519     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2520       return MCDisassembler::Fail;
2521   }
2522 
2523   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2524     return MCDisassembler::Fail;
2525   Inst.addOperand(MCOperand::CreateImm(0));
2526 
2527   if (Rm == 0xD)
2528     Inst.addOperand(MCOperand::CreateReg(0));
2529   else if (Rm != 0xF) {
2530     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2531       return MCDisassembler::Fail;
2532   }
2533 
2534   return S;
2535 }
2536 
2537 static DecodeStatus DecodeVLD4DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2538                                     uint64_t Address, const void *Decoder) {
2539   DecodeStatus S = MCDisassembler::Success;
2540 
2541   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2542   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2543   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2544   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2545   unsigned size = fieldFromInstruction32(Insn, 6, 2);
2546   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2547   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2548 
2549   if (size == 0x3) {
2550     size = 4;
2551     align = 16;
2552   } else {
2553     if (size == 2) {
2554       size = 1 << size;
2555       align *= 8;
2556     } else {
2557       size = 1 << size;
2558       align *= 4*size;
2559     }
2560   }
2561 
2562   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2563     return MCDisassembler::Fail;
2564   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
2565     return MCDisassembler::Fail;
2566   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
2567     return MCDisassembler::Fail;
2568   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3*inc)%32, Address, Decoder)))
2569     return MCDisassembler::Fail;
2570   if (Rm != 0xF) {
2571     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2572       return MCDisassembler::Fail;
2573   }
2574 
2575   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2576     return MCDisassembler::Fail;
2577   Inst.addOperand(MCOperand::CreateImm(align));
2578 
2579   if (Rm == 0xD)
2580     Inst.addOperand(MCOperand::CreateReg(0));
2581   else if (Rm != 0xF) {
2582     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2583       return MCDisassembler::Fail;
2584   }
2585 
2586   return S;
2587 }
2588 
2589 static DecodeStatus
2590 DecodeNEONModImmInstruction(llvm::MCInst &Inst, unsigned Insn,
2591                             uint64_t Address, const void *Decoder) {
2592   DecodeStatus S = MCDisassembler::Success;
2593 
2594   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2595   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2596   unsigned imm = fieldFromInstruction32(Insn, 0, 4);
2597   imm |= fieldFromInstruction32(Insn, 16, 3) << 4;
2598   imm |= fieldFromInstruction32(Insn, 24, 1) << 7;
2599   imm |= fieldFromInstruction32(Insn, 8, 4) << 8;
2600   imm |= fieldFromInstruction32(Insn, 5, 1) << 12;
2601   unsigned Q = fieldFromInstruction32(Insn, 6, 1);
2602 
2603   if (Q) {
2604     if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2605     return MCDisassembler::Fail;
2606   } else {
2607     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2608     return MCDisassembler::Fail;
2609   }
2610 
2611   Inst.addOperand(MCOperand::CreateImm(imm));
2612 
2613   switch (Inst.getOpcode()) {
2614     case ARM::VORRiv4i16:
2615     case ARM::VORRiv2i32:
2616     case ARM::VBICiv4i16:
2617     case ARM::VBICiv2i32:
2618       if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2619         return MCDisassembler::Fail;
2620       break;
2621     case ARM::VORRiv8i16:
2622     case ARM::VORRiv4i32:
2623     case ARM::VBICiv8i16:
2624     case ARM::VBICiv4i32:
2625       if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2626         return MCDisassembler::Fail;
2627       break;
2628     default:
2629       break;
2630   }
2631 
2632   return S;
2633 }
2634 
2635 static DecodeStatus DecodeVSHLMaxInstruction(llvm::MCInst &Inst, unsigned Insn,
2636                                         uint64_t Address, const void *Decoder) {
2637   DecodeStatus S = MCDisassembler::Success;
2638 
2639   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2640   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2641   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2642   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
2643   unsigned size = fieldFromInstruction32(Insn, 18, 2);
2644 
2645   if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2646     return MCDisassembler::Fail;
2647   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
2648     return MCDisassembler::Fail;
2649   Inst.addOperand(MCOperand::CreateImm(8 << size));
2650 
2651   return S;
2652 }
2653 
2654 static DecodeStatus DecodeShiftRight8Imm(llvm::MCInst &Inst, unsigned Val,
2655                                uint64_t Address, const void *Decoder) {
2656   Inst.addOperand(MCOperand::CreateImm(8 - Val));
2657   return MCDisassembler::Success;
2658 }
2659 
2660 static DecodeStatus DecodeShiftRight16Imm(llvm::MCInst &Inst, unsigned Val,
2661                                uint64_t Address, const void *Decoder) {
2662   Inst.addOperand(MCOperand::CreateImm(16 - Val));
2663   return MCDisassembler::Success;
2664 }
2665 
2666 static DecodeStatus DecodeShiftRight32Imm(llvm::MCInst &Inst, unsigned Val,
2667                                uint64_t Address, const void *Decoder) {
2668   Inst.addOperand(MCOperand::CreateImm(32 - Val));
2669   return MCDisassembler::Success;
2670 }
2671 
2672 static DecodeStatus DecodeShiftRight64Imm(llvm::MCInst &Inst, unsigned Val,
2673                                uint64_t Address, const void *Decoder) {
2674   Inst.addOperand(MCOperand::CreateImm(64 - Val));
2675   return MCDisassembler::Success;
2676 }
2677 
2678 static DecodeStatus DecodeTBLInstruction(llvm::MCInst &Inst, unsigned Insn,
2679                                uint64_t Address, const void *Decoder) {
2680   DecodeStatus S = MCDisassembler::Success;
2681 
2682   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2683   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2684   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2685   Rn |= fieldFromInstruction32(Insn, 7, 1) << 4;
2686   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2687   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
2688   unsigned op = fieldFromInstruction32(Insn, 6, 1);
2689   unsigned length = fieldFromInstruction32(Insn, 8, 2) + 1;
2690 
2691   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2692     return MCDisassembler::Fail;
2693   if (op) {
2694     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2695     return MCDisassembler::Fail; // Writeback
2696   }
2697 
2698   for (unsigned i = 0; i < length; ++i) {
2699     if (!Check(S, DecodeDPRRegisterClass(Inst, (Rn+i)%32, Address, Decoder)))
2700     return MCDisassembler::Fail;
2701   }
2702 
2703   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
2704     return MCDisassembler::Fail;
2705 
2706   return S;
2707 }
2708 
2709 static DecodeStatus DecodeThumbAddSpecialReg(llvm::MCInst &Inst, uint16_t Insn,
2710                                      uint64_t Address, const void *Decoder) {
2711   DecodeStatus S = MCDisassembler::Success;
2712 
2713   unsigned dst = fieldFromInstruction16(Insn, 8, 3);
2714   unsigned imm = fieldFromInstruction16(Insn, 0, 8);
2715 
2716   if (!Check(S, DecodetGPRRegisterClass(Inst, dst, Address, Decoder)))
2717     return MCDisassembler::Fail;
2718 
2719   switch(Inst.getOpcode()) {
2720     default:
2721       return MCDisassembler::Fail;
2722     case ARM::tADR:
2723       break; // tADR does not explicitly represent the PC as an operand.
2724     case ARM::tADDrSPi:
2725       Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2726       break;
2727   }
2728 
2729   Inst.addOperand(MCOperand::CreateImm(imm));
2730   return S;
2731 }
2732 
2733 static DecodeStatus DecodeThumbBROperand(llvm::MCInst &Inst, unsigned Val,
2734                                  uint64_t Address, const void *Decoder) {
2735   Inst.addOperand(MCOperand::CreateImm(SignExtend32<12>(Val << 1)));
2736   return MCDisassembler::Success;
2737 }
2738 
2739 static DecodeStatus DecodeT2BROperand(llvm::MCInst &Inst, unsigned Val,
2740                                  uint64_t Address, const void *Decoder) {
2741   Inst.addOperand(MCOperand::CreateImm(SignExtend32<21>(Val)));
2742   return MCDisassembler::Success;
2743 }
2744 
2745 static DecodeStatus DecodeThumbCmpBROperand(llvm::MCInst &Inst, unsigned Val,
2746                                  uint64_t Address, const void *Decoder) {
2747   Inst.addOperand(MCOperand::CreateImm(SignExtend32<7>(Val << 1)));
2748   return MCDisassembler::Success;
2749 }
2750 
2751 static DecodeStatus DecodeThumbAddrModeRR(llvm::MCInst &Inst, unsigned Val,
2752                                  uint64_t Address, const void *Decoder) {
2753   DecodeStatus S = MCDisassembler::Success;
2754 
2755   unsigned Rn = fieldFromInstruction32(Val, 0, 3);
2756   unsigned Rm = fieldFromInstruction32(Val, 3, 3);
2757 
2758   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
2759     return MCDisassembler::Fail;
2760   if (!Check(S, DecodetGPRRegisterClass(Inst, Rm, Address, Decoder)))
2761     return MCDisassembler::Fail;
2762 
2763   return S;
2764 }
2765 
2766 static DecodeStatus DecodeThumbAddrModeIS(llvm::MCInst &Inst, unsigned Val,
2767                                   uint64_t Address, const void *Decoder) {
2768   DecodeStatus S = MCDisassembler::Success;
2769 
2770   unsigned Rn = fieldFromInstruction32(Val, 0, 3);
2771   unsigned imm = fieldFromInstruction32(Val, 3, 5);
2772 
2773   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
2774     return MCDisassembler::Fail;
2775   Inst.addOperand(MCOperand::CreateImm(imm));
2776 
2777   return S;
2778 }
2779 
2780 static DecodeStatus DecodeThumbAddrModePC(llvm::MCInst &Inst, unsigned Val,
2781                                   uint64_t Address, const void *Decoder) {
2782   unsigned imm = Val << 2;
2783 
2784   Inst.addOperand(MCOperand::CreateImm(imm));
2785   tryAddingPcLoadReferenceComment(Address, (Address & ~2u) + imm + 4, Decoder);
2786 
2787   return MCDisassembler::Success;
2788 }
2789 
2790 static DecodeStatus DecodeThumbAddrModeSP(llvm::MCInst &Inst, unsigned Val,
2791                                   uint64_t Address, const void *Decoder) {
2792   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2793   Inst.addOperand(MCOperand::CreateImm(Val));
2794 
2795   return MCDisassembler::Success;
2796 }
2797 
2798 static DecodeStatus DecodeT2AddrModeSOReg(llvm::MCInst &Inst, unsigned Val,
2799                                   uint64_t Address, const void *Decoder) {
2800   DecodeStatus S = MCDisassembler::Success;
2801 
2802   unsigned Rn = fieldFromInstruction32(Val, 6, 4);
2803   unsigned Rm = fieldFromInstruction32(Val, 2, 4);
2804   unsigned imm = fieldFromInstruction32(Val, 0, 2);
2805 
2806   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2807     return MCDisassembler::Fail;
2808   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
2809     return MCDisassembler::Fail;
2810   Inst.addOperand(MCOperand::CreateImm(imm));
2811 
2812   return S;
2813 }
2814 
2815 static DecodeStatus DecodeT2LoadShift(llvm::MCInst &Inst, unsigned Insn,
2816                               uint64_t Address, const void *Decoder) {
2817   DecodeStatus S = MCDisassembler::Success;
2818 
2819   switch (Inst.getOpcode()) {
2820     case ARM::t2PLDs:
2821     case ARM::t2PLDWs:
2822     case ARM::t2PLIs:
2823       break;
2824     default: {
2825       unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2826       if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
2827     return MCDisassembler::Fail;
2828     }
2829   }
2830 
2831   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2832   if (Rn == 0xF) {
2833     switch (Inst.getOpcode()) {
2834       case ARM::t2LDRBs:
2835         Inst.setOpcode(ARM::t2LDRBpci);
2836         break;
2837       case ARM::t2LDRHs:
2838         Inst.setOpcode(ARM::t2LDRHpci);
2839         break;
2840       case ARM::t2LDRSHs:
2841         Inst.setOpcode(ARM::t2LDRSHpci);
2842         break;
2843       case ARM::t2LDRSBs:
2844         Inst.setOpcode(ARM::t2LDRSBpci);
2845         break;
2846       case ARM::t2PLDs:
2847         Inst.setOpcode(ARM::t2PLDi12);
2848         Inst.addOperand(MCOperand::CreateReg(ARM::PC));
2849         break;
2850       default:
2851         return MCDisassembler::Fail;
2852     }
2853 
2854     int imm = fieldFromInstruction32(Insn, 0, 12);
2855     if (!fieldFromInstruction32(Insn, 23, 1)) imm *= -1;
2856     Inst.addOperand(MCOperand::CreateImm(imm));
2857 
2858     return S;
2859   }
2860 
2861   unsigned addrmode = fieldFromInstruction32(Insn, 4, 2);
2862   addrmode |= fieldFromInstruction32(Insn, 0, 4) << 2;
2863   addrmode |= fieldFromInstruction32(Insn, 16, 4) << 6;
2864   if (!Check(S, DecodeT2AddrModeSOReg(Inst, addrmode, Address, Decoder)))
2865     return MCDisassembler::Fail;
2866 
2867   return S;
2868 }
2869 
2870 static DecodeStatus DecodeT2Imm8S4(llvm::MCInst &Inst, unsigned Val,
2871                            uint64_t Address, const void *Decoder) {
2872   int imm = Val & 0xFF;
2873   if (!(Val & 0x100)) imm *= -1;
2874   Inst.addOperand(MCOperand::CreateImm(imm << 2));
2875 
2876   return MCDisassembler::Success;
2877 }
2878 
2879 static DecodeStatus DecodeT2AddrModeImm8s4(llvm::MCInst &Inst, unsigned Val,
2880                                    uint64_t Address, const void *Decoder) {
2881   DecodeStatus S = MCDisassembler::Success;
2882 
2883   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
2884   unsigned imm = fieldFromInstruction32(Val, 0, 9);
2885 
2886   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2887     return MCDisassembler::Fail;
2888   if (!Check(S, DecodeT2Imm8S4(Inst, imm, Address, Decoder)))
2889     return MCDisassembler::Fail;
2890 
2891   return S;
2892 }
2893 
2894 static DecodeStatus DecodeT2AddrModeImm0_1020s4(llvm::MCInst &Inst,unsigned Val,
2895                                    uint64_t Address, const void *Decoder) {
2896   DecodeStatus S = MCDisassembler::Success;
2897 
2898   unsigned Rn = fieldFromInstruction32(Val, 8, 4);
2899   unsigned imm = fieldFromInstruction32(Val, 0, 8);
2900 
2901   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
2902     return MCDisassembler::Fail;
2903 
2904   Inst.addOperand(MCOperand::CreateImm(imm));
2905 
2906   return S;
2907 }
2908 
2909 static DecodeStatus DecodeT2Imm8(llvm::MCInst &Inst, unsigned Val,
2910                          uint64_t Address, const void *Decoder) {
2911   int imm = Val & 0xFF;
2912   if (Val == 0)
2913     imm = INT32_MIN;
2914   else if (!(Val & 0x100))
2915     imm *= -1;
2916   Inst.addOperand(MCOperand::CreateImm(imm));
2917 
2918   return MCDisassembler::Success;
2919 }
2920 
2921 
2922 static DecodeStatus DecodeT2AddrModeImm8(llvm::MCInst &Inst, unsigned Val,
2923                                  uint64_t Address, const void *Decoder) {
2924   DecodeStatus S = MCDisassembler::Success;
2925 
2926   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
2927   unsigned imm = fieldFromInstruction32(Val, 0, 9);
2928 
2929   // Some instructions always use an additive offset.
2930   switch (Inst.getOpcode()) {
2931     case ARM::t2LDRT:
2932     case ARM::t2LDRBT:
2933     case ARM::t2LDRHT:
2934     case ARM::t2LDRSBT:
2935     case ARM::t2LDRSHT:
2936     case ARM::t2STRT:
2937     case ARM::t2STRBT:
2938     case ARM::t2STRHT:
2939       imm |= 0x100;
2940       break;
2941     default:
2942       break;
2943   }
2944 
2945   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2946     return MCDisassembler::Fail;
2947   if (!Check(S, DecodeT2Imm8(Inst, imm, Address, Decoder)))
2948     return MCDisassembler::Fail;
2949 
2950   return S;
2951 }
2952 
2953 static DecodeStatus DecodeT2LdStPre(llvm::MCInst &Inst, unsigned Insn,
2954                                     uint64_t Address, const void *Decoder) {
2955   DecodeStatus S = MCDisassembler::Success;
2956 
2957   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2958   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2959   unsigned addr = fieldFromInstruction32(Insn, 0, 8);
2960   addr |= fieldFromInstruction32(Insn, 9, 1) << 8;
2961   addr |= Rn << 9;
2962   unsigned load = fieldFromInstruction32(Insn, 20, 1);
2963 
2964   if (!load) {
2965     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2966       return MCDisassembler::Fail;
2967   }
2968 
2969   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
2970     return MCDisassembler::Fail;
2971 
2972   if (load) {
2973     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2974       return MCDisassembler::Fail;
2975   }
2976 
2977   if (!Check(S, DecodeT2AddrModeImm8(Inst, addr, Address, Decoder)))
2978     return MCDisassembler::Fail;
2979 
2980   return S;
2981 }
2982 
2983 static DecodeStatus DecodeT2AddrModeImm12(llvm::MCInst &Inst, unsigned Val,
2984                                   uint64_t Address, const void *Decoder) {
2985   DecodeStatus S = MCDisassembler::Success;
2986 
2987   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
2988   unsigned imm = fieldFromInstruction32(Val, 0, 12);
2989 
2990   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2991     return MCDisassembler::Fail;
2992   Inst.addOperand(MCOperand::CreateImm(imm));
2993 
2994   return S;
2995 }
2996 
2997 
2998 static DecodeStatus DecodeThumbAddSPImm(llvm::MCInst &Inst, uint16_t Insn,
2999                                 uint64_t Address, const void *Decoder) {
3000   unsigned imm = fieldFromInstruction16(Insn, 0, 7);
3001 
3002   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
3003   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
3004   Inst.addOperand(MCOperand::CreateImm(imm));
3005 
3006   return MCDisassembler::Success;
3007 }
3008 
3009 static DecodeStatus DecodeThumbAddSPReg(llvm::MCInst &Inst, uint16_t Insn,
3010                                 uint64_t Address, const void *Decoder) {
3011   DecodeStatus S = MCDisassembler::Success;
3012 
3013   if (Inst.getOpcode() == ARM::tADDrSP) {
3014     unsigned Rdm = fieldFromInstruction16(Insn, 0, 3);
3015     Rdm |= fieldFromInstruction16(Insn, 7, 1) << 3;
3016 
3017     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
3018     return MCDisassembler::Fail;
3019     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
3020     return MCDisassembler::Fail;
3021     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
3022   } else if (Inst.getOpcode() == ARM::tADDspr) {
3023     unsigned Rm = fieldFromInstruction16(Insn, 3, 4);
3024 
3025     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
3026     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
3027     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3028     return MCDisassembler::Fail;
3029   }
3030 
3031   return S;
3032 }
3033 
3034 static DecodeStatus DecodeThumbCPS(llvm::MCInst &Inst, uint16_t Insn,
3035                            uint64_t Address, const void *Decoder) {
3036   unsigned imod = fieldFromInstruction16(Insn, 4, 1) | 0x2;
3037   unsigned flags = fieldFromInstruction16(Insn, 0, 3);
3038 
3039   Inst.addOperand(MCOperand::CreateImm(imod));
3040   Inst.addOperand(MCOperand::CreateImm(flags));
3041 
3042   return MCDisassembler::Success;
3043 }
3044 
3045 static DecodeStatus DecodePostIdxReg(llvm::MCInst &Inst, unsigned Insn,
3046                              uint64_t Address, const void *Decoder) {
3047   DecodeStatus S = MCDisassembler::Success;
3048   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3049   unsigned add = fieldFromInstruction32(Insn, 4, 1);
3050 
3051   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3052     return MCDisassembler::Fail;
3053   Inst.addOperand(MCOperand::CreateImm(add));
3054 
3055   return S;
3056 }
3057 
3058 static DecodeStatus DecodeThumbBLXOffset(llvm::MCInst &Inst, unsigned Val,
3059                                  uint64_t Address, const void *Decoder) {
3060   if (!tryAddingSymbolicOperand(Address,
3061                                 (Address & ~2u) + SignExtend32<22>(Val << 1) + 4,
3062                                 true, 4, Inst, Decoder))
3063     Inst.addOperand(MCOperand::CreateImm(SignExtend32<22>(Val << 1)));
3064   return MCDisassembler::Success;
3065 }
3066 
3067 static DecodeStatus DecodeCoprocessor(llvm::MCInst &Inst, unsigned Val,
3068                               uint64_t Address, const void *Decoder) {
3069   if (Val == 0xA || Val == 0xB)
3070     return MCDisassembler::Fail;
3071 
3072   Inst.addOperand(MCOperand::CreateImm(Val));
3073   return MCDisassembler::Success;
3074 }
3075 
3076 static DecodeStatus
3077 DecodeThumbTableBranch(llvm::MCInst &Inst, unsigned Insn,
3078                        uint64_t Address, const void *Decoder) {
3079   DecodeStatus S = MCDisassembler::Success;
3080 
3081   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3082   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3083 
3084   if (Rn == ARM::SP) S = MCDisassembler::SoftFail;
3085   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3086     return MCDisassembler::Fail;
3087   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
3088     return MCDisassembler::Fail;
3089   return S;
3090 }
3091 
3092 static DecodeStatus
3093 DecodeThumb2BCCInstruction(llvm::MCInst &Inst, unsigned Insn,
3094                            uint64_t Address, const void *Decoder) {
3095   DecodeStatus S = MCDisassembler::Success;
3096 
3097   unsigned pred = fieldFromInstruction32(Insn, 22, 4);
3098   if (pred == 0xE || pred == 0xF) {
3099     unsigned opc = fieldFromInstruction32(Insn, 4, 28);
3100     switch (opc) {
3101       default:
3102         return MCDisassembler::Fail;
3103       case 0xf3bf8f4:
3104         Inst.setOpcode(ARM::t2DSB);
3105         break;
3106       case 0xf3bf8f5:
3107         Inst.setOpcode(ARM::t2DMB);
3108         break;
3109       case 0xf3bf8f6:
3110         Inst.setOpcode(ARM::t2ISB);
3111         break;
3112     }
3113 
3114     unsigned imm = fieldFromInstruction32(Insn, 0, 4);
3115     return DecodeMemBarrierOption(Inst, imm, Address, Decoder);
3116   }
3117 
3118   unsigned brtarget = fieldFromInstruction32(Insn, 0, 11) << 1;
3119   brtarget |= fieldFromInstruction32(Insn, 11, 1) << 19;
3120   brtarget |= fieldFromInstruction32(Insn, 13, 1) << 18;
3121   brtarget |= fieldFromInstruction32(Insn, 16, 6) << 12;
3122   brtarget |= fieldFromInstruction32(Insn, 26, 1) << 20;
3123 
3124   if (!Check(S, DecodeT2BROperand(Inst, brtarget, Address, Decoder)))
3125     return MCDisassembler::Fail;
3126   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3127     return MCDisassembler::Fail;
3128 
3129   return S;
3130 }
3131 
3132 // Decode a shifted immediate operand.  These basically consist
3133 // of an 8-bit value, and a 4-bit directive that specifies either
3134 // a splat operation or a rotation.
3135 static DecodeStatus DecodeT2SOImm(llvm::MCInst &Inst, unsigned Val,
3136                           uint64_t Address, const void *Decoder) {
3137   unsigned ctrl = fieldFromInstruction32(Val, 10, 2);
3138   if (ctrl == 0) {
3139     unsigned byte = fieldFromInstruction32(Val, 8, 2);
3140     unsigned imm = fieldFromInstruction32(Val, 0, 8);
3141     switch (byte) {
3142       case 0:
3143         Inst.addOperand(MCOperand::CreateImm(imm));
3144         break;
3145       case 1:
3146         Inst.addOperand(MCOperand::CreateImm((imm << 16) | imm));
3147         break;
3148       case 2:
3149         Inst.addOperand(MCOperand::CreateImm((imm << 24) | (imm << 8)));
3150         break;
3151       case 3:
3152         Inst.addOperand(MCOperand::CreateImm((imm << 24) | (imm << 16) |
3153                                              (imm << 8)  |  imm));
3154         break;
3155     }
3156   } else {
3157     unsigned unrot = fieldFromInstruction32(Val, 0, 7) | 0x80;
3158     unsigned rot = fieldFromInstruction32(Val, 7, 5);
3159     unsigned imm = (unrot >> rot) | (unrot << ((32-rot)&31));
3160     Inst.addOperand(MCOperand::CreateImm(imm));
3161   }
3162 
3163   return MCDisassembler::Success;
3164 }
3165 
3166 static DecodeStatus
3167 DecodeThumbBCCTargetOperand(llvm::MCInst &Inst, unsigned Val,
3168                             uint64_t Address, const void *Decoder){
3169   Inst.addOperand(MCOperand::CreateImm(Val << 1));
3170   return MCDisassembler::Success;
3171 }
3172 
3173 static DecodeStatus DecodeThumbBLTargetOperand(llvm::MCInst &Inst, unsigned Val,
3174                                        uint64_t Address, const void *Decoder){
3175   Inst.addOperand(MCOperand::CreateImm(SignExtend32<22>(Val << 1)));
3176   return MCDisassembler::Success;
3177 }
3178 
3179 static DecodeStatus DecodeMemBarrierOption(llvm::MCInst &Inst, unsigned Val,
3180                                    uint64_t Address, const void *Decoder) {
3181   switch (Val) {
3182   default:
3183     return MCDisassembler::Fail;
3184   case 0xF: // SY
3185   case 0xE: // ST
3186   case 0xB: // ISH
3187   case 0xA: // ISHST
3188   case 0x7: // NSH
3189   case 0x6: // NSHST
3190   case 0x3: // OSH
3191   case 0x2: // OSHST
3192     break;
3193   }
3194 
3195   Inst.addOperand(MCOperand::CreateImm(Val));
3196   return MCDisassembler::Success;
3197 }
3198 
3199 static DecodeStatus DecodeMSRMask(llvm::MCInst &Inst, unsigned Val,
3200                           uint64_t Address, const void *Decoder) {
3201   if (!Val) return MCDisassembler::Fail;
3202   Inst.addOperand(MCOperand::CreateImm(Val));
3203   return MCDisassembler::Success;
3204 }
3205 
3206 static DecodeStatus DecodeDoubleRegLoad(llvm::MCInst &Inst, unsigned Insn,
3207                                         uint64_t Address, const void *Decoder) {
3208   DecodeStatus S = MCDisassembler::Success;
3209 
3210   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3211   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3212   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3213 
3214   if ((Rt & 1) || Rt == 0xE || Rn == 0xF) return MCDisassembler::Fail;
3215 
3216   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3217     return MCDisassembler::Fail;
3218   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
3219     return MCDisassembler::Fail;
3220   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3221     return MCDisassembler::Fail;
3222   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3223     return MCDisassembler::Fail;
3224 
3225   return S;
3226 }
3227 
3228 
3229 static DecodeStatus DecodeDoubleRegStore(llvm::MCInst &Inst, unsigned Insn,
3230                                          uint64_t Address, const void *Decoder){
3231   DecodeStatus S = MCDisassembler::Success;
3232 
3233   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3234   unsigned Rt = fieldFromInstruction32(Insn, 0, 4);
3235   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3236   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3237 
3238   if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
3239     return MCDisassembler::Fail;
3240 
3241   if ((Rt & 1) || Rt == 0xE || Rn == 0xF) return MCDisassembler::Fail;
3242   if (Rd == Rn || Rd == Rt || Rd == Rt+1) return MCDisassembler::Fail;
3243 
3244   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3245     return MCDisassembler::Fail;
3246   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
3247     return MCDisassembler::Fail;
3248   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3249     return MCDisassembler::Fail;
3250   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3251     return MCDisassembler::Fail;
3252 
3253   return S;
3254 }
3255 
3256 static DecodeStatus DecodeLDRPreImm(llvm::MCInst &Inst, unsigned Insn,
3257                             uint64_t Address, const void *Decoder) {
3258   DecodeStatus S = MCDisassembler::Success;
3259 
3260   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3261   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3262   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3263   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3264   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3265   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3266 
3267   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3268 
3269   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3270     return MCDisassembler::Fail;
3271   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3272     return MCDisassembler::Fail;
3273   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
3274     return MCDisassembler::Fail;
3275   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3276     return MCDisassembler::Fail;
3277 
3278   return S;
3279 }
3280 
3281 static DecodeStatus DecodeLDRPreReg(llvm::MCInst &Inst, unsigned Insn,
3282                             uint64_t Address, const void *Decoder) {
3283   DecodeStatus S = MCDisassembler::Success;
3284 
3285   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3286   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3287   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3288   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3289   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3290   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3291   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3292 
3293   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3294   if (Rm == 0xF) S = MCDisassembler::SoftFail;
3295 
3296   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3297     return MCDisassembler::Fail;
3298   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3299     return MCDisassembler::Fail;
3300   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
3301     return MCDisassembler::Fail;
3302   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3303     return MCDisassembler::Fail;
3304 
3305   return S;
3306 }
3307 
3308 
3309 static DecodeStatus DecodeSTRPreImm(llvm::MCInst &Inst, unsigned Insn,
3310                             uint64_t Address, const void *Decoder) {
3311   DecodeStatus S = MCDisassembler::Success;
3312 
3313   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3314   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3315   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3316   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3317   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3318   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3319 
3320   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3321 
3322   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3323     return MCDisassembler::Fail;
3324   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3325     return MCDisassembler::Fail;
3326   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
3327     return MCDisassembler::Fail;
3328   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3329     return MCDisassembler::Fail;
3330 
3331   return S;
3332 }
3333 
3334 static DecodeStatus DecodeSTRPreReg(llvm::MCInst &Inst, unsigned Insn,
3335                             uint64_t Address, const void *Decoder) {
3336   DecodeStatus S = MCDisassembler::Success;
3337 
3338   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3339   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3340   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3341   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3342   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3343   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3344 
3345   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3346 
3347   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3348     return MCDisassembler::Fail;
3349   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3350     return MCDisassembler::Fail;
3351   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
3352     return MCDisassembler::Fail;
3353   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3354     return MCDisassembler::Fail;
3355 
3356   return S;
3357 }
3358 
3359 static DecodeStatus DecodeVLD1LN(llvm::MCInst &Inst, unsigned Insn,
3360                          uint64_t Address, const void *Decoder) {
3361   DecodeStatus S = MCDisassembler::Success;
3362 
3363   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3364   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3365   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3366   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3367   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3368 
3369   unsigned align = 0;
3370   unsigned index = 0;
3371   switch (size) {
3372     default:
3373       return MCDisassembler::Fail;
3374     case 0:
3375       if (fieldFromInstruction32(Insn, 4, 1))
3376         return MCDisassembler::Fail; // UNDEFINED
3377       index = fieldFromInstruction32(Insn, 5, 3);
3378       break;
3379     case 1:
3380       if (fieldFromInstruction32(Insn, 5, 1))
3381         return MCDisassembler::Fail; // UNDEFINED
3382       index = fieldFromInstruction32(Insn, 6, 2);
3383       if (fieldFromInstruction32(Insn, 4, 1))
3384         align = 2;
3385       break;
3386     case 2:
3387       if (fieldFromInstruction32(Insn, 6, 1))
3388         return MCDisassembler::Fail; // UNDEFINED
3389       index = fieldFromInstruction32(Insn, 7, 1);
3390       if (fieldFromInstruction32(Insn, 4, 2) != 0)
3391         align = 4;
3392   }
3393 
3394   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3395     return MCDisassembler::Fail;
3396   if (Rm != 0xF) { // Writeback
3397     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3398       return MCDisassembler::Fail;
3399   }
3400   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3401     return MCDisassembler::Fail;
3402   Inst.addOperand(MCOperand::CreateImm(align));
3403   if (Rm != 0xF) {
3404     if (Rm != 0xD) {
3405       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3406         return MCDisassembler::Fail;
3407     } else
3408       Inst.addOperand(MCOperand::CreateReg(0));
3409   }
3410 
3411   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3412     return MCDisassembler::Fail;
3413   Inst.addOperand(MCOperand::CreateImm(index));
3414 
3415   return S;
3416 }
3417 
3418 static DecodeStatus DecodeVST1LN(llvm::MCInst &Inst, unsigned Insn,
3419                          uint64_t Address, const void *Decoder) {
3420   DecodeStatus S = MCDisassembler::Success;
3421 
3422   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3423   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3424   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3425   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3426   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3427 
3428   unsigned align = 0;
3429   unsigned index = 0;
3430   switch (size) {
3431     default:
3432       return MCDisassembler::Fail;
3433     case 0:
3434       if (fieldFromInstruction32(Insn, 4, 1))
3435         return MCDisassembler::Fail; // UNDEFINED
3436       index = fieldFromInstruction32(Insn, 5, 3);
3437       break;
3438     case 1:
3439       if (fieldFromInstruction32(Insn, 5, 1))
3440         return MCDisassembler::Fail; // UNDEFINED
3441       index = fieldFromInstruction32(Insn, 6, 2);
3442       if (fieldFromInstruction32(Insn, 4, 1))
3443         align = 2;
3444       break;
3445     case 2:
3446       if (fieldFromInstruction32(Insn, 6, 1))
3447         return MCDisassembler::Fail; // UNDEFINED
3448       index = fieldFromInstruction32(Insn, 7, 1);
3449       if (fieldFromInstruction32(Insn, 4, 2) != 0)
3450         align = 4;
3451   }
3452 
3453   if (Rm != 0xF) { // Writeback
3454     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3455     return MCDisassembler::Fail;
3456   }
3457   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3458     return MCDisassembler::Fail;
3459   Inst.addOperand(MCOperand::CreateImm(align));
3460   if (Rm != 0xF) {
3461     if (Rm != 0xD) {
3462       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3463     return MCDisassembler::Fail;
3464     } else
3465       Inst.addOperand(MCOperand::CreateReg(0));
3466   }
3467 
3468   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3469     return MCDisassembler::Fail;
3470   Inst.addOperand(MCOperand::CreateImm(index));
3471 
3472   return S;
3473 }
3474 
3475 
3476 static DecodeStatus DecodeVLD2LN(llvm::MCInst &Inst, unsigned Insn,
3477                          uint64_t Address, const void *Decoder) {
3478   DecodeStatus S = MCDisassembler::Success;
3479 
3480   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3481   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3482   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3483   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3484   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3485 
3486   unsigned align = 0;
3487   unsigned index = 0;
3488   unsigned inc = 1;
3489   switch (size) {
3490     default:
3491       return MCDisassembler::Fail;
3492     case 0:
3493       index = fieldFromInstruction32(Insn, 5, 3);
3494       if (fieldFromInstruction32(Insn, 4, 1))
3495         align = 2;
3496       break;
3497     case 1:
3498       index = fieldFromInstruction32(Insn, 6, 2);
3499       if (fieldFromInstruction32(Insn, 4, 1))
3500         align = 4;
3501       if (fieldFromInstruction32(Insn, 5, 1))
3502         inc = 2;
3503       break;
3504     case 2:
3505       if (fieldFromInstruction32(Insn, 5, 1))
3506         return MCDisassembler::Fail; // UNDEFINED
3507       index = fieldFromInstruction32(Insn, 7, 1);
3508       if (fieldFromInstruction32(Insn, 4, 1) != 0)
3509         align = 8;
3510       if (fieldFromInstruction32(Insn, 6, 1))
3511         inc = 2;
3512       break;
3513   }
3514 
3515   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3516     return MCDisassembler::Fail;
3517   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3518     return MCDisassembler::Fail;
3519   if (Rm != 0xF) { // Writeback
3520     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3521       return MCDisassembler::Fail;
3522   }
3523   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3524     return MCDisassembler::Fail;
3525   Inst.addOperand(MCOperand::CreateImm(align));
3526   if (Rm != 0xF) {
3527     if (Rm != 0xD) {
3528       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3529         return MCDisassembler::Fail;
3530     } else
3531       Inst.addOperand(MCOperand::CreateReg(0));
3532   }
3533 
3534   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3535     return MCDisassembler::Fail;
3536   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3537     return MCDisassembler::Fail;
3538   Inst.addOperand(MCOperand::CreateImm(index));
3539 
3540   return S;
3541 }
3542 
3543 static DecodeStatus DecodeVST2LN(llvm::MCInst &Inst, unsigned Insn,
3544                          uint64_t Address, const void *Decoder) {
3545   DecodeStatus S = MCDisassembler::Success;
3546 
3547   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3548   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3549   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3550   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3551   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3552 
3553   unsigned align = 0;
3554   unsigned index = 0;
3555   unsigned inc = 1;
3556   switch (size) {
3557     default:
3558       return MCDisassembler::Fail;
3559     case 0:
3560       index = fieldFromInstruction32(Insn, 5, 3);
3561       if (fieldFromInstruction32(Insn, 4, 1))
3562         align = 2;
3563       break;
3564     case 1:
3565       index = fieldFromInstruction32(Insn, 6, 2);
3566       if (fieldFromInstruction32(Insn, 4, 1))
3567         align = 4;
3568       if (fieldFromInstruction32(Insn, 5, 1))
3569         inc = 2;
3570       break;
3571     case 2:
3572       if (fieldFromInstruction32(Insn, 5, 1))
3573         return MCDisassembler::Fail; // UNDEFINED
3574       index = fieldFromInstruction32(Insn, 7, 1);
3575       if (fieldFromInstruction32(Insn, 4, 1) != 0)
3576         align = 8;
3577       if (fieldFromInstruction32(Insn, 6, 1))
3578         inc = 2;
3579       break;
3580   }
3581 
3582   if (Rm != 0xF) { // Writeback
3583     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3584       return MCDisassembler::Fail;
3585   }
3586   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3587     return MCDisassembler::Fail;
3588   Inst.addOperand(MCOperand::CreateImm(align));
3589   if (Rm != 0xF) {
3590     if (Rm != 0xD) {
3591       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3592         return MCDisassembler::Fail;
3593     } else
3594       Inst.addOperand(MCOperand::CreateReg(0));
3595   }
3596 
3597   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3598     return MCDisassembler::Fail;
3599   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3600     return MCDisassembler::Fail;
3601   Inst.addOperand(MCOperand::CreateImm(index));
3602 
3603   return S;
3604 }
3605 
3606 
3607 static DecodeStatus DecodeVLD3LN(llvm::MCInst &Inst, unsigned Insn,
3608                          uint64_t Address, const void *Decoder) {
3609   DecodeStatus S = MCDisassembler::Success;
3610 
3611   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3612   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3613   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3614   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3615   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3616 
3617   unsigned align = 0;
3618   unsigned index = 0;
3619   unsigned inc = 1;
3620   switch (size) {
3621     default:
3622       return MCDisassembler::Fail;
3623     case 0:
3624       if (fieldFromInstruction32(Insn, 4, 1))
3625         return MCDisassembler::Fail; // UNDEFINED
3626       index = fieldFromInstruction32(Insn, 5, 3);
3627       break;
3628     case 1:
3629       if (fieldFromInstruction32(Insn, 4, 1))
3630         return MCDisassembler::Fail; // UNDEFINED
3631       index = fieldFromInstruction32(Insn, 6, 2);
3632       if (fieldFromInstruction32(Insn, 5, 1))
3633         inc = 2;
3634       break;
3635     case 2:
3636       if (fieldFromInstruction32(Insn, 4, 2))
3637         return MCDisassembler::Fail; // UNDEFINED
3638       index = fieldFromInstruction32(Insn, 7, 1);
3639       if (fieldFromInstruction32(Insn, 6, 1))
3640         inc = 2;
3641       break;
3642   }
3643 
3644   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3645     return MCDisassembler::Fail;
3646   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3647     return MCDisassembler::Fail;
3648   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3649     return MCDisassembler::Fail;
3650 
3651   if (Rm != 0xF) { // Writeback
3652     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3653     return MCDisassembler::Fail;
3654   }
3655   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3656     return MCDisassembler::Fail;
3657   Inst.addOperand(MCOperand::CreateImm(align));
3658   if (Rm != 0xF) {
3659     if (Rm != 0xD) {
3660       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3661     return MCDisassembler::Fail;
3662     } else
3663       Inst.addOperand(MCOperand::CreateReg(0));
3664   }
3665 
3666   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3667     return MCDisassembler::Fail;
3668   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3669     return MCDisassembler::Fail;
3670   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3671     return MCDisassembler::Fail;
3672   Inst.addOperand(MCOperand::CreateImm(index));
3673 
3674   return S;
3675 }
3676 
3677 static DecodeStatus DecodeVST3LN(llvm::MCInst &Inst, unsigned Insn,
3678                          uint64_t Address, const void *Decoder) {
3679   DecodeStatus S = MCDisassembler::Success;
3680 
3681   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3682   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3683   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3684   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3685   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3686 
3687   unsigned align = 0;
3688   unsigned index = 0;
3689   unsigned inc = 1;
3690   switch (size) {
3691     default:
3692       return MCDisassembler::Fail;
3693     case 0:
3694       if (fieldFromInstruction32(Insn, 4, 1))
3695         return MCDisassembler::Fail; // UNDEFINED
3696       index = fieldFromInstruction32(Insn, 5, 3);
3697       break;
3698     case 1:
3699       if (fieldFromInstruction32(Insn, 4, 1))
3700         return MCDisassembler::Fail; // UNDEFINED
3701       index = fieldFromInstruction32(Insn, 6, 2);
3702       if (fieldFromInstruction32(Insn, 5, 1))
3703         inc = 2;
3704       break;
3705     case 2:
3706       if (fieldFromInstruction32(Insn, 4, 2))
3707         return MCDisassembler::Fail; // UNDEFINED
3708       index = fieldFromInstruction32(Insn, 7, 1);
3709       if (fieldFromInstruction32(Insn, 6, 1))
3710         inc = 2;
3711       break;
3712   }
3713 
3714   if (Rm != 0xF) { // Writeback
3715     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3716     return MCDisassembler::Fail;
3717   }
3718   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3719     return MCDisassembler::Fail;
3720   Inst.addOperand(MCOperand::CreateImm(align));
3721   if (Rm != 0xF) {
3722     if (Rm != 0xD) {
3723       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3724     return MCDisassembler::Fail;
3725     } else
3726       Inst.addOperand(MCOperand::CreateReg(0));
3727   }
3728 
3729   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3730     return MCDisassembler::Fail;
3731   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3732     return MCDisassembler::Fail;
3733   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3734     return MCDisassembler::Fail;
3735   Inst.addOperand(MCOperand::CreateImm(index));
3736 
3737   return S;
3738 }
3739 
3740 
3741 static DecodeStatus DecodeVLD4LN(llvm::MCInst &Inst, unsigned Insn,
3742                          uint64_t Address, const void *Decoder) {
3743   DecodeStatus S = MCDisassembler::Success;
3744 
3745   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3746   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3747   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3748   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3749   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3750 
3751   unsigned align = 0;
3752   unsigned index = 0;
3753   unsigned inc = 1;
3754   switch (size) {
3755     default:
3756       return MCDisassembler::Fail;
3757     case 0:
3758       if (fieldFromInstruction32(Insn, 4, 1))
3759         align = 4;
3760       index = fieldFromInstruction32(Insn, 5, 3);
3761       break;
3762     case 1:
3763       if (fieldFromInstruction32(Insn, 4, 1))
3764         align = 8;
3765       index = fieldFromInstruction32(Insn, 6, 2);
3766       if (fieldFromInstruction32(Insn, 5, 1))
3767         inc = 2;
3768       break;
3769     case 2:
3770       if (fieldFromInstruction32(Insn, 4, 2))
3771         align = 4 << fieldFromInstruction32(Insn, 4, 2);
3772       index = fieldFromInstruction32(Insn, 7, 1);
3773       if (fieldFromInstruction32(Insn, 6, 1))
3774         inc = 2;
3775       break;
3776   }
3777 
3778   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3779     return MCDisassembler::Fail;
3780   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3781     return MCDisassembler::Fail;
3782   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3783     return MCDisassembler::Fail;
3784   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
3785     return MCDisassembler::Fail;
3786 
3787   if (Rm != 0xF) { // Writeback
3788     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3789       return MCDisassembler::Fail;
3790   }
3791   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3792     return MCDisassembler::Fail;
3793   Inst.addOperand(MCOperand::CreateImm(align));
3794   if (Rm != 0xF) {
3795     if (Rm != 0xD) {
3796       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3797         return MCDisassembler::Fail;
3798     } else
3799       Inst.addOperand(MCOperand::CreateReg(0));
3800   }
3801 
3802   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3803     return MCDisassembler::Fail;
3804   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3805     return MCDisassembler::Fail;
3806   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3807     return MCDisassembler::Fail;
3808   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
3809     return MCDisassembler::Fail;
3810   Inst.addOperand(MCOperand::CreateImm(index));
3811 
3812   return S;
3813 }
3814 
3815 static DecodeStatus DecodeVST4LN(llvm::MCInst &Inst, unsigned Insn,
3816                          uint64_t Address, const void *Decoder) {
3817   DecodeStatus S = MCDisassembler::Success;
3818 
3819   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3820   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3821   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3822   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3823   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3824 
3825   unsigned align = 0;
3826   unsigned index = 0;
3827   unsigned inc = 1;
3828   switch (size) {
3829     default:
3830       return MCDisassembler::Fail;
3831     case 0:
3832       if (fieldFromInstruction32(Insn, 4, 1))
3833         align = 4;
3834       index = fieldFromInstruction32(Insn, 5, 3);
3835       break;
3836     case 1:
3837       if (fieldFromInstruction32(Insn, 4, 1))
3838         align = 8;
3839       index = fieldFromInstruction32(Insn, 6, 2);
3840       if (fieldFromInstruction32(Insn, 5, 1))
3841         inc = 2;
3842       break;
3843     case 2:
3844       if (fieldFromInstruction32(Insn, 4, 2))
3845         align = 4 << fieldFromInstruction32(Insn, 4, 2);
3846       index = fieldFromInstruction32(Insn, 7, 1);
3847       if (fieldFromInstruction32(Insn, 6, 1))
3848         inc = 2;
3849       break;
3850   }
3851 
3852   if (Rm != 0xF) { // Writeback
3853     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3854     return MCDisassembler::Fail;
3855   }
3856   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3857     return MCDisassembler::Fail;
3858   Inst.addOperand(MCOperand::CreateImm(align));
3859   if (Rm != 0xF) {
3860     if (Rm != 0xD) {
3861       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3862     return MCDisassembler::Fail;
3863     } else
3864       Inst.addOperand(MCOperand::CreateReg(0));
3865   }
3866 
3867   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3868     return MCDisassembler::Fail;
3869   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3870     return MCDisassembler::Fail;
3871   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3872     return MCDisassembler::Fail;
3873   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
3874     return MCDisassembler::Fail;
3875   Inst.addOperand(MCOperand::CreateImm(index));
3876 
3877   return S;
3878 }
3879 
3880 static DecodeStatus DecodeVMOVSRR(llvm::MCInst &Inst, unsigned Insn,
3881                                   uint64_t Address, const void *Decoder) {
3882   DecodeStatus S = MCDisassembler::Success;
3883   unsigned Rt  = fieldFromInstruction32(Insn, 12, 4);
3884   unsigned Rt2 = fieldFromInstruction32(Insn, 16, 4);
3885   unsigned Rm  = fieldFromInstruction32(Insn,  0, 4);
3886   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3887   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
3888 
3889   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
3890     S = MCDisassembler::SoftFail;
3891 
3892   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
3893     return MCDisassembler::Fail;
3894   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
3895     return MCDisassembler::Fail;
3896   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
3897     return MCDisassembler::Fail;
3898   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
3899     return MCDisassembler::Fail;
3900   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3901     return MCDisassembler::Fail;
3902 
3903   return S;
3904 }
3905 
3906 static DecodeStatus DecodeVMOVRRS(llvm::MCInst &Inst, unsigned Insn,
3907                                   uint64_t Address, const void *Decoder) {
3908   DecodeStatus S = MCDisassembler::Success;
3909   unsigned Rt  = fieldFromInstruction32(Insn, 12, 4);
3910   unsigned Rt2 = fieldFromInstruction32(Insn, 16, 4);
3911   unsigned Rm  = fieldFromInstruction32(Insn,  0, 4);
3912   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3913   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
3914 
3915   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
3916     S = MCDisassembler::SoftFail;
3917 
3918   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
3919     return MCDisassembler::Fail;
3920   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
3921     return MCDisassembler::Fail;
3922   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
3923     return MCDisassembler::Fail;
3924   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
3925     return MCDisassembler::Fail;
3926   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3927     return MCDisassembler::Fail;
3928 
3929   return S;
3930 }
3931 
3932 static DecodeStatus DecodeIT(llvm::MCInst &Inst, unsigned Insn,
3933                              uint64_t Address, const void *Decoder) {
3934   DecodeStatus S = MCDisassembler::Success;
3935   unsigned pred = fieldFromInstruction16(Insn, 4, 4);
3936   // The InstPrinter needs to have the low bit of the predicate in
3937   // the mask operand to be able to print it properly.
3938   unsigned mask = fieldFromInstruction16(Insn, 0, 5);
3939 
3940   if (pred == 0xF) {
3941     pred = 0xE;
3942     S = MCDisassembler::SoftFail;
3943   }
3944 
3945   if ((mask & 0xF) == 0) {
3946     // Preserve the high bit of the mask, which is the low bit of
3947     // the predicate.
3948     mask &= 0x10;
3949     mask |= 0x8;
3950     S = MCDisassembler::SoftFail;
3951   }
3952 
3953   Inst.addOperand(MCOperand::CreateImm(pred));
3954   Inst.addOperand(MCOperand::CreateImm(mask));
3955   return S;
3956 }
3957 
3958 static DecodeStatus
3959 DecodeT2LDRDPreInstruction(llvm::MCInst &Inst, unsigned Insn,
3960                            uint64_t Address, const void *Decoder) {
3961   DecodeStatus S = MCDisassembler::Success;
3962 
3963   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3964   unsigned Rt2 = fieldFromInstruction32(Insn, 8, 4);
3965   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3966   unsigned addr = fieldFromInstruction32(Insn, 0, 8);
3967   unsigned W = fieldFromInstruction32(Insn, 21, 1);
3968   unsigned U = fieldFromInstruction32(Insn, 23, 1);
3969   unsigned P = fieldFromInstruction32(Insn, 24, 1);
3970   bool writeback = (W == 1) | (P == 0);
3971 
3972   addr |= (U << 8) | (Rn << 9);
3973 
3974   if (writeback && (Rn == Rt || Rn == Rt2))
3975     Check(S, MCDisassembler::SoftFail);
3976   if (Rt == Rt2)
3977     Check(S, MCDisassembler::SoftFail);
3978 
3979   // Rt
3980   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
3981     return MCDisassembler::Fail;
3982   // Rt2
3983   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
3984     return MCDisassembler::Fail;
3985   // Writeback operand
3986   if (!Check(S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
3987     return MCDisassembler::Fail;
3988   // addr
3989   if (!Check(S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
3990     return MCDisassembler::Fail;
3991 
3992   return S;
3993 }
3994 
3995 static DecodeStatus
3996 DecodeT2STRDPreInstruction(llvm::MCInst &Inst, unsigned Insn,
3997                            uint64_t Address, const void *Decoder) {
3998   DecodeStatus S = MCDisassembler::Success;
3999 
4000   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
4001   unsigned Rt2 = fieldFromInstruction32(Insn, 8, 4);
4002   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
4003   unsigned addr = fieldFromInstruction32(Insn, 0, 8);
4004   unsigned W = fieldFromInstruction32(Insn, 21, 1);
4005   unsigned U = fieldFromInstruction32(Insn, 23, 1);
4006   unsigned P = fieldFromInstruction32(Insn, 24, 1);
4007   bool writeback = (W == 1) | (P == 0);
4008 
4009   addr |= (U << 8) | (Rn << 9);
4010 
4011   if (writeback && (Rn == Rt || Rn == Rt2))
4012     Check(S, MCDisassembler::SoftFail);
4013 
4014   // Writeback operand
4015   if (!Check(S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
4016     return MCDisassembler::Fail;
4017   // Rt
4018   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
4019     return MCDisassembler::Fail;
4020   // Rt2
4021   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
4022     return MCDisassembler::Fail;
4023   // addr
4024   if (!Check(S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
4025     return MCDisassembler::Fail;
4026 
4027   return S;
4028 }
4029 
4030 static DecodeStatus DecodeT2Adr(llvm::MCInst &Inst, uint32_t Insn,
4031                                 uint64_t Address, const void *Decoder) {
4032   unsigned sign1 = fieldFromInstruction32(Insn, 21, 1);
4033   unsigned sign2 = fieldFromInstruction32(Insn, 23, 1);
4034   if (sign1 != sign2) return MCDisassembler::Fail;
4035 
4036   unsigned Val = fieldFromInstruction32(Insn, 0, 8);
4037   Val |= fieldFromInstruction32(Insn, 12, 3) << 8;
4038   Val |= fieldFromInstruction32(Insn, 26, 1) << 11;
4039   Val |= sign1 << 12;
4040   Inst.addOperand(MCOperand::CreateImm(SignExtend32<13>(Val)));
4041 
4042   return MCDisassembler::Success;
4043 }
4044 
4045 static DecodeStatus DecodeT2ShifterImmOperand(llvm::MCInst &Inst, uint32_t Val,
4046                                               uint64_t Address,
4047                                               const void *Decoder) {
4048   DecodeStatus S = MCDisassembler::Success;
4049 
4050   // Shift of "asr #32" is not allowed in Thumb2 mode.
4051   if (Val == 0x20) S = MCDisassembler::SoftFail;
4052   Inst.addOperand(MCOperand::CreateImm(Val));
4053   return S;
4054 }
4055 
4056 static DecodeStatus DecodeSwap(llvm::MCInst &Inst, unsigned Insn,
4057                                uint64_t Address, const void *Decoder) {
4058   unsigned Rt   = fieldFromInstruction32(Insn, 12, 4);
4059   unsigned Rt2  = fieldFromInstruction32(Insn, 0,  4);
4060   unsigned Rn   = fieldFromInstruction32(Insn, 16, 4);
4061   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
4062 
4063   if (pred == 0xF)
4064     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
4065 
4066   DecodeStatus S = MCDisassembler::Success;
4067   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
4068     return MCDisassembler::Fail;
4069   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt2, Address, Decoder)))
4070     return MCDisassembler::Fail;
4071   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
4072     return MCDisassembler::Fail;
4073   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4074     return MCDisassembler::Fail;
4075 
4076   return S;
4077 }
4078