xref: /llvm-project/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp (revision b925e935d7fd17814304bb29b52e8ed4a25ed3be)
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/ARMBaseInfo.h"
17 #include "llvm/MC/EDInstInfo.h"
18 #include "llvm/MC/MCInst.h"
19 #include "llvm/MC/MCExpr.h"
20 #include "llvm/MC/MCContext.h"
21 #include "llvm/MC/MCDisassembler.h"
22 #include "llvm/Support/Debug.h"
23 #include "llvm/Support/MemoryObject.h"
24 #include "llvm/Support/ErrorHandling.h"
25 #include "llvm/Support/TargetRegistry.h"
26 #include "llvm/Support/raw_ostream.h"
27 
28 using namespace llvm;
29 
30 typedef MCDisassembler::DecodeStatus DecodeStatus;
31 
32 namespace {
33 /// ARMDisassembler - ARM disassembler for all ARM platforms.
34 class ARMDisassembler : public MCDisassembler {
35 public:
36   /// Constructor     - Initializes the disassembler.
37   ///
38   ARMDisassembler(const MCSubtargetInfo &STI) :
39     MCDisassembler(STI) {
40   }
41 
42   ~ARMDisassembler() {
43   }
44 
45   /// getInstruction - See MCDisassembler.
46   DecodeStatus getInstruction(MCInst &instr,
47                               uint64_t &size,
48                               const MemoryObject &region,
49                               uint64_t address,
50                               raw_ostream &vStream,
51                               raw_ostream &cStream) const;
52 
53   /// getEDInfo - See MCDisassembler.
54   EDInstInfo *getEDInfo() const;
55 private:
56 };
57 
58 /// ThumbDisassembler - Thumb disassembler for all Thumb platforms.
59 class ThumbDisassembler : public MCDisassembler {
60 public:
61   /// Constructor     - Initializes the disassembler.
62   ///
63   ThumbDisassembler(const MCSubtargetInfo &STI) :
64     MCDisassembler(STI) {
65   }
66 
67   ~ThumbDisassembler() {
68   }
69 
70   /// getInstruction - See MCDisassembler.
71   DecodeStatus getInstruction(MCInst &instr,
72                               uint64_t &size,
73                               const MemoryObject &region,
74                               uint64_t address,
75                               raw_ostream &vStream,
76                               raw_ostream &cStream) const;
77 
78   /// getEDInfo - See MCDisassembler.
79   EDInstInfo *getEDInfo() const;
80 private:
81   mutable std::vector<unsigned> ITBlock;
82   DecodeStatus AddThumbPredicate(MCInst&) const;
83   void UpdateThumbVFPPredicate(MCInst&) const;
84 };
85 }
86 
87 static bool Check(DecodeStatus &Out, DecodeStatus In) {
88   switch (In) {
89     case MCDisassembler::Success:
90       // Out stays the same.
91       return true;
92     case MCDisassembler::SoftFail:
93       Out = In;
94       return true;
95     case MCDisassembler::Fail:
96       Out = In;
97       return false;
98   }
99   return false;
100 }
101 
102 
103 // Forward declare these because the autogenerated code will reference them.
104 // Definitions are further down.
105 static DecodeStatus DecodeGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
106                                    uint64_t Address, const void *Decoder);
107 static DecodeStatus DecodeGPRnopcRegisterClass(llvm::MCInst &Inst,
108                                                unsigned RegNo, uint64_t Address,
109                                                const void *Decoder);
110 static DecodeStatus DecodetGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
111                                    uint64_t Address, const void *Decoder);
112 static DecodeStatus DecodetcGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
113                                    uint64_t Address, const void *Decoder);
114 static DecodeStatus DecoderGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
115                                    uint64_t Address, const void *Decoder);
116 static DecodeStatus DecodeSPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
117                                    uint64_t Address, const void *Decoder);
118 static DecodeStatus DecodeDPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
119                                    uint64_t Address, const void *Decoder);
120 static DecodeStatus DecodeDPR_8RegisterClass(llvm::MCInst &Inst, unsigned RegNo,
121                                    uint64_t Address, const void *Decoder);
122 static DecodeStatus DecodeDPR_VFP2RegisterClass(llvm::MCInst &Inst,
123                                                 unsigned RegNo,
124                                                 uint64_t Address,
125                                                 const void *Decoder);
126 static DecodeStatus DecodeQPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
127                                    uint64_t Address, const void *Decoder);
128 
129 static DecodeStatus DecodePredicateOperand(llvm::MCInst &Inst, unsigned Val,
130                                uint64_t Address, const void *Decoder);
131 static DecodeStatus DecodeCCOutOperand(llvm::MCInst &Inst, unsigned Val,
132                                uint64_t Address, const void *Decoder);
133 static DecodeStatus DecodeSOImmOperand(llvm::MCInst &Inst, unsigned Val,
134                                uint64_t Address, const void *Decoder);
135 static DecodeStatus DecodeRegListOperand(llvm::MCInst &Inst, unsigned Val,
136                                uint64_t Address, const void *Decoder);
137 static DecodeStatus DecodeSPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
138                                uint64_t Address, const void *Decoder);
139 static DecodeStatus DecodeDPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
140                                uint64_t Address, const void *Decoder);
141 
142 static DecodeStatus DecodeBitfieldMaskOperand(llvm::MCInst &Inst, unsigned Insn,
143                                uint64_t Address, const void *Decoder);
144 static DecodeStatus DecodeCopMemInstruction(llvm::MCInst &Inst, unsigned Insn,
145                                uint64_t Address, const void *Decoder);
146 static DecodeStatus DecodeAddrMode2IdxInstruction(llvm::MCInst &Inst,
147                                                   unsigned Insn,
148                                                   uint64_t Address,
149                                                   const void *Decoder);
150 static DecodeStatus DecodeSORegMemOperand(llvm::MCInst &Inst, unsigned Insn,
151                                uint64_t Address, const void *Decoder);
152 static DecodeStatus DecodeAddrMode3Instruction(llvm::MCInst &Inst,unsigned Insn,
153                                uint64_t Address, const void *Decoder);
154 static DecodeStatus DecodeSORegImmOperand(llvm::MCInst &Inst, unsigned Insn,
155                                uint64_t Address, const void *Decoder);
156 static DecodeStatus DecodeSORegRegOperand(llvm::MCInst &Inst, unsigned Insn,
157                                uint64_t Address, const void *Decoder);
158 
159 static DecodeStatus DecodeMemMultipleWritebackInstruction(llvm::MCInst & Inst,
160                                                   unsigned Insn,
161                                                   uint64_t Adddress,
162                                                   const void *Decoder);
163 static DecodeStatus DecodeSMLAInstruction(llvm::MCInst &Inst, unsigned Insn,
164                                uint64_t Address, const void *Decoder);
165 static DecodeStatus DecodeCPSInstruction(llvm::MCInst &Inst, unsigned Insn,
166                                uint64_t Address, const void *Decoder);
167 static DecodeStatus DecodeT2CPSInstruction(llvm::MCInst &Inst, unsigned Insn,
168                                uint64_t Address, const void *Decoder);
169 static DecodeStatus DecodeAddrModeImm12Operand(llvm::MCInst &Inst, unsigned Val,
170                                uint64_t Address, const void *Decoder);
171 static DecodeStatus DecodeAddrMode5Operand(llvm::MCInst &Inst, unsigned Val,
172                                uint64_t Address, const void *Decoder);
173 static DecodeStatus DecodeAddrMode7Operand(llvm::MCInst &Inst, unsigned Val,
174                                uint64_t Address, const void *Decoder);
175 static DecodeStatus DecodeBranchImmInstruction(llvm::MCInst &Inst,unsigned Insn,
176                                uint64_t Address, const void *Decoder);
177 static DecodeStatus DecodeVCVTImmOperand(llvm::MCInst &Inst, unsigned Val,
178                                uint64_t Address, const void *Decoder);
179 static DecodeStatus DecodeAddrMode6Operand(llvm::MCInst &Inst, unsigned Val,
180                                uint64_t Address, const void *Decoder);
181 static DecodeStatus DecodeVLDInstruction(llvm::MCInst &Inst, unsigned Val,
182                                uint64_t Address, const void *Decoder);
183 static DecodeStatus DecodeVSTInstruction(llvm::MCInst &Inst, unsigned Val,
184                                uint64_t Address, const void *Decoder);
185 static DecodeStatus DecodeVLD1DupInstruction(llvm::MCInst &Inst, unsigned Val,
186                                uint64_t Address, const void *Decoder);
187 static DecodeStatus DecodeVLD2DupInstruction(llvm::MCInst &Inst, unsigned Val,
188                                uint64_t Address, const void *Decoder);
189 static DecodeStatus DecodeVLD3DupInstruction(llvm::MCInst &Inst, unsigned Val,
190                                uint64_t Address, const void *Decoder);
191 static DecodeStatus DecodeVLD4DupInstruction(llvm::MCInst &Inst, unsigned Val,
192                                uint64_t Address, const void *Decoder);
193 static DecodeStatus DecodeNEONModImmInstruction(llvm::MCInst &Inst,unsigned Val,
194                                uint64_t Address, const void *Decoder);
195 static DecodeStatus DecodeVSHLMaxInstruction(llvm::MCInst &Inst, unsigned Val,
196                                uint64_t Address, const void *Decoder);
197 static DecodeStatus DecodeShiftRight8Imm(llvm::MCInst &Inst, unsigned Val,
198                                uint64_t Address, const void *Decoder);
199 static DecodeStatus DecodeShiftRight16Imm(llvm::MCInst &Inst, unsigned Val,
200                                uint64_t Address, const void *Decoder);
201 static DecodeStatus DecodeShiftRight32Imm(llvm::MCInst &Inst, unsigned Val,
202                                uint64_t Address, const void *Decoder);
203 static DecodeStatus DecodeShiftRight64Imm(llvm::MCInst &Inst, unsigned Val,
204                                uint64_t Address, const void *Decoder);
205 static DecodeStatus DecodeTBLInstruction(llvm::MCInst &Inst, unsigned Insn,
206                                uint64_t Address, const void *Decoder);
207 static DecodeStatus DecodeVFPfpImm(llvm::MCInst &Inst, unsigned Val,
208                                uint64_t Address, const void *Decoder);
209 static DecodeStatus DecodePostIdxReg(llvm::MCInst &Inst, unsigned Insn,
210                                uint64_t Address, const void *Decoder);
211 static DecodeStatus DecodeCoprocessor(llvm::MCInst &Inst, unsigned Insn,
212                                uint64_t Address, const void *Decoder);
213 static DecodeStatus DecodeMemBarrierOption(llvm::MCInst &Inst, unsigned Insn,
214                                uint64_t Address, const void *Decoder);
215 static DecodeStatus DecodeMSRMask(llvm::MCInst &Inst, unsigned Insn,
216                                uint64_t Address, const void *Decoder);
217 static DecodeStatus DecodeDoubleRegLoad(llvm::MCInst &Inst, unsigned Insn,
218                                uint64_t Address, const void *Decoder);
219 static DecodeStatus DecodeDoubleRegStore(llvm::MCInst &Inst, unsigned Insn,
220                                uint64_t Address, const void *Decoder);
221 static DecodeStatus DecodeLDRPreImm(llvm::MCInst &Inst, unsigned Insn,
222                                uint64_t Address, const void *Decoder);
223 static DecodeStatus DecodeLDRPreReg(llvm::MCInst &Inst, unsigned Insn,
224                                uint64_t Address, const void *Decoder);
225 static DecodeStatus DecodeSTRPreImm(llvm::MCInst &Inst, unsigned Insn,
226                                uint64_t Address, const void *Decoder);
227 static DecodeStatus DecodeSTRPreReg(llvm::MCInst &Inst, unsigned Insn,
228                                uint64_t Address, const void *Decoder);
229 static DecodeStatus DecodeVLD1LN(llvm::MCInst &Inst, unsigned Insn,
230                                uint64_t Address, const void *Decoder);
231 static DecodeStatus DecodeVLD2LN(llvm::MCInst &Inst, unsigned Insn,
232                                uint64_t Address, const void *Decoder);
233 static DecodeStatus DecodeVLD3LN(llvm::MCInst &Inst, unsigned Insn,
234                                uint64_t Address, const void *Decoder);
235 static DecodeStatus DecodeVLD4LN(llvm::MCInst &Inst, unsigned Insn,
236                                uint64_t Address, const void *Decoder);
237 static DecodeStatus DecodeVST1LN(llvm::MCInst &Inst, unsigned Insn,
238                                uint64_t Address, const void *Decoder);
239 static DecodeStatus DecodeVST2LN(llvm::MCInst &Inst, unsigned Insn,
240                                uint64_t Address, const void *Decoder);
241 static DecodeStatus DecodeVST3LN(llvm::MCInst &Inst, unsigned Insn,
242                                uint64_t Address, const void *Decoder);
243 static DecodeStatus DecodeVST4LN(llvm::MCInst &Inst, unsigned Insn,
244                                uint64_t Address, const void *Decoder);
245 static DecodeStatus DecodeVMOVSRR(llvm::MCInst &Inst, unsigned Insn,
246                                uint64_t Address, const void *Decoder);
247 static DecodeStatus DecodeVMOVRRS(llvm::MCInst &Inst, unsigned Insn,
248                                uint64_t Address, const void *Decoder);
249 
250 static DecodeStatus DecodeThumbAddSpecialReg(llvm::MCInst &Inst, uint16_t Insn,
251                                uint64_t Address, const void *Decoder);
252 static DecodeStatus DecodeThumbBROperand(llvm::MCInst &Inst, unsigned Val,
253                                uint64_t Address, const void *Decoder);
254 static DecodeStatus DecodeT2BROperand(llvm::MCInst &Inst, unsigned Val,
255                                uint64_t Address, const void *Decoder);
256 static DecodeStatus DecodeThumbCmpBROperand(llvm::MCInst &Inst, unsigned Val,
257                                uint64_t Address, const void *Decoder);
258 static DecodeStatus DecodeThumbAddrModeRR(llvm::MCInst &Inst, unsigned Val,
259                                uint64_t Address, const void *Decoder);
260 static DecodeStatus DecodeThumbAddrModeIS(llvm::MCInst &Inst, unsigned Val,
261                                uint64_t Address, const void *Decoder);
262 static DecodeStatus DecodeThumbAddrModePC(llvm::MCInst &Inst, unsigned Val,
263                                uint64_t Address, const void *Decoder);
264 static DecodeStatus DecodeThumbAddrModeSP(llvm::MCInst &Inst, unsigned Val,
265                                uint64_t Address, const void *Decoder);
266 static DecodeStatus DecodeT2AddrModeSOReg(llvm::MCInst &Inst, unsigned Val,
267                                uint64_t Address, const void *Decoder);
268 static DecodeStatus DecodeT2LoadShift(llvm::MCInst &Inst, unsigned Val,
269                                uint64_t Address, const void *Decoder);
270 static DecodeStatus DecodeT2Imm8S4(llvm::MCInst &Inst, unsigned Val,
271                                uint64_t Address, const void *Decoder);
272 static DecodeStatus DecodeT2AddrModeImm8s4(llvm::MCInst &Inst, unsigned Val,
273                                uint64_t Address, const void *Decoder);
274 static DecodeStatus DecodeT2AddrModeImm0_1020s4(llvm::MCInst &Inst,unsigned Val,
275                                uint64_t Address, const void *Decoder);
276 static DecodeStatus DecodeT2Imm8(llvm::MCInst &Inst, unsigned Val,
277                                uint64_t Address, const void *Decoder);
278 static DecodeStatus DecodeT2AddrModeImm8(llvm::MCInst &Inst, unsigned Val,
279                                uint64_t Address, const void *Decoder);
280 static DecodeStatus DecodeThumbAddSPImm(llvm::MCInst &Inst, uint16_t Val,
281                                uint64_t Address, const void *Decoder);
282 static DecodeStatus DecodeThumbAddSPReg(llvm::MCInst &Inst, uint16_t Insn,
283                                 uint64_t Address, const void *Decoder);
284 static DecodeStatus DecodeThumbCPS(llvm::MCInst &Inst, uint16_t Insn,
285                                 uint64_t Address, const void *Decoder);
286 static DecodeStatus DecodeThumbBLXOffset(llvm::MCInst &Inst, unsigned Insn,
287                                 uint64_t Address, const void *Decoder);
288 static DecodeStatus DecodeT2AddrModeImm12(llvm::MCInst &Inst, unsigned Val,
289                                 uint64_t Address, const void *Decoder);
290 static DecodeStatus DecodeThumb2BCCInstruction(llvm::MCInst &Inst, unsigned Val,
291                                 uint64_t Address, const void *Decoder);
292 static DecodeStatus DecodeT2SOImm(llvm::MCInst &Inst, unsigned Val,
293                                 uint64_t Address, const void *Decoder);
294 static DecodeStatus DecodeThumbBCCTargetOperand(llvm::MCInst &Inst,unsigned Val,
295                                 uint64_t Address, const void *Decoder);
296 static DecodeStatus DecodeThumbBLTargetOperand(llvm::MCInst &Inst, unsigned Val,
297                                 uint64_t Address, const void *Decoder);
298 static DecodeStatus DecodeIT(llvm::MCInst &Inst, unsigned Val,
299                                 uint64_t Address, const void *Decoder);
300 static DecodeStatus DecodeT2LDRDPreInstruction(llvm::MCInst &Inst,unsigned Insn,
301                                uint64_t Address, const void *Decoder);
302 static DecodeStatus DecodeT2STRDPreInstruction(llvm::MCInst &Inst,unsigned Insn,
303                                uint64_t Address, const void *Decoder);
304 static DecodeStatus DecodeT2Adr(llvm::MCInst &Inst, unsigned Val,
305                                 uint64_t Address, const void *Decoder);
306 static DecodeStatus DecodeT2LdStPre(llvm::MCInst &Inst, unsigned Val,
307                                 uint64_t Address, const void *Decoder);
308 
309 
310 #include "ARMGenDisassemblerTables.inc"
311 #include "ARMGenInstrInfo.inc"
312 #include "ARMGenEDInfo.inc"
313 
314 static MCDisassembler *createARMDisassembler(const Target &T, const MCSubtargetInfo &STI) {
315   return new ARMDisassembler(STI);
316 }
317 
318 static MCDisassembler *createThumbDisassembler(const Target &T, const MCSubtargetInfo &STI) {
319   return new ThumbDisassembler(STI);
320 }
321 
322 EDInstInfo *ARMDisassembler::getEDInfo() const {
323   return instInfoARM;
324 }
325 
326 EDInstInfo *ThumbDisassembler::getEDInfo() const {
327   return instInfoARM;
328 }
329 
330 DecodeStatus ARMDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
331                                              const MemoryObject &Region,
332                                              uint64_t Address,
333                                              raw_ostream &os,
334                                              raw_ostream &cs) const {
335   uint8_t bytes[4];
336 
337   assert(!(STI.getFeatureBits() & ARM::ModeThumb) &&
338          "Asked to disassemble an ARM instruction but Subtarget is in Thumb mode!");
339 
340   // We want to read exactly 4 bytes of data.
341   if (Region.readBytes(Address, 4, (uint8_t*)bytes, NULL) == -1) {
342     Size = 0;
343     return MCDisassembler::Fail;
344   }
345 
346   // Encoded as a small-endian 32-bit word in the stream.
347   uint32_t insn = (bytes[3] << 24) |
348                   (bytes[2] << 16) |
349                   (bytes[1] <<  8) |
350                   (bytes[0] <<  0);
351 
352   // Calling the auto-generated decoder function.
353   DecodeStatus result = decodeARMInstruction32(MI, insn, Address, this, STI);
354   if (result != MCDisassembler::Fail) {
355     Size = 4;
356     return result;
357   }
358 
359   // VFP and NEON instructions, similarly, are shared between ARM
360   // and Thumb modes.
361   MI.clear();
362   result = decodeVFPInstruction32(MI, insn, Address, this, STI);
363   if (result != MCDisassembler::Fail) {
364     Size = 4;
365     return result;
366   }
367 
368   MI.clear();
369   result = decodeNEONDataInstruction32(MI, insn, Address, this, STI);
370   if (result != MCDisassembler::Fail) {
371     Size = 4;
372     // Add a fake predicate operand, because we share these instruction
373     // definitions with Thumb2 where these instructions are predicable.
374     if (!DecodePredicateOperand(MI, 0xE, Address, this))
375       return MCDisassembler::Fail;
376     return result;
377   }
378 
379   MI.clear();
380   result = decodeNEONLoadStoreInstruction32(MI, insn, Address, this, STI);
381   if (result != MCDisassembler::Fail) {
382     Size = 4;
383     // Add a fake predicate operand, because we share these instruction
384     // definitions with Thumb2 where these instructions are predicable.
385     if (!DecodePredicateOperand(MI, 0xE, Address, this))
386       return MCDisassembler::Fail;
387     return result;
388   }
389 
390   MI.clear();
391   result = decodeNEONDupInstruction32(MI, insn, Address, this, STI);
392   if (result != MCDisassembler::Fail) {
393     Size = 4;
394     // Add a fake predicate operand, because we share these instruction
395     // definitions with Thumb2 where these instructions are predicable.
396     if (!DecodePredicateOperand(MI, 0xE, Address, this))
397       return MCDisassembler::Fail;
398     return result;
399   }
400 
401   MI.clear();
402 
403   Size = 0;
404   return MCDisassembler::Fail;
405 }
406 
407 namespace llvm {
408 extern MCInstrDesc ARMInsts[];
409 }
410 
411 // Thumb1 instructions don't have explicit S bits.  Rather, they
412 // implicitly set CPSR.  Since it's not represented in the encoding, the
413 // auto-generated decoder won't inject the CPSR operand.  We need to fix
414 // that as a post-pass.
415 static void AddThumb1SBit(MCInst &MI, bool InITBlock) {
416   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
417   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
418   MCInst::iterator I = MI.begin();
419   for (unsigned i = 0; i < NumOps; ++i, ++I) {
420     if (I == MI.end()) break;
421     if (OpInfo[i].isOptionalDef() && OpInfo[i].RegClass == ARM::CCRRegClassID) {
422       if (i > 0 && OpInfo[i-1].isPredicate()) continue;
423       MI.insert(I, MCOperand::CreateReg(InITBlock ? 0 : ARM::CPSR));
424       return;
425     }
426   }
427 
428   MI.insert(I, MCOperand::CreateReg(InITBlock ? 0 : ARM::CPSR));
429 }
430 
431 // Most Thumb instructions don't have explicit predicates in the
432 // encoding, but rather get their predicates from IT context.  We need
433 // to fix up the predicate operands using this context information as a
434 // post-pass.
435 MCDisassembler::DecodeStatus
436 ThumbDisassembler::AddThumbPredicate(MCInst &MI) const {
437   MCDisassembler::DecodeStatus S = Success;
438 
439   // A few instructions actually have predicates encoded in them.  Don't
440   // try to overwrite it if we're seeing one of those.
441   switch (MI.getOpcode()) {
442     case ARM::tBcc:
443     case ARM::t2Bcc:
444     case ARM::tCBZ:
445     case ARM::tCBNZ:
446       // Some instructions (mostly conditional branches) are not
447       // allowed in IT blocks.
448       if (!ITBlock.empty())
449         S = SoftFail;
450       else
451         return Success;
452       break;
453     case ARM::tB:
454     case ARM::t2B:
455       // Some instructions (mostly unconditional branches) can
456       // only appears at the end of, or outside of, an IT.
457       if (ITBlock.size() > 1)
458         S = SoftFail;
459       break;
460     default:
461       break;
462   }
463 
464   // If we're in an IT block, base the predicate on that.  Otherwise,
465   // assume a predicate of AL.
466   unsigned CC;
467   if (!ITBlock.empty()) {
468     CC = ITBlock.back();
469     if (CC == 0xF)
470       CC = ARMCC::AL;
471     ITBlock.pop_back();
472   } else
473     CC = ARMCC::AL;
474 
475   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
476   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
477   MCInst::iterator I = MI.begin();
478   for (unsigned i = 0; i < NumOps; ++i, ++I) {
479     if (I == MI.end()) break;
480     if (OpInfo[i].isPredicate()) {
481       I = MI.insert(I, MCOperand::CreateImm(CC));
482       ++I;
483       if (CC == ARMCC::AL)
484         MI.insert(I, MCOperand::CreateReg(0));
485       else
486         MI.insert(I, MCOperand::CreateReg(ARM::CPSR));
487       return S;
488     }
489   }
490 
491   I = MI.insert(I, MCOperand::CreateImm(CC));
492   ++I;
493   if (CC == ARMCC::AL)
494     MI.insert(I, MCOperand::CreateReg(0));
495   else
496     MI.insert(I, MCOperand::CreateReg(ARM::CPSR));
497 
498   return S;
499 }
500 
501 // Thumb VFP instructions are a special case.  Because we share their
502 // encodings between ARM and Thumb modes, and they are predicable in ARM
503 // mode, the auto-generated decoder will give them an (incorrect)
504 // predicate operand.  We need to rewrite these operands based on the IT
505 // context as a post-pass.
506 void ThumbDisassembler::UpdateThumbVFPPredicate(MCInst &MI) const {
507   unsigned CC;
508   if (!ITBlock.empty()) {
509     CC = ITBlock.back();
510     ITBlock.pop_back();
511   } else
512     CC = ARMCC::AL;
513 
514   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
515   MCInst::iterator I = MI.begin();
516   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
517   for (unsigned i = 0; i < NumOps; ++i, ++I) {
518     if (OpInfo[i].isPredicate() ) {
519       I->setImm(CC);
520       ++I;
521       if (CC == ARMCC::AL)
522         I->setReg(0);
523       else
524         I->setReg(ARM::CPSR);
525       return;
526     }
527   }
528 }
529 
530 DecodeStatus ThumbDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
531                                                const MemoryObject &Region,
532                                                uint64_t Address,
533                                                raw_ostream &os,
534                                                raw_ostream &cs) const {
535   uint8_t bytes[4];
536 
537   assert((STI.getFeatureBits() & ARM::ModeThumb) &&
538          "Asked to disassemble in Thumb mode but Subtarget is in ARM mode!");
539 
540   // We want to read exactly 2 bytes of data.
541   if (Region.readBytes(Address, 2, (uint8_t*)bytes, NULL) == -1) {
542     Size = 0;
543     return MCDisassembler::Fail;
544   }
545 
546   uint16_t insn16 = (bytes[1] << 8) | bytes[0];
547   DecodeStatus result = decodeThumbInstruction16(MI, insn16, Address, this, STI);
548   if (result != MCDisassembler::Fail) {
549     Size = 2;
550     Check(result, AddThumbPredicate(MI));
551     return result;
552   }
553 
554   MI.clear();
555   result = decodeThumbSBitInstruction16(MI, insn16, Address, this, STI);
556   if (result) {
557     Size = 2;
558     bool InITBlock = !ITBlock.empty();
559     Check(result, AddThumbPredicate(MI));
560     AddThumb1SBit(MI, InITBlock);
561     return result;
562   }
563 
564   MI.clear();
565   result = decodeThumb2Instruction16(MI, insn16, Address, this, STI);
566   if (result != MCDisassembler::Fail) {
567     Size = 2;
568     Check(result, AddThumbPredicate(MI));
569 
570     // If we find an IT instruction, we need to parse its condition
571     // code and mask operands so that we can apply them correctly
572     // to the subsequent instructions.
573     if (MI.getOpcode() == ARM::t2IT) {
574       // Nested IT blocks are UNPREDICTABLE.
575       if (!ITBlock.empty())
576         return MCDisassembler::SoftFail;
577 
578       // (3 - the number of trailing zeros) is the number of then / else.
579       unsigned firstcond = MI.getOperand(0).getImm();
580       unsigned Mask = MI.getOperand(1).getImm();
581       unsigned CondBit0 = Mask >> 4 & 1;
582       unsigned NumTZ = CountTrailingZeros_32(Mask);
583       assert(NumTZ <= 3 && "Invalid IT mask!");
584       for (unsigned Pos = 3, e = NumTZ; Pos > e; --Pos) {
585         bool T = ((Mask >> Pos) & 1) == CondBit0;
586         if (T)
587           ITBlock.insert(ITBlock.begin(), firstcond);
588         else
589           ITBlock.insert(ITBlock.begin(), firstcond ^ 1);
590       }
591 
592       ITBlock.push_back(firstcond);
593     }
594 
595     return result;
596   }
597 
598   // We want to read exactly 4 bytes of data.
599   if (Region.readBytes(Address, 4, (uint8_t*)bytes, NULL) == -1) {
600     Size = 0;
601     return MCDisassembler::Fail;
602   }
603 
604   uint32_t insn32 = (bytes[3] <<  8) |
605                     (bytes[2] <<  0) |
606                     (bytes[1] << 24) |
607                     (bytes[0] << 16);
608   MI.clear();
609   result = decodeThumbInstruction32(MI, insn32, Address, this, STI);
610   if (result != MCDisassembler::Fail) {
611     Size = 4;
612     bool InITBlock = ITBlock.size();
613     Check(result, AddThumbPredicate(MI));
614     AddThumb1SBit(MI, InITBlock);
615     return result;
616   }
617 
618   MI.clear();
619   result = decodeThumb2Instruction32(MI, insn32, Address, this, STI);
620   if (result != MCDisassembler::Fail) {
621     Size = 4;
622     Check(result, AddThumbPredicate(MI));
623     return result;
624   }
625 
626   MI.clear();
627   result = decodeVFPInstruction32(MI, insn32, Address, this, STI);
628   if (result != MCDisassembler::Fail) {
629     Size = 4;
630     UpdateThumbVFPPredicate(MI);
631     return result;
632   }
633 
634   MI.clear();
635   result = decodeNEONDupInstruction32(MI, insn32, Address, this, STI);
636   if (result != MCDisassembler::Fail) {
637     Size = 4;
638     Check(result, AddThumbPredicate(MI));
639     return result;
640   }
641 
642   if (fieldFromInstruction32(insn32, 24, 8) == 0xF9) {
643     MI.clear();
644     uint32_t NEONLdStInsn = insn32;
645     NEONLdStInsn &= 0xF0FFFFFF;
646     NEONLdStInsn |= 0x04000000;
647     result = decodeNEONLoadStoreInstruction32(MI, NEONLdStInsn, Address, this, STI);
648     if (result != MCDisassembler::Fail) {
649       Size = 4;
650       Check(result, AddThumbPredicate(MI));
651       return result;
652     }
653   }
654 
655   if (fieldFromInstruction32(insn32, 24, 4) == 0xF) {
656     MI.clear();
657     uint32_t NEONDataInsn = insn32;
658     NEONDataInsn &= 0xF0FFFFFF; // Clear bits 27-24
659     NEONDataInsn |= (NEONDataInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
660     NEONDataInsn |= 0x12000000; // Set bits 28 and 25
661     result = decodeNEONDataInstruction32(MI, NEONDataInsn, Address, this, STI);
662     if (result != MCDisassembler::Fail) {
663       Size = 4;
664       Check(result, AddThumbPredicate(MI));
665       return result;
666     }
667   }
668 
669   Size = 0;
670   return MCDisassembler::Fail;
671 }
672 
673 
674 extern "C" void LLVMInitializeARMDisassembler() {
675   TargetRegistry::RegisterMCDisassembler(TheARMTarget,
676                                          createARMDisassembler);
677   TargetRegistry::RegisterMCDisassembler(TheThumbTarget,
678                                          createThumbDisassembler);
679 }
680 
681 static const unsigned GPRDecoderTable[] = {
682   ARM::R0, ARM::R1, ARM::R2, ARM::R3,
683   ARM::R4, ARM::R5, ARM::R6, ARM::R7,
684   ARM::R8, ARM::R9, ARM::R10, ARM::R11,
685   ARM::R12, ARM::SP, ARM::LR, ARM::PC
686 };
687 
688 static DecodeStatus DecodeGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
689                                    uint64_t Address, const void *Decoder) {
690   if (RegNo > 15)
691     return MCDisassembler::Fail;
692 
693   unsigned Register = GPRDecoderTable[RegNo];
694   Inst.addOperand(MCOperand::CreateReg(Register));
695   return MCDisassembler::Success;
696 }
697 
698 static DecodeStatus
699 DecodeGPRnopcRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
700                            uint64_t Address, const void *Decoder) {
701   if (RegNo == 15) return MCDisassembler::Fail;
702   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
703 }
704 
705 static DecodeStatus DecodetGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
706                                    uint64_t Address, const void *Decoder) {
707   if (RegNo > 7)
708     return MCDisassembler::Fail;
709   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
710 }
711 
712 static DecodeStatus DecodetcGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
713                                    uint64_t Address, const void *Decoder) {
714   unsigned Register = 0;
715   switch (RegNo) {
716     case 0:
717       Register = ARM::R0;
718       break;
719     case 1:
720       Register = ARM::R1;
721       break;
722     case 2:
723       Register = ARM::R2;
724       break;
725     case 3:
726       Register = ARM::R3;
727       break;
728     case 9:
729       Register = ARM::R9;
730       break;
731     case 12:
732       Register = ARM::R12;
733       break;
734     default:
735       return MCDisassembler::Fail;
736     }
737 
738   Inst.addOperand(MCOperand::CreateReg(Register));
739   return MCDisassembler::Success;
740 }
741 
742 static DecodeStatus DecoderGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
743                                    uint64_t Address, const void *Decoder) {
744   if (RegNo == 13 || RegNo == 15) return MCDisassembler::Fail;
745   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
746 }
747 
748 static const unsigned SPRDecoderTable[] = {
749      ARM::S0,  ARM::S1,  ARM::S2,  ARM::S3,
750      ARM::S4,  ARM::S5,  ARM::S6,  ARM::S7,
751      ARM::S8,  ARM::S9, ARM::S10, ARM::S11,
752     ARM::S12, ARM::S13, ARM::S14, ARM::S15,
753     ARM::S16, ARM::S17, ARM::S18, ARM::S19,
754     ARM::S20, ARM::S21, ARM::S22, ARM::S23,
755     ARM::S24, ARM::S25, ARM::S26, ARM::S27,
756     ARM::S28, ARM::S29, ARM::S30, ARM::S31
757 };
758 
759 static DecodeStatus DecodeSPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
760                                    uint64_t Address, const void *Decoder) {
761   if (RegNo > 31)
762     return MCDisassembler::Fail;
763 
764   unsigned Register = SPRDecoderTable[RegNo];
765   Inst.addOperand(MCOperand::CreateReg(Register));
766   return MCDisassembler::Success;
767 }
768 
769 static const unsigned DPRDecoderTable[] = {
770      ARM::D0,  ARM::D1,  ARM::D2,  ARM::D3,
771      ARM::D4,  ARM::D5,  ARM::D6,  ARM::D7,
772      ARM::D8,  ARM::D9, ARM::D10, ARM::D11,
773     ARM::D12, ARM::D13, ARM::D14, ARM::D15,
774     ARM::D16, ARM::D17, ARM::D18, ARM::D19,
775     ARM::D20, ARM::D21, ARM::D22, ARM::D23,
776     ARM::D24, ARM::D25, ARM::D26, ARM::D27,
777     ARM::D28, ARM::D29, ARM::D30, ARM::D31
778 };
779 
780 static DecodeStatus DecodeDPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
781                                    uint64_t Address, const void *Decoder) {
782   if (RegNo > 31)
783     return MCDisassembler::Fail;
784 
785   unsigned Register = DPRDecoderTable[RegNo];
786   Inst.addOperand(MCOperand::CreateReg(Register));
787   return MCDisassembler::Success;
788 }
789 
790 static DecodeStatus DecodeDPR_8RegisterClass(llvm::MCInst &Inst, unsigned RegNo,
791                                    uint64_t Address, const void *Decoder) {
792   if (RegNo > 7)
793     return MCDisassembler::Fail;
794   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
795 }
796 
797 static DecodeStatus
798 DecodeDPR_VFP2RegisterClass(llvm::MCInst &Inst, unsigned RegNo,
799                             uint64_t Address, const void *Decoder) {
800   if (RegNo > 15)
801     return MCDisassembler::Fail;
802   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
803 }
804 
805 static const unsigned QPRDecoderTable[] = {
806      ARM::Q0,  ARM::Q1,  ARM::Q2,  ARM::Q3,
807      ARM::Q4,  ARM::Q5,  ARM::Q6,  ARM::Q7,
808      ARM::Q8,  ARM::Q9, ARM::Q10, ARM::Q11,
809     ARM::Q12, ARM::Q13, ARM::Q14, ARM::Q15
810 };
811 
812 
813 static DecodeStatus DecodeQPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
814                                    uint64_t Address, const void *Decoder) {
815   if (RegNo > 31)
816     return MCDisassembler::Fail;
817   RegNo >>= 1;
818 
819   unsigned Register = QPRDecoderTable[RegNo];
820   Inst.addOperand(MCOperand::CreateReg(Register));
821   return MCDisassembler::Success;
822 }
823 
824 static DecodeStatus DecodePredicateOperand(llvm::MCInst &Inst, unsigned Val,
825                                uint64_t Address, const void *Decoder) {
826   if (Val == 0xF) return MCDisassembler::Fail;
827   // AL predicate is not allowed on Thumb1 branches.
828   if (Inst.getOpcode() == ARM::tBcc && Val == 0xE)
829     return MCDisassembler::Fail;
830   Inst.addOperand(MCOperand::CreateImm(Val));
831   if (Val == ARMCC::AL) {
832     Inst.addOperand(MCOperand::CreateReg(0));
833   } else
834     Inst.addOperand(MCOperand::CreateReg(ARM::CPSR));
835   return MCDisassembler::Success;
836 }
837 
838 static DecodeStatus DecodeCCOutOperand(llvm::MCInst &Inst, unsigned Val,
839                                uint64_t Address, const void *Decoder) {
840   if (Val)
841     Inst.addOperand(MCOperand::CreateReg(ARM::CPSR));
842   else
843     Inst.addOperand(MCOperand::CreateReg(0));
844   return MCDisassembler::Success;
845 }
846 
847 static DecodeStatus DecodeSOImmOperand(llvm::MCInst &Inst, unsigned Val,
848                                uint64_t Address, const void *Decoder) {
849   uint32_t imm = Val & 0xFF;
850   uint32_t rot = (Val & 0xF00) >> 7;
851   uint32_t rot_imm = (imm >> rot) | (imm << (32-rot));
852   Inst.addOperand(MCOperand::CreateImm(rot_imm));
853   return MCDisassembler::Success;
854 }
855 
856 static DecodeStatus DecodeSORegImmOperand(llvm::MCInst &Inst, unsigned Val,
857                                uint64_t Address, const void *Decoder) {
858   DecodeStatus S = MCDisassembler::Success;
859 
860   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
861   unsigned type = fieldFromInstruction32(Val, 5, 2);
862   unsigned imm = fieldFromInstruction32(Val, 7, 5);
863 
864   // Register-immediate
865   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
866     return MCDisassembler::Fail;
867 
868   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
869   switch (type) {
870     case 0:
871       Shift = ARM_AM::lsl;
872       break;
873     case 1:
874       Shift = ARM_AM::lsr;
875       break;
876     case 2:
877       Shift = ARM_AM::asr;
878       break;
879     case 3:
880       Shift = ARM_AM::ror;
881       break;
882   }
883 
884   if (Shift == ARM_AM::ror && imm == 0)
885     Shift = ARM_AM::rrx;
886 
887   unsigned Op = Shift | (imm << 3);
888   Inst.addOperand(MCOperand::CreateImm(Op));
889 
890   return S;
891 }
892 
893 static DecodeStatus DecodeSORegRegOperand(llvm::MCInst &Inst, unsigned Val,
894                                uint64_t Address, const void *Decoder) {
895   DecodeStatus S = MCDisassembler::Success;
896 
897   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
898   unsigned type = fieldFromInstruction32(Val, 5, 2);
899   unsigned Rs = fieldFromInstruction32(Val, 8, 4);
900 
901   // Register-register
902   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
903     return MCDisassembler::Fail;
904   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rs, Address, Decoder)))
905     return MCDisassembler::Fail;
906 
907   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
908   switch (type) {
909     case 0:
910       Shift = ARM_AM::lsl;
911       break;
912     case 1:
913       Shift = ARM_AM::lsr;
914       break;
915     case 2:
916       Shift = ARM_AM::asr;
917       break;
918     case 3:
919       Shift = ARM_AM::ror;
920       break;
921   }
922 
923   Inst.addOperand(MCOperand::CreateImm(Shift));
924 
925   return S;
926 }
927 
928 static DecodeStatus DecodeRegListOperand(llvm::MCInst &Inst, unsigned Val,
929                                  uint64_t Address, const void *Decoder) {
930   DecodeStatus S = MCDisassembler::Success;
931 
932   bool writebackLoad = false;
933   unsigned writebackReg = 0;
934   switch (Inst.getOpcode()) {
935     default:
936       break;
937     case ARM::LDMIA_UPD:
938     case ARM::LDMDB_UPD:
939     case ARM::LDMIB_UPD:
940     case ARM::LDMDA_UPD:
941     case ARM::t2LDMIA_UPD:
942     case ARM::t2LDMDB_UPD:
943       writebackLoad = true;
944       writebackReg = Inst.getOperand(0).getReg();
945       break;
946   }
947 
948   // Empty register lists are not allowed.
949   if (CountPopulation_32(Val) == 0) return MCDisassembler::Fail;
950   for (unsigned i = 0; i < 16; ++i) {
951     if (Val & (1 << i)) {
952       if (!Check(S, DecodeGPRRegisterClass(Inst, i, Address, Decoder)))
953         return MCDisassembler::Fail;
954       // Writeback not allowed if Rn is in the target list.
955       if (writebackLoad && writebackReg == Inst.end()[-1].getReg())
956         Check(S, MCDisassembler::SoftFail);
957     }
958   }
959 
960   return S;
961 }
962 
963 static DecodeStatus DecodeSPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
964                                  uint64_t Address, const void *Decoder) {
965   DecodeStatus S = MCDisassembler::Success;
966 
967   unsigned Vd = fieldFromInstruction32(Val, 8, 4);
968   unsigned regs = Val & 0xFF;
969 
970   if (!Check(S, DecodeSPRRegisterClass(Inst, Vd, Address, Decoder)))
971     return MCDisassembler::Fail;
972   for (unsigned i = 0; i < (regs - 1); ++i) {
973     if (!Check(S, DecodeSPRRegisterClass(Inst, ++Vd, Address, Decoder)))
974       return MCDisassembler::Fail;
975   }
976 
977   return S;
978 }
979 
980 static DecodeStatus DecodeDPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
981                                  uint64_t Address, const void *Decoder) {
982   DecodeStatus S = MCDisassembler::Success;
983 
984   unsigned Vd = fieldFromInstruction32(Val, 8, 4);
985   unsigned regs = (Val & 0xFF) / 2;
986 
987   if (!Check(S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)))
988       return MCDisassembler::Fail;
989   for (unsigned i = 0; i < (regs - 1); ++i) {
990     if (!Check(S, DecodeDPRRegisterClass(Inst, ++Vd, Address, Decoder)))
991       return MCDisassembler::Fail;
992   }
993 
994   return S;
995 }
996 
997 static DecodeStatus DecodeBitfieldMaskOperand(llvm::MCInst &Inst, unsigned Val,
998                                       uint64_t Address, const void *Decoder) {
999   // This operand encodes a mask of contiguous zeros between a specified MSB
1000   // and LSB.  To decode it, we create the mask of all bits MSB-and-lower,
1001   // the mask of all bits LSB-and-lower, and then xor them to create
1002   // the mask of that's all ones on [msb, lsb].  Finally we not it to
1003   // create the final mask.
1004   unsigned msb = fieldFromInstruction32(Val, 5, 5);
1005   unsigned lsb = fieldFromInstruction32(Val, 0, 5);
1006 
1007   uint32_t msb_mask = 0xFFFFFFFF;
1008   if (msb != 31) msb_mask = (1U << (msb+1)) - 1;
1009   uint32_t lsb_mask = (1U << lsb) - 1;
1010 
1011   Inst.addOperand(MCOperand::CreateImm(~(msb_mask ^ lsb_mask)));
1012   return MCDisassembler::Success;
1013 }
1014 
1015 static DecodeStatus DecodeCopMemInstruction(llvm::MCInst &Inst, unsigned Insn,
1016                                   uint64_t Address, const void *Decoder) {
1017   DecodeStatus S = MCDisassembler::Success;
1018 
1019   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1020   unsigned CRd = fieldFromInstruction32(Insn, 12, 4);
1021   unsigned coproc = fieldFromInstruction32(Insn, 8, 4);
1022   unsigned imm = fieldFromInstruction32(Insn, 0, 8);
1023   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1024   unsigned U = fieldFromInstruction32(Insn, 23, 1);
1025 
1026   switch (Inst.getOpcode()) {
1027     case ARM::LDC_OFFSET:
1028     case ARM::LDC_PRE:
1029     case ARM::LDC_POST:
1030     case ARM::LDC_OPTION:
1031     case ARM::LDCL_OFFSET:
1032     case ARM::LDCL_PRE:
1033     case ARM::LDCL_POST:
1034     case ARM::LDCL_OPTION:
1035     case ARM::STC_OFFSET:
1036     case ARM::STC_PRE:
1037     case ARM::STC_POST:
1038     case ARM::STC_OPTION:
1039     case ARM::STCL_OFFSET:
1040     case ARM::STCL_PRE:
1041     case ARM::STCL_POST:
1042     case ARM::STCL_OPTION:
1043     case ARM::t2LDC_OFFSET:
1044     case ARM::t2LDC_PRE:
1045     case ARM::t2LDC_POST:
1046     case ARM::t2LDC_OPTION:
1047     case ARM::t2LDCL_OFFSET:
1048     case ARM::t2LDCL_PRE:
1049     case ARM::t2LDCL_POST:
1050     case ARM::t2LDCL_OPTION:
1051     case ARM::t2STC_OFFSET:
1052     case ARM::t2STC_PRE:
1053     case ARM::t2STC_POST:
1054     case ARM::t2STC_OPTION:
1055     case ARM::t2STCL_OFFSET:
1056     case ARM::t2STCL_PRE:
1057     case ARM::t2STCL_POST:
1058     case ARM::t2STCL_OPTION:
1059       if (coproc == 0xA || coproc == 0xB)
1060         return MCDisassembler::Fail;
1061       break;
1062     default:
1063       break;
1064   }
1065 
1066   Inst.addOperand(MCOperand::CreateImm(coproc));
1067   Inst.addOperand(MCOperand::CreateImm(CRd));
1068   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1069     return MCDisassembler::Fail;
1070   switch (Inst.getOpcode()) {
1071     case ARM::LDC_OPTION:
1072     case ARM::LDCL_OPTION:
1073     case ARM::LDC2_OPTION:
1074     case ARM::LDC2L_OPTION:
1075     case ARM::STC_OPTION:
1076     case ARM::STCL_OPTION:
1077     case ARM::STC2_OPTION:
1078     case ARM::STC2L_OPTION:
1079     case ARM::LDCL_POST:
1080     case ARM::STCL_POST:
1081     case ARM::LDC2L_POST:
1082     case ARM::STC2L_POST:
1083     case ARM::t2LDC_OPTION:
1084     case ARM::t2LDCL_OPTION:
1085     case ARM::t2STC_OPTION:
1086     case ARM::t2STCL_OPTION:
1087     case ARM::t2LDCL_POST:
1088     case ARM::t2STCL_POST:
1089       break;
1090     default:
1091       Inst.addOperand(MCOperand::CreateReg(0));
1092       break;
1093   }
1094 
1095   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1096   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1097 
1098   bool writeback = (P == 0) || (W == 1);
1099   unsigned idx_mode = 0;
1100   if (P && writeback)
1101     idx_mode = ARMII::IndexModePre;
1102   else if (!P && writeback)
1103     idx_mode = ARMII::IndexModePost;
1104 
1105   switch (Inst.getOpcode()) {
1106     case ARM::LDCL_POST:
1107     case ARM::STCL_POST:
1108     case ARM::t2LDCL_POST:
1109     case ARM::t2STCL_POST:
1110     case ARM::LDC2L_POST:
1111     case ARM::STC2L_POST:
1112       imm |= U << 8;
1113     case ARM::LDC_OPTION:
1114     case ARM::LDCL_OPTION:
1115     case ARM::LDC2_OPTION:
1116     case ARM::LDC2L_OPTION:
1117     case ARM::STC_OPTION:
1118     case ARM::STCL_OPTION:
1119     case ARM::STC2_OPTION:
1120     case ARM::STC2L_OPTION:
1121     case ARM::t2LDC_OPTION:
1122     case ARM::t2LDCL_OPTION:
1123     case ARM::t2STC_OPTION:
1124     case ARM::t2STCL_OPTION:
1125       Inst.addOperand(MCOperand::CreateImm(imm));
1126       break;
1127     default:
1128       if (U)
1129         Inst.addOperand(MCOperand::CreateImm(
1130             ARM_AM::getAM2Opc(ARM_AM::add, imm, ARM_AM::lsl, idx_mode)));
1131       else
1132         Inst.addOperand(MCOperand::CreateImm(
1133             ARM_AM::getAM2Opc(ARM_AM::sub, imm, ARM_AM::lsl, idx_mode)));
1134       break;
1135   }
1136 
1137   switch (Inst.getOpcode()) {
1138     case ARM::LDC_OFFSET:
1139     case ARM::LDC_PRE:
1140     case ARM::LDC_POST:
1141     case ARM::LDC_OPTION:
1142     case ARM::LDCL_OFFSET:
1143     case ARM::LDCL_PRE:
1144     case ARM::LDCL_POST:
1145     case ARM::LDCL_OPTION:
1146     case ARM::STC_OFFSET:
1147     case ARM::STC_PRE:
1148     case ARM::STC_POST:
1149     case ARM::STC_OPTION:
1150     case ARM::STCL_OFFSET:
1151     case ARM::STCL_PRE:
1152     case ARM::STCL_POST:
1153     case ARM::STCL_OPTION:
1154       if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1155         return MCDisassembler::Fail;
1156       break;
1157     default:
1158       break;
1159   }
1160 
1161   return S;
1162 }
1163 
1164 static DecodeStatus
1165 DecodeAddrMode2IdxInstruction(llvm::MCInst &Inst, unsigned Insn,
1166                               uint64_t Address, const void *Decoder) {
1167   DecodeStatus S = MCDisassembler::Success;
1168 
1169   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1170   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
1171   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1172   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
1173   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1174   unsigned reg = fieldFromInstruction32(Insn, 25, 1);
1175   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1176   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1177 
1178   // On stores, the writeback operand precedes Rt.
1179   switch (Inst.getOpcode()) {
1180     case ARM::STR_POST_IMM:
1181     case ARM::STR_POST_REG:
1182     case ARM::STRB_POST_IMM:
1183     case ARM::STRB_POST_REG:
1184     case ARM::STRT_POST_REG:
1185     case ARM::STRT_POST_IMM:
1186     case ARM::STRBT_POST_REG:
1187     case ARM::STRBT_POST_IMM:
1188       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1189         return MCDisassembler::Fail;
1190       break;
1191     default:
1192       break;
1193   }
1194 
1195   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
1196     return MCDisassembler::Fail;
1197 
1198   // On loads, the writeback operand comes after Rt.
1199   switch (Inst.getOpcode()) {
1200     case ARM::LDR_POST_IMM:
1201     case ARM::LDR_POST_REG:
1202     case ARM::LDRB_POST_IMM:
1203     case ARM::LDRB_POST_REG:
1204     case ARM::LDRBT_POST_REG:
1205     case ARM::LDRBT_POST_IMM:
1206     case ARM::LDRT_POST_REG:
1207     case ARM::LDRT_POST_IMM:
1208       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1209         return MCDisassembler::Fail;
1210       break;
1211     default:
1212       break;
1213   }
1214 
1215   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1216     return MCDisassembler::Fail;
1217 
1218   ARM_AM::AddrOpc Op = ARM_AM::add;
1219   if (!fieldFromInstruction32(Insn, 23, 1))
1220     Op = ARM_AM::sub;
1221 
1222   bool writeback = (P == 0) || (W == 1);
1223   unsigned idx_mode = 0;
1224   if (P && writeback)
1225     idx_mode = ARMII::IndexModePre;
1226   else if (!P && writeback)
1227     idx_mode = ARMII::IndexModePost;
1228 
1229   if (writeback && (Rn == 15 || Rn == Rt))
1230     S = MCDisassembler::SoftFail; // UNPREDICTABLE
1231 
1232   if (reg) {
1233     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1234       return MCDisassembler::Fail;
1235     ARM_AM::ShiftOpc Opc = ARM_AM::lsl;
1236     switch( fieldFromInstruction32(Insn, 5, 2)) {
1237       case 0:
1238         Opc = ARM_AM::lsl;
1239         break;
1240       case 1:
1241         Opc = ARM_AM::lsr;
1242         break;
1243       case 2:
1244         Opc = ARM_AM::asr;
1245         break;
1246       case 3:
1247         Opc = ARM_AM::ror;
1248         break;
1249       default:
1250         return MCDisassembler::Fail;
1251     }
1252     unsigned amt = fieldFromInstruction32(Insn, 7, 5);
1253     unsigned imm = ARM_AM::getAM2Opc(Op, amt, Opc, idx_mode);
1254 
1255     Inst.addOperand(MCOperand::CreateImm(imm));
1256   } else {
1257     Inst.addOperand(MCOperand::CreateReg(0));
1258     unsigned tmp = ARM_AM::getAM2Opc(Op, imm, ARM_AM::lsl, idx_mode);
1259     Inst.addOperand(MCOperand::CreateImm(tmp));
1260   }
1261 
1262   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1263     return MCDisassembler::Fail;
1264 
1265   return S;
1266 }
1267 
1268 static DecodeStatus DecodeSORegMemOperand(llvm::MCInst &Inst, unsigned Val,
1269                                   uint64_t Address, const void *Decoder) {
1270   DecodeStatus S = MCDisassembler::Success;
1271 
1272   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
1273   unsigned Rm = fieldFromInstruction32(Val,  0, 4);
1274   unsigned type = fieldFromInstruction32(Val, 5, 2);
1275   unsigned imm = fieldFromInstruction32(Val, 7, 5);
1276   unsigned U = fieldFromInstruction32(Val, 12, 1);
1277 
1278   ARM_AM::ShiftOpc ShOp = ARM_AM::lsl;
1279   switch (type) {
1280     case 0:
1281       ShOp = ARM_AM::lsl;
1282       break;
1283     case 1:
1284       ShOp = ARM_AM::lsr;
1285       break;
1286     case 2:
1287       ShOp = ARM_AM::asr;
1288       break;
1289     case 3:
1290       ShOp = ARM_AM::ror;
1291       break;
1292   }
1293 
1294   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1295     return MCDisassembler::Fail;
1296   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1297     return MCDisassembler::Fail;
1298   unsigned shift;
1299   if (U)
1300     shift = ARM_AM::getAM2Opc(ARM_AM::add, imm, ShOp);
1301   else
1302     shift = ARM_AM::getAM2Opc(ARM_AM::sub, imm, ShOp);
1303   Inst.addOperand(MCOperand::CreateImm(shift));
1304 
1305   return S;
1306 }
1307 
1308 static DecodeStatus
1309 DecodeAddrMode3Instruction(llvm::MCInst &Inst, unsigned Insn,
1310                            uint64_t Address, const void *Decoder) {
1311   DecodeStatus S = MCDisassembler::Success;
1312 
1313   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
1314   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1315   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1316   unsigned type = fieldFromInstruction32(Insn, 22, 1);
1317   unsigned imm = fieldFromInstruction32(Insn, 8, 4);
1318   unsigned U = ((~fieldFromInstruction32(Insn, 23, 1)) & 1) << 8;
1319   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1320   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1321   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1322 
1323   bool writeback = (W == 1) | (P == 0);
1324 
1325   // For {LD,ST}RD, Rt must be even, else undefined.
1326   switch (Inst.getOpcode()) {
1327     case ARM::STRD:
1328     case ARM::STRD_PRE:
1329     case ARM::STRD_POST:
1330     case ARM::LDRD:
1331     case ARM::LDRD_PRE:
1332     case ARM::LDRD_POST:
1333       if (Rt & 0x1) return MCDisassembler::Fail;
1334       break;
1335     default:
1336       break;
1337   }
1338 
1339   if (writeback) { // Writeback
1340     if (P)
1341       U |= ARMII::IndexModePre << 9;
1342     else
1343       U |= ARMII::IndexModePost << 9;
1344 
1345     // On stores, the writeback operand precedes Rt.
1346     switch (Inst.getOpcode()) {
1347     case ARM::STRD:
1348     case ARM::STRD_PRE:
1349     case ARM::STRD_POST:
1350     case ARM::STRH:
1351     case ARM::STRH_PRE:
1352     case ARM::STRH_POST:
1353       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1354         return MCDisassembler::Fail;
1355       break;
1356     default:
1357       break;
1358     }
1359   }
1360 
1361   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
1362     return MCDisassembler::Fail;
1363   switch (Inst.getOpcode()) {
1364     case ARM::STRD:
1365     case ARM::STRD_PRE:
1366     case ARM::STRD_POST:
1367     case ARM::LDRD:
1368     case ARM::LDRD_PRE:
1369     case ARM::LDRD_POST:
1370       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
1371         return MCDisassembler::Fail;
1372       break;
1373     default:
1374       break;
1375   }
1376 
1377   if (writeback) {
1378     // On loads, the writeback operand comes after Rt.
1379     switch (Inst.getOpcode()) {
1380     case ARM::LDRD:
1381     case ARM::LDRD_PRE:
1382     case ARM::LDRD_POST:
1383     case ARM::LDRH:
1384     case ARM::LDRH_PRE:
1385     case ARM::LDRH_POST:
1386     case ARM::LDRSH:
1387     case ARM::LDRSH_PRE:
1388     case ARM::LDRSH_POST:
1389     case ARM::LDRSB:
1390     case ARM::LDRSB_PRE:
1391     case ARM::LDRSB_POST:
1392     case ARM::LDRHTr:
1393     case ARM::LDRSBTr:
1394       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1395         return MCDisassembler::Fail;
1396       break;
1397     default:
1398       break;
1399     }
1400   }
1401 
1402   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1403     return MCDisassembler::Fail;
1404 
1405   if (type) {
1406     Inst.addOperand(MCOperand::CreateReg(0));
1407     Inst.addOperand(MCOperand::CreateImm(U | (imm << 4) | Rm));
1408   } else {
1409     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1410     return MCDisassembler::Fail;
1411     Inst.addOperand(MCOperand::CreateImm(U));
1412   }
1413 
1414   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1415     return MCDisassembler::Fail;
1416 
1417   return S;
1418 }
1419 
1420 static DecodeStatus DecodeRFEInstruction(llvm::MCInst &Inst, unsigned Insn,
1421                                  uint64_t Address, const void *Decoder) {
1422   DecodeStatus S = MCDisassembler::Success;
1423 
1424   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1425   unsigned mode = fieldFromInstruction32(Insn, 23, 2);
1426 
1427   switch (mode) {
1428     case 0:
1429       mode = ARM_AM::da;
1430       break;
1431     case 1:
1432       mode = ARM_AM::ia;
1433       break;
1434     case 2:
1435       mode = ARM_AM::db;
1436       break;
1437     case 3:
1438       mode = ARM_AM::ib;
1439       break;
1440   }
1441 
1442   Inst.addOperand(MCOperand::CreateImm(mode));
1443   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1444     return MCDisassembler::Fail;
1445 
1446   return S;
1447 }
1448 
1449 static DecodeStatus DecodeMemMultipleWritebackInstruction(llvm::MCInst &Inst,
1450                                   unsigned Insn,
1451                                   uint64_t Address, const void *Decoder) {
1452   DecodeStatus S = MCDisassembler::Success;
1453 
1454   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1455   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1456   unsigned reglist = fieldFromInstruction32(Insn, 0, 16);
1457 
1458   if (pred == 0xF) {
1459     switch (Inst.getOpcode()) {
1460       case ARM::LDMDA:
1461         Inst.setOpcode(ARM::RFEDA);
1462         break;
1463       case ARM::LDMDA_UPD:
1464         Inst.setOpcode(ARM::RFEDA_UPD);
1465         break;
1466       case ARM::LDMDB:
1467         Inst.setOpcode(ARM::RFEDB);
1468         break;
1469       case ARM::LDMDB_UPD:
1470         Inst.setOpcode(ARM::RFEDB_UPD);
1471         break;
1472       case ARM::LDMIA:
1473         Inst.setOpcode(ARM::RFEIA);
1474         break;
1475       case ARM::LDMIA_UPD:
1476         Inst.setOpcode(ARM::RFEIA_UPD);
1477         break;
1478       case ARM::LDMIB:
1479         Inst.setOpcode(ARM::RFEIB);
1480         break;
1481       case ARM::LDMIB_UPD:
1482         Inst.setOpcode(ARM::RFEIB_UPD);
1483         break;
1484       case ARM::STMDA:
1485         Inst.setOpcode(ARM::SRSDA);
1486         break;
1487       case ARM::STMDA_UPD:
1488         Inst.setOpcode(ARM::SRSDA_UPD);
1489         break;
1490       case ARM::STMDB:
1491         Inst.setOpcode(ARM::SRSDB);
1492         break;
1493       case ARM::STMDB_UPD:
1494         Inst.setOpcode(ARM::SRSDB_UPD);
1495         break;
1496       case ARM::STMIA:
1497         Inst.setOpcode(ARM::SRSIA);
1498         break;
1499       case ARM::STMIA_UPD:
1500         Inst.setOpcode(ARM::SRSIA_UPD);
1501         break;
1502       case ARM::STMIB:
1503         Inst.setOpcode(ARM::SRSIB);
1504         break;
1505       case ARM::STMIB_UPD:
1506         Inst.setOpcode(ARM::SRSIB_UPD);
1507         break;
1508       default:
1509         if (!Check(S, MCDisassembler::Fail)) return MCDisassembler::Fail;
1510     }
1511 
1512     // For stores (which become SRS's, the only operand is the mode.
1513     if (fieldFromInstruction32(Insn, 20, 1) == 0) {
1514       Inst.addOperand(
1515           MCOperand::CreateImm(fieldFromInstruction32(Insn, 0, 4)));
1516       return S;
1517     }
1518 
1519     return DecodeRFEInstruction(Inst, Insn, Address, Decoder);
1520   }
1521 
1522   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1523     return MCDisassembler::Fail;
1524   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1525     return MCDisassembler::Fail; // Tied
1526   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1527     return MCDisassembler::Fail;
1528   if (!Check(S, DecodeRegListOperand(Inst, reglist, Address, Decoder)))
1529     return MCDisassembler::Fail;
1530 
1531   return S;
1532 }
1533 
1534 static DecodeStatus DecodeCPSInstruction(llvm::MCInst &Inst, unsigned Insn,
1535                                  uint64_t Address, const void *Decoder) {
1536   unsigned imod = fieldFromInstruction32(Insn, 18, 2);
1537   unsigned M = fieldFromInstruction32(Insn, 17, 1);
1538   unsigned iflags = fieldFromInstruction32(Insn, 6, 3);
1539   unsigned mode = fieldFromInstruction32(Insn, 0, 5);
1540 
1541   DecodeStatus S = MCDisassembler::Success;
1542 
1543   // imod == '01' --> UNPREDICTABLE
1544   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
1545   // return failure here.  The '01' imod value is unprintable, so there's
1546   // nothing useful we could do even if we returned UNPREDICTABLE.
1547 
1548   if (imod == 1) return MCDisassembler::Fail;
1549 
1550   if (imod && M) {
1551     Inst.setOpcode(ARM::CPS3p);
1552     Inst.addOperand(MCOperand::CreateImm(imod));
1553     Inst.addOperand(MCOperand::CreateImm(iflags));
1554     Inst.addOperand(MCOperand::CreateImm(mode));
1555   } else if (imod && !M) {
1556     Inst.setOpcode(ARM::CPS2p);
1557     Inst.addOperand(MCOperand::CreateImm(imod));
1558     Inst.addOperand(MCOperand::CreateImm(iflags));
1559     if (mode) S = MCDisassembler::SoftFail;
1560   } else if (!imod && M) {
1561     Inst.setOpcode(ARM::CPS1p);
1562     Inst.addOperand(MCOperand::CreateImm(mode));
1563     if (iflags) S = MCDisassembler::SoftFail;
1564   } else {
1565     // imod == '00' && M == '0' --> UNPREDICTABLE
1566     Inst.setOpcode(ARM::CPS1p);
1567     Inst.addOperand(MCOperand::CreateImm(mode));
1568     S = MCDisassembler::SoftFail;
1569   }
1570 
1571   return S;
1572 }
1573 
1574 static DecodeStatus DecodeT2CPSInstruction(llvm::MCInst &Inst, unsigned Insn,
1575                                  uint64_t Address, const void *Decoder) {
1576   unsigned imod = fieldFromInstruction32(Insn, 9, 2);
1577   unsigned M = fieldFromInstruction32(Insn, 8, 1);
1578   unsigned iflags = fieldFromInstruction32(Insn, 5, 3);
1579   unsigned mode = fieldFromInstruction32(Insn, 0, 5);
1580 
1581   DecodeStatus S = MCDisassembler::Success;
1582 
1583   // imod == '01' --> UNPREDICTABLE
1584   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
1585   // return failure here.  The '01' imod value is unprintable, so there's
1586   // nothing useful we could do even if we returned UNPREDICTABLE.
1587 
1588   if (imod == 1) return MCDisassembler::Fail;
1589 
1590   if (imod && M) {
1591     Inst.setOpcode(ARM::t2CPS3p);
1592     Inst.addOperand(MCOperand::CreateImm(imod));
1593     Inst.addOperand(MCOperand::CreateImm(iflags));
1594     Inst.addOperand(MCOperand::CreateImm(mode));
1595   } else if (imod && !M) {
1596     Inst.setOpcode(ARM::t2CPS2p);
1597     Inst.addOperand(MCOperand::CreateImm(imod));
1598     Inst.addOperand(MCOperand::CreateImm(iflags));
1599     if (mode) S = MCDisassembler::SoftFail;
1600   } else if (!imod && M) {
1601     Inst.setOpcode(ARM::t2CPS1p);
1602     Inst.addOperand(MCOperand::CreateImm(mode));
1603     if (iflags) S = MCDisassembler::SoftFail;
1604   } else {
1605     // imod == '00' && M == '0' --> UNPREDICTABLE
1606     Inst.setOpcode(ARM::t2CPS1p);
1607     Inst.addOperand(MCOperand::CreateImm(mode));
1608     S = MCDisassembler::SoftFail;
1609   }
1610 
1611   return S;
1612 }
1613 
1614 
1615 static DecodeStatus DecodeSMLAInstruction(llvm::MCInst &Inst, unsigned Insn,
1616                                  uint64_t Address, const void *Decoder) {
1617   DecodeStatus S = MCDisassembler::Success;
1618 
1619   unsigned Rd = fieldFromInstruction32(Insn, 16, 4);
1620   unsigned Rn = fieldFromInstruction32(Insn, 0, 4);
1621   unsigned Rm = fieldFromInstruction32(Insn, 8, 4);
1622   unsigned Ra = fieldFromInstruction32(Insn, 12, 4);
1623   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1624 
1625   if (pred == 0xF)
1626     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
1627 
1628   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
1629     return MCDisassembler::Fail;
1630   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
1631     return MCDisassembler::Fail;
1632   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1633     return MCDisassembler::Fail;
1634   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Ra, Address, Decoder)))
1635     return MCDisassembler::Fail;
1636 
1637   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1638     return MCDisassembler::Fail;
1639 
1640   return S;
1641 }
1642 
1643 static DecodeStatus DecodeAddrModeImm12Operand(llvm::MCInst &Inst, unsigned Val,
1644                            uint64_t Address, const void *Decoder) {
1645   DecodeStatus S = MCDisassembler::Success;
1646 
1647   unsigned add = fieldFromInstruction32(Val, 12, 1);
1648   unsigned imm = fieldFromInstruction32(Val, 0, 12);
1649   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
1650 
1651   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1652     return MCDisassembler::Fail;
1653 
1654   if (!add) imm *= -1;
1655   if (imm == 0 && !add) imm = INT32_MIN;
1656   Inst.addOperand(MCOperand::CreateImm(imm));
1657 
1658   return S;
1659 }
1660 
1661 static DecodeStatus DecodeAddrMode5Operand(llvm::MCInst &Inst, unsigned Val,
1662                                    uint64_t Address, const void *Decoder) {
1663   DecodeStatus S = MCDisassembler::Success;
1664 
1665   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
1666   unsigned U = fieldFromInstruction32(Val, 8, 1);
1667   unsigned imm = fieldFromInstruction32(Val, 0, 8);
1668 
1669   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1670     return MCDisassembler::Fail;
1671 
1672   if (U)
1673     Inst.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(ARM_AM::add, imm)));
1674   else
1675     Inst.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(ARM_AM::sub, imm)));
1676 
1677   return S;
1678 }
1679 
1680 static DecodeStatus DecodeAddrMode7Operand(llvm::MCInst &Inst, unsigned Val,
1681                                    uint64_t Address, const void *Decoder) {
1682   return DecodeGPRRegisterClass(Inst, Val, Address, Decoder);
1683 }
1684 
1685 static DecodeStatus
1686 DecodeBranchImmInstruction(llvm::MCInst &Inst, unsigned Insn,
1687                            uint64_t Address, const void *Decoder) {
1688   DecodeStatus S = MCDisassembler::Success;
1689 
1690   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1691   unsigned imm = fieldFromInstruction32(Insn, 0, 24) << 2;
1692 
1693   if (pred == 0xF) {
1694     Inst.setOpcode(ARM::BLXi);
1695     imm |= fieldFromInstruction32(Insn, 24, 1) << 1;
1696     Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(imm)));
1697     return S;
1698   }
1699 
1700   Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(imm)));
1701   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1702     return MCDisassembler::Fail;
1703 
1704   return S;
1705 }
1706 
1707 
1708 static DecodeStatus DecodeVCVTImmOperand(llvm::MCInst &Inst, unsigned Val,
1709                                  uint64_t Address, const void *Decoder) {
1710   Inst.addOperand(MCOperand::CreateImm(64 - Val));
1711   return MCDisassembler::Success;
1712 }
1713 
1714 static DecodeStatus DecodeAddrMode6Operand(llvm::MCInst &Inst, unsigned Val,
1715                                    uint64_t Address, const void *Decoder) {
1716   DecodeStatus S = MCDisassembler::Success;
1717 
1718   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
1719   unsigned align = fieldFromInstruction32(Val, 4, 2);
1720 
1721   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1722     return MCDisassembler::Fail;
1723   if (!align)
1724     Inst.addOperand(MCOperand::CreateImm(0));
1725   else
1726     Inst.addOperand(MCOperand::CreateImm(4 << align));
1727 
1728   return S;
1729 }
1730 
1731 static DecodeStatus DecodeVLDInstruction(llvm::MCInst &Inst, unsigned Insn,
1732                                    uint64_t Address, const void *Decoder) {
1733   DecodeStatus S = MCDisassembler::Success;
1734 
1735   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
1736   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
1737   unsigned wb = fieldFromInstruction32(Insn, 16, 4);
1738   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1739   Rn |= fieldFromInstruction32(Insn, 4, 2) << 4;
1740   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1741 
1742   // First output register
1743   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
1744     return MCDisassembler::Fail;
1745 
1746   // Second output register
1747   switch (Inst.getOpcode()) {
1748     case ARM::VLD1q8:
1749     case ARM::VLD1q16:
1750     case ARM::VLD1q32:
1751     case ARM::VLD1q64:
1752     case ARM::VLD1q8_UPD:
1753     case ARM::VLD1q16_UPD:
1754     case ARM::VLD1q32_UPD:
1755     case ARM::VLD1q64_UPD:
1756     case ARM::VLD1d8T:
1757     case ARM::VLD1d16T:
1758     case ARM::VLD1d32T:
1759     case ARM::VLD1d64T:
1760     case ARM::VLD1d8T_UPD:
1761     case ARM::VLD1d16T_UPD:
1762     case ARM::VLD1d32T_UPD:
1763     case ARM::VLD1d64T_UPD:
1764     case ARM::VLD1d8Q:
1765     case ARM::VLD1d16Q:
1766     case ARM::VLD1d32Q:
1767     case ARM::VLD1d64Q:
1768     case ARM::VLD1d8Q_UPD:
1769     case ARM::VLD1d16Q_UPD:
1770     case ARM::VLD1d32Q_UPD:
1771     case ARM::VLD1d64Q_UPD:
1772     case ARM::VLD2d8:
1773     case ARM::VLD2d16:
1774     case ARM::VLD2d32:
1775     case ARM::VLD2d8_UPD:
1776     case ARM::VLD2d16_UPD:
1777     case ARM::VLD2d32_UPD:
1778     case ARM::VLD2q8:
1779     case ARM::VLD2q16:
1780     case ARM::VLD2q32:
1781     case ARM::VLD2q8_UPD:
1782     case ARM::VLD2q16_UPD:
1783     case ARM::VLD2q32_UPD:
1784     case ARM::VLD3d8:
1785     case ARM::VLD3d16:
1786     case ARM::VLD3d32:
1787     case ARM::VLD3d8_UPD:
1788     case ARM::VLD3d16_UPD:
1789     case ARM::VLD3d32_UPD:
1790     case ARM::VLD4d8:
1791     case ARM::VLD4d16:
1792     case ARM::VLD4d32:
1793     case ARM::VLD4d8_UPD:
1794     case ARM::VLD4d16_UPD:
1795     case ARM::VLD4d32_UPD:
1796       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
1797         return MCDisassembler::Fail;
1798       break;
1799     case ARM::VLD2b8:
1800     case ARM::VLD2b16:
1801     case ARM::VLD2b32:
1802     case ARM::VLD2b8_UPD:
1803     case ARM::VLD2b16_UPD:
1804     case ARM::VLD2b32_UPD:
1805     case ARM::VLD3q8:
1806     case ARM::VLD3q16:
1807     case ARM::VLD3q32:
1808     case ARM::VLD3q8_UPD:
1809     case ARM::VLD3q16_UPD:
1810     case ARM::VLD3q32_UPD:
1811     case ARM::VLD4q8:
1812     case ARM::VLD4q16:
1813     case ARM::VLD4q32:
1814     case ARM::VLD4q8_UPD:
1815     case ARM::VLD4q16_UPD:
1816     case ARM::VLD4q32_UPD:
1817       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
1818         return MCDisassembler::Fail;
1819     default:
1820       break;
1821   }
1822 
1823   // Third output register
1824   switch(Inst.getOpcode()) {
1825     case ARM::VLD1d8T:
1826     case ARM::VLD1d16T:
1827     case ARM::VLD1d32T:
1828     case ARM::VLD1d64T:
1829     case ARM::VLD1d8T_UPD:
1830     case ARM::VLD1d16T_UPD:
1831     case ARM::VLD1d32T_UPD:
1832     case ARM::VLD1d64T_UPD:
1833     case ARM::VLD1d8Q:
1834     case ARM::VLD1d16Q:
1835     case ARM::VLD1d32Q:
1836     case ARM::VLD1d64Q:
1837     case ARM::VLD1d8Q_UPD:
1838     case ARM::VLD1d16Q_UPD:
1839     case ARM::VLD1d32Q_UPD:
1840     case ARM::VLD1d64Q_UPD:
1841     case ARM::VLD2q8:
1842     case ARM::VLD2q16:
1843     case ARM::VLD2q32:
1844     case ARM::VLD2q8_UPD:
1845     case ARM::VLD2q16_UPD:
1846     case ARM::VLD2q32_UPD:
1847     case ARM::VLD3d8:
1848     case ARM::VLD3d16:
1849     case ARM::VLD3d32:
1850     case ARM::VLD3d8_UPD:
1851     case ARM::VLD3d16_UPD:
1852     case ARM::VLD3d32_UPD:
1853     case ARM::VLD4d8:
1854     case ARM::VLD4d16:
1855     case ARM::VLD4d32:
1856     case ARM::VLD4d8_UPD:
1857     case ARM::VLD4d16_UPD:
1858     case ARM::VLD4d32_UPD:
1859       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
1860         return MCDisassembler::Fail;
1861       break;
1862     case ARM::VLD3q8:
1863     case ARM::VLD3q16:
1864     case ARM::VLD3q32:
1865     case ARM::VLD3q8_UPD:
1866     case ARM::VLD3q16_UPD:
1867     case ARM::VLD3q32_UPD:
1868     case ARM::VLD4q8:
1869     case ARM::VLD4q16:
1870     case ARM::VLD4q32:
1871     case ARM::VLD4q8_UPD:
1872     case ARM::VLD4q16_UPD:
1873     case ARM::VLD4q32_UPD:
1874       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
1875         return MCDisassembler::Fail;
1876       break;
1877     default:
1878       break;
1879   }
1880 
1881   // Fourth output register
1882   switch (Inst.getOpcode()) {
1883     case ARM::VLD1d8Q:
1884     case ARM::VLD1d16Q:
1885     case ARM::VLD1d32Q:
1886     case ARM::VLD1d64Q:
1887     case ARM::VLD1d8Q_UPD:
1888     case ARM::VLD1d16Q_UPD:
1889     case ARM::VLD1d32Q_UPD:
1890     case ARM::VLD1d64Q_UPD:
1891     case ARM::VLD2q8:
1892     case ARM::VLD2q16:
1893     case ARM::VLD2q32:
1894     case ARM::VLD2q8_UPD:
1895     case ARM::VLD2q16_UPD:
1896     case ARM::VLD2q32_UPD:
1897     case ARM::VLD4d8:
1898     case ARM::VLD4d16:
1899     case ARM::VLD4d32:
1900     case ARM::VLD4d8_UPD:
1901     case ARM::VLD4d16_UPD:
1902     case ARM::VLD4d32_UPD:
1903       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
1904         return MCDisassembler::Fail;
1905       break;
1906     case ARM::VLD4q8:
1907     case ARM::VLD4q16:
1908     case ARM::VLD4q32:
1909     case ARM::VLD4q8_UPD:
1910     case ARM::VLD4q16_UPD:
1911     case ARM::VLD4q32_UPD:
1912       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
1913         return MCDisassembler::Fail;
1914       break;
1915     default:
1916       break;
1917   }
1918 
1919   // Writeback operand
1920   switch (Inst.getOpcode()) {
1921     case ARM::VLD1d8_UPD:
1922     case ARM::VLD1d16_UPD:
1923     case ARM::VLD1d32_UPD:
1924     case ARM::VLD1d64_UPD:
1925     case ARM::VLD1q8_UPD:
1926     case ARM::VLD1q16_UPD:
1927     case ARM::VLD1q32_UPD:
1928     case ARM::VLD1q64_UPD:
1929     case ARM::VLD1d8T_UPD:
1930     case ARM::VLD1d16T_UPD:
1931     case ARM::VLD1d32T_UPD:
1932     case ARM::VLD1d64T_UPD:
1933     case ARM::VLD1d8Q_UPD:
1934     case ARM::VLD1d16Q_UPD:
1935     case ARM::VLD1d32Q_UPD:
1936     case ARM::VLD1d64Q_UPD:
1937     case ARM::VLD2d8_UPD:
1938     case ARM::VLD2d16_UPD:
1939     case ARM::VLD2d32_UPD:
1940     case ARM::VLD2q8_UPD:
1941     case ARM::VLD2q16_UPD:
1942     case ARM::VLD2q32_UPD:
1943     case ARM::VLD2b8_UPD:
1944     case ARM::VLD2b16_UPD:
1945     case ARM::VLD2b32_UPD:
1946     case ARM::VLD3d8_UPD:
1947     case ARM::VLD3d16_UPD:
1948     case ARM::VLD3d32_UPD:
1949     case ARM::VLD3q8_UPD:
1950     case ARM::VLD3q16_UPD:
1951     case ARM::VLD3q32_UPD:
1952     case ARM::VLD4d8_UPD:
1953     case ARM::VLD4d16_UPD:
1954     case ARM::VLD4d32_UPD:
1955     case ARM::VLD4q8_UPD:
1956     case ARM::VLD4q16_UPD:
1957     case ARM::VLD4q32_UPD:
1958       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
1959         return MCDisassembler::Fail;
1960       break;
1961     default:
1962       break;
1963   }
1964 
1965   // AddrMode6 Base (register+alignment)
1966   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
1967     return MCDisassembler::Fail;
1968 
1969   // AddrMode6 Offset (register)
1970   if (Rm == 0xD)
1971     Inst.addOperand(MCOperand::CreateReg(0));
1972   else if (Rm != 0xF) {
1973     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1974       return MCDisassembler::Fail;
1975   }
1976 
1977   return S;
1978 }
1979 
1980 static DecodeStatus DecodeVSTInstruction(llvm::MCInst &Inst, unsigned Insn,
1981                                  uint64_t Address, const void *Decoder) {
1982   DecodeStatus S = MCDisassembler::Success;
1983 
1984   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
1985   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
1986   unsigned wb = fieldFromInstruction32(Insn, 16, 4);
1987   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1988   Rn |= fieldFromInstruction32(Insn, 4, 2) << 4;
1989   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1990 
1991   // Writeback Operand
1992   switch (Inst.getOpcode()) {
1993     case ARM::VST1d8_UPD:
1994     case ARM::VST1d16_UPD:
1995     case ARM::VST1d32_UPD:
1996     case ARM::VST1d64_UPD:
1997     case ARM::VST1q8_UPD:
1998     case ARM::VST1q16_UPD:
1999     case ARM::VST1q32_UPD:
2000     case ARM::VST1q64_UPD:
2001     case ARM::VST1d8T_UPD:
2002     case ARM::VST1d16T_UPD:
2003     case ARM::VST1d32T_UPD:
2004     case ARM::VST1d64T_UPD:
2005     case ARM::VST1d8Q_UPD:
2006     case ARM::VST1d16Q_UPD:
2007     case ARM::VST1d32Q_UPD:
2008     case ARM::VST1d64Q_UPD:
2009     case ARM::VST2d8_UPD:
2010     case ARM::VST2d16_UPD:
2011     case ARM::VST2d32_UPD:
2012     case ARM::VST2q8_UPD:
2013     case ARM::VST2q16_UPD:
2014     case ARM::VST2q32_UPD:
2015     case ARM::VST2b8_UPD:
2016     case ARM::VST2b16_UPD:
2017     case ARM::VST2b32_UPD:
2018     case ARM::VST3d8_UPD:
2019     case ARM::VST3d16_UPD:
2020     case ARM::VST3d32_UPD:
2021     case ARM::VST3q8_UPD:
2022     case ARM::VST3q16_UPD:
2023     case ARM::VST3q32_UPD:
2024     case ARM::VST4d8_UPD:
2025     case ARM::VST4d16_UPD:
2026     case ARM::VST4d32_UPD:
2027     case ARM::VST4q8_UPD:
2028     case ARM::VST4q16_UPD:
2029     case ARM::VST4q32_UPD:
2030       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
2031         return MCDisassembler::Fail;
2032       break;
2033     default:
2034       break;
2035   }
2036 
2037   // AddrMode6 Base (register+alignment)
2038   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
2039     return MCDisassembler::Fail;
2040 
2041   // AddrMode6 Offset (register)
2042   if (Rm == 0xD)
2043     Inst.addOperand(MCOperand::CreateReg(0));
2044   else if (Rm != 0xF) {
2045     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2046     return MCDisassembler::Fail;
2047   }
2048 
2049   // First input register
2050   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2051     return MCDisassembler::Fail;
2052 
2053   // Second input register
2054   switch (Inst.getOpcode()) {
2055     case ARM::VST1q8:
2056     case ARM::VST1q16:
2057     case ARM::VST1q32:
2058     case ARM::VST1q64:
2059     case ARM::VST1q8_UPD:
2060     case ARM::VST1q16_UPD:
2061     case ARM::VST1q32_UPD:
2062     case ARM::VST1q64_UPD:
2063     case ARM::VST1d8T:
2064     case ARM::VST1d16T:
2065     case ARM::VST1d32T:
2066     case ARM::VST1d64T:
2067     case ARM::VST1d8T_UPD:
2068     case ARM::VST1d16T_UPD:
2069     case ARM::VST1d32T_UPD:
2070     case ARM::VST1d64T_UPD:
2071     case ARM::VST1d8Q:
2072     case ARM::VST1d16Q:
2073     case ARM::VST1d32Q:
2074     case ARM::VST1d64Q:
2075     case ARM::VST1d8Q_UPD:
2076     case ARM::VST1d16Q_UPD:
2077     case ARM::VST1d32Q_UPD:
2078     case ARM::VST1d64Q_UPD:
2079     case ARM::VST2d8:
2080     case ARM::VST2d16:
2081     case ARM::VST2d32:
2082     case ARM::VST2d8_UPD:
2083     case ARM::VST2d16_UPD:
2084     case ARM::VST2d32_UPD:
2085     case ARM::VST2q8:
2086     case ARM::VST2q16:
2087     case ARM::VST2q32:
2088     case ARM::VST2q8_UPD:
2089     case ARM::VST2q16_UPD:
2090     case ARM::VST2q32_UPD:
2091     case ARM::VST3d8:
2092     case ARM::VST3d16:
2093     case ARM::VST3d32:
2094     case ARM::VST3d8_UPD:
2095     case ARM::VST3d16_UPD:
2096     case ARM::VST3d32_UPD:
2097     case ARM::VST4d8:
2098     case ARM::VST4d16:
2099     case ARM::VST4d32:
2100     case ARM::VST4d8_UPD:
2101     case ARM::VST4d16_UPD:
2102     case ARM::VST4d32_UPD:
2103       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
2104         return MCDisassembler::Fail;
2105       break;
2106     case ARM::VST2b8:
2107     case ARM::VST2b16:
2108     case ARM::VST2b32:
2109     case ARM::VST2b8_UPD:
2110     case ARM::VST2b16_UPD:
2111     case ARM::VST2b32_UPD:
2112     case ARM::VST3q8:
2113     case ARM::VST3q16:
2114     case ARM::VST3q32:
2115     case ARM::VST3q8_UPD:
2116     case ARM::VST3q16_UPD:
2117     case ARM::VST3q32_UPD:
2118     case ARM::VST4q8:
2119     case ARM::VST4q16:
2120     case ARM::VST4q32:
2121     case ARM::VST4q8_UPD:
2122     case ARM::VST4q16_UPD:
2123     case ARM::VST4q32_UPD:
2124       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2125         return MCDisassembler::Fail;
2126       break;
2127     default:
2128       break;
2129   }
2130 
2131   // Third input register
2132   switch (Inst.getOpcode()) {
2133     case ARM::VST1d8T:
2134     case ARM::VST1d16T:
2135     case ARM::VST1d32T:
2136     case ARM::VST1d64T:
2137     case ARM::VST1d8T_UPD:
2138     case ARM::VST1d16T_UPD:
2139     case ARM::VST1d32T_UPD:
2140     case ARM::VST1d64T_UPD:
2141     case ARM::VST1d8Q:
2142     case ARM::VST1d16Q:
2143     case ARM::VST1d32Q:
2144     case ARM::VST1d64Q:
2145     case ARM::VST1d8Q_UPD:
2146     case ARM::VST1d16Q_UPD:
2147     case ARM::VST1d32Q_UPD:
2148     case ARM::VST1d64Q_UPD:
2149     case ARM::VST2q8:
2150     case ARM::VST2q16:
2151     case ARM::VST2q32:
2152     case ARM::VST2q8_UPD:
2153     case ARM::VST2q16_UPD:
2154     case ARM::VST2q32_UPD:
2155     case ARM::VST3d8:
2156     case ARM::VST3d16:
2157     case ARM::VST3d32:
2158     case ARM::VST3d8_UPD:
2159     case ARM::VST3d16_UPD:
2160     case ARM::VST3d32_UPD:
2161     case ARM::VST4d8:
2162     case ARM::VST4d16:
2163     case ARM::VST4d32:
2164     case ARM::VST4d8_UPD:
2165     case ARM::VST4d16_UPD:
2166     case ARM::VST4d32_UPD:
2167       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2168         return MCDisassembler::Fail;
2169       break;
2170     case ARM::VST3q8:
2171     case ARM::VST3q16:
2172     case ARM::VST3q32:
2173     case ARM::VST3q8_UPD:
2174     case ARM::VST3q16_UPD:
2175     case ARM::VST3q32_UPD:
2176     case ARM::VST4q8:
2177     case ARM::VST4q16:
2178     case ARM::VST4q32:
2179     case ARM::VST4q8_UPD:
2180     case ARM::VST4q16_UPD:
2181     case ARM::VST4q32_UPD:
2182       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
2183         return MCDisassembler::Fail;
2184       break;
2185     default:
2186       break;
2187   }
2188 
2189   // Fourth input register
2190   switch (Inst.getOpcode()) {
2191     case ARM::VST1d8Q:
2192     case ARM::VST1d16Q:
2193     case ARM::VST1d32Q:
2194     case ARM::VST1d64Q:
2195     case ARM::VST1d8Q_UPD:
2196     case ARM::VST1d16Q_UPD:
2197     case ARM::VST1d32Q_UPD:
2198     case ARM::VST1d64Q_UPD:
2199     case ARM::VST2q8:
2200     case ARM::VST2q16:
2201     case ARM::VST2q32:
2202     case ARM::VST2q8_UPD:
2203     case ARM::VST2q16_UPD:
2204     case ARM::VST2q32_UPD:
2205     case ARM::VST4d8:
2206     case ARM::VST4d16:
2207     case ARM::VST4d32:
2208     case ARM::VST4d8_UPD:
2209     case ARM::VST4d16_UPD:
2210     case ARM::VST4d32_UPD:
2211       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
2212         return MCDisassembler::Fail;
2213       break;
2214     case ARM::VST4q8:
2215     case ARM::VST4q16:
2216     case ARM::VST4q32:
2217     case ARM::VST4q8_UPD:
2218     case ARM::VST4q16_UPD:
2219     case ARM::VST4q32_UPD:
2220       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
2221         return MCDisassembler::Fail;
2222       break;
2223     default:
2224       break;
2225   }
2226 
2227   return S;
2228 }
2229 
2230 static DecodeStatus DecodeVLD1DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2231                                     uint64_t Address, const void *Decoder) {
2232   DecodeStatus S = MCDisassembler::Success;
2233 
2234   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2235   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2236   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2237   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2238   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2239   unsigned size = fieldFromInstruction32(Insn, 6, 2);
2240   unsigned regs = fieldFromInstruction32(Insn, 5, 1) + 1;
2241 
2242   align *= (1 << size);
2243 
2244   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2245     return MCDisassembler::Fail;
2246   if (regs == 2) {
2247     if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
2248       return MCDisassembler::Fail;
2249   }
2250   if (Rm != 0xF) {
2251     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2252       return MCDisassembler::Fail;
2253   }
2254 
2255   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2256     return MCDisassembler::Fail;
2257   Inst.addOperand(MCOperand::CreateImm(align));
2258 
2259   if (Rm == 0xD)
2260     Inst.addOperand(MCOperand::CreateReg(0));
2261   else if (Rm != 0xF) {
2262     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2263       return MCDisassembler::Fail;
2264   }
2265 
2266   return S;
2267 }
2268 
2269 static DecodeStatus DecodeVLD2DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2270                                     uint64_t Address, const void *Decoder) {
2271   DecodeStatus S = MCDisassembler::Success;
2272 
2273   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2274   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2275   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2276   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2277   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2278   unsigned size = 1 << fieldFromInstruction32(Insn, 6, 2);
2279   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2280   align *= 2*size;
2281 
2282   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2283     return MCDisassembler::Fail;
2284   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
2285     return MCDisassembler::Fail;
2286   if (Rm != 0xF) {
2287     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2288       return MCDisassembler::Fail;
2289   }
2290 
2291   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2292     return MCDisassembler::Fail;
2293   Inst.addOperand(MCOperand::CreateImm(align));
2294 
2295   if (Rm == 0xD)
2296     Inst.addOperand(MCOperand::CreateReg(0));
2297   else if (Rm != 0xF) {
2298     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2299       return MCDisassembler::Fail;
2300   }
2301 
2302   return S;
2303 }
2304 
2305 static DecodeStatus DecodeVLD3DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2306                                     uint64_t Address, const void *Decoder) {
2307   DecodeStatus S = MCDisassembler::Success;
2308 
2309   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2310   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2311   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2312   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2313   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2314 
2315   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2316     return MCDisassembler::Fail;
2317   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
2318     return MCDisassembler::Fail;
2319   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
2320     return MCDisassembler::Fail;
2321   if (Rm != 0xF) {
2322     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2323       return MCDisassembler::Fail;
2324   }
2325 
2326   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2327     return MCDisassembler::Fail;
2328   Inst.addOperand(MCOperand::CreateImm(0));
2329 
2330   if (Rm == 0xD)
2331     Inst.addOperand(MCOperand::CreateReg(0));
2332   else if (Rm != 0xF) {
2333     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2334       return MCDisassembler::Fail;
2335   }
2336 
2337   return S;
2338 }
2339 
2340 static DecodeStatus DecodeVLD4DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2341                                     uint64_t Address, const void *Decoder) {
2342   DecodeStatus S = MCDisassembler::Success;
2343 
2344   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2345   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2346   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2347   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2348   unsigned size = fieldFromInstruction32(Insn, 6, 2);
2349   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2350   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2351 
2352   if (size == 0x3) {
2353     size = 4;
2354     align = 16;
2355   } else {
2356     if (size == 2) {
2357       size = 1 << size;
2358       align *= 8;
2359     } else {
2360       size = 1 << size;
2361       align *= 4*size;
2362     }
2363   }
2364 
2365   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2366     return MCDisassembler::Fail;
2367   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
2368     return MCDisassembler::Fail;
2369   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
2370     return MCDisassembler::Fail;
2371   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3*inc)%32, Address, Decoder)))
2372     return MCDisassembler::Fail;
2373   if (Rm != 0xF) {
2374     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2375       return MCDisassembler::Fail;
2376   }
2377 
2378   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2379     return MCDisassembler::Fail;
2380   Inst.addOperand(MCOperand::CreateImm(align));
2381 
2382   if (Rm == 0xD)
2383     Inst.addOperand(MCOperand::CreateReg(0));
2384   else if (Rm != 0xF) {
2385     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2386       return MCDisassembler::Fail;
2387   }
2388 
2389   return S;
2390 }
2391 
2392 static DecodeStatus
2393 DecodeNEONModImmInstruction(llvm::MCInst &Inst, unsigned Insn,
2394                             uint64_t Address, const void *Decoder) {
2395   DecodeStatus S = MCDisassembler::Success;
2396 
2397   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2398   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2399   unsigned imm = fieldFromInstruction32(Insn, 0, 4);
2400   imm |= fieldFromInstruction32(Insn, 16, 3) << 4;
2401   imm |= fieldFromInstruction32(Insn, 24, 1) << 7;
2402   imm |= fieldFromInstruction32(Insn, 8, 4) << 8;
2403   imm |= fieldFromInstruction32(Insn, 5, 1) << 12;
2404   unsigned Q = fieldFromInstruction32(Insn, 6, 1);
2405 
2406   if (Q) {
2407     if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2408     return MCDisassembler::Fail;
2409   } else {
2410     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2411     return MCDisassembler::Fail;
2412   }
2413 
2414   Inst.addOperand(MCOperand::CreateImm(imm));
2415 
2416   switch (Inst.getOpcode()) {
2417     case ARM::VORRiv4i16:
2418     case ARM::VORRiv2i32:
2419     case ARM::VBICiv4i16:
2420     case ARM::VBICiv2i32:
2421       if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2422         return MCDisassembler::Fail;
2423       break;
2424     case ARM::VORRiv8i16:
2425     case ARM::VORRiv4i32:
2426     case ARM::VBICiv8i16:
2427     case ARM::VBICiv4i32:
2428       if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2429         return MCDisassembler::Fail;
2430       break;
2431     default:
2432       break;
2433   }
2434 
2435   return S;
2436 }
2437 
2438 static DecodeStatus DecodeVSHLMaxInstruction(llvm::MCInst &Inst, unsigned Insn,
2439                                         uint64_t Address, const void *Decoder) {
2440   DecodeStatus S = MCDisassembler::Success;
2441 
2442   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2443   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2444   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2445   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
2446   unsigned size = fieldFromInstruction32(Insn, 18, 2);
2447 
2448   if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2449     return MCDisassembler::Fail;
2450   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
2451     return MCDisassembler::Fail;
2452   Inst.addOperand(MCOperand::CreateImm(8 << size));
2453 
2454   return S;
2455 }
2456 
2457 static DecodeStatus DecodeShiftRight8Imm(llvm::MCInst &Inst, unsigned Val,
2458                                uint64_t Address, const void *Decoder) {
2459   Inst.addOperand(MCOperand::CreateImm(8 - Val));
2460   return MCDisassembler::Success;
2461 }
2462 
2463 static DecodeStatus DecodeShiftRight16Imm(llvm::MCInst &Inst, unsigned Val,
2464                                uint64_t Address, const void *Decoder) {
2465   Inst.addOperand(MCOperand::CreateImm(16 - Val));
2466   return MCDisassembler::Success;
2467 }
2468 
2469 static DecodeStatus DecodeShiftRight32Imm(llvm::MCInst &Inst, unsigned Val,
2470                                uint64_t Address, const void *Decoder) {
2471   Inst.addOperand(MCOperand::CreateImm(32 - Val));
2472   return MCDisassembler::Success;
2473 }
2474 
2475 static DecodeStatus DecodeShiftRight64Imm(llvm::MCInst &Inst, unsigned Val,
2476                                uint64_t Address, const void *Decoder) {
2477   Inst.addOperand(MCOperand::CreateImm(64 - Val));
2478   return MCDisassembler::Success;
2479 }
2480 
2481 static DecodeStatus DecodeTBLInstruction(llvm::MCInst &Inst, unsigned Insn,
2482                                uint64_t Address, const void *Decoder) {
2483   DecodeStatus S = MCDisassembler::Success;
2484 
2485   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2486   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2487   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2488   Rn |= fieldFromInstruction32(Insn, 7, 1) << 4;
2489   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2490   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
2491   unsigned op = fieldFromInstruction32(Insn, 6, 1);
2492   unsigned length = fieldFromInstruction32(Insn, 8, 2) + 1;
2493 
2494   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2495     return MCDisassembler::Fail;
2496   if (op) {
2497     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2498     return MCDisassembler::Fail; // Writeback
2499   }
2500 
2501   for (unsigned i = 0; i < length; ++i) {
2502     if (!Check(S, DecodeDPRRegisterClass(Inst, (Rn+i)%32, Address, Decoder)))
2503     return MCDisassembler::Fail;
2504   }
2505 
2506   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
2507     return MCDisassembler::Fail;
2508 
2509   return S;
2510 }
2511 
2512 static DecodeStatus DecodeVFPfpImm(llvm::MCInst &Inst, unsigned Val,
2513                             uint64_t Address, const void *Decoder) {
2514   // The immediate needs to be a fully instantiated float.  However, the
2515   // auto-generated decoder is only able to fill in some of the bits
2516   // necessary.  For instance, the 'b' bit is replicated multiple times,
2517   // and is even present in inverted form in one bit.  We do a little
2518   // binary parsing here to fill in those missing bits, and then
2519   // reinterpret it all as a float.
2520   union {
2521     uint32_t integer;
2522     float fp;
2523   } fp_conv;
2524 
2525   fp_conv.integer = Val;
2526   uint32_t b = fieldFromInstruction32(Val, 25, 1);
2527   fp_conv.integer |= b << 26;
2528   fp_conv.integer |= b << 27;
2529   fp_conv.integer |= b << 28;
2530   fp_conv.integer |= b << 29;
2531   fp_conv.integer |= (~b & 0x1) << 30;
2532 
2533   Inst.addOperand(MCOperand::CreateFPImm(fp_conv.fp));
2534   return MCDisassembler::Success;
2535 }
2536 
2537 static DecodeStatus DecodeThumbAddSpecialReg(llvm::MCInst &Inst, uint16_t Insn,
2538                                      uint64_t Address, const void *Decoder) {
2539   DecodeStatus S = MCDisassembler::Success;
2540 
2541   unsigned dst = fieldFromInstruction16(Insn, 8, 3);
2542   unsigned imm = fieldFromInstruction16(Insn, 0, 8);
2543 
2544   if (!Check(S, DecodetGPRRegisterClass(Inst, dst, Address, Decoder)))
2545     return MCDisassembler::Fail;
2546 
2547   switch(Inst.getOpcode()) {
2548     default:
2549       return MCDisassembler::Fail;
2550     case ARM::tADR:
2551       break; // tADR does not explicitly represent the PC as an operand.
2552     case ARM::tADDrSPi:
2553       Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2554       break;
2555   }
2556 
2557   Inst.addOperand(MCOperand::CreateImm(imm));
2558   return S;
2559 }
2560 
2561 static DecodeStatus DecodeThumbBROperand(llvm::MCInst &Inst, unsigned Val,
2562                                  uint64_t Address, const void *Decoder) {
2563   Inst.addOperand(MCOperand::CreateImm(SignExtend32<12>(Val << 1)));
2564   return MCDisassembler::Success;
2565 }
2566 
2567 static DecodeStatus DecodeT2BROperand(llvm::MCInst &Inst, unsigned Val,
2568                                  uint64_t Address, const void *Decoder) {
2569   Inst.addOperand(MCOperand::CreateImm(SignExtend32<21>(Val)));
2570   return MCDisassembler::Success;
2571 }
2572 
2573 static DecodeStatus DecodeThumbCmpBROperand(llvm::MCInst &Inst, unsigned Val,
2574                                  uint64_t Address, const void *Decoder) {
2575   Inst.addOperand(MCOperand::CreateImm(SignExtend32<7>(Val << 1)));
2576   return MCDisassembler::Success;
2577 }
2578 
2579 static DecodeStatus DecodeThumbAddrModeRR(llvm::MCInst &Inst, unsigned Val,
2580                                  uint64_t Address, const void *Decoder) {
2581   DecodeStatus S = MCDisassembler::Success;
2582 
2583   unsigned Rn = fieldFromInstruction32(Val, 0, 3);
2584   unsigned Rm = fieldFromInstruction32(Val, 3, 3);
2585 
2586   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
2587     return MCDisassembler::Fail;
2588   if (!Check(S, DecodetGPRRegisterClass(Inst, Rm, Address, Decoder)))
2589     return MCDisassembler::Fail;
2590 
2591   return S;
2592 }
2593 
2594 static DecodeStatus DecodeThumbAddrModeIS(llvm::MCInst &Inst, unsigned Val,
2595                                   uint64_t Address, const void *Decoder) {
2596   DecodeStatus S = MCDisassembler::Success;
2597 
2598   unsigned Rn = fieldFromInstruction32(Val, 0, 3);
2599   unsigned imm = fieldFromInstruction32(Val, 3, 5);
2600 
2601   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
2602     return MCDisassembler::Fail;
2603   Inst.addOperand(MCOperand::CreateImm(imm));
2604 
2605   return S;
2606 }
2607 
2608 static DecodeStatus DecodeThumbAddrModePC(llvm::MCInst &Inst, unsigned Val,
2609                                   uint64_t Address, const void *Decoder) {
2610   Inst.addOperand(MCOperand::CreateImm(Val << 2));
2611 
2612   return MCDisassembler::Success;
2613 }
2614 
2615 static DecodeStatus DecodeThumbAddrModeSP(llvm::MCInst &Inst, unsigned Val,
2616                                   uint64_t Address, const void *Decoder) {
2617   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2618   Inst.addOperand(MCOperand::CreateImm(Val));
2619 
2620   return MCDisassembler::Success;
2621 }
2622 
2623 static DecodeStatus DecodeT2AddrModeSOReg(llvm::MCInst &Inst, unsigned Val,
2624                                   uint64_t Address, const void *Decoder) {
2625   DecodeStatus S = MCDisassembler::Success;
2626 
2627   unsigned Rn = fieldFromInstruction32(Val, 6, 4);
2628   unsigned Rm = fieldFromInstruction32(Val, 2, 4);
2629   unsigned imm = fieldFromInstruction32(Val, 0, 2);
2630 
2631   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2632     return MCDisassembler::Fail;
2633   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
2634     return MCDisassembler::Fail;
2635   Inst.addOperand(MCOperand::CreateImm(imm));
2636 
2637   return S;
2638 }
2639 
2640 static DecodeStatus DecodeT2LoadShift(llvm::MCInst &Inst, unsigned Insn,
2641                               uint64_t Address, const void *Decoder) {
2642   DecodeStatus S = MCDisassembler::Success;
2643 
2644   switch (Inst.getOpcode()) {
2645     case ARM::t2PLDs:
2646     case ARM::t2PLDWs:
2647     case ARM::t2PLIs:
2648       break;
2649     default: {
2650       unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2651       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
2652     return MCDisassembler::Fail;
2653     }
2654   }
2655 
2656   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2657   if (Rn == 0xF) {
2658     switch (Inst.getOpcode()) {
2659       case ARM::t2LDRBs:
2660         Inst.setOpcode(ARM::t2LDRBpci);
2661         break;
2662       case ARM::t2LDRHs:
2663         Inst.setOpcode(ARM::t2LDRHpci);
2664         break;
2665       case ARM::t2LDRSHs:
2666         Inst.setOpcode(ARM::t2LDRSHpci);
2667         break;
2668       case ARM::t2LDRSBs:
2669         Inst.setOpcode(ARM::t2LDRSBpci);
2670         break;
2671       case ARM::t2PLDs:
2672         Inst.setOpcode(ARM::t2PLDi12);
2673         Inst.addOperand(MCOperand::CreateReg(ARM::PC));
2674         break;
2675       default:
2676         return MCDisassembler::Fail;
2677     }
2678 
2679     int imm = fieldFromInstruction32(Insn, 0, 12);
2680     if (!fieldFromInstruction32(Insn, 23, 1)) imm *= -1;
2681     Inst.addOperand(MCOperand::CreateImm(imm));
2682 
2683     return S;
2684   }
2685 
2686   unsigned addrmode = fieldFromInstruction32(Insn, 4, 2);
2687   addrmode |= fieldFromInstruction32(Insn, 0, 4) << 2;
2688   addrmode |= fieldFromInstruction32(Insn, 16, 4) << 6;
2689   if (!Check(S, DecodeT2AddrModeSOReg(Inst, addrmode, Address, Decoder)))
2690     return MCDisassembler::Fail;
2691 
2692   return S;
2693 }
2694 
2695 static DecodeStatus DecodeT2Imm8S4(llvm::MCInst &Inst, unsigned Val,
2696                            uint64_t Address, const void *Decoder) {
2697   int imm = Val & 0xFF;
2698   if (!(Val & 0x100)) imm *= -1;
2699   Inst.addOperand(MCOperand::CreateImm(imm << 2));
2700 
2701   return MCDisassembler::Success;
2702 }
2703 
2704 static DecodeStatus DecodeT2AddrModeImm8s4(llvm::MCInst &Inst, unsigned Val,
2705                                    uint64_t Address, const void *Decoder) {
2706   DecodeStatus S = MCDisassembler::Success;
2707 
2708   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
2709   unsigned imm = fieldFromInstruction32(Val, 0, 9);
2710 
2711   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2712     return MCDisassembler::Fail;
2713   if (!Check(S, DecodeT2Imm8S4(Inst, imm, Address, Decoder)))
2714     return MCDisassembler::Fail;
2715 
2716   return S;
2717 }
2718 
2719 static DecodeStatus DecodeT2AddrModeImm0_1020s4(llvm::MCInst &Inst,unsigned Val,
2720                                    uint64_t Address, const void *Decoder) {
2721   DecodeStatus S = MCDisassembler::Success;
2722 
2723   unsigned Rn = fieldFromInstruction32(Val, 8, 4);
2724   unsigned imm = fieldFromInstruction32(Val, 0, 8);
2725 
2726   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
2727     return MCDisassembler::Fail;
2728 
2729   Inst.addOperand(MCOperand::CreateImm(imm));
2730 
2731   return S;
2732 }
2733 
2734 static DecodeStatus DecodeT2Imm8(llvm::MCInst &Inst, unsigned Val,
2735                          uint64_t Address, const void *Decoder) {
2736   int imm = Val & 0xFF;
2737   if (Val == 0)
2738     imm = INT32_MIN;
2739   else if (!(Val & 0x100))
2740     imm *= -1;
2741   Inst.addOperand(MCOperand::CreateImm(imm));
2742 
2743   return MCDisassembler::Success;
2744 }
2745 
2746 
2747 static DecodeStatus DecodeT2AddrModeImm8(llvm::MCInst &Inst, unsigned Val,
2748                                  uint64_t Address, const void *Decoder) {
2749   DecodeStatus S = MCDisassembler::Success;
2750 
2751   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
2752   unsigned imm = fieldFromInstruction32(Val, 0, 9);
2753 
2754   // Some instructions always use an additive offset.
2755   switch (Inst.getOpcode()) {
2756     case ARM::t2LDRT:
2757     case ARM::t2LDRBT:
2758     case ARM::t2LDRHT:
2759     case ARM::t2LDRSBT:
2760     case ARM::t2LDRSHT:
2761       imm |= 0x100;
2762       break;
2763     default:
2764       break;
2765   }
2766 
2767   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2768     return MCDisassembler::Fail;
2769   if (!Check(S, DecodeT2Imm8(Inst, imm, Address, Decoder)))
2770     return MCDisassembler::Fail;
2771 
2772   return S;
2773 }
2774 
2775 static DecodeStatus DecodeT2LdStPre(llvm::MCInst &Inst, unsigned Insn,
2776                                     uint64_t Address, const void *Decoder) {
2777   DecodeStatus S = MCDisassembler::Success;
2778 
2779   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2780   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2781   unsigned addr = fieldFromInstruction32(Insn, 0, 8);
2782   addr |= fieldFromInstruction32(Insn, 9, 1) << 8;
2783   addr |= Rn << 9;
2784   unsigned load = fieldFromInstruction32(Insn, 20, 1);
2785 
2786   if (!load) {
2787     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2788       return MCDisassembler::Fail;
2789   }
2790 
2791   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
2792     return MCDisassembler::Fail;
2793 
2794   if (load) {
2795     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2796       return MCDisassembler::Fail;
2797   }
2798 
2799   if (!Check(S, DecodeT2AddrModeImm8(Inst, addr, Address, Decoder)))
2800     return MCDisassembler::Fail;
2801 
2802   return S;
2803 }
2804 
2805 static DecodeStatus DecodeT2AddrModeImm12(llvm::MCInst &Inst, unsigned Val,
2806                                   uint64_t Address, const void *Decoder) {
2807   DecodeStatus S = MCDisassembler::Success;
2808 
2809   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
2810   unsigned imm = fieldFromInstruction32(Val, 0, 12);
2811 
2812   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2813     return MCDisassembler::Fail;
2814   Inst.addOperand(MCOperand::CreateImm(imm));
2815 
2816   return S;
2817 }
2818 
2819 
2820 static DecodeStatus DecodeThumbAddSPImm(llvm::MCInst &Inst, uint16_t Insn,
2821                                 uint64_t Address, const void *Decoder) {
2822   unsigned imm = fieldFromInstruction16(Insn, 0, 7);
2823 
2824   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2825   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2826   Inst.addOperand(MCOperand::CreateImm(imm));
2827 
2828   return MCDisassembler::Success;
2829 }
2830 
2831 static DecodeStatus DecodeThumbAddSPReg(llvm::MCInst &Inst, uint16_t Insn,
2832                                 uint64_t Address, const void *Decoder) {
2833   DecodeStatus S = MCDisassembler::Success;
2834 
2835   if (Inst.getOpcode() == ARM::tADDrSP) {
2836     unsigned Rdm = fieldFromInstruction16(Insn, 0, 3);
2837     Rdm |= fieldFromInstruction16(Insn, 7, 1) << 3;
2838 
2839     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
2840     return MCDisassembler::Fail;
2841     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
2842     return MCDisassembler::Fail;
2843     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2844   } else if (Inst.getOpcode() == ARM::tADDspr) {
2845     unsigned Rm = fieldFromInstruction16(Insn, 3, 4);
2846 
2847     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2848     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2849     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2850     return MCDisassembler::Fail;
2851   }
2852 
2853   return S;
2854 }
2855 
2856 static DecodeStatus DecodeThumbCPS(llvm::MCInst &Inst, uint16_t Insn,
2857                            uint64_t Address, const void *Decoder) {
2858   unsigned imod = fieldFromInstruction16(Insn, 4, 1) | 0x2;
2859   unsigned flags = fieldFromInstruction16(Insn, 0, 3);
2860 
2861   Inst.addOperand(MCOperand::CreateImm(imod));
2862   Inst.addOperand(MCOperand::CreateImm(flags));
2863 
2864   return MCDisassembler::Success;
2865 }
2866 
2867 static DecodeStatus DecodePostIdxReg(llvm::MCInst &Inst, unsigned Insn,
2868                              uint64_t Address, const void *Decoder) {
2869   DecodeStatus S = MCDisassembler::Success;
2870   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2871   unsigned add = fieldFromInstruction32(Insn, 4, 1);
2872 
2873   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2874     return MCDisassembler::Fail;
2875   Inst.addOperand(MCOperand::CreateImm(add));
2876 
2877   return S;
2878 }
2879 
2880 static DecodeStatus DecodeThumbBLXOffset(llvm::MCInst &Inst, unsigned Val,
2881                                  uint64_t Address, const void *Decoder) {
2882   Inst.addOperand(MCOperand::CreateImm(SignExtend32<22>(Val << 1)));
2883   return MCDisassembler::Success;
2884 }
2885 
2886 static DecodeStatus DecodeCoprocessor(llvm::MCInst &Inst, unsigned Val,
2887                               uint64_t Address, const void *Decoder) {
2888   if (Val == 0xA || Val == 0xB)
2889     return MCDisassembler::Fail;
2890 
2891   Inst.addOperand(MCOperand::CreateImm(Val));
2892   return MCDisassembler::Success;
2893 }
2894 
2895 static DecodeStatus
2896 DecodeThumb2BCCInstruction(llvm::MCInst &Inst, unsigned Insn,
2897                            uint64_t Address, const void *Decoder) {
2898   DecodeStatus S = MCDisassembler::Success;
2899 
2900   unsigned pred = fieldFromInstruction32(Insn, 22, 4);
2901   if (pred == 0xE || pred == 0xF) {
2902     unsigned opc = fieldFromInstruction32(Insn, 4, 28);
2903     switch (opc) {
2904       default:
2905         return MCDisassembler::Fail;
2906       case 0xf3bf8f4:
2907         Inst.setOpcode(ARM::t2DSB);
2908         break;
2909       case 0xf3bf8f5:
2910         Inst.setOpcode(ARM::t2DMB);
2911         break;
2912       case 0xf3bf8f6:
2913         Inst.setOpcode(ARM::t2ISB);
2914         break;
2915     }
2916 
2917     unsigned imm = fieldFromInstruction32(Insn, 0, 4);
2918     return DecodeMemBarrierOption(Inst, imm, Address, Decoder);
2919   }
2920 
2921   unsigned brtarget = fieldFromInstruction32(Insn, 0, 11) << 1;
2922   brtarget |= fieldFromInstruction32(Insn, 11, 1) << 19;
2923   brtarget |= fieldFromInstruction32(Insn, 13, 1) << 18;
2924   brtarget |= fieldFromInstruction32(Insn, 16, 6) << 12;
2925   brtarget |= fieldFromInstruction32(Insn, 26, 1) << 20;
2926 
2927   if (!Check(S, DecodeT2BROperand(Inst, brtarget, Address, Decoder)))
2928     return MCDisassembler::Fail;
2929   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2930     return MCDisassembler::Fail;
2931 
2932   return S;
2933 }
2934 
2935 // Decode a shifted immediate operand.  These basically consist
2936 // of an 8-bit value, and a 4-bit directive that specifies either
2937 // a splat operation or a rotation.
2938 static DecodeStatus DecodeT2SOImm(llvm::MCInst &Inst, unsigned Val,
2939                           uint64_t Address, const void *Decoder) {
2940   unsigned ctrl = fieldFromInstruction32(Val, 10, 2);
2941   if (ctrl == 0) {
2942     unsigned byte = fieldFromInstruction32(Val, 8, 2);
2943     unsigned imm = fieldFromInstruction32(Val, 0, 8);
2944     switch (byte) {
2945       case 0:
2946         Inst.addOperand(MCOperand::CreateImm(imm));
2947         break;
2948       case 1:
2949         Inst.addOperand(MCOperand::CreateImm((imm << 16) | imm));
2950         break;
2951       case 2:
2952         Inst.addOperand(MCOperand::CreateImm((imm << 24) | (imm << 8)));
2953         break;
2954       case 3:
2955         Inst.addOperand(MCOperand::CreateImm((imm << 24) | (imm << 16) |
2956                                              (imm << 8)  |  imm));
2957         break;
2958     }
2959   } else {
2960     unsigned unrot = fieldFromInstruction32(Val, 0, 7) | 0x80;
2961     unsigned rot = fieldFromInstruction32(Val, 7, 5);
2962     unsigned imm = (unrot >> rot) | (unrot << ((32-rot)&31));
2963     Inst.addOperand(MCOperand::CreateImm(imm));
2964   }
2965 
2966   return MCDisassembler::Success;
2967 }
2968 
2969 static DecodeStatus
2970 DecodeThumbBCCTargetOperand(llvm::MCInst &Inst, unsigned Val,
2971                             uint64_t Address, const void *Decoder){
2972   Inst.addOperand(MCOperand::CreateImm(Val << 1));
2973   return MCDisassembler::Success;
2974 }
2975 
2976 static DecodeStatus DecodeThumbBLTargetOperand(llvm::MCInst &Inst, unsigned Val,
2977                                        uint64_t Address, const void *Decoder){
2978   Inst.addOperand(MCOperand::CreateImm(SignExtend32<22>(Val << 1)));
2979   return MCDisassembler::Success;
2980 }
2981 
2982 static DecodeStatus DecodeMemBarrierOption(llvm::MCInst &Inst, unsigned Val,
2983                                    uint64_t Address, const void *Decoder) {
2984   switch (Val) {
2985   default:
2986     return MCDisassembler::Fail;
2987   case 0xF: // SY
2988   case 0xE: // ST
2989   case 0xB: // ISH
2990   case 0xA: // ISHST
2991   case 0x7: // NSH
2992   case 0x6: // NSHST
2993   case 0x3: // OSH
2994   case 0x2: // OSHST
2995     break;
2996   }
2997 
2998   Inst.addOperand(MCOperand::CreateImm(Val));
2999   return MCDisassembler::Success;
3000 }
3001 
3002 static DecodeStatus DecodeMSRMask(llvm::MCInst &Inst, unsigned Val,
3003                           uint64_t Address, const void *Decoder) {
3004   if (!Val) return MCDisassembler::Fail;
3005   Inst.addOperand(MCOperand::CreateImm(Val));
3006   return MCDisassembler::Success;
3007 }
3008 
3009 static DecodeStatus DecodeDoubleRegLoad(llvm::MCInst &Inst, unsigned Insn,
3010                                         uint64_t Address, const void *Decoder) {
3011   DecodeStatus S = MCDisassembler::Success;
3012 
3013   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3014   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3015   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3016 
3017   if ((Rt & 1) || Rt == 0xE || Rn == 0xF) return MCDisassembler::Fail;
3018 
3019   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3020     return MCDisassembler::Fail;
3021   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
3022     return MCDisassembler::Fail;
3023   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3024     return MCDisassembler::Fail;
3025   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3026     return MCDisassembler::Fail;
3027 
3028   return S;
3029 }
3030 
3031 
3032 static DecodeStatus DecodeDoubleRegStore(llvm::MCInst &Inst, unsigned Insn,
3033                                          uint64_t Address, const void *Decoder){
3034   DecodeStatus S = MCDisassembler::Success;
3035 
3036   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3037   unsigned Rt = fieldFromInstruction32(Insn, 0, 4);
3038   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3039   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3040 
3041   if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
3042     return MCDisassembler::Fail;
3043 
3044   if ((Rt & 1) || Rt == 0xE || Rn == 0xF) return MCDisassembler::Fail;
3045   if (Rd == Rn || Rd == Rt || Rd == Rt+1) return MCDisassembler::Fail;
3046 
3047   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3048     return MCDisassembler::Fail;
3049   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
3050     return MCDisassembler::Fail;
3051   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3052     return MCDisassembler::Fail;
3053   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3054     return MCDisassembler::Fail;
3055 
3056   return S;
3057 }
3058 
3059 static DecodeStatus DecodeLDRPreImm(llvm::MCInst &Inst, unsigned Insn,
3060                             uint64_t Address, const void *Decoder) {
3061   DecodeStatus S = MCDisassembler::Success;
3062 
3063   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3064   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3065   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3066   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3067   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3068   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3069 
3070   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3071 
3072   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3073     return MCDisassembler::Fail;
3074   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3075     return MCDisassembler::Fail;
3076   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
3077     return MCDisassembler::Fail;
3078   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3079     return MCDisassembler::Fail;
3080 
3081   return S;
3082 }
3083 
3084 static DecodeStatus DecodeLDRPreReg(llvm::MCInst &Inst, unsigned Insn,
3085                             uint64_t Address, const void *Decoder) {
3086   DecodeStatus S = MCDisassembler::Success;
3087 
3088   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3089   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3090   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3091   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3092   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3093   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3094   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3095 
3096   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3097   if (Rm == 0xF) S = MCDisassembler::SoftFail;
3098 
3099   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3100     return MCDisassembler::Fail;
3101   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3102     return MCDisassembler::Fail;
3103   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
3104     return MCDisassembler::Fail;
3105   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3106     return MCDisassembler::Fail;
3107 
3108   return S;
3109 }
3110 
3111 
3112 static DecodeStatus DecodeSTRPreImm(llvm::MCInst &Inst, unsigned Insn,
3113                             uint64_t Address, const void *Decoder) {
3114   DecodeStatus S = MCDisassembler::Success;
3115 
3116   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3117   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3118   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3119   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3120   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3121   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3122 
3123   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3124 
3125   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3126     return MCDisassembler::Fail;
3127   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3128     return MCDisassembler::Fail;
3129   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
3130     return MCDisassembler::Fail;
3131   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3132     return MCDisassembler::Fail;
3133 
3134   return S;
3135 }
3136 
3137 static DecodeStatus DecodeSTRPreReg(llvm::MCInst &Inst, unsigned Insn,
3138                             uint64_t Address, const void *Decoder) {
3139   DecodeStatus S = MCDisassembler::Success;
3140 
3141   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3142   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3143   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3144   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3145   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3146   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3147 
3148   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3149 
3150   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3151     return MCDisassembler::Fail;
3152   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3153     return MCDisassembler::Fail;
3154   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
3155     return MCDisassembler::Fail;
3156   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3157     return MCDisassembler::Fail;
3158 
3159   return S;
3160 }
3161 
3162 static DecodeStatus DecodeVLD1LN(llvm::MCInst &Inst, unsigned Insn,
3163                          uint64_t Address, const void *Decoder) {
3164   DecodeStatus S = MCDisassembler::Success;
3165 
3166   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3167   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3168   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3169   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3170   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3171 
3172   unsigned align = 0;
3173   unsigned index = 0;
3174   switch (size) {
3175     default:
3176       return MCDisassembler::Fail;
3177     case 0:
3178       if (fieldFromInstruction32(Insn, 4, 1))
3179         return MCDisassembler::Fail; // UNDEFINED
3180       index = fieldFromInstruction32(Insn, 5, 3);
3181       break;
3182     case 1:
3183       if (fieldFromInstruction32(Insn, 5, 1))
3184         return MCDisassembler::Fail; // UNDEFINED
3185       index = fieldFromInstruction32(Insn, 6, 2);
3186       if (fieldFromInstruction32(Insn, 4, 1))
3187         align = 2;
3188       break;
3189     case 2:
3190       if (fieldFromInstruction32(Insn, 6, 1))
3191         return MCDisassembler::Fail; // UNDEFINED
3192       index = fieldFromInstruction32(Insn, 7, 1);
3193       if (fieldFromInstruction32(Insn, 4, 2) != 0)
3194         align = 4;
3195   }
3196 
3197   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3198     return MCDisassembler::Fail;
3199   if (Rm != 0xF) { // Writeback
3200     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3201       return MCDisassembler::Fail;
3202   }
3203   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3204     return MCDisassembler::Fail;
3205   Inst.addOperand(MCOperand::CreateImm(align));
3206   if (Rm != 0xF) {
3207     if (Rm != 0xD) {
3208       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3209         return MCDisassembler::Fail;
3210     } else
3211       Inst.addOperand(MCOperand::CreateReg(0));
3212   }
3213 
3214   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3215     return MCDisassembler::Fail;
3216   Inst.addOperand(MCOperand::CreateImm(index));
3217 
3218   return S;
3219 }
3220 
3221 static DecodeStatus DecodeVST1LN(llvm::MCInst &Inst, unsigned Insn,
3222                          uint64_t Address, const void *Decoder) {
3223   DecodeStatus S = MCDisassembler::Success;
3224 
3225   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3226   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3227   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3228   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3229   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3230 
3231   unsigned align = 0;
3232   unsigned index = 0;
3233   switch (size) {
3234     default:
3235       return MCDisassembler::Fail;
3236     case 0:
3237       if (fieldFromInstruction32(Insn, 4, 1))
3238         return MCDisassembler::Fail; // UNDEFINED
3239       index = fieldFromInstruction32(Insn, 5, 3);
3240       break;
3241     case 1:
3242       if (fieldFromInstruction32(Insn, 5, 1))
3243         return MCDisassembler::Fail; // UNDEFINED
3244       index = fieldFromInstruction32(Insn, 6, 2);
3245       if (fieldFromInstruction32(Insn, 4, 1))
3246         align = 2;
3247       break;
3248     case 2:
3249       if (fieldFromInstruction32(Insn, 6, 1))
3250         return MCDisassembler::Fail; // UNDEFINED
3251       index = fieldFromInstruction32(Insn, 7, 1);
3252       if (fieldFromInstruction32(Insn, 4, 2) != 0)
3253         align = 4;
3254   }
3255 
3256   if (Rm != 0xF) { // Writeback
3257     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3258     return MCDisassembler::Fail;
3259   }
3260   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3261     return MCDisassembler::Fail;
3262   Inst.addOperand(MCOperand::CreateImm(align));
3263   if (Rm != 0xF) {
3264     if (Rm != 0xD) {
3265       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3266     return MCDisassembler::Fail;
3267     } else
3268       Inst.addOperand(MCOperand::CreateReg(0));
3269   }
3270 
3271   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3272     return MCDisassembler::Fail;
3273   Inst.addOperand(MCOperand::CreateImm(index));
3274 
3275   return S;
3276 }
3277 
3278 
3279 static DecodeStatus DecodeVLD2LN(llvm::MCInst &Inst, unsigned Insn,
3280                          uint64_t Address, const void *Decoder) {
3281   DecodeStatus S = MCDisassembler::Success;
3282 
3283   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3284   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3285   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3286   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3287   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3288 
3289   unsigned align = 0;
3290   unsigned index = 0;
3291   unsigned inc = 1;
3292   switch (size) {
3293     default:
3294       return MCDisassembler::Fail;
3295     case 0:
3296       index = fieldFromInstruction32(Insn, 5, 3);
3297       if (fieldFromInstruction32(Insn, 4, 1))
3298         align = 2;
3299       break;
3300     case 1:
3301       index = fieldFromInstruction32(Insn, 6, 2);
3302       if (fieldFromInstruction32(Insn, 4, 1))
3303         align = 4;
3304       if (fieldFromInstruction32(Insn, 5, 1))
3305         inc = 2;
3306       break;
3307     case 2:
3308       if (fieldFromInstruction32(Insn, 5, 1))
3309         return MCDisassembler::Fail; // UNDEFINED
3310       index = fieldFromInstruction32(Insn, 7, 1);
3311       if (fieldFromInstruction32(Insn, 4, 1) != 0)
3312         align = 8;
3313       if (fieldFromInstruction32(Insn, 6, 1))
3314         inc = 2;
3315       break;
3316   }
3317 
3318   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3319     return MCDisassembler::Fail;
3320   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3321     return MCDisassembler::Fail;
3322   if (Rm != 0xF) { // Writeback
3323     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3324       return MCDisassembler::Fail;
3325   }
3326   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3327     return MCDisassembler::Fail;
3328   Inst.addOperand(MCOperand::CreateImm(align));
3329   if (Rm != 0xF) {
3330     if (Rm != 0xD) {
3331       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3332         return MCDisassembler::Fail;
3333     } else
3334       Inst.addOperand(MCOperand::CreateReg(0));
3335   }
3336 
3337   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3338     return MCDisassembler::Fail;
3339   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3340     return MCDisassembler::Fail;
3341   Inst.addOperand(MCOperand::CreateImm(index));
3342 
3343   return S;
3344 }
3345 
3346 static DecodeStatus DecodeVST2LN(llvm::MCInst &Inst, unsigned Insn,
3347                          uint64_t Address, const void *Decoder) {
3348   DecodeStatus S = MCDisassembler::Success;
3349 
3350   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3351   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3352   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3353   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3354   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3355 
3356   unsigned align = 0;
3357   unsigned index = 0;
3358   unsigned inc = 1;
3359   switch (size) {
3360     default:
3361       return MCDisassembler::Fail;
3362     case 0:
3363       index = fieldFromInstruction32(Insn, 5, 3);
3364       if (fieldFromInstruction32(Insn, 4, 1))
3365         align = 2;
3366       break;
3367     case 1:
3368       index = fieldFromInstruction32(Insn, 6, 2);
3369       if (fieldFromInstruction32(Insn, 4, 1))
3370         align = 4;
3371       if (fieldFromInstruction32(Insn, 5, 1))
3372         inc = 2;
3373       break;
3374     case 2:
3375       if (fieldFromInstruction32(Insn, 5, 1))
3376         return MCDisassembler::Fail; // UNDEFINED
3377       index = fieldFromInstruction32(Insn, 7, 1);
3378       if (fieldFromInstruction32(Insn, 4, 1) != 0)
3379         align = 8;
3380       if (fieldFromInstruction32(Insn, 6, 1))
3381         inc = 2;
3382       break;
3383   }
3384 
3385   if (Rm != 0xF) { // Writeback
3386     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3387       return MCDisassembler::Fail;
3388   }
3389   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3390     return MCDisassembler::Fail;
3391   Inst.addOperand(MCOperand::CreateImm(align));
3392   if (Rm != 0xF) {
3393     if (Rm != 0xD) {
3394       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3395         return MCDisassembler::Fail;
3396     } else
3397       Inst.addOperand(MCOperand::CreateReg(0));
3398   }
3399 
3400   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3401     return MCDisassembler::Fail;
3402   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3403     return MCDisassembler::Fail;
3404   Inst.addOperand(MCOperand::CreateImm(index));
3405 
3406   return S;
3407 }
3408 
3409 
3410 static DecodeStatus DecodeVLD3LN(llvm::MCInst &Inst, unsigned Insn,
3411                          uint64_t Address, const void *Decoder) {
3412   DecodeStatus S = MCDisassembler::Success;
3413 
3414   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3415   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3416   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3417   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3418   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3419 
3420   unsigned align = 0;
3421   unsigned index = 0;
3422   unsigned inc = 1;
3423   switch (size) {
3424     default:
3425       return MCDisassembler::Fail;
3426     case 0:
3427       if (fieldFromInstruction32(Insn, 4, 1))
3428         return MCDisassembler::Fail; // UNDEFINED
3429       index = fieldFromInstruction32(Insn, 5, 3);
3430       break;
3431     case 1:
3432       if (fieldFromInstruction32(Insn, 4, 1))
3433         return MCDisassembler::Fail; // UNDEFINED
3434       index = fieldFromInstruction32(Insn, 6, 2);
3435       if (fieldFromInstruction32(Insn, 5, 1))
3436         inc = 2;
3437       break;
3438     case 2:
3439       if (fieldFromInstruction32(Insn, 4, 2))
3440         return MCDisassembler::Fail; // UNDEFINED
3441       index = fieldFromInstruction32(Insn, 7, 1);
3442       if (fieldFromInstruction32(Insn, 6, 1))
3443         inc = 2;
3444       break;
3445   }
3446 
3447   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3448     return MCDisassembler::Fail;
3449   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3450     return MCDisassembler::Fail;
3451   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3452     return MCDisassembler::Fail;
3453 
3454   if (Rm != 0xF) { // Writeback
3455     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3456     return MCDisassembler::Fail;
3457   }
3458   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3459     return MCDisassembler::Fail;
3460   Inst.addOperand(MCOperand::CreateImm(align));
3461   if (Rm != 0xF) {
3462     if (Rm != 0xD) {
3463       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3464     return MCDisassembler::Fail;
3465     } else
3466       Inst.addOperand(MCOperand::CreateReg(0));
3467   }
3468 
3469   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3470     return MCDisassembler::Fail;
3471   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3472     return MCDisassembler::Fail;
3473   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3474     return MCDisassembler::Fail;
3475   Inst.addOperand(MCOperand::CreateImm(index));
3476 
3477   return S;
3478 }
3479 
3480 static DecodeStatus DecodeVST3LN(llvm::MCInst &Inst, unsigned Insn,
3481                          uint64_t Address, const void *Decoder) {
3482   DecodeStatus S = MCDisassembler::Success;
3483 
3484   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3485   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3486   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3487   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3488   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3489 
3490   unsigned align = 0;
3491   unsigned index = 0;
3492   unsigned inc = 1;
3493   switch (size) {
3494     default:
3495       return MCDisassembler::Fail;
3496     case 0:
3497       if (fieldFromInstruction32(Insn, 4, 1))
3498         return MCDisassembler::Fail; // UNDEFINED
3499       index = fieldFromInstruction32(Insn, 5, 3);
3500       break;
3501     case 1:
3502       if (fieldFromInstruction32(Insn, 4, 1))
3503         return MCDisassembler::Fail; // UNDEFINED
3504       index = fieldFromInstruction32(Insn, 6, 2);
3505       if (fieldFromInstruction32(Insn, 5, 1))
3506         inc = 2;
3507       break;
3508     case 2:
3509       if (fieldFromInstruction32(Insn, 4, 2))
3510         return MCDisassembler::Fail; // UNDEFINED
3511       index = fieldFromInstruction32(Insn, 7, 1);
3512       if (fieldFromInstruction32(Insn, 6, 1))
3513         inc = 2;
3514       break;
3515   }
3516 
3517   if (Rm != 0xF) { // Writeback
3518     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3519     return MCDisassembler::Fail;
3520   }
3521   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3522     return MCDisassembler::Fail;
3523   Inst.addOperand(MCOperand::CreateImm(align));
3524   if (Rm != 0xF) {
3525     if (Rm != 0xD) {
3526       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3527     return MCDisassembler::Fail;
3528     } else
3529       Inst.addOperand(MCOperand::CreateReg(0));
3530   }
3531 
3532   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3533     return MCDisassembler::Fail;
3534   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3535     return MCDisassembler::Fail;
3536   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3537     return MCDisassembler::Fail;
3538   Inst.addOperand(MCOperand::CreateImm(index));
3539 
3540   return S;
3541 }
3542 
3543 
3544 static DecodeStatus DecodeVLD4LN(llvm::MCInst &Inst, unsigned Insn,
3545                          uint64_t Address, const void *Decoder) {
3546   DecodeStatus S = MCDisassembler::Success;
3547 
3548   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3549   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3550   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3551   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3552   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3553 
3554   unsigned align = 0;
3555   unsigned index = 0;
3556   unsigned inc = 1;
3557   switch (size) {
3558     default:
3559       return MCDisassembler::Fail;
3560     case 0:
3561       if (fieldFromInstruction32(Insn, 4, 1))
3562         align = 4;
3563       index = fieldFromInstruction32(Insn, 5, 3);
3564       break;
3565     case 1:
3566       if (fieldFromInstruction32(Insn, 4, 1))
3567         align = 8;
3568       index = fieldFromInstruction32(Insn, 6, 2);
3569       if (fieldFromInstruction32(Insn, 5, 1))
3570         inc = 2;
3571       break;
3572     case 2:
3573       if (fieldFromInstruction32(Insn, 4, 2))
3574         align = 4 << fieldFromInstruction32(Insn, 4, 2);
3575       index = fieldFromInstruction32(Insn, 7, 1);
3576       if (fieldFromInstruction32(Insn, 6, 1))
3577         inc = 2;
3578       break;
3579   }
3580 
3581   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3582     return MCDisassembler::Fail;
3583   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3584     return MCDisassembler::Fail;
3585   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3586     return MCDisassembler::Fail;
3587   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
3588     return MCDisassembler::Fail;
3589 
3590   if (Rm != 0xF) { // Writeback
3591     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3592       return MCDisassembler::Fail;
3593   }
3594   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3595     return MCDisassembler::Fail;
3596   Inst.addOperand(MCOperand::CreateImm(align));
3597   if (Rm != 0xF) {
3598     if (Rm != 0xD) {
3599       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3600         return MCDisassembler::Fail;
3601     } else
3602       Inst.addOperand(MCOperand::CreateReg(0));
3603   }
3604 
3605   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3606     return MCDisassembler::Fail;
3607   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3608     return MCDisassembler::Fail;
3609   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3610     return MCDisassembler::Fail;
3611   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
3612     return MCDisassembler::Fail;
3613   Inst.addOperand(MCOperand::CreateImm(index));
3614 
3615   return S;
3616 }
3617 
3618 static DecodeStatus DecodeVST4LN(llvm::MCInst &Inst, unsigned Insn,
3619                          uint64_t Address, const void *Decoder) {
3620   DecodeStatus S = MCDisassembler::Success;
3621 
3622   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3623   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3624   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3625   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3626   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3627 
3628   unsigned align = 0;
3629   unsigned index = 0;
3630   unsigned inc = 1;
3631   switch (size) {
3632     default:
3633       return MCDisassembler::Fail;
3634     case 0:
3635       if (fieldFromInstruction32(Insn, 4, 1))
3636         align = 4;
3637       index = fieldFromInstruction32(Insn, 5, 3);
3638       break;
3639     case 1:
3640       if (fieldFromInstruction32(Insn, 4, 1))
3641         align = 8;
3642       index = fieldFromInstruction32(Insn, 6, 2);
3643       if (fieldFromInstruction32(Insn, 5, 1))
3644         inc = 2;
3645       break;
3646     case 2:
3647       if (fieldFromInstruction32(Insn, 4, 2))
3648         align = 4 << fieldFromInstruction32(Insn, 4, 2);
3649       index = fieldFromInstruction32(Insn, 7, 1);
3650       if (fieldFromInstruction32(Insn, 6, 1))
3651         inc = 2;
3652       break;
3653   }
3654 
3655   if (Rm != 0xF) { // Writeback
3656     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3657     return MCDisassembler::Fail;
3658   }
3659   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3660     return MCDisassembler::Fail;
3661   Inst.addOperand(MCOperand::CreateImm(align));
3662   if (Rm != 0xF) {
3663     if (Rm != 0xD) {
3664       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3665     return MCDisassembler::Fail;
3666     } else
3667       Inst.addOperand(MCOperand::CreateReg(0));
3668   }
3669 
3670   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3671     return MCDisassembler::Fail;
3672   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3673     return MCDisassembler::Fail;
3674   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3675     return MCDisassembler::Fail;
3676   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
3677     return MCDisassembler::Fail;
3678   Inst.addOperand(MCOperand::CreateImm(index));
3679 
3680   return S;
3681 }
3682 
3683 static DecodeStatus DecodeVMOVSRR(llvm::MCInst &Inst, unsigned Insn,
3684                                   uint64_t Address, const void *Decoder) {
3685   DecodeStatus S = MCDisassembler::Success;
3686   unsigned Rt  = fieldFromInstruction32(Insn, 12, 4);
3687   unsigned Rt2 = fieldFromInstruction32(Insn, 16, 4);
3688   unsigned Rm  = fieldFromInstruction32(Insn,  0, 4);
3689   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3690   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
3691 
3692   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
3693     S = MCDisassembler::SoftFail;
3694 
3695   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
3696     return MCDisassembler::Fail;
3697   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
3698     return MCDisassembler::Fail;
3699   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
3700     return MCDisassembler::Fail;
3701   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
3702     return MCDisassembler::Fail;
3703   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3704     return MCDisassembler::Fail;
3705 
3706   return S;
3707 }
3708 
3709 static DecodeStatus DecodeVMOVRRS(llvm::MCInst &Inst, unsigned Insn,
3710                                   uint64_t Address, const void *Decoder) {
3711   DecodeStatus S = MCDisassembler::Success;
3712   unsigned Rt  = fieldFromInstruction32(Insn, 12, 4);
3713   unsigned Rt2 = fieldFromInstruction32(Insn, 16, 4);
3714   unsigned Rm  = fieldFromInstruction32(Insn,  0, 4);
3715   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3716   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
3717 
3718   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
3719     S = MCDisassembler::SoftFail;
3720 
3721   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
3722     return MCDisassembler::Fail;
3723   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
3724     return MCDisassembler::Fail;
3725   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
3726     return MCDisassembler::Fail;
3727   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
3728     return MCDisassembler::Fail;
3729   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3730     return MCDisassembler::Fail;
3731 
3732   return S;
3733 }
3734 
3735 static DecodeStatus DecodeIT(llvm::MCInst &Inst, unsigned Insn,
3736                              uint64_t Address, const void *Decoder) {
3737   DecodeStatus S = MCDisassembler::Success;
3738   unsigned pred = fieldFromInstruction16(Insn, 4, 4);
3739   // The InstPrinter needs to have the low bit of the predicate in
3740   // the mask operand to be able to print it properly.
3741   unsigned mask = fieldFromInstruction16(Insn, 0, 5);
3742 
3743   if (pred == 0xF) {
3744     pred = 0xE;
3745     S = MCDisassembler::SoftFail;
3746   }
3747 
3748   if ((mask & 0xF) == 0) {
3749     // Preserve the high bit of the mask, which is the low bit of
3750     // the predicate.
3751     mask &= 0x10;
3752     mask |= 0x8;
3753     S = MCDisassembler::SoftFail;
3754   }
3755 
3756   Inst.addOperand(MCOperand::CreateImm(pred));
3757   Inst.addOperand(MCOperand::CreateImm(mask));
3758   return S;
3759 }
3760 
3761 static DecodeStatus
3762 DecodeT2LDRDPreInstruction(llvm::MCInst &Inst, unsigned Insn,
3763                            uint64_t Address, const void *Decoder) {
3764   DecodeStatus S = MCDisassembler::Success;
3765 
3766   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3767   unsigned Rt2 = fieldFromInstruction32(Insn, 8, 4);
3768   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3769   unsigned addr = fieldFromInstruction32(Insn, 0, 8);
3770   unsigned W = fieldFromInstruction32(Insn, 21, 1);
3771   unsigned U = fieldFromInstruction32(Insn, 23, 1);
3772   unsigned P = fieldFromInstruction32(Insn, 24, 1);
3773   bool writeback = (W == 1) | (P == 0);
3774 
3775   addr |= (U << 8) | (Rn << 9);
3776 
3777   if (writeback && (Rn == Rt || Rn == Rt2))
3778     Check(S, MCDisassembler::SoftFail);
3779   if (Rt == Rt2)
3780     Check(S, MCDisassembler::SoftFail);
3781 
3782   // Rt
3783   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
3784     return MCDisassembler::Fail;
3785   // Rt2
3786   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
3787     return MCDisassembler::Fail;
3788   // Writeback operand
3789   if (!Check(S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
3790     return MCDisassembler::Fail;
3791   // addr
3792   if (!Check(S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
3793     return MCDisassembler::Fail;
3794 
3795   return S;
3796 }
3797 
3798 static DecodeStatus
3799 DecodeT2STRDPreInstruction(llvm::MCInst &Inst, unsigned Insn,
3800                            uint64_t Address, const void *Decoder) {
3801   DecodeStatus S = MCDisassembler::Success;
3802 
3803   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3804   unsigned Rt2 = fieldFromInstruction32(Insn, 8, 4);
3805   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3806   unsigned addr = fieldFromInstruction32(Insn, 0, 8);
3807   unsigned W = fieldFromInstruction32(Insn, 21, 1);
3808   unsigned U = fieldFromInstruction32(Insn, 23, 1);
3809   unsigned P = fieldFromInstruction32(Insn, 24, 1);
3810   bool writeback = (W == 1) | (P == 0);
3811 
3812   addr |= (U << 8) | (Rn << 9);
3813 
3814   if (writeback && (Rn == Rt || Rn == Rt2))
3815     Check(S, MCDisassembler::SoftFail);
3816 
3817   // Writeback operand
3818   if (!Check(S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
3819     return MCDisassembler::Fail;
3820   // Rt
3821   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
3822     return MCDisassembler::Fail;
3823   // Rt2
3824   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
3825     return MCDisassembler::Fail;
3826   // addr
3827   if (!Check(S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
3828     return MCDisassembler::Fail;
3829 
3830   return S;
3831 }
3832 
3833 static DecodeStatus DecodeT2Adr(llvm::MCInst &Inst, uint32_t Insn,
3834                                 uint64_t Address, const void *Decoder) {
3835   unsigned sign1 = fieldFromInstruction32(Insn, 21, 1);
3836   unsigned sign2 = fieldFromInstruction32(Insn, 23, 1);
3837   if (sign1 != sign2) return MCDisassembler::Fail;
3838 
3839   unsigned Val = fieldFromInstruction32(Insn, 0, 8);
3840   Val |= fieldFromInstruction32(Insn, 12, 3) << 8;
3841   Val |= fieldFromInstruction32(Insn, 26, 1) << 11;
3842   Val |= sign1 << 12;
3843   Inst.addOperand(MCOperand::CreateImm(SignExtend32<13>(Val)));
3844 
3845   return MCDisassembler::Success;
3846 }
3847 
3848