xref: /llvm-project/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp (revision 4c493e8050c31de9fbfb9899ed59023336168347)
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) const;
51 
52   /// getEDInfo - See MCDisassembler.
53   EDInstInfo *getEDInfo() const;
54 private:
55 };
56 
57 /// ThumbDisassembler - Thumb disassembler for all Thumb platforms.
58 class ThumbDisassembler : public MCDisassembler {
59 public:
60   /// Constructor     - Initializes the disassembler.
61   ///
62   ThumbDisassembler(const MCSubtargetInfo &STI) :
63     MCDisassembler(STI) {
64   }
65 
66   ~ThumbDisassembler() {
67   }
68 
69   /// getInstruction - See MCDisassembler.
70   DecodeStatus getInstruction(MCInst &instr,
71                               uint64_t &size,
72                               const MemoryObject &region,
73                               uint64_t address,
74                               raw_ostream &vStream) const;
75 
76   /// getEDInfo - See MCDisassembler.
77   EDInstInfo *getEDInfo() const;
78 private:
79   mutable std::vector<unsigned> ITBlock;
80   void AddThumbPredicate(MCInst&) const;
81   void UpdateThumbVFPPredicate(MCInst&) const;
82 };
83 }
84 
85 static bool Check(DecodeStatus &Out, DecodeStatus In) {
86   switch (In) {
87     case MCDisassembler::Success:
88       // Out stays the same.
89       return true;
90     case MCDisassembler::SoftFail:
91       Out = In;
92       return true;
93     case MCDisassembler::Fail:
94       Out = In;
95       return false;
96   }
97   return false;
98 }
99 
100 // Forward declare these because the autogenerated code will reference them.
101 // Definitions are further down.
102 static DecodeStatus DecodeGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
103                                    uint64_t Address, const void *Decoder);
104 static DecodeStatus DecodeGPRnopcRegisterClass(llvm::MCInst &Inst,
105                                                unsigned RegNo, uint64_t Address,
106                                                const void *Decoder);
107 static DecodeStatus DecodetGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
108                                    uint64_t Address, const void *Decoder);
109 static DecodeStatus DecodetcGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
110                                    uint64_t Address, const void *Decoder);
111 static DecodeStatus DecoderGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
112                                    uint64_t Address, const void *Decoder);
113 static DecodeStatus DecodeSPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
114                                    uint64_t Address, const void *Decoder);
115 static DecodeStatus DecodeDPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
116                                    uint64_t Address, const void *Decoder);
117 static DecodeStatus DecodeDPR_8RegisterClass(llvm::MCInst &Inst, unsigned RegNo,
118                                    uint64_t Address, const void *Decoder);
119 static DecodeStatus DecodeDPR_VFP2RegisterClass(llvm::MCInst &Inst,
120                                                 unsigned RegNo,
121                                                 uint64_t Address,
122                                                 const void *Decoder);
123 static DecodeStatus DecodeQPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
124                                    uint64_t Address, const void *Decoder);
125 
126 static DecodeStatus DecodePredicateOperand(llvm::MCInst &Inst, unsigned Val,
127                                uint64_t Address, const void *Decoder);
128 static DecodeStatus DecodeCCOutOperand(llvm::MCInst &Inst, unsigned Val,
129                                uint64_t Address, const void *Decoder);
130 static DecodeStatus DecodeSOImmOperand(llvm::MCInst &Inst, unsigned Val,
131                                uint64_t Address, const void *Decoder);
132 static DecodeStatus DecodeRegListOperand(llvm::MCInst &Inst, unsigned Val,
133                                uint64_t Address, const void *Decoder);
134 static DecodeStatus DecodeSPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
135                                uint64_t Address, const void *Decoder);
136 static DecodeStatus DecodeDPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
137                                uint64_t Address, const void *Decoder);
138 
139 static DecodeStatus DecodeBitfieldMaskOperand(llvm::MCInst &Inst, unsigned Insn,
140                                uint64_t Address, const void *Decoder);
141 static DecodeStatus DecodeCopMemInstruction(llvm::MCInst &Inst, unsigned Insn,
142                                uint64_t Address, const void *Decoder);
143 static DecodeStatus DecodeAddrMode2IdxInstruction(llvm::MCInst &Inst,
144                                                   unsigned Insn,
145                                                   uint64_t Address,
146                                                   const void *Decoder);
147 static DecodeStatus DecodeSORegMemOperand(llvm::MCInst &Inst, unsigned Insn,
148                                uint64_t Address, const void *Decoder);
149 static DecodeStatus DecodeAddrMode3Instruction(llvm::MCInst &Inst,unsigned Insn,
150                                uint64_t Address, const void *Decoder);
151 static DecodeStatus DecodeSORegImmOperand(llvm::MCInst &Inst, unsigned Insn,
152                                uint64_t Address, const void *Decoder);
153 static DecodeStatus DecodeSORegRegOperand(llvm::MCInst &Inst, unsigned Insn,
154                                uint64_t Address, const void *Decoder);
155 
156 static DecodeStatus DecodeMemMultipleWritebackInstruction(llvm::MCInst & Inst,
157                                                   unsigned Insn,
158                                                   uint64_t Adddress,
159                                                   const void *Decoder);
160 static DecodeStatus DecodeSMLAInstruction(llvm::MCInst &Inst, unsigned Insn,
161                                uint64_t Address, const void *Decoder);
162 static DecodeStatus DecodeCPSInstruction(llvm::MCInst &Inst, unsigned Insn,
163                                uint64_t Address, const void *Decoder);
164 static DecodeStatus DecodeT2CPSInstruction(llvm::MCInst &Inst, unsigned Insn,
165                                uint64_t Address, const void *Decoder);
166 static DecodeStatus DecodeAddrModeImm12Operand(llvm::MCInst &Inst, unsigned Val,
167                                uint64_t Address, const void *Decoder);
168 static DecodeStatus DecodeAddrMode5Operand(llvm::MCInst &Inst, unsigned Val,
169                                uint64_t Address, const void *Decoder);
170 static DecodeStatus DecodeAddrMode7Operand(llvm::MCInst &Inst, unsigned Val,
171                                uint64_t Address, const void *Decoder);
172 static DecodeStatus DecodeBranchImmInstruction(llvm::MCInst &Inst,unsigned Insn,
173                                uint64_t Address, const void *Decoder);
174 static DecodeStatus DecodeVCVTImmOperand(llvm::MCInst &Inst, unsigned Val,
175                                uint64_t Address, const void *Decoder);
176 static DecodeStatus DecodeAddrMode6Operand(llvm::MCInst &Inst, unsigned Val,
177                                uint64_t Address, const void *Decoder);
178 static DecodeStatus DecodeVLDInstruction(llvm::MCInst &Inst, unsigned Val,
179                                uint64_t Address, const void *Decoder);
180 static DecodeStatus DecodeVSTInstruction(llvm::MCInst &Inst, unsigned Val,
181                                uint64_t Address, const void *Decoder);
182 static DecodeStatus DecodeVLD1DupInstruction(llvm::MCInst &Inst, unsigned Val,
183                                uint64_t Address, const void *Decoder);
184 static DecodeStatus DecodeVLD2DupInstruction(llvm::MCInst &Inst, unsigned Val,
185                                uint64_t Address, const void *Decoder);
186 static DecodeStatus DecodeVLD3DupInstruction(llvm::MCInst &Inst, unsigned Val,
187                                uint64_t Address, const void *Decoder);
188 static DecodeStatus DecodeVLD4DupInstruction(llvm::MCInst &Inst, unsigned Val,
189                                uint64_t Address, const void *Decoder);
190 static DecodeStatus DecodeNEONModImmInstruction(llvm::MCInst &Inst,unsigned Val,
191                                uint64_t Address, const void *Decoder);
192 static DecodeStatus DecodeVSHLMaxInstruction(llvm::MCInst &Inst, unsigned Val,
193                                uint64_t Address, const void *Decoder);
194 static DecodeStatus DecodeShiftRight8Imm(llvm::MCInst &Inst, unsigned Val,
195                                uint64_t Address, const void *Decoder);
196 static DecodeStatus DecodeShiftRight16Imm(llvm::MCInst &Inst, unsigned Val,
197                                uint64_t Address, const void *Decoder);
198 static DecodeStatus DecodeShiftRight32Imm(llvm::MCInst &Inst, unsigned Val,
199                                uint64_t Address, const void *Decoder);
200 static DecodeStatus DecodeShiftRight64Imm(llvm::MCInst &Inst, unsigned Val,
201                                uint64_t Address, const void *Decoder);
202 static DecodeStatus DecodeTBLInstruction(llvm::MCInst &Inst, unsigned Insn,
203                                uint64_t Address, const void *Decoder);
204 static DecodeStatus DecodeVFPfpImm(llvm::MCInst &Inst, unsigned Val,
205                                uint64_t Address, const void *Decoder);
206 static DecodeStatus DecodePostIdxReg(llvm::MCInst &Inst, unsigned Insn,
207                                uint64_t Address, const void *Decoder);
208 static DecodeStatus DecodeCoprocessor(llvm::MCInst &Inst, unsigned Insn,
209                                uint64_t Address, const void *Decoder);
210 static DecodeStatus DecodeMemBarrierOption(llvm::MCInst &Inst, unsigned Insn,
211                                uint64_t Address, const void *Decoder);
212 static DecodeStatus DecodeMSRMask(llvm::MCInst &Inst, unsigned Insn,
213                                uint64_t Address, const void *Decoder);
214 static DecodeStatus DecodeDoubleRegLoad(llvm::MCInst &Inst, unsigned Insn,
215                                uint64_t Address, const void *Decoder);
216 static DecodeStatus DecodeDoubleRegStore(llvm::MCInst &Inst, unsigned Insn,
217                                uint64_t Address, const void *Decoder);
218 static DecodeStatus DecodeLDRPreImm(llvm::MCInst &Inst, unsigned Insn,
219                                uint64_t Address, const void *Decoder);
220 static DecodeStatus DecodeLDRPreReg(llvm::MCInst &Inst, unsigned Insn,
221                                uint64_t Address, const void *Decoder);
222 static DecodeStatus DecodeSTRPreImm(llvm::MCInst &Inst, unsigned Insn,
223                                uint64_t Address, const void *Decoder);
224 static DecodeStatus DecodeSTRPreReg(llvm::MCInst &Inst, unsigned Insn,
225                                uint64_t Address, const void *Decoder);
226 static DecodeStatus DecodeVLD1LN(llvm::MCInst &Inst, unsigned Insn,
227                                uint64_t Address, const void *Decoder);
228 static DecodeStatus DecodeVLD2LN(llvm::MCInst &Inst, unsigned Insn,
229                                uint64_t Address, const void *Decoder);
230 static DecodeStatus DecodeVLD3LN(llvm::MCInst &Inst, unsigned Insn,
231                                uint64_t Address, const void *Decoder);
232 static DecodeStatus DecodeVLD4LN(llvm::MCInst &Inst, unsigned Insn,
233                                uint64_t Address, const void *Decoder);
234 static DecodeStatus DecodeVST1LN(llvm::MCInst &Inst, unsigned Insn,
235                                uint64_t Address, const void *Decoder);
236 static DecodeStatus DecodeVST2LN(llvm::MCInst &Inst, unsigned Insn,
237                                uint64_t Address, const void *Decoder);
238 static DecodeStatus DecodeVST3LN(llvm::MCInst &Inst, unsigned Insn,
239                                uint64_t Address, const void *Decoder);
240 static DecodeStatus DecodeVST4LN(llvm::MCInst &Inst, unsigned Insn,
241                                uint64_t Address, const void *Decoder);
242 static DecodeStatus DecodeVMOVSRR(llvm::MCInst &Inst, unsigned Insn,
243                                uint64_t Address, const void *Decoder);
244 static DecodeStatus DecodeVMOVRRS(llvm::MCInst &Inst, unsigned Insn,
245                                uint64_t Address, const void *Decoder);
246 
247 static DecodeStatus DecodeThumbAddSpecialReg(llvm::MCInst &Inst, uint16_t Insn,
248                                uint64_t Address, const void *Decoder);
249 static DecodeStatus DecodeThumbBROperand(llvm::MCInst &Inst, unsigned Val,
250                                uint64_t Address, const void *Decoder);
251 static DecodeStatus DecodeT2BROperand(llvm::MCInst &Inst, unsigned Val,
252                                uint64_t Address, const void *Decoder);
253 static DecodeStatus DecodeThumbCmpBROperand(llvm::MCInst &Inst, unsigned Val,
254                                uint64_t Address, const void *Decoder);
255 static DecodeStatus DecodeThumbAddrModeRR(llvm::MCInst &Inst, unsigned Val,
256                                uint64_t Address, const void *Decoder);
257 static DecodeStatus DecodeThumbAddrModeIS(llvm::MCInst &Inst, unsigned Val,
258                                uint64_t Address, const void *Decoder);
259 static DecodeStatus DecodeThumbAddrModePC(llvm::MCInst &Inst, unsigned Val,
260                                uint64_t Address, const void *Decoder);
261 static DecodeStatus DecodeThumbAddrModeSP(llvm::MCInst &Inst, unsigned Val,
262                                uint64_t Address, const void *Decoder);
263 static DecodeStatus DecodeT2AddrModeSOReg(llvm::MCInst &Inst, unsigned Val,
264                                uint64_t Address, const void *Decoder);
265 static DecodeStatus DecodeT2LoadShift(llvm::MCInst &Inst, unsigned Val,
266                                uint64_t Address, const void *Decoder);
267 static DecodeStatus DecodeT2Imm8S4(llvm::MCInst &Inst, unsigned Val,
268                                uint64_t Address, const void *Decoder);
269 static DecodeStatus DecodeT2AddrModeImm8s4(llvm::MCInst &Inst, unsigned Val,
270                                uint64_t Address, const void *Decoder);
271 static DecodeStatus DecodeT2Imm8(llvm::MCInst &Inst, unsigned Val,
272                                uint64_t Address, const void *Decoder);
273 static DecodeStatus DecodeT2AddrModeImm8(llvm::MCInst &Inst, unsigned Val,
274                                uint64_t Address, const void *Decoder);
275 static DecodeStatus DecodeThumbAddSPImm(llvm::MCInst &Inst, uint16_t Val,
276                                uint64_t Address, const void *Decoder);
277 static DecodeStatus DecodeThumbAddSPReg(llvm::MCInst &Inst, uint16_t Insn,
278                                 uint64_t Address, const void *Decoder);
279 static DecodeStatus DecodeThumbCPS(llvm::MCInst &Inst, uint16_t Insn,
280                                 uint64_t Address, const void *Decoder);
281 static DecodeStatus DecodeThumbBLXOffset(llvm::MCInst &Inst, unsigned Insn,
282                                 uint64_t Address, const void *Decoder);
283 static DecodeStatus DecodeT2AddrModeImm12(llvm::MCInst &Inst, unsigned Val,
284                                 uint64_t Address, const void *Decoder);
285 static DecodeStatus DecodeThumb2BCCInstruction(llvm::MCInst &Inst, unsigned Val,
286                                 uint64_t Address, const void *Decoder);
287 static DecodeStatus DecodeT2SOImm(llvm::MCInst &Inst, unsigned Val,
288                                 uint64_t Address, const void *Decoder);
289 static DecodeStatus DecodeThumbBCCTargetOperand(llvm::MCInst &Inst,unsigned Val,
290                                 uint64_t Address, const void *Decoder);
291 static DecodeStatus DecodeThumbBLTargetOperand(llvm::MCInst &Inst, unsigned Val,
292                                 uint64_t Address, const void *Decoder);
293 static DecodeStatus DecodeIT(llvm::MCInst &Inst, unsigned Val,
294                                 uint64_t Address, const void *Decoder);
295 
296 #include "ARMGenDisassemblerTables.inc"
297 #include "ARMGenInstrInfo.inc"
298 #include "ARMGenEDInfo.inc"
299 
300 static MCDisassembler *createARMDisassembler(const Target &T, const MCSubtargetInfo &STI) {
301   return new ARMDisassembler(STI);
302 }
303 
304 static MCDisassembler *createThumbDisassembler(const Target &T, const MCSubtargetInfo &STI) {
305   return new ThumbDisassembler(STI);
306 }
307 
308 EDInstInfo *ARMDisassembler::getEDInfo() const {
309   return instInfoARM;
310 }
311 
312 EDInstInfo *ThumbDisassembler::getEDInfo() const {
313   return instInfoARM;
314 }
315 
316 DecodeStatus ARMDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
317                                              const MemoryObject &Region,
318                                              uint64_t Address,
319                                              raw_ostream &os) const {
320   uint8_t bytes[4];
321 
322   // We want to read exactly 4 bytes of data.
323   if (Region.readBytes(Address, 4, (uint8_t*)bytes, NULL) == -1) {
324     Size = 0;
325     return MCDisassembler::Fail;
326   }
327 
328   // Encoded as a small-endian 32-bit word in the stream.
329   uint32_t insn = (bytes[3] << 24) |
330                   (bytes[2] << 16) |
331                   (bytes[1] <<  8) |
332                   (bytes[0] <<  0);
333 
334   // Calling the auto-generated decoder function.
335   DecodeStatus result = decodeARMInstruction32(MI, insn, Address, this);
336   if (result != MCDisassembler::Fail) {
337     Size = 4;
338     return result;
339   }
340 
341   // Instructions that are shared between ARM and Thumb modes.
342   // FIXME: This shouldn't really exist.  It's an artifact of the
343   // fact that we fail to encode a few instructions properly for Thumb.
344   MI.clear();
345   result = decodeCommonInstruction32(MI, insn, Address, this);
346   if (result != MCDisassembler::Fail) {
347     Size = 4;
348     return result;
349   }
350 
351   // VFP and NEON instructions, similarly, are shared between ARM
352   // and Thumb modes.
353   MI.clear();
354   result = decodeVFPInstruction32(MI, insn, Address, this);
355   if (result != MCDisassembler::Fail) {
356     Size = 4;
357     return result;
358   }
359 
360   MI.clear();
361   result = decodeNEONDataInstruction32(MI, insn, Address, this);
362   if (result != MCDisassembler::Fail) {
363     Size = 4;
364     // Add a fake predicate operand, because we share these instruction
365     // definitions with Thumb2 where these instructions are predicable.
366     if (!DecodePredicateOperand(MI, 0xE, Address, this))
367       return MCDisassembler::Fail;
368     return result;
369   }
370 
371   MI.clear();
372   result = decodeNEONLoadStoreInstruction32(MI, insn, Address, this);
373   if (result != MCDisassembler::Fail) {
374     Size = 4;
375     // Add a fake predicate operand, because we share these instruction
376     // definitions with Thumb2 where these instructions are predicable.
377     if (!DecodePredicateOperand(MI, 0xE, Address, this))
378       return MCDisassembler::Fail;
379     return result;
380   }
381 
382   MI.clear();
383   result = decodeNEONDupInstruction32(MI, insn, Address, this);
384   if (result != MCDisassembler::Fail) {
385     Size = 4;
386     // Add a fake predicate operand, because we share these instruction
387     // definitions with Thumb2 where these instructions are predicable.
388     if (!DecodePredicateOperand(MI, 0xE, Address, this))
389       return MCDisassembler::Fail;
390     return result;
391   }
392 
393   MI.clear();
394 
395   Size = 0;
396   return MCDisassembler::Fail;
397 }
398 
399 namespace llvm {
400 extern MCInstrDesc ARMInsts[];
401 }
402 
403 // Thumb1 instructions don't have explicit S bits.  Rather, they
404 // implicitly set CPSR.  Since it's not represented in the encoding, the
405 // auto-generated decoder won't inject the CPSR operand.  We need to fix
406 // that as a post-pass.
407 static void AddThumb1SBit(MCInst &MI, bool InITBlock) {
408   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
409   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
410   MCInst::iterator I = MI.begin();
411   for (unsigned i = 0; i < NumOps; ++i, ++I) {
412     if (I == MI.end()) break;
413     if (OpInfo[i].isOptionalDef() && OpInfo[i].RegClass == ARM::CCRRegClassID) {
414       if (i > 0 && OpInfo[i-1].isPredicate()) continue;
415       MI.insert(I, MCOperand::CreateReg(InITBlock ? 0 : ARM::CPSR));
416       return;
417     }
418   }
419 
420   MI.insert(I, MCOperand::CreateReg(InITBlock ? 0 : ARM::CPSR));
421 }
422 
423 // Most Thumb instructions don't have explicit predicates in the
424 // encoding, but rather get their predicates from IT context.  We need
425 // to fix up the predicate operands using this context information as a
426 // post-pass.
427 void ThumbDisassembler::AddThumbPredicate(MCInst &MI) const {
428   // A few instructions actually have predicates encoded in them.  Don't
429   // try to overwrite it if we're seeing one of those.
430   switch (MI.getOpcode()) {
431     case ARM::tBcc:
432     case ARM::t2Bcc:
433       return;
434     default:
435       break;
436   }
437 
438   // If we're in an IT block, base the predicate on that.  Otherwise,
439   // assume a predicate of AL.
440   unsigned CC;
441   if (!ITBlock.empty()) {
442     CC = ITBlock.back();
443     if (CC == 0xF)
444       CC = ARMCC::AL;
445     ITBlock.pop_back();
446   } else
447     CC = ARMCC::AL;
448 
449   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
450   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
451   MCInst::iterator I = MI.begin();
452   for (unsigned i = 0; i < NumOps; ++i, ++I) {
453     if (I == MI.end()) break;
454     if (OpInfo[i].isPredicate()) {
455       I = MI.insert(I, MCOperand::CreateImm(CC));
456       ++I;
457       if (CC == ARMCC::AL)
458         MI.insert(I, MCOperand::CreateReg(0));
459       else
460         MI.insert(I, MCOperand::CreateReg(ARM::CPSR));
461       return;
462     }
463   }
464 
465   I = MI.insert(I, MCOperand::CreateImm(CC));
466   ++I;
467   if (CC == ARMCC::AL)
468     MI.insert(I, MCOperand::CreateReg(0));
469   else
470     MI.insert(I, MCOperand::CreateReg(ARM::CPSR));
471 }
472 
473 // Thumb VFP instructions are a special case.  Because we share their
474 // encodings between ARM and Thumb modes, and they are predicable in ARM
475 // mode, the auto-generated decoder will give them an (incorrect)
476 // predicate operand.  We need to rewrite these operands based on the IT
477 // context as a post-pass.
478 void ThumbDisassembler::UpdateThumbVFPPredicate(MCInst &MI) const {
479   unsigned CC;
480   if (!ITBlock.empty()) {
481     CC = ITBlock.back();
482     ITBlock.pop_back();
483   } else
484     CC = ARMCC::AL;
485 
486   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
487   MCInst::iterator I = MI.begin();
488   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
489   for (unsigned i = 0; i < NumOps; ++i, ++I) {
490     if (OpInfo[i].isPredicate() ) {
491       I->setImm(CC);
492       ++I;
493       if (CC == ARMCC::AL)
494         I->setReg(0);
495       else
496         I->setReg(ARM::CPSR);
497       return;
498     }
499   }
500 }
501 
502 DecodeStatus ThumbDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
503                                                const MemoryObject &Region,
504                                                uint64_t Address,
505                                                raw_ostream &os) const {
506   uint8_t bytes[4];
507 
508   // We want to read exactly 2 bytes of data.
509   if (Region.readBytes(Address, 2, (uint8_t*)bytes, NULL) == -1) {
510     Size = 0;
511     return MCDisassembler::Fail;
512   }
513 
514   uint16_t insn16 = (bytes[1] << 8) | bytes[0];
515   DecodeStatus result = decodeThumbInstruction16(MI, insn16, Address, this);
516   if (result != MCDisassembler::Fail) {
517     Size = 2;
518     AddThumbPredicate(MI);
519     return result;
520   }
521 
522   MI.clear();
523   result = decodeThumbSBitInstruction16(MI, insn16, Address, this);
524   if (result) {
525     Size = 2;
526     bool InITBlock = !ITBlock.empty();
527     AddThumbPredicate(MI);
528     AddThumb1SBit(MI, InITBlock);
529     return result;
530   }
531 
532   MI.clear();
533   result = decodeThumb2Instruction16(MI, insn16, Address, this);
534   if (result != MCDisassembler::Fail) {
535     Size = 2;
536     AddThumbPredicate(MI);
537 
538     // If we find an IT instruction, we need to parse its condition
539     // code and mask operands so that we can apply them correctly
540     // to the subsequent instructions.
541     if (MI.getOpcode() == ARM::t2IT) {
542       // (3 - the number of trailing zeros) is the number of then / else.
543       unsigned firstcond = MI.getOperand(0).getImm();
544       unsigned Mask = MI.getOperand(1).getImm();
545       unsigned CondBit0 = Mask >> 4 & 1;
546       unsigned NumTZ = CountTrailingZeros_32(Mask);
547       assert(NumTZ <= 3 && "Invalid IT mask!");
548       for (unsigned Pos = 3, e = NumTZ; Pos > e; --Pos) {
549         bool T = ((Mask >> Pos) & 1) == CondBit0;
550         if (T)
551           ITBlock.insert(ITBlock.begin(), firstcond);
552         else
553           ITBlock.insert(ITBlock.begin(), firstcond ^ 1);
554       }
555 
556       ITBlock.push_back(firstcond);
557     }
558 
559     return result;
560   }
561 
562   // We want to read exactly 4 bytes of data.
563   if (Region.readBytes(Address, 4, (uint8_t*)bytes, NULL) == -1) {
564     Size = 0;
565     return MCDisassembler::Fail;
566   }
567 
568   uint32_t insn32 = (bytes[3] <<  8) |
569                     (bytes[2] <<  0) |
570                     (bytes[1] << 24) |
571                     (bytes[0] << 16);
572   MI.clear();
573   result = decodeThumbInstruction32(MI, insn32, Address, this);
574   if (result != MCDisassembler::Fail) {
575     Size = 4;
576     bool InITBlock = ITBlock.size();
577     AddThumbPredicate(MI);
578     AddThumb1SBit(MI, InITBlock);
579     return result;
580   }
581 
582   MI.clear();
583   result = decodeThumb2Instruction32(MI, insn32, Address, this);
584   if (result != MCDisassembler::Fail) {
585     Size = 4;
586     AddThumbPredicate(MI);
587     return result;
588   }
589 
590   MI.clear();
591   result = decodeCommonInstruction32(MI, insn32, Address, this);
592   if (result != MCDisassembler::Fail) {
593     Size = 4;
594     AddThumbPredicate(MI);
595     return result;
596   }
597 
598   MI.clear();
599   result = decodeVFPInstruction32(MI, insn32, Address, this);
600   if (result != MCDisassembler::Fail) {
601     Size = 4;
602     UpdateThumbVFPPredicate(MI);
603     return result;
604   }
605 
606   MI.clear();
607   result = decodeNEONDupInstruction32(MI, insn32, Address, this);
608   if (result != MCDisassembler::Fail) {
609     Size = 4;
610     AddThumbPredicate(MI);
611     return result;
612   }
613 
614   if (fieldFromInstruction32(insn32, 24, 8) == 0xF9) {
615     MI.clear();
616     uint32_t NEONLdStInsn = insn32;
617     NEONLdStInsn &= 0xF0FFFFFF;
618     NEONLdStInsn |= 0x04000000;
619     result = decodeNEONLoadStoreInstruction32(MI, NEONLdStInsn, Address, this);
620     if (result != MCDisassembler::Fail) {
621       Size = 4;
622       AddThumbPredicate(MI);
623       return result;
624     }
625   }
626 
627   if (fieldFromInstruction32(insn32, 24, 4) == 0xF) {
628     MI.clear();
629     uint32_t NEONDataInsn = insn32;
630     NEONDataInsn &= 0xF0FFFFFF; // Clear bits 27-24
631     NEONDataInsn |= (NEONDataInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
632     NEONDataInsn |= 0x12000000; // Set bits 28 and 25
633     result = decodeNEONDataInstruction32(MI, NEONDataInsn, Address, this);
634     if (result != MCDisassembler::Fail) {
635       Size = 4;
636       AddThumbPredicate(MI);
637       return result;
638     }
639   }
640 
641   Size = 0;
642   return MCDisassembler::Fail;
643 }
644 
645 
646 extern "C" void LLVMInitializeARMDisassembler() {
647   TargetRegistry::RegisterMCDisassembler(TheARMTarget,
648                                          createARMDisassembler);
649   TargetRegistry::RegisterMCDisassembler(TheThumbTarget,
650                                          createThumbDisassembler);
651 }
652 
653 static const unsigned GPRDecoderTable[] = {
654   ARM::R0, ARM::R1, ARM::R2, ARM::R3,
655   ARM::R4, ARM::R5, ARM::R6, ARM::R7,
656   ARM::R8, ARM::R9, ARM::R10, ARM::R11,
657   ARM::R12, ARM::SP, ARM::LR, ARM::PC
658 };
659 
660 static DecodeStatus DecodeGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
661                                    uint64_t Address, const void *Decoder) {
662   if (RegNo > 15)
663     return MCDisassembler::Fail;
664 
665   unsigned Register = GPRDecoderTable[RegNo];
666   Inst.addOperand(MCOperand::CreateReg(Register));
667   return MCDisassembler::Success;
668 }
669 
670 static DecodeStatus
671 DecodeGPRnopcRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
672                            uint64_t Address, const void *Decoder) {
673   if (RegNo == 15) return MCDisassembler::Fail;
674   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
675 }
676 
677 static DecodeStatus DecodetGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
678                                    uint64_t Address, const void *Decoder) {
679   if (RegNo > 7)
680     return MCDisassembler::Fail;
681   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
682 }
683 
684 static DecodeStatus DecodetcGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
685                                    uint64_t Address, const void *Decoder) {
686   unsigned Register = 0;
687   switch (RegNo) {
688     case 0:
689       Register = ARM::R0;
690       break;
691     case 1:
692       Register = ARM::R1;
693       break;
694     case 2:
695       Register = ARM::R2;
696       break;
697     case 3:
698       Register = ARM::R3;
699       break;
700     case 9:
701       Register = ARM::R9;
702       break;
703     case 12:
704       Register = ARM::R12;
705       break;
706     default:
707       return MCDisassembler::Fail;
708     }
709 
710   Inst.addOperand(MCOperand::CreateReg(Register));
711   return MCDisassembler::Success;
712 }
713 
714 static DecodeStatus DecoderGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
715                                    uint64_t Address, const void *Decoder) {
716   if (RegNo == 13 || RegNo == 15) return MCDisassembler::Fail;
717   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
718 }
719 
720 static const unsigned SPRDecoderTable[] = {
721      ARM::S0,  ARM::S1,  ARM::S2,  ARM::S3,
722      ARM::S4,  ARM::S5,  ARM::S6,  ARM::S7,
723      ARM::S8,  ARM::S9, ARM::S10, ARM::S11,
724     ARM::S12, ARM::S13, ARM::S14, ARM::S15,
725     ARM::S16, ARM::S17, ARM::S18, ARM::S19,
726     ARM::S20, ARM::S21, ARM::S22, ARM::S23,
727     ARM::S24, ARM::S25, ARM::S26, ARM::S27,
728     ARM::S28, ARM::S29, ARM::S30, ARM::S31
729 };
730 
731 static DecodeStatus DecodeSPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
732                                    uint64_t Address, const void *Decoder) {
733   if (RegNo > 31)
734     return MCDisassembler::Fail;
735 
736   unsigned Register = SPRDecoderTable[RegNo];
737   Inst.addOperand(MCOperand::CreateReg(Register));
738   return MCDisassembler::Success;
739 }
740 
741 static const unsigned DPRDecoderTable[] = {
742      ARM::D0,  ARM::D1,  ARM::D2,  ARM::D3,
743      ARM::D4,  ARM::D5,  ARM::D6,  ARM::D7,
744      ARM::D8,  ARM::D9, ARM::D10, ARM::D11,
745     ARM::D12, ARM::D13, ARM::D14, ARM::D15,
746     ARM::D16, ARM::D17, ARM::D18, ARM::D19,
747     ARM::D20, ARM::D21, ARM::D22, ARM::D23,
748     ARM::D24, ARM::D25, ARM::D26, ARM::D27,
749     ARM::D28, ARM::D29, ARM::D30, ARM::D31
750 };
751 
752 static DecodeStatus DecodeDPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
753                                    uint64_t Address, const void *Decoder) {
754   if (RegNo > 31)
755     return MCDisassembler::Fail;
756 
757   unsigned Register = DPRDecoderTable[RegNo];
758   Inst.addOperand(MCOperand::CreateReg(Register));
759   return MCDisassembler::Success;
760 }
761 
762 static DecodeStatus DecodeDPR_8RegisterClass(llvm::MCInst &Inst, unsigned RegNo,
763                                    uint64_t Address, const void *Decoder) {
764   if (RegNo > 7)
765     return MCDisassembler::Fail;
766   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
767 }
768 
769 static DecodeStatus
770 DecodeDPR_VFP2RegisterClass(llvm::MCInst &Inst, unsigned RegNo,
771                             uint64_t Address, const void *Decoder) {
772   if (RegNo > 15)
773     return MCDisassembler::Fail;
774   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
775 }
776 
777 static const unsigned QPRDecoderTable[] = {
778      ARM::Q0,  ARM::Q1,  ARM::Q2,  ARM::Q3,
779      ARM::Q4,  ARM::Q5,  ARM::Q6,  ARM::Q7,
780      ARM::Q8,  ARM::Q9, ARM::Q10, ARM::Q11,
781     ARM::Q12, ARM::Q13, ARM::Q14, ARM::Q15
782 };
783 
784 
785 static DecodeStatus DecodeQPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
786                                    uint64_t Address, const void *Decoder) {
787   if (RegNo > 31)
788     return MCDisassembler::Fail;
789   RegNo >>= 1;
790 
791   unsigned Register = QPRDecoderTable[RegNo];
792   Inst.addOperand(MCOperand::CreateReg(Register));
793   return MCDisassembler::Success;
794 }
795 
796 static DecodeStatus DecodePredicateOperand(llvm::MCInst &Inst, unsigned Val,
797                                uint64_t Address, const void *Decoder) {
798   if (Val == 0xF) return MCDisassembler::Fail;
799   // AL predicate is not allowed on Thumb1 branches.
800   if (Inst.getOpcode() == ARM::tBcc && Val == 0xE)
801     return MCDisassembler::Fail;
802   Inst.addOperand(MCOperand::CreateImm(Val));
803   if (Val == ARMCC::AL) {
804     Inst.addOperand(MCOperand::CreateReg(0));
805   } else
806     Inst.addOperand(MCOperand::CreateReg(ARM::CPSR));
807   return MCDisassembler::Success;
808 }
809 
810 static DecodeStatus DecodeCCOutOperand(llvm::MCInst &Inst, unsigned Val,
811                                uint64_t Address, const void *Decoder) {
812   if (Val)
813     Inst.addOperand(MCOperand::CreateReg(ARM::CPSR));
814   else
815     Inst.addOperand(MCOperand::CreateReg(0));
816   return MCDisassembler::Success;
817 }
818 
819 static DecodeStatus DecodeSOImmOperand(llvm::MCInst &Inst, unsigned Val,
820                                uint64_t Address, const void *Decoder) {
821   uint32_t imm = Val & 0xFF;
822   uint32_t rot = (Val & 0xF00) >> 7;
823   uint32_t rot_imm = (imm >> rot) | (imm << (32-rot));
824   Inst.addOperand(MCOperand::CreateImm(rot_imm));
825   return MCDisassembler::Success;
826 }
827 
828 static DecodeStatus DecodeSORegImmOperand(llvm::MCInst &Inst, unsigned Val,
829                                uint64_t Address, const void *Decoder) {
830   DecodeStatus S = MCDisassembler::Success;
831 
832   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
833   unsigned type = fieldFromInstruction32(Val, 5, 2);
834   unsigned imm = fieldFromInstruction32(Val, 7, 5);
835 
836   // Register-immediate
837   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
838     return MCDisassembler::Fail;
839 
840   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
841   switch (type) {
842     case 0:
843       Shift = ARM_AM::lsl;
844       break;
845     case 1:
846       Shift = ARM_AM::lsr;
847       break;
848     case 2:
849       Shift = ARM_AM::asr;
850       break;
851     case 3:
852       Shift = ARM_AM::ror;
853       break;
854   }
855 
856   if (Shift == ARM_AM::ror && imm == 0)
857     Shift = ARM_AM::rrx;
858 
859   unsigned Op = Shift | (imm << 3);
860   Inst.addOperand(MCOperand::CreateImm(Op));
861 
862   return S;
863 }
864 
865 static DecodeStatus DecodeSORegRegOperand(llvm::MCInst &Inst, unsigned Val,
866                                uint64_t Address, const void *Decoder) {
867   DecodeStatus S = MCDisassembler::Success;
868 
869   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
870   unsigned type = fieldFromInstruction32(Val, 5, 2);
871   unsigned Rs = fieldFromInstruction32(Val, 8, 4);
872 
873   // Register-register
874   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
875     return MCDisassembler::Fail;
876   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rs, Address, Decoder)))
877     return MCDisassembler::Fail;
878 
879   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
880   switch (type) {
881     case 0:
882       Shift = ARM_AM::lsl;
883       break;
884     case 1:
885       Shift = ARM_AM::lsr;
886       break;
887     case 2:
888       Shift = ARM_AM::asr;
889       break;
890     case 3:
891       Shift = ARM_AM::ror;
892       break;
893   }
894 
895   Inst.addOperand(MCOperand::CreateImm(Shift));
896 
897   return S;
898 }
899 
900 static DecodeStatus DecodeRegListOperand(llvm::MCInst &Inst, unsigned Val,
901                                  uint64_t Address, const void *Decoder) {
902   DecodeStatus S = MCDisassembler::Success;
903 
904   // Empty register lists are not allowed.
905   if (CountPopulation_32(Val) == 0) return MCDisassembler::Fail;
906   for (unsigned i = 0; i < 16; ++i) {
907     if (Val & (1 << i)) {
908       if (!Check(S, DecodeGPRRegisterClass(Inst, i, Address, Decoder)))
909         return MCDisassembler::Fail;
910     }
911   }
912 
913   return S;
914 }
915 
916 static DecodeStatus DecodeSPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
917                                  uint64_t Address, const void *Decoder) {
918   DecodeStatus S = MCDisassembler::Success;
919 
920   unsigned Vd = fieldFromInstruction32(Val, 8, 4);
921   unsigned regs = Val & 0xFF;
922 
923   if (!Check(S, DecodeSPRRegisterClass(Inst, Vd, Address, Decoder)))
924     return MCDisassembler::Fail;
925   for (unsigned i = 0; i < (regs - 1); ++i) {
926     if (!Check(S, DecodeSPRRegisterClass(Inst, ++Vd, Address, Decoder)))
927       return MCDisassembler::Fail;
928   }
929 
930   return S;
931 }
932 
933 static DecodeStatus DecodeDPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
934                                  uint64_t Address, const void *Decoder) {
935   DecodeStatus S = MCDisassembler::Success;
936 
937   unsigned Vd = fieldFromInstruction32(Val, 8, 4);
938   unsigned regs = (Val & 0xFF) / 2;
939 
940   if (!Check(S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)))
941       return MCDisassembler::Fail;
942   for (unsigned i = 0; i < (regs - 1); ++i) {
943     if (!Check(S, DecodeDPRRegisterClass(Inst, ++Vd, Address, Decoder)))
944       return MCDisassembler::Fail;
945   }
946 
947   return S;
948 }
949 
950 static DecodeStatus DecodeBitfieldMaskOperand(llvm::MCInst &Inst, unsigned Val,
951                                       uint64_t Address, const void *Decoder) {
952   // This operand encodes a mask of contiguous zeros between a specified MSB
953   // and LSB.  To decode it, we create the mask of all bits MSB-and-lower,
954   // the mask of all bits LSB-and-lower, and then xor them to create
955   // the mask of that's all ones on [msb, lsb].  Finally we not it to
956   // create the final mask.
957   unsigned msb = fieldFromInstruction32(Val, 5, 5);
958   unsigned lsb = fieldFromInstruction32(Val, 0, 5);
959   uint32_t msb_mask = (1 << (msb+1)) - 1;
960   uint32_t lsb_mask = (1 << lsb) - 1;
961   Inst.addOperand(MCOperand::CreateImm(~(msb_mask ^ lsb_mask)));
962   return MCDisassembler::Success;
963 }
964 
965 static DecodeStatus DecodeCopMemInstruction(llvm::MCInst &Inst, unsigned Insn,
966                                   uint64_t Address, const void *Decoder) {
967   DecodeStatus S = MCDisassembler::Success;
968 
969   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
970   unsigned CRd = fieldFromInstruction32(Insn, 12, 4);
971   unsigned coproc = fieldFromInstruction32(Insn, 8, 4);
972   unsigned imm = fieldFromInstruction32(Insn, 0, 8);
973   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
974   unsigned U = fieldFromInstruction32(Insn, 23, 1);
975 
976   switch (Inst.getOpcode()) {
977     case ARM::LDC_OFFSET:
978     case ARM::LDC_PRE:
979     case ARM::LDC_POST:
980     case ARM::LDC_OPTION:
981     case ARM::LDCL_OFFSET:
982     case ARM::LDCL_PRE:
983     case ARM::LDCL_POST:
984     case ARM::LDCL_OPTION:
985     case ARM::STC_OFFSET:
986     case ARM::STC_PRE:
987     case ARM::STC_POST:
988     case ARM::STC_OPTION:
989     case ARM::STCL_OFFSET:
990     case ARM::STCL_PRE:
991     case ARM::STCL_POST:
992     case ARM::STCL_OPTION:
993       if (coproc == 0xA || coproc == 0xB)
994         return MCDisassembler::Fail;
995       break;
996     default:
997       break;
998   }
999 
1000   Inst.addOperand(MCOperand::CreateImm(coproc));
1001   Inst.addOperand(MCOperand::CreateImm(CRd));
1002   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1003     return MCDisassembler::Fail;
1004   switch (Inst.getOpcode()) {
1005     case ARM::LDC_OPTION:
1006     case ARM::LDCL_OPTION:
1007     case ARM::LDC2_OPTION:
1008     case ARM::LDC2L_OPTION:
1009     case ARM::STC_OPTION:
1010     case ARM::STCL_OPTION:
1011     case ARM::STC2_OPTION:
1012     case ARM::STC2L_OPTION:
1013     case ARM::LDCL_POST:
1014     case ARM::STCL_POST:
1015     case ARM::LDC2L_POST:
1016     case ARM::STC2L_POST:
1017       break;
1018     default:
1019       Inst.addOperand(MCOperand::CreateReg(0));
1020       break;
1021   }
1022 
1023   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1024   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1025 
1026   bool writeback = (P == 0) || (W == 1);
1027   unsigned idx_mode = 0;
1028   if (P && writeback)
1029     idx_mode = ARMII::IndexModePre;
1030   else if (!P && writeback)
1031     idx_mode = ARMII::IndexModePost;
1032 
1033   switch (Inst.getOpcode()) {
1034     case ARM::LDCL_POST:
1035     case ARM::STCL_POST:
1036     case ARM::LDC2L_POST:
1037     case ARM::STC2L_POST:
1038       imm |= U << 8;
1039     case ARM::LDC_OPTION:
1040     case ARM::LDCL_OPTION:
1041     case ARM::LDC2_OPTION:
1042     case ARM::LDC2L_OPTION:
1043     case ARM::STC_OPTION:
1044     case ARM::STCL_OPTION:
1045     case ARM::STC2_OPTION:
1046     case ARM::STC2L_OPTION:
1047       Inst.addOperand(MCOperand::CreateImm(imm));
1048       break;
1049     default:
1050       if (U)
1051         Inst.addOperand(MCOperand::CreateImm(
1052             ARM_AM::getAM2Opc(ARM_AM::add, imm, ARM_AM::lsl, idx_mode)));
1053       else
1054         Inst.addOperand(MCOperand::CreateImm(
1055             ARM_AM::getAM2Opc(ARM_AM::sub, imm, ARM_AM::lsl, idx_mode)));
1056       break;
1057   }
1058 
1059   switch (Inst.getOpcode()) {
1060     case ARM::LDC_OFFSET:
1061     case ARM::LDC_PRE:
1062     case ARM::LDC_POST:
1063     case ARM::LDC_OPTION:
1064     case ARM::LDCL_OFFSET:
1065     case ARM::LDCL_PRE:
1066     case ARM::LDCL_POST:
1067     case ARM::LDCL_OPTION:
1068     case ARM::STC_OFFSET:
1069     case ARM::STC_PRE:
1070     case ARM::STC_POST:
1071     case ARM::STC_OPTION:
1072     case ARM::STCL_OFFSET:
1073     case ARM::STCL_PRE:
1074     case ARM::STCL_POST:
1075     case ARM::STCL_OPTION:
1076       if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1077         return MCDisassembler::Fail;
1078       break;
1079     default:
1080       break;
1081   }
1082 
1083   return S;
1084 }
1085 
1086 static DecodeStatus
1087 DecodeAddrMode2IdxInstruction(llvm::MCInst &Inst, unsigned Insn,
1088                               uint64_t Address, const void *Decoder) {
1089   DecodeStatus S = MCDisassembler::Success;
1090 
1091   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1092   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
1093   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1094   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
1095   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1096   unsigned reg = fieldFromInstruction32(Insn, 25, 1);
1097   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1098   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1099 
1100   // On stores, the writeback operand precedes Rt.
1101   switch (Inst.getOpcode()) {
1102     case ARM::STR_POST_IMM:
1103     case ARM::STR_POST_REG:
1104     case ARM::STRB_POST_IMM:
1105     case ARM::STRB_POST_REG:
1106     case ARM::STRT_POST_REG:
1107     case ARM::STRT_POST_IMM:
1108     case ARM::STRBT_POST_REG:
1109     case ARM::STRBT_POST_IMM:
1110       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1111         return MCDisassembler::Fail;
1112       break;
1113     default:
1114       break;
1115   }
1116 
1117   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
1118     return MCDisassembler::Fail;
1119 
1120   // On loads, the writeback operand comes after Rt.
1121   switch (Inst.getOpcode()) {
1122     case ARM::LDR_POST_IMM:
1123     case ARM::LDR_POST_REG:
1124     case ARM::LDRB_POST_IMM:
1125     case ARM::LDRB_POST_REG:
1126     case ARM::LDRBT_POST_REG:
1127     case ARM::LDRBT_POST_IMM:
1128     case ARM::LDRT_POST_REG:
1129     case ARM::LDRT_POST_IMM:
1130       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1131         return MCDisassembler::Fail;
1132       break;
1133     default:
1134       break;
1135   }
1136 
1137   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1138     return MCDisassembler::Fail;
1139 
1140   ARM_AM::AddrOpc Op = ARM_AM::add;
1141   if (!fieldFromInstruction32(Insn, 23, 1))
1142     Op = ARM_AM::sub;
1143 
1144   bool writeback = (P == 0) || (W == 1);
1145   unsigned idx_mode = 0;
1146   if (P && writeback)
1147     idx_mode = ARMII::IndexModePre;
1148   else if (!P && writeback)
1149     idx_mode = ARMII::IndexModePost;
1150 
1151   if (writeback && (Rn == 15 || Rn == Rt))
1152     S = MCDisassembler::SoftFail; // UNPREDICTABLE
1153 
1154   if (reg) {
1155     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1156       return MCDisassembler::Fail;
1157     ARM_AM::ShiftOpc Opc = ARM_AM::lsl;
1158     switch( fieldFromInstruction32(Insn, 5, 2)) {
1159       case 0:
1160         Opc = ARM_AM::lsl;
1161         break;
1162       case 1:
1163         Opc = ARM_AM::lsr;
1164         break;
1165       case 2:
1166         Opc = ARM_AM::asr;
1167         break;
1168       case 3:
1169         Opc = ARM_AM::ror;
1170         break;
1171       default:
1172         return MCDisassembler::Fail;
1173     }
1174     unsigned amt = fieldFromInstruction32(Insn, 7, 5);
1175     unsigned imm = ARM_AM::getAM2Opc(Op, amt, Opc, idx_mode);
1176 
1177     Inst.addOperand(MCOperand::CreateImm(imm));
1178   } else {
1179     Inst.addOperand(MCOperand::CreateReg(0));
1180     unsigned tmp = ARM_AM::getAM2Opc(Op, imm, ARM_AM::lsl, idx_mode);
1181     Inst.addOperand(MCOperand::CreateImm(tmp));
1182   }
1183 
1184   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1185     return MCDisassembler::Fail;
1186 
1187   return S;
1188 }
1189 
1190 static DecodeStatus DecodeSORegMemOperand(llvm::MCInst &Inst, unsigned Val,
1191                                   uint64_t Address, const void *Decoder) {
1192   DecodeStatus S = MCDisassembler::Success;
1193 
1194   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
1195   unsigned Rm = fieldFromInstruction32(Val,  0, 4);
1196   unsigned type = fieldFromInstruction32(Val, 5, 2);
1197   unsigned imm = fieldFromInstruction32(Val, 7, 5);
1198   unsigned U = fieldFromInstruction32(Val, 12, 1);
1199 
1200   ARM_AM::ShiftOpc ShOp = ARM_AM::lsl;
1201   switch (type) {
1202     case 0:
1203       ShOp = ARM_AM::lsl;
1204       break;
1205     case 1:
1206       ShOp = ARM_AM::lsr;
1207       break;
1208     case 2:
1209       ShOp = ARM_AM::asr;
1210       break;
1211     case 3:
1212       ShOp = ARM_AM::ror;
1213       break;
1214   }
1215 
1216   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1217     return MCDisassembler::Fail;
1218   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1219     return MCDisassembler::Fail;
1220   unsigned shift;
1221   if (U)
1222     shift = ARM_AM::getAM2Opc(ARM_AM::add, imm, ShOp);
1223   else
1224     shift = ARM_AM::getAM2Opc(ARM_AM::sub, imm, ShOp);
1225   Inst.addOperand(MCOperand::CreateImm(shift));
1226 
1227   return S;
1228 }
1229 
1230 static DecodeStatus
1231 DecodeAddrMode3Instruction(llvm::MCInst &Inst, unsigned Insn,
1232                            uint64_t Address, const void *Decoder) {
1233   DecodeStatus S = MCDisassembler::Success;
1234 
1235   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
1236   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1237   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1238   unsigned type = fieldFromInstruction32(Insn, 22, 1);
1239   unsigned imm = fieldFromInstruction32(Insn, 8, 4);
1240   unsigned U = ((~fieldFromInstruction32(Insn, 23, 1)) & 1) << 8;
1241   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1242   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1243   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1244 
1245   bool writeback = (W == 1) | (P == 0);
1246 
1247   // For {LD,ST}RD, Rt must be even, else undefined.
1248   switch (Inst.getOpcode()) {
1249     case ARM::STRD:
1250     case ARM::STRD_PRE:
1251     case ARM::STRD_POST:
1252     case ARM::LDRD:
1253     case ARM::LDRD_PRE:
1254     case ARM::LDRD_POST:
1255       if (Rt & 0x1) return MCDisassembler::Fail;
1256       break;
1257     default:
1258       break;
1259   }
1260 
1261   if (writeback) { // Writeback
1262     if (P)
1263       U |= ARMII::IndexModePre << 9;
1264     else
1265       U |= ARMII::IndexModePost << 9;
1266 
1267     // On stores, the writeback operand precedes Rt.
1268     switch (Inst.getOpcode()) {
1269     case ARM::STRD:
1270     case ARM::STRD_PRE:
1271     case ARM::STRD_POST:
1272     case ARM::STRH:
1273     case ARM::STRH_PRE:
1274     case ARM::STRH_POST:
1275       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1276         return MCDisassembler::Fail;
1277       break;
1278     default:
1279       break;
1280     }
1281   }
1282 
1283   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
1284     return MCDisassembler::Fail;
1285   switch (Inst.getOpcode()) {
1286     case ARM::STRD:
1287     case ARM::STRD_PRE:
1288     case ARM::STRD_POST:
1289     case ARM::LDRD:
1290     case ARM::LDRD_PRE:
1291     case ARM::LDRD_POST:
1292       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
1293         return MCDisassembler::Fail;
1294       break;
1295     default:
1296       break;
1297   }
1298 
1299   if (writeback) {
1300     // On loads, the writeback operand comes after Rt.
1301     switch (Inst.getOpcode()) {
1302     case ARM::LDRD:
1303     case ARM::LDRD_PRE:
1304     case ARM::LDRD_POST:
1305     case ARM::LDRH:
1306     case ARM::LDRH_PRE:
1307     case ARM::LDRH_POST:
1308     case ARM::LDRSH:
1309     case ARM::LDRSH_PRE:
1310     case ARM::LDRSH_POST:
1311     case ARM::LDRSB:
1312     case ARM::LDRSB_PRE:
1313     case ARM::LDRSB_POST:
1314     case ARM::LDRHTr:
1315     case ARM::LDRSBTr:
1316       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1317         return MCDisassembler::Fail;
1318       break;
1319     default:
1320       break;
1321     }
1322   }
1323 
1324   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1325     return MCDisassembler::Fail;
1326 
1327   if (type) {
1328     Inst.addOperand(MCOperand::CreateReg(0));
1329     Inst.addOperand(MCOperand::CreateImm(U | (imm << 4) | Rm));
1330   } else {
1331     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1332     return MCDisassembler::Fail;
1333     Inst.addOperand(MCOperand::CreateImm(U));
1334   }
1335 
1336   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1337     return MCDisassembler::Fail;
1338 
1339   return S;
1340 }
1341 
1342 static DecodeStatus DecodeRFEInstruction(llvm::MCInst &Inst, unsigned Insn,
1343                                  uint64_t Address, const void *Decoder) {
1344   DecodeStatus S = MCDisassembler::Success;
1345 
1346   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1347   unsigned mode = fieldFromInstruction32(Insn, 23, 2);
1348 
1349   switch (mode) {
1350     case 0:
1351       mode = ARM_AM::da;
1352       break;
1353     case 1:
1354       mode = ARM_AM::ia;
1355       break;
1356     case 2:
1357       mode = ARM_AM::db;
1358       break;
1359     case 3:
1360       mode = ARM_AM::ib;
1361       break;
1362   }
1363 
1364   Inst.addOperand(MCOperand::CreateImm(mode));
1365   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1366     return MCDisassembler::Fail;
1367 
1368   return S;
1369 }
1370 
1371 static DecodeStatus DecodeMemMultipleWritebackInstruction(llvm::MCInst &Inst,
1372                                   unsigned Insn,
1373                                   uint64_t Address, const void *Decoder) {
1374   DecodeStatus S = MCDisassembler::Success;
1375 
1376   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1377   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1378   unsigned reglist = fieldFromInstruction32(Insn, 0, 16);
1379 
1380   if (pred == 0xF) {
1381     switch (Inst.getOpcode()) {
1382       case ARM::LDMDA:
1383         Inst.setOpcode(ARM::RFEDA);
1384         break;
1385       case ARM::LDMDA_UPD:
1386         Inst.setOpcode(ARM::RFEDA_UPD);
1387         break;
1388       case ARM::LDMDB:
1389         Inst.setOpcode(ARM::RFEDB);
1390         break;
1391       case ARM::LDMDB_UPD:
1392         Inst.setOpcode(ARM::RFEDB_UPD);
1393         break;
1394       case ARM::LDMIA:
1395         Inst.setOpcode(ARM::RFEIA);
1396         break;
1397       case ARM::LDMIA_UPD:
1398         Inst.setOpcode(ARM::RFEIA_UPD);
1399         break;
1400       case ARM::LDMIB:
1401         Inst.setOpcode(ARM::RFEIB);
1402         break;
1403       case ARM::LDMIB_UPD:
1404         Inst.setOpcode(ARM::RFEIB_UPD);
1405         break;
1406       case ARM::STMDA:
1407         Inst.setOpcode(ARM::SRSDA);
1408         break;
1409       case ARM::STMDA_UPD:
1410         Inst.setOpcode(ARM::SRSDA_UPD);
1411         break;
1412       case ARM::STMDB:
1413         Inst.setOpcode(ARM::SRSDB);
1414         break;
1415       case ARM::STMDB_UPD:
1416         Inst.setOpcode(ARM::SRSDB_UPD);
1417         break;
1418       case ARM::STMIA:
1419         Inst.setOpcode(ARM::SRSIA);
1420         break;
1421       case ARM::STMIA_UPD:
1422         Inst.setOpcode(ARM::SRSIA_UPD);
1423         break;
1424       case ARM::STMIB:
1425         Inst.setOpcode(ARM::SRSIB);
1426         break;
1427       case ARM::STMIB_UPD:
1428         Inst.setOpcode(ARM::SRSIB_UPD);
1429         break;
1430       default:
1431         if (!Check(S, MCDisassembler::Fail)) return MCDisassembler::Fail;
1432     }
1433 
1434     // For stores (which become SRS's, the only operand is the mode.
1435     if (fieldFromInstruction32(Insn, 20, 1) == 0) {
1436       Inst.addOperand(
1437           MCOperand::CreateImm(fieldFromInstruction32(Insn, 0, 4)));
1438       return S;
1439     }
1440 
1441     return DecodeRFEInstruction(Inst, Insn, Address, Decoder);
1442   }
1443 
1444   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1445     return MCDisassembler::Fail;
1446   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1447     return MCDisassembler::Fail; // Tied
1448   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1449     return MCDisassembler::Fail;
1450   if (!Check(S, DecodeRegListOperand(Inst, reglist, Address, Decoder)))
1451     return MCDisassembler::Fail;
1452 
1453   return S;
1454 }
1455 
1456 static DecodeStatus DecodeCPSInstruction(llvm::MCInst &Inst, unsigned Insn,
1457                                  uint64_t Address, const void *Decoder) {
1458   unsigned imod = fieldFromInstruction32(Insn, 18, 2);
1459   unsigned M = fieldFromInstruction32(Insn, 17, 1);
1460   unsigned iflags = fieldFromInstruction32(Insn, 6, 3);
1461   unsigned mode = fieldFromInstruction32(Insn, 0, 5);
1462 
1463   DecodeStatus S = MCDisassembler::Success;
1464 
1465   // imod == '01' --> UNPREDICTABLE
1466   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
1467   // return failure here.  The '01' imod value is unprintable, so there's
1468   // nothing useful we could do even if we returned UNPREDICTABLE.
1469 
1470   if (imod == 1) return MCDisassembler::Fail;
1471 
1472   if (imod && M) {
1473     Inst.setOpcode(ARM::CPS3p);
1474     Inst.addOperand(MCOperand::CreateImm(imod));
1475     Inst.addOperand(MCOperand::CreateImm(iflags));
1476     Inst.addOperand(MCOperand::CreateImm(mode));
1477   } else if (imod && !M) {
1478     Inst.setOpcode(ARM::CPS2p);
1479     Inst.addOperand(MCOperand::CreateImm(imod));
1480     Inst.addOperand(MCOperand::CreateImm(iflags));
1481     if (mode) S = MCDisassembler::SoftFail;
1482   } else if (!imod && M) {
1483     Inst.setOpcode(ARM::CPS1p);
1484     Inst.addOperand(MCOperand::CreateImm(mode));
1485     if (iflags) S = MCDisassembler::SoftFail;
1486   } else {
1487     // imod == '00' && M == '0' --> UNPREDICTABLE
1488     Inst.setOpcode(ARM::CPS1p);
1489     Inst.addOperand(MCOperand::CreateImm(mode));
1490     S = MCDisassembler::SoftFail;
1491   }
1492 
1493   return S;
1494 }
1495 
1496 static DecodeStatus DecodeT2CPSInstruction(llvm::MCInst &Inst, unsigned Insn,
1497                                  uint64_t Address, const void *Decoder) {
1498   unsigned imod = fieldFromInstruction32(Insn, 9, 2);
1499   unsigned M = fieldFromInstruction32(Insn, 8, 1);
1500   unsigned iflags = fieldFromInstruction32(Insn, 5, 3);
1501   unsigned mode = fieldFromInstruction32(Insn, 0, 5);
1502 
1503   DecodeStatus S = MCDisassembler::Success;
1504 
1505   // imod == '01' --> UNPREDICTABLE
1506   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
1507   // return failure here.  The '01' imod value is unprintable, so there's
1508   // nothing useful we could do even if we returned UNPREDICTABLE.
1509 
1510   if (imod == 1) return MCDisassembler::Fail;
1511 
1512   if (imod && M) {
1513     Inst.setOpcode(ARM::t2CPS3p);
1514     Inst.addOperand(MCOperand::CreateImm(imod));
1515     Inst.addOperand(MCOperand::CreateImm(iflags));
1516     Inst.addOperand(MCOperand::CreateImm(mode));
1517   } else if (imod && !M) {
1518     Inst.setOpcode(ARM::t2CPS2p);
1519     Inst.addOperand(MCOperand::CreateImm(imod));
1520     Inst.addOperand(MCOperand::CreateImm(iflags));
1521     if (mode) S = MCDisassembler::SoftFail;
1522   } else if (!imod && M) {
1523     Inst.setOpcode(ARM::t2CPS1p);
1524     Inst.addOperand(MCOperand::CreateImm(mode));
1525     if (iflags) S = MCDisassembler::SoftFail;
1526   } else {
1527     // imod == '00' && M == '0' --> UNPREDICTABLE
1528     Inst.setOpcode(ARM::t2CPS1p);
1529     Inst.addOperand(MCOperand::CreateImm(mode));
1530     S = MCDisassembler::SoftFail;
1531   }
1532 
1533   return S;
1534 }
1535 
1536 
1537 static DecodeStatus DecodeSMLAInstruction(llvm::MCInst &Inst, unsigned Insn,
1538                                  uint64_t Address, const void *Decoder) {
1539   DecodeStatus S = MCDisassembler::Success;
1540 
1541   unsigned Rd = fieldFromInstruction32(Insn, 16, 4);
1542   unsigned Rn = fieldFromInstruction32(Insn, 0, 4);
1543   unsigned Rm = fieldFromInstruction32(Insn, 8, 4);
1544   unsigned Ra = fieldFromInstruction32(Insn, 12, 4);
1545   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1546 
1547   if (pred == 0xF)
1548     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
1549 
1550   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
1551     return MCDisassembler::Fail;
1552   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
1553     return MCDisassembler::Fail;
1554   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1555     return MCDisassembler::Fail;
1556   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Ra, Address, Decoder)))
1557     return MCDisassembler::Fail;
1558 
1559   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1560     return MCDisassembler::Fail;
1561 
1562   return S;
1563 }
1564 
1565 static DecodeStatus DecodeAddrModeImm12Operand(llvm::MCInst &Inst, unsigned Val,
1566                            uint64_t Address, const void *Decoder) {
1567   DecodeStatus S = MCDisassembler::Success;
1568 
1569   unsigned add = fieldFromInstruction32(Val, 12, 1);
1570   unsigned imm = fieldFromInstruction32(Val, 0, 12);
1571   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
1572 
1573   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1574     return MCDisassembler::Fail;
1575 
1576   if (!add) imm *= -1;
1577   if (imm == 0 && !add) imm = INT32_MIN;
1578   Inst.addOperand(MCOperand::CreateImm(imm));
1579 
1580   return S;
1581 }
1582 
1583 static DecodeStatus DecodeAddrMode5Operand(llvm::MCInst &Inst, unsigned Val,
1584                                    uint64_t Address, const void *Decoder) {
1585   DecodeStatus S = MCDisassembler::Success;
1586 
1587   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
1588   unsigned U = fieldFromInstruction32(Val, 8, 1);
1589   unsigned imm = fieldFromInstruction32(Val, 0, 8);
1590 
1591   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1592     return MCDisassembler::Fail;
1593 
1594   if (U)
1595     Inst.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(ARM_AM::add, imm)));
1596   else
1597     Inst.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(ARM_AM::sub, imm)));
1598 
1599   return S;
1600 }
1601 
1602 static DecodeStatus DecodeAddrMode7Operand(llvm::MCInst &Inst, unsigned Val,
1603                                    uint64_t Address, const void *Decoder) {
1604   return DecodeGPRRegisterClass(Inst, Val, Address, Decoder);
1605 }
1606 
1607 static DecodeStatus
1608 DecodeBranchImmInstruction(llvm::MCInst &Inst, unsigned Insn,
1609                            uint64_t Address, const void *Decoder) {
1610   DecodeStatus S = MCDisassembler::Success;
1611 
1612   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1613   unsigned imm = fieldFromInstruction32(Insn, 0, 24) << 2;
1614 
1615   if (pred == 0xF) {
1616     Inst.setOpcode(ARM::BLXi);
1617     imm |= fieldFromInstruction32(Insn, 24, 1) << 1;
1618     Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(imm)));
1619     return S;
1620   }
1621 
1622   Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(imm)));
1623   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1624     return MCDisassembler::Fail;
1625 
1626   return S;
1627 }
1628 
1629 
1630 static DecodeStatus DecodeVCVTImmOperand(llvm::MCInst &Inst, unsigned Val,
1631                                  uint64_t Address, const void *Decoder) {
1632   Inst.addOperand(MCOperand::CreateImm(64 - Val));
1633   return MCDisassembler::Success;
1634 }
1635 
1636 static DecodeStatus DecodeAddrMode6Operand(llvm::MCInst &Inst, unsigned Val,
1637                                    uint64_t Address, const void *Decoder) {
1638   DecodeStatus S = MCDisassembler::Success;
1639 
1640   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
1641   unsigned align = fieldFromInstruction32(Val, 4, 2);
1642 
1643   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1644     return MCDisassembler::Fail;
1645   if (!align)
1646     Inst.addOperand(MCOperand::CreateImm(0));
1647   else
1648     Inst.addOperand(MCOperand::CreateImm(4 << align));
1649 
1650   return S;
1651 }
1652 
1653 static DecodeStatus DecodeVLDInstruction(llvm::MCInst &Inst, unsigned Insn,
1654                                    uint64_t Address, const void *Decoder) {
1655   DecodeStatus S = MCDisassembler::Success;
1656 
1657   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
1658   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
1659   unsigned wb = fieldFromInstruction32(Insn, 16, 4);
1660   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1661   Rn |= fieldFromInstruction32(Insn, 4, 2) << 4;
1662   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1663 
1664   // First output register
1665   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
1666     return MCDisassembler::Fail;
1667 
1668   // Second output register
1669   switch (Inst.getOpcode()) {
1670     case ARM::VLD1q8:
1671     case ARM::VLD1q16:
1672     case ARM::VLD1q32:
1673     case ARM::VLD1q64:
1674     case ARM::VLD1q8_UPD:
1675     case ARM::VLD1q16_UPD:
1676     case ARM::VLD1q32_UPD:
1677     case ARM::VLD1q64_UPD:
1678     case ARM::VLD1d8T:
1679     case ARM::VLD1d16T:
1680     case ARM::VLD1d32T:
1681     case ARM::VLD1d64T:
1682     case ARM::VLD1d8T_UPD:
1683     case ARM::VLD1d16T_UPD:
1684     case ARM::VLD1d32T_UPD:
1685     case ARM::VLD1d64T_UPD:
1686     case ARM::VLD1d8Q:
1687     case ARM::VLD1d16Q:
1688     case ARM::VLD1d32Q:
1689     case ARM::VLD1d64Q:
1690     case ARM::VLD1d8Q_UPD:
1691     case ARM::VLD1d16Q_UPD:
1692     case ARM::VLD1d32Q_UPD:
1693     case ARM::VLD1d64Q_UPD:
1694     case ARM::VLD2d8:
1695     case ARM::VLD2d16:
1696     case ARM::VLD2d32:
1697     case ARM::VLD2d8_UPD:
1698     case ARM::VLD2d16_UPD:
1699     case ARM::VLD2d32_UPD:
1700     case ARM::VLD2q8:
1701     case ARM::VLD2q16:
1702     case ARM::VLD2q32:
1703     case ARM::VLD2q8_UPD:
1704     case ARM::VLD2q16_UPD:
1705     case ARM::VLD2q32_UPD:
1706     case ARM::VLD3d8:
1707     case ARM::VLD3d16:
1708     case ARM::VLD3d32:
1709     case ARM::VLD3d8_UPD:
1710     case ARM::VLD3d16_UPD:
1711     case ARM::VLD3d32_UPD:
1712     case ARM::VLD4d8:
1713     case ARM::VLD4d16:
1714     case ARM::VLD4d32:
1715     case ARM::VLD4d8_UPD:
1716     case ARM::VLD4d16_UPD:
1717     case ARM::VLD4d32_UPD:
1718       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
1719         return MCDisassembler::Fail;
1720       break;
1721     case ARM::VLD2b8:
1722     case ARM::VLD2b16:
1723     case ARM::VLD2b32:
1724     case ARM::VLD2b8_UPD:
1725     case ARM::VLD2b16_UPD:
1726     case ARM::VLD2b32_UPD:
1727     case ARM::VLD3q8:
1728     case ARM::VLD3q16:
1729     case ARM::VLD3q32:
1730     case ARM::VLD3q8_UPD:
1731     case ARM::VLD3q16_UPD:
1732     case ARM::VLD3q32_UPD:
1733     case ARM::VLD4q8:
1734     case ARM::VLD4q16:
1735     case ARM::VLD4q32:
1736     case ARM::VLD4q8_UPD:
1737     case ARM::VLD4q16_UPD:
1738     case ARM::VLD4q32_UPD:
1739       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
1740         return MCDisassembler::Fail;
1741     default:
1742       break;
1743   }
1744 
1745   // Third output register
1746   switch(Inst.getOpcode()) {
1747     case ARM::VLD1d8T:
1748     case ARM::VLD1d16T:
1749     case ARM::VLD1d32T:
1750     case ARM::VLD1d64T:
1751     case ARM::VLD1d8T_UPD:
1752     case ARM::VLD1d16T_UPD:
1753     case ARM::VLD1d32T_UPD:
1754     case ARM::VLD1d64T_UPD:
1755     case ARM::VLD1d8Q:
1756     case ARM::VLD1d16Q:
1757     case ARM::VLD1d32Q:
1758     case ARM::VLD1d64Q:
1759     case ARM::VLD1d8Q_UPD:
1760     case ARM::VLD1d16Q_UPD:
1761     case ARM::VLD1d32Q_UPD:
1762     case ARM::VLD1d64Q_UPD:
1763     case ARM::VLD2q8:
1764     case ARM::VLD2q16:
1765     case ARM::VLD2q32:
1766     case ARM::VLD2q8_UPD:
1767     case ARM::VLD2q16_UPD:
1768     case ARM::VLD2q32_UPD:
1769     case ARM::VLD3d8:
1770     case ARM::VLD3d16:
1771     case ARM::VLD3d32:
1772     case ARM::VLD3d8_UPD:
1773     case ARM::VLD3d16_UPD:
1774     case ARM::VLD3d32_UPD:
1775     case ARM::VLD4d8:
1776     case ARM::VLD4d16:
1777     case ARM::VLD4d32:
1778     case ARM::VLD4d8_UPD:
1779     case ARM::VLD4d16_UPD:
1780     case ARM::VLD4d32_UPD:
1781       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
1782         return MCDisassembler::Fail;
1783       break;
1784     case ARM::VLD3q8:
1785     case ARM::VLD3q16:
1786     case ARM::VLD3q32:
1787     case ARM::VLD3q8_UPD:
1788     case ARM::VLD3q16_UPD:
1789     case ARM::VLD3q32_UPD:
1790     case ARM::VLD4q8:
1791     case ARM::VLD4q16:
1792     case ARM::VLD4q32:
1793     case ARM::VLD4q8_UPD:
1794     case ARM::VLD4q16_UPD:
1795     case ARM::VLD4q32_UPD:
1796       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
1797         return MCDisassembler::Fail;
1798       break;
1799     default:
1800       break;
1801   }
1802 
1803   // Fourth output register
1804   switch (Inst.getOpcode()) {
1805     case ARM::VLD1d8Q:
1806     case ARM::VLD1d16Q:
1807     case ARM::VLD1d32Q:
1808     case ARM::VLD1d64Q:
1809     case ARM::VLD1d8Q_UPD:
1810     case ARM::VLD1d16Q_UPD:
1811     case ARM::VLD1d32Q_UPD:
1812     case ARM::VLD1d64Q_UPD:
1813     case ARM::VLD2q8:
1814     case ARM::VLD2q16:
1815     case ARM::VLD2q32:
1816     case ARM::VLD2q8_UPD:
1817     case ARM::VLD2q16_UPD:
1818     case ARM::VLD2q32_UPD:
1819     case ARM::VLD4d8:
1820     case ARM::VLD4d16:
1821     case ARM::VLD4d32:
1822     case ARM::VLD4d8_UPD:
1823     case ARM::VLD4d16_UPD:
1824     case ARM::VLD4d32_UPD:
1825       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
1826         return MCDisassembler::Fail;
1827       break;
1828     case ARM::VLD4q8:
1829     case ARM::VLD4q16:
1830     case ARM::VLD4q32:
1831     case ARM::VLD4q8_UPD:
1832     case ARM::VLD4q16_UPD:
1833     case ARM::VLD4q32_UPD:
1834       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
1835         return MCDisassembler::Fail;
1836       break;
1837     default:
1838       break;
1839   }
1840 
1841   // Writeback operand
1842   switch (Inst.getOpcode()) {
1843     case ARM::VLD1d8_UPD:
1844     case ARM::VLD1d16_UPD:
1845     case ARM::VLD1d32_UPD:
1846     case ARM::VLD1d64_UPD:
1847     case ARM::VLD1q8_UPD:
1848     case ARM::VLD1q16_UPD:
1849     case ARM::VLD1q32_UPD:
1850     case ARM::VLD1q64_UPD:
1851     case ARM::VLD1d8T_UPD:
1852     case ARM::VLD1d16T_UPD:
1853     case ARM::VLD1d32T_UPD:
1854     case ARM::VLD1d64T_UPD:
1855     case ARM::VLD1d8Q_UPD:
1856     case ARM::VLD1d16Q_UPD:
1857     case ARM::VLD1d32Q_UPD:
1858     case ARM::VLD1d64Q_UPD:
1859     case ARM::VLD2d8_UPD:
1860     case ARM::VLD2d16_UPD:
1861     case ARM::VLD2d32_UPD:
1862     case ARM::VLD2q8_UPD:
1863     case ARM::VLD2q16_UPD:
1864     case ARM::VLD2q32_UPD:
1865     case ARM::VLD2b8_UPD:
1866     case ARM::VLD2b16_UPD:
1867     case ARM::VLD2b32_UPD:
1868     case ARM::VLD3d8_UPD:
1869     case ARM::VLD3d16_UPD:
1870     case ARM::VLD3d32_UPD:
1871     case ARM::VLD3q8_UPD:
1872     case ARM::VLD3q16_UPD:
1873     case ARM::VLD3q32_UPD:
1874     case ARM::VLD4d8_UPD:
1875     case ARM::VLD4d16_UPD:
1876     case ARM::VLD4d32_UPD:
1877     case ARM::VLD4q8_UPD:
1878     case ARM::VLD4q16_UPD:
1879     case ARM::VLD4q32_UPD:
1880       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
1881         return MCDisassembler::Fail;
1882       break;
1883     default:
1884       break;
1885   }
1886 
1887   // AddrMode6 Base (register+alignment)
1888   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
1889     return MCDisassembler::Fail;
1890 
1891   // AddrMode6 Offset (register)
1892   if (Rm == 0xD)
1893     Inst.addOperand(MCOperand::CreateReg(0));
1894   else if (Rm != 0xF) {
1895     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1896       return MCDisassembler::Fail;
1897   }
1898 
1899   return S;
1900 }
1901 
1902 static DecodeStatus DecodeVSTInstruction(llvm::MCInst &Inst, unsigned Insn,
1903                                  uint64_t Address, const void *Decoder) {
1904   DecodeStatus S = MCDisassembler::Success;
1905 
1906   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
1907   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
1908   unsigned wb = fieldFromInstruction32(Insn, 16, 4);
1909   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1910   Rn |= fieldFromInstruction32(Insn, 4, 2) << 4;
1911   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1912 
1913   // Writeback Operand
1914   switch (Inst.getOpcode()) {
1915     case ARM::VST1d8_UPD:
1916     case ARM::VST1d16_UPD:
1917     case ARM::VST1d32_UPD:
1918     case ARM::VST1d64_UPD:
1919     case ARM::VST1q8_UPD:
1920     case ARM::VST1q16_UPD:
1921     case ARM::VST1q32_UPD:
1922     case ARM::VST1q64_UPD:
1923     case ARM::VST1d8T_UPD:
1924     case ARM::VST1d16T_UPD:
1925     case ARM::VST1d32T_UPD:
1926     case ARM::VST1d64T_UPD:
1927     case ARM::VST1d8Q_UPD:
1928     case ARM::VST1d16Q_UPD:
1929     case ARM::VST1d32Q_UPD:
1930     case ARM::VST1d64Q_UPD:
1931     case ARM::VST2d8_UPD:
1932     case ARM::VST2d16_UPD:
1933     case ARM::VST2d32_UPD:
1934     case ARM::VST2q8_UPD:
1935     case ARM::VST2q16_UPD:
1936     case ARM::VST2q32_UPD:
1937     case ARM::VST2b8_UPD:
1938     case ARM::VST2b16_UPD:
1939     case ARM::VST2b32_UPD:
1940     case ARM::VST3d8_UPD:
1941     case ARM::VST3d16_UPD:
1942     case ARM::VST3d32_UPD:
1943     case ARM::VST3q8_UPD:
1944     case ARM::VST3q16_UPD:
1945     case ARM::VST3q32_UPD:
1946     case ARM::VST4d8_UPD:
1947     case ARM::VST4d16_UPD:
1948     case ARM::VST4d32_UPD:
1949     case ARM::VST4q8_UPD:
1950     case ARM::VST4q16_UPD:
1951     case ARM::VST4q32_UPD:
1952       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
1953         return MCDisassembler::Fail;
1954       break;
1955     default:
1956       break;
1957   }
1958 
1959   // AddrMode6 Base (register+alignment)
1960   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
1961     return MCDisassembler::Fail;
1962 
1963   // AddrMode6 Offset (register)
1964   if (Rm == 0xD)
1965     Inst.addOperand(MCOperand::CreateReg(0));
1966   else if (Rm != 0xF) {
1967     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1968     return MCDisassembler::Fail;
1969   }
1970 
1971   // First input register
1972   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
1973     return MCDisassembler::Fail;
1974 
1975   // Second input register
1976   switch (Inst.getOpcode()) {
1977     case ARM::VST1q8:
1978     case ARM::VST1q16:
1979     case ARM::VST1q32:
1980     case ARM::VST1q64:
1981     case ARM::VST1q8_UPD:
1982     case ARM::VST1q16_UPD:
1983     case ARM::VST1q32_UPD:
1984     case ARM::VST1q64_UPD:
1985     case ARM::VST1d8T:
1986     case ARM::VST1d16T:
1987     case ARM::VST1d32T:
1988     case ARM::VST1d64T:
1989     case ARM::VST1d8T_UPD:
1990     case ARM::VST1d16T_UPD:
1991     case ARM::VST1d32T_UPD:
1992     case ARM::VST1d64T_UPD:
1993     case ARM::VST1d8Q:
1994     case ARM::VST1d16Q:
1995     case ARM::VST1d32Q:
1996     case ARM::VST1d64Q:
1997     case ARM::VST1d8Q_UPD:
1998     case ARM::VST1d16Q_UPD:
1999     case ARM::VST1d32Q_UPD:
2000     case ARM::VST1d64Q_UPD:
2001     case ARM::VST2d8:
2002     case ARM::VST2d16:
2003     case ARM::VST2d32:
2004     case ARM::VST2d8_UPD:
2005     case ARM::VST2d16_UPD:
2006     case ARM::VST2d32_UPD:
2007     case ARM::VST2q8:
2008     case ARM::VST2q16:
2009     case ARM::VST2q32:
2010     case ARM::VST2q8_UPD:
2011     case ARM::VST2q16_UPD:
2012     case ARM::VST2q32_UPD:
2013     case ARM::VST3d8:
2014     case ARM::VST3d16:
2015     case ARM::VST3d32:
2016     case ARM::VST3d8_UPD:
2017     case ARM::VST3d16_UPD:
2018     case ARM::VST3d32_UPD:
2019     case ARM::VST4d8:
2020     case ARM::VST4d16:
2021     case ARM::VST4d32:
2022     case ARM::VST4d8_UPD:
2023     case ARM::VST4d16_UPD:
2024     case ARM::VST4d32_UPD:
2025       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
2026         return MCDisassembler::Fail;
2027       break;
2028     case ARM::VST2b8:
2029     case ARM::VST2b16:
2030     case ARM::VST2b32:
2031     case ARM::VST2b8_UPD:
2032     case ARM::VST2b16_UPD:
2033     case ARM::VST2b32_UPD:
2034     case ARM::VST3q8:
2035     case ARM::VST3q16:
2036     case ARM::VST3q32:
2037     case ARM::VST3q8_UPD:
2038     case ARM::VST3q16_UPD:
2039     case ARM::VST3q32_UPD:
2040     case ARM::VST4q8:
2041     case ARM::VST4q16:
2042     case ARM::VST4q32:
2043     case ARM::VST4q8_UPD:
2044     case ARM::VST4q16_UPD:
2045     case ARM::VST4q32_UPD:
2046       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2047         return MCDisassembler::Fail;
2048       break;
2049     default:
2050       break;
2051   }
2052 
2053   // Third input register
2054   switch (Inst.getOpcode()) {
2055     case ARM::VST1d8T:
2056     case ARM::VST1d16T:
2057     case ARM::VST1d32T:
2058     case ARM::VST1d64T:
2059     case ARM::VST1d8T_UPD:
2060     case ARM::VST1d16T_UPD:
2061     case ARM::VST1d32T_UPD:
2062     case ARM::VST1d64T_UPD:
2063     case ARM::VST1d8Q:
2064     case ARM::VST1d16Q:
2065     case ARM::VST1d32Q:
2066     case ARM::VST1d64Q:
2067     case ARM::VST1d8Q_UPD:
2068     case ARM::VST1d16Q_UPD:
2069     case ARM::VST1d32Q_UPD:
2070     case ARM::VST1d64Q_UPD:
2071     case ARM::VST2q8:
2072     case ARM::VST2q16:
2073     case ARM::VST2q32:
2074     case ARM::VST2q8_UPD:
2075     case ARM::VST2q16_UPD:
2076     case ARM::VST2q32_UPD:
2077     case ARM::VST3d8:
2078     case ARM::VST3d16:
2079     case ARM::VST3d32:
2080     case ARM::VST3d8_UPD:
2081     case ARM::VST3d16_UPD:
2082     case ARM::VST3d32_UPD:
2083     case ARM::VST4d8:
2084     case ARM::VST4d16:
2085     case ARM::VST4d32:
2086     case ARM::VST4d8_UPD:
2087     case ARM::VST4d16_UPD:
2088     case ARM::VST4d32_UPD:
2089       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2090         return MCDisassembler::Fail;
2091       break;
2092     case ARM::VST3q8:
2093     case ARM::VST3q16:
2094     case ARM::VST3q32:
2095     case ARM::VST3q8_UPD:
2096     case ARM::VST3q16_UPD:
2097     case ARM::VST3q32_UPD:
2098     case ARM::VST4q8:
2099     case ARM::VST4q16:
2100     case ARM::VST4q32:
2101     case ARM::VST4q8_UPD:
2102     case ARM::VST4q16_UPD:
2103     case ARM::VST4q32_UPD:
2104       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
2105         return MCDisassembler::Fail;
2106       break;
2107     default:
2108       break;
2109   }
2110 
2111   // Fourth input register
2112   switch (Inst.getOpcode()) {
2113     case ARM::VST1d8Q:
2114     case ARM::VST1d16Q:
2115     case ARM::VST1d32Q:
2116     case ARM::VST1d64Q:
2117     case ARM::VST1d8Q_UPD:
2118     case ARM::VST1d16Q_UPD:
2119     case ARM::VST1d32Q_UPD:
2120     case ARM::VST1d64Q_UPD:
2121     case ARM::VST2q8:
2122     case ARM::VST2q16:
2123     case ARM::VST2q32:
2124     case ARM::VST2q8_UPD:
2125     case ARM::VST2q16_UPD:
2126     case ARM::VST2q32_UPD:
2127     case ARM::VST4d8:
2128     case ARM::VST4d16:
2129     case ARM::VST4d32:
2130     case ARM::VST4d8_UPD:
2131     case ARM::VST4d16_UPD:
2132     case ARM::VST4d32_UPD:
2133       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
2134         return MCDisassembler::Fail;
2135       break;
2136     case ARM::VST4q8:
2137     case ARM::VST4q16:
2138     case ARM::VST4q32:
2139     case ARM::VST4q8_UPD:
2140     case ARM::VST4q16_UPD:
2141     case ARM::VST4q32_UPD:
2142       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
2143         return MCDisassembler::Fail;
2144       break;
2145     default:
2146       break;
2147   }
2148 
2149   return S;
2150 }
2151 
2152 static DecodeStatus DecodeVLD1DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2153                                     uint64_t Address, const void *Decoder) {
2154   DecodeStatus S = MCDisassembler::Success;
2155 
2156   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2157   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2158   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2159   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2160   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2161   unsigned size = fieldFromInstruction32(Insn, 6, 2);
2162   unsigned regs = fieldFromInstruction32(Insn, 5, 1) + 1;
2163 
2164   align *= (1 << size);
2165 
2166   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2167     return MCDisassembler::Fail;
2168   if (regs == 2) {
2169     if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
2170       return MCDisassembler::Fail;
2171   }
2172   if (Rm != 0xF) {
2173     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2174       return MCDisassembler::Fail;
2175   }
2176 
2177   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2178     return MCDisassembler::Fail;
2179   Inst.addOperand(MCOperand::CreateImm(align));
2180 
2181   if (Rm == 0xD)
2182     Inst.addOperand(MCOperand::CreateReg(0));
2183   else if (Rm != 0xF) {
2184     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2185       return MCDisassembler::Fail;
2186   }
2187 
2188   return S;
2189 }
2190 
2191 static DecodeStatus DecodeVLD2DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2192                                     uint64_t Address, const void *Decoder) {
2193   DecodeStatus S = MCDisassembler::Success;
2194 
2195   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2196   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2197   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2198   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2199   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2200   unsigned size = 1 << fieldFromInstruction32(Insn, 6, 2);
2201   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2202   align *= 2*size;
2203 
2204   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2205     return MCDisassembler::Fail;
2206   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
2207     return MCDisassembler::Fail;
2208   if (Rm != 0xF) {
2209     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2210       return MCDisassembler::Fail;
2211   }
2212 
2213   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2214     return MCDisassembler::Fail;
2215   Inst.addOperand(MCOperand::CreateImm(align));
2216 
2217   if (Rm == 0xD)
2218     Inst.addOperand(MCOperand::CreateReg(0));
2219   else if (Rm != 0xF) {
2220     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2221       return MCDisassembler::Fail;
2222   }
2223 
2224   return S;
2225 }
2226 
2227 static DecodeStatus DecodeVLD3DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2228                                     uint64_t Address, const void *Decoder) {
2229   DecodeStatus S = MCDisassembler::Success;
2230 
2231   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2232   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2233   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2234   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2235   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2236 
2237   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2238     return MCDisassembler::Fail;
2239   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
2240     return MCDisassembler::Fail;
2241   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
2242     return MCDisassembler::Fail;
2243   if (Rm != 0xF) {
2244     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2245       return MCDisassembler::Fail;
2246   }
2247 
2248   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2249     return MCDisassembler::Fail;
2250   Inst.addOperand(MCOperand::CreateImm(0));
2251 
2252   if (Rm == 0xD)
2253     Inst.addOperand(MCOperand::CreateReg(0));
2254   else if (Rm != 0xF) {
2255     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2256       return MCDisassembler::Fail;
2257   }
2258 
2259   return S;
2260 }
2261 
2262 static DecodeStatus DecodeVLD4DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2263                                     uint64_t Address, const void *Decoder) {
2264   DecodeStatus S = MCDisassembler::Success;
2265 
2266   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2267   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2268   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2269   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2270   unsigned size = fieldFromInstruction32(Insn, 6, 2);
2271   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2272   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2273 
2274   if (size == 0x3) {
2275     size = 4;
2276     align = 16;
2277   } else {
2278     if (size == 2) {
2279       size = 1 << size;
2280       align *= 8;
2281     } else {
2282       size = 1 << size;
2283       align *= 4*size;
2284     }
2285   }
2286 
2287   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2288     return MCDisassembler::Fail;
2289   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
2290     return MCDisassembler::Fail;
2291   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
2292     return MCDisassembler::Fail;
2293   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3*inc)%32, Address, Decoder)))
2294     return MCDisassembler::Fail;
2295   if (Rm != 0xF) {
2296     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2297       return MCDisassembler::Fail;
2298   }
2299 
2300   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2301     return MCDisassembler::Fail;
2302   Inst.addOperand(MCOperand::CreateImm(align));
2303 
2304   if (Rm == 0xD)
2305     Inst.addOperand(MCOperand::CreateReg(0));
2306   else if (Rm != 0xF) {
2307     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2308       return MCDisassembler::Fail;
2309   }
2310 
2311   return S;
2312 }
2313 
2314 static DecodeStatus
2315 DecodeNEONModImmInstruction(llvm::MCInst &Inst, unsigned Insn,
2316                             uint64_t Address, const void *Decoder) {
2317   DecodeStatus S = MCDisassembler::Success;
2318 
2319   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2320   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2321   unsigned imm = fieldFromInstruction32(Insn, 0, 4);
2322   imm |= fieldFromInstruction32(Insn, 16, 3) << 4;
2323   imm |= fieldFromInstruction32(Insn, 24, 1) << 7;
2324   imm |= fieldFromInstruction32(Insn, 8, 4) << 8;
2325   imm |= fieldFromInstruction32(Insn, 5, 1) << 12;
2326   unsigned Q = fieldFromInstruction32(Insn, 6, 1);
2327 
2328   if (Q) {
2329     if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2330     return MCDisassembler::Fail;
2331   } else {
2332     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2333     return MCDisassembler::Fail;
2334   }
2335 
2336   Inst.addOperand(MCOperand::CreateImm(imm));
2337 
2338   switch (Inst.getOpcode()) {
2339     case ARM::VORRiv4i16:
2340     case ARM::VORRiv2i32:
2341     case ARM::VBICiv4i16:
2342     case ARM::VBICiv2i32:
2343       if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2344         return MCDisassembler::Fail;
2345       break;
2346     case ARM::VORRiv8i16:
2347     case ARM::VORRiv4i32:
2348     case ARM::VBICiv8i16:
2349     case ARM::VBICiv4i32:
2350       if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2351         return MCDisassembler::Fail;
2352       break;
2353     default:
2354       break;
2355   }
2356 
2357   return S;
2358 }
2359 
2360 static DecodeStatus DecodeVSHLMaxInstruction(llvm::MCInst &Inst, unsigned Insn,
2361                                         uint64_t Address, const void *Decoder) {
2362   DecodeStatus S = MCDisassembler::Success;
2363 
2364   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2365   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2366   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2367   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
2368   unsigned size = fieldFromInstruction32(Insn, 18, 2);
2369 
2370   if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2371     return MCDisassembler::Fail;
2372   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
2373     return MCDisassembler::Fail;
2374   Inst.addOperand(MCOperand::CreateImm(8 << size));
2375 
2376   return S;
2377 }
2378 
2379 static DecodeStatus DecodeShiftRight8Imm(llvm::MCInst &Inst, unsigned Val,
2380                                uint64_t Address, const void *Decoder) {
2381   Inst.addOperand(MCOperand::CreateImm(8 - Val));
2382   return MCDisassembler::Success;
2383 }
2384 
2385 static DecodeStatus DecodeShiftRight16Imm(llvm::MCInst &Inst, unsigned Val,
2386                                uint64_t Address, const void *Decoder) {
2387   Inst.addOperand(MCOperand::CreateImm(16 - Val));
2388   return MCDisassembler::Success;
2389 }
2390 
2391 static DecodeStatus DecodeShiftRight32Imm(llvm::MCInst &Inst, unsigned Val,
2392                                uint64_t Address, const void *Decoder) {
2393   Inst.addOperand(MCOperand::CreateImm(32 - Val));
2394   return MCDisassembler::Success;
2395 }
2396 
2397 static DecodeStatus DecodeShiftRight64Imm(llvm::MCInst &Inst, unsigned Val,
2398                                uint64_t Address, const void *Decoder) {
2399   Inst.addOperand(MCOperand::CreateImm(64 - Val));
2400   return MCDisassembler::Success;
2401 }
2402 
2403 static DecodeStatus DecodeTBLInstruction(llvm::MCInst &Inst, unsigned Insn,
2404                                uint64_t Address, const void *Decoder) {
2405   DecodeStatus S = MCDisassembler::Success;
2406 
2407   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2408   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2409   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2410   Rn |= fieldFromInstruction32(Insn, 7, 1) << 4;
2411   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2412   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
2413   unsigned op = fieldFromInstruction32(Insn, 6, 1);
2414   unsigned length = fieldFromInstruction32(Insn, 8, 2) + 1;
2415 
2416   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2417     return MCDisassembler::Fail;
2418   if (op) {
2419     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2420     return MCDisassembler::Fail; // Writeback
2421   }
2422 
2423   for (unsigned i = 0; i < length; ++i) {
2424     if (!Check(S, DecodeDPRRegisterClass(Inst, (Rn+i)%32, Address, Decoder)))
2425     return MCDisassembler::Fail;
2426   }
2427 
2428   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
2429     return MCDisassembler::Fail;
2430 
2431   return S;
2432 }
2433 
2434 static DecodeStatus DecodeVFPfpImm(llvm::MCInst &Inst, unsigned Val,
2435                             uint64_t Address, const void *Decoder) {
2436   // The immediate needs to be a fully instantiated float.  However, the
2437   // auto-generated decoder is only able to fill in some of the bits
2438   // necessary.  For instance, the 'b' bit is replicated multiple times,
2439   // and is even present in inverted form in one bit.  We do a little
2440   // binary parsing here to fill in those missing bits, and then
2441   // reinterpret it all as a float.
2442   union {
2443     uint32_t integer;
2444     float fp;
2445   } fp_conv;
2446 
2447   fp_conv.integer = Val;
2448   uint32_t b = fieldFromInstruction32(Val, 25, 1);
2449   fp_conv.integer |= b << 26;
2450   fp_conv.integer |= b << 27;
2451   fp_conv.integer |= b << 28;
2452   fp_conv.integer |= b << 29;
2453   fp_conv.integer |= (~b & 0x1) << 30;
2454 
2455   Inst.addOperand(MCOperand::CreateFPImm(fp_conv.fp));
2456   return MCDisassembler::Success;
2457 }
2458 
2459 static DecodeStatus DecodeThumbAddSpecialReg(llvm::MCInst &Inst, uint16_t Insn,
2460                                      uint64_t Address, const void *Decoder) {
2461   DecodeStatus S = MCDisassembler::Success;
2462 
2463   unsigned dst = fieldFromInstruction16(Insn, 8, 3);
2464   unsigned imm = fieldFromInstruction16(Insn, 0, 8);
2465 
2466   if (!Check(S, DecodetGPRRegisterClass(Inst, dst, Address, Decoder)))
2467     return MCDisassembler::Fail;
2468 
2469   switch(Inst.getOpcode()) {
2470     default:
2471       return MCDisassembler::Fail;
2472     case ARM::tADR:
2473       break; // tADR does not explicitly represent the PC as an operand.
2474     case ARM::tADDrSPi:
2475       Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2476       break;
2477   }
2478 
2479   Inst.addOperand(MCOperand::CreateImm(imm));
2480   return S;
2481 }
2482 
2483 static DecodeStatus DecodeThumbBROperand(llvm::MCInst &Inst, unsigned Val,
2484                                  uint64_t Address, const void *Decoder) {
2485   Inst.addOperand(MCOperand::CreateImm(SignExtend32<12>(Val << 1)));
2486   return MCDisassembler::Success;
2487 }
2488 
2489 static DecodeStatus DecodeT2BROperand(llvm::MCInst &Inst, unsigned Val,
2490                                  uint64_t Address, const void *Decoder) {
2491   Inst.addOperand(MCOperand::CreateImm(SignExtend32<21>(Val)));
2492   return MCDisassembler::Success;
2493 }
2494 
2495 static DecodeStatus DecodeThumbCmpBROperand(llvm::MCInst &Inst, unsigned Val,
2496                                  uint64_t Address, const void *Decoder) {
2497   Inst.addOperand(MCOperand::CreateImm(SignExtend32<7>(Val << 1)));
2498   return MCDisassembler::Success;
2499 }
2500 
2501 static DecodeStatus DecodeThumbAddrModeRR(llvm::MCInst &Inst, unsigned Val,
2502                                  uint64_t Address, const void *Decoder) {
2503   DecodeStatus S = MCDisassembler::Success;
2504 
2505   unsigned Rn = fieldFromInstruction32(Val, 0, 3);
2506   unsigned Rm = fieldFromInstruction32(Val, 3, 3);
2507 
2508   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
2509     return MCDisassembler::Fail;
2510   if (!Check(S, DecodetGPRRegisterClass(Inst, Rm, Address, Decoder)))
2511     return MCDisassembler::Fail;
2512 
2513   return S;
2514 }
2515 
2516 static DecodeStatus DecodeThumbAddrModeIS(llvm::MCInst &Inst, unsigned Val,
2517                                   uint64_t Address, const void *Decoder) {
2518   DecodeStatus S = MCDisassembler::Success;
2519 
2520   unsigned Rn = fieldFromInstruction32(Val, 0, 3);
2521   unsigned imm = fieldFromInstruction32(Val, 3, 5);
2522 
2523   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
2524     return MCDisassembler::Fail;
2525   Inst.addOperand(MCOperand::CreateImm(imm));
2526 
2527   return S;
2528 }
2529 
2530 static DecodeStatus DecodeThumbAddrModePC(llvm::MCInst &Inst, unsigned Val,
2531                                   uint64_t Address, const void *Decoder) {
2532   Inst.addOperand(MCOperand::CreateImm(Val << 2));
2533 
2534   return MCDisassembler::Success;
2535 }
2536 
2537 static DecodeStatus DecodeThumbAddrModeSP(llvm::MCInst &Inst, unsigned Val,
2538                                   uint64_t Address, const void *Decoder) {
2539   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2540   Inst.addOperand(MCOperand::CreateImm(Val));
2541 
2542   return MCDisassembler::Success;
2543 }
2544 
2545 static DecodeStatus DecodeT2AddrModeSOReg(llvm::MCInst &Inst, unsigned Val,
2546                                   uint64_t Address, const void *Decoder) {
2547   DecodeStatus S = MCDisassembler::Success;
2548 
2549   unsigned Rn = fieldFromInstruction32(Val, 6, 4);
2550   unsigned Rm = fieldFromInstruction32(Val, 2, 4);
2551   unsigned imm = fieldFromInstruction32(Val, 0, 2);
2552 
2553   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2554     return MCDisassembler::Fail;
2555   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
2556     return MCDisassembler::Fail;
2557   Inst.addOperand(MCOperand::CreateImm(imm));
2558 
2559   return S;
2560 }
2561 
2562 static DecodeStatus DecodeT2LoadShift(llvm::MCInst &Inst, unsigned Insn,
2563                               uint64_t Address, const void *Decoder) {
2564   DecodeStatus S = MCDisassembler::Success;
2565 
2566   switch (Inst.getOpcode()) {
2567     case ARM::t2PLDs:
2568     case ARM::t2PLDWs:
2569     case ARM::t2PLIs:
2570       break;
2571     default: {
2572       unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2573       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
2574     return MCDisassembler::Fail;
2575     }
2576   }
2577 
2578   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2579   if (Rn == 0xF) {
2580     switch (Inst.getOpcode()) {
2581       case ARM::t2LDRBs:
2582         Inst.setOpcode(ARM::t2LDRBpci);
2583         break;
2584       case ARM::t2LDRHs:
2585         Inst.setOpcode(ARM::t2LDRHpci);
2586         break;
2587       case ARM::t2LDRSHs:
2588         Inst.setOpcode(ARM::t2LDRSHpci);
2589         break;
2590       case ARM::t2LDRSBs:
2591         Inst.setOpcode(ARM::t2LDRSBpci);
2592         break;
2593       case ARM::t2PLDs:
2594         Inst.setOpcode(ARM::t2PLDi12);
2595         Inst.addOperand(MCOperand::CreateReg(ARM::PC));
2596         break;
2597       default:
2598         return MCDisassembler::Fail;
2599     }
2600 
2601     int imm = fieldFromInstruction32(Insn, 0, 12);
2602     if (!fieldFromInstruction32(Insn, 23, 1)) imm *= -1;
2603     Inst.addOperand(MCOperand::CreateImm(imm));
2604 
2605     return S;
2606   }
2607 
2608   unsigned addrmode = fieldFromInstruction32(Insn, 4, 2);
2609   addrmode |= fieldFromInstruction32(Insn, 0, 4) << 2;
2610   addrmode |= fieldFromInstruction32(Insn, 16, 4) << 6;
2611   if (!Check(S, DecodeT2AddrModeSOReg(Inst, addrmode, Address, Decoder)))
2612     return MCDisassembler::Fail;
2613 
2614   return S;
2615 }
2616 
2617 static DecodeStatus DecodeT2Imm8S4(llvm::MCInst &Inst, unsigned Val,
2618                            uint64_t Address, const void *Decoder) {
2619   int imm = Val & 0xFF;
2620   if (!(Val & 0x100)) imm *= -1;
2621   Inst.addOperand(MCOperand::CreateImm(imm << 2));
2622 
2623   return MCDisassembler::Success;
2624 }
2625 
2626 static DecodeStatus DecodeT2AddrModeImm8s4(llvm::MCInst &Inst, unsigned Val,
2627                                    uint64_t Address, const void *Decoder) {
2628   DecodeStatus S = MCDisassembler::Success;
2629 
2630   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
2631   unsigned imm = fieldFromInstruction32(Val, 0, 9);
2632 
2633   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2634     return MCDisassembler::Fail;
2635   if (!Check(S, DecodeT2Imm8S4(Inst, imm, Address, Decoder)))
2636     return MCDisassembler::Fail;
2637 
2638   return S;
2639 }
2640 
2641 static DecodeStatus DecodeT2Imm8(llvm::MCInst &Inst, unsigned Val,
2642                          uint64_t Address, const void *Decoder) {
2643   int imm = Val & 0xFF;
2644   if (!(Val & 0x100)) imm *= -1;
2645   Inst.addOperand(MCOperand::CreateImm(imm));
2646 
2647   return MCDisassembler::Success;
2648 }
2649 
2650 
2651 static DecodeStatus DecodeT2AddrModeImm8(llvm::MCInst &Inst, unsigned Val,
2652                                  uint64_t Address, const void *Decoder) {
2653   DecodeStatus S = MCDisassembler::Success;
2654 
2655   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
2656   unsigned imm = fieldFromInstruction32(Val, 0, 9);
2657 
2658   // Some instructions always use an additive offset.
2659   switch (Inst.getOpcode()) {
2660     case ARM::t2LDRT:
2661     case ARM::t2LDRBT:
2662     case ARM::t2LDRHT:
2663     case ARM::t2LDRSBT:
2664     case ARM::t2LDRSHT:
2665       imm |= 0x100;
2666       break;
2667     default:
2668       break;
2669   }
2670 
2671   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2672     return MCDisassembler::Fail;
2673   if (!Check(S, DecodeT2Imm8(Inst, imm, Address, Decoder)))
2674     return MCDisassembler::Fail;
2675 
2676   return S;
2677 }
2678 
2679 
2680 static DecodeStatus DecodeT2AddrModeImm12(llvm::MCInst &Inst, unsigned Val,
2681                                   uint64_t Address, const void *Decoder) {
2682   DecodeStatus S = MCDisassembler::Success;
2683 
2684   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
2685   unsigned imm = fieldFromInstruction32(Val, 0, 12);
2686 
2687   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2688     return MCDisassembler::Fail;
2689   Inst.addOperand(MCOperand::CreateImm(imm));
2690 
2691   return S;
2692 }
2693 
2694 
2695 static DecodeStatus DecodeThumbAddSPImm(llvm::MCInst &Inst, uint16_t Insn,
2696                                 uint64_t Address, const void *Decoder) {
2697   unsigned imm = fieldFromInstruction16(Insn, 0, 7);
2698 
2699   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2700   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2701   Inst.addOperand(MCOperand::CreateImm(imm));
2702 
2703   return MCDisassembler::Success;
2704 }
2705 
2706 static DecodeStatus DecodeThumbAddSPReg(llvm::MCInst &Inst, uint16_t Insn,
2707                                 uint64_t Address, const void *Decoder) {
2708   DecodeStatus S = MCDisassembler::Success;
2709 
2710   if (Inst.getOpcode() == ARM::tADDrSP) {
2711     unsigned Rdm = fieldFromInstruction16(Insn, 0, 3);
2712     Rdm |= fieldFromInstruction16(Insn, 7, 1) << 3;
2713 
2714     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
2715     return MCDisassembler::Fail;
2716     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
2717     return MCDisassembler::Fail;
2718     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2719   } else if (Inst.getOpcode() == ARM::tADDspr) {
2720     unsigned Rm = fieldFromInstruction16(Insn, 3, 4);
2721 
2722     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2723     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2724     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2725     return MCDisassembler::Fail;
2726   }
2727 
2728   return S;
2729 }
2730 
2731 static DecodeStatus DecodeThumbCPS(llvm::MCInst &Inst, uint16_t Insn,
2732                            uint64_t Address, const void *Decoder) {
2733   unsigned imod = fieldFromInstruction16(Insn, 4, 1) | 0x2;
2734   unsigned flags = fieldFromInstruction16(Insn, 0, 3);
2735 
2736   Inst.addOperand(MCOperand::CreateImm(imod));
2737   Inst.addOperand(MCOperand::CreateImm(flags));
2738 
2739   return MCDisassembler::Success;
2740 }
2741 
2742 static DecodeStatus DecodePostIdxReg(llvm::MCInst &Inst, unsigned Insn,
2743                              uint64_t Address, const void *Decoder) {
2744   DecodeStatus S = MCDisassembler::Success;
2745   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2746   unsigned add = fieldFromInstruction32(Insn, 4, 1);
2747 
2748   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2749     return MCDisassembler::Fail;
2750   Inst.addOperand(MCOperand::CreateImm(add));
2751 
2752   return S;
2753 }
2754 
2755 static DecodeStatus DecodeThumbBLXOffset(llvm::MCInst &Inst, unsigned Val,
2756                                  uint64_t Address, const void *Decoder) {
2757   Inst.addOperand(MCOperand::CreateImm(SignExtend32<22>(Val << 1)));
2758   return MCDisassembler::Success;
2759 }
2760 
2761 static DecodeStatus DecodeCoprocessor(llvm::MCInst &Inst, unsigned Val,
2762                               uint64_t Address, const void *Decoder) {
2763   if (Val == 0xA || Val == 0xB)
2764     return MCDisassembler::Fail;
2765 
2766   Inst.addOperand(MCOperand::CreateImm(Val));
2767   return MCDisassembler::Success;
2768 }
2769 
2770 static DecodeStatus
2771 DecodeThumb2BCCInstruction(llvm::MCInst &Inst, unsigned Insn,
2772                            uint64_t Address, const void *Decoder) {
2773   DecodeStatus S = MCDisassembler::Success;
2774 
2775   unsigned pred = fieldFromInstruction32(Insn, 22, 4);
2776   if (pred == 0xE || pred == 0xF) {
2777     unsigned opc = fieldFromInstruction32(Insn, 4, 28);
2778     switch (opc) {
2779       default:
2780         return MCDisassembler::Fail;
2781       case 0xf3bf8f4:
2782         Inst.setOpcode(ARM::t2DSB);
2783         break;
2784       case 0xf3bf8f5:
2785         Inst.setOpcode(ARM::t2DMB);
2786         break;
2787       case 0xf3bf8f6:
2788         Inst.setOpcode(ARM::t2ISB);
2789         return MCDisassembler::Success;
2790     }
2791 
2792     unsigned imm = fieldFromInstruction32(Insn, 0, 4);
2793     return DecodeMemBarrierOption(Inst, imm, Address, Decoder);
2794   }
2795 
2796   unsigned brtarget = fieldFromInstruction32(Insn, 0, 11) << 1;
2797   brtarget |= fieldFromInstruction32(Insn, 11, 1) << 19;
2798   brtarget |= fieldFromInstruction32(Insn, 13, 1) << 18;
2799   brtarget |= fieldFromInstruction32(Insn, 16, 6) << 12;
2800   brtarget |= fieldFromInstruction32(Insn, 26, 1) << 20;
2801 
2802   if (!Check(S, DecodeT2BROperand(Inst, brtarget, Address, Decoder)))
2803     return MCDisassembler::Fail;
2804   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2805     return MCDisassembler::Fail;
2806 
2807   return S;
2808 }
2809 
2810 // Decode a shifted immediate operand.  These basically consist
2811 // of an 8-bit value, and a 4-bit directive that specifies either
2812 // a splat operation or a rotation.
2813 static DecodeStatus DecodeT2SOImm(llvm::MCInst &Inst, unsigned Val,
2814                           uint64_t Address, const void *Decoder) {
2815   unsigned ctrl = fieldFromInstruction32(Val, 10, 2);
2816   if (ctrl == 0) {
2817     unsigned byte = fieldFromInstruction32(Val, 8, 2);
2818     unsigned imm = fieldFromInstruction32(Val, 0, 8);
2819     switch (byte) {
2820       case 0:
2821         Inst.addOperand(MCOperand::CreateImm(imm));
2822         break;
2823       case 1:
2824         Inst.addOperand(MCOperand::CreateImm((imm << 16) | imm));
2825         break;
2826       case 2:
2827         Inst.addOperand(MCOperand::CreateImm((imm << 24) | (imm << 8)));
2828         break;
2829       case 3:
2830         Inst.addOperand(MCOperand::CreateImm((imm << 24) | (imm << 16) |
2831                                              (imm << 8)  |  imm));
2832         break;
2833     }
2834   } else {
2835     unsigned unrot = fieldFromInstruction32(Val, 0, 7) | 0x80;
2836     unsigned rot = fieldFromInstruction32(Val, 7, 5);
2837     unsigned imm = (unrot >> rot) | (unrot << ((32-rot)&31));
2838     Inst.addOperand(MCOperand::CreateImm(imm));
2839   }
2840 
2841   return MCDisassembler::Success;
2842 }
2843 
2844 static DecodeStatus
2845 DecodeThumbBCCTargetOperand(llvm::MCInst &Inst, unsigned Val,
2846                             uint64_t Address, const void *Decoder){
2847   Inst.addOperand(MCOperand::CreateImm(Val << 1));
2848   return MCDisassembler::Success;
2849 }
2850 
2851 static DecodeStatus DecodeThumbBLTargetOperand(llvm::MCInst &Inst, unsigned Val,
2852                                        uint64_t Address, const void *Decoder){
2853   Inst.addOperand(MCOperand::CreateImm(SignExtend32<22>(Val << 1)));
2854   return MCDisassembler::Success;
2855 }
2856 
2857 static DecodeStatus DecodeMemBarrierOption(llvm::MCInst &Inst, unsigned Val,
2858                                    uint64_t Address, const void *Decoder) {
2859   switch (Val) {
2860   default:
2861     return MCDisassembler::Fail;
2862   case 0xF: // SY
2863   case 0xE: // ST
2864   case 0xB: // ISH
2865   case 0xA: // ISHST
2866   case 0x7: // NSH
2867   case 0x6: // NSHST
2868   case 0x3: // OSH
2869   case 0x2: // OSHST
2870     break;
2871   }
2872 
2873   Inst.addOperand(MCOperand::CreateImm(Val));
2874   return MCDisassembler::Success;
2875 }
2876 
2877 static DecodeStatus DecodeMSRMask(llvm::MCInst &Inst, unsigned Val,
2878                           uint64_t Address, const void *Decoder) {
2879   if (!Val) return MCDisassembler::Fail;
2880   Inst.addOperand(MCOperand::CreateImm(Val));
2881   return MCDisassembler::Success;
2882 }
2883 
2884 static DecodeStatus DecodeDoubleRegLoad(llvm::MCInst &Inst, unsigned Insn,
2885                                         uint64_t Address, const void *Decoder) {
2886   DecodeStatus S = MCDisassembler::Success;
2887 
2888   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2889   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2890   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
2891 
2892   if ((Rt & 1) || Rt == 0xE || Rn == 0xF) return MCDisassembler::Fail;
2893 
2894   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
2895     return MCDisassembler::Fail;
2896   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
2897     return MCDisassembler::Fail;
2898   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2899     return MCDisassembler::Fail;
2900   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2901     return MCDisassembler::Fail;
2902 
2903   return S;
2904 }
2905 
2906 
2907 static DecodeStatus DecodeDoubleRegStore(llvm::MCInst &Inst, unsigned Insn,
2908                                          uint64_t Address, const void *Decoder){
2909   DecodeStatus S = MCDisassembler::Success;
2910 
2911   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2912   unsigned Rt = fieldFromInstruction32(Insn, 0, 4);
2913   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2914   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
2915 
2916   if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
2917     return MCDisassembler::Fail;
2918 
2919   if ((Rt & 1) || Rt == 0xE || Rn == 0xF) return MCDisassembler::Fail;
2920   if (Rd == Rn || Rd == Rt || Rd == Rt+1) return MCDisassembler::Fail;
2921 
2922   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
2923     return MCDisassembler::Fail;
2924   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
2925     return MCDisassembler::Fail;
2926   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2927     return MCDisassembler::Fail;
2928   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2929     return MCDisassembler::Fail;
2930 
2931   return S;
2932 }
2933 
2934 static DecodeStatus DecodeLDRPreImm(llvm::MCInst &Inst, unsigned Insn,
2935                             uint64_t Address, const void *Decoder) {
2936   DecodeStatus S = MCDisassembler::Success;
2937 
2938   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2939   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2940   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
2941   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
2942   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
2943   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
2944 
2945   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
2946 
2947   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
2948     return MCDisassembler::Fail;
2949   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2950     return MCDisassembler::Fail;
2951   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
2952     return MCDisassembler::Fail;
2953   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2954     return MCDisassembler::Fail;
2955 
2956   return S;
2957 }
2958 
2959 static DecodeStatus DecodeLDRPreReg(llvm::MCInst &Inst, unsigned Insn,
2960                             uint64_t Address, const void *Decoder) {
2961   DecodeStatus S = MCDisassembler::Success;
2962 
2963   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2964   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2965   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
2966   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
2967   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
2968   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
2969   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2970 
2971   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
2972   if (Rm == 0xF) S = MCDisassembler::SoftFail;
2973 
2974   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
2975     return MCDisassembler::Fail;
2976   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2977     return MCDisassembler::Fail;
2978   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
2979     return MCDisassembler::Fail;
2980   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2981     return MCDisassembler::Fail;
2982 
2983   return S;
2984 }
2985 
2986 
2987 static DecodeStatus DecodeSTRPreImm(llvm::MCInst &Inst, unsigned Insn,
2988                             uint64_t Address, const void *Decoder) {
2989   DecodeStatus S = MCDisassembler::Success;
2990 
2991   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2992   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2993   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
2994   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
2995   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
2996   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
2997 
2998   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
2999 
3000   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3001     return MCDisassembler::Fail;
3002   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3003     return MCDisassembler::Fail;
3004   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
3005     return MCDisassembler::Fail;
3006   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3007     return MCDisassembler::Fail;
3008 
3009   return S;
3010 }
3011 
3012 static DecodeStatus DecodeSTRPreReg(llvm::MCInst &Inst, unsigned Insn,
3013                             uint64_t Address, const void *Decoder) {
3014   DecodeStatus S = MCDisassembler::Success;
3015 
3016   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3017   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3018   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3019   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3020   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3021   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3022 
3023   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3024 
3025   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3026     return MCDisassembler::Fail;
3027   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3028     return MCDisassembler::Fail;
3029   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
3030     return MCDisassembler::Fail;
3031   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3032     return MCDisassembler::Fail;
3033 
3034   return S;
3035 }
3036 
3037 static DecodeStatus DecodeVLD1LN(llvm::MCInst &Inst, unsigned Insn,
3038                          uint64_t Address, const void *Decoder) {
3039   DecodeStatus S = MCDisassembler::Success;
3040 
3041   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3042   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3043   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3044   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3045   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3046 
3047   unsigned align = 0;
3048   unsigned index = 0;
3049   switch (size) {
3050     default:
3051       return MCDisassembler::Fail;
3052     case 0:
3053       if (fieldFromInstruction32(Insn, 4, 1))
3054         return MCDisassembler::Fail; // UNDEFINED
3055       index = fieldFromInstruction32(Insn, 5, 3);
3056       break;
3057     case 1:
3058       if (fieldFromInstruction32(Insn, 5, 1))
3059         return MCDisassembler::Fail; // UNDEFINED
3060       index = fieldFromInstruction32(Insn, 6, 2);
3061       if (fieldFromInstruction32(Insn, 4, 1))
3062         align = 2;
3063       break;
3064     case 2:
3065       if (fieldFromInstruction32(Insn, 6, 1))
3066         return MCDisassembler::Fail; // UNDEFINED
3067       index = fieldFromInstruction32(Insn, 7, 1);
3068       if (fieldFromInstruction32(Insn, 4, 2) != 0)
3069         align = 4;
3070   }
3071 
3072   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3073     return MCDisassembler::Fail;
3074   if (Rm != 0xF) { // Writeback
3075     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3076       return MCDisassembler::Fail;
3077   }
3078   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3079     return MCDisassembler::Fail;
3080   Inst.addOperand(MCOperand::CreateImm(align));
3081   if (Rm != 0xF) {
3082     if (Rm != 0xD) {
3083       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3084         return MCDisassembler::Fail;
3085     } else
3086       Inst.addOperand(MCOperand::CreateReg(0));
3087   }
3088 
3089   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3090     return MCDisassembler::Fail;
3091   Inst.addOperand(MCOperand::CreateImm(index));
3092 
3093   return S;
3094 }
3095 
3096 static DecodeStatus DecodeVST1LN(llvm::MCInst &Inst, unsigned Insn,
3097                          uint64_t Address, const void *Decoder) {
3098   DecodeStatus S = MCDisassembler::Success;
3099 
3100   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3101   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3102   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3103   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3104   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3105 
3106   unsigned align = 0;
3107   unsigned index = 0;
3108   switch (size) {
3109     default:
3110       return MCDisassembler::Fail;
3111     case 0:
3112       if (fieldFromInstruction32(Insn, 4, 1))
3113         return MCDisassembler::Fail; // UNDEFINED
3114       index = fieldFromInstruction32(Insn, 5, 3);
3115       break;
3116     case 1:
3117       if (fieldFromInstruction32(Insn, 5, 1))
3118         return MCDisassembler::Fail; // UNDEFINED
3119       index = fieldFromInstruction32(Insn, 6, 2);
3120       if (fieldFromInstruction32(Insn, 4, 1))
3121         align = 2;
3122       break;
3123     case 2:
3124       if (fieldFromInstruction32(Insn, 6, 1))
3125         return MCDisassembler::Fail; // UNDEFINED
3126       index = fieldFromInstruction32(Insn, 7, 1);
3127       if (fieldFromInstruction32(Insn, 4, 2) != 0)
3128         align = 4;
3129   }
3130 
3131   if (Rm != 0xF) { // Writeback
3132     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3133     return MCDisassembler::Fail;
3134   }
3135   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3136     return MCDisassembler::Fail;
3137   Inst.addOperand(MCOperand::CreateImm(align));
3138   if (Rm != 0xF) {
3139     if (Rm != 0xD) {
3140       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3141     return MCDisassembler::Fail;
3142     } else
3143       Inst.addOperand(MCOperand::CreateReg(0));
3144   }
3145 
3146   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3147     return MCDisassembler::Fail;
3148   Inst.addOperand(MCOperand::CreateImm(index));
3149 
3150   return S;
3151 }
3152 
3153 
3154 static DecodeStatus DecodeVLD2LN(llvm::MCInst &Inst, unsigned Insn,
3155                          uint64_t Address, const void *Decoder) {
3156   DecodeStatus S = MCDisassembler::Success;
3157 
3158   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3159   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3160   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3161   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3162   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3163 
3164   unsigned align = 0;
3165   unsigned index = 0;
3166   unsigned inc = 1;
3167   switch (size) {
3168     default:
3169       return MCDisassembler::Fail;
3170     case 0:
3171       index = fieldFromInstruction32(Insn, 5, 3);
3172       if (fieldFromInstruction32(Insn, 4, 1))
3173         align = 2;
3174       break;
3175     case 1:
3176       index = fieldFromInstruction32(Insn, 6, 2);
3177       if (fieldFromInstruction32(Insn, 4, 1))
3178         align = 4;
3179       if (fieldFromInstruction32(Insn, 5, 1))
3180         inc = 2;
3181       break;
3182     case 2:
3183       if (fieldFromInstruction32(Insn, 5, 1))
3184         return MCDisassembler::Fail; // UNDEFINED
3185       index = fieldFromInstruction32(Insn, 7, 1);
3186       if (fieldFromInstruction32(Insn, 4, 1) != 0)
3187         align = 8;
3188       if (fieldFromInstruction32(Insn, 6, 1))
3189         inc = 2;
3190       break;
3191   }
3192 
3193   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3194     return MCDisassembler::Fail;
3195   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3196     return MCDisassembler::Fail;
3197   if (Rm != 0xF) { // Writeback
3198     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3199       return MCDisassembler::Fail;
3200   }
3201   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3202     return MCDisassembler::Fail;
3203   Inst.addOperand(MCOperand::CreateImm(align));
3204   if (Rm != 0xF) {
3205     if (Rm != 0xD) {
3206       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3207         return MCDisassembler::Fail;
3208     } else
3209       Inst.addOperand(MCOperand::CreateReg(0));
3210   }
3211 
3212   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3213     return MCDisassembler::Fail;
3214   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3215     return MCDisassembler::Fail;
3216   Inst.addOperand(MCOperand::CreateImm(index));
3217 
3218   return S;
3219 }
3220 
3221 static DecodeStatus DecodeVST2LN(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   unsigned inc = 1;
3234   switch (size) {
3235     default:
3236       return MCDisassembler::Fail;
3237     case 0:
3238       index = fieldFromInstruction32(Insn, 5, 3);
3239       if (fieldFromInstruction32(Insn, 4, 1))
3240         align = 2;
3241       break;
3242     case 1:
3243       index = fieldFromInstruction32(Insn, 6, 2);
3244       if (fieldFromInstruction32(Insn, 4, 1))
3245         align = 4;
3246       if (fieldFromInstruction32(Insn, 5, 1))
3247         inc = 2;
3248       break;
3249     case 2:
3250       if (fieldFromInstruction32(Insn, 5, 1))
3251         return MCDisassembler::Fail; // UNDEFINED
3252       index = fieldFromInstruction32(Insn, 7, 1);
3253       if (fieldFromInstruction32(Insn, 4, 1) != 0)
3254         align = 8;
3255       if (fieldFromInstruction32(Insn, 6, 1))
3256         inc = 2;
3257       break;
3258   }
3259 
3260   if (Rm != 0xF) { // Writeback
3261     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3262       return MCDisassembler::Fail;
3263   }
3264   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3265     return MCDisassembler::Fail;
3266   Inst.addOperand(MCOperand::CreateImm(align));
3267   if (Rm != 0xF) {
3268     if (Rm != 0xD) {
3269       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3270         return MCDisassembler::Fail;
3271     } else
3272       Inst.addOperand(MCOperand::CreateReg(0));
3273   }
3274 
3275   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3276     return MCDisassembler::Fail;
3277   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3278     return MCDisassembler::Fail;
3279   Inst.addOperand(MCOperand::CreateImm(index));
3280 
3281   return S;
3282 }
3283 
3284 
3285 static DecodeStatus DecodeVLD3LN(llvm::MCInst &Inst, unsigned Insn,
3286                          uint64_t Address, const void *Decoder) {
3287   DecodeStatus S = MCDisassembler::Success;
3288 
3289   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3290   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3291   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3292   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3293   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3294 
3295   unsigned align = 0;
3296   unsigned index = 0;
3297   unsigned inc = 1;
3298   switch (size) {
3299     default:
3300       return MCDisassembler::Fail;
3301     case 0:
3302       if (fieldFromInstruction32(Insn, 4, 1))
3303         return MCDisassembler::Fail; // UNDEFINED
3304       index = fieldFromInstruction32(Insn, 5, 3);
3305       break;
3306     case 1:
3307       if (fieldFromInstruction32(Insn, 4, 1))
3308         return MCDisassembler::Fail; // UNDEFINED
3309       index = fieldFromInstruction32(Insn, 6, 2);
3310       if (fieldFromInstruction32(Insn, 5, 1))
3311         inc = 2;
3312       break;
3313     case 2:
3314       if (fieldFromInstruction32(Insn, 4, 2))
3315         return MCDisassembler::Fail; // UNDEFINED
3316       index = fieldFromInstruction32(Insn, 7, 1);
3317       if (fieldFromInstruction32(Insn, 6, 1))
3318         inc = 2;
3319       break;
3320   }
3321 
3322   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3323     return MCDisassembler::Fail;
3324   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3325     return MCDisassembler::Fail;
3326   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3327     return MCDisassembler::Fail;
3328 
3329   if (Rm != 0xF) { // Writeback
3330     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3331     return MCDisassembler::Fail;
3332   }
3333   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3334     return MCDisassembler::Fail;
3335   Inst.addOperand(MCOperand::CreateImm(align));
3336   if (Rm != 0xF) {
3337     if (Rm != 0xD) {
3338       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3339     return MCDisassembler::Fail;
3340     } else
3341       Inst.addOperand(MCOperand::CreateReg(0));
3342   }
3343 
3344   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3345     return MCDisassembler::Fail;
3346   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3347     return MCDisassembler::Fail;
3348   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3349     return MCDisassembler::Fail;
3350   Inst.addOperand(MCOperand::CreateImm(index));
3351 
3352   return S;
3353 }
3354 
3355 static DecodeStatus DecodeVST3LN(llvm::MCInst &Inst, unsigned Insn,
3356                          uint64_t Address, const void *Decoder) {
3357   DecodeStatus S = MCDisassembler::Success;
3358 
3359   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3360   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3361   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3362   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3363   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3364 
3365   unsigned align = 0;
3366   unsigned index = 0;
3367   unsigned inc = 1;
3368   switch (size) {
3369     default:
3370       return MCDisassembler::Fail;
3371     case 0:
3372       if (fieldFromInstruction32(Insn, 4, 1))
3373         return MCDisassembler::Fail; // UNDEFINED
3374       index = fieldFromInstruction32(Insn, 5, 3);
3375       break;
3376     case 1:
3377       if (fieldFromInstruction32(Insn, 4, 1))
3378         return MCDisassembler::Fail; // UNDEFINED
3379       index = fieldFromInstruction32(Insn, 6, 2);
3380       if (fieldFromInstruction32(Insn, 5, 1))
3381         inc = 2;
3382       break;
3383     case 2:
3384       if (fieldFromInstruction32(Insn, 4, 2))
3385         return MCDisassembler::Fail; // UNDEFINED
3386       index = fieldFromInstruction32(Insn, 7, 1);
3387       if (fieldFromInstruction32(Insn, 6, 1))
3388         inc = 2;
3389       break;
3390   }
3391 
3392   if (Rm != 0xF) { // Writeback
3393     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3394     return MCDisassembler::Fail;
3395   }
3396   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3397     return MCDisassembler::Fail;
3398   Inst.addOperand(MCOperand::CreateImm(align));
3399   if (Rm != 0xF) {
3400     if (Rm != 0xD) {
3401       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3402     return MCDisassembler::Fail;
3403     } else
3404       Inst.addOperand(MCOperand::CreateReg(0));
3405   }
3406 
3407   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3408     return MCDisassembler::Fail;
3409   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3410     return MCDisassembler::Fail;
3411   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3412     return MCDisassembler::Fail;
3413   Inst.addOperand(MCOperand::CreateImm(index));
3414 
3415   return S;
3416 }
3417 
3418 
3419 static DecodeStatus DecodeVLD4LN(llvm::MCInst &Inst, unsigned Insn,
3420                          uint64_t Address, const void *Decoder) {
3421   DecodeStatus S = MCDisassembler::Success;
3422 
3423   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3424   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3425   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3426   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3427   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3428 
3429   unsigned align = 0;
3430   unsigned index = 0;
3431   unsigned inc = 1;
3432   switch (size) {
3433     default:
3434       return MCDisassembler::Fail;
3435     case 0:
3436       if (fieldFromInstruction32(Insn, 4, 1))
3437         align = 4;
3438       index = fieldFromInstruction32(Insn, 5, 3);
3439       break;
3440     case 1:
3441       if (fieldFromInstruction32(Insn, 4, 1))
3442         align = 8;
3443       index = fieldFromInstruction32(Insn, 6, 2);
3444       if (fieldFromInstruction32(Insn, 5, 1))
3445         inc = 2;
3446       break;
3447     case 2:
3448       if (fieldFromInstruction32(Insn, 4, 2))
3449         align = 4 << fieldFromInstruction32(Insn, 4, 2);
3450       index = fieldFromInstruction32(Insn, 7, 1);
3451       if (fieldFromInstruction32(Insn, 6, 1))
3452         inc = 2;
3453       break;
3454   }
3455 
3456   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3457     return MCDisassembler::Fail;
3458   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3459     return MCDisassembler::Fail;
3460   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3461     return MCDisassembler::Fail;
3462   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
3463     return MCDisassembler::Fail;
3464 
3465   if (Rm != 0xF) { // Writeback
3466     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3467       return MCDisassembler::Fail;
3468   }
3469   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3470     return MCDisassembler::Fail;
3471   Inst.addOperand(MCOperand::CreateImm(align));
3472   if (Rm != 0xF) {
3473     if (Rm != 0xD) {
3474       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3475         return MCDisassembler::Fail;
3476     } else
3477       Inst.addOperand(MCOperand::CreateReg(0));
3478   }
3479 
3480   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3481     return MCDisassembler::Fail;
3482   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3483     return MCDisassembler::Fail;
3484   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3485     return MCDisassembler::Fail;
3486   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
3487     return MCDisassembler::Fail;
3488   Inst.addOperand(MCOperand::CreateImm(index));
3489 
3490   return S;
3491 }
3492 
3493 static DecodeStatus DecodeVST4LN(llvm::MCInst &Inst, unsigned Insn,
3494                          uint64_t Address, const void *Decoder) {
3495   DecodeStatus S = MCDisassembler::Success;
3496 
3497   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3498   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3499   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3500   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3501   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3502 
3503   unsigned align = 0;
3504   unsigned index = 0;
3505   unsigned inc = 1;
3506   switch (size) {
3507     default:
3508       return MCDisassembler::Fail;
3509     case 0:
3510       if (fieldFromInstruction32(Insn, 4, 1))
3511         align = 4;
3512       index = fieldFromInstruction32(Insn, 5, 3);
3513       break;
3514     case 1:
3515       if (fieldFromInstruction32(Insn, 4, 1))
3516         align = 8;
3517       index = fieldFromInstruction32(Insn, 6, 2);
3518       if (fieldFromInstruction32(Insn, 5, 1))
3519         inc = 2;
3520       break;
3521     case 2:
3522       if (fieldFromInstruction32(Insn, 4, 2))
3523         align = 4 << fieldFromInstruction32(Insn, 4, 2);
3524       index = fieldFromInstruction32(Insn, 7, 1);
3525       if (fieldFromInstruction32(Insn, 6, 1))
3526         inc = 2;
3527       break;
3528   }
3529 
3530   if (Rm != 0xF) { // Writeback
3531     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3532     return MCDisassembler::Fail;
3533   }
3534   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3535     return MCDisassembler::Fail;
3536   Inst.addOperand(MCOperand::CreateImm(align));
3537   if (Rm != 0xF) {
3538     if (Rm != 0xD) {
3539       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3540     return MCDisassembler::Fail;
3541     } else
3542       Inst.addOperand(MCOperand::CreateReg(0));
3543   }
3544 
3545   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3546     return MCDisassembler::Fail;
3547   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3548     return MCDisassembler::Fail;
3549   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3550     return MCDisassembler::Fail;
3551   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
3552     return MCDisassembler::Fail;
3553   Inst.addOperand(MCOperand::CreateImm(index));
3554 
3555   return S;
3556 }
3557 
3558 static DecodeStatus DecodeVMOVSRR(llvm::MCInst &Inst, unsigned Insn,
3559                                   uint64_t Address, const void *Decoder) {
3560   DecodeStatus S = MCDisassembler::Success;
3561   unsigned Rt  = fieldFromInstruction32(Insn, 12, 4);
3562   unsigned Rt2 = fieldFromInstruction32(Insn, 16, 4);
3563   unsigned Rm  = fieldFromInstruction32(Insn,  0, 4);
3564   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3565   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
3566 
3567   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
3568     S = MCDisassembler::SoftFail;
3569 
3570   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
3571     return MCDisassembler::Fail;
3572   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
3573     return MCDisassembler::Fail;
3574   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
3575     return MCDisassembler::Fail;
3576   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
3577     return MCDisassembler::Fail;
3578   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3579     return MCDisassembler::Fail;
3580 
3581   return S;
3582 }
3583 
3584 static DecodeStatus DecodeVMOVRRS(llvm::MCInst &Inst, unsigned Insn,
3585                                   uint64_t Address, const void *Decoder) {
3586   DecodeStatus S = MCDisassembler::Success;
3587   unsigned Rt  = fieldFromInstruction32(Insn, 12, 4);
3588   unsigned Rt2 = fieldFromInstruction32(Insn, 16, 4);
3589   unsigned Rm  = fieldFromInstruction32(Insn,  0, 4);
3590   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3591   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
3592 
3593   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
3594     S = MCDisassembler::SoftFail;
3595 
3596   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
3597     return MCDisassembler::Fail;
3598   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
3599     return MCDisassembler::Fail;
3600   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
3601     return MCDisassembler::Fail;
3602   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
3603     return MCDisassembler::Fail;
3604   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3605     return MCDisassembler::Fail;
3606 
3607   return S;
3608 }
3609 
3610 static DecodeStatus DecodeIT(llvm::MCInst &Inst, unsigned Insn,
3611                              uint64_t Address, const void *Decoder) {
3612   DecodeStatus S = MCDisassembler::Success;
3613   unsigned pred = fieldFromInstruction16(Insn, 4, 4);
3614   // The InstPrinter needs to have the low bit of the predicate in
3615   // the mask operand to be able to print it properly.
3616   unsigned mask = fieldFromInstruction16(Insn, 0, 5);
3617 
3618   if (pred == 0xF) {
3619     pred = 0xE;
3620     S = MCDisassembler::SoftFail;
3621   }
3622 
3623   if ((mask & 0xF) == 0) {
3624     // Preserve the high bit of the mask, which is the low bit of
3625     // the predicate.
3626     mask &= 0x10;
3627     mask |= 0x8;
3628     S = MCDisassembler::SoftFail;
3629   }
3630 
3631   Inst.addOperand(MCOperand::CreateImm(pred));
3632   Inst.addOperand(MCOperand::CreateImm(mask));
3633   return S;
3634 }
3635