xref: /llvm-project/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp (revision a05627ebaf0bf5fbc1d666b677305212743699b1)
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   DecodeStatus 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 
101 // Forward declare these because the autogenerated code will reference them.
102 // Definitions are further down.
103 static DecodeStatus DecodeGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
104                                    uint64_t Address, const void *Decoder);
105 static DecodeStatus DecodeGPRnopcRegisterClass(llvm::MCInst &Inst,
106                                                unsigned RegNo, uint64_t Address,
107                                                const void *Decoder);
108 static DecodeStatus DecodetGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
109                                    uint64_t Address, const void *Decoder);
110 static DecodeStatus DecodetcGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
111                                    uint64_t Address, const void *Decoder);
112 static DecodeStatus DecoderGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
113                                    uint64_t Address, const void *Decoder);
114 static DecodeStatus DecodeSPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
115                                    uint64_t Address, const void *Decoder);
116 static DecodeStatus DecodeDPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
117                                    uint64_t Address, const void *Decoder);
118 static DecodeStatus DecodeDPR_8RegisterClass(llvm::MCInst &Inst, unsigned RegNo,
119                                    uint64_t Address, const void *Decoder);
120 static DecodeStatus DecodeDPR_VFP2RegisterClass(llvm::MCInst &Inst,
121                                                 unsigned RegNo,
122                                                 uint64_t Address,
123                                                 const void *Decoder);
124 static DecodeStatus DecodeQPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
125                                    uint64_t Address, const void *Decoder);
126 
127 static DecodeStatus DecodePredicateOperand(llvm::MCInst &Inst, unsigned Val,
128                                uint64_t Address, const void *Decoder);
129 static DecodeStatus DecodeCCOutOperand(llvm::MCInst &Inst, unsigned Val,
130                                uint64_t Address, const void *Decoder);
131 static DecodeStatus DecodeSOImmOperand(llvm::MCInst &Inst, unsigned Val,
132                                uint64_t Address, const void *Decoder);
133 static DecodeStatus DecodeRegListOperand(llvm::MCInst &Inst, unsigned Val,
134                                uint64_t Address, const void *Decoder);
135 static DecodeStatus DecodeSPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
136                                uint64_t Address, const void *Decoder);
137 static DecodeStatus DecodeDPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
138                                uint64_t Address, const void *Decoder);
139 
140 static DecodeStatus DecodeBitfieldMaskOperand(llvm::MCInst &Inst, unsigned Insn,
141                                uint64_t Address, const void *Decoder);
142 static DecodeStatus DecodeCopMemInstruction(llvm::MCInst &Inst, unsigned Insn,
143                                uint64_t Address, const void *Decoder);
144 static DecodeStatus DecodeAddrMode2IdxInstruction(llvm::MCInst &Inst,
145                                                   unsigned Insn,
146                                                   uint64_t Address,
147                                                   const void *Decoder);
148 static DecodeStatus DecodeSORegMemOperand(llvm::MCInst &Inst, unsigned Insn,
149                                uint64_t Address, const void *Decoder);
150 static DecodeStatus DecodeAddrMode3Instruction(llvm::MCInst &Inst,unsigned Insn,
151                                uint64_t Address, const void *Decoder);
152 static DecodeStatus DecodeSORegImmOperand(llvm::MCInst &Inst, unsigned Insn,
153                                uint64_t Address, const void *Decoder);
154 static DecodeStatus DecodeSORegRegOperand(llvm::MCInst &Inst, unsigned Insn,
155                                uint64_t Address, const void *Decoder);
156 
157 static DecodeStatus DecodeMemMultipleWritebackInstruction(llvm::MCInst & Inst,
158                                                   unsigned Insn,
159                                                   uint64_t Adddress,
160                                                   const void *Decoder);
161 static DecodeStatus DecodeSMLAInstruction(llvm::MCInst &Inst, unsigned Insn,
162                                uint64_t Address, const void *Decoder);
163 static DecodeStatus DecodeCPSInstruction(llvm::MCInst &Inst, unsigned Insn,
164                                uint64_t Address, const void *Decoder);
165 static DecodeStatus DecodeT2CPSInstruction(llvm::MCInst &Inst, unsigned Insn,
166                                uint64_t Address, const void *Decoder);
167 static DecodeStatus DecodeAddrModeImm12Operand(llvm::MCInst &Inst, unsigned Val,
168                                uint64_t Address, const void *Decoder);
169 static DecodeStatus DecodeAddrMode5Operand(llvm::MCInst &Inst, unsigned Val,
170                                uint64_t Address, const void *Decoder);
171 static DecodeStatus DecodeAddrMode7Operand(llvm::MCInst &Inst, unsigned Val,
172                                uint64_t Address, const void *Decoder);
173 static DecodeStatus DecodeBranchImmInstruction(llvm::MCInst &Inst,unsigned Insn,
174                                uint64_t Address, const void *Decoder);
175 static DecodeStatus DecodeVCVTImmOperand(llvm::MCInst &Inst, unsigned Val,
176                                uint64_t Address, const void *Decoder);
177 static DecodeStatus DecodeAddrMode6Operand(llvm::MCInst &Inst, unsigned Val,
178                                uint64_t Address, const void *Decoder);
179 static DecodeStatus DecodeVLDInstruction(llvm::MCInst &Inst, unsigned Val,
180                                uint64_t Address, const void *Decoder);
181 static DecodeStatus DecodeVSTInstruction(llvm::MCInst &Inst, unsigned Val,
182                                uint64_t Address, const void *Decoder);
183 static DecodeStatus DecodeVLD1DupInstruction(llvm::MCInst &Inst, unsigned Val,
184                                uint64_t Address, const void *Decoder);
185 static DecodeStatus DecodeVLD2DupInstruction(llvm::MCInst &Inst, unsigned Val,
186                                uint64_t Address, const void *Decoder);
187 static DecodeStatus DecodeVLD3DupInstruction(llvm::MCInst &Inst, unsigned Val,
188                                uint64_t Address, const void *Decoder);
189 static DecodeStatus DecodeVLD4DupInstruction(llvm::MCInst &Inst, unsigned Val,
190                                uint64_t Address, const void *Decoder);
191 static DecodeStatus DecodeNEONModImmInstruction(llvm::MCInst &Inst,unsigned Val,
192                                uint64_t Address, const void *Decoder);
193 static DecodeStatus DecodeVSHLMaxInstruction(llvm::MCInst &Inst, unsigned Val,
194                                uint64_t Address, const void *Decoder);
195 static DecodeStatus DecodeShiftRight8Imm(llvm::MCInst &Inst, unsigned Val,
196                                uint64_t Address, const void *Decoder);
197 static DecodeStatus DecodeShiftRight16Imm(llvm::MCInst &Inst, unsigned Val,
198                                uint64_t Address, const void *Decoder);
199 static DecodeStatus DecodeShiftRight32Imm(llvm::MCInst &Inst, unsigned Val,
200                                uint64_t Address, const void *Decoder);
201 static DecodeStatus DecodeShiftRight64Imm(llvm::MCInst &Inst, unsigned Val,
202                                uint64_t Address, const void *Decoder);
203 static DecodeStatus DecodeTBLInstruction(llvm::MCInst &Inst, unsigned Insn,
204                                uint64_t Address, const void *Decoder);
205 static DecodeStatus DecodeVFPfpImm(llvm::MCInst &Inst, unsigned Val,
206                                uint64_t Address, const void *Decoder);
207 static DecodeStatus DecodePostIdxReg(llvm::MCInst &Inst, unsigned Insn,
208                                uint64_t Address, const void *Decoder);
209 static DecodeStatus DecodeCoprocessor(llvm::MCInst &Inst, unsigned Insn,
210                                uint64_t Address, const void *Decoder);
211 static DecodeStatus DecodeMemBarrierOption(llvm::MCInst &Inst, unsigned Insn,
212                                uint64_t Address, const void *Decoder);
213 static DecodeStatus DecodeMSRMask(llvm::MCInst &Inst, unsigned Insn,
214                                uint64_t Address, const void *Decoder);
215 static DecodeStatus DecodeDoubleRegLoad(llvm::MCInst &Inst, unsigned Insn,
216                                uint64_t Address, const void *Decoder);
217 static DecodeStatus DecodeDoubleRegStore(llvm::MCInst &Inst, unsigned Insn,
218                                uint64_t Address, const void *Decoder);
219 static DecodeStatus DecodeLDRPreImm(llvm::MCInst &Inst, unsigned Insn,
220                                uint64_t Address, const void *Decoder);
221 static DecodeStatus DecodeLDRPreReg(llvm::MCInst &Inst, unsigned Insn,
222                                uint64_t Address, const void *Decoder);
223 static DecodeStatus DecodeSTRPreImm(llvm::MCInst &Inst, unsigned Insn,
224                                uint64_t Address, const void *Decoder);
225 static DecodeStatus DecodeSTRPreReg(llvm::MCInst &Inst, unsigned Insn,
226                                uint64_t Address, const void *Decoder);
227 static DecodeStatus DecodeVLD1LN(llvm::MCInst &Inst, unsigned Insn,
228                                uint64_t Address, const void *Decoder);
229 static DecodeStatus DecodeVLD2LN(llvm::MCInst &Inst, unsigned Insn,
230                                uint64_t Address, const void *Decoder);
231 static DecodeStatus DecodeVLD3LN(llvm::MCInst &Inst, unsigned Insn,
232                                uint64_t Address, const void *Decoder);
233 static DecodeStatus DecodeVLD4LN(llvm::MCInst &Inst, unsigned Insn,
234                                uint64_t Address, const void *Decoder);
235 static DecodeStatus DecodeVST1LN(llvm::MCInst &Inst, unsigned Insn,
236                                uint64_t Address, const void *Decoder);
237 static DecodeStatus DecodeVST2LN(llvm::MCInst &Inst, unsigned Insn,
238                                uint64_t Address, const void *Decoder);
239 static DecodeStatus DecodeVST3LN(llvm::MCInst &Inst, unsigned Insn,
240                                uint64_t Address, const void *Decoder);
241 static DecodeStatus DecodeVST4LN(llvm::MCInst &Inst, unsigned Insn,
242                                uint64_t Address, const void *Decoder);
243 static DecodeStatus DecodeVMOVSRR(llvm::MCInst &Inst, unsigned Insn,
244                                uint64_t Address, const void *Decoder);
245 static DecodeStatus DecodeVMOVRRS(llvm::MCInst &Inst, unsigned Insn,
246                                uint64_t Address, const void *Decoder);
247 
248 static DecodeStatus DecodeThumbAddSpecialReg(llvm::MCInst &Inst, uint16_t Insn,
249                                uint64_t Address, const void *Decoder);
250 static DecodeStatus DecodeThumbBROperand(llvm::MCInst &Inst, unsigned Val,
251                                uint64_t Address, const void *Decoder);
252 static DecodeStatus DecodeT2BROperand(llvm::MCInst &Inst, unsigned Val,
253                                uint64_t Address, const void *Decoder);
254 static DecodeStatus DecodeThumbCmpBROperand(llvm::MCInst &Inst, unsigned Val,
255                                uint64_t Address, const void *Decoder);
256 static DecodeStatus DecodeThumbAddrModeRR(llvm::MCInst &Inst, unsigned Val,
257                                uint64_t Address, const void *Decoder);
258 static DecodeStatus DecodeThumbAddrModeIS(llvm::MCInst &Inst, unsigned Val,
259                                uint64_t Address, const void *Decoder);
260 static DecodeStatus DecodeThumbAddrModePC(llvm::MCInst &Inst, unsigned Val,
261                                uint64_t Address, const void *Decoder);
262 static DecodeStatus DecodeThumbAddrModeSP(llvm::MCInst &Inst, unsigned Val,
263                                uint64_t Address, const void *Decoder);
264 static DecodeStatus DecodeT2AddrModeSOReg(llvm::MCInst &Inst, unsigned Val,
265                                uint64_t Address, const void *Decoder);
266 static DecodeStatus DecodeT2LoadShift(llvm::MCInst &Inst, unsigned Val,
267                                uint64_t Address, const void *Decoder);
268 static DecodeStatus DecodeT2Imm8S4(llvm::MCInst &Inst, unsigned Val,
269                                uint64_t Address, const void *Decoder);
270 static DecodeStatus DecodeT2AddrModeImm8s4(llvm::MCInst &Inst, unsigned Val,
271                                uint64_t Address, const void *Decoder);
272 static DecodeStatus DecodeT2AddrModeImm0_1020s4(llvm::MCInst &Inst,unsigned Val,
273                                uint64_t Address, const void *Decoder);
274 static DecodeStatus DecodeT2Imm8(llvm::MCInst &Inst, unsigned Val,
275                                uint64_t Address, const void *Decoder);
276 static DecodeStatus DecodeT2AddrModeImm8(llvm::MCInst &Inst, unsigned Val,
277                                uint64_t Address, const void *Decoder);
278 static DecodeStatus DecodeThumbAddSPImm(llvm::MCInst &Inst, uint16_t Val,
279                                uint64_t Address, const void *Decoder);
280 static DecodeStatus DecodeThumbAddSPReg(llvm::MCInst &Inst, uint16_t Insn,
281                                 uint64_t Address, const void *Decoder);
282 static DecodeStatus DecodeThumbCPS(llvm::MCInst &Inst, uint16_t Insn,
283                                 uint64_t Address, const void *Decoder);
284 static DecodeStatus DecodeThumbBLXOffset(llvm::MCInst &Inst, unsigned Insn,
285                                 uint64_t Address, const void *Decoder);
286 static DecodeStatus DecodeT2AddrModeImm12(llvm::MCInst &Inst, unsigned Val,
287                                 uint64_t Address, const void *Decoder);
288 static DecodeStatus DecodeThumb2BCCInstruction(llvm::MCInst &Inst, unsigned Val,
289                                 uint64_t Address, const void *Decoder);
290 static DecodeStatus DecodeT2SOImm(llvm::MCInst &Inst, unsigned Val,
291                                 uint64_t Address, const void *Decoder);
292 static DecodeStatus DecodeThumbBCCTargetOperand(llvm::MCInst &Inst,unsigned Val,
293                                 uint64_t Address, const void *Decoder);
294 static DecodeStatus DecodeThumbBLTargetOperand(llvm::MCInst &Inst, unsigned Val,
295                                 uint64_t Address, const void *Decoder);
296 static DecodeStatus DecodeIT(llvm::MCInst &Inst, unsigned Val,
297                                 uint64_t Address, const void *Decoder);
298 static DecodeStatus DecodeT2LDRDPreInstruction(llvm::MCInst &Inst,unsigned Insn,
299                                uint64_t Address, const void *Decoder);
300 static DecodeStatus DecodeT2STRDPreInstruction(llvm::MCInst &Inst,unsigned Insn,
301                                uint64_t Address, const void *Decoder);
302 
303 #include "ARMGenDisassemblerTables.inc"
304 #include "ARMGenInstrInfo.inc"
305 #include "ARMGenEDInfo.inc"
306 
307 static MCDisassembler *createARMDisassembler(const Target &T, const MCSubtargetInfo &STI) {
308   return new ARMDisassembler(STI);
309 }
310 
311 static MCDisassembler *createThumbDisassembler(const Target &T, const MCSubtargetInfo &STI) {
312   return new ThumbDisassembler(STI);
313 }
314 
315 EDInstInfo *ARMDisassembler::getEDInfo() const {
316   return instInfoARM;
317 }
318 
319 EDInstInfo *ThumbDisassembler::getEDInfo() const {
320   return instInfoARM;
321 }
322 
323 DecodeStatus ARMDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
324                                              const MemoryObject &Region,
325                                              uint64_t Address,
326                                              raw_ostream &os) const {
327   uint8_t bytes[4];
328 
329   assert(!(STI.getFeatureBits() & ARM::ModeThumb) &&
330          "Asked to disassemble an ARM instruction but Subtarget is in Thumb mode!");
331 
332   // We want to read exactly 4 bytes of data.
333   if (Region.readBytes(Address, 4, (uint8_t*)bytes, NULL) == -1) {
334     Size = 0;
335     return MCDisassembler::Fail;
336   }
337 
338   // Encoded as a small-endian 32-bit word in the stream.
339   uint32_t insn = (bytes[3] << 24) |
340                   (bytes[2] << 16) |
341                   (bytes[1] <<  8) |
342                   (bytes[0] <<  0);
343 
344   // Calling the auto-generated decoder function.
345   DecodeStatus result = decodeARMInstruction32(MI, insn, Address, this, STI);
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, STI);
355   if (result != MCDisassembler::Fail) {
356     Size = 4;
357     return result;
358   }
359 
360   MI.clear();
361   result = decodeNEONDataInstruction32(MI, insn, Address, this, STI);
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, STI);
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, STI);
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 MCDisassembler::DecodeStatus
428 ThumbDisassembler::AddThumbPredicate(MCInst &MI) const {
429   // A few instructions actually have predicates encoded in them.  Don't
430   // try to overwrite it if we're seeing one of those.
431   switch (MI.getOpcode()) {
432     case ARM::tBcc:
433     case ARM::t2Bcc:
434     case ARM::tCBZ:
435     case ARM::tCBNZ:
436       // Some instructions (mostly conditional branches) are not
437       // allowed in IT blocks.
438       if (!ITBlock.empty())
439         return SoftFail;
440       return Success;
441       break;
442     default:
443       break;
444   }
445 
446   // If we're in an IT block, base the predicate on that.  Otherwise,
447   // assume a predicate of AL.
448   unsigned CC;
449   if (!ITBlock.empty()) {
450     CC = ITBlock.back();
451     if (CC == 0xF)
452       CC = ARMCC::AL;
453     ITBlock.pop_back();
454   } else
455     CC = ARMCC::AL;
456 
457   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
458   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
459   MCInst::iterator I = MI.begin();
460   for (unsigned i = 0; i < NumOps; ++i, ++I) {
461     if (I == MI.end()) break;
462     if (OpInfo[i].isPredicate()) {
463       I = MI.insert(I, MCOperand::CreateImm(CC));
464       ++I;
465       if (CC == ARMCC::AL)
466         MI.insert(I, MCOperand::CreateReg(0));
467       else
468         MI.insert(I, MCOperand::CreateReg(ARM::CPSR));
469       return Success;
470     }
471   }
472 
473   I = MI.insert(I, MCOperand::CreateImm(CC));
474   ++I;
475   if (CC == ARMCC::AL)
476     MI.insert(I, MCOperand::CreateReg(0));
477   else
478     MI.insert(I, MCOperand::CreateReg(ARM::CPSR));
479 
480   return Success;
481 }
482 
483 // Thumb VFP instructions are a special case.  Because we share their
484 // encodings between ARM and Thumb modes, and they are predicable in ARM
485 // mode, the auto-generated decoder will give them an (incorrect)
486 // predicate operand.  We need to rewrite these operands based on the IT
487 // context as a post-pass.
488 void ThumbDisassembler::UpdateThumbVFPPredicate(MCInst &MI) const {
489   unsigned CC;
490   if (!ITBlock.empty()) {
491     CC = ITBlock.back();
492     ITBlock.pop_back();
493   } else
494     CC = ARMCC::AL;
495 
496   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
497   MCInst::iterator I = MI.begin();
498   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
499   for (unsigned i = 0; i < NumOps; ++i, ++I) {
500     if (OpInfo[i].isPredicate() ) {
501       I->setImm(CC);
502       ++I;
503       if (CC == ARMCC::AL)
504         I->setReg(0);
505       else
506         I->setReg(ARM::CPSR);
507       return;
508     }
509   }
510 }
511 
512 DecodeStatus ThumbDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
513                                                const MemoryObject &Region,
514                                                uint64_t Address,
515                                                raw_ostream &os) const {
516   uint8_t bytes[4];
517 
518   assert((STI.getFeatureBits() & ARM::ModeThumb) &&
519          "Asked to disassemble in Thumb mode but Subtarget is in ARM mode!");
520 
521   // We want to read exactly 2 bytes of data.
522   if (Region.readBytes(Address, 2, (uint8_t*)bytes, NULL) == -1) {
523     Size = 0;
524     return MCDisassembler::Fail;
525   }
526 
527   uint16_t insn16 = (bytes[1] << 8) | bytes[0];
528   DecodeStatus result = decodeThumbInstruction16(MI, insn16, Address, this, STI);
529   if (result != MCDisassembler::Fail) {
530     Size = 2;
531     Check(result, AddThumbPredicate(MI));
532     return result;
533   }
534 
535   MI.clear();
536   result = decodeThumbSBitInstruction16(MI, insn16, Address, this, STI);
537   if (result) {
538     Size = 2;
539     bool InITBlock = !ITBlock.empty();
540     Check(result, AddThumbPredicate(MI));
541     AddThumb1SBit(MI, InITBlock);
542     return result;
543   }
544 
545   MI.clear();
546   result = decodeThumb2Instruction16(MI, insn16, Address, this, STI);
547   if (result != MCDisassembler::Fail) {
548     Size = 2;
549     Check(result, AddThumbPredicate(MI));
550 
551     // If we find an IT instruction, we need to parse its condition
552     // code and mask operands so that we can apply them correctly
553     // to the subsequent instructions.
554     if (MI.getOpcode() == ARM::t2IT) {
555       // (3 - the number of trailing zeros) is the number of then / else.
556       unsigned firstcond = MI.getOperand(0).getImm();
557       unsigned Mask = MI.getOperand(1).getImm();
558       unsigned CondBit0 = Mask >> 4 & 1;
559       unsigned NumTZ = CountTrailingZeros_32(Mask);
560       assert(NumTZ <= 3 && "Invalid IT mask!");
561       for (unsigned Pos = 3, e = NumTZ; Pos > e; --Pos) {
562         bool T = ((Mask >> Pos) & 1) == CondBit0;
563         if (T)
564           ITBlock.insert(ITBlock.begin(), firstcond);
565         else
566           ITBlock.insert(ITBlock.begin(), firstcond ^ 1);
567       }
568 
569       ITBlock.push_back(firstcond);
570     }
571 
572     return result;
573   }
574 
575   // We want to read exactly 4 bytes of data.
576   if (Region.readBytes(Address, 4, (uint8_t*)bytes, NULL) == -1) {
577     Size = 0;
578     return MCDisassembler::Fail;
579   }
580 
581   uint32_t insn32 = (bytes[3] <<  8) |
582                     (bytes[2] <<  0) |
583                     (bytes[1] << 24) |
584                     (bytes[0] << 16);
585   MI.clear();
586   result = decodeThumbInstruction32(MI, insn32, Address, this, STI);
587   if (result != MCDisassembler::Fail) {
588     Size = 4;
589     bool InITBlock = ITBlock.size();
590     Check(result, AddThumbPredicate(MI));
591     AddThumb1SBit(MI, InITBlock);
592     return result;
593   }
594 
595   MI.clear();
596   result = decodeThumb2Instruction32(MI, insn32, Address, this, STI);
597   if (result != MCDisassembler::Fail) {
598     Size = 4;
599     Check(result, AddThumbPredicate(MI));
600     return result;
601   }
602 
603   MI.clear();
604   result = decodeVFPInstruction32(MI, insn32, Address, this, STI);
605   if (result != MCDisassembler::Fail) {
606     Size = 4;
607     UpdateThumbVFPPredicate(MI);
608     return result;
609   }
610 
611   MI.clear();
612   result = decodeNEONDupInstruction32(MI, insn32, Address, this, STI);
613   if (result != MCDisassembler::Fail) {
614     Size = 4;
615     Check(result, AddThumbPredicate(MI));
616     return result;
617   }
618 
619   if (fieldFromInstruction32(insn32, 24, 8) == 0xF9) {
620     MI.clear();
621     uint32_t NEONLdStInsn = insn32;
622     NEONLdStInsn &= 0xF0FFFFFF;
623     NEONLdStInsn |= 0x04000000;
624     result = decodeNEONLoadStoreInstruction32(MI, NEONLdStInsn, Address, this, STI);
625     if (result != MCDisassembler::Fail) {
626       Size = 4;
627       Check(result, AddThumbPredicate(MI));
628       return result;
629     }
630   }
631 
632   if (fieldFromInstruction32(insn32, 24, 4) == 0xF) {
633     MI.clear();
634     uint32_t NEONDataInsn = insn32;
635     NEONDataInsn &= 0xF0FFFFFF; // Clear bits 27-24
636     NEONDataInsn |= (NEONDataInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
637     NEONDataInsn |= 0x12000000; // Set bits 28 and 25
638     result = decodeNEONDataInstruction32(MI, NEONDataInsn, Address, this, STI);
639     if (result != MCDisassembler::Fail) {
640       Size = 4;
641       Check(result, AddThumbPredicate(MI));
642       return result;
643     }
644   }
645 
646   Size = 0;
647   return MCDisassembler::Fail;
648 }
649 
650 
651 extern "C" void LLVMInitializeARMDisassembler() {
652   TargetRegistry::RegisterMCDisassembler(TheARMTarget,
653                                          createARMDisassembler);
654   TargetRegistry::RegisterMCDisassembler(TheThumbTarget,
655                                          createThumbDisassembler);
656 }
657 
658 static const unsigned GPRDecoderTable[] = {
659   ARM::R0, ARM::R1, ARM::R2, ARM::R3,
660   ARM::R4, ARM::R5, ARM::R6, ARM::R7,
661   ARM::R8, ARM::R9, ARM::R10, ARM::R11,
662   ARM::R12, ARM::SP, ARM::LR, ARM::PC
663 };
664 
665 static DecodeStatus DecodeGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
666                                    uint64_t Address, const void *Decoder) {
667   if (RegNo > 15)
668     return MCDisassembler::Fail;
669 
670   unsigned Register = GPRDecoderTable[RegNo];
671   Inst.addOperand(MCOperand::CreateReg(Register));
672   return MCDisassembler::Success;
673 }
674 
675 static DecodeStatus
676 DecodeGPRnopcRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
677                            uint64_t Address, const void *Decoder) {
678   if (RegNo == 15) return MCDisassembler::Fail;
679   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
680 }
681 
682 static DecodeStatus DecodetGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
683                                    uint64_t Address, const void *Decoder) {
684   if (RegNo > 7)
685     return MCDisassembler::Fail;
686   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
687 }
688 
689 static DecodeStatus DecodetcGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
690                                    uint64_t Address, const void *Decoder) {
691   unsigned Register = 0;
692   switch (RegNo) {
693     case 0:
694       Register = ARM::R0;
695       break;
696     case 1:
697       Register = ARM::R1;
698       break;
699     case 2:
700       Register = ARM::R2;
701       break;
702     case 3:
703       Register = ARM::R3;
704       break;
705     case 9:
706       Register = ARM::R9;
707       break;
708     case 12:
709       Register = ARM::R12;
710       break;
711     default:
712       return MCDisassembler::Fail;
713     }
714 
715   Inst.addOperand(MCOperand::CreateReg(Register));
716   return MCDisassembler::Success;
717 }
718 
719 static DecodeStatus DecoderGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
720                                    uint64_t Address, const void *Decoder) {
721   if (RegNo == 13 || RegNo == 15) return MCDisassembler::Fail;
722   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
723 }
724 
725 static const unsigned SPRDecoderTable[] = {
726      ARM::S0,  ARM::S1,  ARM::S2,  ARM::S3,
727      ARM::S4,  ARM::S5,  ARM::S6,  ARM::S7,
728      ARM::S8,  ARM::S9, ARM::S10, ARM::S11,
729     ARM::S12, ARM::S13, ARM::S14, ARM::S15,
730     ARM::S16, ARM::S17, ARM::S18, ARM::S19,
731     ARM::S20, ARM::S21, ARM::S22, ARM::S23,
732     ARM::S24, ARM::S25, ARM::S26, ARM::S27,
733     ARM::S28, ARM::S29, ARM::S30, ARM::S31
734 };
735 
736 static DecodeStatus DecodeSPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
737                                    uint64_t Address, const void *Decoder) {
738   if (RegNo > 31)
739     return MCDisassembler::Fail;
740 
741   unsigned Register = SPRDecoderTable[RegNo];
742   Inst.addOperand(MCOperand::CreateReg(Register));
743   return MCDisassembler::Success;
744 }
745 
746 static const unsigned DPRDecoderTable[] = {
747      ARM::D0,  ARM::D1,  ARM::D2,  ARM::D3,
748      ARM::D4,  ARM::D5,  ARM::D6,  ARM::D7,
749      ARM::D8,  ARM::D9, ARM::D10, ARM::D11,
750     ARM::D12, ARM::D13, ARM::D14, ARM::D15,
751     ARM::D16, ARM::D17, ARM::D18, ARM::D19,
752     ARM::D20, ARM::D21, ARM::D22, ARM::D23,
753     ARM::D24, ARM::D25, ARM::D26, ARM::D27,
754     ARM::D28, ARM::D29, ARM::D30, ARM::D31
755 };
756 
757 static DecodeStatus DecodeDPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
758                                    uint64_t Address, const void *Decoder) {
759   if (RegNo > 31)
760     return MCDisassembler::Fail;
761 
762   unsigned Register = DPRDecoderTable[RegNo];
763   Inst.addOperand(MCOperand::CreateReg(Register));
764   return MCDisassembler::Success;
765 }
766 
767 static DecodeStatus DecodeDPR_8RegisterClass(llvm::MCInst &Inst, unsigned RegNo,
768                                    uint64_t Address, const void *Decoder) {
769   if (RegNo > 7)
770     return MCDisassembler::Fail;
771   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
772 }
773 
774 static DecodeStatus
775 DecodeDPR_VFP2RegisterClass(llvm::MCInst &Inst, unsigned RegNo,
776                             uint64_t Address, const void *Decoder) {
777   if (RegNo > 15)
778     return MCDisassembler::Fail;
779   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
780 }
781 
782 static const unsigned QPRDecoderTable[] = {
783      ARM::Q0,  ARM::Q1,  ARM::Q2,  ARM::Q3,
784      ARM::Q4,  ARM::Q5,  ARM::Q6,  ARM::Q7,
785      ARM::Q8,  ARM::Q9, ARM::Q10, ARM::Q11,
786     ARM::Q12, ARM::Q13, ARM::Q14, ARM::Q15
787 };
788 
789 
790 static DecodeStatus DecodeQPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
791                                    uint64_t Address, const void *Decoder) {
792   if (RegNo > 31)
793     return MCDisassembler::Fail;
794   RegNo >>= 1;
795 
796   unsigned Register = QPRDecoderTable[RegNo];
797   Inst.addOperand(MCOperand::CreateReg(Register));
798   return MCDisassembler::Success;
799 }
800 
801 static DecodeStatus DecodePredicateOperand(llvm::MCInst &Inst, unsigned Val,
802                                uint64_t Address, const void *Decoder) {
803   if (Val == 0xF) return MCDisassembler::Fail;
804   // AL predicate is not allowed on Thumb1 branches.
805   if (Inst.getOpcode() == ARM::tBcc && Val == 0xE)
806     return MCDisassembler::Fail;
807   Inst.addOperand(MCOperand::CreateImm(Val));
808   if (Val == ARMCC::AL) {
809     Inst.addOperand(MCOperand::CreateReg(0));
810   } else
811     Inst.addOperand(MCOperand::CreateReg(ARM::CPSR));
812   return MCDisassembler::Success;
813 }
814 
815 static DecodeStatus DecodeCCOutOperand(llvm::MCInst &Inst, unsigned Val,
816                                uint64_t Address, const void *Decoder) {
817   if (Val)
818     Inst.addOperand(MCOperand::CreateReg(ARM::CPSR));
819   else
820     Inst.addOperand(MCOperand::CreateReg(0));
821   return MCDisassembler::Success;
822 }
823 
824 static DecodeStatus DecodeSOImmOperand(llvm::MCInst &Inst, unsigned Val,
825                                uint64_t Address, const void *Decoder) {
826   uint32_t imm = Val & 0xFF;
827   uint32_t rot = (Val & 0xF00) >> 7;
828   uint32_t rot_imm = (imm >> rot) | (imm << (32-rot));
829   Inst.addOperand(MCOperand::CreateImm(rot_imm));
830   return MCDisassembler::Success;
831 }
832 
833 static DecodeStatus DecodeSORegImmOperand(llvm::MCInst &Inst, unsigned Val,
834                                uint64_t Address, const void *Decoder) {
835   DecodeStatus S = MCDisassembler::Success;
836 
837   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
838   unsigned type = fieldFromInstruction32(Val, 5, 2);
839   unsigned imm = fieldFromInstruction32(Val, 7, 5);
840 
841   // Register-immediate
842   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
843     return MCDisassembler::Fail;
844 
845   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
846   switch (type) {
847     case 0:
848       Shift = ARM_AM::lsl;
849       break;
850     case 1:
851       Shift = ARM_AM::lsr;
852       break;
853     case 2:
854       Shift = ARM_AM::asr;
855       break;
856     case 3:
857       Shift = ARM_AM::ror;
858       break;
859   }
860 
861   if (Shift == ARM_AM::ror && imm == 0)
862     Shift = ARM_AM::rrx;
863 
864   unsigned Op = Shift | (imm << 3);
865   Inst.addOperand(MCOperand::CreateImm(Op));
866 
867   return S;
868 }
869 
870 static DecodeStatus DecodeSORegRegOperand(llvm::MCInst &Inst, unsigned Val,
871                                uint64_t Address, const void *Decoder) {
872   DecodeStatus S = MCDisassembler::Success;
873 
874   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
875   unsigned type = fieldFromInstruction32(Val, 5, 2);
876   unsigned Rs = fieldFromInstruction32(Val, 8, 4);
877 
878   // Register-register
879   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
880     return MCDisassembler::Fail;
881   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rs, Address, Decoder)))
882     return MCDisassembler::Fail;
883 
884   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
885   switch (type) {
886     case 0:
887       Shift = ARM_AM::lsl;
888       break;
889     case 1:
890       Shift = ARM_AM::lsr;
891       break;
892     case 2:
893       Shift = ARM_AM::asr;
894       break;
895     case 3:
896       Shift = ARM_AM::ror;
897       break;
898   }
899 
900   Inst.addOperand(MCOperand::CreateImm(Shift));
901 
902   return S;
903 }
904 
905 static DecodeStatus DecodeRegListOperand(llvm::MCInst &Inst, unsigned Val,
906                                  uint64_t Address, const void *Decoder) {
907   DecodeStatus S = MCDisassembler::Success;
908 
909   // Empty register lists are not allowed.
910   if (CountPopulation_32(Val) == 0) return MCDisassembler::Fail;
911   for (unsigned i = 0; i < 16; ++i) {
912     if (Val & (1 << i)) {
913       if (!Check(S, DecodeGPRRegisterClass(Inst, i, Address, Decoder)))
914         return MCDisassembler::Fail;
915     }
916   }
917 
918   return S;
919 }
920 
921 static DecodeStatus DecodeSPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
922                                  uint64_t Address, const void *Decoder) {
923   DecodeStatus S = MCDisassembler::Success;
924 
925   unsigned Vd = fieldFromInstruction32(Val, 8, 4);
926   unsigned regs = Val & 0xFF;
927 
928   if (!Check(S, DecodeSPRRegisterClass(Inst, Vd, Address, Decoder)))
929     return MCDisassembler::Fail;
930   for (unsigned i = 0; i < (regs - 1); ++i) {
931     if (!Check(S, DecodeSPRRegisterClass(Inst, ++Vd, Address, Decoder)))
932       return MCDisassembler::Fail;
933   }
934 
935   return S;
936 }
937 
938 static DecodeStatus DecodeDPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
939                                  uint64_t Address, const void *Decoder) {
940   DecodeStatus S = MCDisassembler::Success;
941 
942   unsigned Vd = fieldFromInstruction32(Val, 8, 4);
943   unsigned regs = (Val & 0xFF) / 2;
944 
945   if (!Check(S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)))
946       return MCDisassembler::Fail;
947   for (unsigned i = 0; i < (regs - 1); ++i) {
948     if (!Check(S, DecodeDPRRegisterClass(Inst, ++Vd, Address, Decoder)))
949       return MCDisassembler::Fail;
950   }
951 
952   return S;
953 }
954 
955 static DecodeStatus DecodeBitfieldMaskOperand(llvm::MCInst &Inst, unsigned Val,
956                                       uint64_t Address, const void *Decoder) {
957   // This operand encodes a mask of contiguous zeros between a specified MSB
958   // and LSB.  To decode it, we create the mask of all bits MSB-and-lower,
959   // the mask of all bits LSB-and-lower, and then xor them to create
960   // the mask of that's all ones on [msb, lsb].  Finally we not it to
961   // create the final mask.
962   unsigned msb = fieldFromInstruction32(Val, 5, 5);
963   unsigned lsb = fieldFromInstruction32(Val, 0, 5);
964   uint32_t msb_mask = (1 << (msb+1)) - 1;
965   uint32_t lsb_mask = (1 << lsb) - 1;
966   Inst.addOperand(MCOperand::CreateImm(~(msb_mask ^ lsb_mask)));
967   return MCDisassembler::Success;
968 }
969 
970 static DecodeStatus DecodeCopMemInstruction(llvm::MCInst &Inst, unsigned Insn,
971                                   uint64_t Address, const void *Decoder) {
972   DecodeStatus S = MCDisassembler::Success;
973 
974   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
975   unsigned CRd = fieldFromInstruction32(Insn, 12, 4);
976   unsigned coproc = fieldFromInstruction32(Insn, 8, 4);
977   unsigned imm = fieldFromInstruction32(Insn, 0, 8);
978   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
979   unsigned U = fieldFromInstruction32(Insn, 23, 1);
980 
981   switch (Inst.getOpcode()) {
982     case ARM::LDC_OFFSET:
983     case ARM::LDC_PRE:
984     case ARM::LDC_POST:
985     case ARM::LDC_OPTION:
986     case ARM::LDCL_OFFSET:
987     case ARM::LDCL_PRE:
988     case ARM::LDCL_POST:
989     case ARM::LDCL_OPTION:
990     case ARM::STC_OFFSET:
991     case ARM::STC_PRE:
992     case ARM::STC_POST:
993     case ARM::STC_OPTION:
994     case ARM::STCL_OFFSET:
995     case ARM::STCL_PRE:
996     case ARM::STCL_POST:
997     case ARM::STCL_OPTION:
998     case ARM::t2LDC_OFFSET:
999     case ARM::t2LDC_PRE:
1000     case ARM::t2LDC_POST:
1001     case ARM::t2LDC_OPTION:
1002     case ARM::t2LDCL_OFFSET:
1003     case ARM::t2LDCL_PRE:
1004     case ARM::t2LDCL_POST:
1005     case ARM::t2LDCL_OPTION:
1006     case ARM::t2STC_OFFSET:
1007     case ARM::t2STC_PRE:
1008     case ARM::t2STC_POST:
1009     case ARM::t2STC_OPTION:
1010     case ARM::t2STCL_OFFSET:
1011     case ARM::t2STCL_PRE:
1012     case ARM::t2STCL_POST:
1013     case ARM::t2STCL_OPTION:
1014       if (coproc == 0xA || coproc == 0xB)
1015         return MCDisassembler::Fail;
1016       break;
1017     default:
1018       break;
1019   }
1020 
1021   Inst.addOperand(MCOperand::CreateImm(coproc));
1022   Inst.addOperand(MCOperand::CreateImm(CRd));
1023   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1024     return MCDisassembler::Fail;
1025   switch (Inst.getOpcode()) {
1026     case ARM::LDC_OPTION:
1027     case ARM::LDCL_OPTION:
1028     case ARM::LDC2_OPTION:
1029     case ARM::LDC2L_OPTION:
1030     case ARM::STC_OPTION:
1031     case ARM::STCL_OPTION:
1032     case ARM::STC2_OPTION:
1033     case ARM::STC2L_OPTION:
1034     case ARM::LDCL_POST:
1035     case ARM::STCL_POST:
1036     case ARM::LDC2L_POST:
1037     case ARM::STC2L_POST:
1038     case ARM::t2LDC_OPTION:
1039     case ARM::t2LDCL_OPTION:
1040     case ARM::t2STC_OPTION:
1041     case ARM::t2STCL_OPTION:
1042     case ARM::t2LDCL_POST:
1043     case ARM::t2STCL_POST:
1044       break;
1045     default:
1046       Inst.addOperand(MCOperand::CreateReg(0));
1047       break;
1048   }
1049 
1050   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1051   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1052 
1053   bool writeback = (P == 0) || (W == 1);
1054   unsigned idx_mode = 0;
1055   if (P && writeback)
1056     idx_mode = ARMII::IndexModePre;
1057   else if (!P && writeback)
1058     idx_mode = ARMII::IndexModePost;
1059 
1060   switch (Inst.getOpcode()) {
1061     case ARM::LDCL_POST:
1062     case ARM::STCL_POST:
1063     case ARM::t2LDCL_POST:
1064     case ARM::t2STCL_POST:
1065     case ARM::LDC2L_POST:
1066     case ARM::STC2L_POST:
1067       imm |= U << 8;
1068     case ARM::LDC_OPTION:
1069     case ARM::LDCL_OPTION:
1070     case ARM::LDC2_OPTION:
1071     case ARM::LDC2L_OPTION:
1072     case ARM::STC_OPTION:
1073     case ARM::STCL_OPTION:
1074     case ARM::STC2_OPTION:
1075     case ARM::STC2L_OPTION:
1076     case ARM::t2LDC_OPTION:
1077     case ARM::t2LDCL_OPTION:
1078     case ARM::t2STC_OPTION:
1079     case ARM::t2STCL_OPTION:
1080       Inst.addOperand(MCOperand::CreateImm(imm));
1081       break;
1082     default:
1083       if (U)
1084         Inst.addOperand(MCOperand::CreateImm(
1085             ARM_AM::getAM2Opc(ARM_AM::add, imm, ARM_AM::lsl, idx_mode)));
1086       else
1087         Inst.addOperand(MCOperand::CreateImm(
1088             ARM_AM::getAM2Opc(ARM_AM::sub, imm, ARM_AM::lsl, idx_mode)));
1089       break;
1090   }
1091 
1092   switch (Inst.getOpcode()) {
1093     case ARM::LDC_OFFSET:
1094     case ARM::LDC_PRE:
1095     case ARM::LDC_POST:
1096     case ARM::LDC_OPTION:
1097     case ARM::LDCL_OFFSET:
1098     case ARM::LDCL_PRE:
1099     case ARM::LDCL_POST:
1100     case ARM::LDCL_OPTION:
1101     case ARM::STC_OFFSET:
1102     case ARM::STC_PRE:
1103     case ARM::STC_POST:
1104     case ARM::STC_OPTION:
1105     case ARM::STCL_OFFSET:
1106     case ARM::STCL_PRE:
1107     case ARM::STCL_POST:
1108     case ARM::STCL_OPTION:
1109       if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1110         return MCDisassembler::Fail;
1111       break;
1112     default:
1113       break;
1114   }
1115 
1116   return S;
1117 }
1118 
1119 static DecodeStatus
1120 DecodeAddrMode2IdxInstruction(llvm::MCInst &Inst, unsigned Insn,
1121                               uint64_t Address, const void *Decoder) {
1122   DecodeStatus S = MCDisassembler::Success;
1123 
1124   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1125   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
1126   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1127   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
1128   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1129   unsigned reg = fieldFromInstruction32(Insn, 25, 1);
1130   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1131   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1132 
1133   // On stores, the writeback operand precedes Rt.
1134   switch (Inst.getOpcode()) {
1135     case ARM::STR_POST_IMM:
1136     case ARM::STR_POST_REG:
1137     case ARM::STRB_POST_IMM:
1138     case ARM::STRB_POST_REG:
1139     case ARM::STRT_POST_REG:
1140     case ARM::STRT_POST_IMM:
1141     case ARM::STRBT_POST_REG:
1142     case ARM::STRBT_POST_IMM:
1143       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1144         return MCDisassembler::Fail;
1145       break;
1146     default:
1147       break;
1148   }
1149 
1150   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
1151     return MCDisassembler::Fail;
1152 
1153   // On loads, the writeback operand comes after Rt.
1154   switch (Inst.getOpcode()) {
1155     case ARM::LDR_POST_IMM:
1156     case ARM::LDR_POST_REG:
1157     case ARM::LDRB_POST_IMM:
1158     case ARM::LDRB_POST_REG:
1159     case ARM::LDRBT_POST_REG:
1160     case ARM::LDRBT_POST_IMM:
1161     case ARM::LDRT_POST_REG:
1162     case ARM::LDRT_POST_IMM:
1163       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1164         return MCDisassembler::Fail;
1165       break;
1166     default:
1167       break;
1168   }
1169 
1170   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1171     return MCDisassembler::Fail;
1172 
1173   ARM_AM::AddrOpc Op = ARM_AM::add;
1174   if (!fieldFromInstruction32(Insn, 23, 1))
1175     Op = ARM_AM::sub;
1176 
1177   bool writeback = (P == 0) || (W == 1);
1178   unsigned idx_mode = 0;
1179   if (P && writeback)
1180     idx_mode = ARMII::IndexModePre;
1181   else if (!P && writeback)
1182     idx_mode = ARMII::IndexModePost;
1183 
1184   if (writeback && (Rn == 15 || Rn == Rt))
1185     S = MCDisassembler::SoftFail; // UNPREDICTABLE
1186 
1187   if (reg) {
1188     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1189       return MCDisassembler::Fail;
1190     ARM_AM::ShiftOpc Opc = ARM_AM::lsl;
1191     switch( fieldFromInstruction32(Insn, 5, 2)) {
1192       case 0:
1193         Opc = ARM_AM::lsl;
1194         break;
1195       case 1:
1196         Opc = ARM_AM::lsr;
1197         break;
1198       case 2:
1199         Opc = ARM_AM::asr;
1200         break;
1201       case 3:
1202         Opc = ARM_AM::ror;
1203         break;
1204       default:
1205         return MCDisassembler::Fail;
1206     }
1207     unsigned amt = fieldFromInstruction32(Insn, 7, 5);
1208     unsigned imm = ARM_AM::getAM2Opc(Op, amt, Opc, idx_mode);
1209 
1210     Inst.addOperand(MCOperand::CreateImm(imm));
1211   } else {
1212     Inst.addOperand(MCOperand::CreateReg(0));
1213     unsigned tmp = ARM_AM::getAM2Opc(Op, imm, ARM_AM::lsl, idx_mode);
1214     Inst.addOperand(MCOperand::CreateImm(tmp));
1215   }
1216 
1217   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1218     return MCDisassembler::Fail;
1219 
1220   return S;
1221 }
1222 
1223 static DecodeStatus DecodeSORegMemOperand(llvm::MCInst &Inst, unsigned Val,
1224                                   uint64_t Address, const void *Decoder) {
1225   DecodeStatus S = MCDisassembler::Success;
1226 
1227   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
1228   unsigned Rm = fieldFromInstruction32(Val,  0, 4);
1229   unsigned type = fieldFromInstruction32(Val, 5, 2);
1230   unsigned imm = fieldFromInstruction32(Val, 7, 5);
1231   unsigned U = fieldFromInstruction32(Val, 12, 1);
1232 
1233   ARM_AM::ShiftOpc ShOp = ARM_AM::lsl;
1234   switch (type) {
1235     case 0:
1236       ShOp = ARM_AM::lsl;
1237       break;
1238     case 1:
1239       ShOp = ARM_AM::lsr;
1240       break;
1241     case 2:
1242       ShOp = ARM_AM::asr;
1243       break;
1244     case 3:
1245       ShOp = ARM_AM::ror;
1246       break;
1247   }
1248 
1249   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1250     return MCDisassembler::Fail;
1251   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1252     return MCDisassembler::Fail;
1253   unsigned shift;
1254   if (U)
1255     shift = ARM_AM::getAM2Opc(ARM_AM::add, imm, ShOp);
1256   else
1257     shift = ARM_AM::getAM2Opc(ARM_AM::sub, imm, ShOp);
1258   Inst.addOperand(MCOperand::CreateImm(shift));
1259 
1260   return S;
1261 }
1262 
1263 static DecodeStatus
1264 DecodeAddrMode3Instruction(llvm::MCInst &Inst, unsigned Insn,
1265                            uint64_t Address, const void *Decoder) {
1266   DecodeStatus S = MCDisassembler::Success;
1267 
1268   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
1269   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1270   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1271   unsigned type = fieldFromInstruction32(Insn, 22, 1);
1272   unsigned imm = fieldFromInstruction32(Insn, 8, 4);
1273   unsigned U = ((~fieldFromInstruction32(Insn, 23, 1)) & 1) << 8;
1274   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1275   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1276   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1277 
1278   bool writeback = (W == 1) | (P == 0);
1279 
1280   // For {LD,ST}RD, Rt must be even, else undefined.
1281   switch (Inst.getOpcode()) {
1282     case ARM::STRD:
1283     case ARM::STRD_PRE:
1284     case ARM::STRD_POST:
1285     case ARM::LDRD:
1286     case ARM::LDRD_PRE:
1287     case ARM::LDRD_POST:
1288       if (Rt & 0x1) return MCDisassembler::Fail;
1289       break;
1290     default:
1291       break;
1292   }
1293 
1294   if (writeback) { // Writeback
1295     if (P)
1296       U |= ARMII::IndexModePre << 9;
1297     else
1298       U |= ARMII::IndexModePost << 9;
1299 
1300     // On stores, the writeback operand precedes Rt.
1301     switch (Inst.getOpcode()) {
1302     case ARM::STRD:
1303     case ARM::STRD_PRE:
1304     case ARM::STRD_POST:
1305     case ARM::STRH:
1306     case ARM::STRH_PRE:
1307     case ARM::STRH_POST:
1308       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1309         return MCDisassembler::Fail;
1310       break;
1311     default:
1312       break;
1313     }
1314   }
1315 
1316   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
1317     return MCDisassembler::Fail;
1318   switch (Inst.getOpcode()) {
1319     case ARM::STRD:
1320     case ARM::STRD_PRE:
1321     case ARM::STRD_POST:
1322     case ARM::LDRD:
1323     case ARM::LDRD_PRE:
1324     case ARM::LDRD_POST:
1325       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
1326         return MCDisassembler::Fail;
1327       break;
1328     default:
1329       break;
1330   }
1331 
1332   if (writeback) {
1333     // On loads, the writeback operand comes after Rt.
1334     switch (Inst.getOpcode()) {
1335     case ARM::LDRD:
1336     case ARM::LDRD_PRE:
1337     case ARM::LDRD_POST:
1338     case ARM::LDRH:
1339     case ARM::LDRH_PRE:
1340     case ARM::LDRH_POST:
1341     case ARM::LDRSH:
1342     case ARM::LDRSH_PRE:
1343     case ARM::LDRSH_POST:
1344     case ARM::LDRSB:
1345     case ARM::LDRSB_PRE:
1346     case ARM::LDRSB_POST:
1347     case ARM::LDRHTr:
1348     case ARM::LDRSBTr:
1349       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1350         return MCDisassembler::Fail;
1351       break;
1352     default:
1353       break;
1354     }
1355   }
1356 
1357   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1358     return MCDisassembler::Fail;
1359 
1360   if (type) {
1361     Inst.addOperand(MCOperand::CreateReg(0));
1362     Inst.addOperand(MCOperand::CreateImm(U | (imm << 4) | Rm));
1363   } else {
1364     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1365     return MCDisassembler::Fail;
1366     Inst.addOperand(MCOperand::CreateImm(U));
1367   }
1368 
1369   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1370     return MCDisassembler::Fail;
1371 
1372   return S;
1373 }
1374 
1375 static DecodeStatus DecodeRFEInstruction(llvm::MCInst &Inst, unsigned Insn,
1376                                  uint64_t Address, const void *Decoder) {
1377   DecodeStatus S = MCDisassembler::Success;
1378 
1379   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1380   unsigned mode = fieldFromInstruction32(Insn, 23, 2);
1381 
1382   switch (mode) {
1383     case 0:
1384       mode = ARM_AM::da;
1385       break;
1386     case 1:
1387       mode = ARM_AM::ia;
1388       break;
1389     case 2:
1390       mode = ARM_AM::db;
1391       break;
1392     case 3:
1393       mode = ARM_AM::ib;
1394       break;
1395   }
1396 
1397   Inst.addOperand(MCOperand::CreateImm(mode));
1398   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1399     return MCDisassembler::Fail;
1400 
1401   return S;
1402 }
1403 
1404 static DecodeStatus DecodeMemMultipleWritebackInstruction(llvm::MCInst &Inst,
1405                                   unsigned Insn,
1406                                   uint64_t Address, const void *Decoder) {
1407   DecodeStatus S = MCDisassembler::Success;
1408 
1409   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1410   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1411   unsigned reglist = fieldFromInstruction32(Insn, 0, 16);
1412 
1413   if (pred == 0xF) {
1414     switch (Inst.getOpcode()) {
1415       case ARM::LDMDA:
1416         Inst.setOpcode(ARM::RFEDA);
1417         break;
1418       case ARM::LDMDA_UPD:
1419         Inst.setOpcode(ARM::RFEDA_UPD);
1420         break;
1421       case ARM::LDMDB:
1422         Inst.setOpcode(ARM::RFEDB);
1423         break;
1424       case ARM::LDMDB_UPD:
1425         Inst.setOpcode(ARM::RFEDB_UPD);
1426         break;
1427       case ARM::LDMIA:
1428         Inst.setOpcode(ARM::RFEIA);
1429         break;
1430       case ARM::LDMIA_UPD:
1431         Inst.setOpcode(ARM::RFEIA_UPD);
1432         break;
1433       case ARM::LDMIB:
1434         Inst.setOpcode(ARM::RFEIB);
1435         break;
1436       case ARM::LDMIB_UPD:
1437         Inst.setOpcode(ARM::RFEIB_UPD);
1438         break;
1439       case ARM::STMDA:
1440         Inst.setOpcode(ARM::SRSDA);
1441         break;
1442       case ARM::STMDA_UPD:
1443         Inst.setOpcode(ARM::SRSDA_UPD);
1444         break;
1445       case ARM::STMDB:
1446         Inst.setOpcode(ARM::SRSDB);
1447         break;
1448       case ARM::STMDB_UPD:
1449         Inst.setOpcode(ARM::SRSDB_UPD);
1450         break;
1451       case ARM::STMIA:
1452         Inst.setOpcode(ARM::SRSIA);
1453         break;
1454       case ARM::STMIA_UPD:
1455         Inst.setOpcode(ARM::SRSIA_UPD);
1456         break;
1457       case ARM::STMIB:
1458         Inst.setOpcode(ARM::SRSIB);
1459         break;
1460       case ARM::STMIB_UPD:
1461         Inst.setOpcode(ARM::SRSIB_UPD);
1462         break;
1463       default:
1464         if (!Check(S, MCDisassembler::Fail)) return MCDisassembler::Fail;
1465     }
1466 
1467     // For stores (which become SRS's, the only operand is the mode.
1468     if (fieldFromInstruction32(Insn, 20, 1) == 0) {
1469       Inst.addOperand(
1470           MCOperand::CreateImm(fieldFromInstruction32(Insn, 0, 4)));
1471       return S;
1472     }
1473 
1474     return DecodeRFEInstruction(Inst, Insn, Address, Decoder);
1475   }
1476 
1477   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1478     return MCDisassembler::Fail;
1479   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1480     return MCDisassembler::Fail; // Tied
1481   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1482     return MCDisassembler::Fail;
1483   if (!Check(S, DecodeRegListOperand(Inst, reglist, Address, Decoder)))
1484     return MCDisassembler::Fail;
1485 
1486   return S;
1487 }
1488 
1489 static DecodeStatus DecodeCPSInstruction(llvm::MCInst &Inst, unsigned Insn,
1490                                  uint64_t Address, const void *Decoder) {
1491   unsigned imod = fieldFromInstruction32(Insn, 18, 2);
1492   unsigned M = fieldFromInstruction32(Insn, 17, 1);
1493   unsigned iflags = fieldFromInstruction32(Insn, 6, 3);
1494   unsigned mode = fieldFromInstruction32(Insn, 0, 5);
1495 
1496   DecodeStatus S = MCDisassembler::Success;
1497 
1498   // imod == '01' --> UNPREDICTABLE
1499   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
1500   // return failure here.  The '01' imod value is unprintable, so there's
1501   // nothing useful we could do even if we returned UNPREDICTABLE.
1502 
1503   if (imod == 1) return MCDisassembler::Fail;
1504 
1505   if (imod && M) {
1506     Inst.setOpcode(ARM::CPS3p);
1507     Inst.addOperand(MCOperand::CreateImm(imod));
1508     Inst.addOperand(MCOperand::CreateImm(iflags));
1509     Inst.addOperand(MCOperand::CreateImm(mode));
1510   } else if (imod && !M) {
1511     Inst.setOpcode(ARM::CPS2p);
1512     Inst.addOperand(MCOperand::CreateImm(imod));
1513     Inst.addOperand(MCOperand::CreateImm(iflags));
1514     if (mode) S = MCDisassembler::SoftFail;
1515   } else if (!imod && M) {
1516     Inst.setOpcode(ARM::CPS1p);
1517     Inst.addOperand(MCOperand::CreateImm(mode));
1518     if (iflags) S = MCDisassembler::SoftFail;
1519   } else {
1520     // imod == '00' && M == '0' --> UNPREDICTABLE
1521     Inst.setOpcode(ARM::CPS1p);
1522     Inst.addOperand(MCOperand::CreateImm(mode));
1523     S = MCDisassembler::SoftFail;
1524   }
1525 
1526   return S;
1527 }
1528 
1529 static DecodeStatus DecodeT2CPSInstruction(llvm::MCInst &Inst, unsigned Insn,
1530                                  uint64_t Address, const void *Decoder) {
1531   unsigned imod = fieldFromInstruction32(Insn, 9, 2);
1532   unsigned M = fieldFromInstruction32(Insn, 8, 1);
1533   unsigned iflags = fieldFromInstruction32(Insn, 5, 3);
1534   unsigned mode = fieldFromInstruction32(Insn, 0, 5);
1535 
1536   DecodeStatus S = MCDisassembler::Success;
1537 
1538   // imod == '01' --> UNPREDICTABLE
1539   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
1540   // return failure here.  The '01' imod value is unprintable, so there's
1541   // nothing useful we could do even if we returned UNPREDICTABLE.
1542 
1543   if (imod == 1) return MCDisassembler::Fail;
1544 
1545   if (imod && M) {
1546     Inst.setOpcode(ARM::t2CPS3p);
1547     Inst.addOperand(MCOperand::CreateImm(imod));
1548     Inst.addOperand(MCOperand::CreateImm(iflags));
1549     Inst.addOperand(MCOperand::CreateImm(mode));
1550   } else if (imod && !M) {
1551     Inst.setOpcode(ARM::t2CPS2p);
1552     Inst.addOperand(MCOperand::CreateImm(imod));
1553     Inst.addOperand(MCOperand::CreateImm(iflags));
1554     if (mode) S = MCDisassembler::SoftFail;
1555   } else if (!imod && M) {
1556     Inst.setOpcode(ARM::t2CPS1p);
1557     Inst.addOperand(MCOperand::CreateImm(mode));
1558     if (iflags) S = MCDisassembler::SoftFail;
1559   } else {
1560     // imod == '00' && M == '0' --> UNPREDICTABLE
1561     Inst.setOpcode(ARM::t2CPS1p);
1562     Inst.addOperand(MCOperand::CreateImm(mode));
1563     S = MCDisassembler::SoftFail;
1564   }
1565 
1566   return S;
1567 }
1568 
1569 
1570 static DecodeStatus DecodeSMLAInstruction(llvm::MCInst &Inst, unsigned Insn,
1571                                  uint64_t Address, const void *Decoder) {
1572   DecodeStatus S = MCDisassembler::Success;
1573 
1574   unsigned Rd = fieldFromInstruction32(Insn, 16, 4);
1575   unsigned Rn = fieldFromInstruction32(Insn, 0, 4);
1576   unsigned Rm = fieldFromInstruction32(Insn, 8, 4);
1577   unsigned Ra = fieldFromInstruction32(Insn, 12, 4);
1578   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1579 
1580   if (pred == 0xF)
1581     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
1582 
1583   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
1584     return MCDisassembler::Fail;
1585   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
1586     return MCDisassembler::Fail;
1587   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1588     return MCDisassembler::Fail;
1589   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Ra, Address, Decoder)))
1590     return MCDisassembler::Fail;
1591 
1592   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1593     return MCDisassembler::Fail;
1594 
1595   return S;
1596 }
1597 
1598 static DecodeStatus DecodeAddrModeImm12Operand(llvm::MCInst &Inst, unsigned Val,
1599                            uint64_t Address, const void *Decoder) {
1600   DecodeStatus S = MCDisassembler::Success;
1601 
1602   unsigned add = fieldFromInstruction32(Val, 12, 1);
1603   unsigned imm = fieldFromInstruction32(Val, 0, 12);
1604   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
1605 
1606   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1607     return MCDisassembler::Fail;
1608 
1609   if (!add) imm *= -1;
1610   if (imm == 0 && !add) imm = INT32_MIN;
1611   Inst.addOperand(MCOperand::CreateImm(imm));
1612 
1613   return S;
1614 }
1615 
1616 static DecodeStatus DecodeAddrMode5Operand(llvm::MCInst &Inst, unsigned Val,
1617                                    uint64_t Address, const void *Decoder) {
1618   DecodeStatus S = MCDisassembler::Success;
1619 
1620   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
1621   unsigned U = fieldFromInstruction32(Val, 8, 1);
1622   unsigned imm = fieldFromInstruction32(Val, 0, 8);
1623 
1624   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1625     return MCDisassembler::Fail;
1626 
1627   if (U)
1628     Inst.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(ARM_AM::add, imm)));
1629   else
1630     Inst.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(ARM_AM::sub, imm)));
1631 
1632   return S;
1633 }
1634 
1635 static DecodeStatus DecodeAddrMode7Operand(llvm::MCInst &Inst, unsigned Val,
1636                                    uint64_t Address, const void *Decoder) {
1637   return DecodeGPRRegisterClass(Inst, Val, Address, Decoder);
1638 }
1639 
1640 static DecodeStatus
1641 DecodeBranchImmInstruction(llvm::MCInst &Inst, unsigned Insn,
1642                            uint64_t Address, const void *Decoder) {
1643   DecodeStatus S = MCDisassembler::Success;
1644 
1645   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1646   unsigned imm = fieldFromInstruction32(Insn, 0, 24) << 2;
1647 
1648   if (pred == 0xF) {
1649     Inst.setOpcode(ARM::BLXi);
1650     imm |= fieldFromInstruction32(Insn, 24, 1) << 1;
1651     Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(imm)));
1652     return S;
1653   }
1654 
1655   Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(imm)));
1656   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1657     return MCDisassembler::Fail;
1658 
1659   return S;
1660 }
1661 
1662 
1663 static DecodeStatus DecodeVCVTImmOperand(llvm::MCInst &Inst, unsigned Val,
1664                                  uint64_t Address, const void *Decoder) {
1665   Inst.addOperand(MCOperand::CreateImm(64 - Val));
1666   return MCDisassembler::Success;
1667 }
1668 
1669 static DecodeStatus DecodeAddrMode6Operand(llvm::MCInst &Inst, unsigned Val,
1670                                    uint64_t Address, const void *Decoder) {
1671   DecodeStatus S = MCDisassembler::Success;
1672 
1673   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
1674   unsigned align = fieldFromInstruction32(Val, 4, 2);
1675 
1676   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1677     return MCDisassembler::Fail;
1678   if (!align)
1679     Inst.addOperand(MCOperand::CreateImm(0));
1680   else
1681     Inst.addOperand(MCOperand::CreateImm(4 << align));
1682 
1683   return S;
1684 }
1685 
1686 static DecodeStatus DecodeVLDInstruction(llvm::MCInst &Inst, unsigned Insn,
1687                                    uint64_t Address, const void *Decoder) {
1688   DecodeStatus S = MCDisassembler::Success;
1689 
1690   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
1691   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
1692   unsigned wb = fieldFromInstruction32(Insn, 16, 4);
1693   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1694   Rn |= fieldFromInstruction32(Insn, 4, 2) << 4;
1695   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1696 
1697   // First output register
1698   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
1699     return MCDisassembler::Fail;
1700 
1701   // Second output register
1702   switch (Inst.getOpcode()) {
1703     case ARM::VLD1q8:
1704     case ARM::VLD1q16:
1705     case ARM::VLD1q32:
1706     case ARM::VLD1q64:
1707     case ARM::VLD1q8_UPD:
1708     case ARM::VLD1q16_UPD:
1709     case ARM::VLD1q32_UPD:
1710     case ARM::VLD1q64_UPD:
1711     case ARM::VLD1d8T:
1712     case ARM::VLD1d16T:
1713     case ARM::VLD1d32T:
1714     case ARM::VLD1d64T:
1715     case ARM::VLD1d8T_UPD:
1716     case ARM::VLD1d16T_UPD:
1717     case ARM::VLD1d32T_UPD:
1718     case ARM::VLD1d64T_UPD:
1719     case ARM::VLD1d8Q:
1720     case ARM::VLD1d16Q:
1721     case ARM::VLD1d32Q:
1722     case ARM::VLD1d64Q:
1723     case ARM::VLD1d8Q_UPD:
1724     case ARM::VLD1d16Q_UPD:
1725     case ARM::VLD1d32Q_UPD:
1726     case ARM::VLD1d64Q_UPD:
1727     case ARM::VLD2d8:
1728     case ARM::VLD2d16:
1729     case ARM::VLD2d32:
1730     case ARM::VLD2d8_UPD:
1731     case ARM::VLD2d16_UPD:
1732     case ARM::VLD2d32_UPD:
1733     case ARM::VLD2q8:
1734     case ARM::VLD2q16:
1735     case ARM::VLD2q32:
1736     case ARM::VLD2q8_UPD:
1737     case ARM::VLD2q16_UPD:
1738     case ARM::VLD2q32_UPD:
1739     case ARM::VLD3d8:
1740     case ARM::VLD3d16:
1741     case ARM::VLD3d32:
1742     case ARM::VLD3d8_UPD:
1743     case ARM::VLD3d16_UPD:
1744     case ARM::VLD3d32_UPD:
1745     case ARM::VLD4d8:
1746     case ARM::VLD4d16:
1747     case ARM::VLD4d32:
1748     case ARM::VLD4d8_UPD:
1749     case ARM::VLD4d16_UPD:
1750     case ARM::VLD4d32_UPD:
1751       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
1752         return MCDisassembler::Fail;
1753       break;
1754     case ARM::VLD2b8:
1755     case ARM::VLD2b16:
1756     case ARM::VLD2b32:
1757     case ARM::VLD2b8_UPD:
1758     case ARM::VLD2b16_UPD:
1759     case ARM::VLD2b32_UPD:
1760     case ARM::VLD3q8:
1761     case ARM::VLD3q16:
1762     case ARM::VLD3q32:
1763     case ARM::VLD3q8_UPD:
1764     case ARM::VLD3q16_UPD:
1765     case ARM::VLD3q32_UPD:
1766     case ARM::VLD4q8:
1767     case ARM::VLD4q16:
1768     case ARM::VLD4q32:
1769     case ARM::VLD4q8_UPD:
1770     case ARM::VLD4q16_UPD:
1771     case ARM::VLD4q32_UPD:
1772       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
1773         return MCDisassembler::Fail;
1774     default:
1775       break;
1776   }
1777 
1778   // Third output register
1779   switch(Inst.getOpcode()) {
1780     case ARM::VLD1d8T:
1781     case ARM::VLD1d16T:
1782     case ARM::VLD1d32T:
1783     case ARM::VLD1d64T:
1784     case ARM::VLD1d8T_UPD:
1785     case ARM::VLD1d16T_UPD:
1786     case ARM::VLD1d32T_UPD:
1787     case ARM::VLD1d64T_UPD:
1788     case ARM::VLD1d8Q:
1789     case ARM::VLD1d16Q:
1790     case ARM::VLD1d32Q:
1791     case ARM::VLD1d64Q:
1792     case ARM::VLD1d8Q_UPD:
1793     case ARM::VLD1d16Q_UPD:
1794     case ARM::VLD1d32Q_UPD:
1795     case ARM::VLD1d64Q_UPD:
1796     case ARM::VLD2q8:
1797     case ARM::VLD2q16:
1798     case ARM::VLD2q32:
1799     case ARM::VLD2q8_UPD:
1800     case ARM::VLD2q16_UPD:
1801     case ARM::VLD2q32_UPD:
1802     case ARM::VLD3d8:
1803     case ARM::VLD3d16:
1804     case ARM::VLD3d32:
1805     case ARM::VLD3d8_UPD:
1806     case ARM::VLD3d16_UPD:
1807     case ARM::VLD3d32_UPD:
1808     case ARM::VLD4d8:
1809     case ARM::VLD4d16:
1810     case ARM::VLD4d32:
1811     case ARM::VLD4d8_UPD:
1812     case ARM::VLD4d16_UPD:
1813     case ARM::VLD4d32_UPD:
1814       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
1815         return MCDisassembler::Fail;
1816       break;
1817     case ARM::VLD3q8:
1818     case ARM::VLD3q16:
1819     case ARM::VLD3q32:
1820     case ARM::VLD3q8_UPD:
1821     case ARM::VLD3q16_UPD:
1822     case ARM::VLD3q32_UPD:
1823     case ARM::VLD4q8:
1824     case ARM::VLD4q16:
1825     case ARM::VLD4q32:
1826     case ARM::VLD4q8_UPD:
1827     case ARM::VLD4q16_UPD:
1828     case ARM::VLD4q32_UPD:
1829       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
1830         return MCDisassembler::Fail;
1831       break;
1832     default:
1833       break;
1834   }
1835 
1836   // Fourth output register
1837   switch (Inst.getOpcode()) {
1838     case ARM::VLD1d8Q:
1839     case ARM::VLD1d16Q:
1840     case ARM::VLD1d32Q:
1841     case ARM::VLD1d64Q:
1842     case ARM::VLD1d8Q_UPD:
1843     case ARM::VLD1d16Q_UPD:
1844     case ARM::VLD1d32Q_UPD:
1845     case ARM::VLD1d64Q_UPD:
1846     case ARM::VLD2q8:
1847     case ARM::VLD2q16:
1848     case ARM::VLD2q32:
1849     case ARM::VLD2q8_UPD:
1850     case ARM::VLD2q16_UPD:
1851     case ARM::VLD2q32_UPD:
1852     case ARM::VLD4d8:
1853     case ARM::VLD4d16:
1854     case ARM::VLD4d32:
1855     case ARM::VLD4d8_UPD:
1856     case ARM::VLD4d16_UPD:
1857     case ARM::VLD4d32_UPD:
1858       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
1859         return MCDisassembler::Fail;
1860       break;
1861     case ARM::VLD4q8:
1862     case ARM::VLD4q16:
1863     case ARM::VLD4q32:
1864     case ARM::VLD4q8_UPD:
1865     case ARM::VLD4q16_UPD:
1866     case ARM::VLD4q32_UPD:
1867       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
1868         return MCDisassembler::Fail;
1869       break;
1870     default:
1871       break;
1872   }
1873 
1874   // Writeback operand
1875   switch (Inst.getOpcode()) {
1876     case ARM::VLD1d8_UPD:
1877     case ARM::VLD1d16_UPD:
1878     case ARM::VLD1d32_UPD:
1879     case ARM::VLD1d64_UPD:
1880     case ARM::VLD1q8_UPD:
1881     case ARM::VLD1q16_UPD:
1882     case ARM::VLD1q32_UPD:
1883     case ARM::VLD1q64_UPD:
1884     case ARM::VLD1d8T_UPD:
1885     case ARM::VLD1d16T_UPD:
1886     case ARM::VLD1d32T_UPD:
1887     case ARM::VLD1d64T_UPD:
1888     case ARM::VLD1d8Q_UPD:
1889     case ARM::VLD1d16Q_UPD:
1890     case ARM::VLD1d32Q_UPD:
1891     case ARM::VLD1d64Q_UPD:
1892     case ARM::VLD2d8_UPD:
1893     case ARM::VLD2d16_UPD:
1894     case ARM::VLD2d32_UPD:
1895     case ARM::VLD2q8_UPD:
1896     case ARM::VLD2q16_UPD:
1897     case ARM::VLD2q32_UPD:
1898     case ARM::VLD2b8_UPD:
1899     case ARM::VLD2b16_UPD:
1900     case ARM::VLD2b32_UPD:
1901     case ARM::VLD3d8_UPD:
1902     case ARM::VLD3d16_UPD:
1903     case ARM::VLD3d32_UPD:
1904     case ARM::VLD3q8_UPD:
1905     case ARM::VLD3q16_UPD:
1906     case ARM::VLD3q32_UPD:
1907     case ARM::VLD4d8_UPD:
1908     case ARM::VLD4d16_UPD:
1909     case ARM::VLD4d32_UPD:
1910     case ARM::VLD4q8_UPD:
1911     case ARM::VLD4q16_UPD:
1912     case ARM::VLD4q32_UPD:
1913       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
1914         return MCDisassembler::Fail;
1915       break;
1916     default:
1917       break;
1918   }
1919 
1920   // AddrMode6 Base (register+alignment)
1921   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
1922     return MCDisassembler::Fail;
1923 
1924   // AddrMode6 Offset (register)
1925   if (Rm == 0xD)
1926     Inst.addOperand(MCOperand::CreateReg(0));
1927   else if (Rm != 0xF) {
1928     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1929       return MCDisassembler::Fail;
1930   }
1931 
1932   return S;
1933 }
1934 
1935 static DecodeStatus DecodeVSTInstruction(llvm::MCInst &Inst, unsigned Insn,
1936                                  uint64_t Address, const void *Decoder) {
1937   DecodeStatus S = MCDisassembler::Success;
1938 
1939   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
1940   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
1941   unsigned wb = fieldFromInstruction32(Insn, 16, 4);
1942   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1943   Rn |= fieldFromInstruction32(Insn, 4, 2) << 4;
1944   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1945 
1946   // Writeback Operand
1947   switch (Inst.getOpcode()) {
1948     case ARM::VST1d8_UPD:
1949     case ARM::VST1d16_UPD:
1950     case ARM::VST1d32_UPD:
1951     case ARM::VST1d64_UPD:
1952     case ARM::VST1q8_UPD:
1953     case ARM::VST1q16_UPD:
1954     case ARM::VST1q32_UPD:
1955     case ARM::VST1q64_UPD:
1956     case ARM::VST1d8T_UPD:
1957     case ARM::VST1d16T_UPD:
1958     case ARM::VST1d32T_UPD:
1959     case ARM::VST1d64T_UPD:
1960     case ARM::VST1d8Q_UPD:
1961     case ARM::VST1d16Q_UPD:
1962     case ARM::VST1d32Q_UPD:
1963     case ARM::VST1d64Q_UPD:
1964     case ARM::VST2d8_UPD:
1965     case ARM::VST2d16_UPD:
1966     case ARM::VST2d32_UPD:
1967     case ARM::VST2q8_UPD:
1968     case ARM::VST2q16_UPD:
1969     case ARM::VST2q32_UPD:
1970     case ARM::VST2b8_UPD:
1971     case ARM::VST2b16_UPD:
1972     case ARM::VST2b32_UPD:
1973     case ARM::VST3d8_UPD:
1974     case ARM::VST3d16_UPD:
1975     case ARM::VST3d32_UPD:
1976     case ARM::VST3q8_UPD:
1977     case ARM::VST3q16_UPD:
1978     case ARM::VST3q32_UPD:
1979     case ARM::VST4d8_UPD:
1980     case ARM::VST4d16_UPD:
1981     case ARM::VST4d32_UPD:
1982     case ARM::VST4q8_UPD:
1983     case ARM::VST4q16_UPD:
1984     case ARM::VST4q32_UPD:
1985       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
1986         return MCDisassembler::Fail;
1987       break;
1988     default:
1989       break;
1990   }
1991 
1992   // AddrMode6 Base (register+alignment)
1993   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
1994     return MCDisassembler::Fail;
1995 
1996   // AddrMode6 Offset (register)
1997   if (Rm == 0xD)
1998     Inst.addOperand(MCOperand::CreateReg(0));
1999   else if (Rm != 0xF) {
2000     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2001     return MCDisassembler::Fail;
2002   }
2003 
2004   // First input register
2005   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2006     return MCDisassembler::Fail;
2007 
2008   // Second input register
2009   switch (Inst.getOpcode()) {
2010     case ARM::VST1q8:
2011     case ARM::VST1q16:
2012     case ARM::VST1q32:
2013     case ARM::VST1q64:
2014     case ARM::VST1q8_UPD:
2015     case ARM::VST1q16_UPD:
2016     case ARM::VST1q32_UPD:
2017     case ARM::VST1q64_UPD:
2018     case ARM::VST1d8T:
2019     case ARM::VST1d16T:
2020     case ARM::VST1d32T:
2021     case ARM::VST1d64T:
2022     case ARM::VST1d8T_UPD:
2023     case ARM::VST1d16T_UPD:
2024     case ARM::VST1d32T_UPD:
2025     case ARM::VST1d64T_UPD:
2026     case ARM::VST1d8Q:
2027     case ARM::VST1d16Q:
2028     case ARM::VST1d32Q:
2029     case ARM::VST1d64Q:
2030     case ARM::VST1d8Q_UPD:
2031     case ARM::VST1d16Q_UPD:
2032     case ARM::VST1d32Q_UPD:
2033     case ARM::VST1d64Q_UPD:
2034     case ARM::VST2d8:
2035     case ARM::VST2d16:
2036     case ARM::VST2d32:
2037     case ARM::VST2d8_UPD:
2038     case ARM::VST2d16_UPD:
2039     case ARM::VST2d32_UPD:
2040     case ARM::VST2q8:
2041     case ARM::VST2q16:
2042     case ARM::VST2q32:
2043     case ARM::VST2q8_UPD:
2044     case ARM::VST2q16_UPD:
2045     case ARM::VST2q32_UPD:
2046     case ARM::VST3d8:
2047     case ARM::VST3d16:
2048     case ARM::VST3d32:
2049     case ARM::VST3d8_UPD:
2050     case ARM::VST3d16_UPD:
2051     case ARM::VST3d32_UPD:
2052     case ARM::VST4d8:
2053     case ARM::VST4d16:
2054     case ARM::VST4d32:
2055     case ARM::VST4d8_UPD:
2056     case ARM::VST4d16_UPD:
2057     case ARM::VST4d32_UPD:
2058       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
2059         return MCDisassembler::Fail;
2060       break;
2061     case ARM::VST2b8:
2062     case ARM::VST2b16:
2063     case ARM::VST2b32:
2064     case ARM::VST2b8_UPD:
2065     case ARM::VST2b16_UPD:
2066     case ARM::VST2b32_UPD:
2067     case ARM::VST3q8:
2068     case ARM::VST3q16:
2069     case ARM::VST3q32:
2070     case ARM::VST3q8_UPD:
2071     case ARM::VST3q16_UPD:
2072     case ARM::VST3q32_UPD:
2073     case ARM::VST4q8:
2074     case ARM::VST4q16:
2075     case ARM::VST4q32:
2076     case ARM::VST4q8_UPD:
2077     case ARM::VST4q16_UPD:
2078     case ARM::VST4q32_UPD:
2079       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2080         return MCDisassembler::Fail;
2081       break;
2082     default:
2083       break;
2084   }
2085 
2086   // Third input register
2087   switch (Inst.getOpcode()) {
2088     case ARM::VST1d8T:
2089     case ARM::VST1d16T:
2090     case ARM::VST1d32T:
2091     case ARM::VST1d64T:
2092     case ARM::VST1d8T_UPD:
2093     case ARM::VST1d16T_UPD:
2094     case ARM::VST1d32T_UPD:
2095     case ARM::VST1d64T_UPD:
2096     case ARM::VST1d8Q:
2097     case ARM::VST1d16Q:
2098     case ARM::VST1d32Q:
2099     case ARM::VST1d64Q:
2100     case ARM::VST1d8Q_UPD:
2101     case ARM::VST1d16Q_UPD:
2102     case ARM::VST1d32Q_UPD:
2103     case ARM::VST1d64Q_UPD:
2104     case ARM::VST2q8:
2105     case ARM::VST2q16:
2106     case ARM::VST2q32:
2107     case ARM::VST2q8_UPD:
2108     case ARM::VST2q16_UPD:
2109     case ARM::VST2q32_UPD:
2110     case ARM::VST3d8:
2111     case ARM::VST3d16:
2112     case ARM::VST3d32:
2113     case ARM::VST3d8_UPD:
2114     case ARM::VST3d16_UPD:
2115     case ARM::VST3d32_UPD:
2116     case ARM::VST4d8:
2117     case ARM::VST4d16:
2118     case ARM::VST4d32:
2119     case ARM::VST4d8_UPD:
2120     case ARM::VST4d16_UPD:
2121     case ARM::VST4d32_UPD:
2122       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2123         return MCDisassembler::Fail;
2124       break;
2125     case ARM::VST3q8:
2126     case ARM::VST3q16:
2127     case ARM::VST3q32:
2128     case ARM::VST3q8_UPD:
2129     case ARM::VST3q16_UPD:
2130     case ARM::VST3q32_UPD:
2131     case ARM::VST4q8:
2132     case ARM::VST4q16:
2133     case ARM::VST4q32:
2134     case ARM::VST4q8_UPD:
2135     case ARM::VST4q16_UPD:
2136     case ARM::VST4q32_UPD:
2137       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
2138         return MCDisassembler::Fail;
2139       break;
2140     default:
2141       break;
2142   }
2143 
2144   // Fourth input register
2145   switch (Inst.getOpcode()) {
2146     case ARM::VST1d8Q:
2147     case ARM::VST1d16Q:
2148     case ARM::VST1d32Q:
2149     case ARM::VST1d64Q:
2150     case ARM::VST1d8Q_UPD:
2151     case ARM::VST1d16Q_UPD:
2152     case ARM::VST1d32Q_UPD:
2153     case ARM::VST1d64Q_UPD:
2154     case ARM::VST2q8:
2155     case ARM::VST2q16:
2156     case ARM::VST2q32:
2157     case ARM::VST2q8_UPD:
2158     case ARM::VST2q16_UPD:
2159     case ARM::VST2q32_UPD:
2160     case ARM::VST4d8:
2161     case ARM::VST4d16:
2162     case ARM::VST4d32:
2163     case ARM::VST4d8_UPD:
2164     case ARM::VST4d16_UPD:
2165     case ARM::VST4d32_UPD:
2166       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
2167         return MCDisassembler::Fail;
2168       break;
2169     case ARM::VST4q8:
2170     case ARM::VST4q16:
2171     case ARM::VST4q32:
2172     case ARM::VST4q8_UPD:
2173     case ARM::VST4q16_UPD:
2174     case ARM::VST4q32_UPD:
2175       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
2176         return MCDisassembler::Fail;
2177       break;
2178     default:
2179       break;
2180   }
2181 
2182   return S;
2183 }
2184 
2185 static DecodeStatus DecodeVLD1DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2186                                     uint64_t Address, const void *Decoder) {
2187   DecodeStatus S = MCDisassembler::Success;
2188 
2189   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2190   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2191   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2192   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2193   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2194   unsigned size = fieldFromInstruction32(Insn, 6, 2);
2195   unsigned regs = fieldFromInstruction32(Insn, 5, 1) + 1;
2196 
2197   align *= (1 << size);
2198 
2199   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2200     return MCDisassembler::Fail;
2201   if (regs == 2) {
2202     if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
2203       return MCDisassembler::Fail;
2204   }
2205   if (Rm != 0xF) {
2206     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2207       return MCDisassembler::Fail;
2208   }
2209 
2210   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2211     return MCDisassembler::Fail;
2212   Inst.addOperand(MCOperand::CreateImm(align));
2213 
2214   if (Rm == 0xD)
2215     Inst.addOperand(MCOperand::CreateReg(0));
2216   else if (Rm != 0xF) {
2217     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2218       return MCDisassembler::Fail;
2219   }
2220 
2221   return S;
2222 }
2223 
2224 static DecodeStatus DecodeVLD2DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2225                                     uint64_t Address, const void *Decoder) {
2226   DecodeStatus S = MCDisassembler::Success;
2227 
2228   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2229   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2230   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2231   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2232   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2233   unsigned size = 1 << fieldFromInstruction32(Insn, 6, 2);
2234   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2235   align *= 2*size;
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 (Rm != 0xF) {
2242     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2243       return MCDisassembler::Fail;
2244   }
2245 
2246   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2247     return MCDisassembler::Fail;
2248   Inst.addOperand(MCOperand::CreateImm(align));
2249 
2250   if (Rm == 0xD)
2251     Inst.addOperand(MCOperand::CreateReg(0));
2252   else if (Rm != 0xF) {
2253     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2254       return MCDisassembler::Fail;
2255   }
2256 
2257   return S;
2258 }
2259 
2260 static DecodeStatus DecodeVLD3DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2261                                     uint64_t Address, const void *Decoder) {
2262   DecodeStatus S = MCDisassembler::Success;
2263 
2264   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2265   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2266   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2267   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2268   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2269 
2270   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2271     return MCDisassembler::Fail;
2272   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
2273     return MCDisassembler::Fail;
2274   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
2275     return MCDisassembler::Fail;
2276   if (Rm != 0xF) {
2277     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2278       return MCDisassembler::Fail;
2279   }
2280 
2281   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2282     return MCDisassembler::Fail;
2283   Inst.addOperand(MCOperand::CreateImm(0));
2284 
2285   if (Rm == 0xD)
2286     Inst.addOperand(MCOperand::CreateReg(0));
2287   else if (Rm != 0xF) {
2288     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2289       return MCDisassembler::Fail;
2290   }
2291 
2292   return S;
2293 }
2294 
2295 static DecodeStatus DecodeVLD4DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2296                                     uint64_t Address, const void *Decoder) {
2297   DecodeStatus S = MCDisassembler::Success;
2298 
2299   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2300   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2301   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2302   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2303   unsigned size = fieldFromInstruction32(Insn, 6, 2);
2304   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2305   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2306 
2307   if (size == 0x3) {
2308     size = 4;
2309     align = 16;
2310   } else {
2311     if (size == 2) {
2312       size = 1 << size;
2313       align *= 8;
2314     } else {
2315       size = 1 << size;
2316       align *= 4*size;
2317     }
2318   }
2319 
2320   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2321     return MCDisassembler::Fail;
2322   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
2323     return MCDisassembler::Fail;
2324   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
2325     return MCDisassembler::Fail;
2326   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3*inc)%32, Address, Decoder)))
2327     return MCDisassembler::Fail;
2328   if (Rm != 0xF) {
2329     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2330       return MCDisassembler::Fail;
2331   }
2332 
2333   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2334     return MCDisassembler::Fail;
2335   Inst.addOperand(MCOperand::CreateImm(align));
2336 
2337   if (Rm == 0xD)
2338     Inst.addOperand(MCOperand::CreateReg(0));
2339   else if (Rm != 0xF) {
2340     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2341       return MCDisassembler::Fail;
2342   }
2343 
2344   return S;
2345 }
2346 
2347 static DecodeStatus
2348 DecodeNEONModImmInstruction(llvm::MCInst &Inst, unsigned Insn,
2349                             uint64_t Address, const void *Decoder) {
2350   DecodeStatus S = MCDisassembler::Success;
2351 
2352   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2353   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2354   unsigned imm = fieldFromInstruction32(Insn, 0, 4);
2355   imm |= fieldFromInstruction32(Insn, 16, 3) << 4;
2356   imm |= fieldFromInstruction32(Insn, 24, 1) << 7;
2357   imm |= fieldFromInstruction32(Insn, 8, 4) << 8;
2358   imm |= fieldFromInstruction32(Insn, 5, 1) << 12;
2359   unsigned Q = fieldFromInstruction32(Insn, 6, 1);
2360 
2361   if (Q) {
2362     if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2363     return MCDisassembler::Fail;
2364   } else {
2365     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2366     return MCDisassembler::Fail;
2367   }
2368 
2369   Inst.addOperand(MCOperand::CreateImm(imm));
2370 
2371   switch (Inst.getOpcode()) {
2372     case ARM::VORRiv4i16:
2373     case ARM::VORRiv2i32:
2374     case ARM::VBICiv4i16:
2375     case ARM::VBICiv2i32:
2376       if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2377         return MCDisassembler::Fail;
2378       break;
2379     case ARM::VORRiv8i16:
2380     case ARM::VORRiv4i32:
2381     case ARM::VBICiv8i16:
2382     case ARM::VBICiv4i32:
2383       if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2384         return MCDisassembler::Fail;
2385       break;
2386     default:
2387       break;
2388   }
2389 
2390   return S;
2391 }
2392 
2393 static DecodeStatus DecodeVSHLMaxInstruction(llvm::MCInst &Inst, unsigned Insn,
2394                                         uint64_t Address, const void *Decoder) {
2395   DecodeStatus S = MCDisassembler::Success;
2396 
2397   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2398   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2399   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2400   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
2401   unsigned size = fieldFromInstruction32(Insn, 18, 2);
2402 
2403   if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2404     return MCDisassembler::Fail;
2405   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
2406     return MCDisassembler::Fail;
2407   Inst.addOperand(MCOperand::CreateImm(8 << size));
2408 
2409   return S;
2410 }
2411 
2412 static DecodeStatus DecodeShiftRight8Imm(llvm::MCInst &Inst, unsigned Val,
2413                                uint64_t Address, const void *Decoder) {
2414   Inst.addOperand(MCOperand::CreateImm(8 - Val));
2415   return MCDisassembler::Success;
2416 }
2417 
2418 static DecodeStatus DecodeShiftRight16Imm(llvm::MCInst &Inst, unsigned Val,
2419                                uint64_t Address, const void *Decoder) {
2420   Inst.addOperand(MCOperand::CreateImm(16 - Val));
2421   return MCDisassembler::Success;
2422 }
2423 
2424 static DecodeStatus DecodeShiftRight32Imm(llvm::MCInst &Inst, unsigned Val,
2425                                uint64_t Address, const void *Decoder) {
2426   Inst.addOperand(MCOperand::CreateImm(32 - Val));
2427   return MCDisassembler::Success;
2428 }
2429 
2430 static DecodeStatus DecodeShiftRight64Imm(llvm::MCInst &Inst, unsigned Val,
2431                                uint64_t Address, const void *Decoder) {
2432   Inst.addOperand(MCOperand::CreateImm(64 - Val));
2433   return MCDisassembler::Success;
2434 }
2435 
2436 static DecodeStatus DecodeTBLInstruction(llvm::MCInst &Inst, unsigned Insn,
2437                                uint64_t Address, const void *Decoder) {
2438   DecodeStatus S = MCDisassembler::Success;
2439 
2440   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2441   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2442   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2443   Rn |= fieldFromInstruction32(Insn, 7, 1) << 4;
2444   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2445   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
2446   unsigned op = fieldFromInstruction32(Insn, 6, 1);
2447   unsigned length = fieldFromInstruction32(Insn, 8, 2) + 1;
2448 
2449   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2450     return MCDisassembler::Fail;
2451   if (op) {
2452     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2453     return MCDisassembler::Fail; // Writeback
2454   }
2455 
2456   for (unsigned i = 0; i < length; ++i) {
2457     if (!Check(S, DecodeDPRRegisterClass(Inst, (Rn+i)%32, Address, Decoder)))
2458     return MCDisassembler::Fail;
2459   }
2460 
2461   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
2462     return MCDisassembler::Fail;
2463 
2464   return S;
2465 }
2466 
2467 static DecodeStatus DecodeVFPfpImm(llvm::MCInst &Inst, unsigned Val,
2468                             uint64_t Address, const void *Decoder) {
2469   // The immediate needs to be a fully instantiated float.  However, the
2470   // auto-generated decoder is only able to fill in some of the bits
2471   // necessary.  For instance, the 'b' bit is replicated multiple times,
2472   // and is even present in inverted form in one bit.  We do a little
2473   // binary parsing here to fill in those missing bits, and then
2474   // reinterpret it all as a float.
2475   union {
2476     uint32_t integer;
2477     float fp;
2478   } fp_conv;
2479 
2480   fp_conv.integer = Val;
2481   uint32_t b = fieldFromInstruction32(Val, 25, 1);
2482   fp_conv.integer |= b << 26;
2483   fp_conv.integer |= b << 27;
2484   fp_conv.integer |= b << 28;
2485   fp_conv.integer |= b << 29;
2486   fp_conv.integer |= (~b & 0x1) << 30;
2487 
2488   Inst.addOperand(MCOperand::CreateFPImm(fp_conv.fp));
2489   return MCDisassembler::Success;
2490 }
2491 
2492 static DecodeStatus DecodeThumbAddSpecialReg(llvm::MCInst &Inst, uint16_t Insn,
2493                                      uint64_t Address, const void *Decoder) {
2494   DecodeStatus S = MCDisassembler::Success;
2495 
2496   unsigned dst = fieldFromInstruction16(Insn, 8, 3);
2497   unsigned imm = fieldFromInstruction16(Insn, 0, 8);
2498 
2499   if (!Check(S, DecodetGPRRegisterClass(Inst, dst, Address, Decoder)))
2500     return MCDisassembler::Fail;
2501 
2502   switch(Inst.getOpcode()) {
2503     default:
2504       return MCDisassembler::Fail;
2505     case ARM::tADR:
2506       break; // tADR does not explicitly represent the PC as an operand.
2507     case ARM::tADDrSPi:
2508       Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2509       break;
2510   }
2511 
2512   Inst.addOperand(MCOperand::CreateImm(imm));
2513   return S;
2514 }
2515 
2516 static DecodeStatus DecodeThumbBROperand(llvm::MCInst &Inst, unsigned Val,
2517                                  uint64_t Address, const void *Decoder) {
2518   Inst.addOperand(MCOperand::CreateImm(SignExtend32<12>(Val << 1)));
2519   return MCDisassembler::Success;
2520 }
2521 
2522 static DecodeStatus DecodeT2BROperand(llvm::MCInst &Inst, unsigned Val,
2523                                  uint64_t Address, const void *Decoder) {
2524   Inst.addOperand(MCOperand::CreateImm(SignExtend32<21>(Val)));
2525   return MCDisassembler::Success;
2526 }
2527 
2528 static DecodeStatus DecodeThumbCmpBROperand(llvm::MCInst &Inst, unsigned Val,
2529                                  uint64_t Address, const void *Decoder) {
2530   Inst.addOperand(MCOperand::CreateImm(SignExtend32<7>(Val << 1)));
2531   return MCDisassembler::Success;
2532 }
2533 
2534 static DecodeStatus DecodeThumbAddrModeRR(llvm::MCInst &Inst, unsigned Val,
2535                                  uint64_t Address, const void *Decoder) {
2536   DecodeStatus S = MCDisassembler::Success;
2537 
2538   unsigned Rn = fieldFromInstruction32(Val, 0, 3);
2539   unsigned Rm = fieldFromInstruction32(Val, 3, 3);
2540 
2541   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
2542     return MCDisassembler::Fail;
2543   if (!Check(S, DecodetGPRRegisterClass(Inst, Rm, Address, Decoder)))
2544     return MCDisassembler::Fail;
2545 
2546   return S;
2547 }
2548 
2549 static DecodeStatus DecodeThumbAddrModeIS(llvm::MCInst &Inst, unsigned Val,
2550                                   uint64_t Address, const void *Decoder) {
2551   DecodeStatus S = MCDisassembler::Success;
2552 
2553   unsigned Rn = fieldFromInstruction32(Val, 0, 3);
2554   unsigned imm = fieldFromInstruction32(Val, 3, 5);
2555 
2556   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
2557     return MCDisassembler::Fail;
2558   Inst.addOperand(MCOperand::CreateImm(imm));
2559 
2560   return S;
2561 }
2562 
2563 static DecodeStatus DecodeThumbAddrModePC(llvm::MCInst &Inst, unsigned Val,
2564                                   uint64_t Address, const void *Decoder) {
2565   Inst.addOperand(MCOperand::CreateImm(Val << 2));
2566 
2567   return MCDisassembler::Success;
2568 }
2569 
2570 static DecodeStatus DecodeThumbAddrModeSP(llvm::MCInst &Inst, unsigned Val,
2571                                   uint64_t Address, const void *Decoder) {
2572   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2573   Inst.addOperand(MCOperand::CreateImm(Val));
2574 
2575   return MCDisassembler::Success;
2576 }
2577 
2578 static DecodeStatus DecodeT2AddrModeSOReg(llvm::MCInst &Inst, unsigned Val,
2579                                   uint64_t Address, const void *Decoder) {
2580   DecodeStatus S = MCDisassembler::Success;
2581 
2582   unsigned Rn = fieldFromInstruction32(Val, 6, 4);
2583   unsigned Rm = fieldFromInstruction32(Val, 2, 4);
2584   unsigned imm = fieldFromInstruction32(Val, 0, 2);
2585 
2586   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2587     return MCDisassembler::Fail;
2588   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
2589     return MCDisassembler::Fail;
2590   Inst.addOperand(MCOperand::CreateImm(imm));
2591 
2592   return S;
2593 }
2594 
2595 static DecodeStatus DecodeT2LoadShift(llvm::MCInst &Inst, unsigned Insn,
2596                               uint64_t Address, const void *Decoder) {
2597   DecodeStatus S = MCDisassembler::Success;
2598 
2599   switch (Inst.getOpcode()) {
2600     case ARM::t2PLDs:
2601     case ARM::t2PLDWs:
2602     case ARM::t2PLIs:
2603       break;
2604     default: {
2605       unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2606       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
2607     return MCDisassembler::Fail;
2608     }
2609   }
2610 
2611   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2612   if (Rn == 0xF) {
2613     switch (Inst.getOpcode()) {
2614       case ARM::t2LDRBs:
2615         Inst.setOpcode(ARM::t2LDRBpci);
2616         break;
2617       case ARM::t2LDRHs:
2618         Inst.setOpcode(ARM::t2LDRHpci);
2619         break;
2620       case ARM::t2LDRSHs:
2621         Inst.setOpcode(ARM::t2LDRSHpci);
2622         break;
2623       case ARM::t2LDRSBs:
2624         Inst.setOpcode(ARM::t2LDRSBpci);
2625         break;
2626       case ARM::t2PLDs:
2627         Inst.setOpcode(ARM::t2PLDi12);
2628         Inst.addOperand(MCOperand::CreateReg(ARM::PC));
2629         break;
2630       default:
2631         return MCDisassembler::Fail;
2632     }
2633 
2634     int imm = fieldFromInstruction32(Insn, 0, 12);
2635     if (!fieldFromInstruction32(Insn, 23, 1)) imm *= -1;
2636     Inst.addOperand(MCOperand::CreateImm(imm));
2637 
2638     return S;
2639   }
2640 
2641   unsigned addrmode = fieldFromInstruction32(Insn, 4, 2);
2642   addrmode |= fieldFromInstruction32(Insn, 0, 4) << 2;
2643   addrmode |= fieldFromInstruction32(Insn, 16, 4) << 6;
2644   if (!Check(S, DecodeT2AddrModeSOReg(Inst, addrmode, Address, Decoder)))
2645     return MCDisassembler::Fail;
2646 
2647   return S;
2648 }
2649 
2650 static DecodeStatus DecodeT2Imm8S4(llvm::MCInst &Inst, unsigned Val,
2651                            uint64_t Address, const void *Decoder) {
2652   int imm = Val & 0xFF;
2653   if (!(Val & 0x100)) imm *= -1;
2654   Inst.addOperand(MCOperand::CreateImm(imm << 2));
2655 
2656   return MCDisassembler::Success;
2657 }
2658 
2659 static DecodeStatus DecodeT2AddrModeImm8s4(llvm::MCInst &Inst, unsigned Val,
2660                                    uint64_t Address, const void *Decoder) {
2661   DecodeStatus S = MCDisassembler::Success;
2662 
2663   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
2664   unsigned imm = fieldFromInstruction32(Val, 0, 9);
2665 
2666   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2667     return MCDisassembler::Fail;
2668   if (!Check(S, DecodeT2Imm8S4(Inst, imm, Address, Decoder)))
2669     return MCDisassembler::Fail;
2670 
2671   return S;
2672 }
2673 
2674 static DecodeStatus DecodeT2AddrModeImm0_1020s4(llvm::MCInst &Inst,unsigned Val,
2675                                    uint64_t Address, const void *Decoder) {
2676   DecodeStatus S = MCDisassembler::Success;
2677 
2678   unsigned Rn = fieldFromInstruction32(Val, 8, 4);
2679   unsigned imm = fieldFromInstruction32(Val, 0, 8);
2680 
2681   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
2682     return MCDisassembler::Fail;
2683 
2684   Inst.addOperand(MCOperand::CreateImm(imm));
2685 
2686   return S;
2687 }
2688 
2689 static DecodeStatus DecodeT2Imm8(llvm::MCInst &Inst, unsigned Val,
2690                          uint64_t Address, const void *Decoder) {
2691   int imm = Val & 0xFF;
2692   if (!(Val & 0x100)) imm *= -1;
2693   Inst.addOperand(MCOperand::CreateImm(imm));
2694 
2695   return MCDisassembler::Success;
2696 }
2697 
2698 
2699 static DecodeStatus DecodeT2AddrModeImm8(llvm::MCInst &Inst, unsigned Val,
2700                                  uint64_t Address, const void *Decoder) {
2701   DecodeStatus S = MCDisassembler::Success;
2702 
2703   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
2704   unsigned imm = fieldFromInstruction32(Val, 0, 9);
2705 
2706   // Some instructions always use an additive offset.
2707   switch (Inst.getOpcode()) {
2708     case ARM::t2LDRT:
2709     case ARM::t2LDRBT:
2710     case ARM::t2LDRHT:
2711     case ARM::t2LDRSBT:
2712     case ARM::t2LDRSHT:
2713       imm |= 0x100;
2714       break;
2715     default:
2716       break;
2717   }
2718 
2719   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2720     return MCDisassembler::Fail;
2721   if (!Check(S, DecodeT2Imm8(Inst, imm, Address, Decoder)))
2722     return MCDisassembler::Fail;
2723 
2724   return S;
2725 }
2726 
2727 
2728 static DecodeStatus DecodeT2AddrModeImm12(llvm::MCInst &Inst, unsigned Val,
2729                                   uint64_t Address, const void *Decoder) {
2730   DecodeStatus S = MCDisassembler::Success;
2731 
2732   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
2733   unsigned imm = fieldFromInstruction32(Val, 0, 12);
2734 
2735   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2736     return MCDisassembler::Fail;
2737   Inst.addOperand(MCOperand::CreateImm(imm));
2738 
2739   return S;
2740 }
2741 
2742 
2743 static DecodeStatus DecodeThumbAddSPImm(llvm::MCInst &Inst, uint16_t Insn,
2744                                 uint64_t Address, const void *Decoder) {
2745   unsigned imm = fieldFromInstruction16(Insn, 0, 7);
2746 
2747   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2748   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2749   Inst.addOperand(MCOperand::CreateImm(imm));
2750 
2751   return MCDisassembler::Success;
2752 }
2753 
2754 static DecodeStatus DecodeThumbAddSPReg(llvm::MCInst &Inst, uint16_t Insn,
2755                                 uint64_t Address, const void *Decoder) {
2756   DecodeStatus S = MCDisassembler::Success;
2757 
2758   if (Inst.getOpcode() == ARM::tADDrSP) {
2759     unsigned Rdm = fieldFromInstruction16(Insn, 0, 3);
2760     Rdm |= fieldFromInstruction16(Insn, 7, 1) << 3;
2761 
2762     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
2763     return MCDisassembler::Fail;
2764     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
2765     return MCDisassembler::Fail;
2766     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2767   } else if (Inst.getOpcode() == ARM::tADDspr) {
2768     unsigned Rm = fieldFromInstruction16(Insn, 3, 4);
2769 
2770     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2771     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2772     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2773     return MCDisassembler::Fail;
2774   }
2775 
2776   return S;
2777 }
2778 
2779 static DecodeStatus DecodeThumbCPS(llvm::MCInst &Inst, uint16_t Insn,
2780                            uint64_t Address, const void *Decoder) {
2781   unsigned imod = fieldFromInstruction16(Insn, 4, 1) | 0x2;
2782   unsigned flags = fieldFromInstruction16(Insn, 0, 3);
2783 
2784   Inst.addOperand(MCOperand::CreateImm(imod));
2785   Inst.addOperand(MCOperand::CreateImm(flags));
2786 
2787   return MCDisassembler::Success;
2788 }
2789 
2790 static DecodeStatus DecodePostIdxReg(llvm::MCInst &Inst, unsigned Insn,
2791                              uint64_t Address, const void *Decoder) {
2792   DecodeStatus S = MCDisassembler::Success;
2793   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2794   unsigned add = fieldFromInstruction32(Insn, 4, 1);
2795 
2796   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2797     return MCDisassembler::Fail;
2798   Inst.addOperand(MCOperand::CreateImm(add));
2799 
2800   return S;
2801 }
2802 
2803 static DecodeStatus DecodeThumbBLXOffset(llvm::MCInst &Inst, unsigned Val,
2804                                  uint64_t Address, const void *Decoder) {
2805   Inst.addOperand(MCOperand::CreateImm(SignExtend32<22>(Val << 1)));
2806   return MCDisassembler::Success;
2807 }
2808 
2809 static DecodeStatus DecodeCoprocessor(llvm::MCInst &Inst, unsigned Val,
2810                               uint64_t Address, const void *Decoder) {
2811   if (Val == 0xA || Val == 0xB)
2812     return MCDisassembler::Fail;
2813 
2814   Inst.addOperand(MCOperand::CreateImm(Val));
2815   return MCDisassembler::Success;
2816 }
2817 
2818 static DecodeStatus
2819 DecodeThumb2BCCInstruction(llvm::MCInst &Inst, unsigned Insn,
2820                            uint64_t Address, const void *Decoder) {
2821   DecodeStatus S = MCDisassembler::Success;
2822 
2823   unsigned pred = fieldFromInstruction32(Insn, 22, 4);
2824   if (pred == 0xE || pred == 0xF) {
2825     unsigned opc = fieldFromInstruction32(Insn, 4, 28);
2826     switch (opc) {
2827       default:
2828         return MCDisassembler::Fail;
2829       case 0xf3bf8f4:
2830         Inst.setOpcode(ARM::t2DSB);
2831         break;
2832       case 0xf3bf8f5:
2833         Inst.setOpcode(ARM::t2DMB);
2834         break;
2835       case 0xf3bf8f6:
2836         Inst.setOpcode(ARM::t2ISB);
2837         break;
2838     }
2839 
2840     unsigned imm = fieldFromInstruction32(Insn, 0, 4);
2841     return DecodeMemBarrierOption(Inst, imm, Address, Decoder);
2842   }
2843 
2844   unsigned brtarget = fieldFromInstruction32(Insn, 0, 11) << 1;
2845   brtarget |= fieldFromInstruction32(Insn, 11, 1) << 19;
2846   brtarget |= fieldFromInstruction32(Insn, 13, 1) << 18;
2847   brtarget |= fieldFromInstruction32(Insn, 16, 6) << 12;
2848   brtarget |= fieldFromInstruction32(Insn, 26, 1) << 20;
2849 
2850   if (!Check(S, DecodeT2BROperand(Inst, brtarget, Address, Decoder)))
2851     return MCDisassembler::Fail;
2852   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2853     return MCDisassembler::Fail;
2854 
2855   return S;
2856 }
2857 
2858 // Decode a shifted immediate operand.  These basically consist
2859 // of an 8-bit value, and a 4-bit directive that specifies either
2860 // a splat operation or a rotation.
2861 static DecodeStatus DecodeT2SOImm(llvm::MCInst &Inst, unsigned Val,
2862                           uint64_t Address, const void *Decoder) {
2863   unsigned ctrl = fieldFromInstruction32(Val, 10, 2);
2864   if (ctrl == 0) {
2865     unsigned byte = fieldFromInstruction32(Val, 8, 2);
2866     unsigned imm = fieldFromInstruction32(Val, 0, 8);
2867     switch (byte) {
2868       case 0:
2869         Inst.addOperand(MCOperand::CreateImm(imm));
2870         break;
2871       case 1:
2872         Inst.addOperand(MCOperand::CreateImm((imm << 16) | imm));
2873         break;
2874       case 2:
2875         Inst.addOperand(MCOperand::CreateImm((imm << 24) | (imm << 8)));
2876         break;
2877       case 3:
2878         Inst.addOperand(MCOperand::CreateImm((imm << 24) | (imm << 16) |
2879                                              (imm << 8)  |  imm));
2880         break;
2881     }
2882   } else {
2883     unsigned unrot = fieldFromInstruction32(Val, 0, 7) | 0x80;
2884     unsigned rot = fieldFromInstruction32(Val, 7, 5);
2885     unsigned imm = (unrot >> rot) | (unrot << ((32-rot)&31));
2886     Inst.addOperand(MCOperand::CreateImm(imm));
2887   }
2888 
2889   return MCDisassembler::Success;
2890 }
2891 
2892 static DecodeStatus
2893 DecodeThumbBCCTargetOperand(llvm::MCInst &Inst, unsigned Val,
2894                             uint64_t Address, const void *Decoder){
2895   Inst.addOperand(MCOperand::CreateImm(Val << 1));
2896   return MCDisassembler::Success;
2897 }
2898 
2899 static DecodeStatus DecodeThumbBLTargetOperand(llvm::MCInst &Inst, unsigned Val,
2900                                        uint64_t Address, const void *Decoder){
2901   Inst.addOperand(MCOperand::CreateImm(SignExtend32<22>(Val << 1)));
2902   return MCDisassembler::Success;
2903 }
2904 
2905 static DecodeStatus DecodeMemBarrierOption(llvm::MCInst &Inst, unsigned Val,
2906                                    uint64_t Address, const void *Decoder) {
2907   switch (Val) {
2908   default:
2909     return MCDisassembler::Fail;
2910   case 0xF: // SY
2911   case 0xE: // ST
2912   case 0xB: // ISH
2913   case 0xA: // ISHST
2914   case 0x7: // NSH
2915   case 0x6: // NSHST
2916   case 0x3: // OSH
2917   case 0x2: // OSHST
2918     break;
2919   }
2920 
2921   Inst.addOperand(MCOperand::CreateImm(Val));
2922   return MCDisassembler::Success;
2923 }
2924 
2925 static DecodeStatus DecodeMSRMask(llvm::MCInst &Inst, unsigned Val,
2926                           uint64_t Address, const void *Decoder) {
2927   if (!Val) return MCDisassembler::Fail;
2928   Inst.addOperand(MCOperand::CreateImm(Val));
2929   return MCDisassembler::Success;
2930 }
2931 
2932 static DecodeStatus DecodeDoubleRegLoad(llvm::MCInst &Inst, unsigned Insn,
2933                                         uint64_t Address, const void *Decoder) {
2934   DecodeStatus S = MCDisassembler::Success;
2935 
2936   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2937   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2938   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
2939 
2940   if ((Rt & 1) || Rt == 0xE || Rn == 0xF) return MCDisassembler::Fail;
2941 
2942   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
2943     return MCDisassembler::Fail;
2944   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
2945     return MCDisassembler::Fail;
2946   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2947     return MCDisassembler::Fail;
2948   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2949     return MCDisassembler::Fail;
2950 
2951   return S;
2952 }
2953 
2954 
2955 static DecodeStatus DecodeDoubleRegStore(llvm::MCInst &Inst, unsigned Insn,
2956                                          uint64_t Address, const void *Decoder){
2957   DecodeStatus S = MCDisassembler::Success;
2958 
2959   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2960   unsigned Rt = fieldFromInstruction32(Insn, 0, 4);
2961   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2962   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
2963 
2964   if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
2965     return MCDisassembler::Fail;
2966 
2967   if ((Rt & 1) || Rt == 0xE || Rn == 0xF) return MCDisassembler::Fail;
2968   if (Rd == Rn || Rd == Rt || Rd == Rt+1) return MCDisassembler::Fail;
2969 
2970   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
2971     return MCDisassembler::Fail;
2972   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
2973     return MCDisassembler::Fail;
2974   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2975     return MCDisassembler::Fail;
2976   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2977     return MCDisassembler::Fail;
2978 
2979   return S;
2980 }
2981 
2982 static DecodeStatus DecodeLDRPreImm(llvm::MCInst &Inst, unsigned Insn,
2983                             uint64_t Address, const void *Decoder) {
2984   DecodeStatus S = MCDisassembler::Success;
2985 
2986   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2987   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2988   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
2989   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
2990   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
2991   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
2992 
2993   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
2994 
2995   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
2996     return MCDisassembler::Fail;
2997   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2998     return MCDisassembler::Fail;
2999   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
3000     return MCDisassembler::Fail;
3001   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3002     return MCDisassembler::Fail;
3003 
3004   return S;
3005 }
3006 
3007 static DecodeStatus DecodeLDRPreReg(llvm::MCInst &Inst, unsigned Insn,
3008                             uint64_t Address, const void *Decoder) {
3009   DecodeStatus S = MCDisassembler::Success;
3010 
3011   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3012   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3013   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3014   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3015   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3016   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3017   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3018 
3019   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3020   if (Rm == 0xF) S = MCDisassembler::SoftFail;
3021 
3022   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3023     return MCDisassembler::Fail;
3024   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3025     return MCDisassembler::Fail;
3026   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
3027     return MCDisassembler::Fail;
3028   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3029     return MCDisassembler::Fail;
3030 
3031   return S;
3032 }
3033 
3034 
3035 static DecodeStatus DecodeSTRPreImm(llvm::MCInst &Inst, unsigned Insn,
3036                             uint64_t Address, const void *Decoder) {
3037   DecodeStatus S = MCDisassembler::Success;
3038 
3039   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3040   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3041   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3042   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3043   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3044   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3045 
3046   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3047 
3048   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3049     return MCDisassembler::Fail;
3050   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3051     return MCDisassembler::Fail;
3052   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
3053     return MCDisassembler::Fail;
3054   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3055     return MCDisassembler::Fail;
3056 
3057   return S;
3058 }
3059 
3060 static DecodeStatus DecodeSTRPreReg(llvm::MCInst &Inst, unsigned Insn,
3061                             uint64_t Address, const void *Decoder) {
3062   DecodeStatus S = MCDisassembler::Success;
3063 
3064   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3065   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3066   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3067   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3068   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3069   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3070 
3071   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3072 
3073   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3074     return MCDisassembler::Fail;
3075   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3076     return MCDisassembler::Fail;
3077   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
3078     return MCDisassembler::Fail;
3079   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3080     return MCDisassembler::Fail;
3081 
3082   return S;
3083 }
3084 
3085 static DecodeStatus DecodeVLD1LN(llvm::MCInst &Inst, unsigned Insn,
3086                          uint64_t Address, const void *Decoder) {
3087   DecodeStatus S = MCDisassembler::Success;
3088 
3089   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3090   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3091   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3092   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3093   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3094 
3095   unsigned align = 0;
3096   unsigned index = 0;
3097   switch (size) {
3098     default:
3099       return MCDisassembler::Fail;
3100     case 0:
3101       if (fieldFromInstruction32(Insn, 4, 1))
3102         return MCDisassembler::Fail; // UNDEFINED
3103       index = fieldFromInstruction32(Insn, 5, 3);
3104       break;
3105     case 1:
3106       if (fieldFromInstruction32(Insn, 5, 1))
3107         return MCDisassembler::Fail; // UNDEFINED
3108       index = fieldFromInstruction32(Insn, 6, 2);
3109       if (fieldFromInstruction32(Insn, 4, 1))
3110         align = 2;
3111       break;
3112     case 2:
3113       if (fieldFromInstruction32(Insn, 6, 1))
3114         return MCDisassembler::Fail; // UNDEFINED
3115       index = fieldFromInstruction32(Insn, 7, 1);
3116       if (fieldFromInstruction32(Insn, 4, 2) != 0)
3117         align = 4;
3118   }
3119 
3120   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3121     return MCDisassembler::Fail;
3122   if (Rm != 0xF) { // Writeback
3123     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3124       return MCDisassembler::Fail;
3125   }
3126   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3127     return MCDisassembler::Fail;
3128   Inst.addOperand(MCOperand::CreateImm(align));
3129   if (Rm != 0xF) {
3130     if (Rm != 0xD) {
3131       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3132         return MCDisassembler::Fail;
3133     } else
3134       Inst.addOperand(MCOperand::CreateReg(0));
3135   }
3136 
3137   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3138     return MCDisassembler::Fail;
3139   Inst.addOperand(MCOperand::CreateImm(index));
3140 
3141   return S;
3142 }
3143 
3144 static DecodeStatus DecodeVST1LN(llvm::MCInst &Inst, unsigned Insn,
3145                          uint64_t Address, const void *Decoder) {
3146   DecodeStatus S = MCDisassembler::Success;
3147 
3148   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3149   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3150   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3151   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3152   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3153 
3154   unsigned align = 0;
3155   unsigned index = 0;
3156   switch (size) {
3157     default:
3158       return MCDisassembler::Fail;
3159     case 0:
3160       if (fieldFromInstruction32(Insn, 4, 1))
3161         return MCDisassembler::Fail; // UNDEFINED
3162       index = fieldFromInstruction32(Insn, 5, 3);
3163       break;
3164     case 1:
3165       if (fieldFromInstruction32(Insn, 5, 1))
3166         return MCDisassembler::Fail; // UNDEFINED
3167       index = fieldFromInstruction32(Insn, 6, 2);
3168       if (fieldFromInstruction32(Insn, 4, 1))
3169         align = 2;
3170       break;
3171     case 2:
3172       if (fieldFromInstruction32(Insn, 6, 1))
3173         return MCDisassembler::Fail; // UNDEFINED
3174       index = fieldFromInstruction32(Insn, 7, 1);
3175       if (fieldFromInstruction32(Insn, 4, 2) != 0)
3176         align = 4;
3177   }
3178 
3179   if (Rm != 0xF) { // Writeback
3180     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3181     return MCDisassembler::Fail;
3182   }
3183   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3184     return MCDisassembler::Fail;
3185   Inst.addOperand(MCOperand::CreateImm(align));
3186   if (Rm != 0xF) {
3187     if (Rm != 0xD) {
3188       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3189     return MCDisassembler::Fail;
3190     } else
3191       Inst.addOperand(MCOperand::CreateReg(0));
3192   }
3193 
3194   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3195     return MCDisassembler::Fail;
3196   Inst.addOperand(MCOperand::CreateImm(index));
3197 
3198   return S;
3199 }
3200 
3201 
3202 static DecodeStatus DecodeVLD2LN(llvm::MCInst &Inst, unsigned Insn,
3203                          uint64_t Address, const void *Decoder) {
3204   DecodeStatus S = MCDisassembler::Success;
3205 
3206   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3207   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3208   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3209   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3210   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3211 
3212   unsigned align = 0;
3213   unsigned index = 0;
3214   unsigned inc = 1;
3215   switch (size) {
3216     default:
3217       return MCDisassembler::Fail;
3218     case 0:
3219       index = fieldFromInstruction32(Insn, 5, 3);
3220       if (fieldFromInstruction32(Insn, 4, 1))
3221         align = 2;
3222       break;
3223     case 1:
3224       index = fieldFromInstruction32(Insn, 6, 2);
3225       if (fieldFromInstruction32(Insn, 4, 1))
3226         align = 4;
3227       if (fieldFromInstruction32(Insn, 5, 1))
3228         inc = 2;
3229       break;
3230     case 2:
3231       if (fieldFromInstruction32(Insn, 5, 1))
3232         return MCDisassembler::Fail; // UNDEFINED
3233       index = fieldFromInstruction32(Insn, 7, 1);
3234       if (fieldFromInstruction32(Insn, 4, 1) != 0)
3235         align = 8;
3236       if (fieldFromInstruction32(Insn, 6, 1))
3237         inc = 2;
3238       break;
3239   }
3240 
3241   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3242     return MCDisassembler::Fail;
3243   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3244     return MCDisassembler::Fail;
3245   if (Rm != 0xF) { // Writeback
3246     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3247       return MCDisassembler::Fail;
3248   }
3249   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3250     return MCDisassembler::Fail;
3251   Inst.addOperand(MCOperand::CreateImm(align));
3252   if (Rm != 0xF) {
3253     if (Rm != 0xD) {
3254       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3255         return MCDisassembler::Fail;
3256     } else
3257       Inst.addOperand(MCOperand::CreateReg(0));
3258   }
3259 
3260   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3261     return MCDisassembler::Fail;
3262   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3263     return MCDisassembler::Fail;
3264   Inst.addOperand(MCOperand::CreateImm(index));
3265 
3266   return S;
3267 }
3268 
3269 static DecodeStatus DecodeVST2LN(llvm::MCInst &Inst, unsigned Insn,
3270                          uint64_t Address, const void *Decoder) {
3271   DecodeStatus S = MCDisassembler::Success;
3272 
3273   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3274   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3275   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3276   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3277   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3278 
3279   unsigned align = 0;
3280   unsigned index = 0;
3281   unsigned inc = 1;
3282   switch (size) {
3283     default:
3284       return MCDisassembler::Fail;
3285     case 0:
3286       index = fieldFromInstruction32(Insn, 5, 3);
3287       if (fieldFromInstruction32(Insn, 4, 1))
3288         align = 2;
3289       break;
3290     case 1:
3291       index = fieldFromInstruction32(Insn, 6, 2);
3292       if (fieldFromInstruction32(Insn, 4, 1))
3293         align = 4;
3294       if (fieldFromInstruction32(Insn, 5, 1))
3295         inc = 2;
3296       break;
3297     case 2:
3298       if (fieldFromInstruction32(Insn, 5, 1))
3299         return MCDisassembler::Fail; // UNDEFINED
3300       index = fieldFromInstruction32(Insn, 7, 1);
3301       if (fieldFromInstruction32(Insn, 4, 1) != 0)
3302         align = 8;
3303       if (fieldFromInstruction32(Insn, 6, 1))
3304         inc = 2;
3305       break;
3306   }
3307 
3308   if (Rm != 0xF) { // Writeback
3309     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3310       return MCDisassembler::Fail;
3311   }
3312   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3313     return MCDisassembler::Fail;
3314   Inst.addOperand(MCOperand::CreateImm(align));
3315   if (Rm != 0xF) {
3316     if (Rm != 0xD) {
3317       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3318         return MCDisassembler::Fail;
3319     } else
3320       Inst.addOperand(MCOperand::CreateReg(0));
3321   }
3322 
3323   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3324     return MCDisassembler::Fail;
3325   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3326     return MCDisassembler::Fail;
3327   Inst.addOperand(MCOperand::CreateImm(index));
3328 
3329   return S;
3330 }
3331 
3332 
3333 static DecodeStatus DecodeVLD3LN(llvm::MCInst &Inst, unsigned Insn,
3334                          uint64_t Address, const void *Decoder) {
3335   DecodeStatus S = MCDisassembler::Success;
3336 
3337   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3338   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3339   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3340   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3341   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3342 
3343   unsigned align = 0;
3344   unsigned index = 0;
3345   unsigned inc = 1;
3346   switch (size) {
3347     default:
3348       return MCDisassembler::Fail;
3349     case 0:
3350       if (fieldFromInstruction32(Insn, 4, 1))
3351         return MCDisassembler::Fail; // UNDEFINED
3352       index = fieldFromInstruction32(Insn, 5, 3);
3353       break;
3354     case 1:
3355       if (fieldFromInstruction32(Insn, 4, 1))
3356         return MCDisassembler::Fail; // UNDEFINED
3357       index = fieldFromInstruction32(Insn, 6, 2);
3358       if (fieldFromInstruction32(Insn, 5, 1))
3359         inc = 2;
3360       break;
3361     case 2:
3362       if (fieldFromInstruction32(Insn, 4, 2))
3363         return MCDisassembler::Fail; // UNDEFINED
3364       index = fieldFromInstruction32(Insn, 7, 1);
3365       if (fieldFromInstruction32(Insn, 6, 1))
3366         inc = 2;
3367       break;
3368   }
3369 
3370   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3371     return MCDisassembler::Fail;
3372   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3373     return MCDisassembler::Fail;
3374   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3375     return MCDisassembler::Fail;
3376 
3377   if (Rm != 0xF) { // Writeback
3378     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3379     return MCDisassembler::Fail;
3380   }
3381   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3382     return MCDisassembler::Fail;
3383   Inst.addOperand(MCOperand::CreateImm(align));
3384   if (Rm != 0xF) {
3385     if (Rm != 0xD) {
3386       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3387     return MCDisassembler::Fail;
3388     } else
3389       Inst.addOperand(MCOperand::CreateReg(0));
3390   }
3391 
3392   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3393     return MCDisassembler::Fail;
3394   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3395     return MCDisassembler::Fail;
3396   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3397     return MCDisassembler::Fail;
3398   Inst.addOperand(MCOperand::CreateImm(index));
3399 
3400   return S;
3401 }
3402 
3403 static DecodeStatus DecodeVST3LN(llvm::MCInst &Inst, unsigned Insn,
3404                          uint64_t Address, const void *Decoder) {
3405   DecodeStatus S = MCDisassembler::Success;
3406 
3407   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3408   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3409   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3410   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3411   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3412 
3413   unsigned align = 0;
3414   unsigned index = 0;
3415   unsigned inc = 1;
3416   switch (size) {
3417     default:
3418       return MCDisassembler::Fail;
3419     case 0:
3420       if (fieldFromInstruction32(Insn, 4, 1))
3421         return MCDisassembler::Fail; // UNDEFINED
3422       index = fieldFromInstruction32(Insn, 5, 3);
3423       break;
3424     case 1:
3425       if (fieldFromInstruction32(Insn, 4, 1))
3426         return MCDisassembler::Fail; // UNDEFINED
3427       index = fieldFromInstruction32(Insn, 6, 2);
3428       if (fieldFromInstruction32(Insn, 5, 1))
3429         inc = 2;
3430       break;
3431     case 2:
3432       if (fieldFromInstruction32(Insn, 4, 2))
3433         return MCDisassembler::Fail; // UNDEFINED
3434       index = fieldFromInstruction32(Insn, 7, 1);
3435       if (fieldFromInstruction32(Insn, 6, 1))
3436         inc = 2;
3437       break;
3438   }
3439 
3440   if (Rm != 0xF) { // Writeback
3441     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3442     return MCDisassembler::Fail;
3443   }
3444   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3445     return MCDisassembler::Fail;
3446   Inst.addOperand(MCOperand::CreateImm(align));
3447   if (Rm != 0xF) {
3448     if (Rm != 0xD) {
3449       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3450     return MCDisassembler::Fail;
3451     } else
3452       Inst.addOperand(MCOperand::CreateReg(0));
3453   }
3454 
3455   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3456     return MCDisassembler::Fail;
3457   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3458     return MCDisassembler::Fail;
3459   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3460     return MCDisassembler::Fail;
3461   Inst.addOperand(MCOperand::CreateImm(index));
3462 
3463   return S;
3464 }
3465 
3466 
3467 static DecodeStatus DecodeVLD4LN(llvm::MCInst &Inst, unsigned Insn,
3468                          uint64_t Address, const void *Decoder) {
3469   DecodeStatus S = MCDisassembler::Success;
3470 
3471   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3472   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3473   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3474   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3475   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3476 
3477   unsigned align = 0;
3478   unsigned index = 0;
3479   unsigned inc = 1;
3480   switch (size) {
3481     default:
3482       return MCDisassembler::Fail;
3483     case 0:
3484       if (fieldFromInstruction32(Insn, 4, 1))
3485         align = 4;
3486       index = fieldFromInstruction32(Insn, 5, 3);
3487       break;
3488     case 1:
3489       if (fieldFromInstruction32(Insn, 4, 1))
3490         align = 8;
3491       index = fieldFromInstruction32(Insn, 6, 2);
3492       if (fieldFromInstruction32(Insn, 5, 1))
3493         inc = 2;
3494       break;
3495     case 2:
3496       if (fieldFromInstruction32(Insn, 4, 2))
3497         align = 4 << fieldFromInstruction32(Insn, 4, 2);
3498       index = fieldFromInstruction32(Insn, 7, 1);
3499       if (fieldFromInstruction32(Insn, 6, 1))
3500         inc = 2;
3501       break;
3502   }
3503 
3504   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3505     return MCDisassembler::Fail;
3506   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3507     return MCDisassembler::Fail;
3508   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3509     return MCDisassembler::Fail;
3510   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
3511     return MCDisassembler::Fail;
3512 
3513   if (Rm != 0xF) { // Writeback
3514     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3515       return MCDisassembler::Fail;
3516   }
3517   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3518     return MCDisassembler::Fail;
3519   Inst.addOperand(MCOperand::CreateImm(align));
3520   if (Rm != 0xF) {
3521     if (Rm != 0xD) {
3522       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3523         return MCDisassembler::Fail;
3524     } else
3525       Inst.addOperand(MCOperand::CreateReg(0));
3526   }
3527 
3528   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3529     return MCDisassembler::Fail;
3530   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3531     return MCDisassembler::Fail;
3532   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3533     return MCDisassembler::Fail;
3534   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
3535     return MCDisassembler::Fail;
3536   Inst.addOperand(MCOperand::CreateImm(index));
3537 
3538   return S;
3539 }
3540 
3541 static DecodeStatus DecodeVST4LN(llvm::MCInst &Inst, unsigned Insn,
3542                          uint64_t Address, const void *Decoder) {
3543   DecodeStatus S = MCDisassembler::Success;
3544 
3545   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3546   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3547   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3548   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3549   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3550 
3551   unsigned align = 0;
3552   unsigned index = 0;
3553   unsigned inc = 1;
3554   switch (size) {
3555     default:
3556       return MCDisassembler::Fail;
3557     case 0:
3558       if (fieldFromInstruction32(Insn, 4, 1))
3559         align = 4;
3560       index = fieldFromInstruction32(Insn, 5, 3);
3561       break;
3562     case 1:
3563       if (fieldFromInstruction32(Insn, 4, 1))
3564         align = 8;
3565       index = fieldFromInstruction32(Insn, 6, 2);
3566       if (fieldFromInstruction32(Insn, 5, 1))
3567         inc = 2;
3568       break;
3569     case 2:
3570       if (fieldFromInstruction32(Insn, 4, 2))
3571         align = 4 << fieldFromInstruction32(Insn, 4, 2);
3572       index = fieldFromInstruction32(Insn, 7, 1);
3573       if (fieldFromInstruction32(Insn, 6, 1))
3574         inc = 2;
3575       break;
3576   }
3577 
3578   if (Rm != 0xF) { // Writeback
3579     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3580     return MCDisassembler::Fail;
3581   }
3582   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3583     return MCDisassembler::Fail;
3584   Inst.addOperand(MCOperand::CreateImm(align));
3585   if (Rm != 0xF) {
3586     if (Rm != 0xD) {
3587       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3588     return MCDisassembler::Fail;
3589     } else
3590       Inst.addOperand(MCOperand::CreateReg(0));
3591   }
3592 
3593   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3594     return MCDisassembler::Fail;
3595   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3596     return MCDisassembler::Fail;
3597   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3598     return MCDisassembler::Fail;
3599   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
3600     return MCDisassembler::Fail;
3601   Inst.addOperand(MCOperand::CreateImm(index));
3602 
3603   return S;
3604 }
3605 
3606 static DecodeStatus DecodeVMOVSRR(llvm::MCInst &Inst, unsigned Insn,
3607                                   uint64_t Address, const void *Decoder) {
3608   DecodeStatus S = MCDisassembler::Success;
3609   unsigned Rt  = fieldFromInstruction32(Insn, 12, 4);
3610   unsigned Rt2 = fieldFromInstruction32(Insn, 16, 4);
3611   unsigned Rm  = fieldFromInstruction32(Insn,  0, 4);
3612   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3613   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
3614 
3615   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
3616     S = MCDisassembler::SoftFail;
3617 
3618   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
3619     return MCDisassembler::Fail;
3620   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
3621     return MCDisassembler::Fail;
3622   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
3623     return MCDisassembler::Fail;
3624   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
3625     return MCDisassembler::Fail;
3626   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3627     return MCDisassembler::Fail;
3628 
3629   return S;
3630 }
3631 
3632 static DecodeStatus DecodeVMOVRRS(llvm::MCInst &Inst, unsigned Insn,
3633                                   uint64_t Address, const void *Decoder) {
3634   DecodeStatus S = MCDisassembler::Success;
3635   unsigned Rt  = fieldFromInstruction32(Insn, 12, 4);
3636   unsigned Rt2 = fieldFromInstruction32(Insn, 16, 4);
3637   unsigned Rm  = fieldFromInstruction32(Insn,  0, 4);
3638   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3639   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
3640 
3641   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
3642     S = MCDisassembler::SoftFail;
3643 
3644   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
3645     return MCDisassembler::Fail;
3646   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
3647     return MCDisassembler::Fail;
3648   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
3649     return MCDisassembler::Fail;
3650   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
3651     return MCDisassembler::Fail;
3652   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3653     return MCDisassembler::Fail;
3654 
3655   return S;
3656 }
3657 
3658 static DecodeStatus DecodeIT(llvm::MCInst &Inst, unsigned Insn,
3659                              uint64_t Address, const void *Decoder) {
3660   DecodeStatus S = MCDisassembler::Success;
3661   unsigned pred = fieldFromInstruction16(Insn, 4, 4);
3662   // The InstPrinter needs to have the low bit of the predicate in
3663   // the mask operand to be able to print it properly.
3664   unsigned mask = fieldFromInstruction16(Insn, 0, 5);
3665 
3666   if (pred == 0xF) {
3667     pred = 0xE;
3668     S = MCDisassembler::SoftFail;
3669   }
3670 
3671   if ((mask & 0xF) == 0) {
3672     // Preserve the high bit of the mask, which is the low bit of
3673     // the predicate.
3674     mask &= 0x10;
3675     mask |= 0x8;
3676     S = MCDisassembler::SoftFail;
3677   }
3678 
3679   Inst.addOperand(MCOperand::CreateImm(pred));
3680   Inst.addOperand(MCOperand::CreateImm(mask));
3681   return S;
3682 }
3683 
3684 static DecodeStatus
3685 DecodeT2LDRDPreInstruction(llvm::MCInst &Inst, unsigned Insn,
3686                            uint64_t Address, const void *Decoder) {
3687   DecodeStatus S = MCDisassembler::Success;
3688 
3689   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3690   unsigned Rt2 = fieldFromInstruction32(Insn, 8, 4);
3691   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3692   unsigned addr = fieldFromInstruction32(Insn, 0, 8);
3693   unsigned W = fieldFromInstruction32(Insn, 21, 1);
3694   unsigned U = fieldFromInstruction32(Insn, 23, 1);
3695   unsigned P = fieldFromInstruction32(Insn, 24, 1);
3696   bool writeback = (W == 1) | (P == 0);
3697 
3698   addr |= (U << 8) | (Rn << 9);
3699 
3700   if (writeback && (Rn == Rt || Rn == Rt2))
3701     Check(S, MCDisassembler::SoftFail);
3702   if (Rt == Rt2)
3703     Check(S, MCDisassembler::SoftFail);
3704 
3705   // Rt
3706   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
3707     return MCDisassembler::Fail;
3708   // Rt2
3709   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
3710     return MCDisassembler::Fail;
3711   // Writeback operand
3712   if (!Check(S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
3713     return MCDisassembler::Fail;
3714   // addr
3715   if (!Check(S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
3716     return MCDisassembler::Fail;
3717 
3718   return S;
3719 }
3720 
3721 static DecodeStatus
3722 DecodeT2STRDPreInstruction(llvm::MCInst &Inst, unsigned Insn,
3723                            uint64_t Address, const void *Decoder) {
3724   DecodeStatus S = MCDisassembler::Success;
3725 
3726   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3727   unsigned Rt2 = fieldFromInstruction32(Insn, 8, 4);
3728   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3729   unsigned addr = fieldFromInstruction32(Insn, 0, 8);
3730   unsigned W = fieldFromInstruction32(Insn, 21, 1);
3731   unsigned U = fieldFromInstruction32(Insn, 23, 1);
3732   unsigned P = fieldFromInstruction32(Insn, 24, 1);
3733   bool writeback = (W == 1) | (P == 0);
3734 
3735   addr |= (U << 8) | (Rn << 9);
3736 
3737   if (writeback && (Rn == Rt || Rn == Rt2))
3738     Check(S, MCDisassembler::SoftFail);
3739 
3740   // Writeback operand
3741   if (!Check(S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
3742     return MCDisassembler::Fail;
3743   // Rt
3744   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
3745     return MCDisassembler::Fail;
3746   // Rt2
3747   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
3748     return MCDisassembler::Fail;
3749   // addr
3750   if (!Check(S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
3751     return MCDisassembler::Fail;
3752 
3753   return S;
3754 }
3755