xref: /llvm-project/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp (revision 53db43b56050aecab831ae2ce98ded41b1f9dc7c)
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 static DecodeStatus DecodeT2Adr(llvm::MCInst &Inst, unsigned Val,
303                                 uint64_t Address, const void *Decoder);
304 
305 #include "ARMGenDisassemblerTables.inc"
306 #include "ARMGenInstrInfo.inc"
307 #include "ARMGenEDInfo.inc"
308 
309 static MCDisassembler *createARMDisassembler(const Target &T, const MCSubtargetInfo &STI) {
310   return new ARMDisassembler(STI);
311 }
312 
313 static MCDisassembler *createThumbDisassembler(const Target &T, const MCSubtargetInfo &STI) {
314   return new ThumbDisassembler(STI);
315 }
316 
317 EDInstInfo *ARMDisassembler::getEDInfo() const {
318   return instInfoARM;
319 }
320 
321 EDInstInfo *ThumbDisassembler::getEDInfo() const {
322   return instInfoARM;
323 }
324 
325 DecodeStatus ARMDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
326                                              const MemoryObject &Region,
327                                              uint64_t Address,
328                                              raw_ostream &os) const {
329   uint8_t bytes[4];
330 
331   assert(!(STI.getFeatureBits() & ARM::ModeThumb) &&
332          "Asked to disassemble an ARM instruction but Subtarget is in Thumb mode!");
333 
334   // We want to read exactly 4 bytes of data.
335   if (Region.readBytes(Address, 4, (uint8_t*)bytes, NULL) == -1) {
336     Size = 0;
337     return MCDisassembler::Fail;
338   }
339 
340   // Encoded as a small-endian 32-bit word in the stream.
341   uint32_t insn = (bytes[3] << 24) |
342                   (bytes[2] << 16) |
343                   (bytes[1] <<  8) |
344                   (bytes[0] <<  0);
345 
346   // Calling the auto-generated decoder function.
347   DecodeStatus result = decodeARMInstruction32(MI, insn, Address, this, STI);
348   if (result != MCDisassembler::Fail) {
349     Size = 4;
350     return result;
351   }
352 
353   // VFP and NEON instructions, similarly, are shared between ARM
354   // and Thumb modes.
355   MI.clear();
356   result = decodeVFPInstruction32(MI, insn, Address, this, STI);
357   if (result != MCDisassembler::Fail) {
358     Size = 4;
359     return result;
360   }
361 
362   MI.clear();
363   result = decodeNEONDataInstruction32(MI, insn, Address, this, STI);
364   if (result != MCDisassembler::Fail) {
365     Size = 4;
366     // Add a fake predicate operand, because we share these instruction
367     // definitions with Thumb2 where these instructions are predicable.
368     if (!DecodePredicateOperand(MI, 0xE, Address, this))
369       return MCDisassembler::Fail;
370     return result;
371   }
372 
373   MI.clear();
374   result = decodeNEONLoadStoreInstruction32(MI, insn, Address, this, STI);
375   if (result != MCDisassembler::Fail) {
376     Size = 4;
377     // Add a fake predicate operand, because we share these instruction
378     // definitions with Thumb2 where these instructions are predicable.
379     if (!DecodePredicateOperand(MI, 0xE, Address, this))
380       return MCDisassembler::Fail;
381     return result;
382   }
383 
384   MI.clear();
385   result = decodeNEONDupInstruction32(MI, insn, Address, this, STI);
386   if (result != MCDisassembler::Fail) {
387     Size = 4;
388     // Add a fake predicate operand, because we share these instruction
389     // definitions with Thumb2 where these instructions are predicable.
390     if (!DecodePredicateOperand(MI, 0xE, Address, this))
391       return MCDisassembler::Fail;
392     return result;
393   }
394 
395   MI.clear();
396 
397   Size = 0;
398   return MCDisassembler::Fail;
399 }
400 
401 namespace llvm {
402 extern MCInstrDesc ARMInsts[];
403 }
404 
405 // Thumb1 instructions don't have explicit S bits.  Rather, they
406 // implicitly set CPSR.  Since it's not represented in the encoding, the
407 // auto-generated decoder won't inject the CPSR operand.  We need to fix
408 // that as a post-pass.
409 static void AddThumb1SBit(MCInst &MI, bool InITBlock) {
410   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
411   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
412   MCInst::iterator I = MI.begin();
413   for (unsigned i = 0; i < NumOps; ++i, ++I) {
414     if (I == MI.end()) break;
415     if (OpInfo[i].isOptionalDef() && OpInfo[i].RegClass == ARM::CCRRegClassID) {
416       if (i > 0 && OpInfo[i-1].isPredicate()) continue;
417       MI.insert(I, MCOperand::CreateReg(InITBlock ? 0 : ARM::CPSR));
418       return;
419     }
420   }
421 
422   MI.insert(I, MCOperand::CreateReg(InITBlock ? 0 : ARM::CPSR));
423 }
424 
425 // Most Thumb instructions don't have explicit predicates in the
426 // encoding, but rather get their predicates from IT context.  We need
427 // to fix up the predicate operands using this context information as a
428 // post-pass.
429 MCDisassembler::DecodeStatus
430 ThumbDisassembler::AddThumbPredicate(MCInst &MI) const {
431   MCDisassembler::DecodeStatus S = Success;
432 
433   // A few instructions actually have predicates encoded in them.  Don't
434   // try to overwrite it if we're seeing one of those.
435   switch (MI.getOpcode()) {
436     case ARM::tBcc:
437     case ARM::t2Bcc:
438     case ARM::tCBZ:
439     case ARM::tCBNZ:
440       // Some instructions (mostly conditional branches) are not
441       // allowed in IT blocks.
442       if (!ITBlock.empty())
443         S = SoftFail;
444       else
445         return Success;
446       break;
447     case ARM::tB:
448     case ARM::t2B:
449       // Some instructions (mostly unconditional branches) can
450       // only appears at the end of, or outside of, an IT.
451       if (ITBlock.size() > 1)
452         S = SoftFail;
453       break;
454     default:
455       break;
456   }
457 
458   // If we're in an IT block, base the predicate on that.  Otherwise,
459   // assume a predicate of AL.
460   unsigned CC;
461   if (!ITBlock.empty()) {
462     CC = ITBlock.back();
463     if (CC == 0xF)
464       CC = ARMCC::AL;
465     ITBlock.pop_back();
466   } else
467     CC = ARMCC::AL;
468 
469   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
470   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
471   MCInst::iterator I = MI.begin();
472   for (unsigned i = 0; i < NumOps; ++i, ++I) {
473     if (I == MI.end()) break;
474     if (OpInfo[i].isPredicate()) {
475       I = MI.insert(I, MCOperand::CreateImm(CC));
476       ++I;
477       if (CC == ARMCC::AL)
478         MI.insert(I, MCOperand::CreateReg(0));
479       else
480         MI.insert(I, MCOperand::CreateReg(ARM::CPSR));
481       return S;
482     }
483   }
484 
485   I = MI.insert(I, MCOperand::CreateImm(CC));
486   ++I;
487   if (CC == ARMCC::AL)
488     MI.insert(I, MCOperand::CreateReg(0));
489   else
490     MI.insert(I, MCOperand::CreateReg(ARM::CPSR));
491 
492   return S;
493 }
494 
495 // Thumb VFP instructions are a special case.  Because we share their
496 // encodings between ARM and Thumb modes, and they are predicable in ARM
497 // mode, the auto-generated decoder will give them an (incorrect)
498 // predicate operand.  We need to rewrite these operands based on the IT
499 // context as a post-pass.
500 void ThumbDisassembler::UpdateThumbVFPPredicate(MCInst &MI) const {
501   unsigned CC;
502   if (!ITBlock.empty()) {
503     CC = ITBlock.back();
504     ITBlock.pop_back();
505   } else
506     CC = ARMCC::AL;
507 
508   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
509   MCInst::iterator I = MI.begin();
510   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
511   for (unsigned i = 0; i < NumOps; ++i, ++I) {
512     if (OpInfo[i].isPredicate() ) {
513       I->setImm(CC);
514       ++I;
515       if (CC == ARMCC::AL)
516         I->setReg(0);
517       else
518         I->setReg(ARM::CPSR);
519       return;
520     }
521   }
522 }
523 
524 DecodeStatus ThumbDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
525                                                const MemoryObject &Region,
526                                                uint64_t Address,
527                                                raw_ostream &os) const {
528   uint8_t bytes[4];
529 
530   assert((STI.getFeatureBits() & ARM::ModeThumb) &&
531          "Asked to disassemble in Thumb mode but Subtarget is in ARM mode!");
532 
533   // We want to read exactly 2 bytes of data.
534   if (Region.readBytes(Address, 2, (uint8_t*)bytes, NULL) == -1) {
535     Size = 0;
536     return MCDisassembler::Fail;
537   }
538 
539   uint16_t insn16 = (bytes[1] << 8) | bytes[0];
540   DecodeStatus result = decodeThumbInstruction16(MI, insn16, Address, this, STI);
541   if (result != MCDisassembler::Fail) {
542     Size = 2;
543     Check(result, AddThumbPredicate(MI));
544     return result;
545   }
546 
547   MI.clear();
548   result = decodeThumbSBitInstruction16(MI, insn16, Address, this, STI);
549   if (result) {
550     Size = 2;
551     bool InITBlock = !ITBlock.empty();
552     Check(result, AddThumbPredicate(MI));
553     AddThumb1SBit(MI, InITBlock);
554     return result;
555   }
556 
557   MI.clear();
558   result = decodeThumb2Instruction16(MI, insn16, Address, this, STI);
559   if (result != MCDisassembler::Fail) {
560     Size = 2;
561     Check(result, AddThumbPredicate(MI));
562 
563     // If we find an IT instruction, we need to parse its condition
564     // code and mask operands so that we can apply them correctly
565     // to the subsequent instructions.
566     if (MI.getOpcode() == ARM::t2IT) {
567       // (3 - the number of trailing zeros) is the number of then / else.
568       unsigned firstcond = MI.getOperand(0).getImm();
569       unsigned Mask = MI.getOperand(1).getImm();
570       unsigned CondBit0 = Mask >> 4 & 1;
571       unsigned NumTZ = CountTrailingZeros_32(Mask);
572       assert(NumTZ <= 3 && "Invalid IT mask!");
573       for (unsigned Pos = 3, e = NumTZ; Pos > e; --Pos) {
574         bool T = ((Mask >> Pos) & 1) == CondBit0;
575         if (T)
576           ITBlock.insert(ITBlock.begin(), firstcond);
577         else
578           ITBlock.insert(ITBlock.begin(), firstcond ^ 1);
579       }
580 
581       ITBlock.push_back(firstcond);
582     }
583 
584     return result;
585   }
586 
587   // We want to read exactly 4 bytes of data.
588   if (Region.readBytes(Address, 4, (uint8_t*)bytes, NULL) == -1) {
589     Size = 0;
590     return MCDisassembler::Fail;
591   }
592 
593   uint32_t insn32 = (bytes[3] <<  8) |
594                     (bytes[2] <<  0) |
595                     (bytes[1] << 24) |
596                     (bytes[0] << 16);
597   MI.clear();
598   result = decodeThumbInstruction32(MI, insn32, Address, this, STI);
599   if (result != MCDisassembler::Fail) {
600     Size = 4;
601     bool InITBlock = ITBlock.size();
602     Check(result, AddThumbPredicate(MI));
603     AddThumb1SBit(MI, InITBlock);
604     return result;
605   }
606 
607   MI.clear();
608   result = decodeThumb2Instruction32(MI, insn32, Address, this, STI);
609   if (result != MCDisassembler::Fail) {
610     Size = 4;
611     Check(result, AddThumbPredicate(MI));
612     return result;
613   }
614 
615   MI.clear();
616   result = decodeVFPInstruction32(MI, insn32, Address, this, STI);
617   if (result != MCDisassembler::Fail) {
618     Size = 4;
619     UpdateThumbVFPPredicate(MI);
620     return result;
621   }
622 
623   MI.clear();
624   result = decodeNEONDupInstruction32(MI, insn32, Address, this, STI);
625   if (result != MCDisassembler::Fail) {
626     Size = 4;
627     Check(result, AddThumbPredicate(MI));
628     return result;
629   }
630 
631   if (fieldFromInstruction32(insn32, 24, 8) == 0xF9) {
632     MI.clear();
633     uint32_t NEONLdStInsn = insn32;
634     NEONLdStInsn &= 0xF0FFFFFF;
635     NEONLdStInsn |= 0x04000000;
636     result = decodeNEONLoadStoreInstruction32(MI, NEONLdStInsn, Address, this, STI);
637     if (result != MCDisassembler::Fail) {
638       Size = 4;
639       Check(result, AddThumbPredicate(MI));
640       return result;
641     }
642   }
643 
644   if (fieldFromInstruction32(insn32, 24, 4) == 0xF) {
645     MI.clear();
646     uint32_t NEONDataInsn = insn32;
647     NEONDataInsn &= 0xF0FFFFFF; // Clear bits 27-24
648     NEONDataInsn |= (NEONDataInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
649     NEONDataInsn |= 0x12000000; // Set bits 28 and 25
650     result = decodeNEONDataInstruction32(MI, NEONDataInsn, Address, this, STI);
651     if (result != MCDisassembler::Fail) {
652       Size = 4;
653       Check(result, AddThumbPredicate(MI));
654       return result;
655     }
656   }
657 
658   Size = 0;
659   return MCDisassembler::Fail;
660 }
661 
662 
663 extern "C" void LLVMInitializeARMDisassembler() {
664   TargetRegistry::RegisterMCDisassembler(TheARMTarget,
665                                          createARMDisassembler);
666   TargetRegistry::RegisterMCDisassembler(TheThumbTarget,
667                                          createThumbDisassembler);
668 }
669 
670 static const unsigned GPRDecoderTable[] = {
671   ARM::R0, ARM::R1, ARM::R2, ARM::R3,
672   ARM::R4, ARM::R5, ARM::R6, ARM::R7,
673   ARM::R8, ARM::R9, ARM::R10, ARM::R11,
674   ARM::R12, ARM::SP, ARM::LR, ARM::PC
675 };
676 
677 static DecodeStatus DecodeGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
678                                    uint64_t Address, const void *Decoder) {
679   if (RegNo > 15)
680     return MCDisassembler::Fail;
681 
682   unsigned Register = GPRDecoderTable[RegNo];
683   Inst.addOperand(MCOperand::CreateReg(Register));
684   return MCDisassembler::Success;
685 }
686 
687 static DecodeStatus
688 DecodeGPRnopcRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
689                            uint64_t Address, const void *Decoder) {
690   if (RegNo == 15) return MCDisassembler::Fail;
691   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
692 }
693 
694 static DecodeStatus DecodetGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
695                                    uint64_t Address, const void *Decoder) {
696   if (RegNo > 7)
697     return MCDisassembler::Fail;
698   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
699 }
700 
701 static DecodeStatus DecodetcGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
702                                    uint64_t Address, const void *Decoder) {
703   unsigned Register = 0;
704   switch (RegNo) {
705     case 0:
706       Register = ARM::R0;
707       break;
708     case 1:
709       Register = ARM::R1;
710       break;
711     case 2:
712       Register = ARM::R2;
713       break;
714     case 3:
715       Register = ARM::R3;
716       break;
717     case 9:
718       Register = ARM::R9;
719       break;
720     case 12:
721       Register = ARM::R12;
722       break;
723     default:
724       return MCDisassembler::Fail;
725     }
726 
727   Inst.addOperand(MCOperand::CreateReg(Register));
728   return MCDisassembler::Success;
729 }
730 
731 static DecodeStatus DecoderGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
732                                    uint64_t Address, const void *Decoder) {
733   if (RegNo == 13 || RegNo == 15) return MCDisassembler::Fail;
734   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
735 }
736 
737 static const unsigned SPRDecoderTable[] = {
738      ARM::S0,  ARM::S1,  ARM::S2,  ARM::S3,
739      ARM::S4,  ARM::S5,  ARM::S6,  ARM::S7,
740      ARM::S8,  ARM::S9, ARM::S10, ARM::S11,
741     ARM::S12, ARM::S13, ARM::S14, ARM::S15,
742     ARM::S16, ARM::S17, ARM::S18, ARM::S19,
743     ARM::S20, ARM::S21, ARM::S22, ARM::S23,
744     ARM::S24, ARM::S25, ARM::S26, ARM::S27,
745     ARM::S28, ARM::S29, ARM::S30, ARM::S31
746 };
747 
748 static DecodeStatus DecodeSPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
749                                    uint64_t Address, const void *Decoder) {
750   if (RegNo > 31)
751     return MCDisassembler::Fail;
752 
753   unsigned Register = SPRDecoderTable[RegNo];
754   Inst.addOperand(MCOperand::CreateReg(Register));
755   return MCDisassembler::Success;
756 }
757 
758 static const unsigned DPRDecoderTable[] = {
759      ARM::D0,  ARM::D1,  ARM::D2,  ARM::D3,
760      ARM::D4,  ARM::D5,  ARM::D6,  ARM::D7,
761      ARM::D8,  ARM::D9, ARM::D10, ARM::D11,
762     ARM::D12, ARM::D13, ARM::D14, ARM::D15,
763     ARM::D16, ARM::D17, ARM::D18, ARM::D19,
764     ARM::D20, ARM::D21, ARM::D22, ARM::D23,
765     ARM::D24, ARM::D25, ARM::D26, ARM::D27,
766     ARM::D28, ARM::D29, ARM::D30, ARM::D31
767 };
768 
769 static DecodeStatus DecodeDPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
770                                    uint64_t Address, const void *Decoder) {
771   if (RegNo > 31)
772     return MCDisassembler::Fail;
773 
774   unsigned Register = DPRDecoderTable[RegNo];
775   Inst.addOperand(MCOperand::CreateReg(Register));
776   return MCDisassembler::Success;
777 }
778 
779 static DecodeStatus DecodeDPR_8RegisterClass(llvm::MCInst &Inst, unsigned RegNo,
780                                    uint64_t Address, const void *Decoder) {
781   if (RegNo > 7)
782     return MCDisassembler::Fail;
783   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
784 }
785 
786 static DecodeStatus
787 DecodeDPR_VFP2RegisterClass(llvm::MCInst &Inst, unsigned RegNo,
788                             uint64_t Address, const void *Decoder) {
789   if (RegNo > 15)
790     return MCDisassembler::Fail;
791   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
792 }
793 
794 static const unsigned QPRDecoderTable[] = {
795      ARM::Q0,  ARM::Q1,  ARM::Q2,  ARM::Q3,
796      ARM::Q4,  ARM::Q5,  ARM::Q6,  ARM::Q7,
797      ARM::Q8,  ARM::Q9, ARM::Q10, ARM::Q11,
798     ARM::Q12, ARM::Q13, ARM::Q14, ARM::Q15
799 };
800 
801 
802 static DecodeStatus DecodeQPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
803                                    uint64_t Address, const void *Decoder) {
804   if (RegNo > 31)
805     return MCDisassembler::Fail;
806   RegNo >>= 1;
807 
808   unsigned Register = QPRDecoderTable[RegNo];
809   Inst.addOperand(MCOperand::CreateReg(Register));
810   return MCDisassembler::Success;
811 }
812 
813 static DecodeStatus DecodePredicateOperand(llvm::MCInst &Inst, unsigned Val,
814                                uint64_t Address, const void *Decoder) {
815   if (Val == 0xF) return MCDisassembler::Fail;
816   // AL predicate is not allowed on Thumb1 branches.
817   if (Inst.getOpcode() == ARM::tBcc && Val == 0xE)
818     return MCDisassembler::Fail;
819   Inst.addOperand(MCOperand::CreateImm(Val));
820   if (Val == ARMCC::AL) {
821     Inst.addOperand(MCOperand::CreateReg(0));
822   } else
823     Inst.addOperand(MCOperand::CreateReg(ARM::CPSR));
824   return MCDisassembler::Success;
825 }
826 
827 static DecodeStatus DecodeCCOutOperand(llvm::MCInst &Inst, unsigned Val,
828                                uint64_t Address, const void *Decoder) {
829   if (Val)
830     Inst.addOperand(MCOperand::CreateReg(ARM::CPSR));
831   else
832     Inst.addOperand(MCOperand::CreateReg(0));
833   return MCDisassembler::Success;
834 }
835 
836 static DecodeStatus DecodeSOImmOperand(llvm::MCInst &Inst, unsigned Val,
837                                uint64_t Address, const void *Decoder) {
838   uint32_t imm = Val & 0xFF;
839   uint32_t rot = (Val & 0xF00) >> 7;
840   uint32_t rot_imm = (imm >> rot) | (imm << (32-rot));
841   Inst.addOperand(MCOperand::CreateImm(rot_imm));
842   return MCDisassembler::Success;
843 }
844 
845 static DecodeStatus DecodeSORegImmOperand(llvm::MCInst &Inst, unsigned Val,
846                                uint64_t Address, const void *Decoder) {
847   DecodeStatus S = MCDisassembler::Success;
848 
849   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
850   unsigned type = fieldFromInstruction32(Val, 5, 2);
851   unsigned imm = fieldFromInstruction32(Val, 7, 5);
852 
853   // Register-immediate
854   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
855     return MCDisassembler::Fail;
856 
857   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
858   switch (type) {
859     case 0:
860       Shift = ARM_AM::lsl;
861       break;
862     case 1:
863       Shift = ARM_AM::lsr;
864       break;
865     case 2:
866       Shift = ARM_AM::asr;
867       break;
868     case 3:
869       Shift = ARM_AM::ror;
870       break;
871   }
872 
873   if (Shift == ARM_AM::ror && imm == 0)
874     Shift = ARM_AM::rrx;
875 
876   unsigned Op = Shift | (imm << 3);
877   Inst.addOperand(MCOperand::CreateImm(Op));
878 
879   return S;
880 }
881 
882 static DecodeStatus DecodeSORegRegOperand(llvm::MCInst &Inst, unsigned Val,
883                                uint64_t Address, const void *Decoder) {
884   DecodeStatus S = MCDisassembler::Success;
885 
886   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
887   unsigned type = fieldFromInstruction32(Val, 5, 2);
888   unsigned Rs = fieldFromInstruction32(Val, 8, 4);
889 
890   // Register-register
891   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
892     return MCDisassembler::Fail;
893   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rs, Address, Decoder)))
894     return MCDisassembler::Fail;
895 
896   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
897   switch (type) {
898     case 0:
899       Shift = ARM_AM::lsl;
900       break;
901     case 1:
902       Shift = ARM_AM::lsr;
903       break;
904     case 2:
905       Shift = ARM_AM::asr;
906       break;
907     case 3:
908       Shift = ARM_AM::ror;
909       break;
910   }
911 
912   Inst.addOperand(MCOperand::CreateImm(Shift));
913 
914   return S;
915 }
916 
917 static DecodeStatus DecodeRegListOperand(llvm::MCInst &Inst, unsigned Val,
918                                  uint64_t Address, const void *Decoder) {
919   DecodeStatus S = MCDisassembler::Success;
920 
921   bool writebackLoad = false;
922   unsigned writebackReg = 0;
923   switch (Inst.getOpcode()) {
924     default:
925       break;
926     case ARM::LDMIA_UPD:
927     case ARM::LDMDB_UPD:
928     case ARM::LDMIB_UPD:
929     case ARM::LDMDA_UPD:
930     case ARM::t2LDMIA_UPD:
931     case ARM::t2LDMDB_UPD:
932       writebackLoad = true;
933       writebackReg = Inst.getOperand(0).getReg();
934       break;
935   }
936 
937   // Empty register lists are not allowed.
938   if (CountPopulation_32(Val) == 0) return MCDisassembler::Fail;
939   for (unsigned i = 0; i < 16; ++i) {
940     if (Val & (1 << i)) {
941       if (!Check(S, DecodeGPRRegisterClass(Inst, i, Address, Decoder)))
942         return MCDisassembler::Fail;
943       // Writeback not allowed if Rn is in the target list.
944       if (writebackLoad && writebackReg == Inst.end()[-1].getReg())
945         Check(S, MCDisassembler::SoftFail);
946     }
947   }
948 
949   return S;
950 }
951 
952 static DecodeStatus DecodeSPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
953                                  uint64_t Address, const void *Decoder) {
954   DecodeStatus S = MCDisassembler::Success;
955 
956   unsigned Vd = fieldFromInstruction32(Val, 8, 4);
957   unsigned regs = Val & 0xFF;
958 
959   if (!Check(S, DecodeSPRRegisterClass(Inst, Vd, Address, Decoder)))
960     return MCDisassembler::Fail;
961   for (unsigned i = 0; i < (regs - 1); ++i) {
962     if (!Check(S, DecodeSPRRegisterClass(Inst, ++Vd, Address, Decoder)))
963       return MCDisassembler::Fail;
964   }
965 
966   return S;
967 }
968 
969 static DecodeStatus DecodeDPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
970                                  uint64_t Address, const void *Decoder) {
971   DecodeStatus S = MCDisassembler::Success;
972 
973   unsigned Vd = fieldFromInstruction32(Val, 8, 4);
974   unsigned regs = (Val & 0xFF) / 2;
975 
976   if (!Check(S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)))
977       return MCDisassembler::Fail;
978   for (unsigned i = 0; i < (regs - 1); ++i) {
979     if (!Check(S, DecodeDPRRegisterClass(Inst, ++Vd, Address, Decoder)))
980       return MCDisassembler::Fail;
981   }
982 
983   return S;
984 }
985 
986 static DecodeStatus DecodeBitfieldMaskOperand(llvm::MCInst &Inst, unsigned Val,
987                                       uint64_t Address, const void *Decoder) {
988   // This operand encodes a mask of contiguous zeros between a specified MSB
989   // and LSB.  To decode it, we create the mask of all bits MSB-and-lower,
990   // the mask of all bits LSB-and-lower, and then xor them to create
991   // the mask of that's all ones on [msb, lsb].  Finally we not it to
992   // create the final mask.
993   unsigned msb = fieldFromInstruction32(Val, 5, 5);
994   unsigned lsb = fieldFromInstruction32(Val, 0, 5);
995   uint32_t msb_mask = (1 << (msb+1)) - 1;
996   uint32_t lsb_mask = (1 << lsb) - 1;
997   Inst.addOperand(MCOperand::CreateImm(~(msb_mask ^ lsb_mask)));
998   return MCDisassembler::Success;
999 }
1000 
1001 static DecodeStatus DecodeCopMemInstruction(llvm::MCInst &Inst, unsigned Insn,
1002                                   uint64_t Address, const void *Decoder) {
1003   DecodeStatus S = MCDisassembler::Success;
1004 
1005   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1006   unsigned CRd = fieldFromInstruction32(Insn, 12, 4);
1007   unsigned coproc = fieldFromInstruction32(Insn, 8, 4);
1008   unsigned imm = fieldFromInstruction32(Insn, 0, 8);
1009   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1010   unsigned U = fieldFromInstruction32(Insn, 23, 1);
1011 
1012   switch (Inst.getOpcode()) {
1013     case ARM::LDC_OFFSET:
1014     case ARM::LDC_PRE:
1015     case ARM::LDC_POST:
1016     case ARM::LDC_OPTION:
1017     case ARM::LDCL_OFFSET:
1018     case ARM::LDCL_PRE:
1019     case ARM::LDCL_POST:
1020     case ARM::LDCL_OPTION:
1021     case ARM::STC_OFFSET:
1022     case ARM::STC_PRE:
1023     case ARM::STC_POST:
1024     case ARM::STC_OPTION:
1025     case ARM::STCL_OFFSET:
1026     case ARM::STCL_PRE:
1027     case ARM::STCL_POST:
1028     case ARM::STCL_OPTION:
1029     case ARM::t2LDC_OFFSET:
1030     case ARM::t2LDC_PRE:
1031     case ARM::t2LDC_POST:
1032     case ARM::t2LDC_OPTION:
1033     case ARM::t2LDCL_OFFSET:
1034     case ARM::t2LDCL_PRE:
1035     case ARM::t2LDCL_POST:
1036     case ARM::t2LDCL_OPTION:
1037     case ARM::t2STC_OFFSET:
1038     case ARM::t2STC_PRE:
1039     case ARM::t2STC_POST:
1040     case ARM::t2STC_OPTION:
1041     case ARM::t2STCL_OFFSET:
1042     case ARM::t2STCL_PRE:
1043     case ARM::t2STCL_POST:
1044     case ARM::t2STCL_OPTION:
1045       if (coproc == 0xA || coproc == 0xB)
1046         return MCDisassembler::Fail;
1047       break;
1048     default:
1049       break;
1050   }
1051 
1052   Inst.addOperand(MCOperand::CreateImm(coproc));
1053   Inst.addOperand(MCOperand::CreateImm(CRd));
1054   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1055     return MCDisassembler::Fail;
1056   switch (Inst.getOpcode()) {
1057     case ARM::LDC_OPTION:
1058     case ARM::LDCL_OPTION:
1059     case ARM::LDC2_OPTION:
1060     case ARM::LDC2L_OPTION:
1061     case ARM::STC_OPTION:
1062     case ARM::STCL_OPTION:
1063     case ARM::STC2_OPTION:
1064     case ARM::STC2L_OPTION:
1065     case ARM::LDCL_POST:
1066     case ARM::STCL_POST:
1067     case ARM::LDC2L_POST:
1068     case ARM::STC2L_POST:
1069     case ARM::t2LDC_OPTION:
1070     case ARM::t2LDCL_OPTION:
1071     case ARM::t2STC_OPTION:
1072     case ARM::t2STCL_OPTION:
1073     case ARM::t2LDCL_POST:
1074     case ARM::t2STCL_POST:
1075       break;
1076     default:
1077       Inst.addOperand(MCOperand::CreateReg(0));
1078       break;
1079   }
1080 
1081   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1082   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1083 
1084   bool writeback = (P == 0) || (W == 1);
1085   unsigned idx_mode = 0;
1086   if (P && writeback)
1087     idx_mode = ARMII::IndexModePre;
1088   else if (!P && writeback)
1089     idx_mode = ARMII::IndexModePost;
1090 
1091   switch (Inst.getOpcode()) {
1092     case ARM::LDCL_POST:
1093     case ARM::STCL_POST:
1094     case ARM::t2LDCL_POST:
1095     case ARM::t2STCL_POST:
1096     case ARM::LDC2L_POST:
1097     case ARM::STC2L_POST:
1098       imm |= U << 8;
1099     case ARM::LDC_OPTION:
1100     case ARM::LDCL_OPTION:
1101     case ARM::LDC2_OPTION:
1102     case ARM::LDC2L_OPTION:
1103     case ARM::STC_OPTION:
1104     case ARM::STCL_OPTION:
1105     case ARM::STC2_OPTION:
1106     case ARM::STC2L_OPTION:
1107     case ARM::t2LDC_OPTION:
1108     case ARM::t2LDCL_OPTION:
1109     case ARM::t2STC_OPTION:
1110     case ARM::t2STCL_OPTION:
1111       Inst.addOperand(MCOperand::CreateImm(imm));
1112       break;
1113     default:
1114       if (U)
1115         Inst.addOperand(MCOperand::CreateImm(
1116             ARM_AM::getAM2Opc(ARM_AM::add, imm, ARM_AM::lsl, idx_mode)));
1117       else
1118         Inst.addOperand(MCOperand::CreateImm(
1119             ARM_AM::getAM2Opc(ARM_AM::sub, imm, ARM_AM::lsl, idx_mode)));
1120       break;
1121   }
1122 
1123   switch (Inst.getOpcode()) {
1124     case ARM::LDC_OFFSET:
1125     case ARM::LDC_PRE:
1126     case ARM::LDC_POST:
1127     case ARM::LDC_OPTION:
1128     case ARM::LDCL_OFFSET:
1129     case ARM::LDCL_PRE:
1130     case ARM::LDCL_POST:
1131     case ARM::LDCL_OPTION:
1132     case ARM::STC_OFFSET:
1133     case ARM::STC_PRE:
1134     case ARM::STC_POST:
1135     case ARM::STC_OPTION:
1136     case ARM::STCL_OFFSET:
1137     case ARM::STCL_PRE:
1138     case ARM::STCL_POST:
1139     case ARM::STCL_OPTION:
1140       if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1141         return MCDisassembler::Fail;
1142       break;
1143     default:
1144       break;
1145   }
1146 
1147   return S;
1148 }
1149 
1150 static DecodeStatus
1151 DecodeAddrMode2IdxInstruction(llvm::MCInst &Inst, unsigned Insn,
1152                               uint64_t Address, const void *Decoder) {
1153   DecodeStatus S = MCDisassembler::Success;
1154 
1155   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1156   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
1157   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1158   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
1159   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1160   unsigned reg = fieldFromInstruction32(Insn, 25, 1);
1161   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1162   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1163 
1164   // On stores, the writeback operand precedes Rt.
1165   switch (Inst.getOpcode()) {
1166     case ARM::STR_POST_IMM:
1167     case ARM::STR_POST_REG:
1168     case ARM::STRB_POST_IMM:
1169     case ARM::STRB_POST_REG:
1170     case ARM::STRT_POST_REG:
1171     case ARM::STRT_POST_IMM:
1172     case ARM::STRBT_POST_REG:
1173     case ARM::STRBT_POST_IMM:
1174       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1175         return MCDisassembler::Fail;
1176       break;
1177     default:
1178       break;
1179   }
1180 
1181   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
1182     return MCDisassembler::Fail;
1183 
1184   // On loads, the writeback operand comes after Rt.
1185   switch (Inst.getOpcode()) {
1186     case ARM::LDR_POST_IMM:
1187     case ARM::LDR_POST_REG:
1188     case ARM::LDRB_POST_IMM:
1189     case ARM::LDRB_POST_REG:
1190     case ARM::LDRBT_POST_REG:
1191     case ARM::LDRBT_POST_IMM:
1192     case ARM::LDRT_POST_REG:
1193     case ARM::LDRT_POST_IMM:
1194       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1195         return MCDisassembler::Fail;
1196       break;
1197     default:
1198       break;
1199   }
1200 
1201   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1202     return MCDisassembler::Fail;
1203 
1204   ARM_AM::AddrOpc Op = ARM_AM::add;
1205   if (!fieldFromInstruction32(Insn, 23, 1))
1206     Op = ARM_AM::sub;
1207 
1208   bool writeback = (P == 0) || (W == 1);
1209   unsigned idx_mode = 0;
1210   if (P && writeback)
1211     idx_mode = ARMII::IndexModePre;
1212   else if (!P && writeback)
1213     idx_mode = ARMII::IndexModePost;
1214 
1215   if (writeback && (Rn == 15 || Rn == Rt))
1216     S = MCDisassembler::SoftFail; // UNPREDICTABLE
1217 
1218   if (reg) {
1219     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1220       return MCDisassembler::Fail;
1221     ARM_AM::ShiftOpc Opc = ARM_AM::lsl;
1222     switch( fieldFromInstruction32(Insn, 5, 2)) {
1223       case 0:
1224         Opc = ARM_AM::lsl;
1225         break;
1226       case 1:
1227         Opc = ARM_AM::lsr;
1228         break;
1229       case 2:
1230         Opc = ARM_AM::asr;
1231         break;
1232       case 3:
1233         Opc = ARM_AM::ror;
1234         break;
1235       default:
1236         return MCDisassembler::Fail;
1237     }
1238     unsigned amt = fieldFromInstruction32(Insn, 7, 5);
1239     unsigned imm = ARM_AM::getAM2Opc(Op, amt, Opc, idx_mode);
1240 
1241     Inst.addOperand(MCOperand::CreateImm(imm));
1242   } else {
1243     Inst.addOperand(MCOperand::CreateReg(0));
1244     unsigned tmp = ARM_AM::getAM2Opc(Op, imm, ARM_AM::lsl, idx_mode);
1245     Inst.addOperand(MCOperand::CreateImm(tmp));
1246   }
1247 
1248   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1249     return MCDisassembler::Fail;
1250 
1251   return S;
1252 }
1253 
1254 static DecodeStatus DecodeSORegMemOperand(llvm::MCInst &Inst, unsigned Val,
1255                                   uint64_t Address, const void *Decoder) {
1256   DecodeStatus S = MCDisassembler::Success;
1257 
1258   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
1259   unsigned Rm = fieldFromInstruction32(Val,  0, 4);
1260   unsigned type = fieldFromInstruction32(Val, 5, 2);
1261   unsigned imm = fieldFromInstruction32(Val, 7, 5);
1262   unsigned U = fieldFromInstruction32(Val, 12, 1);
1263 
1264   ARM_AM::ShiftOpc ShOp = ARM_AM::lsl;
1265   switch (type) {
1266     case 0:
1267       ShOp = ARM_AM::lsl;
1268       break;
1269     case 1:
1270       ShOp = ARM_AM::lsr;
1271       break;
1272     case 2:
1273       ShOp = ARM_AM::asr;
1274       break;
1275     case 3:
1276       ShOp = ARM_AM::ror;
1277       break;
1278   }
1279 
1280   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1281     return MCDisassembler::Fail;
1282   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1283     return MCDisassembler::Fail;
1284   unsigned shift;
1285   if (U)
1286     shift = ARM_AM::getAM2Opc(ARM_AM::add, imm, ShOp);
1287   else
1288     shift = ARM_AM::getAM2Opc(ARM_AM::sub, imm, ShOp);
1289   Inst.addOperand(MCOperand::CreateImm(shift));
1290 
1291   return S;
1292 }
1293 
1294 static DecodeStatus
1295 DecodeAddrMode3Instruction(llvm::MCInst &Inst, unsigned Insn,
1296                            uint64_t Address, const void *Decoder) {
1297   DecodeStatus S = MCDisassembler::Success;
1298 
1299   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
1300   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1301   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1302   unsigned type = fieldFromInstruction32(Insn, 22, 1);
1303   unsigned imm = fieldFromInstruction32(Insn, 8, 4);
1304   unsigned U = ((~fieldFromInstruction32(Insn, 23, 1)) & 1) << 8;
1305   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1306   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1307   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1308 
1309   bool writeback = (W == 1) | (P == 0);
1310 
1311   // For {LD,ST}RD, Rt must be even, else undefined.
1312   switch (Inst.getOpcode()) {
1313     case ARM::STRD:
1314     case ARM::STRD_PRE:
1315     case ARM::STRD_POST:
1316     case ARM::LDRD:
1317     case ARM::LDRD_PRE:
1318     case ARM::LDRD_POST:
1319       if (Rt & 0x1) return MCDisassembler::Fail;
1320       break;
1321     default:
1322       break;
1323   }
1324 
1325   if (writeback) { // Writeback
1326     if (P)
1327       U |= ARMII::IndexModePre << 9;
1328     else
1329       U |= ARMII::IndexModePost << 9;
1330 
1331     // On stores, the writeback operand precedes Rt.
1332     switch (Inst.getOpcode()) {
1333     case ARM::STRD:
1334     case ARM::STRD_PRE:
1335     case ARM::STRD_POST:
1336     case ARM::STRH:
1337     case ARM::STRH_PRE:
1338     case ARM::STRH_POST:
1339       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1340         return MCDisassembler::Fail;
1341       break;
1342     default:
1343       break;
1344     }
1345   }
1346 
1347   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
1348     return MCDisassembler::Fail;
1349   switch (Inst.getOpcode()) {
1350     case ARM::STRD:
1351     case ARM::STRD_PRE:
1352     case ARM::STRD_POST:
1353     case ARM::LDRD:
1354     case ARM::LDRD_PRE:
1355     case ARM::LDRD_POST:
1356       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
1357         return MCDisassembler::Fail;
1358       break;
1359     default:
1360       break;
1361   }
1362 
1363   if (writeback) {
1364     // On loads, the writeback operand comes after Rt.
1365     switch (Inst.getOpcode()) {
1366     case ARM::LDRD:
1367     case ARM::LDRD_PRE:
1368     case ARM::LDRD_POST:
1369     case ARM::LDRH:
1370     case ARM::LDRH_PRE:
1371     case ARM::LDRH_POST:
1372     case ARM::LDRSH:
1373     case ARM::LDRSH_PRE:
1374     case ARM::LDRSH_POST:
1375     case ARM::LDRSB:
1376     case ARM::LDRSB_PRE:
1377     case ARM::LDRSB_POST:
1378     case ARM::LDRHTr:
1379     case ARM::LDRSBTr:
1380       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1381         return MCDisassembler::Fail;
1382       break;
1383     default:
1384       break;
1385     }
1386   }
1387 
1388   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1389     return MCDisassembler::Fail;
1390 
1391   if (type) {
1392     Inst.addOperand(MCOperand::CreateReg(0));
1393     Inst.addOperand(MCOperand::CreateImm(U | (imm << 4) | Rm));
1394   } else {
1395     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1396     return MCDisassembler::Fail;
1397     Inst.addOperand(MCOperand::CreateImm(U));
1398   }
1399 
1400   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1401     return MCDisassembler::Fail;
1402 
1403   return S;
1404 }
1405 
1406 static DecodeStatus DecodeRFEInstruction(llvm::MCInst &Inst, unsigned Insn,
1407                                  uint64_t Address, const void *Decoder) {
1408   DecodeStatus S = MCDisassembler::Success;
1409 
1410   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1411   unsigned mode = fieldFromInstruction32(Insn, 23, 2);
1412 
1413   switch (mode) {
1414     case 0:
1415       mode = ARM_AM::da;
1416       break;
1417     case 1:
1418       mode = ARM_AM::ia;
1419       break;
1420     case 2:
1421       mode = ARM_AM::db;
1422       break;
1423     case 3:
1424       mode = ARM_AM::ib;
1425       break;
1426   }
1427 
1428   Inst.addOperand(MCOperand::CreateImm(mode));
1429   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1430     return MCDisassembler::Fail;
1431 
1432   return S;
1433 }
1434 
1435 static DecodeStatus DecodeMemMultipleWritebackInstruction(llvm::MCInst &Inst,
1436                                   unsigned Insn,
1437                                   uint64_t Address, const void *Decoder) {
1438   DecodeStatus S = MCDisassembler::Success;
1439 
1440   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1441   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1442   unsigned reglist = fieldFromInstruction32(Insn, 0, 16);
1443 
1444   if (pred == 0xF) {
1445     switch (Inst.getOpcode()) {
1446       case ARM::LDMDA:
1447         Inst.setOpcode(ARM::RFEDA);
1448         break;
1449       case ARM::LDMDA_UPD:
1450         Inst.setOpcode(ARM::RFEDA_UPD);
1451         break;
1452       case ARM::LDMDB:
1453         Inst.setOpcode(ARM::RFEDB);
1454         break;
1455       case ARM::LDMDB_UPD:
1456         Inst.setOpcode(ARM::RFEDB_UPD);
1457         break;
1458       case ARM::LDMIA:
1459         Inst.setOpcode(ARM::RFEIA);
1460         break;
1461       case ARM::LDMIA_UPD:
1462         Inst.setOpcode(ARM::RFEIA_UPD);
1463         break;
1464       case ARM::LDMIB:
1465         Inst.setOpcode(ARM::RFEIB);
1466         break;
1467       case ARM::LDMIB_UPD:
1468         Inst.setOpcode(ARM::RFEIB_UPD);
1469         break;
1470       case ARM::STMDA:
1471         Inst.setOpcode(ARM::SRSDA);
1472         break;
1473       case ARM::STMDA_UPD:
1474         Inst.setOpcode(ARM::SRSDA_UPD);
1475         break;
1476       case ARM::STMDB:
1477         Inst.setOpcode(ARM::SRSDB);
1478         break;
1479       case ARM::STMDB_UPD:
1480         Inst.setOpcode(ARM::SRSDB_UPD);
1481         break;
1482       case ARM::STMIA:
1483         Inst.setOpcode(ARM::SRSIA);
1484         break;
1485       case ARM::STMIA_UPD:
1486         Inst.setOpcode(ARM::SRSIA_UPD);
1487         break;
1488       case ARM::STMIB:
1489         Inst.setOpcode(ARM::SRSIB);
1490         break;
1491       case ARM::STMIB_UPD:
1492         Inst.setOpcode(ARM::SRSIB_UPD);
1493         break;
1494       default:
1495         if (!Check(S, MCDisassembler::Fail)) return MCDisassembler::Fail;
1496     }
1497 
1498     // For stores (which become SRS's, the only operand is the mode.
1499     if (fieldFromInstruction32(Insn, 20, 1) == 0) {
1500       Inst.addOperand(
1501           MCOperand::CreateImm(fieldFromInstruction32(Insn, 0, 4)));
1502       return S;
1503     }
1504 
1505     return DecodeRFEInstruction(Inst, Insn, Address, Decoder);
1506   }
1507 
1508   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1509     return MCDisassembler::Fail;
1510   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1511     return MCDisassembler::Fail; // Tied
1512   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1513     return MCDisassembler::Fail;
1514   if (!Check(S, DecodeRegListOperand(Inst, reglist, Address, Decoder)))
1515     return MCDisassembler::Fail;
1516 
1517   return S;
1518 }
1519 
1520 static DecodeStatus DecodeCPSInstruction(llvm::MCInst &Inst, unsigned Insn,
1521                                  uint64_t Address, const void *Decoder) {
1522   unsigned imod = fieldFromInstruction32(Insn, 18, 2);
1523   unsigned M = fieldFromInstruction32(Insn, 17, 1);
1524   unsigned iflags = fieldFromInstruction32(Insn, 6, 3);
1525   unsigned mode = fieldFromInstruction32(Insn, 0, 5);
1526 
1527   DecodeStatus S = MCDisassembler::Success;
1528 
1529   // imod == '01' --> UNPREDICTABLE
1530   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
1531   // return failure here.  The '01' imod value is unprintable, so there's
1532   // nothing useful we could do even if we returned UNPREDICTABLE.
1533 
1534   if (imod == 1) return MCDisassembler::Fail;
1535 
1536   if (imod && M) {
1537     Inst.setOpcode(ARM::CPS3p);
1538     Inst.addOperand(MCOperand::CreateImm(imod));
1539     Inst.addOperand(MCOperand::CreateImm(iflags));
1540     Inst.addOperand(MCOperand::CreateImm(mode));
1541   } else if (imod && !M) {
1542     Inst.setOpcode(ARM::CPS2p);
1543     Inst.addOperand(MCOperand::CreateImm(imod));
1544     Inst.addOperand(MCOperand::CreateImm(iflags));
1545     if (mode) S = MCDisassembler::SoftFail;
1546   } else if (!imod && M) {
1547     Inst.setOpcode(ARM::CPS1p);
1548     Inst.addOperand(MCOperand::CreateImm(mode));
1549     if (iflags) S = MCDisassembler::SoftFail;
1550   } else {
1551     // imod == '00' && M == '0' --> UNPREDICTABLE
1552     Inst.setOpcode(ARM::CPS1p);
1553     Inst.addOperand(MCOperand::CreateImm(mode));
1554     S = MCDisassembler::SoftFail;
1555   }
1556 
1557   return S;
1558 }
1559 
1560 static DecodeStatus DecodeT2CPSInstruction(llvm::MCInst &Inst, unsigned Insn,
1561                                  uint64_t Address, const void *Decoder) {
1562   unsigned imod = fieldFromInstruction32(Insn, 9, 2);
1563   unsigned M = fieldFromInstruction32(Insn, 8, 1);
1564   unsigned iflags = fieldFromInstruction32(Insn, 5, 3);
1565   unsigned mode = fieldFromInstruction32(Insn, 0, 5);
1566 
1567   DecodeStatus S = MCDisassembler::Success;
1568 
1569   // imod == '01' --> UNPREDICTABLE
1570   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
1571   // return failure here.  The '01' imod value is unprintable, so there's
1572   // nothing useful we could do even if we returned UNPREDICTABLE.
1573 
1574   if (imod == 1) return MCDisassembler::Fail;
1575 
1576   if (imod && M) {
1577     Inst.setOpcode(ARM::t2CPS3p);
1578     Inst.addOperand(MCOperand::CreateImm(imod));
1579     Inst.addOperand(MCOperand::CreateImm(iflags));
1580     Inst.addOperand(MCOperand::CreateImm(mode));
1581   } else if (imod && !M) {
1582     Inst.setOpcode(ARM::t2CPS2p);
1583     Inst.addOperand(MCOperand::CreateImm(imod));
1584     Inst.addOperand(MCOperand::CreateImm(iflags));
1585     if (mode) S = MCDisassembler::SoftFail;
1586   } else if (!imod && M) {
1587     Inst.setOpcode(ARM::t2CPS1p);
1588     Inst.addOperand(MCOperand::CreateImm(mode));
1589     if (iflags) S = MCDisassembler::SoftFail;
1590   } else {
1591     // imod == '00' && M == '0' --> UNPREDICTABLE
1592     Inst.setOpcode(ARM::t2CPS1p);
1593     Inst.addOperand(MCOperand::CreateImm(mode));
1594     S = MCDisassembler::SoftFail;
1595   }
1596 
1597   return S;
1598 }
1599 
1600 
1601 static DecodeStatus DecodeSMLAInstruction(llvm::MCInst &Inst, unsigned Insn,
1602                                  uint64_t Address, const void *Decoder) {
1603   DecodeStatus S = MCDisassembler::Success;
1604 
1605   unsigned Rd = fieldFromInstruction32(Insn, 16, 4);
1606   unsigned Rn = fieldFromInstruction32(Insn, 0, 4);
1607   unsigned Rm = fieldFromInstruction32(Insn, 8, 4);
1608   unsigned Ra = fieldFromInstruction32(Insn, 12, 4);
1609   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1610 
1611   if (pred == 0xF)
1612     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
1613 
1614   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
1615     return MCDisassembler::Fail;
1616   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
1617     return MCDisassembler::Fail;
1618   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1619     return MCDisassembler::Fail;
1620   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Ra, Address, Decoder)))
1621     return MCDisassembler::Fail;
1622 
1623   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1624     return MCDisassembler::Fail;
1625 
1626   return S;
1627 }
1628 
1629 static DecodeStatus DecodeAddrModeImm12Operand(llvm::MCInst &Inst, unsigned Val,
1630                            uint64_t Address, const void *Decoder) {
1631   DecodeStatus S = MCDisassembler::Success;
1632 
1633   unsigned add = fieldFromInstruction32(Val, 12, 1);
1634   unsigned imm = fieldFromInstruction32(Val, 0, 12);
1635   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
1636 
1637   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1638     return MCDisassembler::Fail;
1639 
1640   if (!add) imm *= -1;
1641   if (imm == 0 && !add) imm = INT32_MIN;
1642   Inst.addOperand(MCOperand::CreateImm(imm));
1643 
1644   return S;
1645 }
1646 
1647 static DecodeStatus DecodeAddrMode5Operand(llvm::MCInst &Inst, unsigned Val,
1648                                    uint64_t Address, const void *Decoder) {
1649   DecodeStatus S = MCDisassembler::Success;
1650 
1651   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
1652   unsigned U = fieldFromInstruction32(Val, 8, 1);
1653   unsigned imm = fieldFromInstruction32(Val, 0, 8);
1654 
1655   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1656     return MCDisassembler::Fail;
1657 
1658   if (U)
1659     Inst.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(ARM_AM::add, imm)));
1660   else
1661     Inst.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(ARM_AM::sub, imm)));
1662 
1663   return S;
1664 }
1665 
1666 static DecodeStatus DecodeAddrMode7Operand(llvm::MCInst &Inst, unsigned Val,
1667                                    uint64_t Address, const void *Decoder) {
1668   return DecodeGPRRegisterClass(Inst, Val, Address, Decoder);
1669 }
1670 
1671 static DecodeStatus
1672 DecodeBranchImmInstruction(llvm::MCInst &Inst, unsigned Insn,
1673                            uint64_t Address, const void *Decoder) {
1674   DecodeStatus S = MCDisassembler::Success;
1675 
1676   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1677   unsigned imm = fieldFromInstruction32(Insn, 0, 24) << 2;
1678 
1679   if (pred == 0xF) {
1680     Inst.setOpcode(ARM::BLXi);
1681     imm |= fieldFromInstruction32(Insn, 24, 1) << 1;
1682     Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(imm)));
1683     return S;
1684   }
1685 
1686   Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(imm)));
1687   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1688     return MCDisassembler::Fail;
1689 
1690   return S;
1691 }
1692 
1693 
1694 static DecodeStatus DecodeVCVTImmOperand(llvm::MCInst &Inst, unsigned Val,
1695                                  uint64_t Address, const void *Decoder) {
1696   Inst.addOperand(MCOperand::CreateImm(64 - Val));
1697   return MCDisassembler::Success;
1698 }
1699 
1700 static DecodeStatus DecodeAddrMode6Operand(llvm::MCInst &Inst, unsigned Val,
1701                                    uint64_t Address, const void *Decoder) {
1702   DecodeStatus S = MCDisassembler::Success;
1703 
1704   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
1705   unsigned align = fieldFromInstruction32(Val, 4, 2);
1706 
1707   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1708     return MCDisassembler::Fail;
1709   if (!align)
1710     Inst.addOperand(MCOperand::CreateImm(0));
1711   else
1712     Inst.addOperand(MCOperand::CreateImm(4 << align));
1713 
1714   return S;
1715 }
1716 
1717 static DecodeStatus DecodeVLDInstruction(llvm::MCInst &Inst, unsigned Insn,
1718                                    uint64_t Address, const void *Decoder) {
1719   DecodeStatus S = MCDisassembler::Success;
1720 
1721   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
1722   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
1723   unsigned wb = fieldFromInstruction32(Insn, 16, 4);
1724   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1725   Rn |= fieldFromInstruction32(Insn, 4, 2) << 4;
1726   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1727 
1728   // First output register
1729   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
1730     return MCDisassembler::Fail;
1731 
1732   // Second output register
1733   switch (Inst.getOpcode()) {
1734     case ARM::VLD1q8:
1735     case ARM::VLD1q16:
1736     case ARM::VLD1q32:
1737     case ARM::VLD1q64:
1738     case ARM::VLD1q8_UPD:
1739     case ARM::VLD1q16_UPD:
1740     case ARM::VLD1q32_UPD:
1741     case ARM::VLD1q64_UPD:
1742     case ARM::VLD1d8T:
1743     case ARM::VLD1d16T:
1744     case ARM::VLD1d32T:
1745     case ARM::VLD1d64T:
1746     case ARM::VLD1d8T_UPD:
1747     case ARM::VLD1d16T_UPD:
1748     case ARM::VLD1d32T_UPD:
1749     case ARM::VLD1d64T_UPD:
1750     case ARM::VLD1d8Q:
1751     case ARM::VLD1d16Q:
1752     case ARM::VLD1d32Q:
1753     case ARM::VLD1d64Q:
1754     case ARM::VLD1d8Q_UPD:
1755     case ARM::VLD1d16Q_UPD:
1756     case ARM::VLD1d32Q_UPD:
1757     case ARM::VLD1d64Q_UPD:
1758     case ARM::VLD2d8:
1759     case ARM::VLD2d16:
1760     case ARM::VLD2d32:
1761     case ARM::VLD2d8_UPD:
1762     case ARM::VLD2d16_UPD:
1763     case ARM::VLD2d32_UPD:
1764     case ARM::VLD2q8:
1765     case ARM::VLD2q16:
1766     case ARM::VLD2q32:
1767     case ARM::VLD2q8_UPD:
1768     case ARM::VLD2q16_UPD:
1769     case ARM::VLD2q32_UPD:
1770     case ARM::VLD3d8:
1771     case ARM::VLD3d16:
1772     case ARM::VLD3d32:
1773     case ARM::VLD3d8_UPD:
1774     case ARM::VLD3d16_UPD:
1775     case ARM::VLD3d32_UPD:
1776     case ARM::VLD4d8:
1777     case ARM::VLD4d16:
1778     case ARM::VLD4d32:
1779     case ARM::VLD4d8_UPD:
1780     case ARM::VLD4d16_UPD:
1781     case ARM::VLD4d32_UPD:
1782       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
1783         return MCDisassembler::Fail;
1784       break;
1785     case ARM::VLD2b8:
1786     case ARM::VLD2b16:
1787     case ARM::VLD2b32:
1788     case ARM::VLD2b8_UPD:
1789     case ARM::VLD2b16_UPD:
1790     case ARM::VLD2b32_UPD:
1791     case ARM::VLD3q8:
1792     case ARM::VLD3q16:
1793     case ARM::VLD3q32:
1794     case ARM::VLD3q8_UPD:
1795     case ARM::VLD3q16_UPD:
1796     case ARM::VLD3q32_UPD:
1797     case ARM::VLD4q8:
1798     case ARM::VLD4q16:
1799     case ARM::VLD4q32:
1800     case ARM::VLD4q8_UPD:
1801     case ARM::VLD4q16_UPD:
1802     case ARM::VLD4q32_UPD:
1803       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
1804         return MCDisassembler::Fail;
1805     default:
1806       break;
1807   }
1808 
1809   // Third output register
1810   switch(Inst.getOpcode()) {
1811     case ARM::VLD1d8T:
1812     case ARM::VLD1d16T:
1813     case ARM::VLD1d32T:
1814     case ARM::VLD1d64T:
1815     case ARM::VLD1d8T_UPD:
1816     case ARM::VLD1d16T_UPD:
1817     case ARM::VLD1d32T_UPD:
1818     case ARM::VLD1d64T_UPD:
1819     case ARM::VLD1d8Q:
1820     case ARM::VLD1d16Q:
1821     case ARM::VLD1d32Q:
1822     case ARM::VLD1d64Q:
1823     case ARM::VLD1d8Q_UPD:
1824     case ARM::VLD1d16Q_UPD:
1825     case ARM::VLD1d32Q_UPD:
1826     case ARM::VLD1d64Q_UPD:
1827     case ARM::VLD2q8:
1828     case ARM::VLD2q16:
1829     case ARM::VLD2q32:
1830     case ARM::VLD2q8_UPD:
1831     case ARM::VLD2q16_UPD:
1832     case ARM::VLD2q32_UPD:
1833     case ARM::VLD3d8:
1834     case ARM::VLD3d16:
1835     case ARM::VLD3d32:
1836     case ARM::VLD3d8_UPD:
1837     case ARM::VLD3d16_UPD:
1838     case ARM::VLD3d32_UPD:
1839     case ARM::VLD4d8:
1840     case ARM::VLD4d16:
1841     case ARM::VLD4d32:
1842     case ARM::VLD4d8_UPD:
1843     case ARM::VLD4d16_UPD:
1844     case ARM::VLD4d32_UPD:
1845       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
1846         return MCDisassembler::Fail;
1847       break;
1848     case ARM::VLD3q8:
1849     case ARM::VLD3q16:
1850     case ARM::VLD3q32:
1851     case ARM::VLD3q8_UPD:
1852     case ARM::VLD3q16_UPD:
1853     case ARM::VLD3q32_UPD:
1854     case ARM::VLD4q8:
1855     case ARM::VLD4q16:
1856     case ARM::VLD4q32:
1857     case ARM::VLD4q8_UPD:
1858     case ARM::VLD4q16_UPD:
1859     case ARM::VLD4q32_UPD:
1860       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
1861         return MCDisassembler::Fail;
1862       break;
1863     default:
1864       break;
1865   }
1866 
1867   // Fourth output register
1868   switch (Inst.getOpcode()) {
1869     case ARM::VLD1d8Q:
1870     case ARM::VLD1d16Q:
1871     case ARM::VLD1d32Q:
1872     case ARM::VLD1d64Q:
1873     case ARM::VLD1d8Q_UPD:
1874     case ARM::VLD1d16Q_UPD:
1875     case ARM::VLD1d32Q_UPD:
1876     case ARM::VLD1d64Q_UPD:
1877     case ARM::VLD2q8:
1878     case ARM::VLD2q16:
1879     case ARM::VLD2q32:
1880     case ARM::VLD2q8_UPD:
1881     case ARM::VLD2q16_UPD:
1882     case ARM::VLD2q32_UPD:
1883     case ARM::VLD4d8:
1884     case ARM::VLD4d16:
1885     case ARM::VLD4d32:
1886     case ARM::VLD4d8_UPD:
1887     case ARM::VLD4d16_UPD:
1888     case ARM::VLD4d32_UPD:
1889       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
1890         return MCDisassembler::Fail;
1891       break;
1892     case ARM::VLD4q8:
1893     case ARM::VLD4q16:
1894     case ARM::VLD4q32:
1895     case ARM::VLD4q8_UPD:
1896     case ARM::VLD4q16_UPD:
1897     case ARM::VLD4q32_UPD:
1898       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
1899         return MCDisassembler::Fail;
1900       break;
1901     default:
1902       break;
1903   }
1904 
1905   // Writeback operand
1906   switch (Inst.getOpcode()) {
1907     case ARM::VLD1d8_UPD:
1908     case ARM::VLD1d16_UPD:
1909     case ARM::VLD1d32_UPD:
1910     case ARM::VLD1d64_UPD:
1911     case ARM::VLD1q8_UPD:
1912     case ARM::VLD1q16_UPD:
1913     case ARM::VLD1q32_UPD:
1914     case ARM::VLD1q64_UPD:
1915     case ARM::VLD1d8T_UPD:
1916     case ARM::VLD1d16T_UPD:
1917     case ARM::VLD1d32T_UPD:
1918     case ARM::VLD1d64T_UPD:
1919     case ARM::VLD1d8Q_UPD:
1920     case ARM::VLD1d16Q_UPD:
1921     case ARM::VLD1d32Q_UPD:
1922     case ARM::VLD1d64Q_UPD:
1923     case ARM::VLD2d8_UPD:
1924     case ARM::VLD2d16_UPD:
1925     case ARM::VLD2d32_UPD:
1926     case ARM::VLD2q8_UPD:
1927     case ARM::VLD2q16_UPD:
1928     case ARM::VLD2q32_UPD:
1929     case ARM::VLD2b8_UPD:
1930     case ARM::VLD2b16_UPD:
1931     case ARM::VLD2b32_UPD:
1932     case ARM::VLD3d8_UPD:
1933     case ARM::VLD3d16_UPD:
1934     case ARM::VLD3d32_UPD:
1935     case ARM::VLD3q8_UPD:
1936     case ARM::VLD3q16_UPD:
1937     case ARM::VLD3q32_UPD:
1938     case ARM::VLD4d8_UPD:
1939     case ARM::VLD4d16_UPD:
1940     case ARM::VLD4d32_UPD:
1941     case ARM::VLD4q8_UPD:
1942     case ARM::VLD4q16_UPD:
1943     case ARM::VLD4q32_UPD:
1944       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
1945         return MCDisassembler::Fail;
1946       break;
1947     default:
1948       break;
1949   }
1950 
1951   // AddrMode6 Base (register+alignment)
1952   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
1953     return MCDisassembler::Fail;
1954 
1955   // AddrMode6 Offset (register)
1956   if (Rm == 0xD)
1957     Inst.addOperand(MCOperand::CreateReg(0));
1958   else if (Rm != 0xF) {
1959     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1960       return MCDisassembler::Fail;
1961   }
1962 
1963   return S;
1964 }
1965 
1966 static DecodeStatus DecodeVSTInstruction(llvm::MCInst &Inst, unsigned Insn,
1967                                  uint64_t Address, const void *Decoder) {
1968   DecodeStatus S = MCDisassembler::Success;
1969 
1970   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
1971   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
1972   unsigned wb = fieldFromInstruction32(Insn, 16, 4);
1973   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1974   Rn |= fieldFromInstruction32(Insn, 4, 2) << 4;
1975   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1976 
1977   // Writeback Operand
1978   switch (Inst.getOpcode()) {
1979     case ARM::VST1d8_UPD:
1980     case ARM::VST1d16_UPD:
1981     case ARM::VST1d32_UPD:
1982     case ARM::VST1d64_UPD:
1983     case ARM::VST1q8_UPD:
1984     case ARM::VST1q16_UPD:
1985     case ARM::VST1q32_UPD:
1986     case ARM::VST1q64_UPD:
1987     case ARM::VST1d8T_UPD:
1988     case ARM::VST1d16T_UPD:
1989     case ARM::VST1d32T_UPD:
1990     case ARM::VST1d64T_UPD:
1991     case ARM::VST1d8Q_UPD:
1992     case ARM::VST1d16Q_UPD:
1993     case ARM::VST1d32Q_UPD:
1994     case ARM::VST1d64Q_UPD:
1995     case ARM::VST2d8_UPD:
1996     case ARM::VST2d16_UPD:
1997     case ARM::VST2d32_UPD:
1998     case ARM::VST2q8_UPD:
1999     case ARM::VST2q16_UPD:
2000     case ARM::VST2q32_UPD:
2001     case ARM::VST2b8_UPD:
2002     case ARM::VST2b16_UPD:
2003     case ARM::VST2b32_UPD:
2004     case ARM::VST3d8_UPD:
2005     case ARM::VST3d16_UPD:
2006     case ARM::VST3d32_UPD:
2007     case ARM::VST3q8_UPD:
2008     case ARM::VST3q16_UPD:
2009     case ARM::VST3q32_UPD:
2010     case ARM::VST4d8_UPD:
2011     case ARM::VST4d16_UPD:
2012     case ARM::VST4d32_UPD:
2013     case ARM::VST4q8_UPD:
2014     case ARM::VST4q16_UPD:
2015     case ARM::VST4q32_UPD:
2016       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
2017         return MCDisassembler::Fail;
2018       break;
2019     default:
2020       break;
2021   }
2022 
2023   // AddrMode6 Base (register+alignment)
2024   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
2025     return MCDisassembler::Fail;
2026 
2027   // AddrMode6 Offset (register)
2028   if (Rm == 0xD)
2029     Inst.addOperand(MCOperand::CreateReg(0));
2030   else if (Rm != 0xF) {
2031     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2032     return MCDisassembler::Fail;
2033   }
2034 
2035   // First input register
2036   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2037     return MCDisassembler::Fail;
2038 
2039   // Second input register
2040   switch (Inst.getOpcode()) {
2041     case ARM::VST1q8:
2042     case ARM::VST1q16:
2043     case ARM::VST1q32:
2044     case ARM::VST1q64:
2045     case ARM::VST1q8_UPD:
2046     case ARM::VST1q16_UPD:
2047     case ARM::VST1q32_UPD:
2048     case ARM::VST1q64_UPD:
2049     case ARM::VST1d8T:
2050     case ARM::VST1d16T:
2051     case ARM::VST1d32T:
2052     case ARM::VST1d64T:
2053     case ARM::VST1d8T_UPD:
2054     case ARM::VST1d16T_UPD:
2055     case ARM::VST1d32T_UPD:
2056     case ARM::VST1d64T_UPD:
2057     case ARM::VST1d8Q:
2058     case ARM::VST1d16Q:
2059     case ARM::VST1d32Q:
2060     case ARM::VST1d64Q:
2061     case ARM::VST1d8Q_UPD:
2062     case ARM::VST1d16Q_UPD:
2063     case ARM::VST1d32Q_UPD:
2064     case ARM::VST1d64Q_UPD:
2065     case ARM::VST2d8:
2066     case ARM::VST2d16:
2067     case ARM::VST2d32:
2068     case ARM::VST2d8_UPD:
2069     case ARM::VST2d16_UPD:
2070     case ARM::VST2d32_UPD:
2071     case ARM::VST2q8:
2072     case ARM::VST2q16:
2073     case ARM::VST2q32:
2074     case ARM::VST2q8_UPD:
2075     case ARM::VST2q16_UPD:
2076     case ARM::VST2q32_UPD:
2077     case ARM::VST3d8:
2078     case ARM::VST3d16:
2079     case ARM::VST3d32:
2080     case ARM::VST3d8_UPD:
2081     case ARM::VST3d16_UPD:
2082     case ARM::VST3d32_UPD:
2083     case ARM::VST4d8:
2084     case ARM::VST4d16:
2085     case ARM::VST4d32:
2086     case ARM::VST4d8_UPD:
2087     case ARM::VST4d16_UPD:
2088     case ARM::VST4d32_UPD:
2089       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
2090         return MCDisassembler::Fail;
2091       break;
2092     case ARM::VST2b8:
2093     case ARM::VST2b16:
2094     case ARM::VST2b32:
2095     case ARM::VST2b8_UPD:
2096     case ARM::VST2b16_UPD:
2097     case ARM::VST2b32_UPD:
2098     case ARM::VST3q8:
2099     case ARM::VST3q16:
2100     case ARM::VST3q32:
2101     case ARM::VST3q8_UPD:
2102     case ARM::VST3q16_UPD:
2103     case ARM::VST3q32_UPD:
2104     case ARM::VST4q8:
2105     case ARM::VST4q16:
2106     case ARM::VST4q32:
2107     case ARM::VST4q8_UPD:
2108     case ARM::VST4q16_UPD:
2109     case ARM::VST4q32_UPD:
2110       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2111         return MCDisassembler::Fail;
2112       break;
2113     default:
2114       break;
2115   }
2116 
2117   // Third input register
2118   switch (Inst.getOpcode()) {
2119     case ARM::VST1d8T:
2120     case ARM::VST1d16T:
2121     case ARM::VST1d32T:
2122     case ARM::VST1d64T:
2123     case ARM::VST1d8T_UPD:
2124     case ARM::VST1d16T_UPD:
2125     case ARM::VST1d32T_UPD:
2126     case ARM::VST1d64T_UPD:
2127     case ARM::VST1d8Q:
2128     case ARM::VST1d16Q:
2129     case ARM::VST1d32Q:
2130     case ARM::VST1d64Q:
2131     case ARM::VST1d8Q_UPD:
2132     case ARM::VST1d16Q_UPD:
2133     case ARM::VST1d32Q_UPD:
2134     case ARM::VST1d64Q_UPD:
2135     case ARM::VST2q8:
2136     case ARM::VST2q16:
2137     case ARM::VST2q32:
2138     case ARM::VST2q8_UPD:
2139     case ARM::VST2q16_UPD:
2140     case ARM::VST2q32_UPD:
2141     case ARM::VST3d8:
2142     case ARM::VST3d16:
2143     case ARM::VST3d32:
2144     case ARM::VST3d8_UPD:
2145     case ARM::VST3d16_UPD:
2146     case ARM::VST3d32_UPD:
2147     case ARM::VST4d8:
2148     case ARM::VST4d16:
2149     case ARM::VST4d32:
2150     case ARM::VST4d8_UPD:
2151     case ARM::VST4d16_UPD:
2152     case ARM::VST4d32_UPD:
2153       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2154         return MCDisassembler::Fail;
2155       break;
2156     case ARM::VST3q8:
2157     case ARM::VST3q16:
2158     case ARM::VST3q32:
2159     case ARM::VST3q8_UPD:
2160     case ARM::VST3q16_UPD:
2161     case ARM::VST3q32_UPD:
2162     case ARM::VST4q8:
2163     case ARM::VST4q16:
2164     case ARM::VST4q32:
2165     case ARM::VST4q8_UPD:
2166     case ARM::VST4q16_UPD:
2167     case ARM::VST4q32_UPD:
2168       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
2169         return MCDisassembler::Fail;
2170       break;
2171     default:
2172       break;
2173   }
2174 
2175   // Fourth input register
2176   switch (Inst.getOpcode()) {
2177     case ARM::VST1d8Q:
2178     case ARM::VST1d16Q:
2179     case ARM::VST1d32Q:
2180     case ARM::VST1d64Q:
2181     case ARM::VST1d8Q_UPD:
2182     case ARM::VST1d16Q_UPD:
2183     case ARM::VST1d32Q_UPD:
2184     case ARM::VST1d64Q_UPD:
2185     case ARM::VST2q8:
2186     case ARM::VST2q16:
2187     case ARM::VST2q32:
2188     case ARM::VST2q8_UPD:
2189     case ARM::VST2q16_UPD:
2190     case ARM::VST2q32_UPD:
2191     case ARM::VST4d8:
2192     case ARM::VST4d16:
2193     case ARM::VST4d32:
2194     case ARM::VST4d8_UPD:
2195     case ARM::VST4d16_UPD:
2196     case ARM::VST4d32_UPD:
2197       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
2198         return MCDisassembler::Fail;
2199       break;
2200     case ARM::VST4q8:
2201     case ARM::VST4q16:
2202     case ARM::VST4q32:
2203     case ARM::VST4q8_UPD:
2204     case ARM::VST4q16_UPD:
2205     case ARM::VST4q32_UPD:
2206       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
2207         return MCDisassembler::Fail;
2208       break;
2209     default:
2210       break;
2211   }
2212 
2213   return S;
2214 }
2215 
2216 static DecodeStatus DecodeVLD1DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2217                                     uint64_t Address, const void *Decoder) {
2218   DecodeStatus S = MCDisassembler::Success;
2219 
2220   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2221   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2222   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2223   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2224   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2225   unsigned size = fieldFromInstruction32(Insn, 6, 2);
2226   unsigned regs = fieldFromInstruction32(Insn, 5, 1) + 1;
2227 
2228   align *= (1 << size);
2229 
2230   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2231     return MCDisassembler::Fail;
2232   if (regs == 2) {
2233     if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
2234       return MCDisassembler::Fail;
2235   }
2236   if (Rm != 0xF) {
2237     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2238       return MCDisassembler::Fail;
2239   }
2240 
2241   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2242     return MCDisassembler::Fail;
2243   Inst.addOperand(MCOperand::CreateImm(align));
2244 
2245   if (Rm == 0xD)
2246     Inst.addOperand(MCOperand::CreateReg(0));
2247   else if (Rm != 0xF) {
2248     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2249       return MCDisassembler::Fail;
2250   }
2251 
2252   return S;
2253 }
2254 
2255 static DecodeStatus DecodeVLD2DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2256                                     uint64_t Address, const void *Decoder) {
2257   DecodeStatus S = MCDisassembler::Success;
2258 
2259   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2260   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2261   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2262   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2263   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2264   unsigned size = 1 << fieldFromInstruction32(Insn, 6, 2);
2265   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2266   align *= 2*size;
2267 
2268   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2269     return MCDisassembler::Fail;
2270   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
2271     return MCDisassembler::Fail;
2272   if (Rm != 0xF) {
2273     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2274       return MCDisassembler::Fail;
2275   }
2276 
2277   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2278     return MCDisassembler::Fail;
2279   Inst.addOperand(MCOperand::CreateImm(align));
2280 
2281   if (Rm == 0xD)
2282     Inst.addOperand(MCOperand::CreateReg(0));
2283   else if (Rm != 0xF) {
2284     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2285       return MCDisassembler::Fail;
2286   }
2287 
2288   return S;
2289 }
2290 
2291 static DecodeStatus DecodeVLD3DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2292                                     uint64_t Address, const void *Decoder) {
2293   DecodeStatus S = MCDisassembler::Success;
2294 
2295   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2296   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2297   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2298   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2299   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2300 
2301   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2302     return MCDisassembler::Fail;
2303   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
2304     return MCDisassembler::Fail;
2305   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
2306     return MCDisassembler::Fail;
2307   if (Rm != 0xF) {
2308     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2309       return MCDisassembler::Fail;
2310   }
2311 
2312   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2313     return MCDisassembler::Fail;
2314   Inst.addOperand(MCOperand::CreateImm(0));
2315 
2316   if (Rm == 0xD)
2317     Inst.addOperand(MCOperand::CreateReg(0));
2318   else if (Rm != 0xF) {
2319     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2320       return MCDisassembler::Fail;
2321   }
2322 
2323   return S;
2324 }
2325 
2326 static DecodeStatus DecodeVLD4DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2327                                     uint64_t Address, const void *Decoder) {
2328   DecodeStatus S = MCDisassembler::Success;
2329 
2330   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2331   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2332   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2333   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2334   unsigned size = fieldFromInstruction32(Insn, 6, 2);
2335   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2336   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2337 
2338   if (size == 0x3) {
2339     size = 4;
2340     align = 16;
2341   } else {
2342     if (size == 2) {
2343       size = 1 << size;
2344       align *= 8;
2345     } else {
2346       size = 1 << size;
2347       align *= 4*size;
2348     }
2349   }
2350 
2351   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2352     return MCDisassembler::Fail;
2353   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
2354     return MCDisassembler::Fail;
2355   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
2356     return MCDisassembler::Fail;
2357   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3*inc)%32, Address, Decoder)))
2358     return MCDisassembler::Fail;
2359   if (Rm != 0xF) {
2360     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2361       return MCDisassembler::Fail;
2362   }
2363 
2364   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2365     return MCDisassembler::Fail;
2366   Inst.addOperand(MCOperand::CreateImm(align));
2367 
2368   if (Rm == 0xD)
2369     Inst.addOperand(MCOperand::CreateReg(0));
2370   else if (Rm != 0xF) {
2371     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2372       return MCDisassembler::Fail;
2373   }
2374 
2375   return S;
2376 }
2377 
2378 static DecodeStatus
2379 DecodeNEONModImmInstruction(llvm::MCInst &Inst, unsigned Insn,
2380                             uint64_t Address, const void *Decoder) {
2381   DecodeStatus S = MCDisassembler::Success;
2382 
2383   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2384   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2385   unsigned imm = fieldFromInstruction32(Insn, 0, 4);
2386   imm |= fieldFromInstruction32(Insn, 16, 3) << 4;
2387   imm |= fieldFromInstruction32(Insn, 24, 1) << 7;
2388   imm |= fieldFromInstruction32(Insn, 8, 4) << 8;
2389   imm |= fieldFromInstruction32(Insn, 5, 1) << 12;
2390   unsigned Q = fieldFromInstruction32(Insn, 6, 1);
2391 
2392   if (Q) {
2393     if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2394     return MCDisassembler::Fail;
2395   } else {
2396     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2397     return MCDisassembler::Fail;
2398   }
2399 
2400   Inst.addOperand(MCOperand::CreateImm(imm));
2401 
2402   switch (Inst.getOpcode()) {
2403     case ARM::VORRiv4i16:
2404     case ARM::VORRiv2i32:
2405     case ARM::VBICiv4i16:
2406     case ARM::VBICiv2i32:
2407       if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2408         return MCDisassembler::Fail;
2409       break;
2410     case ARM::VORRiv8i16:
2411     case ARM::VORRiv4i32:
2412     case ARM::VBICiv8i16:
2413     case ARM::VBICiv4i32:
2414       if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2415         return MCDisassembler::Fail;
2416       break;
2417     default:
2418       break;
2419   }
2420 
2421   return S;
2422 }
2423 
2424 static DecodeStatus DecodeVSHLMaxInstruction(llvm::MCInst &Inst, unsigned Insn,
2425                                         uint64_t Address, const void *Decoder) {
2426   DecodeStatus S = MCDisassembler::Success;
2427 
2428   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2429   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2430   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2431   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
2432   unsigned size = fieldFromInstruction32(Insn, 18, 2);
2433 
2434   if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2435     return MCDisassembler::Fail;
2436   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
2437     return MCDisassembler::Fail;
2438   Inst.addOperand(MCOperand::CreateImm(8 << size));
2439 
2440   return S;
2441 }
2442 
2443 static DecodeStatus DecodeShiftRight8Imm(llvm::MCInst &Inst, unsigned Val,
2444                                uint64_t Address, const void *Decoder) {
2445   Inst.addOperand(MCOperand::CreateImm(8 - Val));
2446   return MCDisassembler::Success;
2447 }
2448 
2449 static DecodeStatus DecodeShiftRight16Imm(llvm::MCInst &Inst, unsigned Val,
2450                                uint64_t Address, const void *Decoder) {
2451   Inst.addOperand(MCOperand::CreateImm(16 - Val));
2452   return MCDisassembler::Success;
2453 }
2454 
2455 static DecodeStatus DecodeShiftRight32Imm(llvm::MCInst &Inst, unsigned Val,
2456                                uint64_t Address, const void *Decoder) {
2457   Inst.addOperand(MCOperand::CreateImm(32 - Val));
2458   return MCDisassembler::Success;
2459 }
2460 
2461 static DecodeStatus DecodeShiftRight64Imm(llvm::MCInst &Inst, unsigned Val,
2462                                uint64_t Address, const void *Decoder) {
2463   Inst.addOperand(MCOperand::CreateImm(64 - Val));
2464   return MCDisassembler::Success;
2465 }
2466 
2467 static DecodeStatus DecodeTBLInstruction(llvm::MCInst &Inst, unsigned Insn,
2468                                uint64_t Address, const void *Decoder) {
2469   DecodeStatus S = MCDisassembler::Success;
2470 
2471   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2472   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2473   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2474   Rn |= fieldFromInstruction32(Insn, 7, 1) << 4;
2475   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2476   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
2477   unsigned op = fieldFromInstruction32(Insn, 6, 1);
2478   unsigned length = fieldFromInstruction32(Insn, 8, 2) + 1;
2479 
2480   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2481     return MCDisassembler::Fail;
2482   if (op) {
2483     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2484     return MCDisassembler::Fail; // Writeback
2485   }
2486 
2487   for (unsigned i = 0; i < length; ++i) {
2488     if (!Check(S, DecodeDPRRegisterClass(Inst, (Rn+i)%32, Address, Decoder)))
2489     return MCDisassembler::Fail;
2490   }
2491 
2492   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
2493     return MCDisassembler::Fail;
2494 
2495   return S;
2496 }
2497 
2498 static DecodeStatus DecodeVFPfpImm(llvm::MCInst &Inst, unsigned Val,
2499                             uint64_t Address, const void *Decoder) {
2500   // The immediate needs to be a fully instantiated float.  However, the
2501   // auto-generated decoder is only able to fill in some of the bits
2502   // necessary.  For instance, the 'b' bit is replicated multiple times,
2503   // and is even present in inverted form in one bit.  We do a little
2504   // binary parsing here to fill in those missing bits, and then
2505   // reinterpret it all as a float.
2506   union {
2507     uint32_t integer;
2508     float fp;
2509   } fp_conv;
2510 
2511   fp_conv.integer = Val;
2512   uint32_t b = fieldFromInstruction32(Val, 25, 1);
2513   fp_conv.integer |= b << 26;
2514   fp_conv.integer |= b << 27;
2515   fp_conv.integer |= b << 28;
2516   fp_conv.integer |= b << 29;
2517   fp_conv.integer |= (~b & 0x1) << 30;
2518 
2519   Inst.addOperand(MCOperand::CreateFPImm(fp_conv.fp));
2520   return MCDisassembler::Success;
2521 }
2522 
2523 static DecodeStatus DecodeThumbAddSpecialReg(llvm::MCInst &Inst, uint16_t Insn,
2524                                      uint64_t Address, const void *Decoder) {
2525   DecodeStatus S = MCDisassembler::Success;
2526 
2527   unsigned dst = fieldFromInstruction16(Insn, 8, 3);
2528   unsigned imm = fieldFromInstruction16(Insn, 0, 8);
2529 
2530   if (!Check(S, DecodetGPRRegisterClass(Inst, dst, Address, Decoder)))
2531     return MCDisassembler::Fail;
2532 
2533   switch(Inst.getOpcode()) {
2534     default:
2535       return MCDisassembler::Fail;
2536     case ARM::tADR:
2537       break; // tADR does not explicitly represent the PC as an operand.
2538     case ARM::tADDrSPi:
2539       Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2540       break;
2541   }
2542 
2543   Inst.addOperand(MCOperand::CreateImm(imm));
2544   return S;
2545 }
2546 
2547 static DecodeStatus DecodeThumbBROperand(llvm::MCInst &Inst, unsigned Val,
2548                                  uint64_t Address, const void *Decoder) {
2549   Inst.addOperand(MCOperand::CreateImm(SignExtend32<12>(Val << 1)));
2550   return MCDisassembler::Success;
2551 }
2552 
2553 static DecodeStatus DecodeT2BROperand(llvm::MCInst &Inst, unsigned Val,
2554                                  uint64_t Address, const void *Decoder) {
2555   Inst.addOperand(MCOperand::CreateImm(SignExtend32<21>(Val)));
2556   return MCDisassembler::Success;
2557 }
2558 
2559 static DecodeStatus DecodeThumbCmpBROperand(llvm::MCInst &Inst, unsigned Val,
2560                                  uint64_t Address, const void *Decoder) {
2561   Inst.addOperand(MCOperand::CreateImm(SignExtend32<7>(Val << 1)));
2562   return MCDisassembler::Success;
2563 }
2564 
2565 static DecodeStatus DecodeThumbAddrModeRR(llvm::MCInst &Inst, unsigned Val,
2566                                  uint64_t Address, const void *Decoder) {
2567   DecodeStatus S = MCDisassembler::Success;
2568 
2569   unsigned Rn = fieldFromInstruction32(Val, 0, 3);
2570   unsigned Rm = fieldFromInstruction32(Val, 3, 3);
2571 
2572   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
2573     return MCDisassembler::Fail;
2574   if (!Check(S, DecodetGPRRegisterClass(Inst, Rm, Address, Decoder)))
2575     return MCDisassembler::Fail;
2576 
2577   return S;
2578 }
2579 
2580 static DecodeStatus DecodeThumbAddrModeIS(llvm::MCInst &Inst, unsigned Val,
2581                                   uint64_t Address, const void *Decoder) {
2582   DecodeStatus S = MCDisassembler::Success;
2583 
2584   unsigned Rn = fieldFromInstruction32(Val, 0, 3);
2585   unsigned imm = fieldFromInstruction32(Val, 3, 5);
2586 
2587   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
2588     return MCDisassembler::Fail;
2589   Inst.addOperand(MCOperand::CreateImm(imm));
2590 
2591   return S;
2592 }
2593 
2594 static DecodeStatus DecodeThumbAddrModePC(llvm::MCInst &Inst, unsigned Val,
2595                                   uint64_t Address, const void *Decoder) {
2596   Inst.addOperand(MCOperand::CreateImm(Val << 2));
2597 
2598   return MCDisassembler::Success;
2599 }
2600 
2601 static DecodeStatus DecodeThumbAddrModeSP(llvm::MCInst &Inst, unsigned Val,
2602                                   uint64_t Address, const void *Decoder) {
2603   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2604   Inst.addOperand(MCOperand::CreateImm(Val));
2605 
2606   return MCDisassembler::Success;
2607 }
2608 
2609 static DecodeStatus DecodeT2AddrModeSOReg(llvm::MCInst &Inst, unsigned Val,
2610                                   uint64_t Address, const void *Decoder) {
2611   DecodeStatus S = MCDisassembler::Success;
2612 
2613   unsigned Rn = fieldFromInstruction32(Val, 6, 4);
2614   unsigned Rm = fieldFromInstruction32(Val, 2, 4);
2615   unsigned imm = fieldFromInstruction32(Val, 0, 2);
2616 
2617   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2618     return MCDisassembler::Fail;
2619   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
2620     return MCDisassembler::Fail;
2621   Inst.addOperand(MCOperand::CreateImm(imm));
2622 
2623   return S;
2624 }
2625 
2626 static DecodeStatus DecodeT2LoadShift(llvm::MCInst &Inst, unsigned Insn,
2627                               uint64_t Address, const void *Decoder) {
2628   DecodeStatus S = MCDisassembler::Success;
2629 
2630   switch (Inst.getOpcode()) {
2631     case ARM::t2PLDs:
2632     case ARM::t2PLDWs:
2633     case ARM::t2PLIs:
2634       break;
2635     default: {
2636       unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2637       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
2638     return MCDisassembler::Fail;
2639     }
2640   }
2641 
2642   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2643   if (Rn == 0xF) {
2644     switch (Inst.getOpcode()) {
2645       case ARM::t2LDRBs:
2646         Inst.setOpcode(ARM::t2LDRBpci);
2647         break;
2648       case ARM::t2LDRHs:
2649         Inst.setOpcode(ARM::t2LDRHpci);
2650         break;
2651       case ARM::t2LDRSHs:
2652         Inst.setOpcode(ARM::t2LDRSHpci);
2653         break;
2654       case ARM::t2LDRSBs:
2655         Inst.setOpcode(ARM::t2LDRSBpci);
2656         break;
2657       case ARM::t2PLDs:
2658         Inst.setOpcode(ARM::t2PLDi12);
2659         Inst.addOperand(MCOperand::CreateReg(ARM::PC));
2660         break;
2661       default:
2662         return MCDisassembler::Fail;
2663     }
2664 
2665     int imm = fieldFromInstruction32(Insn, 0, 12);
2666     if (!fieldFromInstruction32(Insn, 23, 1)) imm *= -1;
2667     Inst.addOperand(MCOperand::CreateImm(imm));
2668 
2669     return S;
2670   }
2671 
2672   unsigned addrmode = fieldFromInstruction32(Insn, 4, 2);
2673   addrmode |= fieldFromInstruction32(Insn, 0, 4) << 2;
2674   addrmode |= fieldFromInstruction32(Insn, 16, 4) << 6;
2675   if (!Check(S, DecodeT2AddrModeSOReg(Inst, addrmode, Address, Decoder)))
2676     return MCDisassembler::Fail;
2677 
2678   return S;
2679 }
2680 
2681 static DecodeStatus DecodeT2Imm8S4(llvm::MCInst &Inst, unsigned Val,
2682                            uint64_t Address, const void *Decoder) {
2683   int imm = Val & 0xFF;
2684   if (!(Val & 0x100)) imm *= -1;
2685   Inst.addOperand(MCOperand::CreateImm(imm << 2));
2686 
2687   return MCDisassembler::Success;
2688 }
2689 
2690 static DecodeStatus DecodeT2AddrModeImm8s4(llvm::MCInst &Inst, unsigned Val,
2691                                    uint64_t Address, const void *Decoder) {
2692   DecodeStatus S = MCDisassembler::Success;
2693 
2694   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
2695   unsigned imm = fieldFromInstruction32(Val, 0, 9);
2696 
2697   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2698     return MCDisassembler::Fail;
2699   if (!Check(S, DecodeT2Imm8S4(Inst, imm, Address, Decoder)))
2700     return MCDisassembler::Fail;
2701 
2702   return S;
2703 }
2704 
2705 static DecodeStatus DecodeT2AddrModeImm0_1020s4(llvm::MCInst &Inst,unsigned Val,
2706                                    uint64_t Address, const void *Decoder) {
2707   DecodeStatus S = MCDisassembler::Success;
2708 
2709   unsigned Rn = fieldFromInstruction32(Val, 8, 4);
2710   unsigned imm = fieldFromInstruction32(Val, 0, 8);
2711 
2712   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
2713     return MCDisassembler::Fail;
2714 
2715   Inst.addOperand(MCOperand::CreateImm(imm));
2716 
2717   return S;
2718 }
2719 
2720 static DecodeStatus DecodeT2Imm8(llvm::MCInst &Inst, unsigned Val,
2721                          uint64_t Address, const void *Decoder) {
2722   int imm = Val & 0xFF;
2723   if (!(Val & 0x100)) imm *= -1;
2724   Inst.addOperand(MCOperand::CreateImm(imm));
2725 
2726   return MCDisassembler::Success;
2727 }
2728 
2729 
2730 static DecodeStatus DecodeT2AddrModeImm8(llvm::MCInst &Inst, unsigned Val,
2731                                  uint64_t Address, const void *Decoder) {
2732   DecodeStatus S = MCDisassembler::Success;
2733 
2734   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
2735   unsigned imm = fieldFromInstruction32(Val, 0, 9);
2736 
2737   // Some instructions always use an additive offset.
2738   switch (Inst.getOpcode()) {
2739     case ARM::t2LDRT:
2740     case ARM::t2LDRBT:
2741     case ARM::t2LDRHT:
2742     case ARM::t2LDRSBT:
2743     case ARM::t2LDRSHT:
2744       imm |= 0x100;
2745       break;
2746     default:
2747       break;
2748   }
2749 
2750   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2751     return MCDisassembler::Fail;
2752   if (!Check(S, DecodeT2Imm8(Inst, imm, Address, Decoder)))
2753     return MCDisassembler::Fail;
2754 
2755   return S;
2756 }
2757 
2758 
2759 static DecodeStatus DecodeT2AddrModeImm12(llvm::MCInst &Inst, unsigned Val,
2760                                   uint64_t Address, const void *Decoder) {
2761   DecodeStatus S = MCDisassembler::Success;
2762 
2763   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
2764   unsigned imm = fieldFromInstruction32(Val, 0, 12);
2765 
2766   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2767     return MCDisassembler::Fail;
2768   Inst.addOperand(MCOperand::CreateImm(imm));
2769 
2770   return S;
2771 }
2772 
2773 
2774 static DecodeStatus DecodeThumbAddSPImm(llvm::MCInst &Inst, uint16_t Insn,
2775                                 uint64_t Address, const void *Decoder) {
2776   unsigned imm = fieldFromInstruction16(Insn, 0, 7);
2777 
2778   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2779   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2780   Inst.addOperand(MCOperand::CreateImm(imm));
2781 
2782   return MCDisassembler::Success;
2783 }
2784 
2785 static DecodeStatus DecodeThumbAddSPReg(llvm::MCInst &Inst, uint16_t Insn,
2786                                 uint64_t Address, const void *Decoder) {
2787   DecodeStatus S = MCDisassembler::Success;
2788 
2789   if (Inst.getOpcode() == ARM::tADDrSP) {
2790     unsigned Rdm = fieldFromInstruction16(Insn, 0, 3);
2791     Rdm |= fieldFromInstruction16(Insn, 7, 1) << 3;
2792 
2793     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
2794     return MCDisassembler::Fail;
2795     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
2796     return MCDisassembler::Fail;
2797     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2798   } else if (Inst.getOpcode() == ARM::tADDspr) {
2799     unsigned Rm = fieldFromInstruction16(Insn, 3, 4);
2800 
2801     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2802     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2803     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2804     return MCDisassembler::Fail;
2805   }
2806 
2807   return S;
2808 }
2809 
2810 static DecodeStatus DecodeThumbCPS(llvm::MCInst &Inst, uint16_t Insn,
2811                            uint64_t Address, const void *Decoder) {
2812   unsigned imod = fieldFromInstruction16(Insn, 4, 1) | 0x2;
2813   unsigned flags = fieldFromInstruction16(Insn, 0, 3);
2814 
2815   Inst.addOperand(MCOperand::CreateImm(imod));
2816   Inst.addOperand(MCOperand::CreateImm(flags));
2817 
2818   return MCDisassembler::Success;
2819 }
2820 
2821 static DecodeStatus DecodePostIdxReg(llvm::MCInst &Inst, unsigned Insn,
2822                              uint64_t Address, const void *Decoder) {
2823   DecodeStatus S = MCDisassembler::Success;
2824   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2825   unsigned add = fieldFromInstruction32(Insn, 4, 1);
2826 
2827   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2828     return MCDisassembler::Fail;
2829   Inst.addOperand(MCOperand::CreateImm(add));
2830 
2831   return S;
2832 }
2833 
2834 static DecodeStatus DecodeThumbBLXOffset(llvm::MCInst &Inst, unsigned Val,
2835                                  uint64_t Address, const void *Decoder) {
2836   Inst.addOperand(MCOperand::CreateImm(SignExtend32<22>(Val << 1)));
2837   return MCDisassembler::Success;
2838 }
2839 
2840 static DecodeStatus DecodeCoprocessor(llvm::MCInst &Inst, unsigned Val,
2841                               uint64_t Address, const void *Decoder) {
2842   if (Val == 0xA || Val == 0xB)
2843     return MCDisassembler::Fail;
2844 
2845   Inst.addOperand(MCOperand::CreateImm(Val));
2846   return MCDisassembler::Success;
2847 }
2848 
2849 static DecodeStatus
2850 DecodeThumb2BCCInstruction(llvm::MCInst &Inst, unsigned Insn,
2851                            uint64_t Address, const void *Decoder) {
2852   DecodeStatus S = MCDisassembler::Success;
2853 
2854   unsigned pred = fieldFromInstruction32(Insn, 22, 4);
2855   if (pred == 0xE || pred == 0xF) {
2856     unsigned opc = fieldFromInstruction32(Insn, 4, 28);
2857     switch (opc) {
2858       default:
2859         return MCDisassembler::Fail;
2860       case 0xf3bf8f4:
2861         Inst.setOpcode(ARM::t2DSB);
2862         break;
2863       case 0xf3bf8f5:
2864         Inst.setOpcode(ARM::t2DMB);
2865         break;
2866       case 0xf3bf8f6:
2867         Inst.setOpcode(ARM::t2ISB);
2868         break;
2869     }
2870 
2871     unsigned imm = fieldFromInstruction32(Insn, 0, 4);
2872     return DecodeMemBarrierOption(Inst, imm, Address, Decoder);
2873   }
2874 
2875   unsigned brtarget = fieldFromInstruction32(Insn, 0, 11) << 1;
2876   brtarget |= fieldFromInstruction32(Insn, 11, 1) << 19;
2877   brtarget |= fieldFromInstruction32(Insn, 13, 1) << 18;
2878   brtarget |= fieldFromInstruction32(Insn, 16, 6) << 12;
2879   brtarget |= fieldFromInstruction32(Insn, 26, 1) << 20;
2880 
2881   if (!Check(S, DecodeT2BROperand(Inst, brtarget, Address, Decoder)))
2882     return MCDisassembler::Fail;
2883   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2884     return MCDisassembler::Fail;
2885 
2886   return S;
2887 }
2888 
2889 // Decode a shifted immediate operand.  These basically consist
2890 // of an 8-bit value, and a 4-bit directive that specifies either
2891 // a splat operation or a rotation.
2892 static DecodeStatus DecodeT2SOImm(llvm::MCInst &Inst, unsigned Val,
2893                           uint64_t Address, const void *Decoder) {
2894   unsigned ctrl = fieldFromInstruction32(Val, 10, 2);
2895   if (ctrl == 0) {
2896     unsigned byte = fieldFromInstruction32(Val, 8, 2);
2897     unsigned imm = fieldFromInstruction32(Val, 0, 8);
2898     switch (byte) {
2899       case 0:
2900         Inst.addOperand(MCOperand::CreateImm(imm));
2901         break;
2902       case 1:
2903         Inst.addOperand(MCOperand::CreateImm((imm << 16) | imm));
2904         break;
2905       case 2:
2906         Inst.addOperand(MCOperand::CreateImm((imm << 24) | (imm << 8)));
2907         break;
2908       case 3:
2909         Inst.addOperand(MCOperand::CreateImm((imm << 24) | (imm << 16) |
2910                                              (imm << 8)  |  imm));
2911         break;
2912     }
2913   } else {
2914     unsigned unrot = fieldFromInstruction32(Val, 0, 7) | 0x80;
2915     unsigned rot = fieldFromInstruction32(Val, 7, 5);
2916     unsigned imm = (unrot >> rot) | (unrot << ((32-rot)&31));
2917     Inst.addOperand(MCOperand::CreateImm(imm));
2918   }
2919 
2920   return MCDisassembler::Success;
2921 }
2922 
2923 static DecodeStatus
2924 DecodeThumbBCCTargetOperand(llvm::MCInst &Inst, unsigned Val,
2925                             uint64_t Address, const void *Decoder){
2926   Inst.addOperand(MCOperand::CreateImm(Val << 1));
2927   return MCDisassembler::Success;
2928 }
2929 
2930 static DecodeStatus DecodeThumbBLTargetOperand(llvm::MCInst &Inst, unsigned Val,
2931                                        uint64_t Address, const void *Decoder){
2932   Inst.addOperand(MCOperand::CreateImm(SignExtend32<22>(Val << 1)));
2933   return MCDisassembler::Success;
2934 }
2935 
2936 static DecodeStatus DecodeMemBarrierOption(llvm::MCInst &Inst, unsigned Val,
2937                                    uint64_t Address, const void *Decoder) {
2938   switch (Val) {
2939   default:
2940     return MCDisassembler::Fail;
2941   case 0xF: // SY
2942   case 0xE: // ST
2943   case 0xB: // ISH
2944   case 0xA: // ISHST
2945   case 0x7: // NSH
2946   case 0x6: // NSHST
2947   case 0x3: // OSH
2948   case 0x2: // OSHST
2949     break;
2950   }
2951 
2952   Inst.addOperand(MCOperand::CreateImm(Val));
2953   return MCDisassembler::Success;
2954 }
2955 
2956 static DecodeStatus DecodeMSRMask(llvm::MCInst &Inst, unsigned Val,
2957                           uint64_t Address, const void *Decoder) {
2958   if (!Val) return MCDisassembler::Fail;
2959   Inst.addOperand(MCOperand::CreateImm(Val));
2960   return MCDisassembler::Success;
2961 }
2962 
2963 static DecodeStatus DecodeDoubleRegLoad(llvm::MCInst &Inst, unsigned Insn,
2964                                         uint64_t Address, const void *Decoder) {
2965   DecodeStatus S = MCDisassembler::Success;
2966 
2967   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2968   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2969   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
2970 
2971   if ((Rt & 1) || Rt == 0xE || Rn == 0xF) return MCDisassembler::Fail;
2972 
2973   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
2974     return MCDisassembler::Fail;
2975   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
2976     return MCDisassembler::Fail;
2977   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2978     return MCDisassembler::Fail;
2979   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2980     return MCDisassembler::Fail;
2981 
2982   return S;
2983 }
2984 
2985 
2986 static DecodeStatus DecodeDoubleRegStore(llvm::MCInst &Inst, unsigned Insn,
2987                                          uint64_t Address, const void *Decoder){
2988   DecodeStatus S = MCDisassembler::Success;
2989 
2990   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2991   unsigned Rt = fieldFromInstruction32(Insn, 0, 4);
2992   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2993   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
2994 
2995   if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
2996     return MCDisassembler::Fail;
2997 
2998   if ((Rt & 1) || Rt == 0xE || Rn == 0xF) return MCDisassembler::Fail;
2999   if (Rd == Rn || Rd == Rt || Rd == Rt+1) return MCDisassembler::Fail;
3000 
3001   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3002     return MCDisassembler::Fail;
3003   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
3004     return MCDisassembler::Fail;
3005   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3006     return MCDisassembler::Fail;
3007   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3008     return MCDisassembler::Fail;
3009 
3010   return S;
3011 }
3012 
3013 static DecodeStatus DecodeLDRPreImm(llvm::MCInst &Inst, unsigned Insn,
3014                             uint64_t Address, const void *Decoder) {
3015   DecodeStatus S = MCDisassembler::Success;
3016 
3017   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3018   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3019   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3020   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3021   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3022   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3023 
3024   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3025 
3026   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3027     return MCDisassembler::Fail;
3028   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3029     return MCDisassembler::Fail;
3030   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
3031     return MCDisassembler::Fail;
3032   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3033     return MCDisassembler::Fail;
3034 
3035   return S;
3036 }
3037 
3038 static DecodeStatus DecodeLDRPreReg(llvm::MCInst &Inst, unsigned Insn,
3039                             uint64_t Address, const void *Decoder) {
3040   DecodeStatus S = MCDisassembler::Success;
3041 
3042   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3043   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3044   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3045   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3046   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3047   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3048   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3049 
3050   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3051   if (Rm == 0xF) S = MCDisassembler::SoftFail;
3052 
3053   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3054     return MCDisassembler::Fail;
3055   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3056     return MCDisassembler::Fail;
3057   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
3058     return MCDisassembler::Fail;
3059   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3060     return MCDisassembler::Fail;
3061 
3062   return S;
3063 }
3064 
3065 
3066 static DecodeStatus DecodeSTRPreImm(llvm::MCInst &Inst, unsigned Insn,
3067                             uint64_t Address, const void *Decoder) {
3068   DecodeStatus S = MCDisassembler::Success;
3069 
3070   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3071   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3072   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3073   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3074   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3075   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3076 
3077   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3078 
3079   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3080     return MCDisassembler::Fail;
3081   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3082     return MCDisassembler::Fail;
3083   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
3084     return MCDisassembler::Fail;
3085   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3086     return MCDisassembler::Fail;
3087 
3088   return S;
3089 }
3090 
3091 static DecodeStatus DecodeSTRPreReg(llvm::MCInst &Inst, unsigned Insn,
3092                             uint64_t Address, const void *Decoder) {
3093   DecodeStatus S = MCDisassembler::Success;
3094 
3095   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3096   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3097   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3098   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3099   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3100   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3101 
3102   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3103 
3104   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3105     return MCDisassembler::Fail;
3106   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3107     return MCDisassembler::Fail;
3108   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
3109     return MCDisassembler::Fail;
3110   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3111     return MCDisassembler::Fail;
3112 
3113   return S;
3114 }
3115 
3116 static DecodeStatus DecodeVLD1LN(llvm::MCInst &Inst, unsigned Insn,
3117                          uint64_t Address, const void *Decoder) {
3118   DecodeStatus S = MCDisassembler::Success;
3119 
3120   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3121   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3122   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3123   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3124   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3125 
3126   unsigned align = 0;
3127   unsigned index = 0;
3128   switch (size) {
3129     default:
3130       return MCDisassembler::Fail;
3131     case 0:
3132       if (fieldFromInstruction32(Insn, 4, 1))
3133         return MCDisassembler::Fail; // UNDEFINED
3134       index = fieldFromInstruction32(Insn, 5, 3);
3135       break;
3136     case 1:
3137       if (fieldFromInstruction32(Insn, 5, 1))
3138         return MCDisassembler::Fail; // UNDEFINED
3139       index = fieldFromInstruction32(Insn, 6, 2);
3140       if (fieldFromInstruction32(Insn, 4, 1))
3141         align = 2;
3142       break;
3143     case 2:
3144       if (fieldFromInstruction32(Insn, 6, 1))
3145         return MCDisassembler::Fail; // UNDEFINED
3146       index = fieldFromInstruction32(Insn, 7, 1);
3147       if (fieldFromInstruction32(Insn, 4, 2) != 0)
3148         align = 4;
3149   }
3150 
3151   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3152     return MCDisassembler::Fail;
3153   if (Rm != 0xF) { // Writeback
3154     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3155       return MCDisassembler::Fail;
3156   }
3157   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3158     return MCDisassembler::Fail;
3159   Inst.addOperand(MCOperand::CreateImm(align));
3160   if (Rm != 0xF) {
3161     if (Rm != 0xD) {
3162       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3163         return MCDisassembler::Fail;
3164     } else
3165       Inst.addOperand(MCOperand::CreateReg(0));
3166   }
3167 
3168   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3169     return MCDisassembler::Fail;
3170   Inst.addOperand(MCOperand::CreateImm(index));
3171 
3172   return S;
3173 }
3174 
3175 static DecodeStatus DecodeVST1LN(llvm::MCInst &Inst, unsigned Insn,
3176                          uint64_t Address, const void *Decoder) {
3177   DecodeStatus S = MCDisassembler::Success;
3178 
3179   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3180   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3181   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3182   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3183   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3184 
3185   unsigned align = 0;
3186   unsigned index = 0;
3187   switch (size) {
3188     default:
3189       return MCDisassembler::Fail;
3190     case 0:
3191       if (fieldFromInstruction32(Insn, 4, 1))
3192         return MCDisassembler::Fail; // UNDEFINED
3193       index = fieldFromInstruction32(Insn, 5, 3);
3194       break;
3195     case 1:
3196       if (fieldFromInstruction32(Insn, 5, 1))
3197         return MCDisassembler::Fail; // UNDEFINED
3198       index = fieldFromInstruction32(Insn, 6, 2);
3199       if (fieldFromInstruction32(Insn, 4, 1))
3200         align = 2;
3201       break;
3202     case 2:
3203       if (fieldFromInstruction32(Insn, 6, 1))
3204         return MCDisassembler::Fail; // UNDEFINED
3205       index = fieldFromInstruction32(Insn, 7, 1);
3206       if (fieldFromInstruction32(Insn, 4, 2) != 0)
3207         align = 4;
3208   }
3209 
3210   if (Rm != 0xF) { // Writeback
3211     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3212     return MCDisassembler::Fail;
3213   }
3214   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3215     return MCDisassembler::Fail;
3216   Inst.addOperand(MCOperand::CreateImm(align));
3217   if (Rm != 0xF) {
3218     if (Rm != 0xD) {
3219       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3220     return MCDisassembler::Fail;
3221     } else
3222       Inst.addOperand(MCOperand::CreateReg(0));
3223   }
3224 
3225   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3226     return MCDisassembler::Fail;
3227   Inst.addOperand(MCOperand::CreateImm(index));
3228 
3229   return S;
3230 }
3231 
3232 
3233 static DecodeStatus DecodeVLD2LN(llvm::MCInst &Inst, unsigned Insn,
3234                          uint64_t Address, const void *Decoder) {
3235   DecodeStatus S = MCDisassembler::Success;
3236 
3237   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3238   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3239   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3240   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3241   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3242 
3243   unsigned align = 0;
3244   unsigned index = 0;
3245   unsigned inc = 1;
3246   switch (size) {
3247     default:
3248       return MCDisassembler::Fail;
3249     case 0:
3250       index = fieldFromInstruction32(Insn, 5, 3);
3251       if (fieldFromInstruction32(Insn, 4, 1))
3252         align = 2;
3253       break;
3254     case 1:
3255       index = fieldFromInstruction32(Insn, 6, 2);
3256       if (fieldFromInstruction32(Insn, 4, 1))
3257         align = 4;
3258       if (fieldFromInstruction32(Insn, 5, 1))
3259         inc = 2;
3260       break;
3261     case 2:
3262       if (fieldFromInstruction32(Insn, 5, 1))
3263         return MCDisassembler::Fail; // UNDEFINED
3264       index = fieldFromInstruction32(Insn, 7, 1);
3265       if (fieldFromInstruction32(Insn, 4, 1) != 0)
3266         align = 8;
3267       if (fieldFromInstruction32(Insn, 6, 1))
3268         inc = 2;
3269       break;
3270   }
3271 
3272   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3273     return MCDisassembler::Fail;
3274   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3275     return MCDisassembler::Fail;
3276   if (Rm != 0xF) { // Writeback
3277     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3278       return MCDisassembler::Fail;
3279   }
3280   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3281     return MCDisassembler::Fail;
3282   Inst.addOperand(MCOperand::CreateImm(align));
3283   if (Rm != 0xF) {
3284     if (Rm != 0xD) {
3285       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3286         return MCDisassembler::Fail;
3287     } else
3288       Inst.addOperand(MCOperand::CreateReg(0));
3289   }
3290 
3291   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3292     return MCDisassembler::Fail;
3293   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3294     return MCDisassembler::Fail;
3295   Inst.addOperand(MCOperand::CreateImm(index));
3296 
3297   return S;
3298 }
3299 
3300 static DecodeStatus DecodeVST2LN(llvm::MCInst &Inst, unsigned Insn,
3301                          uint64_t Address, const void *Decoder) {
3302   DecodeStatus S = MCDisassembler::Success;
3303 
3304   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3305   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3306   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3307   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3308   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3309 
3310   unsigned align = 0;
3311   unsigned index = 0;
3312   unsigned inc = 1;
3313   switch (size) {
3314     default:
3315       return MCDisassembler::Fail;
3316     case 0:
3317       index = fieldFromInstruction32(Insn, 5, 3);
3318       if (fieldFromInstruction32(Insn, 4, 1))
3319         align = 2;
3320       break;
3321     case 1:
3322       index = fieldFromInstruction32(Insn, 6, 2);
3323       if (fieldFromInstruction32(Insn, 4, 1))
3324         align = 4;
3325       if (fieldFromInstruction32(Insn, 5, 1))
3326         inc = 2;
3327       break;
3328     case 2:
3329       if (fieldFromInstruction32(Insn, 5, 1))
3330         return MCDisassembler::Fail; // UNDEFINED
3331       index = fieldFromInstruction32(Insn, 7, 1);
3332       if (fieldFromInstruction32(Insn, 4, 1) != 0)
3333         align = 8;
3334       if (fieldFromInstruction32(Insn, 6, 1))
3335         inc = 2;
3336       break;
3337   }
3338 
3339   if (Rm != 0xF) { // Writeback
3340     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3341       return MCDisassembler::Fail;
3342   }
3343   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3344     return MCDisassembler::Fail;
3345   Inst.addOperand(MCOperand::CreateImm(align));
3346   if (Rm != 0xF) {
3347     if (Rm != 0xD) {
3348       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3349         return MCDisassembler::Fail;
3350     } else
3351       Inst.addOperand(MCOperand::CreateReg(0));
3352   }
3353 
3354   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3355     return MCDisassembler::Fail;
3356   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3357     return MCDisassembler::Fail;
3358   Inst.addOperand(MCOperand::CreateImm(index));
3359 
3360   return S;
3361 }
3362 
3363 
3364 static DecodeStatus DecodeVLD3LN(llvm::MCInst &Inst, unsigned Insn,
3365                          uint64_t Address, const void *Decoder) {
3366   DecodeStatus S = MCDisassembler::Success;
3367 
3368   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3369   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3370   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3371   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3372   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3373 
3374   unsigned align = 0;
3375   unsigned index = 0;
3376   unsigned inc = 1;
3377   switch (size) {
3378     default:
3379       return MCDisassembler::Fail;
3380     case 0:
3381       if (fieldFromInstruction32(Insn, 4, 1))
3382         return MCDisassembler::Fail; // UNDEFINED
3383       index = fieldFromInstruction32(Insn, 5, 3);
3384       break;
3385     case 1:
3386       if (fieldFromInstruction32(Insn, 4, 1))
3387         return MCDisassembler::Fail; // UNDEFINED
3388       index = fieldFromInstruction32(Insn, 6, 2);
3389       if (fieldFromInstruction32(Insn, 5, 1))
3390         inc = 2;
3391       break;
3392     case 2:
3393       if (fieldFromInstruction32(Insn, 4, 2))
3394         return MCDisassembler::Fail; // UNDEFINED
3395       index = fieldFromInstruction32(Insn, 7, 1);
3396       if (fieldFromInstruction32(Insn, 6, 1))
3397         inc = 2;
3398       break;
3399   }
3400 
3401   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3402     return MCDisassembler::Fail;
3403   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3404     return MCDisassembler::Fail;
3405   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3406     return MCDisassembler::Fail;
3407 
3408   if (Rm != 0xF) { // Writeback
3409     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3410     return MCDisassembler::Fail;
3411   }
3412   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3413     return MCDisassembler::Fail;
3414   Inst.addOperand(MCOperand::CreateImm(align));
3415   if (Rm != 0xF) {
3416     if (Rm != 0xD) {
3417       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3418     return MCDisassembler::Fail;
3419     } else
3420       Inst.addOperand(MCOperand::CreateReg(0));
3421   }
3422 
3423   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3424     return MCDisassembler::Fail;
3425   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3426     return MCDisassembler::Fail;
3427   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3428     return MCDisassembler::Fail;
3429   Inst.addOperand(MCOperand::CreateImm(index));
3430 
3431   return S;
3432 }
3433 
3434 static DecodeStatus DecodeVST3LN(llvm::MCInst &Inst, unsigned Insn,
3435                          uint64_t Address, const void *Decoder) {
3436   DecodeStatus S = MCDisassembler::Success;
3437 
3438   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3439   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3440   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3441   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3442   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3443 
3444   unsigned align = 0;
3445   unsigned index = 0;
3446   unsigned inc = 1;
3447   switch (size) {
3448     default:
3449       return MCDisassembler::Fail;
3450     case 0:
3451       if (fieldFromInstruction32(Insn, 4, 1))
3452         return MCDisassembler::Fail; // UNDEFINED
3453       index = fieldFromInstruction32(Insn, 5, 3);
3454       break;
3455     case 1:
3456       if (fieldFromInstruction32(Insn, 4, 1))
3457         return MCDisassembler::Fail; // UNDEFINED
3458       index = fieldFromInstruction32(Insn, 6, 2);
3459       if (fieldFromInstruction32(Insn, 5, 1))
3460         inc = 2;
3461       break;
3462     case 2:
3463       if (fieldFromInstruction32(Insn, 4, 2))
3464         return MCDisassembler::Fail; // UNDEFINED
3465       index = fieldFromInstruction32(Insn, 7, 1);
3466       if (fieldFromInstruction32(Insn, 6, 1))
3467         inc = 2;
3468       break;
3469   }
3470 
3471   if (Rm != 0xF) { // Writeback
3472     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3473     return MCDisassembler::Fail;
3474   }
3475   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3476     return MCDisassembler::Fail;
3477   Inst.addOperand(MCOperand::CreateImm(align));
3478   if (Rm != 0xF) {
3479     if (Rm != 0xD) {
3480       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3481     return MCDisassembler::Fail;
3482     } else
3483       Inst.addOperand(MCOperand::CreateReg(0));
3484   }
3485 
3486   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3487     return MCDisassembler::Fail;
3488   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3489     return MCDisassembler::Fail;
3490   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3491     return MCDisassembler::Fail;
3492   Inst.addOperand(MCOperand::CreateImm(index));
3493 
3494   return S;
3495 }
3496 
3497 
3498 static DecodeStatus DecodeVLD4LN(llvm::MCInst &Inst, unsigned Insn,
3499                          uint64_t Address, const void *Decoder) {
3500   DecodeStatus S = MCDisassembler::Success;
3501 
3502   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3503   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3504   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3505   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3506   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3507 
3508   unsigned align = 0;
3509   unsigned index = 0;
3510   unsigned inc = 1;
3511   switch (size) {
3512     default:
3513       return MCDisassembler::Fail;
3514     case 0:
3515       if (fieldFromInstruction32(Insn, 4, 1))
3516         align = 4;
3517       index = fieldFromInstruction32(Insn, 5, 3);
3518       break;
3519     case 1:
3520       if (fieldFromInstruction32(Insn, 4, 1))
3521         align = 8;
3522       index = fieldFromInstruction32(Insn, 6, 2);
3523       if (fieldFromInstruction32(Insn, 5, 1))
3524         inc = 2;
3525       break;
3526     case 2:
3527       if (fieldFromInstruction32(Insn, 4, 2))
3528         align = 4 << fieldFromInstruction32(Insn, 4, 2);
3529       index = fieldFromInstruction32(Insn, 7, 1);
3530       if (fieldFromInstruction32(Insn, 6, 1))
3531         inc = 2;
3532       break;
3533   }
3534 
3535   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3536     return MCDisassembler::Fail;
3537   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3538     return MCDisassembler::Fail;
3539   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3540     return MCDisassembler::Fail;
3541   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
3542     return MCDisassembler::Fail;
3543 
3544   if (Rm != 0xF) { // Writeback
3545     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3546       return MCDisassembler::Fail;
3547   }
3548   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3549     return MCDisassembler::Fail;
3550   Inst.addOperand(MCOperand::CreateImm(align));
3551   if (Rm != 0xF) {
3552     if (Rm != 0xD) {
3553       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3554         return MCDisassembler::Fail;
3555     } else
3556       Inst.addOperand(MCOperand::CreateReg(0));
3557   }
3558 
3559   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3560     return MCDisassembler::Fail;
3561   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3562     return MCDisassembler::Fail;
3563   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3564     return MCDisassembler::Fail;
3565   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
3566     return MCDisassembler::Fail;
3567   Inst.addOperand(MCOperand::CreateImm(index));
3568 
3569   return S;
3570 }
3571 
3572 static DecodeStatus DecodeVST4LN(llvm::MCInst &Inst, unsigned Insn,
3573                          uint64_t Address, const void *Decoder) {
3574   DecodeStatus S = MCDisassembler::Success;
3575 
3576   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3577   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3578   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3579   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3580   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3581 
3582   unsigned align = 0;
3583   unsigned index = 0;
3584   unsigned inc = 1;
3585   switch (size) {
3586     default:
3587       return MCDisassembler::Fail;
3588     case 0:
3589       if (fieldFromInstruction32(Insn, 4, 1))
3590         align = 4;
3591       index = fieldFromInstruction32(Insn, 5, 3);
3592       break;
3593     case 1:
3594       if (fieldFromInstruction32(Insn, 4, 1))
3595         align = 8;
3596       index = fieldFromInstruction32(Insn, 6, 2);
3597       if (fieldFromInstruction32(Insn, 5, 1))
3598         inc = 2;
3599       break;
3600     case 2:
3601       if (fieldFromInstruction32(Insn, 4, 2))
3602         align = 4 << fieldFromInstruction32(Insn, 4, 2);
3603       index = fieldFromInstruction32(Insn, 7, 1);
3604       if (fieldFromInstruction32(Insn, 6, 1))
3605         inc = 2;
3606       break;
3607   }
3608 
3609   if (Rm != 0xF) { // Writeback
3610     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3611     return MCDisassembler::Fail;
3612   }
3613   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3614     return MCDisassembler::Fail;
3615   Inst.addOperand(MCOperand::CreateImm(align));
3616   if (Rm != 0xF) {
3617     if (Rm != 0xD) {
3618       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3619     return MCDisassembler::Fail;
3620     } else
3621       Inst.addOperand(MCOperand::CreateReg(0));
3622   }
3623 
3624   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3625     return MCDisassembler::Fail;
3626   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3627     return MCDisassembler::Fail;
3628   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3629     return MCDisassembler::Fail;
3630   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
3631     return MCDisassembler::Fail;
3632   Inst.addOperand(MCOperand::CreateImm(index));
3633 
3634   return S;
3635 }
3636 
3637 static DecodeStatus DecodeVMOVSRR(llvm::MCInst &Inst, unsigned Insn,
3638                                   uint64_t Address, const void *Decoder) {
3639   DecodeStatus S = MCDisassembler::Success;
3640   unsigned Rt  = fieldFromInstruction32(Insn, 12, 4);
3641   unsigned Rt2 = fieldFromInstruction32(Insn, 16, 4);
3642   unsigned Rm  = fieldFromInstruction32(Insn,  0, 4);
3643   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3644   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
3645 
3646   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
3647     S = MCDisassembler::SoftFail;
3648 
3649   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
3650     return MCDisassembler::Fail;
3651   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
3652     return MCDisassembler::Fail;
3653   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
3654     return MCDisassembler::Fail;
3655   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
3656     return MCDisassembler::Fail;
3657   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3658     return MCDisassembler::Fail;
3659 
3660   return S;
3661 }
3662 
3663 static DecodeStatus DecodeVMOVRRS(llvm::MCInst &Inst, unsigned Insn,
3664                                   uint64_t Address, const void *Decoder) {
3665   DecodeStatus S = MCDisassembler::Success;
3666   unsigned Rt  = fieldFromInstruction32(Insn, 12, 4);
3667   unsigned Rt2 = fieldFromInstruction32(Insn, 16, 4);
3668   unsigned Rm  = fieldFromInstruction32(Insn,  0, 4);
3669   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3670   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
3671 
3672   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
3673     S = MCDisassembler::SoftFail;
3674 
3675   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
3676     return MCDisassembler::Fail;
3677   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
3678     return MCDisassembler::Fail;
3679   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
3680     return MCDisassembler::Fail;
3681   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
3682     return MCDisassembler::Fail;
3683   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3684     return MCDisassembler::Fail;
3685 
3686   return S;
3687 }
3688 
3689 static DecodeStatus DecodeIT(llvm::MCInst &Inst, unsigned Insn,
3690                              uint64_t Address, const void *Decoder) {
3691   DecodeStatus S = MCDisassembler::Success;
3692   unsigned pred = fieldFromInstruction16(Insn, 4, 4);
3693   // The InstPrinter needs to have the low bit of the predicate in
3694   // the mask operand to be able to print it properly.
3695   unsigned mask = fieldFromInstruction16(Insn, 0, 5);
3696 
3697   if (pred == 0xF) {
3698     pred = 0xE;
3699     S = MCDisassembler::SoftFail;
3700   }
3701 
3702   if ((mask & 0xF) == 0) {
3703     // Preserve the high bit of the mask, which is the low bit of
3704     // the predicate.
3705     mask &= 0x10;
3706     mask |= 0x8;
3707     S = MCDisassembler::SoftFail;
3708   }
3709 
3710   Inst.addOperand(MCOperand::CreateImm(pred));
3711   Inst.addOperand(MCOperand::CreateImm(mask));
3712   return S;
3713 }
3714 
3715 static DecodeStatus
3716 DecodeT2LDRDPreInstruction(llvm::MCInst &Inst, unsigned Insn,
3717                            uint64_t Address, const void *Decoder) {
3718   DecodeStatus S = MCDisassembler::Success;
3719 
3720   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3721   unsigned Rt2 = fieldFromInstruction32(Insn, 8, 4);
3722   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3723   unsigned addr = fieldFromInstruction32(Insn, 0, 8);
3724   unsigned W = fieldFromInstruction32(Insn, 21, 1);
3725   unsigned U = fieldFromInstruction32(Insn, 23, 1);
3726   unsigned P = fieldFromInstruction32(Insn, 24, 1);
3727   bool writeback = (W == 1) | (P == 0);
3728 
3729   addr |= (U << 8) | (Rn << 9);
3730 
3731   if (writeback && (Rn == Rt || Rn == Rt2))
3732     Check(S, MCDisassembler::SoftFail);
3733   if (Rt == Rt2)
3734     Check(S, MCDisassembler::SoftFail);
3735 
3736   // Rt
3737   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
3738     return MCDisassembler::Fail;
3739   // Rt2
3740   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
3741     return MCDisassembler::Fail;
3742   // Writeback operand
3743   if (!Check(S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
3744     return MCDisassembler::Fail;
3745   // addr
3746   if (!Check(S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
3747     return MCDisassembler::Fail;
3748 
3749   return S;
3750 }
3751 
3752 static DecodeStatus
3753 DecodeT2STRDPreInstruction(llvm::MCInst &Inst, unsigned Insn,
3754                            uint64_t Address, const void *Decoder) {
3755   DecodeStatus S = MCDisassembler::Success;
3756 
3757   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3758   unsigned Rt2 = fieldFromInstruction32(Insn, 8, 4);
3759   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3760   unsigned addr = fieldFromInstruction32(Insn, 0, 8);
3761   unsigned W = fieldFromInstruction32(Insn, 21, 1);
3762   unsigned U = fieldFromInstruction32(Insn, 23, 1);
3763   unsigned P = fieldFromInstruction32(Insn, 24, 1);
3764   bool writeback = (W == 1) | (P == 0);
3765 
3766   addr |= (U << 8) | (Rn << 9);
3767 
3768   if (writeback && (Rn == Rt || Rn == Rt2))
3769     Check(S, MCDisassembler::SoftFail);
3770 
3771   // Writeback operand
3772   if (!Check(S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
3773     return MCDisassembler::Fail;
3774   // Rt
3775   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
3776     return MCDisassembler::Fail;
3777   // Rt2
3778   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
3779     return MCDisassembler::Fail;
3780   // addr
3781   if (!Check(S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
3782     return MCDisassembler::Fail;
3783 
3784   return S;
3785 }
3786 
3787 static DecodeStatus DecodeT2Adr(llvm::MCInst &Inst, uint32_t Insn,
3788                                 uint64_t Address, const void *Decoder) {
3789   unsigned sign1 = fieldFromInstruction32(Insn, 21, 1);
3790   unsigned sign2 = fieldFromInstruction32(Insn, 23, 1);
3791   if (sign1 != sign2) return MCDisassembler::Fail;
3792 
3793   unsigned Val = fieldFromInstruction32(Insn, 0, 8);
3794   Val |= fieldFromInstruction32(Insn, 12, 3) << 8;
3795   Val |= fieldFromInstruction32(Insn, 26, 1) << 11;
3796   Val |= sign1 << 12;
3797   Inst.addOperand(MCOperand::CreateImm(SignExtend32<13>(Val)));
3798 
3799   return MCDisassembler::Success;
3800 }
3801 
3802