xref: /llvm-project/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp (revision 33d39536e6a5a61eb651beab997819566e031273)
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 DecodeT2Imm8(llvm::MCInst &Inst, unsigned Val,
273                                uint64_t Address, const void *Decoder);
274 static DecodeStatus DecodeT2AddrModeImm8(llvm::MCInst &Inst, unsigned Val,
275                                uint64_t Address, const void *Decoder);
276 static DecodeStatus DecodeThumbAddSPImm(llvm::MCInst &Inst, uint16_t Val,
277                                uint64_t Address, const void *Decoder);
278 static DecodeStatus DecodeThumbAddSPReg(llvm::MCInst &Inst, uint16_t Insn,
279                                 uint64_t Address, const void *Decoder);
280 static DecodeStatus DecodeThumbCPS(llvm::MCInst &Inst, uint16_t Insn,
281                                 uint64_t Address, const void *Decoder);
282 static DecodeStatus DecodeThumbBLXOffset(llvm::MCInst &Inst, unsigned Insn,
283                                 uint64_t Address, const void *Decoder);
284 static DecodeStatus DecodeT2AddrModeImm12(llvm::MCInst &Inst, unsigned Val,
285                                 uint64_t Address, const void *Decoder);
286 static DecodeStatus DecodeThumb2BCCInstruction(llvm::MCInst &Inst, unsigned Val,
287                                 uint64_t Address, const void *Decoder);
288 static DecodeStatus DecodeT2SOImm(llvm::MCInst &Inst, unsigned Val,
289                                 uint64_t Address, const void *Decoder);
290 static DecodeStatus DecodeThumbBCCTargetOperand(llvm::MCInst &Inst,unsigned Val,
291                                 uint64_t Address, const void *Decoder);
292 static DecodeStatus DecodeThumbBLTargetOperand(llvm::MCInst &Inst, unsigned Val,
293                                 uint64_t Address, const void *Decoder);
294 static DecodeStatus DecodeIT(llvm::MCInst &Inst, unsigned Val,
295                                 uint64_t Address, const void *Decoder);
296 static DecodeStatus DecodeT2LDRDPreInstruction(llvm::MCInst &Inst,unsigned Insn,
297                                uint64_t Address, const void *Decoder);
298 static DecodeStatus DecodeT2STRDPreInstruction(llvm::MCInst &Inst,unsigned Insn,
299                                uint64_t Address, const void *Decoder);
300 
301 #include "ARMGenDisassemblerTables.inc"
302 #include "ARMGenInstrInfo.inc"
303 #include "ARMGenEDInfo.inc"
304 
305 static MCDisassembler *createARMDisassembler(const Target &T, const MCSubtargetInfo &STI) {
306   return new ARMDisassembler(STI);
307 }
308 
309 static MCDisassembler *createThumbDisassembler(const Target &T, const MCSubtargetInfo &STI) {
310   return new ThumbDisassembler(STI);
311 }
312 
313 EDInstInfo *ARMDisassembler::getEDInfo() const {
314   return instInfoARM;
315 }
316 
317 EDInstInfo *ThumbDisassembler::getEDInfo() const {
318   return instInfoARM;
319 }
320 
321 DecodeStatus ARMDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
322                                              const MemoryObject &Region,
323                                              uint64_t Address,
324                                              raw_ostream &os) const {
325   uint8_t bytes[4];
326 
327   assert(!(STI.getFeatureBits() & ARM::ModeThumb) &&
328          "Asked to disassemble an ARM instruction but Subtarget is in Thumb mode!");
329 
330   // We want to read exactly 4 bytes of data.
331   if (Region.readBytes(Address, 4, (uint8_t*)bytes, NULL) == -1) {
332     Size = 0;
333     return MCDisassembler::Fail;
334   }
335 
336   // Encoded as a small-endian 32-bit word in the stream.
337   uint32_t insn = (bytes[3] << 24) |
338                   (bytes[2] << 16) |
339                   (bytes[1] <<  8) |
340                   (bytes[0] <<  0);
341 
342   // Calling the auto-generated decoder function.
343   DecodeStatus result = decodeARMInstruction32(MI, insn, Address, this, STI);
344   if (result != MCDisassembler::Fail) {
345     Size = 4;
346     return result;
347   }
348 
349   // VFP and NEON instructions, similarly, are shared between ARM
350   // and Thumb modes.
351   MI.clear();
352   result = decodeVFPInstruction32(MI, insn, Address, this, STI);
353   if (result != MCDisassembler::Fail) {
354     Size = 4;
355     return result;
356   }
357 
358   MI.clear();
359   result = decodeNEONDataInstruction32(MI, insn, Address, this, STI);
360   if (result != MCDisassembler::Fail) {
361     Size = 4;
362     // Add a fake predicate operand, because we share these instruction
363     // definitions with Thumb2 where these instructions are predicable.
364     if (!DecodePredicateOperand(MI, 0xE, Address, this))
365       return MCDisassembler::Fail;
366     return result;
367   }
368 
369   MI.clear();
370   result = decodeNEONLoadStoreInstruction32(MI, insn, Address, this, STI);
371   if (result != MCDisassembler::Fail) {
372     Size = 4;
373     // Add a fake predicate operand, because we share these instruction
374     // definitions with Thumb2 where these instructions are predicable.
375     if (!DecodePredicateOperand(MI, 0xE, Address, this))
376       return MCDisassembler::Fail;
377     return result;
378   }
379 
380   MI.clear();
381   result = decodeNEONDupInstruction32(MI, insn, Address, this, STI);
382   if (result != MCDisassembler::Fail) {
383     Size = 4;
384     // Add a fake predicate operand, because we share these instruction
385     // definitions with Thumb2 where these instructions are predicable.
386     if (!DecodePredicateOperand(MI, 0xE, Address, this))
387       return MCDisassembler::Fail;
388     return result;
389   }
390 
391   MI.clear();
392 
393   Size = 0;
394   return MCDisassembler::Fail;
395 }
396 
397 namespace llvm {
398 extern MCInstrDesc ARMInsts[];
399 }
400 
401 // Thumb1 instructions don't have explicit S bits.  Rather, they
402 // implicitly set CPSR.  Since it's not represented in the encoding, the
403 // auto-generated decoder won't inject the CPSR operand.  We need to fix
404 // that as a post-pass.
405 static void AddThumb1SBit(MCInst &MI, bool InITBlock) {
406   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
407   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
408   MCInst::iterator I = MI.begin();
409   for (unsigned i = 0; i < NumOps; ++i, ++I) {
410     if (I == MI.end()) break;
411     if (OpInfo[i].isOptionalDef() && OpInfo[i].RegClass == ARM::CCRRegClassID) {
412       if (i > 0 && OpInfo[i-1].isPredicate()) continue;
413       MI.insert(I, MCOperand::CreateReg(InITBlock ? 0 : ARM::CPSR));
414       return;
415     }
416   }
417 
418   MI.insert(I, MCOperand::CreateReg(InITBlock ? 0 : ARM::CPSR));
419 }
420 
421 // Most Thumb instructions don't have explicit predicates in the
422 // encoding, but rather get their predicates from IT context.  We need
423 // to fix up the predicate operands using this context information as a
424 // post-pass.
425 MCDisassembler::DecodeStatus
426 ThumbDisassembler::AddThumbPredicate(MCInst &MI) const {
427   // A few instructions actually have predicates encoded in them.  Don't
428   // try to overwrite it if we're seeing one of those.
429   switch (MI.getOpcode()) {
430     case ARM::tBcc:
431     case ARM::t2Bcc:
432     case ARM::tCBZ:
433     case ARM::tCBNZ:
434       // Some instructions (mostly conditional branches) are not
435       // allowed in IT blocks.
436       if (!ITBlock.empty())
437         return SoftFail;
438       return Success;
439       break;
440     default:
441       break;
442   }
443 
444   // If we're in an IT block, base the predicate on that.  Otherwise,
445   // assume a predicate of AL.
446   unsigned CC;
447   if (!ITBlock.empty()) {
448     CC = ITBlock.back();
449     if (CC == 0xF)
450       CC = ARMCC::AL;
451     ITBlock.pop_back();
452   } else
453     CC = ARMCC::AL;
454 
455   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
456   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
457   MCInst::iterator I = MI.begin();
458   for (unsigned i = 0; i < NumOps; ++i, ++I) {
459     if (I == MI.end()) break;
460     if (OpInfo[i].isPredicate()) {
461       I = MI.insert(I, MCOperand::CreateImm(CC));
462       ++I;
463       if (CC == ARMCC::AL)
464         MI.insert(I, MCOperand::CreateReg(0));
465       else
466         MI.insert(I, MCOperand::CreateReg(ARM::CPSR));
467       return Success;
468     }
469   }
470 
471   I = MI.insert(I, MCOperand::CreateImm(CC));
472   ++I;
473   if (CC == ARMCC::AL)
474     MI.insert(I, MCOperand::CreateReg(0));
475   else
476     MI.insert(I, MCOperand::CreateReg(ARM::CPSR));
477 
478   return Success;
479 }
480 
481 // Thumb VFP instructions are a special case.  Because we share their
482 // encodings between ARM and Thumb modes, and they are predicable in ARM
483 // mode, the auto-generated decoder will give them an (incorrect)
484 // predicate operand.  We need to rewrite these operands based on the IT
485 // context as a post-pass.
486 void ThumbDisassembler::UpdateThumbVFPPredicate(MCInst &MI) const {
487   unsigned CC;
488   if (!ITBlock.empty()) {
489     CC = ITBlock.back();
490     ITBlock.pop_back();
491   } else
492     CC = ARMCC::AL;
493 
494   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
495   MCInst::iterator I = MI.begin();
496   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
497   for (unsigned i = 0; i < NumOps; ++i, ++I) {
498     if (OpInfo[i].isPredicate() ) {
499       I->setImm(CC);
500       ++I;
501       if (CC == ARMCC::AL)
502         I->setReg(0);
503       else
504         I->setReg(ARM::CPSR);
505       return;
506     }
507   }
508 }
509 
510 DecodeStatus ThumbDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
511                                                const MemoryObject &Region,
512                                                uint64_t Address,
513                                                raw_ostream &os) const {
514   uint8_t bytes[4];
515 
516   assert((STI.getFeatureBits() & ARM::ModeThumb) &&
517          "Asked to disassemble in Thumb mode but Subtarget is in ARM mode!");
518 
519   // We want to read exactly 2 bytes of data.
520   if (Region.readBytes(Address, 2, (uint8_t*)bytes, NULL) == -1) {
521     Size = 0;
522     return MCDisassembler::Fail;
523   }
524 
525   uint16_t insn16 = (bytes[1] << 8) | bytes[0];
526   DecodeStatus result = decodeThumbInstruction16(MI, insn16, Address, this, STI);
527   if (result != MCDisassembler::Fail) {
528     Size = 2;
529     Check(result, AddThumbPredicate(MI));
530     return result;
531   }
532 
533   MI.clear();
534   result = decodeThumbSBitInstruction16(MI, insn16, Address, this, STI);
535   if (result) {
536     Size = 2;
537     bool InITBlock = !ITBlock.empty();
538     Check(result, AddThumbPredicate(MI));
539     AddThumb1SBit(MI, InITBlock);
540     return result;
541   }
542 
543   MI.clear();
544   result = decodeThumb2Instruction16(MI, insn16, Address, this, STI);
545   if (result != MCDisassembler::Fail) {
546     Size = 2;
547     Check(result, AddThumbPredicate(MI));
548 
549     // If we find an IT instruction, we need to parse its condition
550     // code and mask operands so that we can apply them correctly
551     // to the subsequent instructions.
552     if (MI.getOpcode() == ARM::t2IT) {
553       // (3 - the number of trailing zeros) is the number of then / else.
554       unsigned firstcond = MI.getOperand(0).getImm();
555       unsigned Mask = MI.getOperand(1).getImm();
556       unsigned CondBit0 = Mask >> 4 & 1;
557       unsigned NumTZ = CountTrailingZeros_32(Mask);
558       assert(NumTZ <= 3 && "Invalid IT mask!");
559       for (unsigned Pos = 3, e = NumTZ; Pos > e; --Pos) {
560         bool T = ((Mask >> Pos) & 1) == CondBit0;
561         if (T)
562           ITBlock.insert(ITBlock.begin(), firstcond);
563         else
564           ITBlock.insert(ITBlock.begin(), firstcond ^ 1);
565       }
566 
567       ITBlock.push_back(firstcond);
568     }
569 
570     return result;
571   }
572 
573   // We want to read exactly 4 bytes of data.
574   if (Region.readBytes(Address, 4, (uint8_t*)bytes, NULL) == -1) {
575     Size = 0;
576     return MCDisassembler::Fail;
577   }
578 
579   uint32_t insn32 = (bytes[3] <<  8) |
580                     (bytes[2] <<  0) |
581                     (bytes[1] << 24) |
582                     (bytes[0] << 16);
583   MI.clear();
584   result = decodeThumbInstruction32(MI, insn32, Address, this, STI);
585   if (result != MCDisassembler::Fail) {
586     Size = 4;
587     bool InITBlock = ITBlock.size();
588     Check(result, AddThumbPredicate(MI));
589     AddThumb1SBit(MI, InITBlock);
590     return result;
591   }
592 
593   MI.clear();
594   result = decodeThumb2Instruction32(MI, insn32, Address, this, STI);
595   if (result != MCDisassembler::Fail) {
596     Size = 4;
597     Check(result, AddThumbPredicate(MI));
598     return result;
599   }
600 
601   MI.clear();
602   result = decodeVFPInstruction32(MI, insn32, Address, this, STI);
603   if (result != MCDisassembler::Fail) {
604     Size = 4;
605     UpdateThumbVFPPredicate(MI);
606     return result;
607   }
608 
609   MI.clear();
610   result = decodeNEONDupInstruction32(MI, insn32, Address, this, STI);
611   if (result != MCDisassembler::Fail) {
612     Size = 4;
613     Check(result, AddThumbPredicate(MI));
614     return result;
615   }
616 
617   if (fieldFromInstruction32(insn32, 24, 8) == 0xF9) {
618     MI.clear();
619     uint32_t NEONLdStInsn = insn32;
620     NEONLdStInsn &= 0xF0FFFFFF;
621     NEONLdStInsn |= 0x04000000;
622     result = decodeNEONLoadStoreInstruction32(MI, NEONLdStInsn, Address, this, STI);
623     if (result != MCDisassembler::Fail) {
624       Size = 4;
625       Check(result, AddThumbPredicate(MI));
626       return result;
627     }
628   }
629 
630   if (fieldFromInstruction32(insn32, 24, 4) == 0xF) {
631     MI.clear();
632     uint32_t NEONDataInsn = insn32;
633     NEONDataInsn &= 0xF0FFFFFF; // Clear bits 27-24
634     NEONDataInsn |= (NEONDataInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
635     NEONDataInsn |= 0x12000000; // Set bits 28 and 25
636     result = decodeNEONDataInstruction32(MI, NEONDataInsn, Address, this, STI);
637     if (result != MCDisassembler::Fail) {
638       Size = 4;
639       Check(result, AddThumbPredicate(MI));
640       return result;
641     }
642   }
643 
644   Size = 0;
645   return MCDisassembler::Fail;
646 }
647 
648 
649 extern "C" void LLVMInitializeARMDisassembler() {
650   TargetRegistry::RegisterMCDisassembler(TheARMTarget,
651                                          createARMDisassembler);
652   TargetRegistry::RegisterMCDisassembler(TheThumbTarget,
653                                          createThumbDisassembler);
654 }
655 
656 static const unsigned GPRDecoderTable[] = {
657   ARM::R0, ARM::R1, ARM::R2, ARM::R3,
658   ARM::R4, ARM::R5, ARM::R6, ARM::R7,
659   ARM::R8, ARM::R9, ARM::R10, ARM::R11,
660   ARM::R12, ARM::SP, ARM::LR, ARM::PC
661 };
662 
663 static DecodeStatus DecodeGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
664                                    uint64_t Address, const void *Decoder) {
665   if (RegNo > 15)
666     return MCDisassembler::Fail;
667 
668   unsigned Register = GPRDecoderTable[RegNo];
669   Inst.addOperand(MCOperand::CreateReg(Register));
670   return MCDisassembler::Success;
671 }
672 
673 static DecodeStatus
674 DecodeGPRnopcRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
675                            uint64_t Address, const void *Decoder) {
676   if (RegNo == 15) return MCDisassembler::Fail;
677   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
678 }
679 
680 static DecodeStatus DecodetGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
681                                    uint64_t Address, const void *Decoder) {
682   if (RegNo > 7)
683     return MCDisassembler::Fail;
684   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
685 }
686 
687 static DecodeStatus DecodetcGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
688                                    uint64_t Address, const void *Decoder) {
689   unsigned Register = 0;
690   switch (RegNo) {
691     case 0:
692       Register = ARM::R0;
693       break;
694     case 1:
695       Register = ARM::R1;
696       break;
697     case 2:
698       Register = ARM::R2;
699       break;
700     case 3:
701       Register = ARM::R3;
702       break;
703     case 9:
704       Register = ARM::R9;
705       break;
706     case 12:
707       Register = ARM::R12;
708       break;
709     default:
710       return MCDisassembler::Fail;
711     }
712 
713   Inst.addOperand(MCOperand::CreateReg(Register));
714   return MCDisassembler::Success;
715 }
716 
717 static DecodeStatus DecoderGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
718                                    uint64_t Address, const void *Decoder) {
719   if (RegNo == 13 || RegNo == 15) return MCDisassembler::Fail;
720   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
721 }
722 
723 static const unsigned SPRDecoderTable[] = {
724      ARM::S0,  ARM::S1,  ARM::S2,  ARM::S3,
725      ARM::S4,  ARM::S5,  ARM::S6,  ARM::S7,
726      ARM::S8,  ARM::S9, ARM::S10, ARM::S11,
727     ARM::S12, ARM::S13, ARM::S14, ARM::S15,
728     ARM::S16, ARM::S17, ARM::S18, ARM::S19,
729     ARM::S20, ARM::S21, ARM::S22, ARM::S23,
730     ARM::S24, ARM::S25, ARM::S26, ARM::S27,
731     ARM::S28, ARM::S29, ARM::S30, ARM::S31
732 };
733 
734 static DecodeStatus DecodeSPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
735                                    uint64_t Address, const void *Decoder) {
736   if (RegNo > 31)
737     return MCDisassembler::Fail;
738 
739   unsigned Register = SPRDecoderTable[RegNo];
740   Inst.addOperand(MCOperand::CreateReg(Register));
741   return MCDisassembler::Success;
742 }
743 
744 static const unsigned DPRDecoderTable[] = {
745      ARM::D0,  ARM::D1,  ARM::D2,  ARM::D3,
746      ARM::D4,  ARM::D5,  ARM::D6,  ARM::D7,
747      ARM::D8,  ARM::D9, ARM::D10, ARM::D11,
748     ARM::D12, ARM::D13, ARM::D14, ARM::D15,
749     ARM::D16, ARM::D17, ARM::D18, ARM::D19,
750     ARM::D20, ARM::D21, ARM::D22, ARM::D23,
751     ARM::D24, ARM::D25, ARM::D26, ARM::D27,
752     ARM::D28, ARM::D29, ARM::D30, ARM::D31
753 };
754 
755 static DecodeStatus DecodeDPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
756                                    uint64_t Address, const void *Decoder) {
757   if (RegNo > 31)
758     return MCDisassembler::Fail;
759 
760   unsigned Register = DPRDecoderTable[RegNo];
761   Inst.addOperand(MCOperand::CreateReg(Register));
762   return MCDisassembler::Success;
763 }
764 
765 static DecodeStatus DecodeDPR_8RegisterClass(llvm::MCInst &Inst, unsigned RegNo,
766                                    uint64_t Address, const void *Decoder) {
767   if (RegNo > 7)
768     return MCDisassembler::Fail;
769   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
770 }
771 
772 static DecodeStatus
773 DecodeDPR_VFP2RegisterClass(llvm::MCInst &Inst, unsigned RegNo,
774                             uint64_t Address, const void *Decoder) {
775   if (RegNo > 15)
776     return MCDisassembler::Fail;
777   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
778 }
779 
780 static const unsigned QPRDecoderTable[] = {
781      ARM::Q0,  ARM::Q1,  ARM::Q2,  ARM::Q3,
782      ARM::Q4,  ARM::Q5,  ARM::Q6,  ARM::Q7,
783      ARM::Q8,  ARM::Q9, ARM::Q10, ARM::Q11,
784     ARM::Q12, ARM::Q13, ARM::Q14, ARM::Q15
785 };
786 
787 
788 static DecodeStatus DecodeQPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
789                                    uint64_t Address, const void *Decoder) {
790   if (RegNo > 31)
791     return MCDisassembler::Fail;
792   RegNo >>= 1;
793 
794   unsigned Register = QPRDecoderTable[RegNo];
795   Inst.addOperand(MCOperand::CreateReg(Register));
796   return MCDisassembler::Success;
797 }
798 
799 static DecodeStatus DecodePredicateOperand(llvm::MCInst &Inst, unsigned Val,
800                                uint64_t Address, const void *Decoder) {
801   if (Val == 0xF) return MCDisassembler::Fail;
802   // AL predicate is not allowed on Thumb1 branches.
803   if (Inst.getOpcode() == ARM::tBcc && Val == 0xE)
804     return MCDisassembler::Fail;
805   Inst.addOperand(MCOperand::CreateImm(Val));
806   if (Val == ARMCC::AL) {
807     Inst.addOperand(MCOperand::CreateReg(0));
808   } else
809     Inst.addOperand(MCOperand::CreateReg(ARM::CPSR));
810   return MCDisassembler::Success;
811 }
812 
813 static DecodeStatus DecodeCCOutOperand(llvm::MCInst &Inst, unsigned Val,
814                                uint64_t Address, const void *Decoder) {
815   if (Val)
816     Inst.addOperand(MCOperand::CreateReg(ARM::CPSR));
817   else
818     Inst.addOperand(MCOperand::CreateReg(0));
819   return MCDisassembler::Success;
820 }
821 
822 static DecodeStatus DecodeSOImmOperand(llvm::MCInst &Inst, unsigned Val,
823                                uint64_t Address, const void *Decoder) {
824   uint32_t imm = Val & 0xFF;
825   uint32_t rot = (Val & 0xF00) >> 7;
826   uint32_t rot_imm = (imm >> rot) | (imm << (32-rot));
827   Inst.addOperand(MCOperand::CreateImm(rot_imm));
828   return MCDisassembler::Success;
829 }
830 
831 static DecodeStatus DecodeSORegImmOperand(llvm::MCInst &Inst, unsigned Val,
832                                uint64_t Address, const void *Decoder) {
833   DecodeStatus S = MCDisassembler::Success;
834 
835   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
836   unsigned type = fieldFromInstruction32(Val, 5, 2);
837   unsigned imm = fieldFromInstruction32(Val, 7, 5);
838 
839   // Register-immediate
840   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
841     return MCDisassembler::Fail;
842 
843   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
844   switch (type) {
845     case 0:
846       Shift = ARM_AM::lsl;
847       break;
848     case 1:
849       Shift = ARM_AM::lsr;
850       break;
851     case 2:
852       Shift = ARM_AM::asr;
853       break;
854     case 3:
855       Shift = ARM_AM::ror;
856       break;
857   }
858 
859   if (Shift == ARM_AM::ror && imm == 0)
860     Shift = ARM_AM::rrx;
861 
862   unsigned Op = Shift | (imm << 3);
863   Inst.addOperand(MCOperand::CreateImm(Op));
864 
865   return S;
866 }
867 
868 static DecodeStatus DecodeSORegRegOperand(llvm::MCInst &Inst, unsigned Val,
869                                uint64_t Address, const void *Decoder) {
870   DecodeStatus S = MCDisassembler::Success;
871 
872   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
873   unsigned type = fieldFromInstruction32(Val, 5, 2);
874   unsigned Rs = fieldFromInstruction32(Val, 8, 4);
875 
876   // Register-register
877   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
878     return MCDisassembler::Fail;
879   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rs, Address, Decoder)))
880     return MCDisassembler::Fail;
881 
882   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
883   switch (type) {
884     case 0:
885       Shift = ARM_AM::lsl;
886       break;
887     case 1:
888       Shift = ARM_AM::lsr;
889       break;
890     case 2:
891       Shift = ARM_AM::asr;
892       break;
893     case 3:
894       Shift = ARM_AM::ror;
895       break;
896   }
897 
898   Inst.addOperand(MCOperand::CreateImm(Shift));
899 
900   return S;
901 }
902 
903 static DecodeStatus DecodeRegListOperand(llvm::MCInst &Inst, unsigned Val,
904                                  uint64_t Address, const void *Decoder) {
905   DecodeStatus S = MCDisassembler::Success;
906 
907   // Empty register lists are not allowed.
908   if (CountPopulation_32(Val) == 0) return MCDisassembler::Fail;
909   for (unsigned i = 0; i < 16; ++i) {
910     if (Val & (1 << i)) {
911       if (!Check(S, DecodeGPRRegisterClass(Inst, i, Address, Decoder)))
912         return MCDisassembler::Fail;
913     }
914   }
915 
916   return S;
917 }
918 
919 static DecodeStatus DecodeSPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
920                                  uint64_t Address, const void *Decoder) {
921   DecodeStatus S = MCDisassembler::Success;
922 
923   unsigned Vd = fieldFromInstruction32(Val, 8, 4);
924   unsigned regs = Val & 0xFF;
925 
926   if (!Check(S, DecodeSPRRegisterClass(Inst, Vd, Address, Decoder)))
927     return MCDisassembler::Fail;
928   for (unsigned i = 0; i < (regs - 1); ++i) {
929     if (!Check(S, DecodeSPRRegisterClass(Inst, ++Vd, Address, Decoder)))
930       return MCDisassembler::Fail;
931   }
932 
933   return S;
934 }
935 
936 static DecodeStatus DecodeDPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
937                                  uint64_t Address, const void *Decoder) {
938   DecodeStatus S = MCDisassembler::Success;
939 
940   unsigned Vd = fieldFromInstruction32(Val, 8, 4);
941   unsigned regs = (Val & 0xFF) / 2;
942 
943   if (!Check(S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)))
944       return MCDisassembler::Fail;
945   for (unsigned i = 0; i < (regs - 1); ++i) {
946     if (!Check(S, DecodeDPRRegisterClass(Inst, ++Vd, Address, Decoder)))
947       return MCDisassembler::Fail;
948   }
949 
950   return S;
951 }
952 
953 static DecodeStatus DecodeBitfieldMaskOperand(llvm::MCInst &Inst, unsigned Val,
954                                       uint64_t Address, const void *Decoder) {
955   // This operand encodes a mask of contiguous zeros between a specified MSB
956   // and LSB.  To decode it, we create the mask of all bits MSB-and-lower,
957   // the mask of all bits LSB-and-lower, and then xor them to create
958   // the mask of that's all ones on [msb, lsb].  Finally we not it to
959   // create the final mask.
960   unsigned msb = fieldFromInstruction32(Val, 5, 5);
961   unsigned lsb = fieldFromInstruction32(Val, 0, 5);
962   uint32_t msb_mask = (1 << (msb+1)) - 1;
963   uint32_t lsb_mask = (1 << lsb) - 1;
964   Inst.addOperand(MCOperand::CreateImm(~(msb_mask ^ lsb_mask)));
965   return MCDisassembler::Success;
966 }
967 
968 static DecodeStatus DecodeCopMemInstruction(llvm::MCInst &Inst, unsigned Insn,
969                                   uint64_t Address, const void *Decoder) {
970   DecodeStatus S = MCDisassembler::Success;
971 
972   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
973   unsigned CRd = fieldFromInstruction32(Insn, 12, 4);
974   unsigned coproc = fieldFromInstruction32(Insn, 8, 4);
975   unsigned imm = fieldFromInstruction32(Insn, 0, 8);
976   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
977   unsigned U = fieldFromInstruction32(Insn, 23, 1);
978 
979   switch (Inst.getOpcode()) {
980     case ARM::LDC_OFFSET:
981     case ARM::LDC_PRE:
982     case ARM::LDC_POST:
983     case ARM::LDC_OPTION:
984     case ARM::LDCL_OFFSET:
985     case ARM::LDCL_PRE:
986     case ARM::LDCL_POST:
987     case ARM::LDCL_OPTION:
988     case ARM::STC_OFFSET:
989     case ARM::STC_PRE:
990     case ARM::STC_POST:
991     case ARM::STC_OPTION:
992     case ARM::STCL_OFFSET:
993     case ARM::STCL_PRE:
994     case ARM::STCL_POST:
995     case ARM::STCL_OPTION:
996     case ARM::t2LDC_OFFSET:
997     case ARM::t2LDC_PRE:
998     case ARM::t2LDC_POST:
999     case ARM::t2LDC_OPTION:
1000     case ARM::t2LDCL_OFFSET:
1001     case ARM::t2LDCL_PRE:
1002     case ARM::t2LDCL_POST:
1003     case ARM::t2LDCL_OPTION:
1004     case ARM::t2STC_OFFSET:
1005     case ARM::t2STC_PRE:
1006     case ARM::t2STC_POST:
1007     case ARM::t2STC_OPTION:
1008     case ARM::t2STCL_OFFSET:
1009     case ARM::t2STCL_PRE:
1010     case ARM::t2STCL_POST:
1011     case ARM::t2STCL_OPTION:
1012       if (coproc == 0xA || coproc == 0xB)
1013         return MCDisassembler::Fail;
1014       break;
1015     default:
1016       break;
1017   }
1018 
1019   Inst.addOperand(MCOperand::CreateImm(coproc));
1020   Inst.addOperand(MCOperand::CreateImm(CRd));
1021   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1022     return MCDisassembler::Fail;
1023   switch (Inst.getOpcode()) {
1024     case ARM::LDC_OPTION:
1025     case ARM::LDCL_OPTION:
1026     case ARM::LDC2_OPTION:
1027     case ARM::LDC2L_OPTION:
1028     case ARM::STC_OPTION:
1029     case ARM::STCL_OPTION:
1030     case ARM::STC2_OPTION:
1031     case ARM::STC2L_OPTION:
1032     case ARM::LDCL_POST:
1033     case ARM::STCL_POST:
1034     case ARM::LDC2L_POST:
1035     case ARM::STC2L_POST:
1036     case ARM::t2LDC_OPTION:
1037     case ARM::t2LDCL_OPTION:
1038     case ARM::t2STC_OPTION:
1039     case ARM::t2STCL_OPTION:
1040     case ARM::t2LDCL_POST:
1041     case ARM::t2STCL_POST:
1042       break;
1043     default:
1044       Inst.addOperand(MCOperand::CreateReg(0));
1045       break;
1046   }
1047 
1048   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1049   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1050 
1051   bool writeback = (P == 0) || (W == 1);
1052   unsigned idx_mode = 0;
1053   if (P && writeback)
1054     idx_mode = ARMII::IndexModePre;
1055   else if (!P && writeback)
1056     idx_mode = ARMII::IndexModePost;
1057 
1058   switch (Inst.getOpcode()) {
1059     case ARM::LDCL_POST:
1060     case ARM::STCL_POST:
1061     case ARM::t2LDCL_POST:
1062     case ARM::t2STCL_POST:
1063     case ARM::LDC2L_POST:
1064     case ARM::STC2L_POST:
1065       imm |= U << 8;
1066     case ARM::LDC_OPTION:
1067     case ARM::LDCL_OPTION:
1068     case ARM::LDC2_OPTION:
1069     case ARM::LDC2L_OPTION:
1070     case ARM::STC_OPTION:
1071     case ARM::STCL_OPTION:
1072     case ARM::STC2_OPTION:
1073     case ARM::STC2L_OPTION:
1074     case ARM::t2LDC_OPTION:
1075     case ARM::t2LDCL_OPTION:
1076     case ARM::t2STC_OPTION:
1077     case ARM::t2STCL_OPTION:
1078       Inst.addOperand(MCOperand::CreateImm(imm));
1079       break;
1080     default:
1081       if (U)
1082         Inst.addOperand(MCOperand::CreateImm(
1083             ARM_AM::getAM2Opc(ARM_AM::add, imm, ARM_AM::lsl, idx_mode)));
1084       else
1085         Inst.addOperand(MCOperand::CreateImm(
1086             ARM_AM::getAM2Opc(ARM_AM::sub, imm, ARM_AM::lsl, idx_mode)));
1087       break;
1088   }
1089 
1090   switch (Inst.getOpcode()) {
1091     case ARM::LDC_OFFSET:
1092     case ARM::LDC_PRE:
1093     case ARM::LDC_POST:
1094     case ARM::LDC_OPTION:
1095     case ARM::LDCL_OFFSET:
1096     case ARM::LDCL_PRE:
1097     case ARM::LDCL_POST:
1098     case ARM::LDCL_OPTION:
1099     case ARM::STC_OFFSET:
1100     case ARM::STC_PRE:
1101     case ARM::STC_POST:
1102     case ARM::STC_OPTION:
1103     case ARM::STCL_OFFSET:
1104     case ARM::STCL_PRE:
1105     case ARM::STCL_POST:
1106     case ARM::STCL_OPTION:
1107       if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1108         return MCDisassembler::Fail;
1109       break;
1110     default:
1111       break;
1112   }
1113 
1114   return S;
1115 }
1116 
1117 static DecodeStatus
1118 DecodeAddrMode2IdxInstruction(llvm::MCInst &Inst, unsigned Insn,
1119                               uint64_t Address, const void *Decoder) {
1120   DecodeStatus S = MCDisassembler::Success;
1121 
1122   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1123   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
1124   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1125   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
1126   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1127   unsigned reg = fieldFromInstruction32(Insn, 25, 1);
1128   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1129   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1130 
1131   // On stores, the writeback operand precedes Rt.
1132   switch (Inst.getOpcode()) {
1133     case ARM::STR_POST_IMM:
1134     case ARM::STR_POST_REG:
1135     case ARM::STRB_POST_IMM:
1136     case ARM::STRB_POST_REG:
1137     case ARM::STRT_POST_REG:
1138     case ARM::STRT_POST_IMM:
1139     case ARM::STRBT_POST_REG:
1140     case ARM::STRBT_POST_IMM:
1141       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1142         return MCDisassembler::Fail;
1143       break;
1144     default:
1145       break;
1146   }
1147 
1148   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
1149     return MCDisassembler::Fail;
1150 
1151   // On loads, the writeback operand comes after Rt.
1152   switch (Inst.getOpcode()) {
1153     case ARM::LDR_POST_IMM:
1154     case ARM::LDR_POST_REG:
1155     case ARM::LDRB_POST_IMM:
1156     case ARM::LDRB_POST_REG:
1157     case ARM::LDRBT_POST_REG:
1158     case ARM::LDRBT_POST_IMM:
1159     case ARM::LDRT_POST_REG:
1160     case ARM::LDRT_POST_IMM:
1161       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1162         return MCDisassembler::Fail;
1163       break;
1164     default:
1165       break;
1166   }
1167 
1168   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1169     return MCDisassembler::Fail;
1170 
1171   ARM_AM::AddrOpc Op = ARM_AM::add;
1172   if (!fieldFromInstruction32(Insn, 23, 1))
1173     Op = ARM_AM::sub;
1174 
1175   bool writeback = (P == 0) || (W == 1);
1176   unsigned idx_mode = 0;
1177   if (P && writeback)
1178     idx_mode = ARMII::IndexModePre;
1179   else if (!P && writeback)
1180     idx_mode = ARMII::IndexModePost;
1181 
1182   if (writeback && (Rn == 15 || Rn == Rt))
1183     S = MCDisassembler::SoftFail; // UNPREDICTABLE
1184 
1185   if (reg) {
1186     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1187       return MCDisassembler::Fail;
1188     ARM_AM::ShiftOpc Opc = ARM_AM::lsl;
1189     switch( fieldFromInstruction32(Insn, 5, 2)) {
1190       case 0:
1191         Opc = ARM_AM::lsl;
1192         break;
1193       case 1:
1194         Opc = ARM_AM::lsr;
1195         break;
1196       case 2:
1197         Opc = ARM_AM::asr;
1198         break;
1199       case 3:
1200         Opc = ARM_AM::ror;
1201         break;
1202       default:
1203         return MCDisassembler::Fail;
1204     }
1205     unsigned amt = fieldFromInstruction32(Insn, 7, 5);
1206     unsigned imm = ARM_AM::getAM2Opc(Op, amt, Opc, idx_mode);
1207 
1208     Inst.addOperand(MCOperand::CreateImm(imm));
1209   } else {
1210     Inst.addOperand(MCOperand::CreateReg(0));
1211     unsigned tmp = ARM_AM::getAM2Opc(Op, imm, ARM_AM::lsl, idx_mode);
1212     Inst.addOperand(MCOperand::CreateImm(tmp));
1213   }
1214 
1215   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1216     return MCDisassembler::Fail;
1217 
1218   return S;
1219 }
1220 
1221 static DecodeStatus DecodeSORegMemOperand(llvm::MCInst &Inst, unsigned Val,
1222                                   uint64_t Address, const void *Decoder) {
1223   DecodeStatus S = MCDisassembler::Success;
1224 
1225   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
1226   unsigned Rm = fieldFromInstruction32(Val,  0, 4);
1227   unsigned type = fieldFromInstruction32(Val, 5, 2);
1228   unsigned imm = fieldFromInstruction32(Val, 7, 5);
1229   unsigned U = fieldFromInstruction32(Val, 12, 1);
1230 
1231   ARM_AM::ShiftOpc ShOp = ARM_AM::lsl;
1232   switch (type) {
1233     case 0:
1234       ShOp = ARM_AM::lsl;
1235       break;
1236     case 1:
1237       ShOp = ARM_AM::lsr;
1238       break;
1239     case 2:
1240       ShOp = ARM_AM::asr;
1241       break;
1242     case 3:
1243       ShOp = ARM_AM::ror;
1244       break;
1245   }
1246 
1247   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1248     return MCDisassembler::Fail;
1249   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1250     return MCDisassembler::Fail;
1251   unsigned shift;
1252   if (U)
1253     shift = ARM_AM::getAM2Opc(ARM_AM::add, imm, ShOp);
1254   else
1255     shift = ARM_AM::getAM2Opc(ARM_AM::sub, imm, ShOp);
1256   Inst.addOperand(MCOperand::CreateImm(shift));
1257 
1258   return S;
1259 }
1260 
1261 static DecodeStatus
1262 DecodeAddrMode3Instruction(llvm::MCInst &Inst, unsigned Insn,
1263                            uint64_t Address, const void *Decoder) {
1264   DecodeStatus S = MCDisassembler::Success;
1265 
1266   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
1267   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1268   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1269   unsigned type = fieldFromInstruction32(Insn, 22, 1);
1270   unsigned imm = fieldFromInstruction32(Insn, 8, 4);
1271   unsigned U = ((~fieldFromInstruction32(Insn, 23, 1)) & 1) << 8;
1272   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1273   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1274   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1275 
1276   bool writeback = (W == 1) | (P == 0);
1277 
1278   // For {LD,ST}RD, Rt must be even, else undefined.
1279   switch (Inst.getOpcode()) {
1280     case ARM::STRD:
1281     case ARM::STRD_PRE:
1282     case ARM::STRD_POST:
1283     case ARM::LDRD:
1284     case ARM::LDRD_PRE:
1285     case ARM::LDRD_POST:
1286       if (Rt & 0x1) return MCDisassembler::Fail;
1287       break;
1288     default:
1289       break;
1290   }
1291 
1292   if (writeback) { // Writeback
1293     if (P)
1294       U |= ARMII::IndexModePre << 9;
1295     else
1296       U |= ARMII::IndexModePost << 9;
1297 
1298     // On stores, the writeback operand precedes Rt.
1299     switch (Inst.getOpcode()) {
1300     case ARM::STRD:
1301     case ARM::STRD_PRE:
1302     case ARM::STRD_POST:
1303     case ARM::STRH:
1304     case ARM::STRH_PRE:
1305     case ARM::STRH_POST:
1306       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1307         return MCDisassembler::Fail;
1308       break;
1309     default:
1310       break;
1311     }
1312   }
1313 
1314   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
1315     return MCDisassembler::Fail;
1316   switch (Inst.getOpcode()) {
1317     case ARM::STRD:
1318     case ARM::STRD_PRE:
1319     case ARM::STRD_POST:
1320     case ARM::LDRD:
1321     case ARM::LDRD_PRE:
1322     case ARM::LDRD_POST:
1323       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
1324         return MCDisassembler::Fail;
1325       break;
1326     default:
1327       break;
1328   }
1329 
1330   if (writeback) {
1331     // On loads, the writeback operand comes after Rt.
1332     switch (Inst.getOpcode()) {
1333     case ARM::LDRD:
1334     case ARM::LDRD_PRE:
1335     case ARM::LDRD_POST:
1336     case ARM::LDRH:
1337     case ARM::LDRH_PRE:
1338     case ARM::LDRH_POST:
1339     case ARM::LDRSH:
1340     case ARM::LDRSH_PRE:
1341     case ARM::LDRSH_POST:
1342     case ARM::LDRSB:
1343     case ARM::LDRSB_PRE:
1344     case ARM::LDRSB_POST:
1345     case ARM::LDRHTr:
1346     case ARM::LDRSBTr:
1347       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1348         return MCDisassembler::Fail;
1349       break;
1350     default:
1351       break;
1352     }
1353   }
1354 
1355   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1356     return MCDisassembler::Fail;
1357 
1358   if (type) {
1359     Inst.addOperand(MCOperand::CreateReg(0));
1360     Inst.addOperand(MCOperand::CreateImm(U | (imm << 4) | Rm));
1361   } else {
1362     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1363     return MCDisassembler::Fail;
1364     Inst.addOperand(MCOperand::CreateImm(U));
1365   }
1366 
1367   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1368     return MCDisassembler::Fail;
1369 
1370   return S;
1371 }
1372 
1373 static DecodeStatus DecodeRFEInstruction(llvm::MCInst &Inst, unsigned Insn,
1374                                  uint64_t Address, const void *Decoder) {
1375   DecodeStatus S = MCDisassembler::Success;
1376 
1377   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1378   unsigned mode = fieldFromInstruction32(Insn, 23, 2);
1379 
1380   switch (mode) {
1381     case 0:
1382       mode = ARM_AM::da;
1383       break;
1384     case 1:
1385       mode = ARM_AM::ia;
1386       break;
1387     case 2:
1388       mode = ARM_AM::db;
1389       break;
1390     case 3:
1391       mode = ARM_AM::ib;
1392       break;
1393   }
1394 
1395   Inst.addOperand(MCOperand::CreateImm(mode));
1396   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1397     return MCDisassembler::Fail;
1398 
1399   return S;
1400 }
1401 
1402 static DecodeStatus DecodeMemMultipleWritebackInstruction(llvm::MCInst &Inst,
1403                                   unsigned Insn,
1404                                   uint64_t Address, const void *Decoder) {
1405   DecodeStatus S = MCDisassembler::Success;
1406 
1407   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1408   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1409   unsigned reglist = fieldFromInstruction32(Insn, 0, 16);
1410 
1411   if (pred == 0xF) {
1412     switch (Inst.getOpcode()) {
1413       case ARM::LDMDA:
1414         Inst.setOpcode(ARM::RFEDA);
1415         break;
1416       case ARM::LDMDA_UPD:
1417         Inst.setOpcode(ARM::RFEDA_UPD);
1418         break;
1419       case ARM::LDMDB:
1420         Inst.setOpcode(ARM::RFEDB);
1421         break;
1422       case ARM::LDMDB_UPD:
1423         Inst.setOpcode(ARM::RFEDB_UPD);
1424         break;
1425       case ARM::LDMIA:
1426         Inst.setOpcode(ARM::RFEIA);
1427         break;
1428       case ARM::LDMIA_UPD:
1429         Inst.setOpcode(ARM::RFEIA_UPD);
1430         break;
1431       case ARM::LDMIB:
1432         Inst.setOpcode(ARM::RFEIB);
1433         break;
1434       case ARM::LDMIB_UPD:
1435         Inst.setOpcode(ARM::RFEIB_UPD);
1436         break;
1437       case ARM::STMDA:
1438         Inst.setOpcode(ARM::SRSDA);
1439         break;
1440       case ARM::STMDA_UPD:
1441         Inst.setOpcode(ARM::SRSDA_UPD);
1442         break;
1443       case ARM::STMDB:
1444         Inst.setOpcode(ARM::SRSDB);
1445         break;
1446       case ARM::STMDB_UPD:
1447         Inst.setOpcode(ARM::SRSDB_UPD);
1448         break;
1449       case ARM::STMIA:
1450         Inst.setOpcode(ARM::SRSIA);
1451         break;
1452       case ARM::STMIA_UPD:
1453         Inst.setOpcode(ARM::SRSIA_UPD);
1454         break;
1455       case ARM::STMIB:
1456         Inst.setOpcode(ARM::SRSIB);
1457         break;
1458       case ARM::STMIB_UPD:
1459         Inst.setOpcode(ARM::SRSIB_UPD);
1460         break;
1461       default:
1462         if (!Check(S, MCDisassembler::Fail)) return MCDisassembler::Fail;
1463     }
1464 
1465     // For stores (which become SRS's, the only operand is the mode.
1466     if (fieldFromInstruction32(Insn, 20, 1) == 0) {
1467       Inst.addOperand(
1468           MCOperand::CreateImm(fieldFromInstruction32(Insn, 0, 4)));
1469       return S;
1470     }
1471 
1472     return DecodeRFEInstruction(Inst, Insn, Address, Decoder);
1473   }
1474 
1475   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1476     return MCDisassembler::Fail;
1477   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1478     return MCDisassembler::Fail; // Tied
1479   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1480     return MCDisassembler::Fail;
1481   if (!Check(S, DecodeRegListOperand(Inst, reglist, Address, Decoder)))
1482     return MCDisassembler::Fail;
1483 
1484   return S;
1485 }
1486 
1487 static DecodeStatus DecodeCPSInstruction(llvm::MCInst &Inst, unsigned Insn,
1488                                  uint64_t Address, const void *Decoder) {
1489   unsigned imod = fieldFromInstruction32(Insn, 18, 2);
1490   unsigned M = fieldFromInstruction32(Insn, 17, 1);
1491   unsigned iflags = fieldFromInstruction32(Insn, 6, 3);
1492   unsigned mode = fieldFromInstruction32(Insn, 0, 5);
1493 
1494   DecodeStatus S = MCDisassembler::Success;
1495 
1496   // imod == '01' --> UNPREDICTABLE
1497   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
1498   // return failure here.  The '01' imod value is unprintable, so there's
1499   // nothing useful we could do even if we returned UNPREDICTABLE.
1500 
1501   if (imod == 1) return MCDisassembler::Fail;
1502 
1503   if (imod && M) {
1504     Inst.setOpcode(ARM::CPS3p);
1505     Inst.addOperand(MCOperand::CreateImm(imod));
1506     Inst.addOperand(MCOperand::CreateImm(iflags));
1507     Inst.addOperand(MCOperand::CreateImm(mode));
1508   } else if (imod && !M) {
1509     Inst.setOpcode(ARM::CPS2p);
1510     Inst.addOperand(MCOperand::CreateImm(imod));
1511     Inst.addOperand(MCOperand::CreateImm(iflags));
1512     if (mode) S = MCDisassembler::SoftFail;
1513   } else if (!imod && M) {
1514     Inst.setOpcode(ARM::CPS1p);
1515     Inst.addOperand(MCOperand::CreateImm(mode));
1516     if (iflags) S = MCDisassembler::SoftFail;
1517   } else {
1518     // imod == '00' && M == '0' --> UNPREDICTABLE
1519     Inst.setOpcode(ARM::CPS1p);
1520     Inst.addOperand(MCOperand::CreateImm(mode));
1521     S = MCDisassembler::SoftFail;
1522   }
1523 
1524   return S;
1525 }
1526 
1527 static DecodeStatus DecodeT2CPSInstruction(llvm::MCInst &Inst, unsigned Insn,
1528                                  uint64_t Address, const void *Decoder) {
1529   unsigned imod = fieldFromInstruction32(Insn, 9, 2);
1530   unsigned M = fieldFromInstruction32(Insn, 8, 1);
1531   unsigned iflags = fieldFromInstruction32(Insn, 5, 3);
1532   unsigned mode = fieldFromInstruction32(Insn, 0, 5);
1533 
1534   DecodeStatus S = MCDisassembler::Success;
1535 
1536   // imod == '01' --> UNPREDICTABLE
1537   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
1538   // return failure here.  The '01' imod value is unprintable, so there's
1539   // nothing useful we could do even if we returned UNPREDICTABLE.
1540 
1541   if (imod == 1) return MCDisassembler::Fail;
1542 
1543   if (imod && M) {
1544     Inst.setOpcode(ARM::t2CPS3p);
1545     Inst.addOperand(MCOperand::CreateImm(imod));
1546     Inst.addOperand(MCOperand::CreateImm(iflags));
1547     Inst.addOperand(MCOperand::CreateImm(mode));
1548   } else if (imod && !M) {
1549     Inst.setOpcode(ARM::t2CPS2p);
1550     Inst.addOperand(MCOperand::CreateImm(imod));
1551     Inst.addOperand(MCOperand::CreateImm(iflags));
1552     if (mode) S = MCDisassembler::SoftFail;
1553   } else if (!imod && M) {
1554     Inst.setOpcode(ARM::t2CPS1p);
1555     Inst.addOperand(MCOperand::CreateImm(mode));
1556     if (iflags) S = MCDisassembler::SoftFail;
1557   } else {
1558     // imod == '00' && M == '0' --> UNPREDICTABLE
1559     Inst.setOpcode(ARM::t2CPS1p);
1560     Inst.addOperand(MCOperand::CreateImm(mode));
1561     S = MCDisassembler::SoftFail;
1562   }
1563 
1564   return S;
1565 }
1566 
1567 
1568 static DecodeStatus DecodeSMLAInstruction(llvm::MCInst &Inst, unsigned Insn,
1569                                  uint64_t Address, const void *Decoder) {
1570   DecodeStatus S = MCDisassembler::Success;
1571 
1572   unsigned Rd = fieldFromInstruction32(Insn, 16, 4);
1573   unsigned Rn = fieldFromInstruction32(Insn, 0, 4);
1574   unsigned Rm = fieldFromInstruction32(Insn, 8, 4);
1575   unsigned Ra = fieldFromInstruction32(Insn, 12, 4);
1576   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1577 
1578   if (pred == 0xF)
1579     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
1580 
1581   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
1582     return MCDisassembler::Fail;
1583   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
1584     return MCDisassembler::Fail;
1585   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1586     return MCDisassembler::Fail;
1587   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Ra, Address, Decoder)))
1588     return MCDisassembler::Fail;
1589 
1590   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1591     return MCDisassembler::Fail;
1592 
1593   return S;
1594 }
1595 
1596 static DecodeStatus DecodeAddrModeImm12Operand(llvm::MCInst &Inst, unsigned Val,
1597                            uint64_t Address, const void *Decoder) {
1598   DecodeStatus S = MCDisassembler::Success;
1599 
1600   unsigned add = fieldFromInstruction32(Val, 12, 1);
1601   unsigned imm = fieldFromInstruction32(Val, 0, 12);
1602   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
1603 
1604   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1605     return MCDisassembler::Fail;
1606 
1607   if (!add) imm *= -1;
1608   if (imm == 0 && !add) imm = INT32_MIN;
1609   Inst.addOperand(MCOperand::CreateImm(imm));
1610 
1611   return S;
1612 }
1613 
1614 static DecodeStatus DecodeAddrMode5Operand(llvm::MCInst &Inst, unsigned Val,
1615                                    uint64_t Address, const void *Decoder) {
1616   DecodeStatus S = MCDisassembler::Success;
1617 
1618   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
1619   unsigned U = fieldFromInstruction32(Val, 8, 1);
1620   unsigned imm = fieldFromInstruction32(Val, 0, 8);
1621 
1622   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1623     return MCDisassembler::Fail;
1624 
1625   if (U)
1626     Inst.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(ARM_AM::add, imm)));
1627   else
1628     Inst.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(ARM_AM::sub, imm)));
1629 
1630   return S;
1631 }
1632 
1633 static DecodeStatus DecodeAddrMode7Operand(llvm::MCInst &Inst, unsigned Val,
1634                                    uint64_t Address, const void *Decoder) {
1635   return DecodeGPRRegisterClass(Inst, Val, Address, Decoder);
1636 }
1637 
1638 static DecodeStatus
1639 DecodeBranchImmInstruction(llvm::MCInst &Inst, unsigned Insn,
1640                            uint64_t Address, const void *Decoder) {
1641   DecodeStatus S = MCDisassembler::Success;
1642 
1643   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1644   unsigned imm = fieldFromInstruction32(Insn, 0, 24) << 2;
1645 
1646   if (pred == 0xF) {
1647     Inst.setOpcode(ARM::BLXi);
1648     imm |= fieldFromInstruction32(Insn, 24, 1) << 1;
1649     Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(imm)));
1650     return S;
1651   }
1652 
1653   Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(imm)));
1654   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1655     return MCDisassembler::Fail;
1656 
1657   return S;
1658 }
1659 
1660 
1661 static DecodeStatus DecodeVCVTImmOperand(llvm::MCInst &Inst, unsigned Val,
1662                                  uint64_t Address, const void *Decoder) {
1663   Inst.addOperand(MCOperand::CreateImm(64 - Val));
1664   return MCDisassembler::Success;
1665 }
1666 
1667 static DecodeStatus DecodeAddrMode6Operand(llvm::MCInst &Inst, unsigned Val,
1668                                    uint64_t Address, const void *Decoder) {
1669   DecodeStatus S = MCDisassembler::Success;
1670 
1671   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
1672   unsigned align = fieldFromInstruction32(Val, 4, 2);
1673 
1674   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1675     return MCDisassembler::Fail;
1676   if (!align)
1677     Inst.addOperand(MCOperand::CreateImm(0));
1678   else
1679     Inst.addOperand(MCOperand::CreateImm(4 << align));
1680 
1681   return S;
1682 }
1683 
1684 static DecodeStatus DecodeVLDInstruction(llvm::MCInst &Inst, unsigned Insn,
1685                                    uint64_t Address, const void *Decoder) {
1686   DecodeStatus S = MCDisassembler::Success;
1687 
1688   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
1689   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
1690   unsigned wb = fieldFromInstruction32(Insn, 16, 4);
1691   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1692   Rn |= fieldFromInstruction32(Insn, 4, 2) << 4;
1693   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1694 
1695   // First output register
1696   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
1697     return MCDisassembler::Fail;
1698 
1699   // Second output register
1700   switch (Inst.getOpcode()) {
1701     case ARM::VLD1q8:
1702     case ARM::VLD1q16:
1703     case ARM::VLD1q32:
1704     case ARM::VLD1q64:
1705     case ARM::VLD1q8_UPD:
1706     case ARM::VLD1q16_UPD:
1707     case ARM::VLD1q32_UPD:
1708     case ARM::VLD1q64_UPD:
1709     case ARM::VLD1d8T:
1710     case ARM::VLD1d16T:
1711     case ARM::VLD1d32T:
1712     case ARM::VLD1d64T:
1713     case ARM::VLD1d8T_UPD:
1714     case ARM::VLD1d16T_UPD:
1715     case ARM::VLD1d32T_UPD:
1716     case ARM::VLD1d64T_UPD:
1717     case ARM::VLD1d8Q:
1718     case ARM::VLD1d16Q:
1719     case ARM::VLD1d32Q:
1720     case ARM::VLD1d64Q:
1721     case ARM::VLD1d8Q_UPD:
1722     case ARM::VLD1d16Q_UPD:
1723     case ARM::VLD1d32Q_UPD:
1724     case ARM::VLD1d64Q_UPD:
1725     case ARM::VLD2d8:
1726     case ARM::VLD2d16:
1727     case ARM::VLD2d32:
1728     case ARM::VLD2d8_UPD:
1729     case ARM::VLD2d16_UPD:
1730     case ARM::VLD2d32_UPD:
1731     case ARM::VLD2q8:
1732     case ARM::VLD2q16:
1733     case ARM::VLD2q32:
1734     case ARM::VLD2q8_UPD:
1735     case ARM::VLD2q16_UPD:
1736     case ARM::VLD2q32_UPD:
1737     case ARM::VLD3d8:
1738     case ARM::VLD3d16:
1739     case ARM::VLD3d32:
1740     case ARM::VLD3d8_UPD:
1741     case ARM::VLD3d16_UPD:
1742     case ARM::VLD3d32_UPD:
1743     case ARM::VLD4d8:
1744     case ARM::VLD4d16:
1745     case ARM::VLD4d32:
1746     case ARM::VLD4d8_UPD:
1747     case ARM::VLD4d16_UPD:
1748     case ARM::VLD4d32_UPD:
1749       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
1750         return MCDisassembler::Fail;
1751       break;
1752     case ARM::VLD2b8:
1753     case ARM::VLD2b16:
1754     case ARM::VLD2b32:
1755     case ARM::VLD2b8_UPD:
1756     case ARM::VLD2b16_UPD:
1757     case ARM::VLD2b32_UPD:
1758     case ARM::VLD3q8:
1759     case ARM::VLD3q16:
1760     case ARM::VLD3q32:
1761     case ARM::VLD3q8_UPD:
1762     case ARM::VLD3q16_UPD:
1763     case ARM::VLD3q32_UPD:
1764     case ARM::VLD4q8:
1765     case ARM::VLD4q16:
1766     case ARM::VLD4q32:
1767     case ARM::VLD4q8_UPD:
1768     case ARM::VLD4q16_UPD:
1769     case ARM::VLD4q32_UPD:
1770       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
1771         return MCDisassembler::Fail;
1772     default:
1773       break;
1774   }
1775 
1776   // Third output register
1777   switch(Inst.getOpcode()) {
1778     case ARM::VLD1d8T:
1779     case ARM::VLD1d16T:
1780     case ARM::VLD1d32T:
1781     case ARM::VLD1d64T:
1782     case ARM::VLD1d8T_UPD:
1783     case ARM::VLD1d16T_UPD:
1784     case ARM::VLD1d32T_UPD:
1785     case ARM::VLD1d64T_UPD:
1786     case ARM::VLD1d8Q:
1787     case ARM::VLD1d16Q:
1788     case ARM::VLD1d32Q:
1789     case ARM::VLD1d64Q:
1790     case ARM::VLD1d8Q_UPD:
1791     case ARM::VLD1d16Q_UPD:
1792     case ARM::VLD1d32Q_UPD:
1793     case ARM::VLD1d64Q_UPD:
1794     case ARM::VLD2q8:
1795     case ARM::VLD2q16:
1796     case ARM::VLD2q32:
1797     case ARM::VLD2q8_UPD:
1798     case ARM::VLD2q16_UPD:
1799     case ARM::VLD2q32_UPD:
1800     case ARM::VLD3d8:
1801     case ARM::VLD3d16:
1802     case ARM::VLD3d32:
1803     case ARM::VLD3d8_UPD:
1804     case ARM::VLD3d16_UPD:
1805     case ARM::VLD3d32_UPD:
1806     case ARM::VLD4d8:
1807     case ARM::VLD4d16:
1808     case ARM::VLD4d32:
1809     case ARM::VLD4d8_UPD:
1810     case ARM::VLD4d16_UPD:
1811     case ARM::VLD4d32_UPD:
1812       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
1813         return MCDisassembler::Fail;
1814       break;
1815     case ARM::VLD3q8:
1816     case ARM::VLD3q16:
1817     case ARM::VLD3q32:
1818     case ARM::VLD3q8_UPD:
1819     case ARM::VLD3q16_UPD:
1820     case ARM::VLD3q32_UPD:
1821     case ARM::VLD4q8:
1822     case ARM::VLD4q16:
1823     case ARM::VLD4q32:
1824     case ARM::VLD4q8_UPD:
1825     case ARM::VLD4q16_UPD:
1826     case ARM::VLD4q32_UPD:
1827       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
1828         return MCDisassembler::Fail;
1829       break;
1830     default:
1831       break;
1832   }
1833 
1834   // Fourth output register
1835   switch (Inst.getOpcode()) {
1836     case ARM::VLD1d8Q:
1837     case ARM::VLD1d16Q:
1838     case ARM::VLD1d32Q:
1839     case ARM::VLD1d64Q:
1840     case ARM::VLD1d8Q_UPD:
1841     case ARM::VLD1d16Q_UPD:
1842     case ARM::VLD1d32Q_UPD:
1843     case ARM::VLD1d64Q_UPD:
1844     case ARM::VLD2q8:
1845     case ARM::VLD2q16:
1846     case ARM::VLD2q32:
1847     case ARM::VLD2q8_UPD:
1848     case ARM::VLD2q16_UPD:
1849     case ARM::VLD2q32_UPD:
1850     case ARM::VLD4d8:
1851     case ARM::VLD4d16:
1852     case ARM::VLD4d32:
1853     case ARM::VLD4d8_UPD:
1854     case ARM::VLD4d16_UPD:
1855     case ARM::VLD4d32_UPD:
1856       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
1857         return MCDisassembler::Fail;
1858       break;
1859     case ARM::VLD4q8:
1860     case ARM::VLD4q16:
1861     case ARM::VLD4q32:
1862     case ARM::VLD4q8_UPD:
1863     case ARM::VLD4q16_UPD:
1864     case ARM::VLD4q32_UPD:
1865       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
1866         return MCDisassembler::Fail;
1867       break;
1868     default:
1869       break;
1870   }
1871 
1872   // Writeback operand
1873   switch (Inst.getOpcode()) {
1874     case ARM::VLD1d8_UPD:
1875     case ARM::VLD1d16_UPD:
1876     case ARM::VLD1d32_UPD:
1877     case ARM::VLD1d64_UPD:
1878     case ARM::VLD1q8_UPD:
1879     case ARM::VLD1q16_UPD:
1880     case ARM::VLD1q32_UPD:
1881     case ARM::VLD1q64_UPD:
1882     case ARM::VLD1d8T_UPD:
1883     case ARM::VLD1d16T_UPD:
1884     case ARM::VLD1d32T_UPD:
1885     case ARM::VLD1d64T_UPD:
1886     case ARM::VLD1d8Q_UPD:
1887     case ARM::VLD1d16Q_UPD:
1888     case ARM::VLD1d32Q_UPD:
1889     case ARM::VLD1d64Q_UPD:
1890     case ARM::VLD2d8_UPD:
1891     case ARM::VLD2d16_UPD:
1892     case ARM::VLD2d32_UPD:
1893     case ARM::VLD2q8_UPD:
1894     case ARM::VLD2q16_UPD:
1895     case ARM::VLD2q32_UPD:
1896     case ARM::VLD2b8_UPD:
1897     case ARM::VLD2b16_UPD:
1898     case ARM::VLD2b32_UPD:
1899     case ARM::VLD3d8_UPD:
1900     case ARM::VLD3d16_UPD:
1901     case ARM::VLD3d32_UPD:
1902     case ARM::VLD3q8_UPD:
1903     case ARM::VLD3q16_UPD:
1904     case ARM::VLD3q32_UPD:
1905     case ARM::VLD4d8_UPD:
1906     case ARM::VLD4d16_UPD:
1907     case ARM::VLD4d32_UPD:
1908     case ARM::VLD4q8_UPD:
1909     case ARM::VLD4q16_UPD:
1910     case ARM::VLD4q32_UPD:
1911       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
1912         return MCDisassembler::Fail;
1913       break;
1914     default:
1915       break;
1916   }
1917 
1918   // AddrMode6 Base (register+alignment)
1919   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
1920     return MCDisassembler::Fail;
1921 
1922   // AddrMode6 Offset (register)
1923   if (Rm == 0xD)
1924     Inst.addOperand(MCOperand::CreateReg(0));
1925   else if (Rm != 0xF) {
1926     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1927       return MCDisassembler::Fail;
1928   }
1929 
1930   return S;
1931 }
1932 
1933 static DecodeStatus DecodeVSTInstruction(llvm::MCInst &Inst, unsigned Insn,
1934                                  uint64_t Address, const void *Decoder) {
1935   DecodeStatus S = MCDisassembler::Success;
1936 
1937   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
1938   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
1939   unsigned wb = fieldFromInstruction32(Insn, 16, 4);
1940   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1941   Rn |= fieldFromInstruction32(Insn, 4, 2) << 4;
1942   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1943 
1944   // Writeback Operand
1945   switch (Inst.getOpcode()) {
1946     case ARM::VST1d8_UPD:
1947     case ARM::VST1d16_UPD:
1948     case ARM::VST1d32_UPD:
1949     case ARM::VST1d64_UPD:
1950     case ARM::VST1q8_UPD:
1951     case ARM::VST1q16_UPD:
1952     case ARM::VST1q32_UPD:
1953     case ARM::VST1q64_UPD:
1954     case ARM::VST1d8T_UPD:
1955     case ARM::VST1d16T_UPD:
1956     case ARM::VST1d32T_UPD:
1957     case ARM::VST1d64T_UPD:
1958     case ARM::VST1d8Q_UPD:
1959     case ARM::VST1d16Q_UPD:
1960     case ARM::VST1d32Q_UPD:
1961     case ARM::VST1d64Q_UPD:
1962     case ARM::VST2d8_UPD:
1963     case ARM::VST2d16_UPD:
1964     case ARM::VST2d32_UPD:
1965     case ARM::VST2q8_UPD:
1966     case ARM::VST2q16_UPD:
1967     case ARM::VST2q32_UPD:
1968     case ARM::VST2b8_UPD:
1969     case ARM::VST2b16_UPD:
1970     case ARM::VST2b32_UPD:
1971     case ARM::VST3d8_UPD:
1972     case ARM::VST3d16_UPD:
1973     case ARM::VST3d32_UPD:
1974     case ARM::VST3q8_UPD:
1975     case ARM::VST3q16_UPD:
1976     case ARM::VST3q32_UPD:
1977     case ARM::VST4d8_UPD:
1978     case ARM::VST4d16_UPD:
1979     case ARM::VST4d32_UPD:
1980     case ARM::VST4q8_UPD:
1981     case ARM::VST4q16_UPD:
1982     case ARM::VST4q32_UPD:
1983       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
1984         return MCDisassembler::Fail;
1985       break;
1986     default:
1987       break;
1988   }
1989 
1990   // AddrMode6 Base (register+alignment)
1991   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
1992     return MCDisassembler::Fail;
1993 
1994   // AddrMode6 Offset (register)
1995   if (Rm == 0xD)
1996     Inst.addOperand(MCOperand::CreateReg(0));
1997   else if (Rm != 0xF) {
1998     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1999     return MCDisassembler::Fail;
2000   }
2001 
2002   // First input register
2003   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2004     return MCDisassembler::Fail;
2005 
2006   // Second input register
2007   switch (Inst.getOpcode()) {
2008     case ARM::VST1q8:
2009     case ARM::VST1q16:
2010     case ARM::VST1q32:
2011     case ARM::VST1q64:
2012     case ARM::VST1q8_UPD:
2013     case ARM::VST1q16_UPD:
2014     case ARM::VST1q32_UPD:
2015     case ARM::VST1q64_UPD:
2016     case ARM::VST1d8T:
2017     case ARM::VST1d16T:
2018     case ARM::VST1d32T:
2019     case ARM::VST1d64T:
2020     case ARM::VST1d8T_UPD:
2021     case ARM::VST1d16T_UPD:
2022     case ARM::VST1d32T_UPD:
2023     case ARM::VST1d64T_UPD:
2024     case ARM::VST1d8Q:
2025     case ARM::VST1d16Q:
2026     case ARM::VST1d32Q:
2027     case ARM::VST1d64Q:
2028     case ARM::VST1d8Q_UPD:
2029     case ARM::VST1d16Q_UPD:
2030     case ARM::VST1d32Q_UPD:
2031     case ARM::VST1d64Q_UPD:
2032     case ARM::VST2d8:
2033     case ARM::VST2d16:
2034     case ARM::VST2d32:
2035     case ARM::VST2d8_UPD:
2036     case ARM::VST2d16_UPD:
2037     case ARM::VST2d32_UPD:
2038     case ARM::VST2q8:
2039     case ARM::VST2q16:
2040     case ARM::VST2q32:
2041     case ARM::VST2q8_UPD:
2042     case ARM::VST2q16_UPD:
2043     case ARM::VST2q32_UPD:
2044     case ARM::VST3d8:
2045     case ARM::VST3d16:
2046     case ARM::VST3d32:
2047     case ARM::VST3d8_UPD:
2048     case ARM::VST3d16_UPD:
2049     case ARM::VST3d32_UPD:
2050     case ARM::VST4d8:
2051     case ARM::VST4d16:
2052     case ARM::VST4d32:
2053     case ARM::VST4d8_UPD:
2054     case ARM::VST4d16_UPD:
2055     case ARM::VST4d32_UPD:
2056       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
2057         return MCDisassembler::Fail;
2058       break;
2059     case ARM::VST2b8:
2060     case ARM::VST2b16:
2061     case ARM::VST2b32:
2062     case ARM::VST2b8_UPD:
2063     case ARM::VST2b16_UPD:
2064     case ARM::VST2b32_UPD:
2065     case ARM::VST3q8:
2066     case ARM::VST3q16:
2067     case ARM::VST3q32:
2068     case ARM::VST3q8_UPD:
2069     case ARM::VST3q16_UPD:
2070     case ARM::VST3q32_UPD:
2071     case ARM::VST4q8:
2072     case ARM::VST4q16:
2073     case ARM::VST4q32:
2074     case ARM::VST4q8_UPD:
2075     case ARM::VST4q16_UPD:
2076     case ARM::VST4q32_UPD:
2077       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2078         return MCDisassembler::Fail;
2079       break;
2080     default:
2081       break;
2082   }
2083 
2084   // Third input register
2085   switch (Inst.getOpcode()) {
2086     case ARM::VST1d8T:
2087     case ARM::VST1d16T:
2088     case ARM::VST1d32T:
2089     case ARM::VST1d64T:
2090     case ARM::VST1d8T_UPD:
2091     case ARM::VST1d16T_UPD:
2092     case ARM::VST1d32T_UPD:
2093     case ARM::VST1d64T_UPD:
2094     case ARM::VST1d8Q:
2095     case ARM::VST1d16Q:
2096     case ARM::VST1d32Q:
2097     case ARM::VST1d64Q:
2098     case ARM::VST1d8Q_UPD:
2099     case ARM::VST1d16Q_UPD:
2100     case ARM::VST1d32Q_UPD:
2101     case ARM::VST1d64Q_UPD:
2102     case ARM::VST2q8:
2103     case ARM::VST2q16:
2104     case ARM::VST2q32:
2105     case ARM::VST2q8_UPD:
2106     case ARM::VST2q16_UPD:
2107     case ARM::VST2q32_UPD:
2108     case ARM::VST3d8:
2109     case ARM::VST3d16:
2110     case ARM::VST3d32:
2111     case ARM::VST3d8_UPD:
2112     case ARM::VST3d16_UPD:
2113     case ARM::VST3d32_UPD:
2114     case ARM::VST4d8:
2115     case ARM::VST4d16:
2116     case ARM::VST4d32:
2117     case ARM::VST4d8_UPD:
2118     case ARM::VST4d16_UPD:
2119     case ARM::VST4d32_UPD:
2120       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2121         return MCDisassembler::Fail;
2122       break;
2123     case ARM::VST3q8:
2124     case ARM::VST3q16:
2125     case ARM::VST3q32:
2126     case ARM::VST3q8_UPD:
2127     case ARM::VST3q16_UPD:
2128     case ARM::VST3q32_UPD:
2129     case ARM::VST4q8:
2130     case ARM::VST4q16:
2131     case ARM::VST4q32:
2132     case ARM::VST4q8_UPD:
2133     case ARM::VST4q16_UPD:
2134     case ARM::VST4q32_UPD:
2135       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
2136         return MCDisassembler::Fail;
2137       break;
2138     default:
2139       break;
2140   }
2141 
2142   // Fourth input register
2143   switch (Inst.getOpcode()) {
2144     case ARM::VST1d8Q:
2145     case ARM::VST1d16Q:
2146     case ARM::VST1d32Q:
2147     case ARM::VST1d64Q:
2148     case ARM::VST1d8Q_UPD:
2149     case ARM::VST1d16Q_UPD:
2150     case ARM::VST1d32Q_UPD:
2151     case ARM::VST1d64Q_UPD:
2152     case ARM::VST2q8:
2153     case ARM::VST2q16:
2154     case ARM::VST2q32:
2155     case ARM::VST2q8_UPD:
2156     case ARM::VST2q16_UPD:
2157     case ARM::VST2q32_UPD:
2158     case ARM::VST4d8:
2159     case ARM::VST4d16:
2160     case ARM::VST4d32:
2161     case ARM::VST4d8_UPD:
2162     case ARM::VST4d16_UPD:
2163     case ARM::VST4d32_UPD:
2164       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
2165         return MCDisassembler::Fail;
2166       break;
2167     case ARM::VST4q8:
2168     case ARM::VST4q16:
2169     case ARM::VST4q32:
2170     case ARM::VST4q8_UPD:
2171     case ARM::VST4q16_UPD:
2172     case ARM::VST4q32_UPD:
2173       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
2174         return MCDisassembler::Fail;
2175       break;
2176     default:
2177       break;
2178   }
2179 
2180   return S;
2181 }
2182 
2183 static DecodeStatus DecodeVLD1DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2184                                     uint64_t Address, const void *Decoder) {
2185   DecodeStatus S = MCDisassembler::Success;
2186 
2187   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2188   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2189   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2190   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2191   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2192   unsigned size = fieldFromInstruction32(Insn, 6, 2);
2193   unsigned regs = fieldFromInstruction32(Insn, 5, 1) + 1;
2194 
2195   align *= (1 << size);
2196 
2197   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2198     return MCDisassembler::Fail;
2199   if (regs == 2) {
2200     if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
2201       return MCDisassembler::Fail;
2202   }
2203   if (Rm != 0xF) {
2204     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2205       return MCDisassembler::Fail;
2206   }
2207 
2208   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2209     return MCDisassembler::Fail;
2210   Inst.addOperand(MCOperand::CreateImm(align));
2211 
2212   if (Rm == 0xD)
2213     Inst.addOperand(MCOperand::CreateReg(0));
2214   else if (Rm != 0xF) {
2215     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2216       return MCDisassembler::Fail;
2217   }
2218 
2219   return S;
2220 }
2221 
2222 static DecodeStatus DecodeVLD2DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2223                                     uint64_t Address, const void *Decoder) {
2224   DecodeStatus S = MCDisassembler::Success;
2225 
2226   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2227   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2228   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2229   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2230   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2231   unsigned size = 1 << fieldFromInstruction32(Insn, 6, 2);
2232   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2233   align *= 2*size;
2234 
2235   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2236     return MCDisassembler::Fail;
2237   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
2238     return MCDisassembler::Fail;
2239   if (Rm != 0xF) {
2240     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2241       return MCDisassembler::Fail;
2242   }
2243 
2244   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2245     return MCDisassembler::Fail;
2246   Inst.addOperand(MCOperand::CreateImm(align));
2247 
2248   if (Rm == 0xD)
2249     Inst.addOperand(MCOperand::CreateReg(0));
2250   else if (Rm != 0xF) {
2251     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2252       return MCDisassembler::Fail;
2253   }
2254 
2255   return S;
2256 }
2257 
2258 static DecodeStatus DecodeVLD3DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2259                                     uint64_t Address, const void *Decoder) {
2260   DecodeStatus S = MCDisassembler::Success;
2261 
2262   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2263   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2264   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2265   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2266   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
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 (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
2273     return MCDisassembler::Fail;
2274   if (Rm != 0xF) {
2275     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2276       return MCDisassembler::Fail;
2277   }
2278 
2279   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2280     return MCDisassembler::Fail;
2281   Inst.addOperand(MCOperand::CreateImm(0));
2282 
2283   if (Rm == 0xD)
2284     Inst.addOperand(MCOperand::CreateReg(0));
2285   else if (Rm != 0xF) {
2286     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2287       return MCDisassembler::Fail;
2288   }
2289 
2290   return S;
2291 }
2292 
2293 static DecodeStatus DecodeVLD4DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2294                                     uint64_t Address, const void *Decoder) {
2295   DecodeStatus S = MCDisassembler::Success;
2296 
2297   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2298   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2299   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2300   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2301   unsigned size = fieldFromInstruction32(Insn, 6, 2);
2302   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2303   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2304 
2305   if (size == 0x3) {
2306     size = 4;
2307     align = 16;
2308   } else {
2309     if (size == 2) {
2310       size = 1 << size;
2311       align *= 8;
2312     } else {
2313       size = 1 << size;
2314       align *= 4*size;
2315     }
2316   }
2317 
2318   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2319     return MCDisassembler::Fail;
2320   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
2321     return MCDisassembler::Fail;
2322   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
2323     return MCDisassembler::Fail;
2324   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3*inc)%32, Address, Decoder)))
2325     return MCDisassembler::Fail;
2326   if (Rm != 0xF) {
2327     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2328       return MCDisassembler::Fail;
2329   }
2330 
2331   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2332     return MCDisassembler::Fail;
2333   Inst.addOperand(MCOperand::CreateImm(align));
2334 
2335   if (Rm == 0xD)
2336     Inst.addOperand(MCOperand::CreateReg(0));
2337   else if (Rm != 0xF) {
2338     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2339       return MCDisassembler::Fail;
2340   }
2341 
2342   return S;
2343 }
2344 
2345 static DecodeStatus
2346 DecodeNEONModImmInstruction(llvm::MCInst &Inst, unsigned Insn,
2347                             uint64_t Address, const void *Decoder) {
2348   DecodeStatus S = MCDisassembler::Success;
2349 
2350   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2351   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2352   unsigned imm = fieldFromInstruction32(Insn, 0, 4);
2353   imm |= fieldFromInstruction32(Insn, 16, 3) << 4;
2354   imm |= fieldFromInstruction32(Insn, 24, 1) << 7;
2355   imm |= fieldFromInstruction32(Insn, 8, 4) << 8;
2356   imm |= fieldFromInstruction32(Insn, 5, 1) << 12;
2357   unsigned Q = fieldFromInstruction32(Insn, 6, 1);
2358 
2359   if (Q) {
2360     if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2361     return MCDisassembler::Fail;
2362   } else {
2363     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2364     return MCDisassembler::Fail;
2365   }
2366 
2367   Inst.addOperand(MCOperand::CreateImm(imm));
2368 
2369   switch (Inst.getOpcode()) {
2370     case ARM::VORRiv4i16:
2371     case ARM::VORRiv2i32:
2372     case ARM::VBICiv4i16:
2373     case ARM::VBICiv2i32:
2374       if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2375         return MCDisassembler::Fail;
2376       break;
2377     case ARM::VORRiv8i16:
2378     case ARM::VORRiv4i32:
2379     case ARM::VBICiv8i16:
2380     case ARM::VBICiv4i32:
2381       if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2382         return MCDisassembler::Fail;
2383       break;
2384     default:
2385       break;
2386   }
2387 
2388   return S;
2389 }
2390 
2391 static DecodeStatus DecodeVSHLMaxInstruction(llvm::MCInst &Inst, unsigned Insn,
2392                                         uint64_t Address, const void *Decoder) {
2393   DecodeStatus S = MCDisassembler::Success;
2394 
2395   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2396   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2397   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2398   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
2399   unsigned size = fieldFromInstruction32(Insn, 18, 2);
2400 
2401   if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2402     return MCDisassembler::Fail;
2403   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
2404     return MCDisassembler::Fail;
2405   Inst.addOperand(MCOperand::CreateImm(8 << size));
2406 
2407   return S;
2408 }
2409 
2410 static DecodeStatus DecodeShiftRight8Imm(llvm::MCInst &Inst, unsigned Val,
2411                                uint64_t Address, const void *Decoder) {
2412   Inst.addOperand(MCOperand::CreateImm(8 - Val));
2413   return MCDisassembler::Success;
2414 }
2415 
2416 static DecodeStatus DecodeShiftRight16Imm(llvm::MCInst &Inst, unsigned Val,
2417                                uint64_t Address, const void *Decoder) {
2418   Inst.addOperand(MCOperand::CreateImm(16 - Val));
2419   return MCDisassembler::Success;
2420 }
2421 
2422 static DecodeStatus DecodeShiftRight32Imm(llvm::MCInst &Inst, unsigned Val,
2423                                uint64_t Address, const void *Decoder) {
2424   Inst.addOperand(MCOperand::CreateImm(32 - Val));
2425   return MCDisassembler::Success;
2426 }
2427 
2428 static DecodeStatus DecodeShiftRight64Imm(llvm::MCInst &Inst, unsigned Val,
2429                                uint64_t Address, const void *Decoder) {
2430   Inst.addOperand(MCOperand::CreateImm(64 - Val));
2431   return MCDisassembler::Success;
2432 }
2433 
2434 static DecodeStatus DecodeTBLInstruction(llvm::MCInst &Inst, unsigned Insn,
2435                                uint64_t Address, const void *Decoder) {
2436   DecodeStatus S = MCDisassembler::Success;
2437 
2438   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2439   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2440   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2441   Rn |= fieldFromInstruction32(Insn, 7, 1) << 4;
2442   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2443   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
2444   unsigned op = fieldFromInstruction32(Insn, 6, 1);
2445   unsigned length = fieldFromInstruction32(Insn, 8, 2) + 1;
2446 
2447   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2448     return MCDisassembler::Fail;
2449   if (op) {
2450     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2451     return MCDisassembler::Fail; // Writeback
2452   }
2453 
2454   for (unsigned i = 0; i < length; ++i) {
2455     if (!Check(S, DecodeDPRRegisterClass(Inst, (Rn+i)%32, Address, Decoder)))
2456     return MCDisassembler::Fail;
2457   }
2458 
2459   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
2460     return MCDisassembler::Fail;
2461 
2462   return S;
2463 }
2464 
2465 static DecodeStatus DecodeVFPfpImm(llvm::MCInst &Inst, unsigned Val,
2466                             uint64_t Address, const void *Decoder) {
2467   // The immediate needs to be a fully instantiated float.  However, the
2468   // auto-generated decoder is only able to fill in some of the bits
2469   // necessary.  For instance, the 'b' bit is replicated multiple times,
2470   // and is even present in inverted form in one bit.  We do a little
2471   // binary parsing here to fill in those missing bits, and then
2472   // reinterpret it all as a float.
2473   union {
2474     uint32_t integer;
2475     float fp;
2476   } fp_conv;
2477 
2478   fp_conv.integer = Val;
2479   uint32_t b = fieldFromInstruction32(Val, 25, 1);
2480   fp_conv.integer |= b << 26;
2481   fp_conv.integer |= b << 27;
2482   fp_conv.integer |= b << 28;
2483   fp_conv.integer |= b << 29;
2484   fp_conv.integer |= (~b & 0x1) << 30;
2485 
2486   Inst.addOperand(MCOperand::CreateFPImm(fp_conv.fp));
2487   return MCDisassembler::Success;
2488 }
2489 
2490 static DecodeStatus DecodeThumbAddSpecialReg(llvm::MCInst &Inst, uint16_t Insn,
2491                                      uint64_t Address, const void *Decoder) {
2492   DecodeStatus S = MCDisassembler::Success;
2493 
2494   unsigned dst = fieldFromInstruction16(Insn, 8, 3);
2495   unsigned imm = fieldFromInstruction16(Insn, 0, 8);
2496 
2497   if (!Check(S, DecodetGPRRegisterClass(Inst, dst, Address, Decoder)))
2498     return MCDisassembler::Fail;
2499 
2500   switch(Inst.getOpcode()) {
2501     default:
2502       return MCDisassembler::Fail;
2503     case ARM::tADR:
2504       break; // tADR does not explicitly represent the PC as an operand.
2505     case ARM::tADDrSPi:
2506       Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2507       break;
2508   }
2509 
2510   Inst.addOperand(MCOperand::CreateImm(imm));
2511   return S;
2512 }
2513 
2514 static DecodeStatus DecodeThumbBROperand(llvm::MCInst &Inst, unsigned Val,
2515                                  uint64_t Address, const void *Decoder) {
2516   Inst.addOperand(MCOperand::CreateImm(SignExtend32<12>(Val << 1)));
2517   return MCDisassembler::Success;
2518 }
2519 
2520 static DecodeStatus DecodeT2BROperand(llvm::MCInst &Inst, unsigned Val,
2521                                  uint64_t Address, const void *Decoder) {
2522   Inst.addOperand(MCOperand::CreateImm(SignExtend32<21>(Val)));
2523   return MCDisassembler::Success;
2524 }
2525 
2526 static DecodeStatus DecodeThumbCmpBROperand(llvm::MCInst &Inst, unsigned Val,
2527                                  uint64_t Address, const void *Decoder) {
2528   Inst.addOperand(MCOperand::CreateImm(SignExtend32<7>(Val << 1)));
2529   return MCDisassembler::Success;
2530 }
2531 
2532 static DecodeStatus DecodeThumbAddrModeRR(llvm::MCInst &Inst, unsigned Val,
2533                                  uint64_t Address, const void *Decoder) {
2534   DecodeStatus S = MCDisassembler::Success;
2535 
2536   unsigned Rn = fieldFromInstruction32(Val, 0, 3);
2537   unsigned Rm = fieldFromInstruction32(Val, 3, 3);
2538 
2539   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
2540     return MCDisassembler::Fail;
2541   if (!Check(S, DecodetGPRRegisterClass(Inst, Rm, Address, Decoder)))
2542     return MCDisassembler::Fail;
2543 
2544   return S;
2545 }
2546 
2547 static DecodeStatus DecodeThumbAddrModeIS(llvm::MCInst &Inst, unsigned Val,
2548                                   uint64_t Address, const void *Decoder) {
2549   DecodeStatus S = MCDisassembler::Success;
2550 
2551   unsigned Rn = fieldFromInstruction32(Val, 0, 3);
2552   unsigned imm = fieldFromInstruction32(Val, 3, 5);
2553 
2554   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
2555     return MCDisassembler::Fail;
2556   Inst.addOperand(MCOperand::CreateImm(imm));
2557 
2558   return S;
2559 }
2560 
2561 static DecodeStatus DecodeThumbAddrModePC(llvm::MCInst &Inst, unsigned Val,
2562                                   uint64_t Address, const void *Decoder) {
2563   Inst.addOperand(MCOperand::CreateImm(Val << 2));
2564 
2565   return MCDisassembler::Success;
2566 }
2567 
2568 static DecodeStatus DecodeThumbAddrModeSP(llvm::MCInst &Inst, unsigned Val,
2569                                   uint64_t Address, const void *Decoder) {
2570   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2571   Inst.addOperand(MCOperand::CreateImm(Val));
2572 
2573   return MCDisassembler::Success;
2574 }
2575 
2576 static DecodeStatus DecodeT2AddrModeSOReg(llvm::MCInst &Inst, unsigned Val,
2577                                   uint64_t Address, const void *Decoder) {
2578   DecodeStatus S = MCDisassembler::Success;
2579 
2580   unsigned Rn = fieldFromInstruction32(Val, 6, 4);
2581   unsigned Rm = fieldFromInstruction32(Val, 2, 4);
2582   unsigned imm = fieldFromInstruction32(Val, 0, 2);
2583 
2584   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2585     return MCDisassembler::Fail;
2586   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
2587     return MCDisassembler::Fail;
2588   Inst.addOperand(MCOperand::CreateImm(imm));
2589 
2590   return S;
2591 }
2592 
2593 static DecodeStatus DecodeT2LoadShift(llvm::MCInst &Inst, unsigned Insn,
2594                               uint64_t Address, const void *Decoder) {
2595   DecodeStatus S = MCDisassembler::Success;
2596 
2597   switch (Inst.getOpcode()) {
2598     case ARM::t2PLDs:
2599     case ARM::t2PLDWs:
2600     case ARM::t2PLIs:
2601       break;
2602     default: {
2603       unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2604       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
2605     return MCDisassembler::Fail;
2606     }
2607   }
2608 
2609   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2610   if (Rn == 0xF) {
2611     switch (Inst.getOpcode()) {
2612       case ARM::t2LDRBs:
2613         Inst.setOpcode(ARM::t2LDRBpci);
2614         break;
2615       case ARM::t2LDRHs:
2616         Inst.setOpcode(ARM::t2LDRHpci);
2617         break;
2618       case ARM::t2LDRSHs:
2619         Inst.setOpcode(ARM::t2LDRSHpci);
2620         break;
2621       case ARM::t2LDRSBs:
2622         Inst.setOpcode(ARM::t2LDRSBpci);
2623         break;
2624       case ARM::t2PLDs:
2625         Inst.setOpcode(ARM::t2PLDi12);
2626         Inst.addOperand(MCOperand::CreateReg(ARM::PC));
2627         break;
2628       default:
2629         return MCDisassembler::Fail;
2630     }
2631 
2632     int imm = fieldFromInstruction32(Insn, 0, 12);
2633     if (!fieldFromInstruction32(Insn, 23, 1)) imm *= -1;
2634     Inst.addOperand(MCOperand::CreateImm(imm));
2635 
2636     return S;
2637   }
2638 
2639   unsigned addrmode = fieldFromInstruction32(Insn, 4, 2);
2640   addrmode |= fieldFromInstruction32(Insn, 0, 4) << 2;
2641   addrmode |= fieldFromInstruction32(Insn, 16, 4) << 6;
2642   if (!Check(S, DecodeT2AddrModeSOReg(Inst, addrmode, Address, Decoder)))
2643     return MCDisassembler::Fail;
2644 
2645   return S;
2646 }
2647 
2648 static DecodeStatus DecodeT2Imm8S4(llvm::MCInst &Inst, unsigned Val,
2649                            uint64_t Address, const void *Decoder) {
2650   int imm = Val & 0xFF;
2651   if (!(Val & 0x100)) imm *= -1;
2652   Inst.addOperand(MCOperand::CreateImm(imm << 2));
2653 
2654   return MCDisassembler::Success;
2655 }
2656 
2657 static DecodeStatus DecodeT2AddrModeImm8s4(llvm::MCInst &Inst, unsigned Val,
2658                                    uint64_t Address, const void *Decoder) {
2659   DecodeStatus S = MCDisassembler::Success;
2660 
2661   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
2662   unsigned imm = fieldFromInstruction32(Val, 0, 9);
2663 
2664   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2665     return MCDisassembler::Fail;
2666   if (!Check(S, DecodeT2Imm8S4(Inst, imm, Address, Decoder)))
2667     return MCDisassembler::Fail;
2668 
2669   return S;
2670 }
2671 
2672 static DecodeStatus DecodeT2Imm8(llvm::MCInst &Inst, unsigned Val,
2673                          uint64_t Address, const void *Decoder) {
2674   int imm = Val & 0xFF;
2675   if (!(Val & 0x100)) imm *= -1;
2676   Inst.addOperand(MCOperand::CreateImm(imm));
2677 
2678   return MCDisassembler::Success;
2679 }
2680 
2681 
2682 static DecodeStatus DecodeT2AddrModeImm8(llvm::MCInst &Inst, unsigned Val,
2683                                  uint64_t Address, const void *Decoder) {
2684   DecodeStatus S = MCDisassembler::Success;
2685 
2686   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
2687   unsigned imm = fieldFromInstruction32(Val, 0, 9);
2688 
2689   // Some instructions always use an additive offset.
2690   switch (Inst.getOpcode()) {
2691     case ARM::t2LDRT:
2692     case ARM::t2LDRBT:
2693     case ARM::t2LDRHT:
2694     case ARM::t2LDRSBT:
2695     case ARM::t2LDRSHT:
2696       imm |= 0x100;
2697       break;
2698     default:
2699       break;
2700   }
2701 
2702   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2703     return MCDisassembler::Fail;
2704   if (!Check(S, DecodeT2Imm8(Inst, imm, Address, Decoder)))
2705     return MCDisassembler::Fail;
2706 
2707   return S;
2708 }
2709 
2710 
2711 static DecodeStatus DecodeT2AddrModeImm12(llvm::MCInst &Inst, unsigned Val,
2712                                   uint64_t Address, const void *Decoder) {
2713   DecodeStatus S = MCDisassembler::Success;
2714 
2715   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
2716   unsigned imm = fieldFromInstruction32(Val, 0, 12);
2717 
2718   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2719     return MCDisassembler::Fail;
2720   Inst.addOperand(MCOperand::CreateImm(imm));
2721 
2722   return S;
2723 }
2724 
2725 
2726 static DecodeStatus DecodeThumbAddSPImm(llvm::MCInst &Inst, uint16_t Insn,
2727                                 uint64_t Address, const void *Decoder) {
2728   unsigned imm = fieldFromInstruction16(Insn, 0, 7);
2729 
2730   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2731   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2732   Inst.addOperand(MCOperand::CreateImm(imm));
2733 
2734   return MCDisassembler::Success;
2735 }
2736 
2737 static DecodeStatus DecodeThumbAddSPReg(llvm::MCInst &Inst, uint16_t Insn,
2738                                 uint64_t Address, const void *Decoder) {
2739   DecodeStatus S = MCDisassembler::Success;
2740 
2741   if (Inst.getOpcode() == ARM::tADDrSP) {
2742     unsigned Rdm = fieldFromInstruction16(Insn, 0, 3);
2743     Rdm |= fieldFromInstruction16(Insn, 7, 1) << 3;
2744 
2745     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
2746     return MCDisassembler::Fail;
2747     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
2748     return MCDisassembler::Fail;
2749     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2750   } else if (Inst.getOpcode() == ARM::tADDspr) {
2751     unsigned Rm = fieldFromInstruction16(Insn, 3, 4);
2752 
2753     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2754     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2755     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2756     return MCDisassembler::Fail;
2757   }
2758 
2759   return S;
2760 }
2761 
2762 static DecodeStatus DecodeThumbCPS(llvm::MCInst &Inst, uint16_t Insn,
2763                            uint64_t Address, const void *Decoder) {
2764   unsigned imod = fieldFromInstruction16(Insn, 4, 1) | 0x2;
2765   unsigned flags = fieldFromInstruction16(Insn, 0, 3);
2766 
2767   Inst.addOperand(MCOperand::CreateImm(imod));
2768   Inst.addOperand(MCOperand::CreateImm(flags));
2769 
2770   return MCDisassembler::Success;
2771 }
2772 
2773 static DecodeStatus DecodePostIdxReg(llvm::MCInst &Inst, unsigned Insn,
2774                              uint64_t Address, const void *Decoder) {
2775   DecodeStatus S = MCDisassembler::Success;
2776   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2777   unsigned add = fieldFromInstruction32(Insn, 4, 1);
2778 
2779   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2780     return MCDisassembler::Fail;
2781   Inst.addOperand(MCOperand::CreateImm(add));
2782 
2783   return S;
2784 }
2785 
2786 static DecodeStatus DecodeThumbBLXOffset(llvm::MCInst &Inst, unsigned Val,
2787                                  uint64_t Address, const void *Decoder) {
2788   Inst.addOperand(MCOperand::CreateImm(SignExtend32<22>(Val << 1)));
2789   return MCDisassembler::Success;
2790 }
2791 
2792 static DecodeStatus DecodeCoprocessor(llvm::MCInst &Inst, unsigned Val,
2793                               uint64_t Address, const void *Decoder) {
2794   if (Val == 0xA || Val == 0xB)
2795     return MCDisassembler::Fail;
2796 
2797   Inst.addOperand(MCOperand::CreateImm(Val));
2798   return MCDisassembler::Success;
2799 }
2800 
2801 static DecodeStatus
2802 DecodeThumb2BCCInstruction(llvm::MCInst &Inst, unsigned Insn,
2803                            uint64_t Address, const void *Decoder) {
2804   DecodeStatus S = MCDisassembler::Success;
2805 
2806   unsigned pred = fieldFromInstruction32(Insn, 22, 4);
2807   if (pred == 0xE || pred == 0xF) {
2808     unsigned opc = fieldFromInstruction32(Insn, 4, 28);
2809     switch (opc) {
2810       default:
2811         return MCDisassembler::Fail;
2812       case 0xf3bf8f4:
2813         Inst.setOpcode(ARM::t2DSB);
2814         break;
2815       case 0xf3bf8f5:
2816         Inst.setOpcode(ARM::t2DMB);
2817         break;
2818       case 0xf3bf8f6:
2819         Inst.setOpcode(ARM::t2ISB);
2820         break;
2821     }
2822 
2823     unsigned imm = fieldFromInstruction32(Insn, 0, 4);
2824     return DecodeMemBarrierOption(Inst, imm, Address, Decoder);
2825   }
2826 
2827   unsigned brtarget = fieldFromInstruction32(Insn, 0, 11) << 1;
2828   brtarget |= fieldFromInstruction32(Insn, 11, 1) << 19;
2829   brtarget |= fieldFromInstruction32(Insn, 13, 1) << 18;
2830   brtarget |= fieldFromInstruction32(Insn, 16, 6) << 12;
2831   brtarget |= fieldFromInstruction32(Insn, 26, 1) << 20;
2832 
2833   if (!Check(S, DecodeT2BROperand(Inst, brtarget, Address, Decoder)))
2834     return MCDisassembler::Fail;
2835   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2836     return MCDisassembler::Fail;
2837 
2838   return S;
2839 }
2840 
2841 // Decode a shifted immediate operand.  These basically consist
2842 // of an 8-bit value, and a 4-bit directive that specifies either
2843 // a splat operation or a rotation.
2844 static DecodeStatus DecodeT2SOImm(llvm::MCInst &Inst, unsigned Val,
2845                           uint64_t Address, const void *Decoder) {
2846   unsigned ctrl = fieldFromInstruction32(Val, 10, 2);
2847   if (ctrl == 0) {
2848     unsigned byte = fieldFromInstruction32(Val, 8, 2);
2849     unsigned imm = fieldFromInstruction32(Val, 0, 8);
2850     switch (byte) {
2851       case 0:
2852         Inst.addOperand(MCOperand::CreateImm(imm));
2853         break;
2854       case 1:
2855         Inst.addOperand(MCOperand::CreateImm((imm << 16) | imm));
2856         break;
2857       case 2:
2858         Inst.addOperand(MCOperand::CreateImm((imm << 24) | (imm << 8)));
2859         break;
2860       case 3:
2861         Inst.addOperand(MCOperand::CreateImm((imm << 24) | (imm << 16) |
2862                                              (imm << 8)  |  imm));
2863         break;
2864     }
2865   } else {
2866     unsigned unrot = fieldFromInstruction32(Val, 0, 7) | 0x80;
2867     unsigned rot = fieldFromInstruction32(Val, 7, 5);
2868     unsigned imm = (unrot >> rot) | (unrot << ((32-rot)&31));
2869     Inst.addOperand(MCOperand::CreateImm(imm));
2870   }
2871 
2872   return MCDisassembler::Success;
2873 }
2874 
2875 static DecodeStatus
2876 DecodeThumbBCCTargetOperand(llvm::MCInst &Inst, unsigned Val,
2877                             uint64_t Address, const void *Decoder){
2878   Inst.addOperand(MCOperand::CreateImm(Val << 1));
2879   return MCDisassembler::Success;
2880 }
2881 
2882 static DecodeStatus DecodeThumbBLTargetOperand(llvm::MCInst &Inst, unsigned Val,
2883                                        uint64_t Address, const void *Decoder){
2884   Inst.addOperand(MCOperand::CreateImm(SignExtend32<22>(Val << 1)));
2885   return MCDisassembler::Success;
2886 }
2887 
2888 static DecodeStatus DecodeMemBarrierOption(llvm::MCInst &Inst, unsigned Val,
2889                                    uint64_t Address, const void *Decoder) {
2890   switch (Val) {
2891   default:
2892     return MCDisassembler::Fail;
2893   case 0xF: // SY
2894   case 0xE: // ST
2895   case 0xB: // ISH
2896   case 0xA: // ISHST
2897   case 0x7: // NSH
2898   case 0x6: // NSHST
2899   case 0x3: // OSH
2900   case 0x2: // OSHST
2901     break;
2902   }
2903 
2904   Inst.addOperand(MCOperand::CreateImm(Val));
2905   return MCDisassembler::Success;
2906 }
2907 
2908 static DecodeStatus DecodeMSRMask(llvm::MCInst &Inst, unsigned Val,
2909                           uint64_t Address, const void *Decoder) {
2910   if (!Val) return MCDisassembler::Fail;
2911   Inst.addOperand(MCOperand::CreateImm(Val));
2912   return MCDisassembler::Success;
2913 }
2914 
2915 static DecodeStatus DecodeDoubleRegLoad(llvm::MCInst &Inst, unsigned Insn,
2916                                         uint64_t Address, const void *Decoder) {
2917   DecodeStatus S = MCDisassembler::Success;
2918 
2919   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2920   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2921   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
2922 
2923   if ((Rt & 1) || Rt == 0xE || Rn == 0xF) return MCDisassembler::Fail;
2924 
2925   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
2926     return MCDisassembler::Fail;
2927   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
2928     return MCDisassembler::Fail;
2929   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2930     return MCDisassembler::Fail;
2931   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2932     return MCDisassembler::Fail;
2933 
2934   return S;
2935 }
2936 
2937 
2938 static DecodeStatus DecodeDoubleRegStore(llvm::MCInst &Inst, unsigned Insn,
2939                                          uint64_t Address, const void *Decoder){
2940   DecodeStatus S = MCDisassembler::Success;
2941 
2942   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2943   unsigned Rt = fieldFromInstruction32(Insn, 0, 4);
2944   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2945   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
2946 
2947   if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
2948     return MCDisassembler::Fail;
2949 
2950   if ((Rt & 1) || Rt == 0xE || Rn == 0xF) return MCDisassembler::Fail;
2951   if (Rd == Rn || Rd == Rt || Rd == Rt+1) return MCDisassembler::Fail;
2952 
2953   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
2954     return MCDisassembler::Fail;
2955   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
2956     return MCDisassembler::Fail;
2957   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2958     return MCDisassembler::Fail;
2959   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2960     return MCDisassembler::Fail;
2961 
2962   return S;
2963 }
2964 
2965 static DecodeStatus DecodeLDRPreImm(llvm::MCInst &Inst, unsigned Insn,
2966                             uint64_t Address, const void *Decoder) {
2967   DecodeStatus S = MCDisassembler::Success;
2968 
2969   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2970   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2971   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
2972   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
2973   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
2974   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
2975 
2976   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
2977 
2978   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
2979     return MCDisassembler::Fail;
2980   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2981     return MCDisassembler::Fail;
2982   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
2983     return MCDisassembler::Fail;
2984   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2985     return MCDisassembler::Fail;
2986 
2987   return S;
2988 }
2989 
2990 static DecodeStatus DecodeLDRPreReg(llvm::MCInst &Inst, unsigned Insn,
2991                             uint64_t Address, const void *Decoder) {
2992   DecodeStatus S = MCDisassembler::Success;
2993 
2994   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2995   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2996   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
2997   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
2998   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
2999   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3000   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3001 
3002   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3003   if (Rm == 0xF) S = MCDisassembler::SoftFail;
3004 
3005   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3006     return MCDisassembler::Fail;
3007   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3008     return MCDisassembler::Fail;
3009   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
3010     return MCDisassembler::Fail;
3011   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3012     return MCDisassembler::Fail;
3013 
3014   return S;
3015 }
3016 
3017 
3018 static DecodeStatus DecodeSTRPreImm(llvm::MCInst &Inst, unsigned Insn,
3019                             uint64_t Address, const void *Decoder) {
3020   DecodeStatus S = MCDisassembler::Success;
3021 
3022   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3023   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3024   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3025   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3026   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3027   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3028 
3029   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3030 
3031   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3032     return MCDisassembler::Fail;
3033   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3034     return MCDisassembler::Fail;
3035   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
3036     return MCDisassembler::Fail;
3037   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3038     return MCDisassembler::Fail;
3039 
3040   return S;
3041 }
3042 
3043 static DecodeStatus DecodeSTRPreReg(llvm::MCInst &Inst, unsigned Insn,
3044                             uint64_t Address, const void *Decoder) {
3045   DecodeStatus S = MCDisassembler::Success;
3046 
3047   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3048   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3049   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3050   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3051   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3052   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3053 
3054   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3055 
3056   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3057     return MCDisassembler::Fail;
3058   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3059     return MCDisassembler::Fail;
3060   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
3061     return MCDisassembler::Fail;
3062   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3063     return MCDisassembler::Fail;
3064 
3065   return S;
3066 }
3067 
3068 static DecodeStatus DecodeVLD1LN(llvm::MCInst &Inst, unsigned Insn,
3069                          uint64_t Address, const void *Decoder) {
3070   DecodeStatus S = MCDisassembler::Success;
3071 
3072   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3073   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3074   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3075   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3076   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3077 
3078   unsigned align = 0;
3079   unsigned index = 0;
3080   switch (size) {
3081     default:
3082       return MCDisassembler::Fail;
3083     case 0:
3084       if (fieldFromInstruction32(Insn, 4, 1))
3085         return MCDisassembler::Fail; // UNDEFINED
3086       index = fieldFromInstruction32(Insn, 5, 3);
3087       break;
3088     case 1:
3089       if (fieldFromInstruction32(Insn, 5, 1))
3090         return MCDisassembler::Fail; // UNDEFINED
3091       index = fieldFromInstruction32(Insn, 6, 2);
3092       if (fieldFromInstruction32(Insn, 4, 1))
3093         align = 2;
3094       break;
3095     case 2:
3096       if (fieldFromInstruction32(Insn, 6, 1))
3097         return MCDisassembler::Fail; // UNDEFINED
3098       index = fieldFromInstruction32(Insn, 7, 1);
3099       if (fieldFromInstruction32(Insn, 4, 2) != 0)
3100         align = 4;
3101   }
3102 
3103   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3104     return MCDisassembler::Fail;
3105   if (Rm != 0xF) { // Writeback
3106     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3107       return MCDisassembler::Fail;
3108   }
3109   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3110     return MCDisassembler::Fail;
3111   Inst.addOperand(MCOperand::CreateImm(align));
3112   if (Rm != 0xF) {
3113     if (Rm != 0xD) {
3114       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3115         return MCDisassembler::Fail;
3116     } else
3117       Inst.addOperand(MCOperand::CreateReg(0));
3118   }
3119 
3120   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3121     return MCDisassembler::Fail;
3122   Inst.addOperand(MCOperand::CreateImm(index));
3123 
3124   return S;
3125 }
3126 
3127 static DecodeStatus DecodeVST1LN(llvm::MCInst &Inst, unsigned Insn,
3128                          uint64_t Address, const void *Decoder) {
3129   DecodeStatus S = MCDisassembler::Success;
3130 
3131   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3132   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3133   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3134   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3135   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3136 
3137   unsigned align = 0;
3138   unsigned index = 0;
3139   switch (size) {
3140     default:
3141       return MCDisassembler::Fail;
3142     case 0:
3143       if (fieldFromInstruction32(Insn, 4, 1))
3144         return MCDisassembler::Fail; // UNDEFINED
3145       index = fieldFromInstruction32(Insn, 5, 3);
3146       break;
3147     case 1:
3148       if (fieldFromInstruction32(Insn, 5, 1))
3149         return MCDisassembler::Fail; // UNDEFINED
3150       index = fieldFromInstruction32(Insn, 6, 2);
3151       if (fieldFromInstruction32(Insn, 4, 1))
3152         align = 2;
3153       break;
3154     case 2:
3155       if (fieldFromInstruction32(Insn, 6, 1))
3156         return MCDisassembler::Fail; // UNDEFINED
3157       index = fieldFromInstruction32(Insn, 7, 1);
3158       if (fieldFromInstruction32(Insn, 4, 2) != 0)
3159         align = 4;
3160   }
3161 
3162   if (Rm != 0xF) { // Writeback
3163     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3164     return MCDisassembler::Fail;
3165   }
3166   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3167     return MCDisassembler::Fail;
3168   Inst.addOperand(MCOperand::CreateImm(align));
3169   if (Rm != 0xF) {
3170     if (Rm != 0xD) {
3171       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3172     return MCDisassembler::Fail;
3173     } else
3174       Inst.addOperand(MCOperand::CreateReg(0));
3175   }
3176 
3177   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3178     return MCDisassembler::Fail;
3179   Inst.addOperand(MCOperand::CreateImm(index));
3180 
3181   return S;
3182 }
3183 
3184 
3185 static DecodeStatus DecodeVLD2LN(llvm::MCInst &Inst, unsigned Insn,
3186                          uint64_t Address, const void *Decoder) {
3187   DecodeStatus S = MCDisassembler::Success;
3188 
3189   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3190   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3191   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3192   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3193   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3194 
3195   unsigned align = 0;
3196   unsigned index = 0;
3197   unsigned inc = 1;
3198   switch (size) {
3199     default:
3200       return MCDisassembler::Fail;
3201     case 0:
3202       index = fieldFromInstruction32(Insn, 5, 3);
3203       if (fieldFromInstruction32(Insn, 4, 1))
3204         align = 2;
3205       break;
3206     case 1:
3207       index = fieldFromInstruction32(Insn, 6, 2);
3208       if (fieldFromInstruction32(Insn, 4, 1))
3209         align = 4;
3210       if (fieldFromInstruction32(Insn, 5, 1))
3211         inc = 2;
3212       break;
3213     case 2:
3214       if (fieldFromInstruction32(Insn, 5, 1))
3215         return MCDisassembler::Fail; // UNDEFINED
3216       index = fieldFromInstruction32(Insn, 7, 1);
3217       if (fieldFromInstruction32(Insn, 4, 1) != 0)
3218         align = 8;
3219       if (fieldFromInstruction32(Insn, 6, 1))
3220         inc = 2;
3221       break;
3222   }
3223 
3224   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3225     return MCDisassembler::Fail;
3226   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3227     return MCDisassembler::Fail;
3228   if (Rm != 0xF) { // Writeback
3229     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3230       return MCDisassembler::Fail;
3231   }
3232   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3233     return MCDisassembler::Fail;
3234   Inst.addOperand(MCOperand::CreateImm(align));
3235   if (Rm != 0xF) {
3236     if (Rm != 0xD) {
3237       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3238         return MCDisassembler::Fail;
3239     } else
3240       Inst.addOperand(MCOperand::CreateReg(0));
3241   }
3242 
3243   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3244     return MCDisassembler::Fail;
3245   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3246     return MCDisassembler::Fail;
3247   Inst.addOperand(MCOperand::CreateImm(index));
3248 
3249   return S;
3250 }
3251 
3252 static DecodeStatus DecodeVST2LN(llvm::MCInst &Inst, unsigned Insn,
3253                          uint64_t Address, const void *Decoder) {
3254   DecodeStatus S = MCDisassembler::Success;
3255 
3256   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3257   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3258   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3259   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3260   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3261 
3262   unsigned align = 0;
3263   unsigned index = 0;
3264   unsigned inc = 1;
3265   switch (size) {
3266     default:
3267       return MCDisassembler::Fail;
3268     case 0:
3269       index = fieldFromInstruction32(Insn, 5, 3);
3270       if (fieldFromInstruction32(Insn, 4, 1))
3271         align = 2;
3272       break;
3273     case 1:
3274       index = fieldFromInstruction32(Insn, 6, 2);
3275       if (fieldFromInstruction32(Insn, 4, 1))
3276         align = 4;
3277       if (fieldFromInstruction32(Insn, 5, 1))
3278         inc = 2;
3279       break;
3280     case 2:
3281       if (fieldFromInstruction32(Insn, 5, 1))
3282         return MCDisassembler::Fail; // UNDEFINED
3283       index = fieldFromInstruction32(Insn, 7, 1);
3284       if (fieldFromInstruction32(Insn, 4, 1) != 0)
3285         align = 8;
3286       if (fieldFromInstruction32(Insn, 6, 1))
3287         inc = 2;
3288       break;
3289   }
3290 
3291   if (Rm != 0xF) { // Writeback
3292     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3293       return MCDisassembler::Fail;
3294   }
3295   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3296     return MCDisassembler::Fail;
3297   Inst.addOperand(MCOperand::CreateImm(align));
3298   if (Rm != 0xF) {
3299     if (Rm != 0xD) {
3300       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3301         return MCDisassembler::Fail;
3302     } else
3303       Inst.addOperand(MCOperand::CreateReg(0));
3304   }
3305 
3306   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3307     return MCDisassembler::Fail;
3308   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3309     return MCDisassembler::Fail;
3310   Inst.addOperand(MCOperand::CreateImm(index));
3311 
3312   return S;
3313 }
3314 
3315 
3316 static DecodeStatus DecodeVLD3LN(llvm::MCInst &Inst, unsigned Insn,
3317                          uint64_t Address, const void *Decoder) {
3318   DecodeStatus S = MCDisassembler::Success;
3319 
3320   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3321   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3322   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3323   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3324   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3325 
3326   unsigned align = 0;
3327   unsigned index = 0;
3328   unsigned inc = 1;
3329   switch (size) {
3330     default:
3331       return MCDisassembler::Fail;
3332     case 0:
3333       if (fieldFromInstruction32(Insn, 4, 1))
3334         return MCDisassembler::Fail; // UNDEFINED
3335       index = fieldFromInstruction32(Insn, 5, 3);
3336       break;
3337     case 1:
3338       if (fieldFromInstruction32(Insn, 4, 1))
3339         return MCDisassembler::Fail; // UNDEFINED
3340       index = fieldFromInstruction32(Insn, 6, 2);
3341       if (fieldFromInstruction32(Insn, 5, 1))
3342         inc = 2;
3343       break;
3344     case 2:
3345       if (fieldFromInstruction32(Insn, 4, 2))
3346         return MCDisassembler::Fail; // UNDEFINED
3347       index = fieldFromInstruction32(Insn, 7, 1);
3348       if (fieldFromInstruction32(Insn, 6, 1))
3349         inc = 2;
3350       break;
3351   }
3352 
3353   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3354     return MCDisassembler::Fail;
3355   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3356     return MCDisassembler::Fail;
3357   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3358     return MCDisassembler::Fail;
3359 
3360   if (Rm != 0xF) { // Writeback
3361     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3362     return MCDisassembler::Fail;
3363   }
3364   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3365     return MCDisassembler::Fail;
3366   Inst.addOperand(MCOperand::CreateImm(align));
3367   if (Rm != 0xF) {
3368     if (Rm != 0xD) {
3369       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3370     return MCDisassembler::Fail;
3371     } else
3372       Inst.addOperand(MCOperand::CreateReg(0));
3373   }
3374 
3375   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3376     return MCDisassembler::Fail;
3377   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3378     return MCDisassembler::Fail;
3379   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3380     return MCDisassembler::Fail;
3381   Inst.addOperand(MCOperand::CreateImm(index));
3382 
3383   return S;
3384 }
3385 
3386 static DecodeStatus DecodeVST3LN(llvm::MCInst &Inst, unsigned Insn,
3387                          uint64_t Address, const void *Decoder) {
3388   DecodeStatus S = MCDisassembler::Success;
3389 
3390   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3391   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3392   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3393   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3394   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3395 
3396   unsigned align = 0;
3397   unsigned index = 0;
3398   unsigned inc = 1;
3399   switch (size) {
3400     default:
3401       return MCDisassembler::Fail;
3402     case 0:
3403       if (fieldFromInstruction32(Insn, 4, 1))
3404         return MCDisassembler::Fail; // UNDEFINED
3405       index = fieldFromInstruction32(Insn, 5, 3);
3406       break;
3407     case 1:
3408       if (fieldFromInstruction32(Insn, 4, 1))
3409         return MCDisassembler::Fail; // UNDEFINED
3410       index = fieldFromInstruction32(Insn, 6, 2);
3411       if (fieldFromInstruction32(Insn, 5, 1))
3412         inc = 2;
3413       break;
3414     case 2:
3415       if (fieldFromInstruction32(Insn, 4, 2))
3416         return MCDisassembler::Fail; // UNDEFINED
3417       index = fieldFromInstruction32(Insn, 7, 1);
3418       if (fieldFromInstruction32(Insn, 6, 1))
3419         inc = 2;
3420       break;
3421   }
3422 
3423   if (Rm != 0xF) { // Writeback
3424     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3425     return MCDisassembler::Fail;
3426   }
3427   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3428     return MCDisassembler::Fail;
3429   Inst.addOperand(MCOperand::CreateImm(align));
3430   if (Rm != 0xF) {
3431     if (Rm != 0xD) {
3432       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3433     return MCDisassembler::Fail;
3434     } else
3435       Inst.addOperand(MCOperand::CreateReg(0));
3436   }
3437 
3438   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3439     return MCDisassembler::Fail;
3440   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3441     return MCDisassembler::Fail;
3442   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3443     return MCDisassembler::Fail;
3444   Inst.addOperand(MCOperand::CreateImm(index));
3445 
3446   return S;
3447 }
3448 
3449 
3450 static DecodeStatus DecodeVLD4LN(llvm::MCInst &Inst, unsigned Insn,
3451                          uint64_t Address, const void *Decoder) {
3452   DecodeStatus S = MCDisassembler::Success;
3453 
3454   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3455   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3456   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3457   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3458   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3459 
3460   unsigned align = 0;
3461   unsigned index = 0;
3462   unsigned inc = 1;
3463   switch (size) {
3464     default:
3465       return MCDisassembler::Fail;
3466     case 0:
3467       if (fieldFromInstruction32(Insn, 4, 1))
3468         align = 4;
3469       index = fieldFromInstruction32(Insn, 5, 3);
3470       break;
3471     case 1:
3472       if (fieldFromInstruction32(Insn, 4, 1))
3473         align = 8;
3474       index = fieldFromInstruction32(Insn, 6, 2);
3475       if (fieldFromInstruction32(Insn, 5, 1))
3476         inc = 2;
3477       break;
3478     case 2:
3479       if (fieldFromInstruction32(Insn, 4, 2))
3480         align = 4 << fieldFromInstruction32(Insn, 4, 2);
3481       index = fieldFromInstruction32(Insn, 7, 1);
3482       if (fieldFromInstruction32(Insn, 6, 1))
3483         inc = 2;
3484       break;
3485   }
3486 
3487   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3488     return MCDisassembler::Fail;
3489   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3490     return MCDisassembler::Fail;
3491   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3492     return MCDisassembler::Fail;
3493   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
3494     return MCDisassembler::Fail;
3495 
3496   if (Rm != 0xF) { // Writeback
3497     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3498       return MCDisassembler::Fail;
3499   }
3500   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3501     return MCDisassembler::Fail;
3502   Inst.addOperand(MCOperand::CreateImm(align));
3503   if (Rm != 0xF) {
3504     if (Rm != 0xD) {
3505       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3506         return MCDisassembler::Fail;
3507     } else
3508       Inst.addOperand(MCOperand::CreateReg(0));
3509   }
3510 
3511   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3512     return MCDisassembler::Fail;
3513   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3514     return MCDisassembler::Fail;
3515   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3516     return MCDisassembler::Fail;
3517   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
3518     return MCDisassembler::Fail;
3519   Inst.addOperand(MCOperand::CreateImm(index));
3520 
3521   return S;
3522 }
3523 
3524 static DecodeStatus DecodeVST4LN(llvm::MCInst &Inst, unsigned Insn,
3525                          uint64_t Address, const void *Decoder) {
3526   DecodeStatus S = MCDisassembler::Success;
3527 
3528   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3529   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3530   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3531   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3532   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3533 
3534   unsigned align = 0;
3535   unsigned index = 0;
3536   unsigned inc = 1;
3537   switch (size) {
3538     default:
3539       return MCDisassembler::Fail;
3540     case 0:
3541       if (fieldFromInstruction32(Insn, 4, 1))
3542         align = 4;
3543       index = fieldFromInstruction32(Insn, 5, 3);
3544       break;
3545     case 1:
3546       if (fieldFromInstruction32(Insn, 4, 1))
3547         align = 8;
3548       index = fieldFromInstruction32(Insn, 6, 2);
3549       if (fieldFromInstruction32(Insn, 5, 1))
3550         inc = 2;
3551       break;
3552     case 2:
3553       if (fieldFromInstruction32(Insn, 4, 2))
3554         align = 4 << fieldFromInstruction32(Insn, 4, 2);
3555       index = fieldFromInstruction32(Insn, 7, 1);
3556       if (fieldFromInstruction32(Insn, 6, 1))
3557         inc = 2;
3558       break;
3559   }
3560 
3561   if (Rm != 0xF) { // Writeback
3562     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3563     return MCDisassembler::Fail;
3564   }
3565   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3566     return MCDisassembler::Fail;
3567   Inst.addOperand(MCOperand::CreateImm(align));
3568   if (Rm != 0xF) {
3569     if (Rm != 0xD) {
3570       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3571     return MCDisassembler::Fail;
3572     } else
3573       Inst.addOperand(MCOperand::CreateReg(0));
3574   }
3575 
3576   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3577     return MCDisassembler::Fail;
3578   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3579     return MCDisassembler::Fail;
3580   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3581     return MCDisassembler::Fail;
3582   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
3583     return MCDisassembler::Fail;
3584   Inst.addOperand(MCOperand::CreateImm(index));
3585 
3586   return S;
3587 }
3588 
3589 static DecodeStatus DecodeVMOVSRR(llvm::MCInst &Inst, unsigned Insn,
3590                                   uint64_t Address, const void *Decoder) {
3591   DecodeStatus S = MCDisassembler::Success;
3592   unsigned Rt  = fieldFromInstruction32(Insn, 12, 4);
3593   unsigned Rt2 = fieldFromInstruction32(Insn, 16, 4);
3594   unsigned Rm  = fieldFromInstruction32(Insn,  0, 4);
3595   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3596   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
3597 
3598   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
3599     S = MCDisassembler::SoftFail;
3600 
3601   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
3602     return MCDisassembler::Fail;
3603   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
3604     return MCDisassembler::Fail;
3605   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
3606     return MCDisassembler::Fail;
3607   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
3608     return MCDisassembler::Fail;
3609   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3610     return MCDisassembler::Fail;
3611 
3612   return S;
3613 }
3614 
3615 static DecodeStatus DecodeVMOVRRS(llvm::MCInst &Inst, unsigned Insn,
3616                                   uint64_t Address, const void *Decoder) {
3617   DecodeStatus S = MCDisassembler::Success;
3618   unsigned Rt  = fieldFromInstruction32(Insn, 12, 4);
3619   unsigned Rt2 = fieldFromInstruction32(Insn, 16, 4);
3620   unsigned Rm  = fieldFromInstruction32(Insn,  0, 4);
3621   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3622   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
3623 
3624   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
3625     S = MCDisassembler::SoftFail;
3626 
3627   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
3628     return MCDisassembler::Fail;
3629   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
3630     return MCDisassembler::Fail;
3631   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
3632     return MCDisassembler::Fail;
3633   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
3634     return MCDisassembler::Fail;
3635   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3636     return MCDisassembler::Fail;
3637 
3638   return S;
3639 }
3640 
3641 static DecodeStatus DecodeIT(llvm::MCInst &Inst, unsigned Insn,
3642                              uint64_t Address, const void *Decoder) {
3643   DecodeStatus S = MCDisassembler::Success;
3644   unsigned pred = fieldFromInstruction16(Insn, 4, 4);
3645   // The InstPrinter needs to have the low bit of the predicate in
3646   // the mask operand to be able to print it properly.
3647   unsigned mask = fieldFromInstruction16(Insn, 0, 5);
3648 
3649   if (pred == 0xF) {
3650     pred = 0xE;
3651     S = MCDisassembler::SoftFail;
3652   }
3653 
3654   if ((mask & 0xF) == 0) {
3655     // Preserve the high bit of the mask, which is the low bit of
3656     // the predicate.
3657     mask &= 0x10;
3658     mask |= 0x8;
3659     S = MCDisassembler::SoftFail;
3660   }
3661 
3662   Inst.addOperand(MCOperand::CreateImm(pred));
3663   Inst.addOperand(MCOperand::CreateImm(mask));
3664   return S;
3665 }
3666 
3667 static DecodeStatus
3668 DecodeT2LDRDPreInstruction(llvm::MCInst &Inst, unsigned Insn,
3669                            uint64_t Address, const void *Decoder) {
3670   DecodeStatus S = MCDisassembler::Success;
3671 
3672   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3673   unsigned Rt2 = fieldFromInstruction32(Insn, 8, 4);
3674   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3675   unsigned addr = fieldFromInstruction32(Insn, 0, 8);
3676   unsigned W = fieldFromInstruction32(Insn, 21, 1);
3677   unsigned U = fieldFromInstruction32(Insn, 23, 1);
3678   unsigned P = fieldFromInstruction32(Insn, 24, 1);
3679   bool writeback = (W == 1) | (P == 0);
3680 
3681   addr |= (U << 8) | (Rn << 9);
3682 
3683   if (writeback && (Rn == Rt || Rn == Rt2))
3684     Check(S, MCDisassembler::SoftFail);
3685   if (Rt == Rt2)
3686     Check(S, MCDisassembler::SoftFail);
3687 
3688   // Rt
3689   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
3690     return MCDisassembler::Fail;
3691   // Rt2
3692   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
3693     return MCDisassembler::Fail;
3694   // Writeback operand
3695   if (!Check(S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
3696     return MCDisassembler::Fail;
3697   // addr
3698   if (!Check(S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
3699     return MCDisassembler::Fail;
3700 
3701   return S;
3702 }
3703 
3704 static DecodeStatus
3705 DecodeT2STRDPreInstruction(llvm::MCInst &Inst, unsigned Insn,
3706                            uint64_t Address, const void *Decoder) {
3707   DecodeStatus S = MCDisassembler::Success;
3708 
3709   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3710   unsigned Rt2 = fieldFromInstruction32(Insn, 8, 4);
3711   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3712   unsigned addr = fieldFromInstruction32(Insn, 0, 8);
3713   unsigned W = fieldFromInstruction32(Insn, 21, 1);
3714   unsigned U = fieldFromInstruction32(Insn, 23, 1);
3715   unsigned P = fieldFromInstruction32(Insn, 24, 1);
3716   bool writeback = (W == 1) | (P == 0);
3717 
3718   addr |= (U << 8) | (Rn << 9);
3719 
3720   if (writeback && (Rn == Rt || Rn == Rt2))
3721     Check(S, MCDisassembler::SoftFail);
3722 
3723   // Writeback operand
3724   if (!Check(S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
3725     return MCDisassembler::Fail;
3726   // Rt
3727   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
3728     return MCDisassembler::Fail;
3729   // Rt2
3730   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
3731     return MCDisassembler::Fail;
3732   // addr
3733   if (!Check(S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
3734     return MCDisassembler::Fail;
3735 
3736   return S;
3737 }
3738