xref: /llvm-project/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp (revision 8067df95039024cdec2c890b69d8af5722958089)
1 //===- ARMDisassembler.cpp - Disassembler for ARM/Thumb ISA -----*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #define DEBUG_TYPE "arm-disassembler"
11 
12 #include "ARM.h"
13 #include "ARMRegisterInfo.h"
14 #include "ARMSubtarget.h"
15 #include "MCTargetDesc/ARMAddressingModes.h"
16 #include "MCTargetDesc/ARMBaseInfo.h"
17 #include "llvm/MC/EDInstInfo.h"
18 #include "llvm/MC/MCInst.h"
19 #include "llvm/MC/MCExpr.h"
20 #include "llvm/MC/MCContext.h"
21 #include "llvm/MC/MCDisassembler.h"
22 #include "llvm/Support/Debug.h"
23 #include "llvm/Support/MemoryObject.h"
24 #include "llvm/Support/ErrorHandling.h"
25 #include "llvm/Support/TargetRegistry.h"
26 #include "llvm/Support/raw_ostream.h"
27 
28 using namespace llvm;
29 
30 typedef MCDisassembler::DecodeStatus DecodeStatus;
31 
32 namespace {
33 /// ARMDisassembler - ARM disassembler for all ARM platforms.
34 class ARMDisassembler : public MCDisassembler {
35 public:
36   /// Constructor     - Initializes the disassembler.
37   ///
38   ARMDisassembler(const MCSubtargetInfo &STI) :
39     MCDisassembler(STI) {
40   }
41 
42   ~ARMDisassembler() {
43   }
44 
45   /// getInstruction - See MCDisassembler.
46   DecodeStatus getInstruction(MCInst &instr,
47                               uint64_t &size,
48                               const MemoryObject &region,
49                               uint64_t address,
50                               raw_ostream &vStream) const;
51 
52   /// getEDInfo - See MCDisassembler.
53   EDInstInfo *getEDInfo() const;
54 private:
55 };
56 
57 /// ThumbDisassembler - Thumb disassembler for all Thumb platforms.
58 class ThumbDisassembler : public MCDisassembler {
59 public:
60   /// Constructor     - Initializes the disassembler.
61   ///
62   ThumbDisassembler(const MCSubtargetInfo &STI) :
63     MCDisassembler(STI) {
64   }
65 
66   ~ThumbDisassembler() {
67   }
68 
69   /// getInstruction - See MCDisassembler.
70   DecodeStatus getInstruction(MCInst &instr,
71                               uint64_t &size,
72                               const MemoryObject &region,
73                               uint64_t address,
74                               raw_ostream &vStream) const;
75 
76   /// getEDInfo - See MCDisassembler.
77   EDInstInfo *getEDInfo() const;
78 private:
79   mutable std::vector<unsigned> ITBlock;
80   void AddThumbPredicate(MCInst&) const;
81   void UpdateThumbVFPPredicate(MCInst&) const;
82 };
83 }
84 
85 static bool Check(DecodeStatus &Out, DecodeStatus In) {
86   switch (In) {
87     case MCDisassembler::Success:
88       // Out stays the same.
89       return true;
90     case MCDisassembler::SoftFail:
91       Out = In;
92       return true;
93     case MCDisassembler::Fail:
94       Out = In;
95       return false;
96   }
97   return false;
98 }
99 
100 
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 
297 #include "ARMGenDisassemblerTables.inc"
298 #include "ARMGenInstrInfo.inc"
299 #include "ARMGenEDInfo.inc"
300 
301 static MCDisassembler *createARMDisassembler(const Target &T, const MCSubtargetInfo &STI) {
302   return new ARMDisassembler(STI);
303 }
304 
305 static MCDisassembler *createThumbDisassembler(const Target &T, const MCSubtargetInfo &STI) {
306   return new ThumbDisassembler(STI);
307 }
308 
309 EDInstInfo *ARMDisassembler::getEDInfo() const {
310   return instInfoARM;
311 }
312 
313 EDInstInfo *ThumbDisassembler::getEDInfo() const {
314   return instInfoARM;
315 }
316 
317 DecodeStatus ARMDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
318                                              const MemoryObject &Region,
319                                              uint64_t Address,
320                                              raw_ostream &os) const {
321   uint8_t bytes[4];
322 
323   assert(!(STI.getFeatureBits() & ARM::ModeThumb) &&
324          "Asked to disassemble an ARM instruction but Subtarget is in Thumb mode!");
325 
326   // We want to read exactly 4 bytes of data.
327   if (Region.readBytes(Address, 4, (uint8_t*)bytes, NULL) == -1) {
328     Size = 0;
329     return MCDisassembler::Fail;
330   }
331 
332   // Encoded as a small-endian 32-bit word in the stream.
333   uint32_t insn = (bytes[3] << 24) |
334                   (bytes[2] << 16) |
335                   (bytes[1] <<  8) |
336                   (bytes[0] <<  0);
337 
338   // Calling the auto-generated decoder function.
339   DecodeStatus result = decodeARMInstruction32(MI, insn, Address, this, STI);
340   if (result != MCDisassembler::Fail) {
341     Size = 4;
342     return result;
343   }
344 
345   // Instructions that are shared between ARM and Thumb modes.
346   // FIXME: This shouldn't really exist.  It's an artifact of the
347   // fact that we fail to encode a few instructions properly for Thumb.
348   MI.clear();
349   result = decodeCommonInstruction32(MI, insn, Address, this, STI);
350   if (result != MCDisassembler::Fail) {
351     Size = 4;
352     return result;
353   }
354 
355   // VFP and NEON instructions, similarly, are shared between ARM
356   // and Thumb modes.
357   MI.clear();
358   result = decodeVFPInstruction32(MI, insn, Address, this, STI);
359   if (result != MCDisassembler::Fail) {
360     Size = 4;
361     return result;
362   }
363 
364   MI.clear();
365   result = decodeNEONDataInstruction32(MI, insn, Address, this, STI);
366   if (result != MCDisassembler::Fail) {
367     Size = 4;
368     // Add a fake predicate operand, because we share these instruction
369     // definitions with Thumb2 where these instructions are predicable.
370     if (!DecodePredicateOperand(MI, 0xE, Address, this))
371       return MCDisassembler::Fail;
372     return result;
373   }
374 
375   MI.clear();
376   result = decodeNEONLoadStoreInstruction32(MI, insn, Address, this, STI);
377   if (result != MCDisassembler::Fail) {
378     Size = 4;
379     // Add a fake predicate operand, because we share these instruction
380     // definitions with Thumb2 where these instructions are predicable.
381     if (!DecodePredicateOperand(MI, 0xE, Address, this))
382       return MCDisassembler::Fail;
383     return result;
384   }
385 
386   MI.clear();
387   result = decodeNEONDupInstruction32(MI, insn, Address, this, STI);
388   if (result != MCDisassembler::Fail) {
389     Size = 4;
390     // Add a fake predicate operand, because we share these instruction
391     // definitions with Thumb2 where these instructions are predicable.
392     if (!DecodePredicateOperand(MI, 0xE, Address, this))
393       return MCDisassembler::Fail;
394     return result;
395   }
396 
397   MI.clear();
398 
399   Size = 0;
400   return MCDisassembler::Fail;
401 }
402 
403 namespace llvm {
404 extern MCInstrDesc ARMInsts[];
405 }
406 
407 // Thumb1 instructions don't have explicit S bits.  Rather, they
408 // implicitly set CPSR.  Since it's not represented in the encoding, the
409 // auto-generated decoder won't inject the CPSR operand.  We need to fix
410 // that as a post-pass.
411 static void AddThumb1SBit(MCInst &MI, bool InITBlock) {
412   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
413   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
414   MCInst::iterator I = MI.begin();
415   for (unsigned i = 0; i < NumOps; ++i, ++I) {
416     if (I == MI.end()) break;
417     if (OpInfo[i].isOptionalDef() && OpInfo[i].RegClass == ARM::CCRRegClassID) {
418       if (i > 0 && OpInfo[i-1].isPredicate()) continue;
419       MI.insert(I, MCOperand::CreateReg(InITBlock ? 0 : ARM::CPSR));
420       return;
421     }
422   }
423 
424   MI.insert(I, MCOperand::CreateReg(InITBlock ? 0 : ARM::CPSR));
425 }
426 
427 // Most Thumb instructions don't have explicit predicates in the
428 // encoding, but rather get their predicates from IT context.  We need
429 // to fix up the predicate operands using this context information as a
430 // post-pass.
431 void ThumbDisassembler::AddThumbPredicate(MCInst &MI) const {
432   // A few instructions actually have predicates encoded in them.  Don't
433   // try to overwrite it if we're seeing one of those.
434   switch (MI.getOpcode()) {
435     case ARM::tBcc:
436     case ARM::t2Bcc:
437       return;
438     default:
439       break;
440   }
441 
442   // If we're in an IT block, base the predicate on that.  Otherwise,
443   // assume a predicate of AL.
444   unsigned CC;
445   if (!ITBlock.empty()) {
446     CC = ITBlock.back();
447     if (CC == 0xF)
448       CC = ARMCC::AL;
449     ITBlock.pop_back();
450   } else
451     CC = ARMCC::AL;
452 
453   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
454   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
455   MCInst::iterator I = MI.begin();
456   for (unsigned i = 0; i < NumOps; ++i, ++I) {
457     if (I == MI.end()) break;
458     if (OpInfo[i].isPredicate()) {
459       I = MI.insert(I, MCOperand::CreateImm(CC));
460       ++I;
461       if (CC == ARMCC::AL)
462         MI.insert(I, MCOperand::CreateReg(0));
463       else
464         MI.insert(I, MCOperand::CreateReg(ARM::CPSR));
465       return;
466     }
467   }
468 
469   I = MI.insert(I, MCOperand::CreateImm(CC));
470   ++I;
471   if (CC == ARMCC::AL)
472     MI.insert(I, MCOperand::CreateReg(0));
473   else
474     MI.insert(I, MCOperand::CreateReg(ARM::CPSR));
475 }
476 
477 // Thumb VFP instructions are a special case.  Because we share their
478 // encodings between ARM and Thumb modes, and they are predicable in ARM
479 // mode, the auto-generated decoder will give them an (incorrect)
480 // predicate operand.  We need to rewrite these operands based on the IT
481 // context as a post-pass.
482 void ThumbDisassembler::UpdateThumbVFPPredicate(MCInst &MI) const {
483   unsigned CC;
484   if (!ITBlock.empty()) {
485     CC = ITBlock.back();
486     ITBlock.pop_back();
487   } else
488     CC = ARMCC::AL;
489 
490   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
491   MCInst::iterator I = MI.begin();
492   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
493   for (unsigned i = 0; i < NumOps; ++i, ++I) {
494     if (OpInfo[i].isPredicate() ) {
495       I->setImm(CC);
496       ++I;
497       if (CC == ARMCC::AL)
498         I->setReg(0);
499       else
500         I->setReg(ARM::CPSR);
501       return;
502     }
503   }
504 }
505 
506 DecodeStatus ThumbDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
507                                                const MemoryObject &Region,
508                                                uint64_t Address,
509                                                raw_ostream &os) const {
510   uint8_t bytes[4];
511 
512   assert((STI.getFeatureBits() & ARM::ModeThumb) &&
513          "Asked to disassemble in Thumb mode but Subtarget is in ARM mode!");
514 
515   // We want to read exactly 2 bytes of data.
516   if (Region.readBytes(Address, 2, (uint8_t*)bytes, NULL) == -1) {
517     Size = 0;
518     return MCDisassembler::Fail;
519   }
520 
521   uint16_t insn16 = (bytes[1] << 8) | bytes[0];
522   DecodeStatus result = decodeThumbInstruction16(MI, insn16, Address, this, STI);
523   if (result != MCDisassembler::Fail) {
524     Size = 2;
525     AddThumbPredicate(MI);
526     return result;
527   }
528 
529   MI.clear();
530   result = decodeThumbSBitInstruction16(MI, insn16, Address, this, STI);
531   if (result) {
532     Size = 2;
533     bool InITBlock = !ITBlock.empty();
534     AddThumbPredicate(MI);
535     AddThumb1SBit(MI, InITBlock);
536     return result;
537   }
538 
539   MI.clear();
540   result = decodeThumb2Instruction16(MI, insn16, Address, this, STI);
541   if (result != MCDisassembler::Fail) {
542     Size = 2;
543     AddThumbPredicate(MI);
544 
545     // If we find an IT instruction, we need to parse its condition
546     // code and mask operands so that we can apply them correctly
547     // to the subsequent instructions.
548     if (MI.getOpcode() == ARM::t2IT) {
549       // (3 - the number of trailing zeros) is the number of then / else.
550       unsigned firstcond = MI.getOperand(0).getImm();
551       unsigned Mask = MI.getOperand(1).getImm();
552       unsigned CondBit0 = Mask >> 4 & 1;
553       unsigned NumTZ = CountTrailingZeros_32(Mask);
554       assert(NumTZ <= 3 && "Invalid IT mask!");
555       for (unsigned Pos = 3, e = NumTZ; Pos > e; --Pos) {
556         bool T = ((Mask >> Pos) & 1) == CondBit0;
557         if (T)
558           ITBlock.insert(ITBlock.begin(), firstcond);
559         else
560           ITBlock.insert(ITBlock.begin(), firstcond ^ 1);
561       }
562 
563       ITBlock.push_back(firstcond);
564     }
565 
566     return result;
567   }
568 
569   // We want to read exactly 4 bytes of data.
570   if (Region.readBytes(Address, 4, (uint8_t*)bytes, NULL) == -1) {
571     Size = 0;
572     return MCDisassembler::Fail;
573   }
574 
575   uint32_t insn32 = (bytes[3] <<  8) |
576                     (bytes[2] <<  0) |
577                     (bytes[1] << 24) |
578                     (bytes[0] << 16);
579   MI.clear();
580   result = decodeThumbInstruction32(MI, insn32, Address, this, STI);
581   if (result != MCDisassembler::Fail) {
582     Size = 4;
583     bool InITBlock = ITBlock.size();
584     AddThumbPredicate(MI);
585     AddThumb1SBit(MI, InITBlock);
586     return result;
587   }
588 
589   MI.clear();
590   result = decodeThumb2Instruction32(MI, insn32, Address, this, STI);
591   if (result != MCDisassembler::Fail) {
592     Size = 4;
593     AddThumbPredicate(MI);
594     return result;
595   }
596 
597   MI.clear();
598   result = decodeCommonInstruction32(MI, insn32, Address, this, STI);
599   if (result != MCDisassembler::Fail) {
600     Size = 4;
601     AddThumbPredicate(MI);
602     return result;
603   }
604 
605   MI.clear();
606   result = decodeVFPInstruction32(MI, insn32, Address, this, STI);
607   if (result != MCDisassembler::Fail) {
608     Size = 4;
609     UpdateThumbVFPPredicate(MI);
610     return result;
611   }
612 
613   MI.clear();
614   result = decodeNEONDupInstruction32(MI, insn32, Address, this, STI);
615   if (result != MCDisassembler::Fail) {
616     Size = 4;
617     AddThumbPredicate(MI);
618     return result;
619   }
620 
621   if (fieldFromInstruction32(insn32, 24, 8) == 0xF9) {
622     MI.clear();
623     uint32_t NEONLdStInsn = insn32;
624     NEONLdStInsn &= 0xF0FFFFFF;
625     NEONLdStInsn |= 0x04000000;
626     result = decodeNEONLoadStoreInstruction32(MI, NEONLdStInsn, Address, this, STI);
627     if (result != MCDisassembler::Fail) {
628       Size = 4;
629       AddThumbPredicate(MI);
630       return result;
631     }
632   }
633 
634   if (fieldFromInstruction32(insn32, 24, 4) == 0xF) {
635     MI.clear();
636     uint32_t NEONDataInsn = insn32;
637     NEONDataInsn &= 0xF0FFFFFF; // Clear bits 27-24
638     NEONDataInsn |= (NEONDataInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
639     NEONDataInsn |= 0x12000000; // Set bits 28 and 25
640     result = decodeNEONDataInstruction32(MI, NEONDataInsn, Address, this, STI);
641     if (result != MCDisassembler::Fail) {
642       Size = 4;
643       AddThumbPredicate(MI);
644       return result;
645     }
646   }
647 
648   Size = 0;
649   return MCDisassembler::Fail;
650 }
651 
652 
653 extern "C" void LLVMInitializeARMDisassembler() {
654   TargetRegistry::RegisterMCDisassembler(TheARMTarget,
655                                          createARMDisassembler);
656   TargetRegistry::RegisterMCDisassembler(TheThumbTarget,
657                                          createThumbDisassembler);
658 }
659 
660 static const unsigned GPRDecoderTable[] = {
661   ARM::R0, ARM::R1, ARM::R2, ARM::R3,
662   ARM::R4, ARM::R5, ARM::R6, ARM::R7,
663   ARM::R8, ARM::R9, ARM::R10, ARM::R11,
664   ARM::R12, ARM::SP, ARM::LR, ARM::PC
665 };
666 
667 static DecodeStatus DecodeGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
668                                    uint64_t Address, const void *Decoder) {
669   if (RegNo > 15)
670     return MCDisassembler::Fail;
671 
672   unsigned Register = GPRDecoderTable[RegNo];
673   Inst.addOperand(MCOperand::CreateReg(Register));
674   return MCDisassembler::Success;
675 }
676 
677 static DecodeStatus
678 DecodeGPRnopcRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
679                            uint64_t Address, const void *Decoder) {
680   if (RegNo == 15) return MCDisassembler::Fail;
681   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
682 }
683 
684 static DecodeStatus DecodetGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
685                                    uint64_t Address, const void *Decoder) {
686   if (RegNo > 7)
687     return MCDisassembler::Fail;
688   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
689 }
690 
691 static DecodeStatus DecodetcGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
692                                    uint64_t Address, const void *Decoder) {
693   unsigned Register = 0;
694   switch (RegNo) {
695     case 0:
696       Register = ARM::R0;
697       break;
698     case 1:
699       Register = ARM::R1;
700       break;
701     case 2:
702       Register = ARM::R2;
703       break;
704     case 3:
705       Register = ARM::R3;
706       break;
707     case 9:
708       Register = ARM::R9;
709       break;
710     case 12:
711       Register = ARM::R12;
712       break;
713     default:
714       return MCDisassembler::Fail;
715     }
716 
717   Inst.addOperand(MCOperand::CreateReg(Register));
718   return MCDisassembler::Success;
719 }
720 
721 static DecodeStatus DecoderGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
722                                    uint64_t Address, const void *Decoder) {
723   if (RegNo == 13 || RegNo == 15) return MCDisassembler::Fail;
724   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
725 }
726 
727 static const unsigned SPRDecoderTable[] = {
728      ARM::S0,  ARM::S1,  ARM::S2,  ARM::S3,
729      ARM::S4,  ARM::S5,  ARM::S6,  ARM::S7,
730      ARM::S8,  ARM::S9, ARM::S10, ARM::S11,
731     ARM::S12, ARM::S13, ARM::S14, ARM::S15,
732     ARM::S16, ARM::S17, ARM::S18, ARM::S19,
733     ARM::S20, ARM::S21, ARM::S22, ARM::S23,
734     ARM::S24, ARM::S25, ARM::S26, ARM::S27,
735     ARM::S28, ARM::S29, ARM::S30, ARM::S31
736 };
737 
738 static DecodeStatus DecodeSPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
739                                    uint64_t Address, const void *Decoder) {
740   if (RegNo > 31)
741     return MCDisassembler::Fail;
742 
743   unsigned Register = SPRDecoderTable[RegNo];
744   Inst.addOperand(MCOperand::CreateReg(Register));
745   return MCDisassembler::Success;
746 }
747 
748 static const unsigned DPRDecoderTable[] = {
749      ARM::D0,  ARM::D1,  ARM::D2,  ARM::D3,
750      ARM::D4,  ARM::D5,  ARM::D6,  ARM::D7,
751      ARM::D8,  ARM::D9, ARM::D10, ARM::D11,
752     ARM::D12, ARM::D13, ARM::D14, ARM::D15,
753     ARM::D16, ARM::D17, ARM::D18, ARM::D19,
754     ARM::D20, ARM::D21, ARM::D22, ARM::D23,
755     ARM::D24, ARM::D25, ARM::D26, ARM::D27,
756     ARM::D28, ARM::D29, ARM::D30, ARM::D31
757 };
758 
759 static DecodeStatus DecodeDPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
760                                    uint64_t Address, const void *Decoder) {
761   if (RegNo > 31)
762     return MCDisassembler::Fail;
763 
764   unsigned Register = DPRDecoderTable[RegNo];
765   Inst.addOperand(MCOperand::CreateReg(Register));
766   return MCDisassembler::Success;
767 }
768 
769 static DecodeStatus DecodeDPR_8RegisterClass(llvm::MCInst &Inst, unsigned RegNo,
770                                    uint64_t Address, const void *Decoder) {
771   if (RegNo > 7)
772     return MCDisassembler::Fail;
773   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
774 }
775 
776 static DecodeStatus
777 DecodeDPR_VFP2RegisterClass(llvm::MCInst &Inst, unsigned RegNo,
778                             uint64_t Address, const void *Decoder) {
779   if (RegNo > 15)
780     return MCDisassembler::Fail;
781   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
782 }
783 
784 static const unsigned QPRDecoderTable[] = {
785      ARM::Q0,  ARM::Q1,  ARM::Q2,  ARM::Q3,
786      ARM::Q4,  ARM::Q5,  ARM::Q6,  ARM::Q7,
787      ARM::Q8,  ARM::Q9, ARM::Q10, ARM::Q11,
788     ARM::Q12, ARM::Q13, ARM::Q14, ARM::Q15
789 };
790 
791 
792 static DecodeStatus DecodeQPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
793                                    uint64_t Address, const void *Decoder) {
794   if (RegNo > 31)
795     return MCDisassembler::Fail;
796   RegNo >>= 1;
797 
798   unsigned Register = QPRDecoderTable[RegNo];
799   Inst.addOperand(MCOperand::CreateReg(Register));
800   return MCDisassembler::Success;
801 }
802 
803 static DecodeStatus DecodePredicateOperand(llvm::MCInst &Inst, unsigned Val,
804                                uint64_t Address, const void *Decoder) {
805   if (Val == 0xF) return MCDisassembler::Fail;
806   // AL predicate is not allowed on Thumb1 branches.
807   if (Inst.getOpcode() == ARM::tBcc && Val == 0xE)
808     return MCDisassembler::Fail;
809   Inst.addOperand(MCOperand::CreateImm(Val));
810   if (Val == ARMCC::AL) {
811     Inst.addOperand(MCOperand::CreateReg(0));
812   } else
813     Inst.addOperand(MCOperand::CreateReg(ARM::CPSR));
814   return MCDisassembler::Success;
815 }
816 
817 static DecodeStatus DecodeCCOutOperand(llvm::MCInst &Inst, unsigned Val,
818                                uint64_t Address, const void *Decoder) {
819   if (Val)
820     Inst.addOperand(MCOperand::CreateReg(ARM::CPSR));
821   else
822     Inst.addOperand(MCOperand::CreateReg(0));
823   return MCDisassembler::Success;
824 }
825 
826 static DecodeStatus DecodeSOImmOperand(llvm::MCInst &Inst, unsigned Val,
827                                uint64_t Address, const void *Decoder) {
828   uint32_t imm = Val & 0xFF;
829   uint32_t rot = (Val & 0xF00) >> 7;
830   uint32_t rot_imm = (imm >> rot) | (imm << (32-rot));
831   Inst.addOperand(MCOperand::CreateImm(rot_imm));
832   return MCDisassembler::Success;
833 }
834 
835 static DecodeStatus DecodeSORegImmOperand(llvm::MCInst &Inst, unsigned Val,
836                                uint64_t Address, const void *Decoder) {
837   DecodeStatus S = MCDisassembler::Success;
838 
839   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
840   unsigned type = fieldFromInstruction32(Val, 5, 2);
841   unsigned imm = fieldFromInstruction32(Val, 7, 5);
842 
843   // Register-immediate
844   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
845     return MCDisassembler::Fail;
846 
847   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
848   switch (type) {
849     case 0:
850       Shift = ARM_AM::lsl;
851       break;
852     case 1:
853       Shift = ARM_AM::lsr;
854       break;
855     case 2:
856       Shift = ARM_AM::asr;
857       break;
858     case 3:
859       Shift = ARM_AM::ror;
860       break;
861   }
862 
863   if (Shift == ARM_AM::ror && imm == 0)
864     Shift = ARM_AM::rrx;
865 
866   unsigned Op = Shift | (imm << 3);
867   Inst.addOperand(MCOperand::CreateImm(Op));
868 
869   return S;
870 }
871 
872 static DecodeStatus DecodeSORegRegOperand(llvm::MCInst &Inst, unsigned Val,
873                                uint64_t Address, const void *Decoder) {
874   DecodeStatus S = MCDisassembler::Success;
875 
876   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
877   unsigned type = fieldFromInstruction32(Val, 5, 2);
878   unsigned Rs = fieldFromInstruction32(Val, 8, 4);
879 
880   // Register-register
881   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
882     return MCDisassembler::Fail;
883   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rs, Address, Decoder)))
884     return MCDisassembler::Fail;
885 
886   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
887   switch (type) {
888     case 0:
889       Shift = ARM_AM::lsl;
890       break;
891     case 1:
892       Shift = ARM_AM::lsr;
893       break;
894     case 2:
895       Shift = ARM_AM::asr;
896       break;
897     case 3:
898       Shift = ARM_AM::ror;
899       break;
900   }
901 
902   Inst.addOperand(MCOperand::CreateImm(Shift));
903 
904   return S;
905 }
906 
907 static DecodeStatus DecodeRegListOperand(llvm::MCInst &Inst, unsigned Val,
908                                  uint64_t Address, const void *Decoder) {
909   DecodeStatus S = MCDisassembler::Success;
910 
911   // Empty register lists are not allowed.
912   if (CountPopulation_32(Val) == 0) return MCDisassembler::Fail;
913   for (unsigned i = 0; i < 16; ++i) {
914     if (Val & (1 << i)) {
915       if (!Check(S, DecodeGPRRegisterClass(Inst, i, Address, Decoder)))
916         return MCDisassembler::Fail;
917     }
918   }
919 
920   return S;
921 }
922 
923 static DecodeStatus DecodeSPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
924                                  uint64_t Address, const void *Decoder) {
925   DecodeStatus S = MCDisassembler::Success;
926 
927   unsigned Vd = fieldFromInstruction32(Val, 8, 4);
928   unsigned regs = Val & 0xFF;
929 
930   if (!Check(S, DecodeSPRRegisterClass(Inst, Vd, Address, Decoder)))
931     return MCDisassembler::Fail;
932   for (unsigned i = 0; i < (regs - 1); ++i) {
933     if (!Check(S, DecodeSPRRegisterClass(Inst, ++Vd, Address, Decoder)))
934       return MCDisassembler::Fail;
935   }
936 
937   return S;
938 }
939 
940 static DecodeStatus DecodeDPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
941                                  uint64_t Address, const void *Decoder) {
942   DecodeStatus S = MCDisassembler::Success;
943 
944   unsigned Vd = fieldFromInstruction32(Val, 8, 4);
945   unsigned regs = (Val & 0xFF) / 2;
946 
947   if (!Check(S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)))
948       return MCDisassembler::Fail;
949   for (unsigned i = 0; i < (regs - 1); ++i) {
950     if (!Check(S, DecodeDPRRegisterClass(Inst, ++Vd, Address, Decoder)))
951       return MCDisassembler::Fail;
952   }
953 
954   return S;
955 }
956 
957 static DecodeStatus DecodeBitfieldMaskOperand(llvm::MCInst &Inst, unsigned Val,
958                                       uint64_t Address, const void *Decoder) {
959   // This operand encodes a mask of contiguous zeros between a specified MSB
960   // and LSB.  To decode it, we create the mask of all bits MSB-and-lower,
961   // the mask of all bits LSB-and-lower, and then xor them to create
962   // the mask of that's all ones on [msb, lsb].  Finally we not it to
963   // create the final mask.
964   unsigned msb = fieldFromInstruction32(Val, 5, 5);
965   unsigned lsb = fieldFromInstruction32(Val, 0, 5);
966   uint32_t msb_mask = (1 << (msb+1)) - 1;
967   uint32_t lsb_mask = (1 << lsb) - 1;
968   Inst.addOperand(MCOperand::CreateImm(~(msb_mask ^ lsb_mask)));
969   return MCDisassembler::Success;
970 }
971 
972 static DecodeStatus DecodeCopMemInstruction(llvm::MCInst &Inst, unsigned Insn,
973                                   uint64_t Address, const void *Decoder) {
974   DecodeStatus S = MCDisassembler::Success;
975 
976   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
977   unsigned CRd = fieldFromInstruction32(Insn, 12, 4);
978   unsigned coproc = fieldFromInstruction32(Insn, 8, 4);
979   unsigned imm = fieldFromInstruction32(Insn, 0, 8);
980   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
981   unsigned U = fieldFromInstruction32(Insn, 23, 1);
982 
983   switch (Inst.getOpcode()) {
984     case ARM::LDC_OFFSET:
985     case ARM::LDC_PRE:
986     case ARM::LDC_POST:
987     case ARM::LDC_OPTION:
988     case ARM::LDCL_OFFSET:
989     case ARM::LDCL_PRE:
990     case ARM::LDCL_POST:
991     case ARM::LDCL_OPTION:
992     case ARM::STC_OFFSET:
993     case ARM::STC_PRE:
994     case ARM::STC_POST:
995     case ARM::STC_OPTION:
996     case ARM::STCL_OFFSET:
997     case ARM::STCL_PRE:
998     case ARM::STCL_POST:
999     case ARM::STCL_OPTION:
1000       if (coproc == 0xA || coproc == 0xB)
1001         return MCDisassembler::Fail;
1002       break;
1003     default:
1004       break;
1005   }
1006 
1007   Inst.addOperand(MCOperand::CreateImm(coproc));
1008   Inst.addOperand(MCOperand::CreateImm(CRd));
1009   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1010     return MCDisassembler::Fail;
1011   switch (Inst.getOpcode()) {
1012     case ARM::LDC_OPTION:
1013     case ARM::LDCL_OPTION:
1014     case ARM::LDC2_OPTION:
1015     case ARM::LDC2L_OPTION:
1016     case ARM::STC_OPTION:
1017     case ARM::STCL_OPTION:
1018     case ARM::STC2_OPTION:
1019     case ARM::STC2L_OPTION:
1020     case ARM::LDCL_POST:
1021     case ARM::STCL_POST:
1022     case ARM::LDC2L_POST:
1023     case ARM::STC2L_POST:
1024       break;
1025     default:
1026       Inst.addOperand(MCOperand::CreateReg(0));
1027       break;
1028   }
1029 
1030   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1031   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1032 
1033   bool writeback = (P == 0) || (W == 1);
1034   unsigned idx_mode = 0;
1035   if (P && writeback)
1036     idx_mode = ARMII::IndexModePre;
1037   else if (!P && writeback)
1038     idx_mode = ARMII::IndexModePost;
1039 
1040   switch (Inst.getOpcode()) {
1041     case ARM::LDCL_POST:
1042     case ARM::STCL_POST:
1043     case ARM::LDC2L_POST:
1044     case ARM::STC2L_POST:
1045       imm |= U << 8;
1046     case ARM::LDC_OPTION:
1047     case ARM::LDCL_OPTION:
1048     case ARM::LDC2_OPTION:
1049     case ARM::LDC2L_OPTION:
1050     case ARM::STC_OPTION:
1051     case ARM::STCL_OPTION:
1052     case ARM::STC2_OPTION:
1053     case ARM::STC2L_OPTION:
1054       Inst.addOperand(MCOperand::CreateImm(imm));
1055       break;
1056     default:
1057       if (U)
1058         Inst.addOperand(MCOperand::CreateImm(
1059             ARM_AM::getAM2Opc(ARM_AM::add, imm, ARM_AM::lsl, idx_mode)));
1060       else
1061         Inst.addOperand(MCOperand::CreateImm(
1062             ARM_AM::getAM2Opc(ARM_AM::sub, imm, ARM_AM::lsl, idx_mode)));
1063       break;
1064   }
1065 
1066   switch (Inst.getOpcode()) {
1067     case ARM::LDC_OFFSET:
1068     case ARM::LDC_PRE:
1069     case ARM::LDC_POST:
1070     case ARM::LDC_OPTION:
1071     case ARM::LDCL_OFFSET:
1072     case ARM::LDCL_PRE:
1073     case ARM::LDCL_POST:
1074     case ARM::LDCL_OPTION:
1075     case ARM::STC_OFFSET:
1076     case ARM::STC_PRE:
1077     case ARM::STC_POST:
1078     case ARM::STC_OPTION:
1079     case ARM::STCL_OFFSET:
1080     case ARM::STCL_PRE:
1081     case ARM::STCL_POST:
1082     case ARM::STCL_OPTION:
1083       if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1084         return MCDisassembler::Fail;
1085       break;
1086     default:
1087       break;
1088   }
1089 
1090   return S;
1091 }
1092 
1093 static DecodeStatus
1094 DecodeAddrMode2IdxInstruction(llvm::MCInst &Inst, unsigned Insn,
1095                               uint64_t Address, const void *Decoder) {
1096   DecodeStatus S = MCDisassembler::Success;
1097 
1098   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1099   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
1100   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1101   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
1102   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1103   unsigned reg = fieldFromInstruction32(Insn, 25, 1);
1104   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1105   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1106 
1107   // On stores, the writeback operand precedes Rt.
1108   switch (Inst.getOpcode()) {
1109     case ARM::STR_POST_IMM:
1110     case ARM::STR_POST_REG:
1111     case ARM::STRB_POST_IMM:
1112     case ARM::STRB_POST_REG:
1113     case ARM::STRT_POST_REG:
1114     case ARM::STRT_POST_IMM:
1115     case ARM::STRBT_POST_REG:
1116     case ARM::STRBT_POST_IMM:
1117       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1118         return MCDisassembler::Fail;
1119       break;
1120     default:
1121       break;
1122   }
1123 
1124   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
1125     return MCDisassembler::Fail;
1126 
1127   // On loads, the writeback operand comes after Rt.
1128   switch (Inst.getOpcode()) {
1129     case ARM::LDR_POST_IMM:
1130     case ARM::LDR_POST_REG:
1131     case ARM::LDRB_POST_IMM:
1132     case ARM::LDRB_POST_REG:
1133     case ARM::LDRBT_POST_REG:
1134     case ARM::LDRBT_POST_IMM:
1135     case ARM::LDRT_POST_REG:
1136     case ARM::LDRT_POST_IMM:
1137       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1138         return MCDisassembler::Fail;
1139       break;
1140     default:
1141       break;
1142   }
1143 
1144   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1145     return MCDisassembler::Fail;
1146 
1147   ARM_AM::AddrOpc Op = ARM_AM::add;
1148   if (!fieldFromInstruction32(Insn, 23, 1))
1149     Op = ARM_AM::sub;
1150 
1151   bool writeback = (P == 0) || (W == 1);
1152   unsigned idx_mode = 0;
1153   if (P && writeback)
1154     idx_mode = ARMII::IndexModePre;
1155   else if (!P && writeback)
1156     idx_mode = ARMII::IndexModePost;
1157 
1158   if (writeback && (Rn == 15 || Rn == Rt))
1159     S = MCDisassembler::SoftFail; // UNPREDICTABLE
1160 
1161   if (reg) {
1162     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1163       return MCDisassembler::Fail;
1164     ARM_AM::ShiftOpc Opc = ARM_AM::lsl;
1165     switch( fieldFromInstruction32(Insn, 5, 2)) {
1166       case 0:
1167         Opc = ARM_AM::lsl;
1168         break;
1169       case 1:
1170         Opc = ARM_AM::lsr;
1171         break;
1172       case 2:
1173         Opc = ARM_AM::asr;
1174         break;
1175       case 3:
1176         Opc = ARM_AM::ror;
1177         break;
1178       default:
1179         return MCDisassembler::Fail;
1180     }
1181     unsigned amt = fieldFromInstruction32(Insn, 7, 5);
1182     unsigned imm = ARM_AM::getAM2Opc(Op, amt, Opc, idx_mode);
1183 
1184     Inst.addOperand(MCOperand::CreateImm(imm));
1185   } else {
1186     Inst.addOperand(MCOperand::CreateReg(0));
1187     unsigned tmp = ARM_AM::getAM2Opc(Op, imm, ARM_AM::lsl, idx_mode);
1188     Inst.addOperand(MCOperand::CreateImm(tmp));
1189   }
1190 
1191   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1192     return MCDisassembler::Fail;
1193 
1194   return S;
1195 }
1196 
1197 static DecodeStatus DecodeSORegMemOperand(llvm::MCInst &Inst, unsigned Val,
1198                                   uint64_t Address, const void *Decoder) {
1199   DecodeStatus S = MCDisassembler::Success;
1200 
1201   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
1202   unsigned Rm = fieldFromInstruction32(Val,  0, 4);
1203   unsigned type = fieldFromInstruction32(Val, 5, 2);
1204   unsigned imm = fieldFromInstruction32(Val, 7, 5);
1205   unsigned U = fieldFromInstruction32(Val, 12, 1);
1206 
1207   ARM_AM::ShiftOpc ShOp = ARM_AM::lsl;
1208   switch (type) {
1209     case 0:
1210       ShOp = ARM_AM::lsl;
1211       break;
1212     case 1:
1213       ShOp = ARM_AM::lsr;
1214       break;
1215     case 2:
1216       ShOp = ARM_AM::asr;
1217       break;
1218     case 3:
1219       ShOp = ARM_AM::ror;
1220       break;
1221   }
1222 
1223   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1224     return MCDisassembler::Fail;
1225   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1226     return MCDisassembler::Fail;
1227   unsigned shift;
1228   if (U)
1229     shift = ARM_AM::getAM2Opc(ARM_AM::add, imm, ShOp);
1230   else
1231     shift = ARM_AM::getAM2Opc(ARM_AM::sub, imm, ShOp);
1232   Inst.addOperand(MCOperand::CreateImm(shift));
1233 
1234   return S;
1235 }
1236 
1237 static DecodeStatus
1238 DecodeAddrMode3Instruction(llvm::MCInst &Inst, unsigned Insn,
1239                            uint64_t Address, const void *Decoder) {
1240   DecodeStatus S = MCDisassembler::Success;
1241 
1242   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
1243   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1244   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1245   unsigned type = fieldFromInstruction32(Insn, 22, 1);
1246   unsigned imm = fieldFromInstruction32(Insn, 8, 4);
1247   unsigned U = ((~fieldFromInstruction32(Insn, 23, 1)) & 1) << 8;
1248   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1249   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1250   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1251 
1252   bool writeback = (W == 1) | (P == 0);
1253 
1254   // For {LD,ST}RD, Rt must be even, else undefined.
1255   switch (Inst.getOpcode()) {
1256     case ARM::STRD:
1257     case ARM::STRD_PRE:
1258     case ARM::STRD_POST:
1259     case ARM::LDRD:
1260     case ARM::LDRD_PRE:
1261     case ARM::LDRD_POST:
1262       if (Rt & 0x1) return MCDisassembler::Fail;
1263       break;
1264     default:
1265       break;
1266   }
1267 
1268   if (writeback) { // Writeback
1269     if (P)
1270       U |= ARMII::IndexModePre << 9;
1271     else
1272       U |= ARMII::IndexModePost << 9;
1273 
1274     // On stores, the writeback operand precedes Rt.
1275     switch (Inst.getOpcode()) {
1276     case ARM::STRD:
1277     case ARM::STRD_PRE:
1278     case ARM::STRD_POST:
1279     case ARM::STRH:
1280     case ARM::STRH_PRE:
1281     case ARM::STRH_POST:
1282       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1283         return MCDisassembler::Fail;
1284       break;
1285     default:
1286       break;
1287     }
1288   }
1289 
1290   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
1291     return MCDisassembler::Fail;
1292   switch (Inst.getOpcode()) {
1293     case ARM::STRD:
1294     case ARM::STRD_PRE:
1295     case ARM::STRD_POST:
1296     case ARM::LDRD:
1297     case ARM::LDRD_PRE:
1298     case ARM::LDRD_POST:
1299       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
1300         return MCDisassembler::Fail;
1301       break;
1302     default:
1303       break;
1304   }
1305 
1306   if (writeback) {
1307     // On loads, the writeback operand comes after Rt.
1308     switch (Inst.getOpcode()) {
1309     case ARM::LDRD:
1310     case ARM::LDRD_PRE:
1311     case ARM::LDRD_POST:
1312     case ARM::LDRH:
1313     case ARM::LDRH_PRE:
1314     case ARM::LDRH_POST:
1315     case ARM::LDRSH:
1316     case ARM::LDRSH_PRE:
1317     case ARM::LDRSH_POST:
1318     case ARM::LDRSB:
1319     case ARM::LDRSB_PRE:
1320     case ARM::LDRSB_POST:
1321     case ARM::LDRHTr:
1322     case ARM::LDRSBTr:
1323       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1324         return MCDisassembler::Fail;
1325       break;
1326     default:
1327       break;
1328     }
1329   }
1330 
1331   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1332     return MCDisassembler::Fail;
1333 
1334   if (type) {
1335     Inst.addOperand(MCOperand::CreateReg(0));
1336     Inst.addOperand(MCOperand::CreateImm(U | (imm << 4) | Rm));
1337   } else {
1338     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1339     return MCDisassembler::Fail;
1340     Inst.addOperand(MCOperand::CreateImm(U));
1341   }
1342 
1343   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1344     return MCDisassembler::Fail;
1345 
1346   return S;
1347 }
1348 
1349 static DecodeStatus DecodeRFEInstruction(llvm::MCInst &Inst, unsigned Insn,
1350                                  uint64_t Address, const void *Decoder) {
1351   DecodeStatus S = MCDisassembler::Success;
1352 
1353   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1354   unsigned mode = fieldFromInstruction32(Insn, 23, 2);
1355 
1356   switch (mode) {
1357     case 0:
1358       mode = ARM_AM::da;
1359       break;
1360     case 1:
1361       mode = ARM_AM::ia;
1362       break;
1363     case 2:
1364       mode = ARM_AM::db;
1365       break;
1366     case 3:
1367       mode = ARM_AM::ib;
1368       break;
1369   }
1370 
1371   Inst.addOperand(MCOperand::CreateImm(mode));
1372   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1373     return MCDisassembler::Fail;
1374 
1375   return S;
1376 }
1377 
1378 static DecodeStatus DecodeMemMultipleWritebackInstruction(llvm::MCInst &Inst,
1379                                   unsigned Insn,
1380                                   uint64_t Address, const void *Decoder) {
1381   DecodeStatus S = MCDisassembler::Success;
1382 
1383   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1384   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1385   unsigned reglist = fieldFromInstruction32(Insn, 0, 16);
1386 
1387   if (pred == 0xF) {
1388     switch (Inst.getOpcode()) {
1389       case ARM::LDMDA:
1390         Inst.setOpcode(ARM::RFEDA);
1391         break;
1392       case ARM::LDMDA_UPD:
1393         Inst.setOpcode(ARM::RFEDA_UPD);
1394         break;
1395       case ARM::LDMDB:
1396         Inst.setOpcode(ARM::RFEDB);
1397         break;
1398       case ARM::LDMDB_UPD:
1399         Inst.setOpcode(ARM::RFEDB_UPD);
1400         break;
1401       case ARM::LDMIA:
1402         Inst.setOpcode(ARM::RFEIA);
1403         break;
1404       case ARM::LDMIA_UPD:
1405         Inst.setOpcode(ARM::RFEIA_UPD);
1406         break;
1407       case ARM::LDMIB:
1408         Inst.setOpcode(ARM::RFEIB);
1409         break;
1410       case ARM::LDMIB_UPD:
1411         Inst.setOpcode(ARM::RFEIB_UPD);
1412         break;
1413       case ARM::STMDA:
1414         Inst.setOpcode(ARM::SRSDA);
1415         break;
1416       case ARM::STMDA_UPD:
1417         Inst.setOpcode(ARM::SRSDA_UPD);
1418         break;
1419       case ARM::STMDB:
1420         Inst.setOpcode(ARM::SRSDB);
1421         break;
1422       case ARM::STMDB_UPD:
1423         Inst.setOpcode(ARM::SRSDB_UPD);
1424         break;
1425       case ARM::STMIA:
1426         Inst.setOpcode(ARM::SRSIA);
1427         break;
1428       case ARM::STMIA_UPD:
1429         Inst.setOpcode(ARM::SRSIA_UPD);
1430         break;
1431       case ARM::STMIB:
1432         Inst.setOpcode(ARM::SRSIB);
1433         break;
1434       case ARM::STMIB_UPD:
1435         Inst.setOpcode(ARM::SRSIB_UPD);
1436         break;
1437       default:
1438         if (!Check(S, MCDisassembler::Fail)) return MCDisassembler::Fail;
1439     }
1440 
1441     // For stores (which become SRS's, the only operand is the mode.
1442     if (fieldFromInstruction32(Insn, 20, 1) == 0) {
1443       Inst.addOperand(
1444           MCOperand::CreateImm(fieldFromInstruction32(Insn, 0, 4)));
1445       return S;
1446     }
1447 
1448     return DecodeRFEInstruction(Inst, Insn, Address, Decoder);
1449   }
1450 
1451   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1452     return MCDisassembler::Fail;
1453   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1454     return MCDisassembler::Fail; // Tied
1455   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1456     return MCDisassembler::Fail;
1457   if (!Check(S, DecodeRegListOperand(Inst, reglist, Address, Decoder)))
1458     return MCDisassembler::Fail;
1459 
1460   return S;
1461 }
1462 
1463 static DecodeStatus DecodeCPSInstruction(llvm::MCInst &Inst, unsigned Insn,
1464                                  uint64_t Address, const void *Decoder) {
1465   unsigned imod = fieldFromInstruction32(Insn, 18, 2);
1466   unsigned M = fieldFromInstruction32(Insn, 17, 1);
1467   unsigned iflags = fieldFromInstruction32(Insn, 6, 3);
1468   unsigned mode = fieldFromInstruction32(Insn, 0, 5);
1469 
1470   DecodeStatus S = MCDisassembler::Success;
1471 
1472   // imod == '01' --> UNPREDICTABLE
1473   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
1474   // return failure here.  The '01' imod value is unprintable, so there's
1475   // nothing useful we could do even if we returned UNPREDICTABLE.
1476 
1477   if (imod == 1) return MCDisassembler::Fail;
1478 
1479   if (imod && M) {
1480     Inst.setOpcode(ARM::CPS3p);
1481     Inst.addOperand(MCOperand::CreateImm(imod));
1482     Inst.addOperand(MCOperand::CreateImm(iflags));
1483     Inst.addOperand(MCOperand::CreateImm(mode));
1484   } else if (imod && !M) {
1485     Inst.setOpcode(ARM::CPS2p);
1486     Inst.addOperand(MCOperand::CreateImm(imod));
1487     Inst.addOperand(MCOperand::CreateImm(iflags));
1488     if (mode) S = MCDisassembler::SoftFail;
1489   } else if (!imod && M) {
1490     Inst.setOpcode(ARM::CPS1p);
1491     Inst.addOperand(MCOperand::CreateImm(mode));
1492     if (iflags) S = MCDisassembler::SoftFail;
1493   } else {
1494     // imod == '00' && M == '0' --> UNPREDICTABLE
1495     Inst.setOpcode(ARM::CPS1p);
1496     Inst.addOperand(MCOperand::CreateImm(mode));
1497     S = MCDisassembler::SoftFail;
1498   }
1499 
1500   return S;
1501 }
1502 
1503 static DecodeStatus DecodeT2CPSInstruction(llvm::MCInst &Inst, unsigned Insn,
1504                                  uint64_t Address, const void *Decoder) {
1505   unsigned imod = fieldFromInstruction32(Insn, 9, 2);
1506   unsigned M = fieldFromInstruction32(Insn, 8, 1);
1507   unsigned iflags = fieldFromInstruction32(Insn, 5, 3);
1508   unsigned mode = fieldFromInstruction32(Insn, 0, 5);
1509 
1510   DecodeStatus S = MCDisassembler::Success;
1511 
1512   // imod == '01' --> UNPREDICTABLE
1513   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
1514   // return failure here.  The '01' imod value is unprintable, so there's
1515   // nothing useful we could do even if we returned UNPREDICTABLE.
1516 
1517   if (imod == 1) return MCDisassembler::Fail;
1518 
1519   if (imod && M) {
1520     Inst.setOpcode(ARM::t2CPS3p);
1521     Inst.addOperand(MCOperand::CreateImm(imod));
1522     Inst.addOperand(MCOperand::CreateImm(iflags));
1523     Inst.addOperand(MCOperand::CreateImm(mode));
1524   } else if (imod && !M) {
1525     Inst.setOpcode(ARM::t2CPS2p);
1526     Inst.addOperand(MCOperand::CreateImm(imod));
1527     Inst.addOperand(MCOperand::CreateImm(iflags));
1528     if (mode) S = MCDisassembler::SoftFail;
1529   } else if (!imod && M) {
1530     Inst.setOpcode(ARM::t2CPS1p);
1531     Inst.addOperand(MCOperand::CreateImm(mode));
1532     if (iflags) S = MCDisassembler::SoftFail;
1533   } else {
1534     // imod == '00' && M == '0' --> UNPREDICTABLE
1535     Inst.setOpcode(ARM::t2CPS1p);
1536     Inst.addOperand(MCOperand::CreateImm(mode));
1537     S = MCDisassembler::SoftFail;
1538   }
1539 
1540   return S;
1541 }
1542 
1543 
1544 static DecodeStatus DecodeSMLAInstruction(llvm::MCInst &Inst, unsigned Insn,
1545                                  uint64_t Address, const void *Decoder) {
1546   DecodeStatus S = MCDisassembler::Success;
1547 
1548   unsigned Rd = fieldFromInstruction32(Insn, 16, 4);
1549   unsigned Rn = fieldFromInstruction32(Insn, 0, 4);
1550   unsigned Rm = fieldFromInstruction32(Insn, 8, 4);
1551   unsigned Ra = fieldFromInstruction32(Insn, 12, 4);
1552   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1553 
1554   if (pred == 0xF)
1555     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
1556 
1557   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
1558     return MCDisassembler::Fail;
1559   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
1560     return MCDisassembler::Fail;
1561   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1562     return MCDisassembler::Fail;
1563   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Ra, Address, Decoder)))
1564     return MCDisassembler::Fail;
1565 
1566   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1567     return MCDisassembler::Fail;
1568 
1569   return S;
1570 }
1571 
1572 static DecodeStatus DecodeAddrModeImm12Operand(llvm::MCInst &Inst, unsigned Val,
1573                            uint64_t Address, const void *Decoder) {
1574   DecodeStatus S = MCDisassembler::Success;
1575 
1576   unsigned add = fieldFromInstruction32(Val, 12, 1);
1577   unsigned imm = fieldFromInstruction32(Val, 0, 12);
1578   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
1579 
1580   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1581     return MCDisassembler::Fail;
1582 
1583   if (!add) imm *= -1;
1584   if (imm == 0 && !add) imm = INT32_MIN;
1585   Inst.addOperand(MCOperand::CreateImm(imm));
1586 
1587   return S;
1588 }
1589 
1590 static DecodeStatus DecodeAddrMode5Operand(llvm::MCInst &Inst, unsigned Val,
1591                                    uint64_t Address, const void *Decoder) {
1592   DecodeStatus S = MCDisassembler::Success;
1593 
1594   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
1595   unsigned U = fieldFromInstruction32(Val, 8, 1);
1596   unsigned imm = fieldFromInstruction32(Val, 0, 8);
1597 
1598   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1599     return MCDisassembler::Fail;
1600 
1601   if (U)
1602     Inst.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(ARM_AM::add, imm)));
1603   else
1604     Inst.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(ARM_AM::sub, imm)));
1605 
1606   return S;
1607 }
1608 
1609 static DecodeStatus DecodeAddrMode7Operand(llvm::MCInst &Inst, unsigned Val,
1610                                    uint64_t Address, const void *Decoder) {
1611   return DecodeGPRRegisterClass(Inst, Val, Address, Decoder);
1612 }
1613 
1614 static DecodeStatus
1615 DecodeBranchImmInstruction(llvm::MCInst &Inst, unsigned Insn,
1616                            uint64_t Address, const void *Decoder) {
1617   DecodeStatus S = MCDisassembler::Success;
1618 
1619   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1620   unsigned imm = fieldFromInstruction32(Insn, 0, 24) << 2;
1621 
1622   if (pred == 0xF) {
1623     Inst.setOpcode(ARM::BLXi);
1624     imm |= fieldFromInstruction32(Insn, 24, 1) << 1;
1625     Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(imm)));
1626     return S;
1627   }
1628 
1629   Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(imm)));
1630   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1631     return MCDisassembler::Fail;
1632 
1633   return S;
1634 }
1635 
1636 
1637 static DecodeStatus DecodeVCVTImmOperand(llvm::MCInst &Inst, unsigned Val,
1638                                  uint64_t Address, const void *Decoder) {
1639   Inst.addOperand(MCOperand::CreateImm(64 - Val));
1640   return MCDisassembler::Success;
1641 }
1642 
1643 static DecodeStatus DecodeAddrMode6Operand(llvm::MCInst &Inst, unsigned Val,
1644                                    uint64_t Address, const void *Decoder) {
1645   DecodeStatus S = MCDisassembler::Success;
1646 
1647   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
1648   unsigned align = fieldFromInstruction32(Val, 4, 2);
1649 
1650   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1651     return MCDisassembler::Fail;
1652   if (!align)
1653     Inst.addOperand(MCOperand::CreateImm(0));
1654   else
1655     Inst.addOperand(MCOperand::CreateImm(4 << align));
1656 
1657   return S;
1658 }
1659 
1660 static DecodeStatus DecodeVLDInstruction(llvm::MCInst &Inst, unsigned Insn,
1661                                    uint64_t Address, const void *Decoder) {
1662   DecodeStatus S = MCDisassembler::Success;
1663 
1664   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
1665   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
1666   unsigned wb = fieldFromInstruction32(Insn, 16, 4);
1667   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1668   Rn |= fieldFromInstruction32(Insn, 4, 2) << 4;
1669   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1670 
1671   // First output register
1672   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
1673     return MCDisassembler::Fail;
1674 
1675   // Second output register
1676   switch (Inst.getOpcode()) {
1677     case ARM::VLD1q8:
1678     case ARM::VLD1q16:
1679     case ARM::VLD1q32:
1680     case ARM::VLD1q64:
1681     case ARM::VLD1q8_UPD:
1682     case ARM::VLD1q16_UPD:
1683     case ARM::VLD1q32_UPD:
1684     case ARM::VLD1q64_UPD:
1685     case ARM::VLD1d8T:
1686     case ARM::VLD1d16T:
1687     case ARM::VLD1d32T:
1688     case ARM::VLD1d64T:
1689     case ARM::VLD1d8T_UPD:
1690     case ARM::VLD1d16T_UPD:
1691     case ARM::VLD1d32T_UPD:
1692     case ARM::VLD1d64T_UPD:
1693     case ARM::VLD1d8Q:
1694     case ARM::VLD1d16Q:
1695     case ARM::VLD1d32Q:
1696     case ARM::VLD1d64Q:
1697     case ARM::VLD1d8Q_UPD:
1698     case ARM::VLD1d16Q_UPD:
1699     case ARM::VLD1d32Q_UPD:
1700     case ARM::VLD1d64Q_UPD:
1701     case ARM::VLD2d8:
1702     case ARM::VLD2d16:
1703     case ARM::VLD2d32:
1704     case ARM::VLD2d8_UPD:
1705     case ARM::VLD2d16_UPD:
1706     case ARM::VLD2d32_UPD:
1707     case ARM::VLD2q8:
1708     case ARM::VLD2q16:
1709     case ARM::VLD2q32:
1710     case ARM::VLD2q8_UPD:
1711     case ARM::VLD2q16_UPD:
1712     case ARM::VLD2q32_UPD:
1713     case ARM::VLD3d8:
1714     case ARM::VLD3d16:
1715     case ARM::VLD3d32:
1716     case ARM::VLD3d8_UPD:
1717     case ARM::VLD3d16_UPD:
1718     case ARM::VLD3d32_UPD:
1719     case ARM::VLD4d8:
1720     case ARM::VLD4d16:
1721     case ARM::VLD4d32:
1722     case ARM::VLD4d8_UPD:
1723     case ARM::VLD4d16_UPD:
1724     case ARM::VLD4d32_UPD:
1725       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
1726         return MCDisassembler::Fail;
1727       break;
1728     case ARM::VLD2b8:
1729     case ARM::VLD2b16:
1730     case ARM::VLD2b32:
1731     case ARM::VLD2b8_UPD:
1732     case ARM::VLD2b16_UPD:
1733     case ARM::VLD2b32_UPD:
1734     case ARM::VLD3q8:
1735     case ARM::VLD3q16:
1736     case ARM::VLD3q32:
1737     case ARM::VLD3q8_UPD:
1738     case ARM::VLD3q16_UPD:
1739     case ARM::VLD3q32_UPD:
1740     case ARM::VLD4q8:
1741     case ARM::VLD4q16:
1742     case ARM::VLD4q32:
1743     case ARM::VLD4q8_UPD:
1744     case ARM::VLD4q16_UPD:
1745     case ARM::VLD4q32_UPD:
1746       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
1747         return MCDisassembler::Fail;
1748     default:
1749       break;
1750   }
1751 
1752   // Third output register
1753   switch(Inst.getOpcode()) {
1754     case ARM::VLD1d8T:
1755     case ARM::VLD1d16T:
1756     case ARM::VLD1d32T:
1757     case ARM::VLD1d64T:
1758     case ARM::VLD1d8T_UPD:
1759     case ARM::VLD1d16T_UPD:
1760     case ARM::VLD1d32T_UPD:
1761     case ARM::VLD1d64T_UPD:
1762     case ARM::VLD1d8Q:
1763     case ARM::VLD1d16Q:
1764     case ARM::VLD1d32Q:
1765     case ARM::VLD1d64Q:
1766     case ARM::VLD1d8Q_UPD:
1767     case ARM::VLD1d16Q_UPD:
1768     case ARM::VLD1d32Q_UPD:
1769     case ARM::VLD1d64Q_UPD:
1770     case ARM::VLD2q8:
1771     case ARM::VLD2q16:
1772     case ARM::VLD2q32:
1773     case ARM::VLD2q8_UPD:
1774     case ARM::VLD2q16_UPD:
1775     case ARM::VLD2q32_UPD:
1776     case ARM::VLD3d8:
1777     case ARM::VLD3d16:
1778     case ARM::VLD3d32:
1779     case ARM::VLD3d8_UPD:
1780     case ARM::VLD3d16_UPD:
1781     case ARM::VLD3d32_UPD:
1782     case ARM::VLD4d8:
1783     case ARM::VLD4d16:
1784     case ARM::VLD4d32:
1785     case ARM::VLD4d8_UPD:
1786     case ARM::VLD4d16_UPD:
1787     case ARM::VLD4d32_UPD:
1788       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
1789         return MCDisassembler::Fail;
1790       break;
1791     case ARM::VLD3q8:
1792     case ARM::VLD3q16:
1793     case ARM::VLD3q32:
1794     case ARM::VLD3q8_UPD:
1795     case ARM::VLD3q16_UPD:
1796     case ARM::VLD3q32_UPD:
1797     case ARM::VLD4q8:
1798     case ARM::VLD4q16:
1799     case ARM::VLD4q32:
1800     case ARM::VLD4q8_UPD:
1801     case ARM::VLD4q16_UPD:
1802     case ARM::VLD4q32_UPD:
1803       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
1804         return MCDisassembler::Fail;
1805       break;
1806     default:
1807       break;
1808   }
1809 
1810   // Fourth output register
1811   switch (Inst.getOpcode()) {
1812     case ARM::VLD1d8Q:
1813     case ARM::VLD1d16Q:
1814     case ARM::VLD1d32Q:
1815     case ARM::VLD1d64Q:
1816     case ARM::VLD1d8Q_UPD:
1817     case ARM::VLD1d16Q_UPD:
1818     case ARM::VLD1d32Q_UPD:
1819     case ARM::VLD1d64Q_UPD:
1820     case ARM::VLD2q8:
1821     case ARM::VLD2q16:
1822     case ARM::VLD2q32:
1823     case ARM::VLD2q8_UPD:
1824     case ARM::VLD2q16_UPD:
1825     case ARM::VLD2q32_UPD:
1826     case ARM::VLD4d8:
1827     case ARM::VLD4d16:
1828     case ARM::VLD4d32:
1829     case ARM::VLD4d8_UPD:
1830     case ARM::VLD4d16_UPD:
1831     case ARM::VLD4d32_UPD:
1832       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
1833         return MCDisassembler::Fail;
1834       break;
1835     case ARM::VLD4q8:
1836     case ARM::VLD4q16:
1837     case ARM::VLD4q32:
1838     case ARM::VLD4q8_UPD:
1839     case ARM::VLD4q16_UPD:
1840     case ARM::VLD4q32_UPD:
1841       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
1842         return MCDisassembler::Fail;
1843       break;
1844     default:
1845       break;
1846   }
1847 
1848   // Writeback operand
1849   switch (Inst.getOpcode()) {
1850     case ARM::VLD1d8_UPD:
1851     case ARM::VLD1d16_UPD:
1852     case ARM::VLD1d32_UPD:
1853     case ARM::VLD1d64_UPD:
1854     case ARM::VLD1q8_UPD:
1855     case ARM::VLD1q16_UPD:
1856     case ARM::VLD1q32_UPD:
1857     case ARM::VLD1q64_UPD:
1858     case ARM::VLD1d8T_UPD:
1859     case ARM::VLD1d16T_UPD:
1860     case ARM::VLD1d32T_UPD:
1861     case ARM::VLD1d64T_UPD:
1862     case ARM::VLD1d8Q_UPD:
1863     case ARM::VLD1d16Q_UPD:
1864     case ARM::VLD1d32Q_UPD:
1865     case ARM::VLD1d64Q_UPD:
1866     case ARM::VLD2d8_UPD:
1867     case ARM::VLD2d16_UPD:
1868     case ARM::VLD2d32_UPD:
1869     case ARM::VLD2q8_UPD:
1870     case ARM::VLD2q16_UPD:
1871     case ARM::VLD2q32_UPD:
1872     case ARM::VLD2b8_UPD:
1873     case ARM::VLD2b16_UPD:
1874     case ARM::VLD2b32_UPD:
1875     case ARM::VLD3d8_UPD:
1876     case ARM::VLD3d16_UPD:
1877     case ARM::VLD3d32_UPD:
1878     case ARM::VLD3q8_UPD:
1879     case ARM::VLD3q16_UPD:
1880     case ARM::VLD3q32_UPD:
1881     case ARM::VLD4d8_UPD:
1882     case ARM::VLD4d16_UPD:
1883     case ARM::VLD4d32_UPD:
1884     case ARM::VLD4q8_UPD:
1885     case ARM::VLD4q16_UPD:
1886     case ARM::VLD4q32_UPD:
1887       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
1888         return MCDisassembler::Fail;
1889       break;
1890     default:
1891       break;
1892   }
1893 
1894   // AddrMode6 Base (register+alignment)
1895   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
1896     return MCDisassembler::Fail;
1897 
1898   // AddrMode6 Offset (register)
1899   if (Rm == 0xD)
1900     Inst.addOperand(MCOperand::CreateReg(0));
1901   else if (Rm != 0xF) {
1902     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1903       return MCDisassembler::Fail;
1904   }
1905 
1906   return S;
1907 }
1908 
1909 static DecodeStatus DecodeVSTInstruction(llvm::MCInst &Inst, unsigned Insn,
1910                                  uint64_t Address, const void *Decoder) {
1911   DecodeStatus S = MCDisassembler::Success;
1912 
1913   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
1914   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
1915   unsigned wb = fieldFromInstruction32(Insn, 16, 4);
1916   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1917   Rn |= fieldFromInstruction32(Insn, 4, 2) << 4;
1918   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1919 
1920   // Writeback Operand
1921   switch (Inst.getOpcode()) {
1922     case ARM::VST1d8_UPD:
1923     case ARM::VST1d16_UPD:
1924     case ARM::VST1d32_UPD:
1925     case ARM::VST1d64_UPD:
1926     case ARM::VST1q8_UPD:
1927     case ARM::VST1q16_UPD:
1928     case ARM::VST1q32_UPD:
1929     case ARM::VST1q64_UPD:
1930     case ARM::VST1d8T_UPD:
1931     case ARM::VST1d16T_UPD:
1932     case ARM::VST1d32T_UPD:
1933     case ARM::VST1d64T_UPD:
1934     case ARM::VST1d8Q_UPD:
1935     case ARM::VST1d16Q_UPD:
1936     case ARM::VST1d32Q_UPD:
1937     case ARM::VST1d64Q_UPD:
1938     case ARM::VST2d8_UPD:
1939     case ARM::VST2d16_UPD:
1940     case ARM::VST2d32_UPD:
1941     case ARM::VST2q8_UPD:
1942     case ARM::VST2q16_UPD:
1943     case ARM::VST2q32_UPD:
1944     case ARM::VST2b8_UPD:
1945     case ARM::VST2b16_UPD:
1946     case ARM::VST2b32_UPD:
1947     case ARM::VST3d8_UPD:
1948     case ARM::VST3d16_UPD:
1949     case ARM::VST3d32_UPD:
1950     case ARM::VST3q8_UPD:
1951     case ARM::VST3q16_UPD:
1952     case ARM::VST3q32_UPD:
1953     case ARM::VST4d8_UPD:
1954     case ARM::VST4d16_UPD:
1955     case ARM::VST4d32_UPD:
1956     case ARM::VST4q8_UPD:
1957     case ARM::VST4q16_UPD:
1958     case ARM::VST4q32_UPD:
1959       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
1960         return MCDisassembler::Fail;
1961       break;
1962     default:
1963       break;
1964   }
1965 
1966   // AddrMode6 Base (register+alignment)
1967   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
1968     return MCDisassembler::Fail;
1969 
1970   // AddrMode6 Offset (register)
1971   if (Rm == 0xD)
1972     Inst.addOperand(MCOperand::CreateReg(0));
1973   else if (Rm != 0xF) {
1974     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1975     return MCDisassembler::Fail;
1976   }
1977 
1978   // First input register
1979   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
1980     return MCDisassembler::Fail;
1981 
1982   // Second input register
1983   switch (Inst.getOpcode()) {
1984     case ARM::VST1q8:
1985     case ARM::VST1q16:
1986     case ARM::VST1q32:
1987     case ARM::VST1q64:
1988     case ARM::VST1q8_UPD:
1989     case ARM::VST1q16_UPD:
1990     case ARM::VST1q32_UPD:
1991     case ARM::VST1q64_UPD:
1992     case ARM::VST1d8T:
1993     case ARM::VST1d16T:
1994     case ARM::VST1d32T:
1995     case ARM::VST1d64T:
1996     case ARM::VST1d8T_UPD:
1997     case ARM::VST1d16T_UPD:
1998     case ARM::VST1d32T_UPD:
1999     case ARM::VST1d64T_UPD:
2000     case ARM::VST1d8Q:
2001     case ARM::VST1d16Q:
2002     case ARM::VST1d32Q:
2003     case ARM::VST1d64Q:
2004     case ARM::VST1d8Q_UPD:
2005     case ARM::VST1d16Q_UPD:
2006     case ARM::VST1d32Q_UPD:
2007     case ARM::VST1d64Q_UPD:
2008     case ARM::VST2d8:
2009     case ARM::VST2d16:
2010     case ARM::VST2d32:
2011     case ARM::VST2d8_UPD:
2012     case ARM::VST2d16_UPD:
2013     case ARM::VST2d32_UPD:
2014     case ARM::VST2q8:
2015     case ARM::VST2q16:
2016     case ARM::VST2q32:
2017     case ARM::VST2q8_UPD:
2018     case ARM::VST2q16_UPD:
2019     case ARM::VST2q32_UPD:
2020     case ARM::VST3d8:
2021     case ARM::VST3d16:
2022     case ARM::VST3d32:
2023     case ARM::VST3d8_UPD:
2024     case ARM::VST3d16_UPD:
2025     case ARM::VST3d32_UPD:
2026     case ARM::VST4d8:
2027     case ARM::VST4d16:
2028     case ARM::VST4d32:
2029     case ARM::VST4d8_UPD:
2030     case ARM::VST4d16_UPD:
2031     case ARM::VST4d32_UPD:
2032       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
2033         return MCDisassembler::Fail;
2034       break;
2035     case ARM::VST2b8:
2036     case ARM::VST2b16:
2037     case ARM::VST2b32:
2038     case ARM::VST2b8_UPD:
2039     case ARM::VST2b16_UPD:
2040     case ARM::VST2b32_UPD:
2041     case ARM::VST3q8:
2042     case ARM::VST3q16:
2043     case ARM::VST3q32:
2044     case ARM::VST3q8_UPD:
2045     case ARM::VST3q16_UPD:
2046     case ARM::VST3q32_UPD:
2047     case ARM::VST4q8:
2048     case ARM::VST4q16:
2049     case ARM::VST4q32:
2050     case ARM::VST4q8_UPD:
2051     case ARM::VST4q16_UPD:
2052     case ARM::VST4q32_UPD:
2053       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2054         return MCDisassembler::Fail;
2055       break;
2056     default:
2057       break;
2058   }
2059 
2060   // Third input register
2061   switch (Inst.getOpcode()) {
2062     case ARM::VST1d8T:
2063     case ARM::VST1d16T:
2064     case ARM::VST1d32T:
2065     case ARM::VST1d64T:
2066     case ARM::VST1d8T_UPD:
2067     case ARM::VST1d16T_UPD:
2068     case ARM::VST1d32T_UPD:
2069     case ARM::VST1d64T_UPD:
2070     case ARM::VST1d8Q:
2071     case ARM::VST1d16Q:
2072     case ARM::VST1d32Q:
2073     case ARM::VST1d64Q:
2074     case ARM::VST1d8Q_UPD:
2075     case ARM::VST1d16Q_UPD:
2076     case ARM::VST1d32Q_UPD:
2077     case ARM::VST1d64Q_UPD:
2078     case ARM::VST2q8:
2079     case ARM::VST2q16:
2080     case ARM::VST2q32:
2081     case ARM::VST2q8_UPD:
2082     case ARM::VST2q16_UPD:
2083     case ARM::VST2q32_UPD:
2084     case ARM::VST3d8:
2085     case ARM::VST3d16:
2086     case ARM::VST3d32:
2087     case ARM::VST3d8_UPD:
2088     case ARM::VST3d16_UPD:
2089     case ARM::VST3d32_UPD:
2090     case ARM::VST4d8:
2091     case ARM::VST4d16:
2092     case ARM::VST4d32:
2093     case ARM::VST4d8_UPD:
2094     case ARM::VST4d16_UPD:
2095     case ARM::VST4d32_UPD:
2096       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2097         return MCDisassembler::Fail;
2098       break;
2099     case ARM::VST3q8:
2100     case ARM::VST3q16:
2101     case ARM::VST3q32:
2102     case ARM::VST3q8_UPD:
2103     case ARM::VST3q16_UPD:
2104     case ARM::VST3q32_UPD:
2105     case ARM::VST4q8:
2106     case ARM::VST4q16:
2107     case ARM::VST4q32:
2108     case ARM::VST4q8_UPD:
2109     case ARM::VST4q16_UPD:
2110     case ARM::VST4q32_UPD:
2111       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
2112         return MCDisassembler::Fail;
2113       break;
2114     default:
2115       break;
2116   }
2117 
2118   // Fourth input register
2119   switch (Inst.getOpcode()) {
2120     case ARM::VST1d8Q:
2121     case ARM::VST1d16Q:
2122     case ARM::VST1d32Q:
2123     case ARM::VST1d64Q:
2124     case ARM::VST1d8Q_UPD:
2125     case ARM::VST1d16Q_UPD:
2126     case ARM::VST1d32Q_UPD:
2127     case ARM::VST1d64Q_UPD:
2128     case ARM::VST2q8:
2129     case ARM::VST2q16:
2130     case ARM::VST2q32:
2131     case ARM::VST2q8_UPD:
2132     case ARM::VST2q16_UPD:
2133     case ARM::VST2q32_UPD:
2134     case ARM::VST4d8:
2135     case ARM::VST4d16:
2136     case ARM::VST4d32:
2137     case ARM::VST4d8_UPD:
2138     case ARM::VST4d16_UPD:
2139     case ARM::VST4d32_UPD:
2140       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
2141         return MCDisassembler::Fail;
2142       break;
2143     case ARM::VST4q8:
2144     case ARM::VST4q16:
2145     case ARM::VST4q32:
2146     case ARM::VST4q8_UPD:
2147     case ARM::VST4q16_UPD:
2148     case ARM::VST4q32_UPD:
2149       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
2150         return MCDisassembler::Fail;
2151       break;
2152     default:
2153       break;
2154   }
2155 
2156   return S;
2157 }
2158 
2159 static DecodeStatus DecodeVLD1DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2160                                     uint64_t Address, const void *Decoder) {
2161   DecodeStatus S = MCDisassembler::Success;
2162 
2163   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2164   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2165   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2166   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2167   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2168   unsigned size = fieldFromInstruction32(Insn, 6, 2);
2169   unsigned regs = fieldFromInstruction32(Insn, 5, 1) + 1;
2170 
2171   align *= (1 << size);
2172 
2173   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2174     return MCDisassembler::Fail;
2175   if (regs == 2) {
2176     if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
2177       return MCDisassembler::Fail;
2178   }
2179   if (Rm != 0xF) {
2180     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2181       return MCDisassembler::Fail;
2182   }
2183 
2184   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2185     return MCDisassembler::Fail;
2186   Inst.addOperand(MCOperand::CreateImm(align));
2187 
2188   if (Rm == 0xD)
2189     Inst.addOperand(MCOperand::CreateReg(0));
2190   else if (Rm != 0xF) {
2191     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2192       return MCDisassembler::Fail;
2193   }
2194 
2195   return S;
2196 }
2197 
2198 static DecodeStatus DecodeVLD2DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2199                                     uint64_t Address, const void *Decoder) {
2200   DecodeStatus S = MCDisassembler::Success;
2201 
2202   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2203   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2204   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2205   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2206   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2207   unsigned size = 1 << fieldFromInstruction32(Insn, 6, 2);
2208   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2209   align *= 2*size;
2210 
2211   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2212     return MCDisassembler::Fail;
2213   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
2214     return MCDisassembler::Fail;
2215   if (Rm != 0xF) {
2216     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2217       return MCDisassembler::Fail;
2218   }
2219 
2220   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2221     return MCDisassembler::Fail;
2222   Inst.addOperand(MCOperand::CreateImm(align));
2223 
2224   if (Rm == 0xD)
2225     Inst.addOperand(MCOperand::CreateReg(0));
2226   else if (Rm != 0xF) {
2227     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2228       return MCDisassembler::Fail;
2229   }
2230 
2231   return S;
2232 }
2233 
2234 static DecodeStatus DecodeVLD3DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2235                                     uint64_t Address, const void *Decoder) {
2236   DecodeStatus S = MCDisassembler::Success;
2237 
2238   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2239   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2240   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2241   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2242   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2243 
2244   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2245     return MCDisassembler::Fail;
2246   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
2247     return MCDisassembler::Fail;
2248   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
2249     return MCDisassembler::Fail;
2250   if (Rm != 0xF) {
2251     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2252       return MCDisassembler::Fail;
2253   }
2254 
2255   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2256     return MCDisassembler::Fail;
2257   Inst.addOperand(MCOperand::CreateImm(0));
2258 
2259   if (Rm == 0xD)
2260     Inst.addOperand(MCOperand::CreateReg(0));
2261   else if (Rm != 0xF) {
2262     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2263       return MCDisassembler::Fail;
2264   }
2265 
2266   return S;
2267 }
2268 
2269 static DecodeStatus DecodeVLD4DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2270                                     uint64_t Address, const void *Decoder) {
2271   DecodeStatus S = MCDisassembler::Success;
2272 
2273   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2274   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2275   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2276   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2277   unsigned size = fieldFromInstruction32(Insn, 6, 2);
2278   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2279   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2280 
2281   if (size == 0x3) {
2282     size = 4;
2283     align = 16;
2284   } else {
2285     if (size == 2) {
2286       size = 1 << size;
2287       align *= 8;
2288     } else {
2289       size = 1 << size;
2290       align *= 4*size;
2291     }
2292   }
2293 
2294   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2295     return MCDisassembler::Fail;
2296   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
2297     return MCDisassembler::Fail;
2298   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
2299     return MCDisassembler::Fail;
2300   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3*inc)%32, Address, Decoder)))
2301     return MCDisassembler::Fail;
2302   if (Rm != 0xF) {
2303     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2304       return MCDisassembler::Fail;
2305   }
2306 
2307   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2308     return MCDisassembler::Fail;
2309   Inst.addOperand(MCOperand::CreateImm(align));
2310 
2311   if (Rm == 0xD)
2312     Inst.addOperand(MCOperand::CreateReg(0));
2313   else if (Rm != 0xF) {
2314     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2315       return MCDisassembler::Fail;
2316   }
2317 
2318   return S;
2319 }
2320 
2321 static DecodeStatus
2322 DecodeNEONModImmInstruction(llvm::MCInst &Inst, unsigned Insn,
2323                             uint64_t Address, const void *Decoder) {
2324   DecodeStatus S = MCDisassembler::Success;
2325 
2326   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2327   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2328   unsigned imm = fieldFromInstruction32(Insn, 0, 4);
2329   imm |= fieldFromInstruction32(Insn, 16, 3) << 4;
2330   imm |= fieldFromInstruction32(Insn, 24, 1) << 7;
2331   imm |= fieldFromInstruction32(Insn, 8, 4) << 8;
2332   imm |= fieldFromInstruction32(Insn, 5, 1) << 12;
2333   unsigned Q = fieldFromInstruction32(Insn, 6, 1);
2334 
2335   if (Q) {
2336     if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2337     return MCDisassembler::Fail;
2338   } else {
2339     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2340     return MCDisassembler::Fail;
2341   }
2342 
2343   Inst.addOperand(MCOperand::CreateImm(imm));
2344 
2345   switch (Inst.getOpcode()) {
2346     case ARM::VORRiv4i16:
2347     case ARM::VORRiv2i32:
2348     case ARM::VBICiv4i16:
2349     case ARM::VBICiv2i32:
2350       if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2351         return MCDisassembler::Fail;
2352       break;
2353     case ARM::VORRiv8i16:
2354     case ARM::VORRiv4i32:
2355     case ARM::VBICiv8i16:
2356     case ARM::VBICiv4i32:
2357       if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2358         return MCDisassembler::Fail;
2359       break;
2360     default:
2361       break;
2362   }
2363 
2364   return S;
2365 }
2366 
2367 static DecodeStatus DecodeVSHLMaxInstruction(llvm::MCInst &Inst, unsigned Insn,
2368                                         uint64_t Address, const void *Decoder) {
2369   DecodeStatus S = MCDisassembler::Success;
2370 
2371   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2372   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2373   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2374   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
2375   unsigned size = fieldFromInstruction32(Insn, 18, 2);
2376 
2377   if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
2378     return MCDisassembler::Fail;
2379   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
2380     return MCDisassembler::Fail;
2381   Inst.addOperand(MCOperand::CreateImm(8 << size));
2382 
2383   return S;
2384 }
2385 
2386 static DecodeStatus DecodeShiftRight8Imm(llvm::MCInst &Inst, unsigned Val,
2387                                uint64_t Address, const void *Decoder) {
2388   Inst.addOperand(MCOperand::CreateImm(8 - Val));
2389   return MCDisassembler::Success;
2390 }
2391 
2392 static DecodeStatus DecodeShiftRight16Imm(llvm::MCInst &Inst, unsigned Val,
2393                                uint64_t Address, const void *Decoder) {
2394   Inst.addOperand(MCOperand::CreateImm(16 - Val));
2395   return MCDisassembler::Success;
2396 }
2397 
2398 static DecodeStatus DecodeShiftRight32Imm(llvm::MCInst &Inst, unsigned Val,
2399                                uint64_t Address, const void *Decoder) {
2400   Inst.addOperand(MCOperand::CreateImm(32 - Val));
2401   return MCDisassembler::Success;
2402 }
2403 
2404 static DecodeStatus DecodeShiftRight64Imm(llvm::MCInst &Inst, unsigned Val,
2405                                uint64_t Address, const void *Decoder) {
2406   Inst.addOperand(MCOperand::CreateImm(64 - Val));
2407   return MCDisassembler::Success;
2408 }
2409 
2410 static DecodeStatus DecodeTBLInstruction(llvm::MCInst &Inst, unsigned Insn,
2411                                uint64_t Address, const void *Decoder) {
2412   DecodeStatus S = MCDisassembler::Success;
2413 
2414   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2415   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2416   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2417   Rn |= fieldFromInstruction32(Insn, 7, 1) << 4;
2418   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2419   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
2420   unsigned op = fieldFromInstruction32(Insn, 6, 1);
2421   unsigned length = fieldFromInstruction32(Insn, 8, 2) + 1;
2422 
2423   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2424     return MCDisassembler::Fail;
2425   if (op) {
2426     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2427     return MCDisassembler::Fail; // Writeback
2428   }
2429 
2430   for (unsigned i = 0; i < length; ++i) {
2431     if (!Check(S, DecodeDPRRegisterClass(Inst, (Rn+i)%32, Address, Decoder)))
2432     return MCDisassembler::Fail;
2433   }
2434 
2435   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
2436     return MCDisassembler::Fail;
2437 
2438   return S;
2439 }
2440 
2441 static DecodeStatus DecodeVFPfpImm(llvm::MCInst &Inst, unsigned Val,
2442                             uint64_t Address, const void *Decoder) {
2443   // The immediate needs to be a fully instantiated float.  However, the
2444   // auto-generated decoder is only able to fill in some of the bits
2445   // necessary.  For instance, the 'b' bit is replicated multiple times,
2446   // and is even present in inverted form in one bit.  We do a little
2447   // binary parsing here to fill in those missing bits, and then
2448   // reinterpret it all as a float.
2449   union {
2450     uint32_t integer;
2451     float fp;
2452   } fp_conv;
2453 
2454   fp_conv.integer = Val;
2455   uint32_t b = fieldFromInstruction32(Val, 25, 1);
2456   fp_conv.integer |= b << 26;
2457   fp_conv.integer |= b << 27;
2458   fp_conv.integer |= b << 28;
2459   fp_conv.integer |= b << 29;
2460   fp_conv.integer |= (~b & 0x1) << 30;
2461 
2462   Inst.addOperand(MCOperand::CreateFPImm(fp_conv.fp));
2463   return MCDisassembler::Success;
2464 }
2465 
2466 static DecodeStatus DecodeThumbAddSpecialReg(llvm::MCInst &Inst, uint16_t Insn,
2467                                      uint64_t Address, const void *Decoder) {
2468   DecodeStatus S = MCDisassembler::Success;
2469 
2470   unsigned dst = fieldFromInstruction16(Insn, 8, 3);
2471   unsigned imm = fieldFromInstruction16(Insn, 0, 8);
2472 
2473   if (!Check(S, DecodetGPRRegisterClass(Inst, dst, Address, Decoder)))
2474     return MCDisassembler::Fail;
2475 
2476   switch(Inst.getOpcode()) {
2477     default:
2478       return MCDisassembler::Fail;
2479     case ARM::tADR:
2480       break; // tADR does not explicitly represent the PC as an operand.
2481     case ARM::tADDrSPi:
2482       Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2483       break;
2484   }
2485 
2486   Inst.addOperand(MCOperand::CreateImm(imm));
2487   return S;
2488 }
2489 
2490 static DecodeStatus DecodeThumbBROperand(llvm::MCInst &Inst, unsigned Val,
2491                                  uint64_t Address, const void *Decoder) {
2492   Inst.addOperand(MCOperand::CreateImm(SignExtend32<12>(Val << 1)));
2493   return MCDisassembler::Success;
2494 }
2495 
2496 static DecodeStatus DecodeT2BROperand(llvm::MCInst &Inst, unsigned Val,
2497                                  uint64_t Address, const void *Decoder) {
2498   Inst.addOperand(MCOperand::CreateImm(SignExtend32<21>(Val)));
2499   return MCDisassembler::Success;
2500 }
2501 
2502 static DecodeStatus DecodeThumbCmpBROperand(llvm::MCInst &Inst, unsigned Val,
2503                                  uint64_t Address, const void *Decoder) {
2504   Inst.addOperand(MCOperand::CreateImm(SignExtend32<7>(Val << 1)));
2505   return MCDisassembler::Success;
2506 }
2507 
2508 static DecodeStatus DecodeThumbAddrModeRR(llvm::MCInst &Inst, unsigned Val,
2509                                  uint64_t Address, const void *Decoder) {
2510   DecodeStatus S = MCDisassembler::Success;
2511 
2512   unsigned Rn = fieldFromInstruction32(Val, 0, 3);
2513   unsigned Rm = fieldFromInstruction32(Val, 3, 3);
2514 
2515   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
2516     return MCDisassembler::Fail;
2517   if (!Check(S, DecodetGPRRegisterClass(Inst, Rm, Address, Decoder)))
2518     return MCDisassembler::Fail;
2519 
2520   return S;
2521 }
2522 
2523 static DecodeStatus DecodeThumbAddrModeIS(llvm::MCInst &Inst, unsigned Val,
2524                                   uint64_t Address, const void *Decoder) {
2525   DecodeStatus S = MCDisassembler::Success;
2526 
2527   unsigned Rn = fieldFromInstruction32(Val, 0, 3);
2528   unsigned imm = fieldFromInstruction32(Val, 3, 5);
2529 
2530   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
2531     return MCDisassembler::Fail;
2532   Inst.addOperand(MCOperand::CreateImm(imm));
2533 
2534   return S;
2535 }
2536 
2537 static DecodeStatus DecodeThumbAddrModePC(llvm::MCInst &Inst, unsigned Val,
2538                                   uint64_t Address, const void *Decoder) {
2539   Inst.addOperand(MCOperand::CreateImm(Val << 2));
2540 
2541   return MCDisassembler::Success;
2542 }
2543 
2544 static DecodeStatus DecodeThumbAddrModeSP(llvm::MCInst &Inst, unsigned Val,
2545                                   uint64_t Address, const void *Decoder) {
2546   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2547   Inst.addOperand(MCOperand::CreateImm(Val));
2548 
2549   return MCDisassembler::Success;
2550 }
2551 
2552 static DecodeStatus DecodeT2AddrModeSOReg(llvm::MCInst &Inst, unsigned Val,
2553                                   uint64_t Address, const void *Decoder) {
2554   DecodeStatus S = MCDisassembler::Success;
2555 
2556   unsigned Rn = fieldFromInstruction32(Val, 6, 4);
2557   unsigned Rm = fieldFromInstruction32(Val, 2, 4);
2558   unsigned imm = fieldFromInstruction32(Val, 0, 2);
2559 
2560   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2561     return MCDisassembler::Fail;
2562   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
2563     return MCDisassembler::Fail;
2564   Inst.addOperand(MCOperand::CreateImm(imm));
2565 
2566   return S;
2567 }
2568 
2569 static DecodeStatus DecodeT2LoadShift(llvm::MCInst &Inst, unsigned Insn,
2570                               uint64_t Address, const void *Decoder) {
2571   DecodeStatus S = MCDisassembler::Success;
2572 
2573   switch (Inst.getOpcode()) {
2574     case ARM::t2PLDs:
2575     case ARM::t2PLDWs:
2576     case ARM::t2PLIs:
2577       break;
2578     default: {
2579       unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2580       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
2581     return MCDisassembler::Fail;
2582     }
2583   }
2584 
2585   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2586   if (Rn == 0xF) {
2587     switch (Inst.getOpcode()) {
2588       case ARM::t2LDRBs:
2589         Inst.setOpcode(ARM::t2LDRBpci);
2590         break;
2591       case ARM::t2LDRHs:
2592         Inst.setOpcode(ARM::t2LDRHpci);
2593         break;
2594       case ARM::t2LDRSHs:
2595         Inst.setOpcode(ARM::t2LDRSHpci);
2596         break;
2597       case ARM::t2LDRSBs:
2598         Inst.setOpcode(ARM::t2LDRSBpci);
2599         break;
2600       case ARM::t2PLDs:
2601         Inst.setOpcode(ARM::t2PLDi12);
2602         Inst.addOperand(MCOperand::CreateReg(ARM::PC));
2603         break;
2604       default:
2605         return MCDisassembler::Fail;
2606     }
2607 
2608     int imm = fieldFromInstruction32(Insn, 0, 12);
2609     if (!fieldFromInstruction32(Insn, 23, 1)) imm *= -1;
2610     Inst.addOperand(MCOperand::CreateImm(imm));
2611 
2612     return S;
2613   }
2614 
2615   unsigned addrmode = fieldFromInstruction32(Insn, 4, 2);
2616   addrmode |= fieldFromInstruction32(Insn, 0, 4) << 2;
2617   addrmode |= fieldFromInstruction32(Insn, 16, 4) << 6;
2618   if (!Check(S, DecodeT2AddrModeSOReg(Inst, addrmode, Address, Decoder)))
2619     return MCDisassembler::Fail;
2620 
2621   return S;
2622 }
2623 
2624 static DecodeStatus DecodeT2Imm8S4(llvm::MCInst &Inst, unsigned Val,
2625                            uint64_t Address, const void *Decoder) {
2626   int imm = Val & 0xFF;
2627   if (!(Val & 0x100)) imm *= -1;
2628   Inst.addOperand(MCOperand::CreateImm(imm << 2));
2629 
2630   return MCDisassembler::Success;
2631 }
2632 
2633 static DecodeStatus DecodeT2AddrModeImm8s4(llvm::MCInst &Inst, unsigned Val,
2634                                    uint64_t Address, const void *Decoder) {
2635   DecodeStatus S = MCDisassembler::Success;
2636 
2637   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
2638   unsigned imm = fieldFromInstruction32(Val, 0, 9);
2639 
2640   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2641     return MCDisassembler::Fail;
2642   if (!Check(S, DecodeT2Imm8S4(Inst, imm, Address, Decoder)))
2643     return MCDisassembler::Fail;
2644 
2645   return S;
2646 }
2647 
2648 static DecodeStatus DecodeT2Imm8(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));
2653 
2654   return MCDisassembler::Success;
2655 }
2656 
2657 
2658 static DecodeStatus DecodeT2AddrModeImm8(llvm::MCInst &Inst, unsigned Val,
2659                                  uint64_t Address, const void *Decoder) {
2660   DecodeStatus S = MCDisassembler::Success;
2661 
2662   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
2663   unsigned imm = fieldFromInstruction32(Val, 0, 9);
2664 
2665   // Some instructions always use an additive offset.
2666   switch (Inst.getOpcode()) {
2667     case ARM::t2LDRT:
2668     case ARM::t2LDRBT:
2669     case ARM::t2LDRHT:
2670     case ARM::t2LDRSBT:
2671     case ARM::t2LDRSHT:
2672       imm |= 0x100;
2673       break;
2674     default:
2675       break;
2676   }
2677 
2678   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2679     return MCDisassembler::Fail;
2680   if (!Check(S, DecodeT2Imm8(Inst, imm, Address, Decoder)))
2681     return MCDisassembler::Fail;
2682 
2683   return S;
2684 }
2685 
2686 
2687 static DecodeStatus DecodeT2AddrModeImm12(llvm::MCInst &Inst, unsigned Val,
2688                                   uint64_t Address, const void *Decoder) {
2689   DecodeStatus S = MCDisassembler::Success;
2690 
2691   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
2692   unsigned imm = fieldFromInstruction32(Val, 0, 12);
2693 
2694   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2695     return MCDisassembler::Fail;
2696   Inst.addOperand(MCOperand::CreateImm(imm));
2697 
2698   return S;
2699 }
2700 
2701 
2702 static DecodeStatus DecodeThumbAddSPImm(llvm::MCInst &Inst, uint16_t Insn,
2703                                 uint64_t Address, const void *Decoder) {
2704   unsigned imm = fieldFromInstruction16(Insn, 0, 7);
2705 
2706   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2707   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2708   Inst.addOperand(MCOperand::CreateImm(imm));
2709 
2710   return MCDisassembler::Success;
2711 }
2712 
2713 static DecodeStatus DecodeThumbAddSPReg(llvm::MCInst &Inst, uint16_t Insn,
2714                                 uint64_t Address, const void *Decoder) {
2715   DecodeStatus S = MCDisassembler::Success;
2716 
2717   if (Inst.getOpcode() == ARM::tADDrSP) {
2718     unsigned Rdm = fieldFromInstruction16(Insn, 0, 3);
2719     Rdm |= fieldFromInstruction16(Insn, 7, 1) << 3;
2720 
2721     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
2722     return MCDisassembler::Fail;
2723     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
2724     return MCDisassembler::Fail;
2725     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2726   } else if (Inst.getOpcode() == ARM::tADDspr) {
2727     unsigned Rm = fieldFromInstruction16(Insn, 3, 4);
2728 
2729     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2730     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2731     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2732     return MCDisassembler::Fail;
2733   }
2734 
2735   return S;
2736 }
2737 
2738 static DecodeStatus DecodeThumbCPS(llvm::MCInst &Inst, uint16_t Insn,
2739                            uint64_t Address, const void *Decoder) {
2740   unsigned imod = fieldFromInstruction16(Insn, 4, 1) | 0x2;
2741   unsigned flags = fieldFromInstruction16(Insn, 0, 3);
2742 
2743   Inst.addOperand(MCOperand::CreateImm(imod));
2744   Inst.addOperand(MCOperand::CreateImm(flags));
2745 
2746   return MCDisassembler::Success;
2747 }
2748 
2749 static DecodeStatus DecodePostIdxReg(llvm::MCInst &Inst, unsigned Insn,
2750                              uint64_t Address, const void *Decoder) {
2751   DecodeStatus S = MCDisassembler::Success;
2752   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2753   unsigned add = fieldFromInstruction32(Insn, 4, 1);
2754 
2755   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2756     return MCDisassembler::Fail;
2757   Inst.addOperand(MCOperand::CreateImm(add));
2758 
2759   return S;
2760 }
2761 
2762 static DecodeStatus DecodeThumbBLXOffset(llvm::MCInst &Inst, unsigned Val,
2763                                  uint64_t Address, const void *Decoder) {
2764   Inst.addOperand(MCOperand::CreateImm(SignExtend32<22>(Val << 1)));
2765   return MCDisassembler::Success;
2766 }
2767 
2768 static DecodeStatus DecodeCoprocessor(llvm::MCInst &Inst, unsigned Val,
2769                               uint64_t Address, const void *Decoder) {
2770   if (Val == 0xA || Val == 0xB)
2771     return MCDisassembler::Fail;
2772 
2773   Inst.addOperand(MCOperand::CreateImm(Val));
2774   return MCDisassembler::Success;
2775 }
2776 
2777 static DecodeStatus
2778 DecodeThumb2BCCInstruction(llvm::MCInst &Inst, unsigned Insn,
2779                            uint64_t Address, const void *Decoder) {
2780   DecodeStatus S = MCDisassembler::Success;
2781 
2782   unsigned pred = fieldFromInstruction32(Insn, 22, 4);
2783   if (pred == 0xE || pred == 0xF) {
2784     unsigned opc = fieldFromInstruction32(Insn, 4, 28);
2785     switch (opc) {
2786       default:
2787         return MCDisassembler::Fail;
2788       case 0xf3bf8f4:
2789         Inst.setOpcode(ARM::t2DSB);
2790         break;
2791       case 0xf3bf8f5:
2792         Inst.setOpcode(ARM::t2DMB);
2793         break;
2794       case 0xf3bf8f6:
2795         Inst.setOpcode(ARM::t2ISB);
2796         break;
2797     }
2798 
2799     unsigned imm = fieldFromInstruction32(Insn, 0, 4);
2800     return DecodeMemBarrierOption(Inst, imm, Address, Decoder);
2801   }
2802 
2803   unsigned brtarget = fieldFromInstruction32(Insn, 0, 11) << 1;
2804   brtarget |= fieldFromInstruction32(Insn, 11, 1) << 19;
2805   brtarget |= fieldFromInstruction32(Insn, 13, 1) << 18;
2806   brtarget |= fieldFromInstruction32(Insn, 16, 6) << 12;
2807   brtarget |= fieldFromInstruction32(Insn, 26, 1) << 20;
2808 
2809   if (!Check(S, DecodeT2BROperand(Inst, brtarget, Address, Decoder)))
2810     return MCDisassembler::Fail;
2811   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2812     return MCDisassembler::Fail;
2813 
2814   return S;
2815 }
2816 
2817 // Decode a shifted immediate operand.  These basically consist
2818 // of an 8-bit value, and a 4-bit directive that specifies either
2819 // a splat operation or a rotation.
2820 static DecodeStatus DecodeT2SOImm(llvm::MCInst &Inst, unsigned Val,
2821                           uint64_t Address, const void *Decoder) {
2822   unsigned ctrl = fieldFromInstruction32(Val, 10, 2);
2823   if (ctrl == 0) {
2824     unsigned byte = fieldFromInstruction32(Val, 8, 2);
2825     unsigned imm = fieldFromInstruction32(Val, 0, 8);
2826     switch (byte) {
2827       case 0:
2828         Inst.addOperand(MCOperand::CreateImm(imm));
2829         break;
2830       case 1:
2831         Inst.addOperand(MCOperand::CreateImm((imm << 16) | imm));
2832         break;
2833       case 2:
2834         Inst.addOperand(MCOperand::CreateImm((imm << 24) | (imm << 8)));
2835         break;
2836       case 3:
2837         Inst.addOperand(MCOperand::CreateImm((imm << 24) | (imm << 16) |
2838                                              (imm << 8)  |  imm));
2839         break;
2840     }
2841   } else {
2842     unsigned unrot = fieldFromInstruction32(Val, 0, 7) | 0x80;
2843     unsigned rot = fieldFromInstruction32(Val, 7, 5);
2844     unsigned imm = (unrot >> rot) | (unrot << ((32-rot)&31));
2845     Inst.addOperand(MCOperand::CreateImm(imm));
2846   }
2847 
2848   return MCDisassembler::Success;
2849 }
2850 
2851 static DecodeStatus
2852 DecodeThumbBCCTargetOperand(llvm::MCInst &Inst, unsigned Val,
2853                             uint64_t Address, const void *Decoder){
2854   Inst.addOperand(MCOperand::CreateImm(Val << 1));
2855   return MCDisassembler::Success;
2856 }
2857 
2858 static DecodeStatus DecodeThumbBLTargetOperand(llvm::MCInst &Inst, unsigned Val,
2859                                        uint64_t Address, const void *Decoder){
2860   Inst.addOperand(MCOperand::CreateImm(SignExtend32<22>(Val << 1)));
2861   return MCDisassembler::Success;
2862 }
2863 
2864 static DecodeStatus DecodeMemBarrierOption(llvm::MCInst &Inst, unsigned Val,
2865                                    uint64_t Address, const void *Decoder) {
2866   switch (Val) {
2867   default:
2868     return MCDisassembler::Fail;
2869   case 0xF: // SY
2870   case 0xE: // ST
2871   case 0xB: // ISH
2872   case 0xA: // ISHST
2873   case 0x7: // NSH
2874   case 0x6: // NSHST
2875   case 0x3: // OSH
2876   case 0x2: // OSHST
2877     break;
2878   }
2879 
2880   Inst.addOperand(MCOperand::CreateImm(Val));
2881   return MCDisassembler::Success;
2882 }
2883 
2884 static DecodeStatus DecodeMSRMask(llvm::MCInst &Inst, unsigned Val,
2885                           uint64_t Address, const void *Decoder) {
2886   if (!Val) return MCDisassembler::Fail;
2887   Inst.addOperand(MCOperand::CreateImm(Val));
2888   return MCDisassembler::Success;
2889 }
2890 
2891 static DecodeStatus DecodeDoubleRegLoad(llvm::MCInst &Inst, unsigned Insn,
2892                                         uint64_t Address, const void *Decoder) {
2893   DecodeStatus S = MCDisassembler::Success;
2894 
2895   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2896   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2897   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
2898 
2899   if ((Rt & 1) || Rt == 0xE || Rn == 0xF) return MCDisassembler::Fail;
2900 
2901   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
2902     return MCDisassembler::Fail;
2903   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
2904     return MCDisassembler::Fail;
2905   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2906     return MCDisassembler::Fail;
2907   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2908     return MCDisassembler::Fail;
2909 
2910   return S;
2911 }
2912 
2913 
2914 static DecodeStatus DecodeDoubleRegStore(llvm::MCInst &Inst, unsigned Insn,
2915                                          uint64_t Address, const void *Decoder){
2916   DecodeStatus S = MCDisassembler::Success;
2917 
2918   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2919   unsigned Rt = fieldFromInstruction32(Insn, 0, 4);
2920   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2921   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
2922 
2923   if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
2924     return MCDisassembler::Fail;
2925 
2926   if ((Rt & 1) || Rt == 0xE || Rn == 0xF) return MCDisassembler::Fail;
2927   if (Rd == Rn || Rd == Rt || Rd == Rt+1) return MCDisassembler::Fail;
2928 
2929   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
2930     return MCDisassembler::Fail;
2931   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
2932     return MCDisassembler::Fail;
2933   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2934     return MCDisassembler::Fail;
2935   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2936     return MCDisassembler::Fail;
2937 
2938   return S;
2939 }
2940 
2941 static DecodeStatus DecodeLDRPreImm(llvm::MCInst &Inst, unsigned Insn,
2942                             uint64_t Address, const void *Decoder) {
2943   DecodeStatus S = MCDisassembler::Success;
2944 
2945   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2946   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2947   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
2948   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
2949   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
2950   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
2951 
2952   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
2953 
2954   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
2955     return MCDisassembler::Fail;
2956   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2957     return MCDisassembler::Fail;
2958   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
2959     return MCDisassembler::Fail;
2960   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2961     return MCDisassembler::Fail;
2962 
2963   return S;
2964 }
2965 
2966 static DecodeStatus DecodeLDRPreReg(llvm::MCInst &Inst, unsigned Insn,
2967                             uint64_t Address, const void *Decoder) {
2968   DecodeStatus S = MCDisassembler::Success;
2969 
2970   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2971   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2972   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
2973   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
2974   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
2975   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
2976   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2977 
2978   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
2979   if (Rm == 0xF) S = MCDisassembler::SoftFail;
2980 
2981   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
2982     return MCDisassembler::Fail;
2983   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2984     return MCDisassembler::Fail;
2985   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
2986     return MCDisassembler::Fail;
2987   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2988     return MCDisassembler::Fail;
2989 
2990   return S;
2991 }
2992 
2993 
2994 static DecodeStatus DecodeSTRPreImm(llvm::MCInst &Inst, unsigned Insn,
2995                             uint64_t Address, const void *Decoder) {
2996   DecodeStatus S = MCDisassembler::Success;
2997 
2998   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2999   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3000   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3001   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3002   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3003   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3004 
3005   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3006 
3007   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3008     return MCDisassembler::Fail;
3009   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3010     return MCDisassembler::Fail;
3011   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
3012     return MCDisassembler::Fail;
3013   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3014     return MCDisassembler::Fail;
3015 
3016   return S;
3017 }
3018 
3019 static DecodeStatus DecodeSTRPreReg(llvm::MCInst &Inst, unsigned Insn,
3020                             uint64_t Address, const void *Decoder) {
3021   DecodeStatus S = MCDisassembler::Success;
3022 
3023   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3024   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
3025   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
3026   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
3027   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
3028   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3029 
3030   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
3031 
3032   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3033     return MCDisassembler::Fail;
3034   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3035     return MCDisassembler::Fail;
3036   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
3037     return MCDisassembler::Fail;
3038   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3039     return MCDisassembler::Fail;
3040 
3041   return S;
3042 }
3043 
3044 static DecodeStatus DecodeVLD1LN(llvm::MCInst &Inst, unsigned Insn,
3045                          uint64_t Address, const void *Decoder) {
3046   DecodeStatus S = MCDisassembler::Success;
3047 
3048   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3049   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3050   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3051   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3052   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3053 
3054   unsigned align = 0;
3055   unsigned index = 0;
3056   switch (size) {
3057     default:
3058       return MCDisassembler::Fail;
3059     case 0:
3060       if (fieldFromInstruction32(Insn, 4, 1))
3061         return MCDisassembler::Fail; // UNDEFINED
3062       index = fieldFromInstruction32(Insn, 5, 3);
3063       break;
3064     case 1:
3065       if (fieldFromInstruction32(Insn, 5, 1))
3066         return MCDisassembler::Fail; // UNDEFINED
3067       index = fieldFromInstruction32(Insn, 6, 2);
3068       if (fieldFromInstruction32(Insn, 4, 1))
3069         align = 2;
3070       break;
3071     case 2:
3072       if (fieldFromInstruction32(Insn, 6, 1))
3073         return MCDisassembler::Fail; // UNDEFINED
3074       index = fieldFromInstruction32(Insn, 7, 1);
3075       if (fieldFromInstruction32(Insn, 4, 2) != 0)
3076         align = 4;
3077   }
3078 
3079   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3080     return MCDisassembler::Fail;
3081   if (Rm != 0xF) { // Writeback
3082     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3083       return MCDisassembler::Fail;
3084   }
3085   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3086     return MCDisassembler::Fail;
3087   Inst.addOperand(MCOperand::CreateImm(align));
3088   if (Rm != 0xF) {
3089     if (Rm != 0xD) {
3090       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3091         return MCDisassembler::Fail;
3092     } else
3093       Inst.addOperand(MCOperand::CreateReg(0));
3094   }
3095 
3096   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3097     return MCDisassembler::Fail;
3098   Inst.addOperand(MCOperand::CreateImm(index));
3099 
3100   return S;
3101 }
3102 
3103 static DecodeStatus DecodeVST1LN(llvm::MCInst &Inst, unsigned Insn,
3104                          uint64_t Address, const void *Decoder) {
3105   DecodeStatus S = MCDisassembler::Success;
3106 
3107   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3108   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3109   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3110   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3111   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3112 
3113   unsigned align = 0;
3114   unsigned index = 0;
3115   switch (size) {
3116     default:
3117       return MCDisassembler::Fail;
3118     case 0:
3119       if (fieldFromInstruction32(Insn, 4, 1))
3120         return MCDisassembler::Fail; // UNDEFINED
3121       index = fieldFromInstruction32(Insn, 5, 3);
3122       break;
3123     case 1:
3124       if (fieldFromInstruction32(Insn, 5, 1))
3125         return MCDisassembler::Fail; // UNDEFINED
3126       index = fieldFromInstruction32(Insn, 6, 2);
3127       if (fieldFromInstruction32(Insn, 4, 1))
3128         align = 2;
3129       break;
3130     case 2:
3131       if (fieldFromInstruction32(Insn, 6, 1))
3132         return MCDisassembler::Fail; // UNDEFINED
3133       index = fieldFromInstruction32(Insn, 7, 1);
3134       if (fieldFromInstruction32(Insn, 4, 2) != 0)
3135         align = 4;
3136   }
3137 
3138   if (Rm != 0xF) { // Writeback
3139     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3140     return MCDisassembler::Fail;
3141   }
3142   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3143     return MCDisassembler::Fail;
3144   Inst.addOperand(MCOperand::CreateImm(align));
3145   if (Rm != 0xF) {
3146     if (Rm != 0xD) {
3147       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3148     return MCDisassembler::Fail;
3149     } else
3150       Inst.addOperand(MCOperand::CreateReg(0));
3151   }
3152 
3153   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3154     return MCDisassembler::Fail;
3155   Inst.addOperand(MCOperand::CreateImm(index));
3156 
3157   return S;
3158 }
3159 
3160 
3161 static DecodeStatus DecodeVLD2LN(llvm::MCInst &Inst, unsigned Insn,
3162                          uint64_t Address, const void *Decoder) {
3163   DecodeStatus S = MCDisassembler::Success;
3164 
3165   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3166   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3167   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3168   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3169   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3170 
3171   unsigned align = 0;
3172   unsigned index = 0;
3173   unsigned inc = 1;
3174   switch (size) {
3175     default:
3176       return MCDisassembler::Fail;
3177     case 0:
3178       index = fieldFromInstruction32(Insn, 5, 3);
3179       if (fieldFromInstruction32(Insn, 4, 1))
3180         align = 2;
3181       break;
3182     case 1:
3183       index = fieldFromInstruction32(Insn, 6, 2);
3184       if (fieldFromInstruction32(Insn, 4, 1))
3185         align = 4;
3186       if (fieldFromInstruction32(Insn, 5, 1))
3187         inc = 2;
3188       break;
3189     case 2:
3190       if (fieldFromInstruction32(Insn, 5, 1))
3191         return MCDisassembler::Fail; // UNDEFINED
3192       index = fieldFromInstruction32(Insn, 7, 1);
3193       if (fieldFromInstruction32(Insn, 4, 1) != 0)
3194         align = 8;
3195       if (fieldFromInstruction32(Insn, 6, 1))
3196         inc = 2;
3197       break;
3198   }
3199 
3200   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3201     return MCDisassembler::Fail;
3202   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3203     return MCDisassembler::Fail;
3204   if (Rm != 0xF) { // Writeback
3205     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3206       return MCDisassembler::Fail;
3207   }
3208   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3209     return MCDisassembler::Fail;
3210   Inst.addOperand(MCOperand::CreateImm(align));
3211   if (Rm != 0xF) {
3212     if (Rm != 0xD) {
3213       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3214         return MCDisassembler::Fail;
3215     } else
3216       Inst.addOperand(MCOperand::CreateReg(0));
3217   }
3218 
3219   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3220     return MCDisassembler::Fail;
3221   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3222     return MCDisassembler::Fail;
3223   Inst.addOperand(MCOperand::CreateImm(index));
3224 
3225   return S;
3226 }
3227 
3228 static DecodeStatus DecodeVST2LN(llvm::MCInst &Inst, unsigned Insn,
3229                          uint64_t Address, const void *Decoder) {
3230   DecodeStatus S = MCDisassembler::Success;
3231 
3232   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3233   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3234   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3235   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3236   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3237 
3238   unsigned align = 0;
3239   unsigned index = 0;
3240   unsigned inc = 1;
3241   switch (size) {
3242     default:
3243       return MCDisassembler::Fail;
3244     case 0:
3245       index = fieldFromInstruction32(Insn, 5, 3);
3246       if (fieldFromInstruction32(Insn, 4, 1))
3247         align = 2;
3248       break;
3249     case 1:
3250       index = fieldFromInstruction32(Insn, 6, 2);
3251       if (fieldFromInstruction32(Insn, 4, 1))
3252         align = 4;
3253       if (fieldFromInstruction32(Insn, 5, 1))
3254         inc = 2;
3255       break;
3256     case 2:
3257       if (fieldFromInstruction32(Insn, 5, 1))
3258         return MCDisassembler::Fail; // UNDEFINED
3259       index = fieldFromInstruction32(Insn, 7, 1);
3260       if (fieldFromInstruction32(Insn, 4, 1) != 0)
3261         align = 8;
3262       if (fieldFromInstruction32(Insn, 6, 1))
3263         inc = 2;
3264       break;
3265   }
3266 
3267   if (Rm != 0xF) { // Writeback
3268     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3269       return MCDisassembler::Fail;
3270   }
3271   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3272     return MCDisassembler::Fail;
3273   Inst.addOperand(MCOperand::CreateImm(align));
3274   if (Rm != 0xF) {
3275     if (Rm != 0xD) {
3276       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3277         return MCDisassembler::Fail;
3278     } else
3279       Inst.addOperand(MCOperand::CreateReg(0));
3280   }
3281 
3282   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3283     return MCDisassembler::Fail;
3284   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3285     return MCDisassembler::Fail;
3286   Inst.addOperand(MCOperand::CreateImm(index));
3287 
3288   return S;
3289 }
3290 
3291 
3292 static DecodeStatus DecodeVLD3LN(llvm::MCInst &Inst, unsigned Insn,
3293                          uint64_t Address, const void *Decoder) {
3294   DecodeStatus S = MCDisassembler::Success;
3295 
3296   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3297   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3298   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3299   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3300   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3301 
3302   unsigned align = 0;
3303   unsigned index = 0;
3304   unsigned inc = 1;
3305   switch (size) {
3306     default:
3307       return MCDisassembler::Fail;
3308     case 0:
3309       if (fieldFromInstruction32(Insn, 4, 1))
3310         return MCDisassembler::Fail; // UNDEFINED
3311       index = fieldFromInstruction32(Insn, 5, 3);
3312       break;
3313     case 1:
3314       if (fieldFromInstruction32(Insn, 4, 1))
3315         return MCDisassembler::Fail; // UNDEFINED
3316       index = fieldFromInstruction32(Insn, 6, 2);
3317       if (fieldFromInstruction32(Insn, 5, 1))
3318         inc = 2;
3319       break;
3320     case 2:
3321       if (fieldFromInstruction32(Insn, 4, 2))
3322         return MCDisassembler::Fail; // UNDEFINED
3323       index = fieldFromInstruction32(Insn, 7, 1);
3324       if (fieldFromInstruction32(Insn, 6, 1))
3325         inc = 2;
3326       break;
3327   }
3328 
3329   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3330     return MCDisassembler::Fail;
3331   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3332     return MCDisassembler::Fail;
3333   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3334     return MCDisassembler::Fail;
3335 
3336   if (Rm != 0xF) { // Writeback
3337     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3338     return MCDisassembler::Fail;
3339   }
3340   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3341     return MCDisassembler::Fail;
3342   Inst.addOperand(MCOperand::CreateImm(align));
3343   if (Rm != 0xF) {
3344     if (Rm != 0xD) {
3345       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3346     return MCDisassembler::Fail;
3347     } else
3348       Inst.addOperand(MCOperand::CreateReg(0));
3349   }
3350 
3351   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3352     return MCDisassembler::Fail;
3353   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3354     return MCDisassembler::Fail;
3355   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3356     return MCDisassembler::Fail;
3357   Inst.addOperand(MCOperand::CreateImm(index));
3358 
3359   return S;
3360 }
3361 
3362 static DecodeStatus DecodeVST3LN(llvm::MCInst &Inst, unsigned Insn,
3363                          uint64_t Address, const void *Decoder) {
3364   DecodeStatus S = MCDisassembler::Success;
3365 
3366   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3367   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3368   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3369   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3370   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3371 
3372   unsigned align = 0;
3373   unsigned index = 0;
3374   unsigned inc = 1;
3375   switch (size) {
3376     default:
3377       return MCDisassembler::Fail;
3378     case 0:
3379       if (fieldFromInstruction32(Insn, 4, 1))
3380         return MCDisassembler::Fail; // UNDEFINED
3381       index = fieldFromInstruction32(Insn, 5, 3);
3382       break;
3383     case 1:
3384       if (fieldFromInstruction32(Insn, 4, 1))
3385         return MCDisassembler::Fail; // UNDEFINED
3386       index = fieldFromInstruction32(Insn, 6, 2);
3387       if (fieldFromInstruction32(Insn, 5, 1))
3388         inc = 2;
3389       break;
3390     case 2:
3391       if (fieldFromInstruction32(Insn, 4, 2))
3392         return MCDisassembler::Fail; // UNDEFINED
3393       index = fieldFromInstruction32(Insn, 7, 1);
3394       if (fieldFromInstruction32(Insn, 6, 1))
3395         inc = 2;
3396       break;
3397   }
3398 
3399   if (Rm != 0xF) { // Writeback
3400     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3401     return MCDisassembler::Fail;
3402   }
3403   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3404     return MCDisassembler::Fail;
3405   Inst.addOperand(MCOperand::CreateImm(align));
3406   if (Rm != 0xF) {
3407     if (Rm != 0xD) {
3408       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3409     return MCDisassembler::Fail;
3410     } else
3411       Inst.addOperand(MCOperand::CreateReg(0));
3412   }
3413 
3414   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3415     return MCDisassembler::Fail;
3416   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3417     return MCDisassembler::Fail;
3418   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3419     return MCDisassembler::Fail;
3420   Inst.addOperand(MCOperand::CreateImm(index));
3421 
3422   return S;
3423 }
3424 
3425 
3426 static DecodeStatus DecodeVLD4LN(llvm::MCInst &Inst, unsigned Insn,
3427                          uint64_t Address, const void *Decoder) {
3428   DecodeStatus S = MCDisassembler::Success;
3429 
3430   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3431   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3432   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3433   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3434   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3435 
3436   unsigned align = 0;
3437   unsigned index = 0;
3438   unsigned inc = 1;
3439   switch (size) {
3440     default:
3441       return MCDisassembler::Fail;
3442     case 0:
3443       if (fieldFromInstruction32(Insn, 4, 1))
3444         align = 4;
3445       index = fieldFromInstruction32(Insn, 5, 3);
3446       break;
3447     case 1:
3448       if (fieldFromInstruction32(Insn, 4, 1))
3449         align = 8;
3450       index = fieldFromInstruction32(Insn, 6, 2);
3451       if (fieldFromInstruction32(Insn, 5, 1))
3452         inc = 2;
3453       break;
3454     case 2:
3455       if (fieldFromInstruction32(Insn, 4, 2))
3456         align = 4 << fieldFromInstruction32(Insn, 4, 2);
3457       index = fieldFromInstruction32(Insn, 7, 1);
3458       if (fieldFromInstruction32(Insn, 6, 1))
3459         inc = 2;
3460       break;
3461   }
3462 
3463   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3464     return MCDisassembler::Fail;
3465   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3466     return MCDisassembler::Fail;
3467   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3468     return MCDisassembler::Fail;
3469   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
3470     return MCDisassembler::Fail;
3471 
3472   if (Rm != 0xF) { // Writeback
3473     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3474       return MCDisassembler::Fail;
3475   }
3476   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3477     return MCDisassembler::Fail;
3478   Inst.addOperand(MCOperand::CreateImm(align));
3479   if (Rm != 0xF) {
3480     if (Rm != 0xD) {
3481       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3482         return MCDisassembler::Fail;
3483     } else
3484       Inst.addOperand(MCOperand::CreateReg(0));
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   Inst.addOperand(MCOperand::CreateImm(index));
3496 
3497   return S;
3498 }
3499 
3500 static DecodeStatus DecodeVST4LN(llvm::MCInst &Inst, unsigned Insn,
3501                          uint64_t Address, const void *Decoder) {
3502   DecodeStatus S = MCDisassembler::Success;
3503 
3504   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3505   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3506   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3507   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3508   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3509 
3510   unsigned align = 0;
3511   unsigned index = 0;
3512   unsigned inc = 1;
3513   switch (size) {
3514     default:
3515       return MCDisassembler::Fail;
3516     case 0:
3517       if (fieldFromInstruction32(Insn, 4, 1))
3518         align = 4;
3519       index = fieldFromInstruction32(Insn, 5, 3);
3520       break;
3521     case 1:
3522       if (fieldFromInstruction32(Insn, 4, 1))
3523         align = 8;
3524       index = fieldFromInstruction32(Insn, 6, 2);
3525       if (fieldFromInstruction32(Insn, 5, 1))
3526         inc = 2;
3527       break;
3528     case 2:
3529       if (fieldFromInstruction32(Insn, 4, 2))
3530         align = 4 << fieldFromInstruction32(Insn, 4, 2);
3531       index = fieldFromInstruction32(Insn, 7, 1);
3532       if (fieldFromInstruction32(Insn, 6, 1))
3533         inc = 2;
3534       break;
3535   }
3536 
3537   if (Rm != 0xF) { // Writeback
3538     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3539     return MCDisassembler::Fail;
3540   }
3541   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3542     return MCDisassembler::Fail;
3543   Inst.addOperand(MCOperand::CreateImm(align));
3544   if (Rm != 0xF) {
3545     if (Rm != 0xD) {
3546       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3547     return MCDisassembler::Fail;
3548     } else
3549       Inst.addOperand(MCOperand::CreateReg(0));
3550   }
3551 
3552   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3553     return MCDisassembler::Fail;
3554   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
3555     return MCDisassembler::Fail;
3556   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
3557     return MCDisassembler::Fail;
3558   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
3559     return MCDisassembler::Fail;
3560   Inst.addOperand(MCOperand::CreateImm(index));
3561 
3562   return S;
3563 }
3564 
3565 static DecodeStatus DecodeVMOVSRR(llvm::MCInst &Inst, unsigned Insn,
3566                                   uint64_t Address, const void *Decoder) {
3567   DecodeStatus S = MCDisassembler::Success;
3568   unsigned Rt  = fieldFromInstruction32(Insn, 12, 4);
3569   unsigned Rt2 = fieldFromInstruction32(Insn, 16, 4);
3570   unsigned Rm  = fieldFromInstruction32(Insn,  0, 4);
3571   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3572   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
3573 
3574   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
3575     S = MCDisassembler::SoftFail;
3576 
3577   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
3578     return MCDisassembler::Fail;
3579   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
3580     return MCDisassembler::Fail;
3581   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
3582     return MCDisassembler::Fail;
3583   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
3584     return MCDisassembler::Fail;
3585   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3586     return MCDisassembler::Fail;
3587 
3588   return S;
3589 }
3590 
3591 static DecodeStatus DecodeVMOVRRS(llvm::MCInst &Inst, unsigned Insn,
3592                                   uint64_t Address, const void *Decoder) {
3593   DecodeStatus S = MCDisassembler::Success;
3594   unsigned Rt  = fieldFromInstruction32(Insn, 12, 4);
3595   unsigned Rt2 = fieldFromInstruction32(Insn, 16, 4);
3596   unsigned Rm  = fieldFromInstruction32(Insn,  0, 4);
3597   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3598   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
3599 
3600   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
3601     S = MCDisassembler::SoftFail;
3602 
3603   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
3604     return MCDisassembler::Fail;
3605   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
3606     return MCDisassembler::Fail;
3607   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
3608     return MCDisassembler::Fail;
3609   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
3610     return MCDisassembler::Fail;
3611   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
3612     return MCDisassembler::Fail;
3613 
3614   return S;
3615 }
3616 
3617 static DecodeStatus DecodeIT(llvm::MCInst &Inst, unsigned Insn,
3618                              uint64_t Address, const void *Decoder) {
3619   DecodeStatus S = MCDisassembler::Success;
3620   unsigned pred = fieldFromInstruction16(Insn, 4, 4);
3621   // The InstPrinter needs to have the low bit of the predicate in
3622   // the mask operand to be able to print it properly.
3623   unsigned mask = fieldFromInstruction16(Insn, 0, 5);
3624 
3625   if (pred == 0xF) {
3626     pred = 0xE;
3627     S = MCDisassembler::SoftFail;
3628   }
3629 
3630   if ((mask & 0xF) == 0) {
3631     // Preserve the high bit of the mask, which is the low bit of
3632     // the predicate.
3633     mask &= 0x10;
3634     mask |= 0x8;
3635     S = MCDisassembler::SoftFail;
3636   }
3637 
3638   Inst.addOperand(MCOperand::CreateImm(pred));
3639   Inst.addOperand(MCOperand::CreateImm(mask));
3640   return S;
3641 }
3642