xref: /llvm-project/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp (revision df698b032c9a9797e92b0ab3d4aebe6cf7112b2c)
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 "ARMDisassembler.h"
13 #include "ARM.h"
14 #include "ARMRegisterInfo.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/Target/TargetRegistry.h"
22 #include "llvm/Support/Debug.h"
23 #include "llvm/Support/MemoryObject.h"
24 #include "llvm/Support/ErrorHandling.h"
25 #include "llvm/Support/raw_ostream.h"
26 
27 // Pull DecodeStatus and its enum values into the global namespace.
28 typedef llvm::MCDisassembler::DecodeStatus DecodeStatus;
29 #define Success llvm::MCDisassembler::Success
30 #define Unpredictable llvm::MCDisassembler::SoftFail
31 #define Fail llvm::MCDisassembler::Fail
32 
33 // Helper macro to perform setwise reduction of the current running status
34 // and another status, and return if the new status is Fail.
35 #define CHECK(S,X) do {                           \
36     S = (DecodeStatus) ((int)S & (X));            \
37     if (S == Fail) return Fail;                   \
38   } while(0)
39 
40 // Forward declare these because the autogenerated code will reference them.
41 // Definitions are further down.
42 static DecodeStatus DecodeGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
43                                    uint64_t Address, const void *Decoder);
44 static DecodeStatus DecodeGPRnopcRegisterClass(llvm::MCInst &Inst,
45                                                unsigned RegNo, uint64_t Address,
46                                                const void *Decoder);
47 static DecodeStatus DecodetGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
48                                    uint64_t Address, const void *Decoder);
49 static DecodeStatus DecodetcGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
50                                    uint64_t Address, const void *Decoder);
51 static DecodeStatus DecoderGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
52                                    uint64_t Address, const void *Decoder);
53 static DecodeStatus DecodeSPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
54                                    uint64_t Address, const void *Decoder);
55 static DecodeStatus DecodeDPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
56                                    uint64_t Address, const void *Decoder);
57 static DecodeStatus DecodeDPR_8RegisterClass(llvm::MCInst &Inst, unsigned RegNo,
58                                    uint64_t Address, const void *Decoder);
59 static DecodeStatus DecodeDPR_VFP2RegisterClass(llvm::MCInst &Inst,
60                                                 unsigned RegNo,
61                                                 uint64_t Address,
62                                                 const void *Decoder);
63 static DecodeStatus DecodeQPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
64                                    uint64_t Address, const void *Decoder);
65 
66 static DecodeStatus DecodePredicateOperand(llvm::MCInst &Inst, unsigned Val,
67                                uint64_t Address, const void *Decoder);
68 static DecodeStatus DecodeCCOutOperand(llvm::MCInst &Inst, unsigned Val,
69                                uint64_t Address, const void *Decoder);
70 static DecodeStatus DecodeSOImmOperand(llvm::MCInst &Inst, unsigned Val,
71                                uint64_t Address, const void *Decoder);
72 static DecodeStatus DecodeBLTargetOperand(llvm::MCInst &Inst, unsigned Val,
73                                uint64_t Address, const void *Decoder);
74 static DecodeStatus DecodeRegListOperand(llvm::MCInst &Inst, unsigned Val,
75                                uint64_t Address, const void *Decoder);
76 static DecodeStatus DecodeSPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
77                                uint64_t Address, const void *Decoder);
78 static DecodeStatus DecodeDPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
79                                uint64_t Address, const void *Decoder);
80 
81 static DecodeStatus DecodeBitfieldMaskOperand(llvm::MCInst &Inst, unsigned Insn,
82                                uint64_t Address, const void *Decoder);
83 static DecodeStatus DecodeCopMemInstruction(llvm::MCInst &Inst, unsigned Insn,
84                                uint64_t Address, const void *Decoder);
85 static DecodeStatus DecodeAddrMode2IdxInstruction(llvm::MCInst &Inst,
86                                                   unsigned Insn,
87                                                   uint64_t Address,
88                                                   const void *Decoder);
89 static DecodeStatus DecodeSORegMemOperand(llvm::MCInst &Inst, unsigned Insn,
90                                uint64_t Address, const void *Decoder);
91 static DecodeStatus DecodeAddrMode3Instruction(llvm::MCInst &Inst,unsigned Insn,
92                                uint64_t Address, const void *Decoder);
93 static DecodeStatus DecodeSORegImmOperand(llvm::MCInst &Inst, unsigned Insn,
94                                uint64_t Address, const void *Decoder);
95 static DecodeStatus DecodeSORegRegOperand(llvm::MCInst &Inst, unsigned Insn,
96                                uint64_t Address, const void *Decoder);
97 
98 static DecodeStatus DecodeMemMultipleWritebackInstruction(llvm::MCInst & Inst,
99                                                   unsigned Insn,
100                                                   uint64_t Adddress,
101                                                   const void *Decoder);
102 static DecodeStatus DecodeSMLAInstruction(llvm::MCInst &Inst, unsigned Insn,
103                                uint64_t Address, const void *Decoder);
104 static DecodeStatus DecodeCPSInstruction(llvm::MCInst &Inst, unsigned Insn,
105                                uint64_t Address, const void *Decoder);
106 static DecodeStatus DecodeAddrModeImm12Operand(llvm::MCInst &Inst, unsigned Val,
107                                uint64_t Address, const void *Decoder);
108 static DecodeStatus DecodeAddrMode5Operand(llvm::MCInst &Inst, unsigned Val,
109                                uint64_t Address, const void *Decoder);
110 static DecodeStatus DecodeAddrMode7Operand(llvm::MCInst &Inst, unsigned Val,
111                                uint64_t Address, const void *Decoder);
112 static DecodeStatus DecodeBranchImmInstruction(llvm::MCInst &Inst,unsigned Insn,
113                                uint64_t Address, const void *Decoder);
114 static DecodeStatus DecodeVCVTImmOperand(llvm::MCInst &Inst, unsigned Val,
115                                uint64_t Address, const void *Decoder);
116 static DecodeStatus DecodeAddrMode6Operand(llvm::MCInst &Inst, unsigned Val,
117                                uint64_t Address, const void *Decoder);
118 static DecodeStatus DecodeVLDInstruction(llvm::MCInst &Inst, unsigned Val,
119                                uint64_t Address, const void *Decoder);
120 static DecodeStatus DecodeVSTInstruction(llvm::MCInst &Inst, unsigned Val,
121                                uint64_t Address, const void *Decoder);
122 static DecodeStatus DecodeVLD1DupInstruction(llvm::MCInst &Inst, unsigned Val,
123                                uint64_t Address, const void *Decoder);
124 static DecodeStatus DecodeVLD2DupInstruction(llvm::MCInst &Inst, unsigned Val,
125                                uint64_t Address, const void *Decoder);
126 static DecodeStatus DecodeVLD3DupInstruction(llvm::MCInst &Inst, unsigned Val,
127                                uint64_t Address, const void *Decoder);
128 static DecodeStatus DecodeVLD4DupInstruction(llvm::MCInst &Inst, unsigned Val,
129                                uint64_t Address, const void *Decoder);
130 static DecodeStatus DecodeNEONModImmInstruction(llvm::MCInst &Inst,unsigned Val,
131                                uint64_t Address, const void *Decoder);
132 static DecodeStatus DecodeVSHLMaxInstruction(llvm::MCInst &Inst, unsigned Val,
133                                uint64_t Address, const void *Decoder);
134 static DecodeStatus DecodeShiftRight8Imm(llvm::MCInst &Inst, unsigned Val,
135                                uint64_t Address, const void *Decoder);
136 static DecodeStatus DecodeShiftRight16Imm(llvm::MCInst &Inst, unsigned Val,
137                                uint64_t Address, const void *Decoder);
138 static DecodeStatus DecodeShiftRight32Imm(llvm::MCInst &Inst, unsigned Val,
139                                uint64_t Address, const void *Decoder);
140 static DecodeStatus DecodeShiftRight64Imm(llvm::MCInst &Inst, unsigned Val,
141                                uint64_t Address, const void *Decoder);
142 static DecodeStatus DecodeTBLInstruction(llvm::MCInst &Inst, unsigned Insn,
143                                uint64_t Address, const void *Decoder);
144 static DecodeStatus DecodeVFPfpImm(llvm::MCInst &Inst, unsigned Val,
145                                uint64_t Address, const void *Decoder);
146 static DecodeStatus DecodePostIdxReg(llvm::MCInst &Inst, unsigned Insn,
147                                uint64_t Address, const void *Decoder);
148 static DecodeStatus DecodeCoprocessor(llvm::MCInst &Inst, unsigned Insn,
149                                uint64_t Address, const void *Decoder);
150 static DecodeStatus DecodeMemBarrierOption(llvm::MCInst &Inst, unsigned Insn,
151                                uint64_t Address, const void *Decoder);
152 static DecodeStatus DecodeMSRMask(llvm::MCInst &Inst, unsigned Insn,
153                                uint64_t Address, const void *Decoder);
154 static DecodeStatus DecodeDoubleRegLoad(llvm::MCInst &Inst, unsigned Insn,
155                                uint64_t Address, const void *Decoder);
156 static DecodeStatus DecodeDoubleRegStore(llvm::MCInst &Inst, unsigned Insn,
157                                uint64_t Address, const void *Decoder);
158 static DecodeStatus DecodeSTRPreImm(llvm::MCInst &Inst, unsigned Insn,
159                                uint64_t Address, const void *Decoder);
160 static DecodeStatus DecodeSTRPreReg(llvm::MCInst &Inst, unsigned Insn,
161                                uint64_t Address, const void *Decoder);
162 static DecodeStatus DecodeVLD1LN(llvm::MCInst &Inst, unsigned Insn,
163                                uint64_t Address, const void *Decoder);
164 static DecodeStatus DecodeVLD2LN(llvm::MCInst &Inst, unsigned Insn,
165                                uint64_t Address, const void *Decoder);
166 static DecodeStatus DecodeVLD3LN(llvm::MCInst &Inst, unsigned Insn,
167                                uint64_t Address, const void *Decoder);
168 static DecodeStatus DecodeVLD4LN(llvm::MCInst &Inst, unsigned Insn,
169                                uint64_t Address, const void *Decoder);
170 static DecodeStatus DecodeVST1LN(llvm::MCInst &Inst, unsigned Insn,
171                                uint64_t Address, const void *Decoder);
172 static DecodeStatus DecodeVST2LN(llvm::MCInst &Inst, unsigned Insn,
173                                uint64_t Address, const void *Decoder);
174 static DecodeStatus DecodeVST3LN(llvm::MCInst &Inst, unsigned Insn,
175                                uint64_t Address, const void *Decoder);
176 static DecodeStatus DecodeVST4LN(llvm::MCInst &Inst, unsigned Insn,
177                                uint64_t Address, const void *Decoder);
178 static DecodeStatus DecodeVMOVSRR(llvm::MCInst &Inst, unsigned Insn,
179                                uint64_t Address, const void *Decoder);
180 static DecodeStatus DecodeVMOVRRS(llvm::MCInst &Inst, unsigned Insn,
181                                uint64_t Address, const void *Decoder);
182 
183 
184 static DecodeStatus DecodeThumbAddSpecialReg(llvm::MCInst &Inst, uint16_t Insn,
185                                uint64_t Address, const void *Decoder);
186 static DecodeStatus DecodeThumbBROperand(llvm::MCInst &Inst, unsigned Val,
187                                uint64_t Address, const void *Decoder);
188 static DecodeStatus DecodeT2BROperand(llvm::MCInst &Inst, unsigned Val,
189                                uint64_t Address, const void *Decoder);
190 static DecodeStatus DecodeThumbCmpBROperand(llvm::MCInst &Inst, unsigned Val,
191                                uint64_t Address, const void *Decoder);
192 static DecodeStatus DecodeThumbAddrModeRR(llvm::MCInst &Inst, unsigned Val,
193                                uint64_t Address, const void *Decoder);
194 static DecodeStatus DecodeThumbAddrModeIS(llvm::MCInst &Inst, unsigned Val,
195                                uint64_t Address, const void *Decoder);
196 static DecodeStatus DecodeThumbAddrModePC(llvm::MCInst &Inst, unsigned Val,
197                                uint64_t Address, const void *Decoder);
198 static DecodeStatus DecodeThumbAddrModeSP(llvm::MCInst &Inst, unsigned Val,
199                                uint64_t Address, const void *Decoder);
200 static DecodeStatus DecodeT2AddrModeSOReg(llvm::MCInst &Inst, unsigned Val,
201                                uint64_t Address, const void *Decoder);
202 static DecodeStatus DecodeT2LoadShift(llvm::MCInst &Inst, unsigned Val,
203                                uint64_t Address, const void *Decoder);
204 static DecodeStatus DecodeT2Imm8S4(llvm::MCInst &Inst, unsigned Val,
205                                uint64_t Address, const void *Decoder);
206 static DecodeStatus DecodeT2AddrModeImm8s4(llvm::MCInst &Inst, unsigned Val,
207                                uint64_t Address, const void *Decoder);
208 static DecodeStatus DecodeT2Imm8(llvm::MCInst &Inst, unsigned Val,
209                                uint64_t Address, const void *Decoder);
210 static DecodeStatus DecodeT2AddrModeImm8(llvm::MCInst &Inst, unsigned Val,
211                                uint64_t Address, const void *Decoder);
212 static DecodeStatus DecodeThumbAddSPImm(llvm::MCInst &Inst, uint16_t Val,
213                                uint64_t Address, const void *Decoder);
214 static DecodeStatus DecodeThumbAddSPReg(llvm::MCInst &Inst, uint16_t Insn,
215                                 uint64_t Address, const void *Decoder);
216 static DecodeStatus DecodeThumbCPS(llvm::MCInst &Inst, uint16_t Insn,
217                                 uint64_t Address, const void *Decoder);
218 static DecodeStatus DecodeThumbBLXOffset(llvm::MCInst &Inst, unsigned Insn,
219                                 uint64_t Address, const void *Decoder);
220 static DecodeStatus DecodeT2AddrModeImm12(llvm::MCInst &Inst, unsigned Val,
221                                 uint64_t Address, const void *Decoder);
222 static DecodeStatus DecodeThumb2BCCInstruction(llvm::MCInst &Inst, unsigned Val,
223                                 uint64_t Address, const void *Decoder);
224 static DecodeStatus DecodeT2SOImm(llvm::MCInst &Inst, unsigned Val,
225                                 uint64_t Address, const void *Decoder);
226 static DecodeStatus DecodeThumbBCCTargetOperand(llvm::MCInst &Inst,unsigned Val,
227                                 uint64_t Address, const void *Decoder);
228 static DecodeStatus DecodeThumbBLTargetOperand(llvm::MCInst &Inst, unsigned Val,
229                                 uint64_t Address, const void *Decoder);
230 
231 #include "ARMGenDisassemblerTables.inc"
232 #include "ARMGenInstrInfo.inc"
233 #include "ARMGenEDInfo.inc"
234 
235 using namespace llvm;
236 
237 static MCDisassembler *createARMDisassembler(const Target &T) {
238   return new ARMDisassembler;
239 }
240 
241 static MCDisassembler *createThumbDisassembler(const Target &T) {
242   return new ThumbDisassembler;
243 }
244 
245 EDInstInfo *ARMDisassembler::getEDInfo() const {
246   return instInfoARM;
247 }
248 
249 EDInstInfo *ThumbDisassembler::getEDInfo() const {
250   return instInfoARM;
251 }
252 
253 DecodeStatus ARMDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
254                                              const MemoryObject &Region,
255                                              uint64_t Address,
256                                              raw_ostream &os) const {
257   uint8_t bytes[4];
258 
259   // We want to read exactly 4 bytes of data.
260   if (Region.readBytes(Address, 4, (uint8_t*)bytes, NULL) == -1)
261     return Fail;
262 
263   // Encoded as a small-endian 32-bit word in the stream.
264   uint32_t insn = (bytes[3] << 24) |
265                   (bytes[2] << 16) |
266                   (bytes[1] <<  8) |
267                   (bytes[0] <<  0);
268 
269   // Calling the auto-generated decoder function.
270   DecodeStatus result = decodeARMInstruction32(MI, insn, Address, this);
271   if (result != Fail) {
272     Size = 4;
273     return result;
274   }
275 
276   // Instructions that are shared between ARM and Thumb modes.
277   // FIXME: This shouldn't really exist.  It's an artifact of the
278   // fact that we fail to encode a few instructions properly for Thumb.
279   MI.clear();
280   result = decodeCommonInstruction32(MI, insn, Address, this);
281   if (result != Fail) {
282     Size = 4;
283     return result;
284   }
285 
286   // VFP and NEON instructions, similarly, are shared between ARM
287   // and Thumb modes.
288   MI.clear();
289   result = decodeVFPInstruction32(MI, insn, Address, this);
290   if (result != Fail) {
291     Size = 4;
292     return result;
293   }
294 
295   MI.clear();
296   result = decodeNEONDataInstruction32(MI, insn, Address, this);
297   if (result != Fail) {
298     Size = 4;
299     // Add a fake predicate operand, because we share these instruction
300     // definitions with Thumb2 where these instructions are predicable.
301     if (!DecodePredicateOperand(MI, 0xE, Address, this)) return Fail;
302     return result;
303   }
304 
305   MI.clear();
306   result = decodeNEONLoadStoreInstruction32(MI, insn, Address, this);
307   if (result != Fail) {
308     Size = 4;
309     // Add a fake predicate operand, because we share these instruction
310     // definitions with Thumb2 where these instructions are predicable.
311     if (!DecodePredicateOperand(MI, 0xE, Address, this)) return Fail;
312     return result;
313   }
314 
315   MI.clear();
316   result = decodeNEONDupInstruction32(MI, insn, Address, this);
317   if (result != Fail) {
318     Size = 4;
319     // Add a fake predicate operand, because we share these instruction
320     // definitions with Thumb2 where these instructions are predicable.
321     if (!DecodePredicateOperand(MI, 0xE, Address, this)) return Fail;
322     return result;
323   }
324 
325   MI.clear();
326 
327   return Fail;
328 }
329 
330 namespace llvm {
331 extern MCInstrDesc ARMInsts[];
332 }
333 
334 // Thumb1 instructions don't have explicit S bits.  Rather, they
335 // implicitly set CPSR.  Since it's not represented in the encoding, the
336 // auto-generated decoder won't inject the CPSR operand.  We need to fix
337 // that as a post-pass.
338 static void AddThumb1SBit(MCInst &MI, bool InITBlock) {
339   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
340   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
341   MCInst::iterator I = MI.begin();
342   for (unsigned i = 0; i < NumOps; ++i, ++I) {
343     if (I == MI.end()) break;
344     if (OpInfo[i].isOptionalDef() && OpInfo[i].RegClass == ARM::CCRRegClassID) {
345       if (i > 0 && OpInfo[i-1].isPredicate()) continue;
346       MI.insert(I, MCOperand::CreateReg(InITBlock ? 0 : ARM::CPSR));
347       return;
348     }
349   }
350 
351   MI.insert(I, MCOperand::CreateReg(InITBlock ? 0 : ARM::CPSR));
352 }
353 
354 // Most Thumb instructions don't have explicit predicates in the
355 // encoding, but rather get their predicates from IT context.  We need
356 // to fix up the predicate operands using this context information as a
357 // post-pass.
358 void ThumbDisassembler::AddThumbPredicate(MCInst &MI) const {
359   // A few instructions actually have predicates encoded in them.  Don't
360   // try to overwrite it if we're seeing one of those.
361   switch (MI.getOpcode()) {
362     case ARM::tBcc:
363     case ARM::t2Bcc:
364       return;
365     default:
366       break;
367   }
368 
369   // If we're in an IT block, base the predicate on that.  Otherwise,
370   // assume a predicate of AL.
371   unsigned CC;
372   if (!ITBlock.empty()) {
373     CC = ITBlock.back();
374     ITBlock.pop_back();
375   } else
376     CC = ARMCC::AL;
377 
378   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
379   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
380   MCInst::iterator I = MI.begin();
381   for (unsigned i = 0; i < NumOps; ++i, ++I) {
382     if (I == MI.end()) break;
383     if (OpInfo[i].isPredicate()) {
384       I = MI.insert(I, MCOperand::CreateImm(CC));
385       ++I;
386       if (CC == ARMCC::AL)
387         MI.insert(I, MCOperand::CreateReg(0));
388       else
389         MI.insert(I, MCOperand::CreateReg(ARM::CPSR));
390       return;
391     }
392   }
393 
394   I = MI.insert(I, MCOperand::CreateImm(CC));
395   ++I;
396   if (CC == ARMCC::AL)
397     MI.insert(I, MCOperand::CreateReg(0));
398   else
399     MI.insert(I, MCOperand::CreateReg(ARM::CPSR));
400 }
401 
402 // Thumb VFP instructions are a special case.  Because we share their
403 // encodings between ARM and Thumb modes, and they are predicable in ARM
404 // mode, the auto-generated decoder will give them an (incorrect)
405 // predicate operand.  We need to rewrite these operands based on the IT
406 // context as a post-pass.
407 void ThumbDisassembler::UpdateThumbVFPPredicate(MCInst &MI) const {
408   unsigned CC;
409   if (!ITBlock.empty()) {
410     CC = ITBlock.back();
411     ITBlock.pop_back();
412   } else
413     CC = ARMCC::AL;
414 
415   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
416   MCInst::iterator I = MI.begin();
417   for (unsigned i = 0, e = MI.size(); i < e; ++i, ++I) {
418     if (OpInfo[i].isPredicate() ) {
419       I->setImm(CC);
420       ++I;
421       if (CC == ARMCC::AL)
422         I->setReg(0);
423       else
424         I->setReg(ARM::CPSR);
425       return;
426     }
427   }
428 }
429 
430 DecodeStatus ThumbDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
431                                                const MemoryObject &Region,
432                                                uint64_t Address,
433                                                raw_ostream &os) const {
434   uint8_t bytes[4];
435 
436   // We want to read exactly 2 bytes of data.
437   if (Region.readBytes(Address, 2, (uint8_t*)bytes, NULL) == -1)
438     return Fail;
439 
440   uint16_t insn16 = (bytes[1] << 8) | bytes[0];
441   DecodeStatus result = decodeThumbInstruction16(MI, insn16, Address, this);
442   if (result != Fail) {
443     Size = 2;
444     AddThumbPredicate(MI);
445     return result;
446   }
447 
448   MI.clear();
449   result = decodeThumbSBitInstruction16(MI, insn16, Address, this);
450   if (result) {
451     Size = 2;
452     bool InITBlock = !ITBlock.empty();
453     AddThumbPredicate(MI);
454     AddThumb1SBit(MI, InITBlock);
455     return result;
456   }
457 
458   MI.clear();
459   result = decodeThumb2Instruction16(MI, insn16, Address, this);
460   if (result != Fail) {
461     Size = 2;
462     AddThumbPredicate(MI);
463 
464     // If we find an IT instruction, we need to parse its condition
465     // code and mask operands so that we can apply them correctly
466     // to the subsequent instructions.
467     if (MI.getOpcode() == ARM::t2IT) {
468       unsigned firstcond = MI.getOperand(0).getImm();
469       uint32_t mask = MI.getOperand(1).getImm();
470       unsigned zeros = CountTrailingZeros_32(mask);
471       mask >>= zeros+1;
472 
473       for (unsigned i = 0; i < 4 - (zeros+1); ++i) {
474         if (firstcond ^ (mask & 1))
475           ITBlock.push_back(firstcond ^ 1);
476         else
477           ITBlock.push_back(firstcond);
478         mask >>= 1;
479       }
480       ITBlock.push_back(firstcond);
481     }
482 
483     return result;
484   }
485 
486   // We want to read exactly 4 bytes of data.
487   if (Region.readBytes(Address, 4, (uint8_t*)bytes, NULL) == -1)
488     return Fail;
489 
490   uint32_t insn32 = (bytes[3] <<  8) |
491                     (bytes[2] <<  0) |
492                     (bytes[1] << 24) |
493                     (bytes[0] << 16);
494   MI.clear();
495   result = decodeThumbInstruction32(MI, insn32, Address, this);
496   if (result != Fail) {
497     Size = 4;
498     bool InITBlock = ITBlock.size();
499     AddThumbPredicate(MI);
500     AddThumb1SBit(MI, InITBlock);
501     return result;
502   }
503 
504   MI.clear();
505   result = decodeThumb2Instruction32(MI, insn32, Address, this);
506   if (result != Fail) {
507     Size = 4;
508     AddThumbPredicate(MI);
509     return result;
510   }
511 
512   MI.clear();
513   result = decodeCommonInstruction32(MI, insn32, Address, this);
514   if (result != Fail) {
515     Size = 4;
516     AddThumbPredicate(MI);
517     return result;
518   }
519 
520   MI.clear();
521   result = decodeVFPInstruction32(MI, insn32, Address, this);
522   if (result != Fail) {
523     Size = 4;
524     UpdateThumbVFPPredicate(MI);
525     return result;
526   }
527 
528   MI.clear();
529   result = decodeNEONDupInstruction32(MI, insn32, Address, this);
530   if (result != Fail) {
531     Size = 4;
532     AddThumbPredicate(MI);
533     return result;
534   }
535 
536   if (fieldFromInstruction32(insn32, 24, 8) == 0xF9) {
537     MI.clear();
538     uint32_t NEONLdStInsn = insn32;
539     NEONLdStInsn &= 0xF0FFFFFF;
540     NEONLdStInsn |= 0x04000000;
541     result = decodeNEONLoadStoreInstruction32(MI, NEONLdStInsn, Address, this);
542     if (result != Fail) {
543       Size = 4;
544       AddThumbPredicate(MI);
545       return result;
546     }
547   }
548 
549   if (fieldFromInstruction32(insn32, 24, 4) == 0xF) {
550     MI.clear();
551     uint32_t NEONDataInsn = insn32;
552     NEONDataInsn &= 0xF0FFFFFF; // Clear bits 27-24
553     NEONDataInsn |= (NEONDataInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
554     NEONDataInsn |= 0x12000000; // Set bits 28 and 25
555     result = decodeNEONDataInstruction32(MI, NEONDataInsn, Address, this);
556     if (result != Fail) {
557       Size = 4;
558       AddThumbPredicate(MI);
559       return result;
560     }
561   }
562 
563   return Fail;
564 }
565 
566 
567 extern "C" void LLVMInitializeARMDisassembler() {
568   TargetRegistry::RegisterMCDisassembler(TheARMTarget,
569                                          createARMDisassembler);
570   TargetRegistry::RegisterMCDisassembler(TheThumbTarget,
571                                          createThumbDisassembler);
572 }
573 
574 static const unsigned GPRDecoderTable[] = {
575   ARM::R0, ARM::R1, ARM::R2, ARM::R3,
576   ARM::R4, ARM::R5, ARM::R6, ARM::R7,
577   ARM::R8, ARM::R9, ARM::R10, ARM::R11,
578   ARM::R12, ARM::SP, ARM::LR, ARM::PC
579 };
580 
581 static DecodeStatus DecodeGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
582                                    uint64_t Address, const void *Decoder) {
583   if (RegNo > 15)
584     return Fail;
585 
586   unsigned Register = GPRDecoderTable[RegNo];
587   Inst.addOperand(MCOperand::CreateReg(Register));
588   return Success;
589 }
590 
591 static DecodeStatus
592 DecodeGPRnopcRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
593                            uint64_t Address, const void *Decoder) {
594   if (RegNo == 15) return Fail;
595   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
596 }
597 
598 static DecodeStatus DecodetGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
599                                    uint64_t Address, const void *Decoder) {
600   if (RegNo > 7)
601     return Fail;
602   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
603 }
604 
605 static DecodeStatus DecodetcGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
606                                    uint64_t Address, const void *Decoder) {
607   unsigned Register = 0;
608   switch (RegNo) {
609     case 0:
610       Register = ARM::R0;
611       break;
612     case 1:
613       Register = ARM::R1;
614       break;
615     case 2:
616       Register = ARM::R2;
617       break;
618     case 3:
619       Register = ARM::R3;
620       break;
621     case 9:
622       Register = ARM::R9;
623       break;
624     case 12:
625       Register = ARM::R12;
626       break;
627     default:
628       return Fail;
629     }
630 
631   Inst.addOperand(MCOperand::CreateReg(Register));
632   return Success;
633 }
634 
635 static DecodeStatus DecoderGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
636                                    uint64_t Address, const void *Decoder) {
637   if (RegNo == 13 || RegNo == 15) return Fail;
638   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
639 }
640 
641 static const unsigned SPRDecoderTable[] = {
642      ARM::S0,  ARM::S1,  ARM::S2,  ARM::S3,
643      ARM::S4,  ARM::S5,  ARM::S6,  ARM::S7,
644      ARM::S8,  ARM::S9, ARM::S10, ARM::S11,
645     ARM::S12, ARM::S13, ARM::S14, ARM::S15,
646     ARM::S16, ARM::S17, ARM::S18, ARM::S19,
647     ARM::S20, ARM::S21, ARM::S22, ARM::S23,
648     ARM::S24, ARM::S25, ARM::S26, ARM::S27,
649     ARM::S28, ARM::S29, ARM::S30, ARM::S31
650 };
651 
652 static DecodeStatus DecodeSPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
653                                    uint64_t Address, const void *Decoder) {
654   if (RegNo > 31)
655     return Fail;
656 
657   unsigned Register = SPRDecoderTable[RegNo];
658   Inst.addOperand(MCOperand::CreateReg(Register));
659   return Success;
660 }
661 
662 static const unsigned DPRDecoderTable[] = {
663      ARM::D0,  ARM::D1,  ARM::D2,  ARM::D3,
664      ARM::D4,  ARM::D5,  ARM::D6,  ARM::D7,
665      ARM::D8,  ARM::D9, ARM::D10, ARM::D11,
666     ARM::D12, ARM::D13, ARM::D14, ARM::D15,
667     ARM::D16, ARM::D17, ARM::D18, ARM::D19,
668     ARM::D20, ARM::D21, ARM::D22, ARM::D23,
669     ARM::D24, ARM::D25, ARM::D26, ARM::D27,
670     ARM::D28, ARM::D29, ARM::D30, ARM::D31
671 };
672 
673 static DecodeStatus DecodeDPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
674                                    uint64_t Address, const void *Decoder) {
675   if (RegNo > 31)
676     return Fail;
677 
678   unsigned Register = DPRDecoderTable[RegNo];
679   Inst.addOperand(MCOperand::CreateReg(Register));
680   return Success;
681 }
682 
683 static DecodeStatus DecodeDPR_8RegisterClass(llvm::MCInst &Inst, unsigned RegNo,
684                                    uint64_t Address, const void *Decoder) {
685   if (RegNo > 7)
686     return Fail;
687   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
688 }
689 
690 static DecodeStatus
691 DecodeDPR_VFP2RegisterClass(llvm::MCInst &Inst, unsigned RegNo,
692                             uint64_t Address, const void *Decoder) {
693   if (RegNo > 15)
694     return Fail;
695   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
696 }
697 
698 static const unsigned QPRDecoderTable[] = {
699      ARM::Q0,  ARM::Q1,  ARM::Q2,  ARM::Q3,
700      ARM::Q4,  ARM::Q5,  ARM::Q6,  ARM::Q7,
701      ARM::Q8,  ARM::Q9, ARM::Q10, ARM::Q11,
702     ARM::Q12, ARM::Q13, ARM::Q14, ARM::Q15
703 };
704 
705 
706 static DecodeStatus DecodeQPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
707                                    uint64_t Address, const void *Decoder) {
708   if (RegNo > 31)
709     return Fail;
710   RegNo >>= 1;
711 
712   unsigned Register = QPRDecoderTable[RegNo];
713   Inst.addOperand(MCOperand::CreateReg(Register));
714   return Success;
715 }
716 
717 static DecodeStatus DecodePredicateOperand(llvm::MCInst &Inst, unsigned Val,
718                                uint64_t Address, const void *Decoder) {
719   if (Val == 0xF) return Fail;
720   // AL predicate is not allowed on Thumb1 branches.
721   if (Inst.getOpcode() == ARM::tBcc && Val == 0xE)
722     return Fail;
723   Inst.addOperand(MCOperand::CreateImm(Val));
724   if (Val == ARMCC::AL) {
725     Inst.addOperand(MCOperand::CreateReg(0));
726   } else
727     Inst.addOperand(MCOperand::CreateReg(ARM::CPSR));
728   return Success;
729 }
730 
731 static DecodeStatus DecodeCCOutOperand(llvm::MCInst &Inst, unsigned Val,
732                                uint64_t Address, const void *Decoder) {
733   if (Val)
734     Inst.addOperand(MCOperand::CreateReg(ARM::CPSR));
735   else
736     Inst.addOperand(MCOperand::CreateReg(0));
737   return Success;
738 }
739 
740 static DecodeStatus DecodeSOImmOperand(llvm::MCInst &Inst, unsigned Val,
741                                uint64_t Address, const void *Decoder) {
742   uint32_t imm = Val & 0xFF;
743   uint32_t rot = (Val & 0xF00) >> 7;
744   uint32_t rot_imm = (imm >> rot) | (imm << (32-rot));
745   Inst.addOperand(MCOperand::CreateImm(rot_imm));
746   return Success;
747 }
748 
749 static DecodeStatus DecodeBLTargetOperand(llvm::MCInst &Inst, unsigned Val,
750                                uint64_t Address, const void *Decoder) {
751   Val <<= 2;
752   Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(Val)));
753   return Success;
754 }
755 
756 static DecodeStatus DecodeSORegImmOperand(llvm::MCInst &Inst, unsigned Val,
757                                uint64_t Address, const void *Decoder) {
758   DecodeStatus S = Success;
759 
760   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
761   unsigned type = fieldFromInstruction32(Val, 5, 2);
762   unsigned imm = fieldFromInstruction32(Val, 7, 5);
763 
764   // Register-immediate
765   CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
766 
767   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
768   switch (type) {
769     case 0:
770       Shift = ARM_AM::lsl;
771       break;
772     case 1:
773       Shift = ARM_AM::lsr;
774       break;
775     case 2:
776       Shift = ARM_AM::asr;
777       break;
778     case 3:
779       Shift = ARM_AM::ror;
780       break;
781   }
782 
783   if (Shift == ARM_AM::ror && imm == 0)
784     Shift = ARM_AM::rrx;
785 
786   unsigned Op = Shift | (imm << 3);
787   Inst.addOperand(MCOperand::CreateImm(Op));
788 
789   return S;
790 }
791 
792 static DecodeStatus DecodeSORegRegOperand(llvm::MCInst &Inst, unsigned Val,
793                                uint64_t Address, const void *Decoder) {
794   DecodeStatus S = Success;
795 
796   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
797   unsigned type = fieldFromInstruction32(Val, 5, 2);
798   unsigned Rs = fieldFromInstruction32(Val, 8, 4);
799 
800   // Register-register
801   CHECK(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder));
802   CHECK(S, DecodeGPRnopcRegisterClass(Inst, Rs, Address, Decoder));
803 
804   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
805   switch (type) {
806     case 0:
807       Shift = ARM_AM::lsl;
808       break;
809     case 1:
810       Shift = ARM_AM::lsr;
811       break;
812     case 2:
813       Shift = ARM_AM::asr;
814       break;
815     case 3:
816       Shift = ARM_AM::ror;
817       break;
818   }
819 
820   Inst.addOperand(MCOperand::CreateImm(Shift));
821 
822   return S;
823 }
824 
825 static DecodeStatus DecodeRegListOperand(llvm::MCInst &Inst, unsigned Val,
826                                  uint64_t Address, const void *Decoder) {
827   DecodeStatus S = Success;
828 
829   // Empty register lists are not allowed.
830   if (CountPopulation_32(Val) == 0) return Fail;
831   for (unsigned i = 0; i < 16; ++i) {
832     if (Val & (1 << i)) {
833       CHECK(S, DecodeGPRRegisterClass(Inst, i, Address, Decoder));
834     }
835   }
836 
837   return S;
838 }
839 
840 static DecodeStatus DecodeSPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
841                                  uint64_t Address, const void *Decoder) {
842   DecodeStatus S = Success;
843 
844   unsigned Vd = fieldFromInstruction32(Val, 8, 4);
845   unsigned regs = Val & 0xFF;
846 
847   CHECK(S, DecodeSPRRegisterClass(Inst, Vd, Address, Decoder));
848   for (unsigned i = 0; i < (regs - 1); ++i) {
849     CHECK(S, DecodeSPRRegisterClass(Inst, ++Vd, Address, Decoder));
850   }
851 
852   return S;
853 }
854 
855 static DecodeStatus DecodeDPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
856                                  uint64_t Address, const void *Decoder) {
857   DecodeStatus S = Success;
858 
859   unsigned Vd = fieldFromInstruction32(Val, 8, 4);
860   unsigned regs = (Val & 0xFF) / 2;
861 
862   CHECK(S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder));
863   for (unsigned i = 0; i < (regs - 1); ++i) {
864     CHECK(S, DecodeDPRRegisterClass(Inst, ++Vd, Address, Decoder));
865   }
866 
867   return S;
868 }
869 
870 static DecodeStatus DecodeBitfieldMaskOperand(llvm::MCInst &Inst, unsigned Val,
871                                       uint64_t Address, const void *Decoder) {
872   // This operand encodes a mask of contiguous zeros between a specified MSB
873   // and LSB.  To decode it, we create the mask of all bits MSB-and-lower,
874   // the mask of all bits LSB-and-lower, and then xor them to create
875   // the mask of that's all ones on [msb, lsb].  Finally we not it to
876   // create the final mask.
877   unsigned msb = fieldFromInstruction32(Val, 5, 5);
878   unsigned lsb = fieldFromInstruction32(Val, 0, 5);
879   uint32_t msb_mask = (1 << (msb+1)) - 1;
880   uint32_t lsb_mask = (1 << lsb) - 1;
881   Inst.addOperand(MCOperand::CreateImm(~(msb_mask ^ lsb_mask)));
882   return Success;
883 }
884 
885 static DecodeStatus DecodeCopMemInstruction(llvm::MCInst &Inst, unsigned Insn,
886                                   uint64_t Address, const void *Decoder) {
887   DecodeStatus S = Success;
888 
889   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
890   unsigned CRd = fieldFromInstruction32(Insn, 12, 4);
891   unsigned coproc = fieldFromInstruction32(Insn, 8, 4);
892   unsigned imm = fieldFromInstruction32(Insn, 0, 8);
893   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
894   unsigned U = fieldFromInstruction32(Insn, 23, 1);
895 
896   switch (Inst.getOpcode()) {
897     case ARM::LDC_OFFSET:
898     case ARM::LDC_PRE:
899     case ARM::LDC_POST:
900     case ARM::LDC_OPTION:
901     case ARM::LDCL_OFFSET:
902     case ARM::LDCL_PRE:
903     case ARM::LDCL_POST:
904     case ARM::LDCL_OPTION:
905     case ARM::STC_OFFSET:
906     case ARM::STC_PRE:
907     case ARM::STC_POST:
908     case ARM::STC_OPTION:
909     case ARM::STCL_OFFSET:
910     case ARM::STCL_PRE:
911     case ARM::STCL_POST:
912     case ARM::STCL_OPTION:
913       if (coproc == 0xA || coproc == 0xB)
914         return Fail;
915       break;
916     default:
917       break;
918   }
919 
920   Inst.addOperand(MCOperand::CreateImm(coproc));
921   Inst.addOperand(MCOperand::CreateImm(CRd));
922   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
923   switch (Inst.getOpcode()) {
924     case ARM::LDC_OPTION:
925     case ARM::LDCL_OPTION:
926     case ARM::LDC2_OPTION:
927     case ARM::LDC2L_OPTION:
928     case ARM::STC_OPTION:
929     case ARM::STCL_OPTION:
930     case ARM::STC2_OPTION:
931     case ARM::STC2L_OPTION:
932     case ARM::LDCL_POST:
933     case ARM::STCL_POST:
934     case ARM::LDC2L_POST:
935     case ARM::STC2L_POST:
936       break;
937     default:
938       Inst.addOperand(MCOperand::CreateReg(0));
939       break;
940   }
941 
942   unsigned P = fieldFromInstruction32(Insn, 24, 1);
943   unsigned W = fieldFromInstruction32(Insn, 21, 1);
944 
945   bool writeback = (P == 0) || (W == 1);
946   unsigned idx_mode = 0;
947   if (P && writeback)
948     idx_mode = ARMII::IndexModePre;
949   else if (!P && writeback)
950     idx_mode = ARMII::IndexModePost;
951 
952   switch (Inst.getOpcode()) {
953     case ARM::LDCL_POST:
954     case ARM::STCL_POST:
955     case ARM::LDC2L_POST:
956     case ARM::STC2L_POST:
957       imm |= U << 8;
958     case ARM::LDC_OPTION:
959     case ARM::LDCL_OPTION:
960     case ARM::LDC2_OPTION:
961     case ARM::LDC2L_OPTION:
962     case ARM::STC_OPTION:
963     case ARM::STCL_OPTION:
964     case ARM::STC2_OPTION:
965     case ARM::STC2L_OPTION:
966       Inst.addOperand(MCOperand::CreateImm(imm));
967       break;
968     default:
969       if (U)
970         Inst.addOperand(MCOperand::CreateImm(
971             ARM_AM::getAM2Opc(ARM_AM::add, imm, ARM_AM::lsl, idx_mode)));
972       else
973         Inst.addOperand(MCOperand::CreateImm(
974             ARM_AM::getAM2Opc(ARM_AM::sub, imm, ARM_AM::lsl, idx_mode)));
975       break;
976   }
977 
978   switch (Inst.getOpcode()) {
979     case ARM::LDC_OFFSET:
980     case ARM::LDC_PRE:
981     case ARM::LDC_POST:
982     case ARM::LDC_OPTION:
983     case ARM::LDCL_OFFSET:
984     case ARM::LDCL_PRE:
985     case ARM::LDCL_POST:
986     case ARM::LDCL_OPTION:
987     case ARM::STC_OFFSET:
988     case ARM::STC_PRE:
989     case ARM::STC_POST:
990     case ARM::STC_OPTION:
991     case ARM::STCL_OFFSET:
992     case ARM::STCL_PRE:
993     case ARM::STCL_POST:
994     case ARM::STCL_OPTION:
995       CHECK(S, DecodePredicateOperand(Inst, pred, Address, Decoder));
996       break;
997     default:
998       break;
999   }
1000 
1001   return S;
1002 }
1003 
1004 static DecodeStatus
1005 DecodeAddrMode2IdxInstruction(llvm::MCInst &Inst, unsigned Insn,
1006                               uint64_t Address, const void *Decoder) {
1007   DecodeStatus S = Success;
1008 
1009   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1010   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
1011   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1012   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
1013   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1014   unsigned reg = fieldFromInstruction32(Insn, 25, 1);
1015   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1016   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1017 
1018   // On stores, the writeback operand precedes Rt.
1019   switch (Inst.getOpcode()) {
1020     case ARM::STR_POST_IMM:
1021     case ARM::STR_POST_REG:
1022     case ARM::STRB_POST_IMM:
1023     case ARM::STRB_POST_REG:
1024     case ARM::STRT_POST_REG:
1025     case ARM::STRT_POST_IMM:
1026     case ARM::STRBT_POST_REG:
1027     case ARM::STRBT_POST_IMM:
1028       CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
1029       break;
1030     default:
1031       break;
1032   }
1033 
1034   CHECK(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder));
1035 
1036   // On loads, the writeback operand comes after Rt.
1037   switch (Inst.getOpcode()) {
1038     case ARM::LDR_POST_IMM:
1039     case ARM::LDR_POST_REG:
1040     case ARM::LDRB_POST_IMM:
1041     case ARM::LDRB_POST_REG:
1042     case ARM::LDR_PRE:
1043     case ARM::LDRB_PRE:
1044     case ARM::LDRBT_POST_REG:
1045     case ARM::LDRBT_POST_IMM:
1046     case ARM::LDRT_POST_REG:
1047     case ARM::LDRT_POST_IMM:
1048       CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
1049       break;
1050     default:
1051       break;
1052   }
1053 
1054   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
1055 
1056   ARM_AM::AddrOpc Op = ARM_AM::add;
1057   if (!fieldFromInstruction32(Insn, 23, 1))
1058     Op = ARM_AM::sub;
1059 
1060   bool writeback = (P == 0) || (W == 1);
1061   unsigned idx_mode = 0;
1062   if (P && writeback)
1063     idx_mode = ARMII::IndexModePre;
1064   else if (!P && writeback)
1065     idx_mode = ARMII::IndexModePost;
1066 
1067   if (writeback && (Rn == 15 || Rn == Rt)) S = Unpredictable; // UNPREDICTABLE
1068 
1069   if (reg) {
1070     CHECK(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder));
1071     ARM_AM::ShiftOpc Opc = ARM_AM::lsl;
1072     switch( fieldFromInstruction32(Insn, 5, 2)) {
1073       case 0:
1074         Opc = ARM_AM::lsl;
1075         break;
1076       case 1:
1077         Opc = ARM_AM::lsr;
1078         break;
1079       case 2:
1080         Opc = ARM_AM::asr;
1081         break;
1082       case 3:
1083         Opc = ARM_AM::ror;
1084         break;
1085       default:
1086         return Fail;
1087     }
1088     unsigned amt = fieldFromInstruction32(Insn, 7, 5);
1089     unsigned imm = ARM_AM::getAM2Opc(Op, amt, Opc, idx_mode);
1090 
1091     Inst.addOperand(MCOperand::CreateImm(imm));
1092   } else {
1093     Inst.addOperand(MCOperand::CreateReg(0));
1094     unsigned tmp = ARM_AM::getAM2Opc(Op, imm, ARM_AM::lsl, idx_mode);
1095     Inst.addOperand(MCOperand::CreateImm(tmp));
1096   }
1097 
1098   CHECK(S, DecodePredicateOperand(Inst, pred, Address, Decoder));
1099 
1100   return S;
1101 }
1102 
1103 static DecodeStatus DecodeSORegMemOperand(llvm::MCInst &Inst, unsigned Val,
1104                                   uint64_t Address, const void *Decoder) {
1105   DecodeStatus S = Success;
1106 
1107   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
1108   unsigned Rm = fieldFromInstruction32(Val,  0, 4);
1109   unsigned type = fieldFromInstruction32(Val, 5, 2);
1110   unsigned imm = fieldFromInstruction32(Val, 7, 5);
1111   unsigned U = fieldFromInstruction32(Val, 12, 1);
1112 
1113   ARM_AM::ShiftOpc ShOp = ARM_AM::lsl;
1114   switch (type) {
1115     case 0:
1116       ShOp = ARM_AM::lsl;
1117       break;
1118     case 1:
1119       ShOp = ARM_AM::lsr;
1120       break;
1121     case 2:
1122       ShOp = ARM_AM::asr;
1123       break;
1124     case 3:
1125       ShOp = ARM_AM::ror;
1126       break;
1127   }
1128 
1129   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
1130   CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
1131   unsigned shift;
1132   if (U)
1133     shift = ARM_AM::getAM2Opc(ARM_AM::add, imm, ShOp);
1134   else
1135     shift = ARM_AM::getAM2Opc(ARM_AM::sub, imm, ShOp);
1136   Inst.addOperand(MCOperand::CreateImm(shift));
1137 
1138   return S;
1139 }
1140 
1141 static DecodeStatus
1142 DecodeAddrMode3Instruction(llvm::MCInst &Inst, unsigned Insn,
1143                            uint64_t Address, const void *Decoder) {
1144   DecodeStatus S = Success;
1145 
1146   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
1147   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1148   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1149   unsigned type = fieldFromInstruction32(Insn, 22, 1);
1150   unsigned imm = fieldFromInstruction32(Insn, 8, 4);
1151   unsigned U = ((~fieldFromInstruction32(Insn, 23, 1)) & 1) << 8;
1152   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1153   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1154   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1155 
1156   bool writeback = (W == 1) | (P == 0);
1157 
1158   // For {LD,ST}RD, Rt must be even, else undefined.
1159   switch (Inst.getOpcode()) {
1160     case ARM::STRD:
1161     case ARM::STRD_PRE:
1162     case ARM::STRD_POST:
1163     case ARM::LDRD:
1164     case ARM::LDRD_PRE:
1165     case ARM::LDRD_POST:
1166       if (Rt & 0x1) return Fail;
1167       break;
1168   default:
1169     break;
1170   }
1171 
1172   if (writeback) { // Writeback
1173     if (P)
1174       U |= ARMII::IndexModePre << 9;
1175     else
1176       U |= ARMII::IndexModePost << 9;
1177 
1178     // On stores, the writeback operand precedes Rt.
1179     switch (Inst.getOpcode()) {
1180     case ARM::STRD:
1181     case ARM::STRD_PRE:
1182     case ARM::STRD_POST:
1183     case ARM::STRH:
1184     case ARM::STRH_PRE:
1185     case ARM::STRH_POST:
1186       CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
1187       break;
1188     default:
1189       break;
1190     }
1191   }
1192 
1193   CHECK(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder));
1194   switch (Inst.getOpcode()) {
1195     case ARM::STRD:
1196     case ARM::STRD_PRE:
1197     case ARM::STRD_POST:
1198     case ARM::LDRD:
1199     case ARM::LDRD_PRE:
1200     case ARM::LDRD_POST:
1201       CHECK(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder));
1202       break;
1203     default:
1204       break;
1205   }
1206 
1207   if (writeback) {
1208     // On loads, the writeback operand comes after Rt.
1209     switch (Inst.getOpcode()) {
1210     case ARM::LDRD:
1211     case ARM::LDRD_PRE:
1212     case ARM::LDRD_POST:
1213     case ARM::LDRH:
1214     case ARM::LDRH_PRE:
1215     case ARM::LDRH_POST:
1216     case ARM::LDRSH:
1217     case ARM::LDRSH_PRE:
1218     case ARM::LDRSH_POST:
1219     case ARM::LDRSB:
1220     case ARM::LDRSB_PRE:
1221     case ARM::LDRSB_POST:
1222     case ARM::LDRHTr:
1223     case ARM::LDRSBTr:
1224       CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
1225       break;
1226     default:
1227       break;
1228     }
1229   }
1230 
1231   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
1232 
1233   if (type) {
1234     Inst.addOperand(MCOperand::CreateReg(0));
1235     Inst.addOperand(MCOperand::CreateImm(U | (imm << 4) | Rm));
1236   } else {
1237     CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
1238     Inst.addOperand(MCOperand::CreateImm(U));
1239   }
1240 
1241   CHECK(S, DecodePredicateOperand(Inst, pred, Address, Decoder));
1242 
1243   return S;
1244 }
1245 
1246 static DecodeStatus DecodeRFEInstruction(llvm::MCInst &Inst, unsigned Insn,
1247                                  uint64_t Address, const void *Decoder) {
1248   DecodeStatus S = Success;
1249 
1250   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1251   unsigned mode = fieldFromInstruction32(Insn, 23, 2);
1252 
1253   switch (mode) {
1254     case 0:
1255       mode = ARM_AM::da;
1256       break;
1257     case 1:
1258       mode = ARM_AM::ia;
1259       break;
1260     case 2:
1261       mode = ARM_AM::db;
1262       break;
1263     case 3:
1264       mode = ARM_AM::ib;
1265       break;
1266   }
1267 
1268   Inst.addOperand(MCOperand::CreateImm(mode));
1269   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
1270 
1271   return S;
1272 }
1273 
1274 static DecodeStatus DecodeMemMultipleWritebackInstruction(llvm::MCInst &Inst,
1275                                   unsigned Insn,
1276                                   uint64_t Address, const void *Decoder) {
1277   DecodeStatus S = Success;
1278 
1279   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1280   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1281   unsigned reglist = fieldFromInstruction32(Insn, 0, 16);
1282 
1283   if (pred == 0xF) {
1284     switch (Inst.getOpcode()) {
1285       case ARM::LDMDA:
1286         Inst.setOpcode(ARM::RFEDA);
1287         break;
1288       case ARM::LDMDA_UPD:
1289         Inst.setOpcode(ARM::RFEDA_UPD);
1290         break;
1291       case ARM::LDMDB:
1292         Inst.setOpcode(ARM::RFEDB);
1293         break;
1294       case ARM::LDMDB_UPD:
1295         Inst.setOpcode(ARM::RFEDB_UPD);
1296         break;
1297       case ARM::LDMIA:
1298         Inst.setOpcode(ARM::RFEIA);
1299         break;
1300       case ARM::LDMIA_UPD:
1301         Inst.setOpcode(ARM::RFEIA_UPD);
1302         break;
1303       case ARM::LDMIB:
1304         Inst.setOpcode(ARM::RFEIB);
1305         break;
1306       case ARM::LDMIB_UPD:
1307         Inst.setOpcode(ARM::RFEIB_UPD);
1308         break;
1309       case ARM::STMDA:
1310         Inst.setOpcode(ARM::SRSDA);
1311         break;
1312       case ARM::STMDA_UPD:
1313         Inst.setOpcode(ARM::SRSDA_UPD);
1314         break;
1315       case ARM::STMDB:
1316         Inst.setOpcode(ARM::SRSDB);
1317         break;
1318       case ARM::STMDB_UPD:
1319         Inst.setOpcode(ARM::SRSDB_UPD);
1320         break;
1321       case ARM::STMIA:
1322         Inst.setOpcode(ARM::SRSIA);
1323         break;
1324       case ARM::STMIA_UPD:
1325         Inst.setOpcode(ARM::SRSIA_UPD);
1326         break;
1327       case ARM::STMIB:
1328         Inst.setOpcode(ARM::SRSIB);
1329         break;
1330       case ARM::STMIB_UPD:
1331         Inst.setOpcode(ARM::SRSIB_UPD);
1332         break;
1333       default:
1334         CHECK(S, Fail);
1335     }
1336 
1337     // For stores (which become SRS's, the only operand is the mode.
1338     if (fieldFromInstruction32(Insn, 20, 1) == 0) {
1339       Inst.addOperand(
1340           MCOperand::CreateImm(fieldFromInstruction32(Insn, 0, 4)));
1341       return S;
1342     }
1343 
1344     return DecodeRFEInstruction(Inst, Insn, Address, Decoder);
1345   }
1346 
1347   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
1348   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)); // Tied
1349   CHECK(S, DecodePredicateOperand(Inst, pred, Address, Decoder));
1350   CHECK(S, DecodeRegListOperand(Inst, reglist, Address, Decoder));
1351 
1352   return S;
1353 }
1354 
1355 static DecodeStatus DecodeCPSInstruction(llvm::MCInst &Inst, unsigned Insn,
1356                                  uint64_t Address, const void *Decoder) {
1357   unsigned imod = fieldFromInstruction32(Insn, 18, 2);
1358   unsigned M = fieldFromInstruction32(Insn, 17, 1);
1359   unsigned iflags = fieldFromInstruction32(Insn, 6, 3);
1360   unsigned mode = fieldFromInstruction32(Insn, 0, 5);
1361 
1362   DecodeStatus S = Success;
1363 
1364   // imod == '01' --> UNPREDICTABLE
1365   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
1366   // return failure here.  The '01' imod value is unprintable, so there's
1367   // nothing useful we could do even if we returned UNPREDICTABLE.
1368 
1369   if (imod == 1) CHECK(S, Fail);
1370 
1371   if (imod && M) {
1372     Inst.setOpcode(ARM::CPS3p);
1373     Inst.addOperand(MCOperand::CreateImm(imod));
1374     Inst.addOperand(MCOperand::CreateImm(iflags));
1375     Inst.addOperand(MCOperand::CreateImm(mode));
1376   } else if (imod && !M) {
1377     Inst.setOpcode(ARM::CPS2p);
1378     Inst.addOperand(MCOperand::CreateImm(imod));
1379     Inst.addOperand(MCOperand::CreateImm(iflags));
1380     if (mode) CHECK(S, Unpredictable);
1381   } else if (!imod && M) {
1382     Inst.setOpcode(ARM::CPS1p);
1383     Inst.addOperand(MCOperand::CreateImm(mode));
1384     if (iflags) CHECK(S, Unpredictable);
1385   } else {
1386     // imod == '00' && M == '0' --> UNPREDICTABLE
1387     Inst.setOpcode(ARM::CPS1p);
1388     Inst.addOperand(MCOperand::CreateImm(mode));
1389     CHECK(S, Unpredictable);
1390   }
1391 
1392   return S;
1393 }
1394 
1395 static DecodeStatus DecodeSMLAInstruction(llvm::MCInst &Inst, unsigned Insn,
1396                                  uint64_t Address, const void *Decoder) {
1397   DecodeStatus S = Success;
1398 
1399   unsigned Rd = fieldFromInstruction32(Insn, 16, 4);
1400   unsigned Rn = fieldFromInstruction32(Insn, 0, 4);
1401   unsigned Rm = fieldFromInstruction32(Insn, 8, 4);
1402   unsigned Ra = fieldFromInstruction32(Insn, 12, 4);
1403   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1404 
1405   if (pred == 0xF)
1406     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
1407 
1408   CHECK(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder));
1409   CHECK(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder));
1410   CHECK(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder));
1411   CHECK(S, DecodeGPRnopcRegisterClass(Inst, Ra, Address, Decoder));
1412 
1413   CHECK(S, DecodePredicateOperand(Inst, pred, Address, Decoder));
1414 
1415   return S;
1416 }
1417 
1418 static DecodeStatus DecodeAddrModeImm12Operand(llvm::MCInst &Inst, unsigned Val,
1419                            uint64_t Address, const void *Decoder) {
1420   DecodeStatus S = Success;
1421 
1422   unsigned add = fieldFromInstruction32(Val, 12, 1);
1423   unsigned imm = fieldFromInstruction32(Val, 0, 12);
1424   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
1425 
1426   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
1427 
1428   if (!add) imm *= -1;
1429   if (imm == 0 && !add) imm = INT32_MIN;
1430   Inst.addOperand(MCOperand::CreateImm(imm));
1431 
1432   return S;
1433 }
1434 
1435 static DecodeStatus DecodeAddrMode5Operand(llvm::MCInst &Inst, unsigned Val,
1436                                    uint64_t Address, const void *Decoder) {
1437   DecodeStatus S = Success;
1438 
1439   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
1440   unsigned U = fieldFromInstruction32(Val, 8, 1);
1441   unsigned imm = fieldFromInstruction32(Val, 0, 8);
1442 
1443   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
1444 
1445   if (U)
1446     Inst.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(ARM_AM::add, imm)));
1447   else
1448     Inst.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(ARM_AM::sub, imm)));
1449 
1450   return S;
1451 }
1452 
1453 static DecodeStatus DecodeAddrMode7Operand(llvm::MCInst &Inst, unsigned Val,
1454                                    uint64_t Address, const void *Decoder) {
1455   return DecodeGPRRegisterClass(Inst, Val, Address, Decoder);
1456 }
1457 
1458 static DecodeStatus
1459 DecodeBranchImmInstruction(llvm::MCInst &Inst, unsigned Insn,
1460                            uint64_t Address, const void *Decoder) {
1461   DecodeStatus S = Success;
1462 
1463   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1464   unsigned imm = fieldFromInstruction32(Insn, 0, 24) << 2;
1465 
1466   if (pred == 0xF) {
1467     Inst.setOpcode(ARM::BLXi);
1468     imm |= fieldFromInstruction32(Insn, 24, 1) << 1;
1469     Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(imm)));
1470     return S;
1471   }
1472 
1473   Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(imm)));
1474   CHECK(S, DecodePredicateOperand(Inst, pred, Address, Decoder));
1475 
1476   return S;
1477 }
1478 
1479 
1480 static DecodeStatus DecodeVCVTImmOperand(llvm::MCInst &Inst, unsigned Val,
1481                                  uint64_t Address, const void *Decoder) {
1482   Inst.addOperand(MCOperand::CreateImm(64 - Val));
1483   return Success;
1484 }
1485 
1486 static DecodeStatus DecodeAddrMode6Operand(llvm::MCInst &Inst, unsigned Val,
1487                                    uint64_t Address, const void *Decoder) {
1488   DecodeStatus S = Success;
1489 
1490   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
1491   unsigned align = fieldFromInstruction32(Val, 4, 2);
1492 
1493   CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
1494   if (!align)
1495     Inst.addOperand(MCOperand::CreateImm(0));
1496   else
1497     Inst.addOperand(MCOperand::CreateImm(4 << align));
1498 
1499   return S;
1500 }
1501 
1502 static DecodeStatus DecodeVLDInstruction(llvm::MCInst &Inst, unsigned Insn,
1503                                    uint64_t Address, const void *Decoder) {
1504   DecodeStatus S = Success;
1505 
1506   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
1507   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
1508   unsigned wb = fieldFromInstruction32(Insn, 16, 4);
1509   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1510   Rn |= fieldFromInstruction32(Insn, 4, 2) << 4;
1511   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1512 
1513   // First output register
1514   CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
1515 
1516   // Second output register
1517   switch (Inst.getOpcode()) {
1518     case ARM::VLD1q8:
1519     case ARM::VLD1q16:
1520     case ARM::VLD1q32:
1521     case ARM::VLD1q64:
1522     case ARM::VLD1q8_UPD:
1523     case ARM::VLD1q16_UPD:
1524     case ARM::VLD1q32_UPD:
1525     case ARM::VLD1q64_UPD:
1526     case ARM::VLD1d8T:
1527     case ARM::VLD1d16T:
1528     case ARM::VLD1d32T:
1529     case ARM::VLD1d64T:
1530     case ARM::VLD1d8T_UPD:
1531     case ARM::VLD1d16T_UPD:
1532     case ARM::VLD1d32T_UPD:
1533     case ARM::VLD1d64T_UPD:
1534     case ARM::VLD1d8Q:
1535     case ARM::VLD1d16Q:
1536     case ARM::VLD1d32Q:
1537     case ARM::VLD1d64Q:
1538     case ARM::VLD1d8Q_UPD:
1539     case ARM::VLD1d16Q_UPD:
1540     case ARM::VLD1d32Q_UPD:
1541     case ARM::VLD1d64Q_UPD:
1542     case ARM::VLD2d8:
1543     case ARM::VLD2d16:
1544     case ARM::VLD2d32:
1545     case ARM::VLD2d8_UPD:
1546     case ARM::VLD2d16_UPD:
1547     case ARM::VLD2d32_UPD:
1548     case ARM::VLD2q8:
1549     case ARM::VLD2q16:
1550     case ARM::VLD2q32:
1551     case ARM::VLD2q8_UPD:
1552     case ARM::VLD2q16_UPD:
1553     case ARM::VLD2q32_UPD:
1554     case ARM::VLD3d8:
1555     case ARM::VLD3d16:
1556     case ARM::VLD3d32:
1557     case ARM::VLD3d8_UPD:
1558     case ARM::VLD3d16_UPD:
1559     case ARM::VLD3d32_UPD:
1560     case ARM::VLD4d8:
1561     case ARM::VLD4d16:
1562     case ARM::VLD4d32:
1563     case ARM::VLD4d8_UPD:
1564     case ARM::VLD4d16_UPD:
1565     case ARM::VLD4d32_UPD:
1566       CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder));
1567       break;
1568     case ARM::VLD2b8:
1569     case ARM::VLD2b16:
1570     case ARM::VLD2b32:
1571     case ARM::VLD2b8_UPD:
1572     case ARM::VLD2b16_UPD:
1573     case ARM::VLD2b32_UPD:
1574     case ARM::VLD3q8:
1575     case ARM::VLD3q16:
1576     case ARM::VLD3q32:
1577     case ARM::VLD3q8_UPD:
1578     case ARM::VLD3q16_UPD:
1579     case ARM::VLD3q32_UPD:
1580     case ARM::VLD4q8:
1581     case ARM::VLD4q16:
1582     case ARM::VLD4q32:
1583     case ARM::VLD4q8_UPD:
1584     case ARM::VLD4q16_UPD:
1585     case ARM::VLD4q32_UPD:
1586       CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder));
1587     default:
1588       break;
1589   }
1590 
1591   // Third output register
1592   switch(Inst.getOpcode()) {
1593     case ARM::VLD1d8T:
1594     case ARM::VLD1d16T:
1595     case ARM::VLD1d32T:
1596     case ARM::VLD1d64T:
1597     case ARM::VLD1d8T_UPD:
1598     case ARM::VLD1d16T_UPD:
1599     case ARM::VLD1d32T_UPD:
1600     case ARM::VLD1d64T_UPD:
1601     case ARM::VLD1d8Q:
1602     case ARM::VLD1d16Q:
1603     case ARM::VLD1d32Q:
1604     case ARM::VLD1d64Q:
1605     case ARM::VLD1d8Q_UPD:
1606     case ARM::VLD1d16Q_UPD:
1607     case ARM::VLD1d32Q_UPD:
1608     case ARM::VLD1d64Q_UPD:
1609     case ARM::VLD2q8:
1610     case ARM::VLD2q16:
1611     case ARM::VLD2q32:
1612     case ARM::VLD2q8_UPD:
1613     case ARM::VLD2q16_UPD:
1614     case ARM::VLD2q32_UPD:
1615     case ARM::VLD3d8:
1616     case ARM::VLD3d16:
1617     case ARM::VLD3d32:
1618     case ARM::VLD3d8_UPD:
1619     case ARM::VLD3d16_UPD:
1620     case ARM::VLD3d32_UPD:
1621     case ARM::VLD4d8:
1622     case ARM::VLD4d16:
1623     case ARM::VLD4d32:
1624     case ARM::VLD4d8_UPD:
1625     case ARM::VLD4d16_UPD:
1626     case ARM::VLD4d32_UPD:
1627       CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder));
1628       break;
1629     case ARM::VLD3q8:
1630     case ARM::VLD3q16:
1631     case ARM::VLD3q32:
1632     case ARM::VLD3q8_UPD:
1633     case ARM::VLD3q16_UPD:
1634     case ARM::VLD3q32_UPD:
1635     case ARM::VLD4q8:
1636     case ARM::VLD4q16:
1637     case ARM::VLD4q32:
1638     case ARM::VLD4q8_UPD:
1639     case ARM::VLD4q16_UPD:
1640     case ARM::VLD4q32_UPD:
1641       CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder));
1642       break;
1643     default:
1644       break;
1645   }
1646 
1647   // Fourth output register
1648   switch (Inst.getOpcode()) {
1649     case ARM::VLD1d8Q:
1650     case ARM::VLD1d16Q:
1651     case ARM::VLD1d32Q:
1652     case ARM::VLD1d64Q:
1653     case ARM::VLD1d8Q_UPD:
1654     case ARM::VLD1d16Q_UPD:
1655     case ARM::VLD1d32Q_UPD:
1656     case ARM::VLD1d64Q_UPD:
1657     case ARM::VLD2q8:
1658     case ARM::VLD2q16:
1659     case ARM::VLD2q32:
1660     case ARM::VLD2q8_UPD:
1661     case ARM::VLD2q16_UPD:
1662     case ARM::VLD2q32_UPD:
1663     case ARM::VLD4d8:
1664     case ARM::VLD4d16:
1665     case ARM::VLD4d32:
1666     case ARM::VLD4d8_UPD:
1667     case ARM::VLD4d16_UPD:
1668     case ARM::VLD4d32_UPD:
1669       CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder));
1670       break;
1671     case ARM::VLD4q8:
1672     case ARM::VLD4q16:
1673     case ARM::VLD4q32:
1674     case ARM::VLD4q8_UPD:
1675     case ARM::VLD4q16_UPD:
1676     case ARM::VLD4q32_UPD:
1677       CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder));
1678       break;
1679     default:
1680       break;
1681   }
1682 
1683   // Writeback operand
1684   switch (Inst.getOpcode()) {
1685     case ARM::VLD1d8_UPD:
1686     case ARM::VLD1d16_UPD:
1687     case ARM::VLD1d32_UPD:
1688     case ARM::VLD1d64_UPD:
1689     case ARM::VLD1q8_UPD:
1690     case ARM::VLD1q16_UPD:
1691     case ARM::VLD1q32_UPD:
1692     case ARM::VLD1q64_UPD:
1693     case ARM::VLD1d8T_UPD:
1694     case ARM::VLD1d16T_UPD:
1695     case ARM::VLD1d32T_UPD:
1696     case ARM::VLD1d64T_UPD:
1697     case ARM::VLD1d8Q_UPD:
1698     case ARM::VLD1d16Q_UPD:
1699     case ARM::VLD1d32Q_UPD:
1700     case ARM::VLD1d64Q_UPD:
1701     case ARM::VLD2d8_UPD:
1702     case ARM::VLD2d16_UPD:
1703     case ARM::VLD2d32_UPD:
1704     case ARM::VLD2q8_UPD:
1705     case ARM::VLD2q16_UPD:
1706     case ARM::VLD2q32_UPD:
1707     case ARM::VLD2b8_UPD:
1708     case ARM::VLD2b16_UPD:
1709     case ARM::VLD2b32_UPD:
1710     case ARM::VLD3d8_UPD:
1711     case ARM::VLD3d16_UPD:
1712     case ARM::VLD3d32_UPD:
1713     case ARM::VLD3q8_UPD:
1714     case ARM::VLD3q16_UPD:
1715     case ARM::VLD3q32_UPD:
1716     case ARM::VLD4d8_UPD:
1717     case ARM::VLD4d16_UPD:
1718     case ARM::VLD4d32_UPD:
1719     case ARM::VLD4q8_UPD:
1720     case ARM::VLD4q16_UPD:
1721     case ARM::VLD4q32_UPD:
1722       CHECK(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder));
1723       break;
1724     default:
1725       break;
1726   }
1727 
1728   // AddrMode6 Base (register+alignment)
1729   CHECK(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder));
1730 
1731   // AddrMode6 Offset (register)
1732   if (Rm == 0xD)
1733     Inst.addOperand(MCOperand::CreateReg(0));
1734   else if (Rm != 0xF) {
1735     CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
1736   }
1737 
1738   return S;
1739 }
1740 
1741 static DecodeStatus DecodeVSTInstruction(llvm::MCInst &Inst, unsigned Insn,
1742                                  uint64_t Address, const void *Decoder) {
1743   DecodeStatus S = Success;
1744 
1745   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
1746   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
1747   unsigned wb = fieldFromInstruction32(Insn, 16, 4);
1748   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1749   Rn |= fieldFromInstruction32(Insn, 4, 2) << 4;
1750   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1751 
1752   // Writeback Operand
1753   switch (Inst.getOpcode()) {
1754     case ARM::VST1d8_UPD:
1755     case ARM::VST1d16_UPD:
1756     case ARM::VST1d32_UPD:
1757     case ARM::VST1d64_UPD:
1758     case ARM::VST1q8_UPD:
1759     case ARM::VST1q16_UPD:
1760     case ARM::VST1q32_UPD:
1761     case ARM::VST1q64_UPD:
1762     case ARM::VST1d8T_UPD:
1763     case ARM::VST1d16T_UPD:
1764     case ARM::VST1d32T_UPD:
1765     case ARM::VST1d64T_UPD:
1766     case ARM::VST1d8Q_UPD:
1767     case ARM::VST1d16Q_UPD:
1768     case ARM::VST1d32Q_UPD:
1769     case ARM::VST1d64Q_UPD:
1770     case ARM::VST2d8_UPD:
1771     case ARM::VST2d16_UPD:
1772     case ARM::VST2d32_UPD:
1773     case ARM::VST2q8_UPD:
1774     case ARM::VST2q16_UPD:
1775     case ARM::VST2q32_UPD:
1776     case ARM::VST2b8_UPD:
1777     case ARM::VST2b16_UPD:
1778     case ARM::VST2b32_UPD:
1779     case ARM::VST3d8_UPD:
1780     case ARM::VST3d16_UPD:
1781     case ARM::VST3d32_UPD:
1782     case ARM::VST3q8_UPD:
1783     case ARM::VST3q16_UPD:
1784     case ARM::VST3q32_UPD:
1785     case ARM::VST4d8_UPD:
1786     case ARM::VST4d16_UPD:
1787     case ARM::VST4d32_UPD:
1788     case ARM::VST4q8_UPD:
1789     case ARM::VST4q16_UPD:
1790     case ARM::VST4q32_UPD:
1791       CHECK(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder));
1792       break;
1793     default:
1794       break;
1795   }
1796 
1797   // AddrMode6 Base (register+alignment)
1798   CHECK(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder));
1799 
1800   // AddrMode6 Offset (register)
1801   if (Rm == 0xD)
1802     Inst.addOperand(MCOperand::CreateReg(0));
1803   else if (Rm != 0xF) {
1804     CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
1805   }
1806 
1807   // First input register
1808   CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
1809 
1810   // Second input register
1811   switch (Inst.getOpcode()) {
1812     case ARM::VST1q8:
1813     case ARM::VST1q16:
1814     case ARM::VST1q32:
1815     case ARM::VST1q64:
1816     case ARM::VST1q8_UPD:
1817     case ARM::VST1q16_UPD:
1818     case ARM::VST1q32_UPD:
1819     case ARM::VST1q64_UPD:
1820     case ARM::VST1d8T:
1821     case ARM::VST1d16T:
1822     case ARM::VST1d32T:
1823     case ARM::VST1d64T:
1824     case ARM::VST1d8T_UPD:
1825     case ARM::VST1d16T_UPD:
1826     case ARM::VST1d32T_UPD:
1827     case ARM::VST1d64T_UPD:
1828     case ARM::VST1d8Q:
1829     case ARM::VST1d16Q:
1830     case ARM::VST1d32Q:
1831     case ARM::VST1d64Q:
1832     case ARM::VST1d8Q_UPD:
1833     case ARM::VST1d16Q_UPD:
1834     case ARM::VST1d32Q_UPD:
1835     case ARM::VST1d64Q_UPD:
1836     case ARM::VST2d8:
1837     case ARM::VST2d16:
1838     case ARM::VST2d32:
1839     case ARM::VST2d8_UPD:
1840     case ARM::VST2d16_UPD:
1841     case ARM::VST2d32_UPD:
1842     case ARM::VST2q8:
1843     case ARM::VST2q16:
1844     case ARM::VST2q32:
1845     case ARM::VST2q8_UPD:
1846     case ARM::VST2q16_UPD:
1847     case ARM::VST2q32_UPD:
1848     case ARM::VST3d8:
1849     case ARM::VST3d16:
1850     case ARM::VST3d32:
1851     case ARM::VST3d8_UPD:
1852     case ARM::VST3d16_UPD:
1853     case ARM::VST3d32_UPD:
1854     case ARM::VST4d8:
1855     case ARM::VST4d16:
1856     case ARM::VST4d32:
1857     case ARM::VST4d8_UPD:
1858     case ARM::VST4d16_UPD:
1859     case ARM::VST4d32_UPD:
1860       CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder));
1861       break;
1862     case ARM::VST2b8:
1863     case ARM::VST2b16:
1864     case ARM::VST2b32:
1865     case ARM::VST2b8_UPD:
1866     case ARM::VST2b16_UPD:
1867     case ARM::VST2b32_UPD:
1868     case ARM::VST3q8:
1869     case ARM::VST3q16:
1870     case ARM::VST3q32:
1871     case ARM::VST3q8_UPD:
1872     case ARM::VST3q16_UPD:
1873     case ARM::VST3q32_UPD:
1874     case ARM::VST4q8:
1875     case ARM::VST4q16:
1876     case ARM::VST4q32:
1877     case ARM::VST4q8_UPD:
1878     case ARM::VST4q16_UPD:
1879     case ARM::VST4q32_UPD:
1880       CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder));
1881       break;
1882     default:
1883       break;
1884   }
1885 
1886   // Third input register
1887   switch (Inst.getOpcode()) {
1888     case ARM::VST1d8T:
1889     case ARM::VST1d16T:
1890     case ARM::VST1d32T:
1891     case ARM::VST1d64T:
1892     case ARM::VST1d8T_UPD:
1893     case ARM::VST1d16T_UPD:
1894     case ARM::VST1d32T_UPD:
1895     case ARM::VST1d64T_UPD:
1896     case ARM::VST1d8Q:
1897     case ARM::VST1d16Q:
1898     case ARM::VST1d32Q:
1899     case ARM::VST1d64Q:
1900     case ARM::VST1d8Q_UPD:
1901     case ARM::VST1d16Q_UPD:
1902     case ARM::VST1d32Q_UPD:
1903     case ARM::VST1d64Q_UPD:
1904     case ARM::VST2q8:
1905     case ARM::VST2q16:
1906     case ARM::VST2q32:
1907     case ARM::VST2q8_UPD:
1908     case ARM::VST2q16_UPD:
1909     case ARM::VST2q32_UPD:
1910     case ARM::VST3d8:
1911     case ARM::VST3d16:
1912     case ARM::VST3d32:
1913     case ARM::VST3d8_UPD:
1914     case ARM::VST3d16_UPD:
1915     case ARM::VST3d32_UPD:
1916     case ARM::VST4d8:
1917     case ARM::VST4d16:
1918     case ARM::VST4d32:
1919     case ARM::VST4d8_UPD:
1920     case ARM::VST4d16_UPD:
1921     case ARM::VST4d32_UPD:
1922       CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder));
1923       break;
1924     case ARM::VST3q8:
1925     case ARM::VST3q16:
1926     case ARM::VST3q32:
1927     case ARM::VST3q8_UPD:
1928     case ARM::VST3q16_UPD:
1929     case ARM::VST3q32_UPD:
1930     case ARM::VST4q8:
1931     case ARM::VST4q16:
1932     case ARM::VST4q32:
1933     case ARM::VST4q8_UPD:
1934     case ARM::VST4q16_UPD:
1935     case ARM::VST4q32_UPD:
1936       CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder));
1937       break;
1938     default:
1939       break;
1940   }
1941 
1942   // Fourth input register
1943   switch (Inst.getOpcode()) {
1944     case ARM::VST1d8Q:
1945     case ARM::VST1d16Q:
1946     case ARM::VST1d32Q:
1947     case ARM::VST1d64Q:
1948     case ARM::VST1d8Q_UPD:
1949     case ARM::VST1d16Q_UPD:
1950     case ARM::VST1d32Q_UPD:
1951     case ARM::VST1d64Q_UPD:
1952     case ARM::VST2q8:
1953     case ARM::VST2q16:
1954     case ARM::VST2q32:
1955     case ARM::VST2q8_UPD:
1956     case ARM::VST2q16_UPD:
1957     case ARM::VST2q32_UPD:
1958     case ARM::VST4d8:
1959     case ARM::VST4d16:
1960     case ARM::VST4d32:
1961     case ARM::VST4d8_UPD:
1962     case ARM::VST4d16_UPD:
1963     case ARM::VST4d32_UPD:
1964       CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder));
1965       break;
1966     case ARM::VST4q8:
1967     case ARM::VST4q16:
1968     case ARM::VST4q32:
1969     case ARM::VST4q8_UPD:
1970     case ARM::VST4q16_UPD:
1971     case ARM::VST4q32_UPD:
1972       CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder));
1973       break;
1974     default:
1975       break;
1976   }
1977 
1978   return S;
1979 }
1980 
1981 static DecodeStatus DecodeVLD1DupInstruction(llvm::MCInst &Inst, unsigned Insn,
1982                                     uint64_t Address, const void *Decoder) {
1983   DecodeStatus S = Success;
1984 
1985   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
1986   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
1987   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1988   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1989   unsigned align = fieldFromInstruction32(Insn, 4, 1);
1990   unsigned size = fieldFromInstruction32(Insn, 6, 2);
1991   unsigned regs = fieldFromInstruction32(Insn, 5, 1) + 1;
1992 
1993   align *= (1 << size);
1994 
1995   CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
1996   if (regs == 2) {
1997     CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder));
1998   }
1999   if (Rm != 0xF) {
2000     CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
2001   }
2002 
2003   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
2004   Inst.addOperand(MCOperand::CreateImm(align));
2005 
2006   if (Rm == 0xD)
2007     Inst.addOperand(MCOperand::CreateReg(0));
2008   else if (Rm != 0xF) {
2009     CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
2010   }
2011 
2012   return S;
2013 }
2014 
2015 static DecodeStatus DecodeVLD2DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2016                                     uint64_t Address, const void *Decoder) {
2017   DecodeStatus S = Success;
2018 
2019   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2020   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2021   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2022   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2023   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2024   unsigned size = 1 << fieldFromInstruction32(Insn, 6, 2);
2025   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2026   align *= 2*size;
2027 
2028   CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
2029   CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder));
2030   if (Rm != 0xF) {
2031     CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
2032   }
2033 
2034   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
2035   Inst.addOperand(MCOperand::CreateImm(align));
2036 
2037   if (Rm == 0xD)
2038     Inst.addOperand(MCOperand::CreateReg(0));
2039   else if (Rm != 0xF) {
2040     CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
2041   }
2042 
2043   return S;
2044 }
2045 
2046 static DecodeStatus DecodeVLD3DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2047                                     uint64_t Address, const void *Decoder) {
2048   DecodeStatus S = Success;
2049 
2050   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2051   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2052   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2053   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2054   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2055 
2056   CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
2057   CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder));
2058   CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder));
2059   if (Rm != 0xF) {
2060     CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
2061   }
2062 
2063   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
2064   Inst.addOperand(MCOperand::CreateImm(0));
2065 
2066   if (Rm == 0xD)
2067     Inst.addOperand(MCOperand::CreateReg(0));
2068   else if (Rm != 0xF) {
2069     CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
2070   }
2071 
2072   return S;
2073 }
2074 
2075 static DecodeStatus DecodeVLD4DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2076                                     uint64_t Address, const void *Decoder) {
2077   DecodeStatus S = Success;
2078 
2079   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2080   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2081   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2082   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2083   unsigned size = fieldFromInstruction32(Insn, 6, 2);
2084   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2085   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2086 
2087   if (size == 0x3) {
2088     size = 4;
2089     align = 16;
2090   } else {
2091     if (size == 2) {
2092       size = 1 << size;
2093       align *= 8;
2094     } else {
2095       size = 1 << size;
2096       align *= 4*size;
2097     }
2098   }
2099 
2100   CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
2101   CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder));
2102   CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder));
2103   CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+3*inc)%32, Address, Decoder));
2104   if (Rm != 0xF) {
2105     CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
2106   }
2107 
2108   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
2109   Inst.addOperand(MCOperand::CreateImm(align));
2110 
2111   if (Rm == 0xD)
2112     Inst.addOperand(MCOperand::CreateReg(0));
2113   else if (Rm != 0xF) {
2114     CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
2115   }
2116 
2117   return S;
2118 }
2119 
2120 static DecodeStatus
2121 DecodeNEONModImmInstruction(llvm::MCInst &Inst, unsigned Insn,
2122                             uint64_t Address, const void *Decoder) {
2123   DecodeStatus S = Success;
2124 
2125   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2126   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2127   unsigned imm = fieldFromInstruction32(Insn, 0, 4);
2128   imm |= fieldFromInstruction32(Insn, 16, 3) << 4;
2129   imm |= fieldFromInstruction32(Insn, 24, 1) << 7;
2130   imm |= fieldFromInstruction32(Insn, 8, 4) << 8;
2131   imm |= fieldFromInstruction32(Insn, 5, 1) << 12;
2132   unsigned Q = fieldFromInstruction32(Insn, 6, 1);
2133 
2134   if (Q) {
2135     CHECK(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder));
2136   } else {
2137     CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
2138   }
2139 
2140   Inst.addOperand(MCOperand::CreateImm(imm));
2141 
2142   switch (Inst.getOpcode()) {
2143     case ARM::VORRiv4i16:
2144     case ARM::VORRiv2i32:
2145     case ARM::VBICiv4i16:
2146     case ARM::VBICiv2i32:
2147       CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
2148       break;
2149     case ARM::VORRiv8i16:
2150     case ARM::VORRiv4i32:
2151     case ARM::VBICiv8i16:
2152     case ARM::VBICiv4i32:
2153       CHECK(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder));
2154       break;
2155     default:
2156       break;
2157   }
2158 
2159   return S;
2160 }
2161 
2162 static DecodeStatus DecodeVSHLMaxInstruction(llvm::MCInst &Inst, unsigned Insn,
2163                                         uint64_t Address, const void *Decoder) {
2164   DecodeStatus S = Success;
2165 
2166   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2167   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2168   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2169   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
2170   unsigned size = fieldFromInstruction32(Insn, 18, 2);
2171 
2172   CHECK(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder));
2173   CHECK(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder));
2174   Inst.addOperand(MCOperand::CreateImm(8 << size));
2175 
2176   return S;
2177 }
2178 
2179 static DecodeStatus DecodeShiftRight8Imm(llvm::MCInst &Inst, unsigned Val,
2180                                uint64_t Address, const void *Decoder) {
2181   Inst.addOperand(MCOperand::CreateImm(8 - Val));
2182   return Success;
2183 }
2184 
2185 static DecodeStatus DecodeShiftRight16Imm(llvm::MCInst &Inst, unsigned Val,
2186                                uint64_t Address, const void *Decoder) {
2187   Inst.addOperand(MCOperand::CreateImm(16 - Val));
2188   return Success;
2189 }
2190 
2191 static DecodeStatus DecodeShiftRight32Imm(llvm::MCInst &Inst, unsigned Val,
2192                                uint64_t Address, const void *Decoder) {
2193   Inst.addOperand(MCOperand::CreateImm(32 - Val));
2194   return Success;
2195 }
2196 
2197 static DecodeStatus DecodeShiftRight64Imm(llvm::MCInst &Inst, unsigned Val,
2198                                uint64_t Address, const void *Decoder) {
2199   Inst.addOperand(MCOperand::CreateImm(64 - Val));
2200   return Success;
2201 }
2202 
2203 static DecodeStatus DecodeTBLInstruction(llvm::MCInst &Inst, unsigned Insn,
2204                                uint64_t Address, const void *Decoder) {
2205   DecodeStatus S = Success;
2206 
2207   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2208   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2209   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2210   Rn |= fieldFromInstruction32(Insn, 7, 1) << 4;
2211   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2212   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
2213   unsigned op = fieldFromInstruction32(Insn, 6, 1);
2214   unsigned length = fieldFromInstruction32(Insn, 8, 2) + 1;
2215 
2216   CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
2217   if (op) {
2218     CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)); // Writeback
2219   }
2220 
2221   for (unsigned i = 0; i < length; ++i) {
2222     CHECK(S, DecodeDPRRegisterClass(Inst, (Rn+i)%32, Address, Decoder));
2223   }
2224 
2225   CHECK(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder));
2226 
2227   return S;
2228 }
2229 
2230 static DecodeStatus DecodeVFPfpImm(llvm::MCInst &Inst, unsigned Val,
2231                             uint64_t Address, const void *Decoder) {
2232   // The immediate needs to be a fully instantiated float.  However, the
2233   // auto-generated decoder is only able to fill in some of the bits
2234   // necessary.  For instance, the 'b' bit is replicated multiple times,
2235   // and is even present in inverted form in one bit.  We do a little
2236   // binary parsing here to fill in those missing bits, and then
2237   // reinterpret it all as a float.
2238   union {
2239     uint32_t integer;
2240     float fp;
2241   } fp_conv;
2242 
2243   fp_conv.integer = Val;
2244   uint32_t b = fieldFromInstruction32(Val, 25, 1);
2245   fp_conv.integer |= b << 26;
2246   fp_conv.integer |= b << 27;
2247   fp_conv.integer |= b << 28;
2248   fp_conv.integer |= b << 29;
2249   fp_conv.integer |= (~b & 0x1) << 30;
2250 
2251   Inst.addOperand(MCOperand::CreateFPImm(fp_conv.fp));
2252   return Success;
2253 }
2254 
2255 static DecodeStatus DecodeThumbAddSpecialReg(llvm::MCInst &Inst, uint16_t Insn,
2256                                      uint64_t Address, const void *Decoder) {
2257   DecodeStatus S = Success;
2258 
2259   unsigned dst = fieldFromInstruction16(Insn, 8, 3);
2260   unsigned imm = fieldFromInstruction16(Insn, 0, 8);
2261 
2262   CHECK(S, DecodetGPRRegisterClass(Inst, dst, Address, Decoder));
2263 
2264   if (Inst.getOpcode() == ARM::tADR)
2265     Inst.addOperand(MCOperand::CreateReg(ARM::PC));
2266   else if (Inst.getOpcode() == ARM::tADDrSPi)
2267     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2268   else
2269     return Fail;
2270 
2271   Inst.addOperand(MCOperand::CreateImm(imm));
2272   return S;
2273 }
2274 
2275 static DecodeStatus DecodeThumbBROperand(llvm::MCInst &Inst, unsigned Val,
2276                                  uint64_t Address, const void *Decoder) {
2277   Inst.addOperand(MCOperand::CreateImm(SignExtend32<12>(Val << 1)));
2278   return Success;
2279 }
2280 
2281 static DecodeStatus DecodeT2BROperand(llvm::MCInst &Inst, unsigned Val,
2282                                  uint64_t Address, const void *Decoder) {
2283   Inst.addOperand(MCOperand::CreateImm(SignExtend32<21>(Val)));
2284   return Success;
2285 }
2286 
2287 static DecodeStatus DecodeThumbCmpBROperand(llvm::MCInst &Inst, unsigned Val,
2288                                  uint64_t Address, const void *Decoder) {
2289   Inst.addOperand(MCOperand::CreateImm(SignExtend32<7>(Val << 1)));
2290   return Success;
2291 }
2292 
2293 static DecodeStatus DecodeThumbAddrModeRR(llvm::MCInst &Inst, unsigned Val,
2294                                  uint64_t Address, const void *Decoder) {
2295   DecodeStatus S = Success;
2296 
2297   unsigned Rn = fieldFromInstruction32(Val, 0, 3);
2298   unsigned Rm = fieldFromInstruction32(Val, 3, 3);
2299 
2300   CHECK(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder));
2301   CHECK(S, DecodetGPRRegisterClass(Inst, Rm, Address, Decoder));
2302 
2303   return S;
2304 }
2305 
2306 static DecodeStatus DecodeThumbAddrModeIS(llvm::MCInst &Inst, unsigned Val,
2307                                   uint64_t Address, const void *Decoder) {
2308   DecodeStatus S = Success;
2309 
2310   unsigned Rn = fieldFromInstruction32(Val, 0, 3);
2311   unsigned imm = fieldFromInstruction32(Val, 3, 5);
2312 
2313   CHECK(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder));
2314   Inst.addOperand(MCOperand::CreateImm(imm));
2315 
2316   return S;
2317 }
2318 
2319 static DecodeStatus DecodeThumbAddrModePC(llvm::MCInst &Inst, unsigned Val,
2320                                   uint64_t Address, const void *Decoder) {
2321   Inst.addOperand(MCOperand::CreateImm(Val << 2));
2322 
2323   return Success;
2324 }
2325 
2326 static DecodeStatus DecodeThumbAddrModeSP(llvm::MCInst &Inst, unsigned Val,
2327                                   uint64_t Address, const void *Decoder) {
2328   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2329   Inst.addOperand(MCOperand::CreateImm(Val));
2330 
2331   return Success;
2332 }
2333 
2334 static DecodeStatus DecodeT2AddrModeSOReg(llvm::MCInst &Inst, unsigned Val,
2335                                   uint64_t Address, const void *Decoder) {
2336   DecodeStatus S = Success;
2337 
2338   unsigned Rn = fieldFromInstruction32(Val, 6, 4);
2339   unsigned Rm = fieldFromInstruction32(Val, 2, 4);
2340   unsigned imm = fieldFromInstruction32(Val, 0, 2);
2341 
2342   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
2343   CHECK(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder));
2344   Inst.addOperand(MCOperand::CreateImm(imm));
2345 
2346   return S;
2347 }
2348 
2349 static DecodeStatus DecodeT2LoadShift(llvm::MCInst &Inst, unsigned Insn,
2350                               uint64_t Address, const void *Decoder) {
2351   DecodeStatus S = Success;
2352 
2353   if (Inst.getOpcode() != ARM::t2PLDs) {
2354     unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2355     CHECK(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder));
2356   }
2357 
2358   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2359   if (Rn == 0xF) {
2360     switch (Inst.getOpcode()) {
2361       case ARM::t2LDRBs:
2362         Inst.setOpcode(ARM::t2LDRBpci);
2363         break;
2364       case ARM::t2LDRHs:
2365         Inst.setOpcode(ARM::t2LDRHpci);
2366         break;
2367       case ARM::t2LDRSHs:
2368         Inst.setOpcode(ARM::t2LDRSHpci);
2369         break;
2370       case ARM::t2LDRSBs:
2371         Inst.setOpcode(ARM::t2LDRSBpci);
2372         break;
2373       case ARM::t2PLDs:
2374         Inst.setOpcode(ARM::t2PLDi12);
2375         Inst.addOperand(MCOperand::CreateReg(ARM::PC));
2376         break;
2377       default:
2378         return Fail;
2379     }
2380 
2381     int imm = fieldFromInstruction32(Insn, 0, 12);
2382     if (!fieldFromInstruction32(Insn, 23, 1)) imm *= -1;
2383     Inst.addOperand(MCOperand::CreateImm(imm));
2384 
2385     return S;
2386   }
2387 
2388   unsigned addrmode = fieldFromInstruction32(Insn, 4, 2);
2389   addrmode |= fieldFromInstruction32(Insn, 0, 4) << 2;
2390   addrmode |= fieldFromInstruction32(Insn, 16, 4) << 6;
2391   CHECK(S, DecodeT2AddrModeSOReg(Inst, addrmode, Address, Decoder));
2392 
2393   return S;
2394 }
2395 
2396 static DecodeStatus DecodeT2Imm8S4(llvm::MCInst &Inst, unsigned Val,
2397                            uint64_t Address, const void *Decoder) {
2398   int imm = Val & 0xFF;
2399   if (!(Val & 0x100)) imm *= -1;
2400   Inst.addOperand(MCOperand::CreateImm(imm << 2));
2401 
2402   return Success;
2403 }
2404 
2405 static DecodeStatus DecodeT2AddrModeImm8s4(llvm::MCInst &Inst, unsigned Val,
2406                                    uint64_t Address, const void *Decoder) {
2407   DecodeStatus S = Success;
2408 
2409   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
2410   unsigned imm = fieldFromInstruction32(Val, 0, 9);
2411 
2412   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
2413   CHECK(S, DecodeT2Imm8S4(Inst, imm, Address, Decoder));
2414 
2415   return S;
2416 }
2417 
2418 static DecodeStatus DecodeT2Imm8(llvm::MCInst &Inst, unsigned Val,
2419                          uint64_t Address, const void *Decoder) {
2420   int imm = Val & 0xFF;
2421   if (!(Val & 0x100)) imm *= -1;
2422   Inst.addOperand(MCOperand::CreateImm(imm));
2423 
2424   return Success;
2425 }
2426 
2427 
2428 static DecodeStatus DecodeT2AddrModeImm8(llvm::MCInst &Inst, unsigned Val,
2429                                  uint64_t Address, const void *Decoder) {
2430   DecodeStatus S = Success;
2431 
2432   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
2433   unsigned imm = fieldFromInstruction32(Val, 0, 9);
2434 
2435   // Some instructions always use an additive offset.
2436   switch (Inst.getOpcode()) {
2437     case ARM::t2LDRT:
2438     case ARM::t2LDRBT:
2439     case ARM::t2LDRHT:
2440     case ARM::t2LDRSBT:
2441     case ARM::t2LDRSHT:
2442       imm |= 0x100;
2443       break;
2444     default:
2445       break;
2446   }
2447 
2448   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
2449   CHECK(S, DecodeT2Imm8(Inst, imm, Address, Decoder));
2450 
2451   return S;
2452 }
2453 
2454 
2455 static DecodeStatus DecodeT2AddrModeImm12(llvm::MCInst &Inst, unsigned Val,
2456                                   uint64_t Address, const void *Decoder) {
2457   DecodeStatus S = Success;
2458 
2459   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
2460   unsigned imm = fieldFromInstruction32(Val, 0, 12);
2461 
2462   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
2463   Inst.addOperand(MCOperand::CreateImm(imm));
2464 
2465   return S;
2466 }
2467 
2468 
2469 static DecodeStatus DecodeThumbAddSPImm(llvm::MCInst &Inst, uint16_t Insn,
2470                                 uint64_t Address, const void *Decoder) {
2471   unsigned imm = fieldFromInstruction16(Insn, 0, 7);
2472 
2473   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2474   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2475   Inst.addOperand(MCOperand::CreateImm(imm));
2476 
2477   return Success;
2478 }
2479 
2480 static DecodeStatus DecodeThumbAddSPReg(llvm::MCInst &Inst, uint16_t Insn,
2481                                 uint64_t Address, const void *Decoder) {
2482   DecodeStatus S = Success;
2483 
2484   if (Inst.getOpcode() == ARM::tADDrSP) {
2485     unsigned Rdm = fieldFromInstruction16(Insn, 0, 3);
2486     Rdm |= fieldFromInstruction16(Insn, 7, 1) << 3;
2487 
2488     CHECK(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder));
2489     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2490     CHECK(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder));
2491   } else if (Inst.getOpcode() == ARM::tADDspr) {
2492     unsigned Rm = fieldFromInstruction16(Insn, 3, 4);
2493 
2494     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2495     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2496     CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
2497   }
2498 
2499   return S;
2500 }
2501 
2502 static DecodeStatus DecodeThumbCPS(llvm::MCInst &Inst, uint16_t Insn,
2503                            uint64_t Address, const void *Decoder) {
2504   unsigned imod = fieldFromInstruction16(Insn, 4, 1) | 0x2;
2505   unsigned flags = fieldFromInstruction16(Insn, 0, 3);
2506 
2507   Inst.addOperand(MCOperand::CreateImm(imod));
2508   Inst.addOperand(MCOperand::CreateImm(flags));
2509 
2510   return Success;
2511 }
2512 
2513 static DecodeStatus DecodePostIdxReg(llvm::MCInst &Inst, unsigned Insn,
2514                              uint64_t Address, const void *Decoder) {
2515   DecodeStatus S = Success;
2516   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2517   unsigned add = fieldFromInstruction32(Insn, 4, 1);
2518 
2519   CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)) ;
2520   Inst.addOperand(MCOperand::CreateImm(add));
2521 
2522   return S;
2523 }
2524 
2525 static DecodeStatus DecodeThumbBLXOffset(llvm::MCInst &Inst, unsigned Val,
2526                                  uint64_t Address, const void *Decoder) {
2527   Inst.addOperand(MCOperand::CreateImm(SignExtend32<22>(Val << 1)));
2528   return Success;
2529 }
2530 
2531 static DecodeStatus DecodeCoprocessor(llvm::MCInst &Inst, unsigned Val,
2532                               uint64_t Address, const void *Decoder) {
2533   if (Val == 0xA || Val == 0xB)
2534     return Fail;
2535 
2536   Inst.addOperand(MCOperand::CreateImm(Val));
2537   return Success;
2538 }
2539 
2540 static DecodeStatus
2541 DecodeThumb2BCCInstruction(llvm::MCInst &Inst, unsigned Insn,
2542                            uint64_t Address, const void *Decoder) {
2543   DecodeStatus S = Success;
2544 
2545   unsigned pred = fieldFromInstruction32(Insn, 22, 4);
2546   if (pred == 0xE || pred == 0xF) {
2547     unsigned opc = fieldFromInstruction32(Insn, 4, 2);
2548     switch (opc) {
2549       default:
2550         return Fail;
2551       case 0:
2552         Inst.setOpcode(ARM::t2DSB);
2553         break;
2554       case 1:
2555         Inst.setOpcode(ARM::t2DMB);
2556         break;
2557       case 2:
2558         Inst.setOpcode(ARM::t2ISB);
2559         return Success;
2560     }
2561 
2562     unsigned imm = fieldFromInstruction32(Insn, 0, 4);
2563     return DecodeMemBarrierOption(Inst, imm, Address, Decoder);
2564   }
2565 
2566   unsigned brtarget = fieldFromInstruction32(Insn, 0, 11) << 1;
2567   brtarget |= fieldFromInstruction32(Insn, 11, 1) << 19;
2568   brtarget |= fieldFromInstruction32(Insn, 13, 1) << 18;
2569   brtarget |= fieldFromInstruction32(Insn, 16, 6) << 12;
2570   brtarget |= fieldFromInstruction32(Insn, 26, 1) << 20;
2571 
2572   CHECK(S, DecodeT2BROperand(Inst, brtarget, Address, Decoder));
2573   CHECK(S, DecodePredicateOperand(Inst, pred, Address, Decoder));
2574 
2575   return S;
2576 }
2577 
2578 // Decode a shifted immediate operand.  These basically consist
2579 // of an 8-bit value, and a 4-bit directive that specifies either
2580 // a splat operation or a rotation.
2581 static DecodeStatus DecodeT2SOImm(llvm::MCInst &Inst, unsigned Val,
2582                           uint64_t Address, const void *Decoder) {
2583   unsigned ctrl = fieldFromInstruction32(Val, 10, 2);
2584   if (ctrl == 0) {
2585     unsigned byte = fieldFromInstruction32(Val, 8, 2);
2586     unsigned imm = fieldFromInstruction32(Val, 0, 8);
2587     switch (byte) {
2588       case 0:
2589         Inst.addOperand(MCOperand::CreateImm(imm));
2590         break;
2591       case 1:
2592         Inst.addOperand(MCOperand::CreateImm((imm << 16) | imm));
2593         break;
2594       case 2:
2595         Inst.addOperand(MCOperand::CreateImm((imm << 24) | (imm << 8)));
2596         break;
2597       case 3:
2598         Inst.addOperand(MCOperand::CreateImm((imm << 24) | (imm << 16) |
2599                                              (imm << 8)  |  imm));
2600         break;
2601     }
2602   } else {
2603     unsigned unrot = fieldFromInstruction32(Val, 0, 7) | 0x80;
2604     unsigned rot = fieldFromInstruction32(Val, 7, 5);
2605     unsigned imm = (unrot >> rot) | (unrot << ((32-rot)&31));
2606     Inst.addOperand(MCOperand::CreateImm(imm));
2607   }
2608 
2609   return Success;
2610 }
2611 
2612 static DecodeStatus
2613 DecodeThumbBCCTargetOperand(llvm::MCInst &Inst, unsigned Val,
2614                             uint64_t Address, const void *Decoder){
2615   Inst.addOperand(MCOperand::CreateImm(Val << 1));
2616   return Success;
2617 }
2618 
2619 static DecodeStatus DecodeThumbBLTargetOperand(llvm::MCInst &Inst, unsigned Val,
2620                                        uint64_t Address, const void *Decoder){
2621   Inst.addOperand(MCOperand::CreateImm(SignExtend32<22>(Val << 1)));
2622   return Success;
2623 }
2624 
2625 static DecodeStatus DecodeMemBarrierOption(llvm::MCInst &Inst, unsigned Val,
2626                                    uint64_t Address, const void *Decoder) {
2627   switch (Val) {
2628   default:
2629     return Fail;
2630   case 0xF: // SY
2631   case 0xE: // ST
2632   case 0xB: // ISH
2633   case 0xA: // ISHST
2634   case 0x7: // NSH
2635   case 0x6: // NSHST
2636   case 0x3: // OSH
2637   case 0x2: // OSHST
2638     break;
2639   }
2640 
2641   Inst.addOperand(MCOperand::CreateImm(Val));
2642   return Success;
2643 }
2644 
2645 static DecodeStatus DecodeMSRMask(llvm::MCInst &Inst, unsigned Val,
2646                           uint64_t Address, const void *Decoder) {
2647   if (!Val) return Fail;
2648   Inst.addOperand(MCOperand::CreateImm(Val));
2649   return Success;
2650 }
2651 
2652 static DecodeStatus DecodeDoubleRegLoad(llvm::MCInst &Inst, unsigned Insn,
2653                                         uint64_t Address, const void *Decoder) {
2654   DecodeStatus S = Success;
2655 
2656   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2657   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2658   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
2659 
2660   if ((Rt & 1) || Rt == 0xE || Rn == 0xF) return Fail;
2661 
2662   CHECK(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder));
2663   CHECK(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder));
2664   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
2665   CHECK(S, DecodePredicateOperand(Inst, pred, Address, Decoder));
2666 
2667   return S;
2668 }
2669 
2670 
2671 static DecodeStatus DecodeDoubleRegStore(llvm::MCInst &Inst, unsigned Insn,
2672                                          uint64_t Address, const void *Decoder){
2673   DecodeStatus S = Success;
2674 
2675   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2676   unsigned Rt = fieldFromInstruction32(Insn, 0, 4);
2677   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2678   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
2679 
2680   CHECK(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder));
2681 
2682   if ((Rt & 1) || Rt == 0xE || Rn == 0xF) return Fail;
2683   if (Rd == Rn || Rd == Rt || Rd == Rt+1) return Fail;
2684 
2685   CHECK(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder));
2686   CHECK(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder));
2687   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
2688   CHECK(S, DecodePredicateOperand(Inst, pred, Address, Decoder));
2689 
2690   return S;
2691 }
2692 
2693 static DecodeStatus DecodeSTRPreImm(llvm::MCInst &Inst, unsigned Insn,
2694                             uint64_t Address, const void *Decoder) {
2695   DecodeStatus S = Success;
2696 
2697   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2698   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2699   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
2700   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
2701   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
2702   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
2703 
2704   if (Rn == 0xF || Rn == Rt) CHECK(S, Unpredictable);
2705 
2706   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
2707   CHECK(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder));
2708   CHECK(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder));
2709   CHECK(S, DecodePredicateOperand(Inst, pred, Address, Decoder));
2710 
2711   return S;
2712 }
2713 
2714 static DecodeStatus DecodeSTRPreReg(llvm::MCInst &Inst, unsigned Insn,
2715                             uint64_t Address, const void *Decoder) {
2716   DecodeStatus S = Success;
2717 
2718   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2719   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2720   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
2721   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
2722   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
2723   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
2724 
2725   if (Rn == 0xF || Rn == Rt) CHECK(S, Unpredictable);
2726 
2727   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
2728   CHECK(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder));
2729   CHECK(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder));
2730   CHECK(S, DecodePredicateOperand(Inst, pred, Address, Decoder));
2731 
2732   return S;
2733 }
2734 
2735 static DecodeStatus DecodeVLD1LN(llvm::MCInst &Inst, unsigned Insn,
2736                          uint64_t Address, const void *Decoder) {
2737   DecodeStatus S = Success;
2738 
2739   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2740   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2741   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2742   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2743   unsigned size = fieldFromInstruction32(Insn, 10, 2);
2744 
2745   unsigned align = 0;
2746   unsigned index = 0;
2747   switch (size) {
2748     default:
2749       return Fail;
2750     case 0:
2751       if (fieldFromInstruction32(Insn, 4, 1))
2752         return Fail; // UNDEFINED
2753       index = fieldFromInstruction32(Insn, 5, 3);
2754       break;
2755     case 1:
2756       if (fieldFromInstruction32(Insn, 5, 1))
2757         return Fail; // UNDEFINED
2758       index = fieldFromInstruction32(Insn, 6, 2);
2759       if (fieldFromInstruction32(Insn, 4, 1))
2760         align = 2;
2761       break;
2762     case 2:
2763       if (fieldFromInstruction32(Insn, 6, 1))
2764         return Fail; // UNDEFINED
2765       index = fieldFromInstruction32(Insn, 7, 1);
2766       if (fieldFromInstruction32(Insn, 4, 2) != 0)
2767         align = 4;
2768   }
2769 
2770   CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
2771   if (Rm != 0xF) { // Writeback
2772     CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
2773   }
2774   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
2775   Inst.addOperand(MCOperand::CreateImm(align));
2776   if (Rm != 0xF) {
2777     if (Rm != 0xD)
2778       CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
2779     else
2780       Inst.addOperand(MCOperand::CreateReg(0));
2781   }
2782 
2783   CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
2784   Inst.addOperand(MCOperand::CreateImm(index));
2785 
2786   return S;
2787 }
2788 
2789 static DecodeStatus DecodeVST1LN(llvm::MCInst &Inst, unsigned Insn,
2790                          uint64_t Address, const void *Decoder) {
2791   DecodeStatus S = Success;
2792 
2793   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2794   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2795   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2796   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2797   unsigned size = fieldFromInstruction32(Insn, 10, 2);
2798 
2799   unsigned align = 0;
2800   unsigned index = 0;
2801   switch (size) {
2802     default:
2803       return Fail;
2804     case 0:
2805       if (fieldFromInstruction32(Insn, 4, 1))
2806         return Fail; // UNDEFINED
2807       index = fieldFromInstruction32(Insn, 5, 3);
2808       break;
2809     case 1:
2810       if (fieldFromInstruction32(Insn, 5, 1))
2811         return Fail; // UNDEFINED
2812       index = fieldFromInstruction32(Insn, 6, 2);
2813       if (fieldFromInstruction32(Insn, 4, 1))
2814         align = 2;
2815       break;
2816     case 2:
2817       if (fieldFromInstruction32(Insn, 6, 1))
2818         return Fail; // UNDEFINED
2819       index = fieldFromInstruction32(Insn, 7, 1);
2820       if (fieldFromInstruction32(Insn, 4, 2) != 0)
2821         align = 4;
2822   }
2823 
2824   if (Rm != 0xF) { // Writeback
2825     CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
2826   }
2827   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
2828   Inst.addOperand(MCOperand::CreateImm(align));
2829   if (Rm != 0xF) {
2830     if (Rm != 0xD)
2831       CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
2832     else
2833       Inst.addOperand(MCOperand::CreateReg(0));
2834   }
2835 
2836   CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
2837   Inst.addOperand(MCOperand::CreateImm(index));
2838 
2839   return S;
2840 }
2841 
2842 
2843 static DecodeStatus DecodeVLD2LN(llvm::MCInst &Inst, unsigned Insn,
2844                          uint64_t Address, const void *Decoder) {
2845   DecodeStatus S = Success;
2846 
2847   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2848   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2849   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2850   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2851   unsigned size = fieldFromInstruction32(Insn, 10, 2);
2852 
2853   unsigned align = 0;
2854   unsigned index = 0;
2855   unsigned inc = 1;
2856   switch (size) {
2857     default:
2858       return Fail;
2859     case 0:
2860       index = fieldFromInstruction32(Insn, 5, 3);
2861       if (fieldFromInstruction32(Insn, 4, 1))
2862         align = 2;
2863       break;
2864     case 1:
2865       index = fieldFromInstruction32(Insn, 6, 2);
2866       if (fieldFromInstruction32(Insn, 4, 1))
2867         align = 4;
2868       if (fieldFromInstruction32(Insn, 5, 1))
2869         inc = 2;
2870       break;
2871     case 2:
2872       if (fieldFromInstruction32(Insn, 5, 1))
2873         return Fail; // UNDEFINED
2874       index = fieldFromInstruction32(Insn, 7, 1);
2875       if (fieldFromInstruction32(Insn, 4, 1) != 0)
2876         align = 8;
2877       if (fieldFromInstruction32(Insn, 6, 1))
2878         inc = 2;
2879       break;
2880   }
2881 
2882   CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
2883   CHECK(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder));
2884   if (Rm != 0xF) { // Writeback
2885     CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
2886   }
2887   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
2888   Inst.addOperand(MCOperand::CreateImm(align));
2889   if (Rm != 0xF) {
2890     if (Rm != 0xD)
2891       CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
2892     else
2893       Inst.addOperand(MCOperand::CreateReg(0));
2894   }
2895 
2896   CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
2897   CHECK(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder));
2898   Inst.addOperand(MCOperand::CreateImm(index));
2899 
2900   return S;
2901 }
2902 
2903 static DecodeStatus DecodeVST2LN(llvm::MCInst &Inst, unsigned Insn,
2904                          uint64_t Address, const void *Decoder) {
2905   DecodeStatus S = Success;
2906 
2907   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2908   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2909   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2910   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2911   unsigned size = fieldFromInstruction32(Insn, 10, 2);
2912 
2913   unsigned align = 0;
2914   unsigned index = 0;
2915   unsigned inc = 1;
2916   switch (size) {
2917     default:
2918       return Fail;
2919     case 0:
2920       index = fieldFromInstruction32(Insn, 5, 3);
2921       if (fieldFromInstruction32(Insn, 4, 1))
2922         align = 2;
2923       break;
2924     case 1:
2925       index = fieldFromInstruction32(Insn, 6, 2);
2926       if (fieldFromInstruction32(Insn, 4, 1))
2927         align = 4;
2928       if (fieldFromInstruction32(Insn, 5, 1))
2929         inc = 2;
2930       break;
2931     case 2:
2932       if (fieldFromInstruction32(Insn, 5, 1))
2933         return Fail; // UNDEFINED
2934       index = fieldFromInstruction32(Insn, 7, 1);
2935       if (fieldFromInstruction32(Insn, 4, 1) != 0)
2936         align = 8;
2937       if (fieldFromInstruction32(Insn, 6, 1))
2938         inc = 2;
2939       break;
2940   }
2941 
2942   if (Rm != 0xF) { // Writeback
2943     CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
2944   }
2945   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
2946   Inst.addOperand(MCOperand::CreateImm(align));
2947   if (Rm != 0xF) {
2948     if (Rm != 0xD)
2949       CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
2950     else
2951       Inst.addOperand(MCOperand::CreateReg(0));
2952   }
2953 
2954   CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
2955   CHECK(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder));
2956   Inst.addOperand(MCOperand::CreateImm(index));
2957 
2958   return S;
2959 }
2960 
2961 
2962 static DecodeStatus DecodeVLD3LN(llvm::MCInst &Inst, unsigned Insn,
2963                          uint64_t Address, const void *Decoder) {
2964   DecodeStatus S = Success;
2965 
2966   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2967   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2968   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2969   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2970   unsigned size = fieldFromInstruction32(Insn, 10, 2);
2971 
2972   unsigned align = 0;
2973   unsigned index = 0;
2974   unsigned inc = 1;
2975   switch (size) {
2976     default:
2977       return Fail;
2978     case 0:
2979       if (fieldFromInstruction32(Insn, 4, 1))
2980         return Fail; // UNDEFINED
2981       index = fieldFromInstruction32(Insn, 5, 3);
2982       break;
2983     case 1:
2984       if (fieldFromInstruction32(Insn, 4, 1))
2985         return Fail; // UNDEFINED
2986       index = fieldFromInstruction32(Insn, 6, 2);
2987       if (fieldFromInstruction32(Insn, 5, 1))
2988         inc = 2;
2989       break;
2990     case 2:
2991       if (fieldFromInstruction32(Insn, 4, 2))
2992         return Fail; // UNDEFINED
2993       index = fieldFromInstruction32(Insn, 7, 1);
2994       if (fieldFromInstruction32(Insn, 6, 1))
2995         inc = 2;
2996       break;
2997   }
2998 
2999   CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
3000   CHECK(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder));
3001   CHECK(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder));
3002 
3003   if (Rm != 0xF) { // Writeback
3004     CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
3005   }
3006   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
3007   Inst.addOperand(MCOperand::CreateImm(align));
3008   if (Rm != 0xF) {
3009     if (Rm != 0xD)
3010       CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
3011     else
3012       Inst.addOperand(MCOperand::CreateReg(0));
3013   }
3014 
3015   CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
3016   CHECK(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder));
3017   CHECK(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder));
3018   Inst.addOperand(MCOperand::CreateImm(index));
3019 
3020   return S;
3021 }
3022 
3023 static DecodeStatus DecodeVST3LN(llvm::MCInst &Inst, unsigned Insn,
3024                          uint64_t Address, const void *Decoder) {
3025   DecodeStatus S = Success;
3026 
3027   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3028   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3029   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3030   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3031   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3032 
3033   unsigned align = 0;
3034   unsigned index = 0;
3035   unsigned inc = 1;
3036   switch (size) {
3037     default:
3038       return Fail;
3039     case 0:
3040       if (fieldFromInstruction32(Insn, 4, 1))
3041         return Fail; // UNDEFINED
3042       index = fieldFromInstruction32(Insn, 5, 3);
3043       break;
3044     case 1:
3045       if (fieldFromInstruction32(Insn, 4, 1))
3046         return Fail; // UNDEFINED
3047       index = fieldFromInstruction32(Insn, 6, 2);
3048       if (fieldFromInstruction32(Insn, 5, 1))
3049         inc = 2;
3050       break;
3051     case 2:
3052       if (fieldFromInstruction32(Insn, 4, 2))
3053         return Fail; // UNDEFINED
3054       index = fieldFromInstruction32(Insn, 7, 1);
3055       if (fieldFromInstruction32(Insn, 6, 1))
3056         inc = 2;
3057       break;
3058   }
3059 
3060   if (Rm != 0xF) { // Writeback
3061     CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
3062   }
3063   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
3064   Inst.addOperand(MCOperand::CreateImm(align));
3065   if (Rm != 0xF) {
3066     if (Rm != 0xD)
3067       CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
3068     else
3069       Inst.addOperand(MCOperand::CreateReg(0));
3070   }
3071 
3072   CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
3073   CHECK(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder));
3074   CHECK(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder));
3075   Inst.addOperand(MCOperand::CreateImm(index));
3076 
3077   return S;
3078 }
3079 
3080 
3081 static DecodeStatus DecodeVLD4LN(llvm::MCInst &Inst, unsigned Insn,
3082                          uint64_t Address, const void *Decoder) {
3083   DecodeStatus S = Success;
3084 
3085   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3086   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3087   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3088   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3089   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3090 
3091   unsigned align = 0;
3092   unsigned index = 0;
3093   unsigned inc = 1;
3094   switch (size) {
3095     default:
3096       return Fail;
3097     case 0:
3098       if (fieldFromInstruction32(Insn, 4, 1))
3099         align = 4;
3100       index = fieldFromInstruction32(Insn, 5, 3);
3101       break;
3102     case 1:
3103       if (fieldFromInstruction32(Insn, 4, 1))
3104         align = 8;
3105       index = fieldFromInstruction32(Insn, 6, 2);
3106       if (fieldFromInstruction32(Insn, 5, 1))
3107         inc = 2;
3108       break;
3109     case 2:
3110       if (fieldFromInstruction32(Insn, 4, 2))
3111         align = 4 << fieldFromInstruction32(Insn, 4, 2);
3112       index = fieldFromInstruction32(Insn, 7, 1);
3113       if (fieldFromInstruction32(Insn, 6, 1))
3114         inc = 2;
3115       break;
3116   }
3117 
3118   CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
3119   CHECK(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder));
3120   CHECK(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder));
3121   CHECK(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder));
3122 
3123   if (Rm != 0xF) { // Writeback
3124     CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
3125   }
3126   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
3127   Inst.addOperand(MCOperand::CreateImm(align));
3128   if (Rm != 0xF) {
3129     if (Rm != 0xD)
3130       CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
3131     else
3132       Inst.addOperand(MCOperand::CreateReg(0));
3133   }
3134 
3135   CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
3136   CHECK(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder));
3137   CHECK(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder));
3138   CHECK(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder));
3139   Inst.addOperand(MCOperand::CreateImm(index));
3140 
3141   return S;
3142 }
3143 
3144 static DecodeStatus DecodeVST4LN(llvm::MCInst &Inst, unsigned Insn,
3145                          uint64_t Address, const void *Decoder) {
3146   DecodeStatus S = Success;
3147 
3148   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3149   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3150   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3151   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3152   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3153 
3154   unsigned align = 0;
3155   unsigned index = 0;
3156   unsigned inc = 1;
3157   switch (size) {
3158     default:
3159       return Fail;
3160     case 0:
3161       if (fieldFromInstruction32(Insn, 4, 1))
3162         align = 4;
3163       index = fieldFromInstruction32(Insn, 5, 3);
3164       break;
3165     case 1:
3166       if (fieldFromInstruction32(Insn, 4, 1))
3167         align = 8;
3168       index = fieldFromInstruction32(Insn, 6, 2);
3169       if (fieldFromInstruction32(Insn, 5, 1))
3170         inc = 2;
3171       break;
3172     case 2:
3173       if (fieldFromInstruction32(Insn, 4, 2))
3174         align = 4 << fieldFromInstruction32(Insn, 4, 2);
3175       index = fieldFromInstruction32(Insn, 7, 1);
3176       if (fieldFromInstruction32(Insn, 6, 1))
3177         inc = 2;
3178       break;
3179   }
3180 
3181   if (Rm != 0xF) { // Writeback
3182     CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
3183   }
3184   CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
3185   Inst.addOperand(MCOperand::CreateImm(align));
3186   if (Rm != 0xF) {
3187     if (Rm != 0xD)
3188       CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
3189     else
3190       Inst.addOperand(MCOperand::CreateReg(0));
3191   }
3192 
3193   CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
3194   CHECK(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder));
3195   CHECK(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder));
3196   CHECK(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder));
3197   Inst.addOperand(MCOperand::CreateImm(index));
3198 
3199   return S;
3200 }
3201 
3202 static DecodeStatus DecodeVMOVSRR(llvm::MCInst &Inst, unsigned Insn,
3203                                   uint64_t Address, const void *Decoder) {
3204   DecodeStatus S = Success;
3205   unsigned Rt  = fieldFromInstruction32(Insn, 12, 4);
3206   unsigned Rt2 = fieldFromInstruction32(Insn, 16, 4);
3207   unsigned Rm  = fieldFromInstruction32(Insn,  0, 4);
3208   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3209   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
3210 
3211   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
3212     CHECK(S, Unpredictable);
3213 
3214   CHECK(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder));
3215   CHECK(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder));
3216   CHECK(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder));
3217   CHECK(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder));
3218   CHECK(S, DecodePredicateOperand(Inst, pred, Address, Decoder));
3219 
3220   return S;
3221 }
3222 
3223 static DecodeStatus DecodeVMOVRRS(llvm::MCInst &Inst, unsigned Insn,
3224                                   uint64_t Address, const void *Decoder) {
3225   DecodeStatus S = Success;
3226   unsigned Rt  = fieldFromInstruction32(Insn, 12, 4);
3227   unsigned Rt2 = fieldFromInstruction32(Insn, 16, 4);
3228   unsigned Rm  = fieldFromInstruction32(Insn,  0, 4);
3229   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3230   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
3231 
3232   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
3233     CHECK(S, Unpredictable);
3234 
3235   CHECK(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder));
3236   CHECK(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder));
3237   CHECK(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder));
3238   CHECK(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder));
3239   CHECK(S, DecodePredicateOperand(Inst, pred, Address, Decoder));
3240 
3241   return S;
3242 }
3243