xref: /llvm-project/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp (revision db4ce60328e1a05fcc0d40549009cb0ba2860298)
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/Support/Debug.h"
22 #include "llvm/Support/MemoryObject.h"
23 #include "llvm/Support/ErrorHandling.h"
24 #include "llvm/Support/TargetRegistry.h"
25 #include "llvm/Support/raw_ostream.h"
26 
27 using namespace llvm;
28 
29 static bool Check(MCDisassembler::DecodeStatus &Out, MCDisassembler::DecodeStatus In) {
30   switch (In) {
31     case MCDisassembler::Success:
32       // Out stays the same.
33       return true;
34     case MCDisassembler::SoftFail:
35       Out = In;
36       return true;
37     case MCDisassembler::Fail:
38       Out = In;
39       return false;
40   }
41   return false;
42 }
43 
44 // Forward declare these because the autogenerated code will reference them.
45 // Definitions are further down.
46 static MCDisassembler::DecodeStatus DecodeGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
47                                    uint64_t Address, const void *Decoder);
48 static MCDisassembler::DecodeStatus DecodeGPRnopcRegisterClass(llvm::MCInst &Inst,
49                                                unsigned RegNo, uint64_t Address,
50                                                const void *Decoder);
51 static MCDisassembler::DecodeStatus DecodetGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
52                                    uint64_t Address, const void *Decoder);
53 static MCDisassembler::DecodeStatus DecodetcGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
54                                    uint64_t Address, const void *Decoder);
55 static MCDisassembler::DecodeStatus DecoderGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
56                                    uint64_t Address, const void *Decoder);
57 static MCDisassembler::DecodeStatus DecodeSPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
58                                    uint64_t Address, const void *Decoder);
59 static MCDisassembler::DecodeStatus DecodeDPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
60                                    uint64_t Address, const void *Decoder);
61 static MCDisassembler::DecodeStatus DecodeDPR_8RegisterClass(llvm::MCInst &Inst, unsigned RegNo,
62                                    uint64_t Address, const void *Decoder);
63 static MCDisassembler::DecodeStatus DecodeDPR_VFP2RegisterClass(llvm::MCInst &Inst,
64                                                 unsigned RegNo,
65                                                 uint64_t Address,
66                                                 const void *Decoder);
67 static MCDisassembler::DecodeStatus DecodeQPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
68                                    uint64_t Address, const void *Decoder);
69 
70 static MCDisassembler::DecodeStatus DecodePredicateOperand(llvm::MCInst &Inst, unsigned Val,
71                                uint64_t Address, const void *Decoder);
72 static MCDisassembler::DecodeStatus DecodeCCOutOperand(llvm::MCInst &Inst, unsigned Val,
73                                uint64_t Address, const void *Decoder);
74 static MCDisassembler::DecodeStatus DecodeSOImmOperand(llvm::MCInst &Inst, unsigned Val,
75                                uint64_t Address, const void *Decoder);
76 static MCDisassembler::DecodeStatus DecodeRegListOperand(llvm::MCInst &Inst, unsigned Val,
77                                uint64_t Address, const void *Decoder);
78 static MCDisassembler::DecodeStatus DecodeSPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
79                                uint64_t Address, const void *Decoder);
80 static MCDisassembler::DecodeStatus DecodeDPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
81                                uint64_t Address, const void *Decoder);
82 
83 static MCDisassembler::DecodeStatus DecodeBitfieldMaskOperand(llvm::MCInst &Inst, unsigned Insn,
84                                uint64_t Address, const void *Decoder);
85 static MCDisassembler::DecodeStatus DecodeCopMemInstruction(llvm::MCInst &Inst, unsigned Insn,
86                                uint64_t Address, const void *Decoder);
87 static MCDisassembler::DecodeStatus DecodeAddrMode2IdxInstruction(llvm::MCInst &Inst,
88                                                   unsigned Insn,
89                                                   uint64_t Address,
90                                                   const void *Decoder);
91 static MCDisassembler::DecodeStatus DecodeSORegMemOperand(llvm::MCInst &Inst, unsigned Insn,
92                                uint64_t Address, const void *Decoder);
93 static MCDisassembler::DecodeStatus DecodeAddrMode3Instruction(llvm::MCInst &Inst,unsigned Insn,
94                                uint64_t Address, const void *Decoder);
95 static MCDisassembler::DecodeStatus DecodeSORegImmOperand(llvm::MCInst &Inst, unsigned Insn,
96                                uint64_t Address, const void *Decoder);
97 static MCDisassembler::DecodeStatus DecodeSORegRegOperand(llvm::MCInst &Inst, unsigned Insn,
98                                uint64_t Address, const void *Decoder);
99 
100 static MCDisassembler::DecodeStatus DecodeMemMultipleWritebackInstruction(llvm::MCInst & Inst,
101                                                   unsigned Insn,
102                                                   uint64_t Adddress,
103                                                   const void *Decoder);
104 static MCDisassembler::DecodeStatus DecodeSMLAInstruction(llvm::MCInst &Inst, unsigned Insn,
105                                uint64_t Address, const void *Decoder);
106 static MCDisassembler::DecodeStatus DecodeCPSInstruction(llvm::MCInst &Inst, unsigned Insn,
107                                uint64_t Address, const void *Decoder);
108 static MCDisassembler::DecodeStatus DecodeT2CPSInstruction(llvm::MCInst &Inst, unsigned Insn,
109                                uint64_t Address, const void *Decoder);
110 static MCDisassembler::DecodeStatus DecodeAddrModeImm12Operand(llvm::MCInst &Inst, unsigned Val,
111                                uint64_t Address, const void *Decoder);
112 static MCDisassembler::DecodeStatus DecodeAddrMode5Operand(llvm::MCInst &Inst, unsigned Val,
113                                uint64_t Address, const void *Decoder);
114 static MCDisassembler::DecodeStatus DecodeAddrMode7Operand(llvm::MCInst &Inst, unsigned Val,
115                                uint64_t Address, const void *Decoder);
116 static MCDisassembler::DecodeStatus DecodeBranchImmInstruction(llvm::MCInst &Inst,unsigned Insn,
117                                uint64_t Address, const void *Decoder);
118 static MCDisassembler::DecodeStatus DecodeVCVTImmOperand(llvm::MCInst &Inst, unsigned Val,
119                                uint64_t Address, const void *Decoder);
120 static MCDisassembler::DecodeStatus DecodeAddrMode6Operand(llvm::MCInst &Inst, unsigned Val,
121                                uint64_t Address, const void *Decoder);
122 static MCDisassembler::DecodeStatus DecodeVLDInstruction(llvm::MCInst &Inst, unsigned Val,
123                                uint64_t Address, const void *Decoder);
124 static MCDisassembler::DecodeStatus DecodeVSTInstruction(llvm::MCInst &Inst, unsigned Val,
125                                uint64_t Address, const void *Decoder);
126 static MCDisassembler::DecodeStatus DecodeVLD1DupInstruction(llvm::MCInst &Inst, unsigned Val,
127                                uint64_t Address, const void *Decoder);
128 static MCDisassembler::DecodeStatus DecodeVLD2DupInstruction(llvm::MCInst &Inst, unsigned Val,
129                                uint64_t Address, const void *Decoder);
130 static MCDisassembler::DecodeStatus DecodeVLD3DupInstruction(llvm::MCInst &Inst, unsigned Val,
131                                uint64_t Address, const void *Decoder);
132 static MCDisassembler::DecodeStatus DecodeVLD4DupInstruction(llvm::MCInst &Inst, unsigned Val,
133                                uint64_t Address, const void *Decoder);
134 static MCDisassembler::DecodeStatus DecodeNEONModImmInstruction(llvm::MCInst &Inst,unsigned Val,
135                                uint64_t Address, const void *Decoder);
136 static MCDisassembler::DecodeStatus DecodeVSHLMaxInstruction(llvm::MCInst &Inst, unsigned Val,
137                                uint64_t Address, const void *Decoder);
138 static MCDisassembler::DecodeStatus DecodeShiftRight8Imm(llvm::MCInst &Inst, unsigned Val,
139                                uint64_t Address, const void *Decoder);
140 static MCDisassembler::DecodeStatus DecodeShiftRight16Imm(llvm::MCInst &Inst, unsigned Val,
141                                uint64_t Address, const void *Decoder);
142 static MCDisassembler::DecodeStatus DecodeShiftRight32Imm(llvm::MCInst &Inst, unsigned Val,
143                                uint64_t Address, const void *Decoder);
144 static MCDisassembler::DecodeStatus DecodeShiftRight64Imm(llvm::MCInst &Inst, unsigned Val,
145                                uint64_t Address, const void *Decoder);
146 static MCDisassembler::DecodeStatus DecodeTBLInstruction(llvm::MCInst &Inst, unsigned Insn,
147                                uint64_t Address, const void *Decoder);
148 static MCDisassembler::DecodeStatus DecodeVFPfpImm(llvm::MCInst &Inst, unsigned Val,
149                                uint64_t Address, const void *Decoder);
150 static MCDisassembler::DecodeStatus DecodePostIdxReg(llvm::MCInst &Inst, unsigned Insn,
151                                uint64_t Address, const void *Decoder);
152 static MCDisassembler::DecodeStatus DecodeCoprocessor(llvm::MCInst &Inst, unsigned Insn,
153                                uint64_t Address, const void *Decoder);
154 static MCDisassembler::DecodeStatus DecodeMemBarrierOption(llvm::MCInst &Inst, unsigned Insn,
155                                uint64_t Address, const void *Decoder);
156 static MCDisassembler::DecodeStatus DecodeMSRMask(llvm::MCInst &Inst, unsigned Insn,
157                                uint64_t Address, const void *Decoder);
158 static MCDisassembler::DecodeStatus DecodeDoubleRegLoad(llvm::MCInst &Inst, unsigned Insn,
159                                uint64_t Address, const void *Decoder);
160 static MCDisassembler::DecodeStatus DecodeDoubleRegStore(llvm::MCInst &Inst, unsigned Insn,
161                                uint64_t Address, const void *Decoder);
162 static MCDisassembler::DecodeStatus DecodeLDRPreImm(llvm::MCInst &Inst, unsigned Insn,
163                                uint64_t Address, const void *Decoder);
164 static MCDisassembler::DecodeStatus DecodeLDRPreReg(llvm::MCInst &Inst, unsigned Insn,
165                                uint64_t Address, const void *Decoder);
166 static MCDisassembler::DecodeStatus DecodeSTRPreImm(llvm::MCInst &Inst, unsigned Insn,
167                                uint64_t Address, const void *Decoder);
168 static MCDisassembler::DecodeStatus DecodeSTRPreReg(llvm::MCInst &Inst, unsigned Insn,
169                                uint64_t Address, const void *Decoder);
170 static MCDisassembler::DecodeStatus DecodeVLD1LN(llvm::MCInst &Inst, unsigned Insn,
171                                uint64_t Address, const void *Decoder);
172 static MCDisassembler::DecodeStatus DecodeVLD2LN(llvm::MCInst &Inst, unsigned Insn,
173                                uint64_t Address, const void *Decoder);
174 static MCDisassembler::DecodeStatus DecodeVLD3LN(llvm::MCInst &Inst, unsigned Insn,
175                                uint64_t Address, const void *Decoder);
176 static MCDisassembler::DecodeStatus DecodeVLD4LN(llvm::MCInst &Inst, unsigned Insn,
177                                uint64_t Address, const void *Decoder);
178 static MCDisassembler::DecodeStatus DecodeVST1LN(llvm::MCInst &Inst, unsigned Insn,
179                                uint64_t Address, const void *Decoder);
180 static MCDisassembler::DecodeStatus DecodeVST2LN(llvm::MCInst &Inst, unsigned Insn,
181                                uint64_t Address, const void *Decoder);
182 static MCDisassembler::DecodeStatus DecodeVST3LN(llvm::MCInst &Inst, unsigned Insn,
183                                uint64_t Address, const void *Decoder);
184 static MCDisassembler::DecodeStatus DecodeVST4LN(llvm::MCInst &Inst, unsigned Insn,
185                                uint64_t Address, const void *Decoder);
186 static MCDisassembler::DecodeStatus DecodeVMOVSRR(llvm::MCInst &Inst, unsigned Insn,
187                                uint64_t Address, const void *Decoder);
188 static MCDisassembler::DecodeStatus DecodeVMOVRRS(llvm::MCInst &Inst, unsigned Insn,
189                                uint64_t Address, const void *Decoder);
190 
191 static MCDisassembler::DecodeStatus DecodeThumbAddSpecialReg(llvm::MCInst &Inst, uint16_t Insn,
192                                uint64_t Address, const void *Decoder);
193 static MCDisassembler::DecodeStatus DecodeThumbBROperand(llvm::MCInst &Inst, unsigned Val,
194                                uint64_t Address, const void *Decoder);
195 static MCDisassembler::DecodeStatus DecodeT2BROperand(llvm::MCInst &Inst, unsigned Val,
196                                uint64_t Address, const void *Decoder);
197 static MCDisassembler::DecodeStatus DecodeThumbCmpBROperand(llvm::MCInst &Inst, unsigned Val,
198                                uint64_t Address, const void *Decoder);
199 static MCDisassembler::DecodeStatus DecodeThumbAddrModeRR(llvm::MCInst &Inst, unsigned Val,
200                                uint64_t Address, const void *Decoder);
201 static MCDisassembler::DecodeStatus DecodeThumbAddrModeIS(llvm::MCInst &Inst, unsigned Val,
202                                uint64_t Address, const void *Decoder);
203 static MCDisassembler::DecodeStatus DecodeThumbAddrModePC(llvm::MCInst &Inst, unsigned Val,
204                                uint64_t Address, const void *Decoder);
205 static MCDisassembler::DecodeStatus DecodeThumbAddrModeSP(llvm::MCInst &Inst, unsigned Val,
206                                uint64_t Address, const void *Decoder);
207 static MCDisassembler::DecodeStatus DecodeT2AddrModeSOReg(llvm::MCInst &Inst, unsigned Val,
208                                uint64_t Address, const void *Decoder);
209 static MCDisassembler::DecodeStatus DecodeT2LoadShift(llvm::MCInst &Inst, unsigned Val,
210                                uint64_t Address, const void *Decoder);
211 static MCDisassembler::DecodeStatus DecodeT2Imm8S4(llvm::MCInst &Inst, unsigned Val,
212                                uint64_t Address, const void *Decoder);
213 static MCDisassembler::DecodeStatus DecodeT2AddrModeImm8s4(llvm::MCInst &Inst, unsigned Val,
214                                uint64_t Address, const void *Decoder);
215 static MCDisassembler::DecodeStatus DecodeT2Imm8(llvm::MCInst &Inst, unsigned Val,
216                                uint64_t Address, const void *Decoder);
217 static MCDisassembler::DecodeStatus DecodeT2AddrModeImm8(llvm::MCInst &Inst, unsigned Val,
218                                uint64_t Address, const void *Decoder);
219 static MCDisassembler::DecodeStatus DecodeThumbAddSPImm(llvm::MCInst &Inst, uint16_t Val,
220                                uint64_t Address, const void *Decoder);
221 static MCDisassembler::DecodeStatus DecodeThumbAddSPReg(llvm::MCInst &Inst, uint16_t Insn,
222                                 uint64_t Address, const void *Decoder);
223 static MCDisassembler::DecodeStatus DecodeThumbCPS(llvm::MCInst &Inst, uint16_t Insn,
224                                 uint64_t Address, const void *Decoder);
225 static MCDisassembler::DecodeStatus DecodeThumbBLXOffset(llvm::MCInst &Inst, unsigned Insn,
226                                 uint64_t Address, const void *Decoder);
227 static MCDisassembler::DecodeStatus DecodeT2AddrModeImm12(llvm::MCInst &Inst, unsigned Val,
228                                 uint64_t Address, const void *Decoder);
229 static MCDisassembler::DecodeStatus DecodeThumb2BCCInstruction(llvm::MCInst &Inst, unsigned Val,
230                                 uint64_t Address, const void *Decoder);
231 static MCDisassembler::DecodeStatus DecodeT2SOImm(llvm::MCInst &Inst, unsigned Val,
232                                 uint64_t Address, const void *Decoder);
233 static MCDisassembler::DecodeStatus DecodeThumbBCCTargetOperand(llvm::MCInst &Inst,unsigned Val,
234                                 uint64_t Address, const void *Decoder);
235 static MCDisassembler::DecodeStatus DecodeThumbBLTargetOperand(llvm::MCInst &Inst, unsigned Val,
236                                 uint64_t Address, const void *Decoder);
237 static MCDisassembler::DecodeStatus DecodeIT(llvm::MCInst &Inst, unsigned Val,
238                                 uint64_t Address, const void *Decoder);
239 
240 #include "ARMGenDisassemblerTables.inc"
241 #include "ARMGenInstrInfo.inc"
242 #include "ARMGenEDInfo.inc"
243 
244 static MCDisassembler *createARMDisassembler(const Target &T) {
245   return new ARMDisassembler;
246 }
247 
248 static MCDisassembler *createThumbDisassembler(const Target &T) {
249   return new ThumbDisassembler;
250 }
251 
252 EDInstInfo *ARMDisassembler::getEDInfo() const {
253   return instInfoARM;
254 }
255 
256 EDInstInfo *ThumbDisassembler::getEDInfo() const {
257   return instInfoARM;
258 }
259 
260 MCDisassembler::DecodeStatus ARMDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
261                                              const MemoryObject &Region,
262                                              uint64_t Address,
263                                              raw_ostream &os) const {
264   uint8_t bytes[4];
265 
266   // We want to read exactly 4 bytes of data.
267   if (Region.readBytes(Address, 4, (uint8_t*)bytes, NULL) == -1) {
268     Size = 0;
269     return MCDisassembler::Fail;
270   }
271 
272   // Encoded as a small-endian 32-bit word in the stream.
273   uint32_t insn = (bytes[3] << 24) |
274                   (bytes[2] << 16) |
275                   (bytes[1] <<  8) |
276                   (bytes[0] <<  0);
277 
278   // Calling the auto-generated decoder function.
279   MCDisassembler::DecodeStatus result = decodeARMInstruction32(MI, insn, Address, this);
280   if (result != MCDisassembler::Fail) {
281     Size = 4;
282     return result;
283   }
284 
285   // Instructions that are shared between ARM and Thumb modes.
286   // FIXME: This shouldn't really exist.  It's an artifact of the
287   // fact that we fail to encode a few instructions properly for Thumb.
288   MI.clear();
289   result = decodeCommonInstruction32(MI, insn, Address, this);
290   if (result != MCDisassembler::Fail) {
291     Size = 4;
292     return result;
293   }
294 
295   // VFP and NEON instructions, similarly, are shared between ARM
296   // and Thumb modes.
297   MI.clear();
298   result = decodeVFPInstruction32(MI, insn, Address, this);
299   if (result != MCDisassembler::Fail) {
300     Size = 4;
301     return result;
302   }
303 
304   MI.clear();
305   result = decodeNEONDataInstruction32(MI, insn, Address, this);
306   if (result != MCDisassembler::Fail) {
307     Size = 4;
308     // Add a fake predicate operand, because we share these instruction
309     // definitions with Thumb2 where these instructions are predicable.
310     if (!DecodePredicateOperand(MI, 0xE, Address, this)) return MCDisassembler::Fail;
311     return result;
312   }
313 
314   MI.clear();
315   result = decodeNEONLoadStoreInstruction32(MI, insn, Address, this);
316   if (result != MCDisassembler::Fail) {
317     Size = 4;
318     // Add a fake predicate operand, because we share these instruction
319     // definitions with Thumb2 where these instructions are predicable.
320     if (!DecodePredicateOperand(MI, 0xE, Address, this)) return MCDisassembler::Fail;
321     return result;
322   }
323 
324   MI.clear();
325   result = decodeNEONDupInstruction32(MI, insn, Address, this);
326   if (result != MCDisassembler::Fail) {
327     Size = 4;
328     // Add a fake predicate operand, because we share these instruction
329     // definitions with Thumb2 where these instructions are predicable.
330     if (!DecodePredicateOperand(MI, 0xE, Address, this)) return MCDisassembler::Fail;
331     return result;
332   }
333 
334   MI.clear();
335 
336   Size = 0;
337   return MCDisassembler::Fail;
338 }
339 
340 namespace llvm {
341 extern MCInstrDesc ARMInsts[];
342 }
343 
344 // Thumb1 instructions don't have explicit S bits.  Rather, they
345 // implicitly set CPSR.  Since it's not represented in the encoding, the
346 // auto-generated decoder won't inject the CPSR operand.  We need to fix
347 // that as a post-pass.
348 static void AddThumb1SBit(MCInst &MI, bool InITBlock) {
349   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
350   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
351   MCInst::iterator I = MI.begin();
352   for (unsigned i = 0; i < NumOps; ++i, ++I) {
353     if (I == MI.end()) break;
354     if (OpInfo[i].isOptionalDef() && OpInfo[i].RegClass == ARM::CCRRegClassID) {
355       if (i > 0 && OpInfo[i-1].isPredicate()) continue;
356       MI.insert(I, MCOperand::CreateReg(InITBlock ? 0 : ARM::CPSR));
357       return;
358     }
359   }
360 
361   MI.insert(I, MCOperand::CreateReg(InITBlock ? 0 : ARM::CPSR));
362 }
363 
364 // Most Thumb instructions don't have explicit predicates in the
365 // encoding, but rather get their predicates from IT context.  We need
366 // to fix up the predicate operands using this context information as a
367 // post-pass.
368 void ThumbDisassembler::AddThumbPredicate(MCInst &MI) const {
369   // A few instructions actually have predicates encoded in them.  Don't
370   // try to overwrite it if we're seeing one of those.
371   switch (MI.getOpcode()) {
372     case ARM::tBcc:
373     case ARM::t2Bcc:
374       return;
375     default:
376       break;
377   }
378 
379   // If we're in an IT block, base the predicate on that.  Otherwise,
380   // assume a predicate of AL.
381   unsigned CC;
382   if (!ITBlock.empty()) {
383     CC = ITBlock.back();
384     if (CC == 0xF)
385       CC = ARMCC::AL;
386     ITBlock.pop_back();
387   } else
388     CC = ARMCC::AL;
389 
390   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
391   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
392   MCInst::iterator I = MI.begin();
393   for (unsigned i = 0; i < NumOps; ++i, ++I) {
394     if (I == MI.end()) break;
395     if (OpInfo[i].isPredicate()) {
396       I = MI.insert(I, MCOperand::CreateImm(CC));
397       ++I;
398       if (CC == ARMCC::AL)
399         MI.insert(I, MCOperand::CreateReg(0));
400       else
401         MI.insert(I, MCOperand::CreateReg(ARM::CPSR));
402       return;
403     }
404   }
405 
406   I = MI.insert(I, MCOperand::CreateImm(CC));
407   ++I;
408   if (CC == ARMCC::AL)
409     MI.insert(I, MCOperand::CreateReg(0));
410   else
411     MI.insert(I, MCOperand::CreateReg(ARM::CPSR));
412 }
413 
414 // Thumb VFP instructions are a special case.  Because we share their
415 // encodings between ARM and Thumb modes, and they are predicable in ARM
416 // mode, the auto-generated decoder will give them an (incorrect)
417 // predicate operand.  We need to rewrite these operands based on the IT
418 // context as a post-pass.
419 void ThumbDisassembler::UpdateThumbVFPPredicate(MCInst &MI) const {
420   unsigned CC;
421   if (!ITBlock.empty()) {
422     CC = ITBlock.back();
423     ITBlock.pop_back();
424   } else
425     CC = ARMCC::AL;
426 
427   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
428   MCInst::iterator I = MI.begin();
429   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
430   for (unsigned i = 0; i < NumOps; ++i, ++I) {
431     if (OpInfo[i].isPredicate() ) {
432       I->setImm(CC);
433       ++I;
434       if (CC == ARMCC::AL)
435         I->setReg(0);
436       else
437         I->setReg(ARM::CPSR);
438       return;
439     }
440   }
441 }
442 
443 MCDisassembler::DecodeStatus ThumbDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
444                                                const MemoryObject &Region,
445                                                uint64_t Address,
446                                                raw_ostream &os) const {
447   uint8_t bytes[4];
448 
449   // We want to read exactly 2 bytes of data.
450   if (Region.readBytes(Address, 2, (uint8_t*)bytes, NULL) == -1) {
451     Size = 0;
452     return MCDisassembler::Fail;
453   }
454 
455   uint16_t insn16 = (bytes[1] << 8) | bytes[0];
456   MCDisassembler::DecodeStatus result = decodeThumbInstruction16(MI, insn16, Address, this);
457   if (result != MCDisassembler::Fail) {
458     Size = 2;
459     AddThumbPredicate(MI);
460     return result;
461   }
462 
463   MI.clear();
464   result = decodeThumbSBitInstruction16(MI, insn16, Address, this);
465   if (result) {
466     Size = 2;
467     bool InITBlock = !ITBlock.empty();
468     AddThumbPredicate(MI);
469     AddThumb1SBit(MI, InITBlock);
470     return result;
471   }
472 
473   MI.clear();
474   result = decodeThumb2Instruction16(MI, insn16, Address, this);
475   if (result != MCDisassembler::Fail) {
476     Size = 2;
477     AddThumbPredicate(MI);
478 
479     // If we find an IT instruction, we need to parse its condition
480     // code and mask operands so that we can apply them correctly
481     // to the subsequent instructions.
482     if (MI.getOpcode() == ARM::t2IT) {
483       // (3 - the number of trailing zeros) is the number of then / else.
484       unsigned firstcond = MI.getOperand(0).getImm();
485       unsigned Mask = MI.getOperand(1).getImm();
486       unsigned CondBit0 = Mask >> 4 & 1;
487       unsigned NumTZ = CountTrailingZeros_32(Mask);
488       assert(NumTZ <= 3 && "Invalid IT mask!");
489       for (unsigned Pos = 3, e = NumTZ; Pos > e; --Pos) {
490         bool T = ((Mask >> Pos) & 1) == CondBit0;
491         if (T)
492           ITBlock.insert(ITBlock.begin(), firstcond);
493         else
494           ITBlock.insert(ITBlock.begin(), firstcond ^ 1);
495       }
496 
497       ITBlock.push_back(firstcond);
498     }
499 
500     return result;
501   }
502 
503   // We want to read exactly 4 bytes of data.
504   if (Region.readBytes(Address, 4, (uint8_t*)bytes, NULL) == -1) {
505     Size = 0;
506     return MCDisassembler::Fail;
507   }
508 
509   uint32_t insn32 = (bytes[3] <<  8) |
510                     (bytes[2] <<  0) |
511                     (bytes[1] << 24) |
512                     (bytes[0] << 16);
513   MI.clear();
514   result = decodeThumbInstruction32(MI, insn32, Address, this);
515   if (result != MCDisassembler::Fail) {
516     Size = 4;
517     bool InITBlock = ITBlock.size();
518     AddThumbPredicate(MI);
519     AddThumb1SBit(MI, InITBlock);
520     return result;
521   }
522 
523   MI.clear();
524   result = decodeThumb2Instruction32(MI, insn32, Address, this);
525   if (result != MCDisassembler::Fail) {
526     Size = 4;
527     AddThumbPredicate(MI);
528     return result;
529   }
530 
531   MI.clear();
532   result = decodeCommonInstruction32(MI, insn32, Address, this);
533   if (result != MCDisassembler::Fail) {
534     Size = 4;
535     AddThumbPredicate(MI);
536     return result;
537   }
538 
539   MI.clear();
540   result = decodeVFPInstruction32(MI, insn32, Address, this);
541   if (result != MCDisassembler::Fail) {
542     Size = 4;
543     UpdateThumbVFPPredicate(MI);
544     return result;
545   }
546 
547   MI.clear();
548   result = decodeNEONDupInstruction32(MI, insn32, Address, this);
549   if (result != MCDisassembler::Fail) {
550     Size = 4;
551     AddThumbPredicate(MI);
552     return result;
553   }
554 
555   if (fieldFromInstruction32(insn32, 24, 8) == 0xF9) {
556     MI.clear();
557     uint32_t NEONLdStInsn = insn32;
558     NEONLdStInsn &= 0xF0FFFFFF;
559     NEONLdStInsn |= 0x04000000;
560     result = decodeNEONLoadStoreInstruction32(MI, NEONLdStInsn, Address, this);
561     if (result != MCDisassembler::Fail) {
562       Size = 4;
563       AddThumbPredicate(MI);
564       return result;
565     }
566   }
567 
568   if (fieldFromInstruction32(insn32, 24, 4) == 0xF) {
569     MI.clear();
570     uint32_t NEONDataInsn = insn32;
571     NEONDataInsn &= 0xF0FFFFFF; // Clear bits 27-24
572     NEONDataInsn |= (NEONDataInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
573     NEONDataInsn |= 0x12000000; // Set bits 28 and 25
574     result = decodeNEONDataInstruction32(MI, NEONDataInsn, Address, this);
575     if (result != MCDisassembler::Fail) {
576       Size = 4;
577       AddThumbPredicate(MI);
578       return result;
579     }
580   }
581 
582   Size = 0;
583   return MCDisassembler::Fail;
584 }
585 
586 
587 extern "C" void LLVMInitializeARMDisassembler() {
588   TargetRegistry::RegisterMCDisassembler(TheARMTarget,
589                                          createARMDisassembler);
590   TargetRegistry::RegisterMCDisassembler(TheThumbTarget,
591                                          createThumbDisassembler);
592 }
593 
594 static const unsigned GPRDecoderTable[] = {
595   ARM::R0, ARM::R1, ARM::R2, ARM::R3,
596   ARM::R4, ARM::R5, ARM::R6, ARM::R7,
597   ARM::R8, ARM::R9, ARM::R10, ARM::R11,
598   ARM::R12, ARM::SP, ARM::LR, ARM::PC
599 };
600 
601 static MCDisassembler::DecodeStatus DecodeGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
602                                    uint64_t Address, const void *Decoder) {
603   if (RegNo > 15)
604     return MCDisassembler::Fail;
605 
606   unsigned Register = GPRDecoderTable[RegNo];
607   Inst.addOperand(MCOperand::CreateReg(Register));
608   return MCDisassembler::Success;
609 }
610 
611 static MCDisassembler::DecodeStatus
612 DecodeGPRnopcRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
613                            uint64_t Address, const void *Decoder) {
614   if (RegNo == 15) return MCDisassembler::Fail;
615   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
616 }
617 
618 static MCDisassembler::DecodeStatus DecodetGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
619                                    uint64_t Address, const void *Decoder) {
620   if (RegNo > 7)
621     return MCDisassembler::Fail;
622   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
623 }
624 
625 static MCDisassembler::DecodeStatus DecodetcGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
626                                    uint64_t Address, const void *Decoder) {
627   unsigned Register = 0;
628   switch (RegNo) {
629     case 0:
630       Register = ARM::R0;
631       break;
632     case 1:
633       Register = ARM::R1;
634       break;
635     case 2:
636       Register = ARM::R2;
637       break;
638     case 3:
639       Register = ARM::R3;
640       break;
641     case 9:
642       Register = ARM::R9;
643       break;
644     case 12:
645       Register = ARM::R12;
646       break;
647     default:
648       return MCDisassembler::Fail;
649     }
650 
651   Inst.addOperand(MCOperand::CreateReg(Register));
652   return MCDisassembler::Success;
653 }
654 
655 static MCDisassembler::DecodeStatus DecoderGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
656                                    uint64_t Address, const void *Decoder) {
657   if (RegNo == 13 || RegNo == 15) return MCDisassembler::Fail;
658   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
659 }
660 
661 static const unsigned SPRDecoderTable[] = {
662      ARM::S0,  ARM::S1,  ARM::S2,  ARM::S3,
663      ARM::S4,  ARM::S5,  ARM::S6,  ARM::S7,
664      ARM::S8,  ARM::S9, ARM::S10, ARM::S11,
665     ARM::S12, ARM::S13, ARM::S14, ARM::S15,
666     ARM::S16, ARM::S17, ARM::S18, ARM::S19,
667     ARM::S20, ARM::S21, ARM::S22, ARM::S23,
668     ARM::S24, ARM::S25, ARM::S26, ARM::S27,
669     ARM::S28, ARM::S29, ARM::S30, ARM::S31
670 };
671 
672 static MCDisassembler::DecodeStatus DecodeSPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
673                                    uint64_t Address, const void *Decoder) {
674   if (RegNo > 31)
675     return MCDisassembler::Fail;
676 
677   unsigned Register = SPRDecoderTable[RegNo];
678   Inst.addOperand(MCOperand::CreateReg(Register));
679   return MCDisassembler::Success;
680 }
681 
682 static const unsigned DPRDecoderTable[] = {
683      ARM::D0,  ARM::D1,  ARM::D2,  ARM::D3,
684      ARM::D4,  ARM::D5,  ARM::D6,  ARM::D7,
685      ARM::D8,  ARM::D9, ARM::D10, ARM::D11,
686     ARM::D12, ARM::D13, ARM::D14, ARM::D15,
687     ARM::D16, ARM::D17, ARM::D18, ARM::D19,
688     ARM::D20, ARM::D21, ARM::D22, ARM::D23,
689     ARM::D24, ARM::D25, ARM::D26, ARM::D27,
690     ARM::D28, ARM::D29, ARM::D30, ARM::D31
691 };
692 
693 static MCDisassembler::DecodeStatus DecodeDPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
694                                    uint64_t Address, const void *Decoder) {
695   if (RegNo > 31)
696     return MCDisassembler::Fail;
697 
698   unsigned Register = DPRDecoderTable[RegNo];
699   Inst.addOperand(MCOperand::CreateReg(Register));
700   return MCDisassembler::Success;
701 }
702 
703 static MCDisassembler::DecodeStatus DecodeDPR_8RegisterClass(llvm::MCInst &Inst, unsigned RegNo,
704                                    uint64_t Address, const void *Decoder) {
705   if (RegNo > 7)
706     return MCDisassembler::Fail;
707   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
708 }
709 
710 static MCDisassembler::DecodeStatus
711 DecodeDPR_VFP2RegisterClass(llvm::MCInst &Inst, unsigned RegNo,
712                             uint64_t Address, const void *Decoder) {
713   if (RegNo > 15)
714     return MCDisassembler::Fail;
715   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
716 }
717 
718 static const unsigned QPRDecoderTable[] = {
719      ARM::Q0,  ARM::Q1,  ARM::Q2,  ARM::Q3,
720      ARM::Q4,  ARM::Q5,  ARM::Q6,  ARM::Q7,
721      ARM::Q8,  ARM::Q9, ARM::Q10, ARM::Q11,
722     ARM::Q12, ARM::Q13, ARM::Q14, ARM::Q15
723 };
724 
725 
726 static MCDisassembler::DecodeStatus DecodeQPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
727                                    uint64_t Address, const void *Decoder) {
728   if (RegNo > 31)
729     return MCDisassembler::Fail;
730   RegNo >>= 1;
731 
732   unsigned Register = QPRDecoderTable[RegNo];
733   Inst.addOperand(MCOperand::CreateReg(Register));
734   return MCDisassembler::Success;
735 }
736 
737 static MCDisassembler::DecodeStatus DecodePredicateOperand(llvm::MCInst &Inst, unsigned Val,
738                                uint64_t Address, const void *Decoder) {
739   if (Val == 0xF) return MCDisassembler::Fail;
740   // AL predicate is not allowed on Thumb1 branches.
741   if (Inst.getOpcode() == ARM::tBcc && Val == 0xE)
742     return MCDisassembler::Fail;
743   Inst.addOperand(MCOperand::CreateImm(Val));
744   if (Val == ARMCC::AL) {
745     Inst.addOperand(MCOperand::CreateReg(0));
746   } else
747     Inst.addOperand(MCOperand::CreateReg(ARM::CPSR));
748   return MCDisassembler::Success;
749 }
750 
751 static MCDisassembler::DecodeStatus DecodeCCOutOperand(llvm::MCInst &Inst, unsigned Val,
752                                uint64_t Address, const void *Decoder) {
753   if (Val)
754     Inst.addOperand(MCOperand::CreateReg(ARM::CPSR));
755   else
756     Inst.addOperand(MCOperand::CreateReg(0));
757   return MCDisassembler::Success;
758 }
759 
760 static MCDisassembler::DecodeStatus DecodeSOImmOperand(llvm::MCInst &Inst, unsigned Val,
761                                uint64_t Address, const void *Decoder) {
762   uint32_t imm = Val & 0xFF;
763   uint32_t rot = (Val & 0xF00) >> 7;
764   uint32_t rot_imm = (imm >> rot) | (imm << (32-rot));
765   Inst.addOperand(MCOperand::CreateImm(rot_imm));
766   return MCDisassembler::Success;
767 }
768 
769 static MCDisassembler::DecodeStatus DecodeSORegImmOperand(llvm::MCInst &Inst, unsigned Val,
770                                uint64_t Address, const void *Decoder) {
771   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
772 
773   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
774   unsigned type = fieldFromInstruction32(Val, 5, 2);
775   unsigned imm = fieldFromInstruction32(Val, 7, 5);
776 
777   // Register-immediate
778   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))) return MCDisassembler::Fail;
779 
780   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
781   switch (type) {
782     case 0:
783       Shift = ARM_AM::lsl;
784       break;
785     case 1:
786       Shift = ARM_AM::lsr;
787       break;
788     case 2:
789       Shift = ARM_AM::asr;
790       break;
791     case 3:
792       Shift = ARM_AM::ror;
793       break;
794   }
795 
796   if (Shift == ARM_AM::ror && imm == 0)
797     Shift = ARM_AM::rrx;
798 
799   unsigned Op = Shift | (imm << 3);
800   Inst.addOperand(MCOperand::CreateImm(Op));
801 
802   return S;
803 }
804 
805 static MCDisassembler::DecodeStatus DecodeSORegRegOperand(llvm::MCInst &Inst, unsigned Val,
806                                uint64_t Address, const void *Decoder) {
807   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
808 
809   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
810   unsigned type = fieldFromInstruction32(Val, 5, 2);
811   unsigned Rs = fieldFromInstruction32(Val, 8, 4);
812 
813   // Register-register
814   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder))) return MCDisassembler::Fail;
815   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rs, Address, Decoder))) return MCDisassembler::Fail;
816 
817   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
818   switch (type) {
819     case 0:
820       Shift = ARM_AM::lsl;
821       break;
822     case 1:
823       Shift = ARM_AM::lsr;
824       break;
825     case 2:
826       Shift = ARM_AM::asr;
827       break;
828     case 3:
829       Shift = ARM_AM::ror;
830       break;
831   }
832 
833   Inst.addOperand(MCOperand::CreateImm(Shift));
834 
835   return S;
836 }
837 
838 static MCDisassembler::DecodeStatus DecodeRegListOperand(llvm::MCInst &Inst, unsigned Val,
839                                  uint64_t Address, const void *Decoder) {
840   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
841 
842   // Empty register lists are not allowed.
843   if (CountPopulation_32(Val) == 0) return MCDisassembler::Fail;
844   for (unsigned i = 0; i < 16; ++i) {
845     if (Val & (1 << i)) {
846       if (!Check(S, DecodeGPRRegisterClass(Inst, i, Address, Decoder))) return MCDisassembler::Fail;
847     }
848   }
849 
850   return S;
851 }
852 
853 static MCDisassembler::DecodeStatus DecodeSPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
854                                  uint64_t Address, const void *Decoder) {
855   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
856 
857   unsigned Vd = fieldFromInstruction32(Val, 8, 4);
858   unsigned regs = Val & 0xFF;
859 
860   if (!Check(S, DecodeSPRRegisterClass(Inst, Vd, Address, Decoder))) return MCDisassembler::Fail;
861   for (unsigned i = 0; i < (regs - 1); ++i) {
862     if (!Check(S, DecodeSPRRegisterClass(Inst, ++Vd, Address, Decoder))) return MCDisassembler::Fail;
863   }
864 
865   return S;
866 }
867 
868 static MCDisassembler::DecodeStatus DecodeDPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
869                                  uint64_t Address, const void *Decoder) {
870   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
871 
872   unsigned Vd = fieldFromInstruction32(Val, 8, 4);
873   unsigned regs = (Val & 0xFF) / 2;
874 
875   if (!Check(S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder))) return MCDisassembler::Fail;
876   for (unsigned i = 0; i < (regs - 1); ++i) {
877     if (!Check(S, DecodeDPRRegisterClass(Inst, ++Vd, Address, Decoder))) return MCDisassembler::Fail;
878   }
879 
880   return S;
881 }
882 
883 static MCDisassembler::DecodeStatus DecodeBitfieldMaskOperand(llvm::MCInst &Inst, unsigned Val,
884                                       uint64_t Address, const void *Decoder) {
885   // This operand encodes a mask of contiguous zeros between a specified MSB
886   // and LSB.  To decode it, we create the mask of all bits MSB-and-lower,
887   // the mask of all bits LSB-and-lower, and then xor them to create
888   // the mask of that's all ones on [msb, lsb].  Finally we not it to
889   // create the final mask.
890   unsigned msb = fieldFromInstruction32(Val, 5, 5);
891   unsigned lsb = fieldFromInstruction32(Val, 0, 5);
892   uint32_t msb_mask = (1 << (msb+1)) - 1;
893   uint32_t lsb_mask = (1 << lsb) - 1;
894   Inst.addOperand(MCOperand::CreateImm(~(msb_mask ^ lsb_mask)));
895   return MCDisassembler::Success;
896 }
897 
898 static MCDisassembler::DecodeStatus DecodeCopMemInstruction(llvm::MCInst &Inst, unsigned Insn,
899                                   uint64_t Address, const void *Decoder) {
900   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
901 
902   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
903   unsigned CRd = fieldFromInstruction32(Insn, 12, 4);
904   unsigned coproc = fieldFromInstruction32(Insn, 8, 4);
905   unsigned imm = fieldFromInstruction32(Insn, 0, 8);
906   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
907   unsigned U = fieldFromInstruction32(Insn, 23, 1);
908 
909   switch (Inst.getOpcode()) {
910     case ARM::LDC_OFFSET:
911     case ARM::LDC_PRE:
912     case ARM::LDC_POST:
913     case ARM::LDC_OPTION:
914     case ARM::LDCL_OFFSET:
915     case ARM::LDCL_PRE:
916     case ARM::LDCL_POST:
917     case ARM::LDCL_OPTION:
918     case ARM::STC_OFFSET:
919     case ARM::STC_PRE:
920     case ARM::STC_POST:
921     case ARM::STC_OPTION:
922     case ARM::STCL_OFFSET:
923     case ARM::STCL_PRE:
924     case ARM::STCL_POST:
925     case ARM::STCL_OPTION:
926       if (coproc == 0xA || coproc == 0xB)
927         return MCDisassembler::Fail;
928       break;
929     default:
930       break;
931   }
932 
933   Inst.addOperand(MCOperand::CreateImm(coproc));
934   Inst.addOperand(MCOperand::CreateImm(CRd));
935   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
936   switch (Inst.getOpcode()) {
937     case ARM::LDC_OPTION:
938     case ARM::LDCL_OPTION:
939     case ARM::LDC2_OPTION:
940     case ARM::LDC2L_OPTION:
941     case ARM::STC_OPTION:
942     case ARM::STCL_OPTION:
943     case ARM::STC2_OPTION:
944     case ARM::STC2L_OPTION:
945     case ARM::LDCL_POST:
946     case ARM::STCL_POST:
947     case ARM::LDC2L_POST:
948     case ARM::STC2L_POST:
949       break;
950     default:
951       Inst.addOperand(MCOperand::CreateReg(0));
952       break;
953   }
954 
955   unsigned P = fieldFromInstruction32(Insn, 24, 1);
956   unsigned W = fieldFromInstruction32(Insn, 21, 1);
957 
958   bool writeback = (P == 0) || (W == 1);
959   unsigned idx_mode = 0;
960   if (P && writeback)
961     idx_mode = ARMII::IndexModePre;
962   else if (!P && writeback)
963     idx_mode = ARMII::IndexModePost;
964 
965   switch (Inst.getOpcode()) {
966     case ARM::LDCL_POST:
967     case ARM::STCL_POST:
968     case ARM::LDC2L_POST:
969     case ARM::STC2L_POST:
970       imm |= U << 8;
971     case ARM::LDC_OPTION:
972     case ARM::LDCL_OPTION:
973     case ARM::LDC2_OPTION:
974     case ARM::LDC2L_OPTION:
975     case ARM::STC_OPTION:
976     case ARM::STCL_OPTION:
977     case ARM::STC2_OPTION:
978     case ARM::STC2L_OPTION:
979       Inst.addOperand(MCOperand::CreateImm(imm));
980       break;
981     default:
982       if (U)
983         Inst.addOperand(MCOperand::CreateImm(
984             ARM_AM::getAM2Opc(ARM_AM::add, imm, ARM_AM::lsl, idx_mode)));
985       else
986         Inst.addOperand(MCOperand::CreateImm(
987             ARM_AM::getAM2Opc(ARM_AM::sub, imm, ARM_AM::lsl, idx_mode)));
988       break;
989   }
990 
991   switch (Inst.getOpcode()) {
992     case ARM::LDC_OFFSET:
993     case ARM::LDC_PRE:
994     case ARM::LDC_POST:
995     case ARM::LDC_OPTION:
996     case ARM::LDCL_OFFSET:
997     case ARM::LDCL_PRE:
998     case ARM::LDCL_POST:
999     case ARM::LDCL_OPTION:
1000     case ARM::STC_OFFSET:
1001     case ARM::STC_PRE:
1002     case ARM::STC_POST:
1003     case ARM::STC_OPTION:
1004     case ARM::STCL_OFFSET:
1005     case ARM::STCL_PRE:
1006     case ARM::STCL_POST:
1007     case ARM::STCL_OPTION:
1008       if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder))) return MCDisassembler::Fail;
1009       break;
1010     default:
1011       break;
1012   }
1013 
1014   return S;
1015 }
1016 
1017 static MCDisassembler::DecodeStatus
1018 DecodeAddrMode2IdxInstruction(llvm::MCInst &Inst, unsigned Insn,
1019                               uint64_t Address, const void *Decoder) {
1020   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
1021 
1022   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1023   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
1024   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1025   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
1026   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1027   unsigned reg = fieldFromInstruction32(Insn, 25, 1);
1028   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1029   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1030 
1031   // On stores, the writeback operand precedes Rt.
1032   switch (Inst.getOpcode()) {
1033     case ARM::STR_POST_IMM:
1034     case ARM::STR_POST_REG:
1035     case ARM::STRB_POST_IMM:
1036     case ARM::STRB_POST_REG:
1037     case ARM::STRT_POST_REG:
1038     case ARM::STRT_POST_IMM:
1039     case ARM::STRBT_POST_REG:
1040     case ARM::STRBT_POST_IMM:
1041       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
1042       break;
1043     default:
1044       break;
1045   }
1046 
1047   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder))) return MCDisassembler::Fail;
1048 
1049   // On loads, the writeback operand comes after Rt.
1050   switch (Inst.getOpcode()) {
1051     case ARM::LDR_POST_IMM:
1052     case ARM::LDR_POST_REG:
1053     case ARM::LDRB_POST_IMM:
1054     case ARM::LDRB_POST_REG:
1055     case ARM::LDRBT_POST_REG:
1056     case ARM::LDRBT_POST_IMM:
1057     case ARM::LDRT_POST_REG:
1058     case ARM::LDRT_POST_IMM:
1059       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
1060       break;
1061     default:
1062       break;
1063   }
1064 
1065   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
1066 
1067   ARM_AM::AddrOpc Op = ARM_AM::add;
1068   if (!fieldFromInstruction32(Insn, 23, 1))
1069     Op = ARM_AM::sub;
1070 
1071   bool writeback = (P == 0) || (W == 1);
1072   unsigned idx_mode = 0;
1073   if (P && writeback)
1074     idx_mode = ARMII::IndexModePre;
1075   else if (!P && writeback)
1076     idx_mode = ARMII::IndexModePost;
1077 
1078   if (writeback && (Rn == 15 || Rn == Rt)) S = MCDisassembler::SoftFail; // UNPREDICTABLE
1079 
1080   if (reg) {
1081     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder))) return MCDisassembler::Fail;
1082     ARM_AM::ShiftOpc Opc = ARM_AM::lsl;
1083     switch( fieldFromInstruction32(Insn, 5, 2)) {
1084       case 0:
1085         Opc = ARM_AM::lsl;
1086         break;
1087       case 1:
1088         Opc = ARM_AM::lsr;
1089         break;
1090       case 2:
1091         Opc = ARM_AM::asr;
1092         break;
1093       case 3:
1094         Opc = ARM_AM::ror;
1095         break;
1096       default:
1097         return MCDisassembler::Fail;
1098     }
1099     unsigned amt = fieldFromInstruction32(Insn, 7, 5);
1100     unsigned imm = ARM_AM::getAM2Opc(Op, amt, Opc, idx_mode);
1101 
1102     Inst.addOperand(MCOperand::CreateImm(imm));
1103   } else {
1104     Inst.addOperand(MCOperand::CreateReg(0));
1105     unsigned tmp = ARM_AM::getAM2Opc(Op, imm, ARM_AM::lsl, idx_mode);
1106     Inst.addOperand(MCOperand::CreateImm(tmp));
1107   }
1108 
1109   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder))) return MCDisassembler::Fail;
1110 
1111   return S;
1112 }
1113 
1114 static MCDisassembler::DecodeStatus DecodeSORegMemOperand(llvm::MCInst &Inst, unsigned Val,
1115                                   uint64_t Address, const void *Decoder) {
1116   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
1117 
1118   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
1119   unsigned Rm = fieldFromInstruction32(Val,  0, 4);
1120   unsigned type = fieldFromInstruction32(Val, 5, 2);
1121   unsigned imm = fieldFromInstruction32(Val, 7, 5);
1122   unsigned U = fieldFromInstruction32(Val, 12, 1);
1123 
1124   ARM_AM::ShiftOpc ShOp = ARM_AM::lsl;
1125   switch (type) {
1126     case 0:
1127       ShOp = ARM_AM::lsl;
1128       break;
1129     case 1:
1130       ShOp = ARM_AM::lsr;
1131       break;
1132     case 2:
1133       ShOp = ARM_AM::asr;
1134       break;
1135     case 3:
1136       ShOp = ARM_AM::ror;
1137       break;
1138   }
1139 
1140   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
1141   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))) return MCDisassembler::Fail;
1142   unsigned shift;
1143   if (U)
1144     shift = ARM_AM::getAM2Opc(ARM_AM::add, imm, ShOp);
1145   else
1146     shift = ARM_AM::getAM2Opc(ARM_AM::sub, imm, ShOp);
1147   Inst.addOperand(MCOperand::CreateImm(shift));
1148 
1149   return S;
1150 }
1151 
1152 static MCDisassembler::DecodeStatus
1153 DecodeAddrMode3Instruction(llvm::MCInst &Inst, unsigned Insn,
1154                            uint64_t Address, const void *Decoder) {
1155   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
1156 
1157   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
1158   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1159   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1160   unsigned type = fieldFromInstruction32(Insn, 22, 1);
1161   unsigned imm = fieldFromInstruction32(Insn, 8, 4);
1162   unsigned U = ((~fieldFromInstruction32(Insn, 23, 1)) & 1) << 8;
1163   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1164   unsigned W = fieldFromInstruction32(Insn, 21, 1);
1165   unsigned P = fieldFromInstruction32(Insn, 24, 1);
1166 
1167   bool writeback = (W == 1) | (P == 0);
1168 
1169   // For {LD,ST}RD, Rt must be even, else undefined.
1170   switch (Inst.getOpcode()) {
1171     case ARM::STRD:
1172     case ARM::STRD_PRE:
1173     case ARM::STRD_POST:
1174     case ARM::LDRD:
1175     case ARM::LDRD_PRE:
1176     case ARM::LDRD_POST:
1177       if (Rt & 0x1) return MCDisassembler::Fail;
1178       break;
1179   default:
1180     break;
1181   }
1182 
1183   if (writeback) { // Writeback
1184     if (P)
1185       U |= ARMII::IndexModePre << 9;
1186     else
1187       U |= ARMII::IndexModePost << 9;
1188 
1189     // On stores, the writeback operand precedes Rt.
1190     switch (Inst.getOpcode()) {
1191     case ARM::STRD:
1192     case ARM::STRD_PRE:
1193     case ARM::STRD_POST:
1194     case ARM::STRH:
1195     case ARM::STRH_PRE:
1196     case ARM::STRH_POST:
1197       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
1198       break;
1199     default:
1200       break;
1201     }
1202   }
1203 
1204   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder))) return MCDisassembler::Fail;
1205   switch (Inst.getOpcode()) {
1206     case ARM::STRD:
1207     case ARM::STRD_PRE:
1208     case ARM::STRD_POST:
1209     case ARM::LDRD:
1210     case ARM::LDRD_PRE:
1211     case ARM::LDRD_POST:
1212       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder))) return MCDisassembler::Fail;
1213       break;
1214     default:
1215       break;
1216   }
1217 
1218   if (writeback) {
1219     // On loads, the writeback operand comes after Rt.
1220     switch (Inst.getOpcode()) {
1221     case ARM::LDRD:
1222     case ARM::LDRD_PRE:
1223     case ARM::LDRD_POST:
1224     case ARM::LDRH:
1225     case ARM::LDRH_PRE:
1226     case ARM::LDRH_POST:
1227     case ARM::LDRSH:
1228     case ARM::LDRSH_PRE:
1229     case ARM::LDRSH_POST:
1230     case ARM::LDRSB:
1231     case ARM::LDRSB_PRE:
1232     case ARM::LDRSB_POST:
1233     case ARM::LDRHTr:
1234     case ARM::LDRSBTr:
1235       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
1236       break;
1237     default:
1238       break;
1239     }
1240   }
1241 
1242   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
1243 
1244   if (type) {
1245     Inst.addOperand(MCOperand::CreateReg(0));
1246     Inst.addOperand(MCOperand::CreateImm(U | (imm << 4) | Rm));
1247   } else {
1248     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))) return MCDisassembler::Fail;
1249     Inst.addOperand(MCOperand::CreateImm(U));
1250   }
1251 
1252   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder))) return MCDisassembler::Fail;
1253 
1254   return S;
1255 }
1256 
1257 static MCDisassembler::DecodeStatus DecodeRFEInstruction(llvm::MCInst &Inst, unsigned Insn,
1258                                  uint64_t Address, const void *Decoder) {
1259   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
1260 
1261   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1262   unsigned mode = fieldFromInstruction32(Insn, 23, 2);
1263 
1264   switch (mode) {
1265     case 0:
1266       mode = ARM_AM::da;
1267       break;
1268     case 1:
1269       mode = ARM_AM::ia;
1270       break;
1271     case 2:
1272       mode = ARM_AM::db;
1273       break;
1274     case 3:
1275       mode = ARM_AM::ib;
1276       break;
1277   }
1278 
1279   Inst.addOperand(MCOperand::CreateImm(mode));
1280   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
1281 
1282   return S;
1283 }
1284 
1285 static MCDisassembler::DecodeStatus DecodeMemMultipleWritebackInstruction(llvm::MCInst &Inst,
1286                                   unsigned Insn,
1287                                   uint64_t Address, const void *Decoder) {
1288   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
1289 
1290   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1291   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1292   unsigned reglist = fieldFromInstruction32(Insn, 0, 16);
1293 
1294   if (pred == 0xF) {
1295     switch (Inst.getOpcode()) {
1296       case ARM::LDMDA:
1297         Inst.setOpcode(ARM::RFEDA);
1298         break;
1299       case ARM::LDMDA_UPD:
1300         Inst.setOpcode(ARM::RFEDA_UPD);
1301         break;
1302       case ARM::LDMDB:
1303         Inst.setOpcode(ARM::RFEDB);
1304         break;
1305       case ARM::LDMDB_UPD:
1306         Inst.setOpcode(ARM::RFEDB_UPD);
1307         break;
1308       case ARM::LDMIA:
1309         Inst.setOpcode(ARM::RFEIA);
1310         break;
1311       case ARM::LDMIA_UPD:
1312         Inst.setOpcode(ARM::RFEIA_UPD);
1313         break;
1314       case ARM::LDMIB:
1315         Inst.setOpcode(ARM::RFEIB);
1316         break;
1317       case ARM::LDMIB_UPD:
1318         Inst.setOpcode(ARM::RFEIB_UPD);
1319         break;
1320       case ARM::STMDA:
1321         Inst.setOpcode(ARM::SRSDA);
1322         break;
1323       case ARM::STMDA_UPD:
1324         Inst.setOpcode(ARM::SRSDA_UPD);
1325         break;
1326       case ARM::STMDB:
1327         Inst.setOpcode(ARM::SRSDB);
1328         break;
1329       case ARM::STMDB_UPD:
1330         Inst.setOpcode(ARM::SRSDB_UPD);
1331         break;
1332       case ARM::STMIA:
1333         Inst.setOpcode(ARM::SRSIA);
1334         break;
1335       case ARM::STMIA_UPD:
1336         Inst.setOpcode(ARM::SRSIA_UPD);
1337         break;
1338       case ARM::STMIB:
1339         Inst.setOpcode(ARM::SRSIB);
1340         break;
1341       case ARM::STMIB_UPD:
1342         Inst.setOpcode(ARM::SRSIB_UPD);
1343         break;
1344       default:
1345         if (!Check(S, MCDisassembler::Fail)) return MCDisassembler::Fail;
1346     }
1347 
1348     // For stores (which become SRS's, the only operand is the mode.
1349     if (fieldFromInstruction32(Insn, 20, 1) == 0) {
1350       Inst.addOperand(
1351           MCOperand::CreateImm(fieldFromInstruction32(Insn, 0, 4)));
1352       return S;
1353     }
1354 
1355     return DecodeRFEInstruction(Inst, Insn, Address, Decoder);
1356   }
1357 
1358   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
1359   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail; // Tied
1360   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder))) return MCDisassembler::Fail;
1361   if (!Check(S, DecodeRegListOperand(Inst, reglist, Address, Decoder))) return MCDisassembler::Fail;
1362 
1363   return S;
1364 }
1365 
1366 static MCDisassembler::DecodeStatus DecodeCPSInstruction(llvm::MCInst &Inst, unsigned Insn,
1367                                  uint64_t Address, const void *Decoder) {
1368   unsigned imod = fieldFromInstruction32(Insn, 18, 2);
1369   unsigned M = fieldFromInstruction32(Insn, 17, 1);
1370   unsigned iflags = fieldFromInstruction32(Insn, 6, 3);
1371   unsigned mode = fieldFromInstruction32(Insn, 0, 5);
1372 
1373   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
1374 
1375   // imod == '01' --> UNPREDICTABLE
1376   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
1377   // return failure here.  The '01' imod value is unprintable, so there's
1378   // nothing useful we could do even if we returned UNPREDICTABLE.
1379 
1380   if (imod == 1) return MCDisassembler::Fail;
1381 
1382   if (imod && M) {
1383     Inst.setOpcode(ARM::CPS3p);
1384     Inst.addOperand(MCOperand::CreateImm(imod));
1385     Inst.addOperand(MCOperand::CreateImm(iflags));
1386     Inst.addOperand(MCOperand::CreateImm(mode));
1387   } else if (imod && !M) {
1388     Inst.setOpcode(ARM::CPS2p);
1389     Inst.addOperand(MCOperand::CreateImm(imod));
1390     Inst.addOperand(MCOperand::CreateImm(iflags));
1391     if (mode) S = MCDisassembler::SoftFail;
1392   } else if (!imod && M) {
1393     Inst.setOpcode(ARM::CPS1p);
1394     Inst.addOperand(MCOperand::CreateImm(mode));
1395     if (iflags) S = MCDisassembler::SoftFail;
1396   } else {
1397     // imod == '00' && M == '0' --> UNPREDICTABLE
1398     Inst.setOpcode(ARM::CPS1p);
1399     Inst.addOperand(MCOperand::CreateImm(mode));
1400     S = MCDisassembler::SoftFail;
1401   }
1402 
1403   return S;
1404 }
1405 
1406 static MCDisassembler::DecodeStatus DecodeT2CPSInstruction(llvm::MCInst &Inst, unsigned Insn,
1407                                  uint64_t Address, const void *Decoder) {
1408   unsigned imod = fieldFromInstruction32(Insn, 9, 2);
1409   unsigned M = fieldFromInstruction32(Insn, 8, 1);
1410   unsigned iflags = fieldFromInstruction32(Insn, 5, 3);
1411   unsigned mode = fieldFromInstruction32(Insn, 0, 5);
1412 
1413   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
1414 
1415   // imod == '01' --> UNPREDICTABLE
1416   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
1417   // return failure here.  The '01' imod value is unprintable, so there's
1418   // nothing useful we could do even if we returned UNPREDICTABLE.
1419 
1420   if (imod == 1) return MCDisassembler::Fail;
1421 
1422   if (imod && M) {
1423     Inst.setOpcode(ARM::t2CPS3p);
1424     Inst.addOperand(MCOperand::CreateImm(imod));
1425     Inst.addOperand(MCOperand::CreateImm(iflags));
1426     Inst.addOperand(MCOperand::CreateImm(mode));
1427   } else if (imod && !M) {
1428     Inst.setOpcode(ARM::t2CPS2p);
1429     Inst.addOperand(MCOperand::CreateImm(imod));
1430     Inst.addOperand(MCOperand::CreateImm(iflags));
1431     if (mode) S = MCDisassembler::SoftFail;
1432   } else if (!imod && M) {
1433     Inst.setOpcode(ARM::t2CPS1p);
1434     Inst.addOperand(MCOperand::CreateImm(mode));
1435     if (iflags) S = MCDisassembler::SoftFail;
1436   } else {
1437     // imod == '00' && M == '0' --> UNPREDICTABLE
1438     Inst.setOpcode(ARM::t2CPS1p);
1439     Inst.addOperand(MCOperand::CreateImm(mode));
1440     S = MCDisassembler::SoftFail;
1441   }
1442 
1443   return S;
1444 }
1445 
1446 
1447 static MCDisassembler::DecodeStatus DecodeSMLAInstruction(llvm::MCInst &Inst, unsigned Insn,
1448                                  uint64_t Address, const void *Decoder) {
1449   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
1450 
1451   unsigned Rd = fieldFromInstruction32(Insn, 16, 4);
1452   unsigned Rn = fieldFromInstruction32(Insn, 0, 4);
1453   unsigned Rm = fieldFromInstruction32(Insn, 8, 4);
1454   unsigned Ra = fieldFromInstruction32(Insn, 12, 4);
1455   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1456 
1457   if (pred == 0xF)
1458     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
1459 
1460   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder))) return MCDisassembler::Fail;
1461   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
1462   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder))) return MCDisassembler::Fail;
1463   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Ra, Address, Decoder))) return MCDisassembler::Fail;
1464 
1465   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder))) return MCDisassembler::Fail;
1466 
1467   return S;
1468 }
1469 
1470 static MCDisassembler::DecodeStatus DecodeAddrModeImm12Operand(llvm::MCInst &Inst, unsigned Val,
1471                            uint64_t Address, const void *Decoder) {
1472   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
1473 
1474   unsigned add = fieldFromInstruction32(Val, 12, 1);
1475   unsigned imm = fieldFromInstruction32(Val, 0, 12);
1476   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
1477 
1478   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
1479 
1480   if (!add) imm *= -1;
1481   if (imm == 0 && !add) imm = INT32_MIN;
1482   Inst.addOperand(MCOperand::CreateImm(imm));
1483 
1484   return S;
1485 }
1486 
1487 static MCDisassembler::DecodeStatus DecodeAddrMode5Operand(llvm::MCInst &Inst, unsigned Val,
1488                                    uint64_t Address, const void *Decoder) {
1489   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
1490 
1491   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
1492   unsigned U = fieldFromInstruction32(Val, 8, 1);
1493   unsigned imm = fieldFromInstruction32(Val, 0, 8);
1494 
1495   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
1496 
1497   if (U)
1498     Inst.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(ARM_AM::add, imm)));
1499   else
1500     Inst.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(ARM_AM::sub, imm)));
1501 
1502   return S;
1503 }
1504 
1505 static MCDisassembler::DecodeStatus DecodeAddrMode7Operand(llvm::MCInst &Inst, unsigned Val,
1506                                    uint64_t Address, const void *Decoder) {
1507   return DecodeGPRRegisterClass(Inst, Val, Address, Decoder);
1508 }
1509 
1510 static MCDisassembler::DecodeStatus
1511 DecodeBranchImmInstruction(llvm::MCInst &Inst, unsigned Insn,
1512                            uint64_t Address, const void *Decoder) {
1513   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
1514 
1515   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
1516   unsigned imm = fieldFromInstruction32(Insn, 0, 24) << 2;
1517 
1518   if (pred == 0xF) {
1519     Inst.setOpcode(ARM::BLXi);
1520     imm |= fieldFromInstruction32(Insn, 24, 1) << 1;
1521     Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(imm)));
1522     return S;
1523   }
1524 
1525   Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(imm)));
1526   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder))) return MCDisassembler::Fail;
1527 
1528   return S;
1529 }
1530 
1531 
1532 static MCDisassembler::DecodeStatus DecodeVCVTImmOperand(llvm::MCInst &Inst, unsigned Val,
1533                                  uint64_t Address, const void *Decoder) {
1534   Inst.addOperand(MCOperand::CreateImm(64 - Val));
1535   return MCDisassembler::Success;
1536 }
1537 
1538 static MCDisassembler::DecodeStatus DecodeAddrMode6Operand(llvm::MCInst &Inst, unsigned Val,
1539                                    uint64_t Address, const void *Decoder) {
1540   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
1541 
1542   unsigned Rm = fieldFromInstruction32(Val, 0, 4);
1543   unsigned align = fieldFromInstruction32(Val, 4, 2);
1544 
1545   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))) return MCDisassembler::Fail;
1546   if (!align)
1547     Inst.addOperand(MCOperand::CreateImm(0));
1548   else
1549     Inst.addOperand(MCOperand::CreateImm(4 << align));
1550 
1551   return S;
1552 }
1553 
1554 static MCDisassembler::DecodeStatus DecodeVLDInstruction(llvm::MCInst &Inst, unsigned Insn,
1555                                    uint64_t Address, const void *Decoder) {
1556   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
1557 
1558   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
1559   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
1560   unsigned wb = fieldFromInstruction32(Insn, 16, 4);
1561   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1562   Rn |= fieldFromInstruction32(Insn, 4, 2) << 4;
1563   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1564 
1565   // First output register
1566   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder))) return MCDisassembler::Fail;
1567 
1568   // Second output register
1569   switch (Inst.getOpcode()) {
1570     case ARM::VLD1q8:
1571     case ARM::VLD1q16:
1572     case ARM::VLD1q32:
1573     case ARM::VLD1q64:
1574     case ARM::VLD1q8_UPD:
1575     case ARM::VLD1q16_UPD:
1576     case ARM::VLD1q32_UPD:
1577     case ARM::VLD1q64_UPD:
1578     case ARM::VLD1d8T:
1579     case ARM::VLD1d16T:
1580     case ARM::VLD1d32T:
1581     case ARM::VLD1d64T:
1582     case ARM::VLD1d8T_UPD:
1583     case ARM::VLD1d16T_UPD:
1584     case ARM::VLD1d32T_UPD:
1585     case ARM::VLD1d64T_UPD:
1586     case ARM::VLD1d8Q:
1587     case ARM::VLD1d16Q:
1588     case ARM::VLD1d32Q:
1589     case ARM::VLD1d64Q:
1590     case ARM::VLD1d8Q_UPD:
1591     case ARM::VLD1d16Q_UPD:
1592     case ARM::VLD1d32Q_UPD:
1593     case ARM::VLD1d64Q_UPD:
1594     case ARM::VLD2d8:
1595     case ARM::VLD2d16:
1596     case ARM::VLD2d32:
1597     case ARM::VLD2d8_UPD:
1598     case ARM::VLD2d16_UPD:
1599     case ARM::VLD2d32_UPD:
1600     case ARM::VLD2q8:
1601     case ARM::VLD2q16:
1602     case ARM::VLD2q32:
1603     case ARM::VLD2q8_UPD:
1604     case ARM::VLD2q16_UPD:
1605     case ARM::VLD2q32_UPD:
1606     case ARM::VLD3d8:
1607     case ARM::VLD3d16:
1608     case ARM::VLD3d32:
1609     case ARM::VLD3d8_UPD:
1610     case ARM::VLD3d16_UPD:
1611     case ARM::VLD3d32_UPD:
1612     case ARM::VLD4d8:
1613     case ARM::VLD4d16:
1614     case ARM::VLD4d32:
1615     case ARM::VLD4d8_UPD:
1616     case ARM::VLD4d16_UPD:
1617     case ARM::VLD4d32_UPD:
1618       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder))) return MCDisassembler::Fail;
1619       break;
1620     case ARM::VLD2b8:
1621     case ARM::VLD2b16:
1622     case ARM::VLD2b32:
1623     case ARM::VLD2b8_UPD:
1624     case ARM::VLD2b16_UPD:
1625     case ARM::VLD2b32_UPD:
1626     case ARM::VLD3q8:
1627     case ARM::VLD3q16:
1628     case ARM::VLD3q32:
1629     case ARM::VLD3q8_UPD:
1630     case ARM::VLD3q16_UPD:
1631     case ARM::VLD3q32_UPD:
1632     case ARM::VLD4q8:
1633     case ARM::VLD4q16:
1634     case ARM::VLD4q32:
1635     case ARM::VLD4q8_UPD:
1636     case ARM::VLD4q16_UPD:
1637     case ARM::VLD4q32_UPD:
1638       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder))) return MCDisassembler::Fail;
1639     default:
1640       break;
1641   }
1642 
1643   // Third output register
1644   switch(Inst.getOpcode()) {
1645     case ARM::VLD1d8T:
1646     case ARM::VLD1d16T:
1647     case ARM::VLD1d32T:
1648     case ARM::VLD1d64T:
1649     case ARM::VLD1d8T_UPD:
1650     case ARM::VLD1d16T_UPD:
1651     case ARM::VLD1d32T_UPD:
1652     case ARM::VLD1d64T_UPD:
1653     case ARM::VLD1d8Q:
1654     case ARM::VLD1d16Q:
1655     case ARM::VLD1d32Q:
1656     case ARM::VLD1d64Q:
1657     case ARM::VLD1d8Q_UPD:
1658     case ARM::VLD1d16Q_UPD:
1659     case ARM::VLD1d32Q_UPD:
1660     case ARM::VLD1d64Q_UPD:
1661     case ARM::VLD2q8:
1662     case ARM::VLD2q16:
1663     case ARM::VLD2q32:
1664     case ARM::VLD2q8_UPD:
1665     case ARM::VLD2q16_UPD:
1666     case ARM::VLD2q32_UPD:
1667     case ARM::VLD3d8:
1668     case ARM::VLD3d16:
1669     case ARM::VLD3d32:
1670     case ARM::VLD3d8_UPD:
1671     case ARM::VLD3d16_UPD:
1672     case ARM::VLD3d32_UPD:
1673     case ARM::VLD4d8:
1674     case ARM::VLD4d16:
1675     case ARM::VLD4d32:
1676     case ARM::VLD4d8_UPD:
1677     case ARM::VLD4d16_UPD:
1678     case ARM::VLD4d32_UPD:
1679       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder))) return MCDisassembler::Fail;
1680       break;
1681     case ARM::VLD3q8:
1682     case ARM::VLD3q16:
1683     case ARM::VLD3q32:
1684     case ARM::VLD3q8_UPD:
1685     case ARM::VLD3q16_UPD:
1686     case ARM::VLD3q32_UPD:
1687     case ARM::VLD4q8:
1688     case ARM::VLD4q16:
1689     case ARM::VLD4q32:
1690     case ARM::VLD4q8_UPD:
1691     case ARM::VLD4q16_UPD:
1692     case ARM::VLD4q32_UPD:
1693       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder))) return MCDisassembler::Fail;
1694       break;
1695     default:
1696       break;
1697   }
1698 
1699   // Fourth output register
1700   switch (Inst.getOpcode()) {
1701     case ARM::VLD1d8Q:
1702     case ARM::VLD1d16Q:
1703     case ARM::VLD1d32Q:
1704     case ARM::VLD1d64Q:
1705     case ARM::VLD1d8Q_UPD:
1706     case ARM::VLD1d16Q_UPD:
1707     case ARM::VLD1d32Q_UPD:
1708     case ARM::VLD1d64Q_UPD:
1709     case ARM::VLD2q8:
1710     case ARM::VLD2q16:
1711     case ARM::VLD2q32:
1712     case ARM::VLD2q8_UPD:
1713     case ARM::VLD2q16_UPD:
1714     case ARM::VLD2q32_UPD:
1715     case ARM::VLD4d8:
1716     case ARM::VLD4d16:
1717     case ARM::VLD4d32:
1718     case ARM::VLD4d8_UPD:
1719     case ARM::VLD4d16_UPD:
1720     case ARM::VLD4d32_UPD:
1721       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder))) return MCDisassembler::Fail;
1722       break;
1723     case ARM::VLD4q8:
1724     case ARM::VLD4q16:
1725     case ARM::VLD4q32:
1726     case ARM::VLD4q8_UPD:
1727     case ARM::VLD4q16_UPD:
1728     case ARM::VLD4q32_UPD:
1729       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder))) return MCDisassembler::Fail;
1730       break;
1731     default:
1732       break;
1733   }
1734 
1735   // Writeback operand
1736   switch (Inst.getOpcode()) {
1737     case ARM::VLD1d8_UPD:
1738     case ARM::VLD1d16_UPD:
1739     case ARM::VLD1d32_UPD:
1740     case ARM::VLD1d64_UPD:
1741     case ARM::VLD1q8_UPD:
1742     case ARM::VLD1q16_UPD:
1743     case ARM::VLD1q32_UPD:
1744     case ARM::VLD1q64_UPD:
1745     case ARM::VLD1d8T_UPD:
1746     case ARM::VLD1d16T_UPD:
1747     case ARM::VLD1d32T_UPD:
1748     case ARM::VLD1d64T_UPD:
1749     case ARM::VLD1d8Q_UPD:
1750     case ARM::VLD1d16Q_UPD:
1751     case ARM::VLD1d32Q_UPD:
1752     case ARM::VLD1d64Q_UPD:
1753     case ARM::VLD2d8_UPD:
1754     case ARM::VLD2d16_UPD:
1755     case ARM::VLD2d32_UPD:
1756     case ARM::VLD2q8_UPD:
1757     case ARM::VLD2q16_UPD:
1758     case ARM::VLD2q32_UPD:
1759     case ARM::VLD2b8_UPD:
1760     case ARM::VLD2b16_UPD:
1761     case ARM::VLD2b32_UPD:
1762     case ARM::VLD3d8_UPD:
1763     case ARM::VLD3d16_UPD:
1764     case ARM::VLD3d32_UPD:
1765     case ARM::VLD3q8_UPD:
1766     case ARM::VLD3q16_UPD:
1767     case ARM::VLD3q32_UPD:
1768     case ARM::VLD4d8_UPD:
1769     case ARM::VLD4d16_UPD:
1770     case ARM::VLD4d32_UPD:
1771     case ARM::VLD4q8_UPD:
1772     case ARM::VLD4q16_UPD:
1773     case ARM::VLD4q32_UPD:
1774       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder))) return MCDisassembler::Fail;
1775       break;
1776     default:
1777       break;
1778   }
1779 
1780   // AddrMode6 Base (register+alignment)
1781   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
1782 
1783   // AddrMode6 Offset (register)
1784   if (Rm == 0xD)
1785     Inst.addOperand(MCOperand::CreateReg(0));
1786   else if (Rm != 0xF) {
1787     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))) return MCDisassembler::Fail;
1788   }
1789 
1790   return S;
1791 }
1792 
1793 static MCDisassembler::DecodeStatus DecodeVSTInstruction(llvm::MCInst &Inst, unsigned Insn,
1794                                  uint64_t Address, const void *Decoder) {
1795   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
1796 
1797   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
1798   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
1799   unsigned wb = fieldFromInstruction32(Insn, 16, 4);
1800   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
1801   Rn |= fieldFromInstruction32(Insn, 4, 2) << 4;
1802   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
1803 
1804   // Writeback Operand
1805   switch (Inst.getOpcode()) {
1806     case ARM::VST1d8_UPD:
1807     case ARM::VST1d16_UPD:
1808     case ARM::VST1d32_UPD:
1809     case ARM::VST1d64_UPD:
1810     case ARM::VST1q8_UPD:
1811     case ARM::VST1q16_UPD:
1812     case ARM::VST1q32_UPD:
1813     case ARM::VST1q64_UPD:
1814     case ARM::VST1d8T_UPD:
1815     case ARM::VST1d16T_UPD:
1816     case ARM::VST1d32T_UPD:
1817     case ARM::VST1d64T_UPD:
1818     case ARM::VST1d8Q_UPD:
1819     case ARM::VST1d16Q_UPD:
1820     case ARM::VST1d32Q_UPD:
1821     case ARM::VST1d64Q_UPD:
1822     case ARM::VST2d8_UPD:
1823     case ARM::VST2d16_UPD:
1824     case ARM::VST2d32_UPD:
1825     case ARM::VST2q8_UPD:
1826     case ARM::VST2q16_UPD:
1827     case ARM::VST2q32_UPD:
1828     case ARM::VST2b8_UPD:
1829     case ARM::VST2b16_UPD:
1830     case ARM::VST2b32_UPD:
1831     case ARM::VST3d8_UPD:
1832     case ARM::VST3d16_UPD:
1833     case ARM::VST3d32_UPD:
1834     case ARM::VST3q8_UPD:
1835     case ARM::VST3q16_UPD:
1836     case ARM::VST3q32_UPD:
1837     case ARM::VST4d8_UPD:
1838     case ARM::VST4d16_UPD:
1839     case ARM::VST4d32_UPD:
1840     case ARM::VST4q8_UPD:
1841     case ARM::VST4q16_UPD:
1842     case ARM::VST4q32_UPD:
1843       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder))) return MCDisassembler::Fail;
1844       break;
1845     default:
1846       break;
1847   }
1848 
1849   // AddrMode6 Base (register+alignment)
1850   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
1851 
1852   // AddrMode6 Offset (register)
1853   if (Rm == 0xD)
1854     Inst.addOperand(MCOperand::CreateReg(0));
1855   else if (Rm != 0xF) {
1856     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))) return MCDisassembler::Fail;
1857   }
1858 
1859   // First input register
1860   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder))) return MCDisassembler::Fail;
1861 
1862   // Second input register
1863   switch (Inst.getOpcode()) {
1864     case ARM::VST1q8:
1865     case ARM::VST1q16:
1866     case ARM::VST1q32:
1867     case ARM::VST1q64:
1868     case ARM::VST1q8_UPD:
1869     case ARM::VST1q16_UPD:
1870     case ARM::VST1q32_UPD:
1871     case ARM::VST1q64_UPD:
1872     case ARM::VST1d8T:
1873     case ARM::VST1d16T:
1874     case ARM::VST1d32T:
1875     case ARM::VST1d64T:
1876     case ARM::VST1d8T_UPD:
1877     case ARM::VST1d16T_UPD:
1878     case ARM::VST1d32T_UPD:
1879     case ARM::VST1d64T_UPD:
1880     case ARM::VST1d8Q:
1881     case ARM::VST1d16Q:
1882     case ARM::VST1d32Q:
1883     case ARM::VST1d64Q:
1884     case ARM::VST1d8Q_UPD:
1885     case ARM::VST1d16Q_UPD:
1886     case ARM::VST1d32Q_UPD:
1887     case ARM::VST1d64Q_UPD:
1888     case ARM::VST2d8:
1889     case ARM::VST2d16:
1890     case ARM::VST2d32:
1891     case ARM::VST2d8_UPD:
1892     case ARM::VST2d16_UPD:
1893     case ARM::VST2d32_UPD:
1894     case ARM::VST2q8:
1895     case ARM::VST2q16:
1896     case ARM::VST2q32:
1897     case ARM::VST2q8_UPD:
1898     case ARM::VST2q16_UPD:
1899     case ARM::VST2q32_UPD:
1900     case ARM::VST3d8:
1901     case ARM::VST3d16:
1902     case ARM::VST3d32:
1903     case ARM::VST3d8_UPD:
1904     case ARM::VST3d16_UPD:
1905     case ARM::VST3d32_UPD:
1906     case ARM::VST4d8:
1907     case ARM::VST4d16:
1908     case ARM::VST4d32:
1909     case ARM::VST4d8_UPD:
1910     case ARM::VST4d16_UPD:
1911     case ARM::VST4d32_UPD:
1912       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder))) return MCDisassembler::Fail;
1913       break;
1914     case ARM::VST2b8:
1915     case ARM::VST2b16:
1916     case ARM::VST2b32:
1917     case ARM::VST2b8_UPD:
1918     case ARM::VST2b16_UPD:
1919     case ARM::VST2b32_UPD:
1920     case ARM::VST3q8:
1921     case ARM::VST3q16:
1922     case ARM::VST3q32:
1923     case ARM::VST3q8_UPD:
1924     case ARM::VST3q16_UPD:
1925     case ARM::VST3q32_UPD:
1926     case ARM::VST4q8:
1927     case ARM::VST4q16:
1928     case ARM::VST4q32:
1929     case ARM::VST4q8_UPD:
1930     case ARM::VST4q16_UPD:
1931     case ARM::VST4q32_UPD:
1932       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder))) return MCDisassembler::Fail;
1933       break;
1934     default:
1935       break;
1936   }
1937 
1938   // Third input register
1939   switch (Inst.getOpcode()) {
1940     case ARM::VST1d8T:
1941     case ARM::VST1d16T:
1942     case ARM::VST1d32T:
1943     case ARM::VST1d64T:
1944     case ARM::VST1d8T_UPD:
1945     case ARM::VST1d16T_UPD:
1946     case ARM::VST1d32T_UPD:
1947     case ARM::VST1d64T_UPD:
1948     case ARM::VST1d8Q:
1949     case ARM::VST1d16Q:
1950     case ARM::VST1d32Q:
1951     case ARM::VST1d64Q:
1952     case ARM::VST1d8Q_UPD:
1953     case ARM::VST1d16Q_UPD:
1954     case ARM::VST1d32Q_UPD:
1955     case ARM::VST1d64Q_UPD:
1956     case ARM::VST2q8:
1957     case ARM::VST2q16:
1958     case ARM::VST2q32:
1959     case ARM::VST2q8_UPD:
1960     case ARM::VST2q16_UPD:
1961     case ARM::VST2q32_UPD:
1962     case ARM::VST3d8:
1963     case ARM::VST3d16:
1964     case ARM::VST3d32:
1965     case ARM::VST3d8_UPD:
1966     case ARM::VST3d16_UPD:
1967     case ARM::VST3d32_UPD:
1968     case ARM::VST4d8:
1969     case ARM::VST4d16:
1970     case ARM::VST4d32:
1971     case ARM::VST4d8_UPD:
1972     case ARM::VST4d16_UPD:
1973     case ARM::VST4d32_UPD:
1974       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder))) return MCDisassembler::Fail;
1975       break;
1976     case ARM::VST3q8:
1977     case ARM::VST3q16:
1978     case ARM::VST3q32:
1979     case ARM::VST3q8_UPD:
1980     case ARM::VST3q16_UPD:
1981     case ARM::VST3q32_UPD:
1982     case ARM::VST4q8:
1983     case ARM::VST4q16:
1984     case ARM::VST4q32:
1985     case ARM::VST4q8_UPD:
1986     case ARM::VST4q16_UPD:
1987     case ARM::VST4q32_UPD:
1988       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder))) return MCDisassembler::Fail;
1989       break;
1990     default:
1991       break;
1992   }
1993 
1994   // Fourth input register
1995   switch (Inst.getOpcode()) {
1996     case ARM::VST1d8Q:
1997     case ARM::VST1d16Q:
1998     case ARM::VST1d32Q:
1999     case ARM::VST1d64Q:
2000     case ARM::VST1d8Q_UPD:
2001     case ARM::VST1d16Q_UPD:
2002     case ARM::VST1d32Q_UPD:
2003     case ARM::VST1d64Q_UPD:
2004     case ARM::VST2q8:
2005     case ARM::VST2q16:
2006     case ARM::VST2q32:
2007     case ARM::VST2q8_UPD:
2008     case ARM::VST2q16_UPD:
2009     case ARM::VST2q32_UPD:
2010     case ARM::VST4d8:
2011     case ARM::VST4d16:
2012     case ARM::VST4d32:
2013     case ARM::VST4d8_UPD:
2014     case ARM::VST4d16_UPD:
2015     case ARM::VST4d32_UPD:
2016       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder))) return MCDisassembler::Fail;
2017       break;
2018     case ARM::VST4q8:
2019     case ARM::VST4q16:
2020     case ARM::VST4q32:
2021     case ARM::VST4q8_UPD:
2022     case ARM::VST4q16_UPD:
2023     case ARM::VST4q32_UPD:
2024       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder))) return MCDisassembler::Fail;
2025       break;
2026     default:
2027       break;
2028   }
2029 
2030   return S;
2031 }
2032 
2033 static MCDisassembler::DecodeStatus DecodeVLD1DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2034                                     uint64_t Address, const void *Decoder) {
2035   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
2036 
2037   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2038   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2039   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2040   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2041   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2042   unsigned size = fieldFromInstruction32(Insn, 6, 2);
2043   unsigned regs = fieldFromInstruction32(Insn, 5, 1) + 1;
2044 
2045   align *= (1 << size);
2046 
2047   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder))) return MCDisassembler::Fail;
2048   if (regs == 2) {
2049     if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder))) return MCDisassembler::Fail;
2050   }
2051   if (Rm != 0xF) {
2052     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
2053   }
2054 
2055   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
2056   Inst.addOperand(MCOperand::CreateImm(align));
2057 
2058   if (Rm == 0xD)
2059     Inst.addOperand(MCOperand::CreateReg(0));
2060   else if (Rm != 0xF) {
2061     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))) return MCDisassembler::Fail;
2062   }
2063 
2064   return S;
2065 }
2066 
2067 static MCDisassembler::DecodeStatus DecodeVLD2DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2068                                     uint64_t Address, const void *Decoder) {
2069   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
2070 
2071   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2072   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2073   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2074   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2075   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2076   unsigned size = 1 << fieldFromInstruction32(Insn, 6, 2);
2077   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2078   align *= 2*size;
2079 
2080   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder))) return MCDisassembler::Fail;
2081   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder))) return MCDisassembler::Fail;
2082   if (Rm != 0xF) {
2083     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
2084   }
2085 
2086   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
2087   Inst.addOperand(MCOperand::CreateImm(align));
2088 
2089   if (Rm == 0xD)
2090     Inst.addOperand(MCOperand::CreateReg(0));
2091   else if (Rm != 0xF) {
2092     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))) return MCDisassembler::Fail;
2093   }
2094 
2095   return S;
2096 }
2097 
2098 static MCDisassembler::DecodeStatus DecodeVLD3DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2099                                     uint64_t Address, const void *Decoder) {
2100   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
2101 
2102   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2103   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2104   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2105   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2106   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2107 
2108   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder))) return MCDisassembler::Fail;
2109   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder))) return MCDisassembler::Fail;
2110   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder))) return MCDisassembler::Fail;
2111   if (Rm != 0xF) {
2112     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
2113   }
2114 
2115   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
2116   Inst.addOperand(MCOperand::CreateImm(0));
2117 
2118   if (Rm == 0xD)
2119     Inst.addOperand(MCOperand::CreateReg(0));
2120   else if (Rm != 0xF) {
2121     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))) return MCDisassembler::Fail;
2122   }
2123 
2124   return S;
2125 }
2126 
2127 static MCDisassembler::DecodeStatus DecodeVLD4DupInstruction(llvm::MCInst &Inst, unsigned Insn,
2128                                     uint64_t Address, const void *Decoder) {
2129   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
2130 
2131   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2132   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2133   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2134   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2135   unsigned size = fieldFromInstruction32(Insn, 6, 2);
2136   unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
2137   unsigned align = fieldFromInstruction32(Insn, 4, 1);
2138 
2139   if (size == 0x3) {
2140     size = 4;
2141     align = 16;
2142   } else {
2143     if (size == 2) {
2144       size = 1 << size;
2145       align *= 8;
2146     } else {
2147       size = 1 << size;
2148       align *= 4*size;
2149     }
2150   }
2151 
2152   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder))) return MCDisassembler::Fail;
2153   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder))) return MCDisassembler::Fail;
2154   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder))) return MCDisassembler::Fail;
2155   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3*inc)%32, Address, Decoder))) return MCDisassembler::Fail;
2156   if (Rm != 0xF) {
2157     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
2158   }
2159 
2160   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
2161   Inst.addOperand(MCOperand::CreateImm(align));
2162 
2163   if (Rm == 0xD)
2164     Inst.addOperand(MCOperand::CreateReg(0));
2165   else if (Rm != 0xF) {
2166     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))) return MCDisassembler::Fail;
2167   }
2168 
2169   return S;
2170 }
2171 
2172 static MCDisassembler::DecodeStatus
2173 DecodeNEONModImmInstruction(llvm::MCInst &Inst, unsigned Insn,
2174                             uint64_t Address, const void *Decoder) {
2175   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
2176 
2177   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2178   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2179   unsigned imm = fieldFromInstruction32(Insn, 0, 4);
2180   imm |= fieldFromInstruction32(Insn, 16, 3) << 4;
2181   imm |= fieldFromInstruction32(Insn, 24, 1) << 7;
2182   imm |= fieldFromInstruction32(Insn, 8, 4) << 8;
2183   imm |= fieldFromInstruction32(Insn, 5, 1) << 12;
2184   unsigned Q = fieldFromInstruction32(Insn, 6, 1);
2185 
2186   if (Q) {
2187     if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder))) return MCDisassembler::Fail;
2188   } else {
2189     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder))) return MCDisassembler::Fail;
2190   }
2191 
2192   Inst.addOperand(MCOperand::CreateImm(imm));
2193 
2194   switch (Inst.getOpcode()) {
2195     case ARM::VORRiv4i16:
2196     case ARM::VORRiv2i32:
2197     case ARM::VBICiv4i16:
2198     case ARM::VBICiv2i32:
2199       if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder))) return MCDisassembler::Fail;
2200       break;
2201     case ARM::VORRiv8i16:
2202     case ARM::VORRiv4i32:
2203     case ARM::VBICiv8i16:
2204     case ARM::VBICiv4i32:
2205       if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder))) return MCDisassembler::Fail;
2206       break;
2207     default:
2208       break;
2209   }
2210 
2211   return S;
2212 }
2213 
2214 static MCDisassembler::DecodeStatus DecodeVSHLMaxInstruction(llvm::MCInst &Inst, unsigned Insn,
2215                                         uint64_t Address, const void *Decoder) {
2216   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
2217 
2218   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2219   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2220   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2221   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
2222   unsigned size = fieldFromInstruction32(Insn, 18, 2);
2223 
2224   if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder))) return MCDisassembler::Fail;
2225   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder))) return MCDisassembler::Fail;
2226   Inst.addOperand(MCOperand::CreateImm(8 << size));
2227 
2228   return S;
2229 }
2230 
2231 static MCDisassembler::DecodeStatus DecodeShiftRight8Imm(llvm::MCInst &Inst, unsigned Val,
2232                                uint64_t Address, const void *Decoder) {
2233   Inst.addOperand(MCOperand::CreateImm(8 - Val));
2234   return MCDisassembler::Success;
2235 }
2236 
2237 static MCDisassembler::DecodeStatus DecodeShiftRight16Imm(llvm::MCInst &Inst, unsigned Val,
2238                                uint64_t Address, const void *Decoder) {
2239   Inst.addOperand(MCOperand::CreateImm(16 - Val));
2240   return MCDisassembler::Success;
2241 }
2242 
2243 static MCDisassembler::DecodeStatus DecodeShiftRight32Imm(llvm::MCInst &Inst, unsigned Val,
2244                                uint64_t Address, const void *Decoder) {
2245   Inst.addOperand(MCOperand::CreateImm(32 - Val));
2246   return MCDisassembler::Success;
2247 }
2248 
2249 static MCDisassembler::DecodeStatus DecodeShiftRight64Imm(llvm::MCInst &Inst, unsigned Val,
2250                                uint64_t Address, const void *Decoder) {
2251   Inst.addOperand(MCOperand::CreateImm(64 - Val));
2252   return MCDisassembler::Success;
2253 }
2254 
2255 static MCDisassembler::DecodeStatus DecodeTBLInstruction(llvm::MCInst &Inst, unsigned Insn,
2256                                uint64_t Address, const void *Decoder) {
2257   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
2258 
2259   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2260   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2261   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2262   Rn |= fieldFromInstruction32(Insn, 7, 1) << 4;
2263   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2264   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
2265   unsigned op = fieldFromInstruction32(Insn, 6, 1);
2266   unsigned length = fieldFromInstruction32(Insn, 8, 2) + 1;
2267 
2268   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder))) return MCDisassembler::Fail;
2269   if (op) {
2270     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder))) return MCDisassembler::Fail; // Writeback
2271   }
2272 
2273   for (unsigned i = 0; i < length; ++i) {
2274     if (!Check(S, DecodeDPRRegisterClass(Inst, (Rn+i)%32, Address, Decoder))) return MCDisassembler::Fail;
2275   }
2276 
2277   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder))) return MCDisassembler::Fail;
2278 
2279   return S;
2280 }
2281 
2282 static MCDisassembler::DecodeStatus DecodeVFPfpImm(llvm::MCInst &Inst, unsigned Val,
2283                             uint64_t Address, const void *Decoder) {
2284   // The immediate needs to be a fully instantiated float.  However, the
2285   // auto-generated decoder is only able to fill in some of the bits
2286   // necessary.  For instance, the 'b' bit is replicated multiple times,
2287   // and is even present in inverted form in one bit.  We do a little
2288   // binary parsing here to fill in those missing bits, and then
2289   // reinterpret it all as a float.
2290   union {
2291     uint32_t integer;
2292     float fp;
2293   } fp_conv;
2294 
2295   fp_conv.integer = Val;
2296   uint32_t b = fieldFromInstruction32(Val, 25, 1);
2297   fp_conv.integer |= b << 26;
2298   fp_conv.integer |= b << 27;
2299   fp_conv.integer |= b << 28;
2300   fp_conv.integer |= b << 29;
2301   fp_conv.integer |= (~b & 0x1) << 30;
2302 
2303   Inst.addOperand(MCOperand::CreateFPImm(fp_conv.fp));
2304   return MCDisassembler::Success;
2305 }
2306 
2307 static MCDisassembler::DecodeStatus DecodeThumbAddSpecialReg(llvm::MCInst &Inst, uint16_t Insn,
2308                                      uint64_t Address, const void *Decoder) {
2309   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
2310 
2311   unsigned dst = fieldFromInstruction16(Insn, 8, 3);
2312   unsigned imm = fieldFromInstruction16(Insn, 0, 8);
2313 
2314   if (!Check(S, DecodetGPRRegisterClass(Inst, dst, Address, Decoder))) return MCDisassembler::Fail;
2315 
2316   switch(Inst.getOpcode()) {
2317     default:
2318       return MCDisassembler::Fail;
2319     case ARM::tADR:
2320       break; // tADR does not explicitly represent the PC as an operand.
2321     case ARM::tADDrSPi:
2322       Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2323       break;
2324   }
2325 
2326   Inst.addOperand(MCOperand::CreateImm(imm));
2327   return S;
2328 }
2329 
2330 static MCDisassembler::DecodeStatus DecodeThumbBROperand(llvm::MCInst &Inst, unsigned Val,
2331                                  uint64_t Address, const void *Decoder) {
2332   Inst.addOperand(MCOperand::CreateImm(SignExtend32<12>(Val << 1)));
2333   return MCDisassembler::Success;
2334 }
2335 
2336 static MCDisassembler::DecodeStatus DecodeT2BROperand(llvm::MCInst &Inst, unsigned Val,
2337                                  uint64_t Address, const void *Decoder) {
2338   Inst.addOperand(MCOperand::CreateImm(SignExtend32<21>(Val)));
2339   return MCDisassembler::Success;
2340 }
2341 
2342 static MCDisassembler::DecodeStatus DecodeThumbCmpBROperand(llvm::MCInst &Inst, unsigned Val,
2343                                  uint64_t Address, const void *Decoder) {
2344   Inst.addOperand(MCOperand::CreateImm(SignExtend32<7>(Val << 1)));
2345   return MCDisassembler::Success;
2346 }
2347 
2348 static MCDisassembler::DecodeStatus DecodeThumbAddrModeRR(llvm::MCInst &Inst, unsigned Val,
2349                                  uint64_t Address, const void *Decoder) {
2350   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
2351 
2352   unsigned Rn = fieldFromInstruction32(Val, 0, 3);
2353   unsigned Rm = fieldFromInstruction32(Val, 3, 3);
2354 
2355   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
2356   if (!Check(S, DecodetGPRRegisterClass(Inst, Rm, Address, Decoder))) return MCDisassembler::Fail;
2357 
2358   return S;
2359 }
2360 
2361 static MCDisassembler::DecodeStatus DecodeThumbAddrModeIS(llvm::MCInst &Inst, unsigned Val,
2362                                   uint64_t Address, const void *Decoder) {
2363   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
2364 
2365   unsigned Rn = fieldFromInstruction32(Val, 0, 3);
2366   unsigned imm = fieldFromInstruction32(Val, 3, 5);
2367 
2368   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
2369   Inst.addOperand(MCOperand::CreateImm(imm));
2370 
2371   return S;
2372 }
2373 
2374 static MCDisassembler::DecodeStatus DecodeThumbAddrModePC(llvm::MCInst &Inst, unsigned Val,
2375                                   uint64_t Address, const void *Decoder) {
2376   Inst.addOperand(MCOperand::CreateImm(Val << 2));
2377 
2378   return MCDisassembler::Success;
2379 }
2380 
2381 static MCDisassembler::DecodeStatus DecodeThumbAddrModeSP(llvm::MCInst &Inst, unsigned Val,
2382                                   uint64_t Address, const void *Decoder) {
2383   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2384   Inst.addOperand(MCOperand::CreateImm(Val));
2385 
2386   return MCDisassembler::Success;
2387 }
2388 
2389 static MCDisassembler::DecodeStatus DecodeT2AddrModeSOReg(llvm::MCInst &Inst, unsigned Val,
2390                                   uint64_t Address, const void *Decoder) {
2391   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
2392 
2393   unsigned Rn = fieldFromInstruction32(Val, 6, 4);
2394   unsigned Rm = fieldFromInstruction32(Val, 2, 4);
2395   unsigned imm = fieldFromInstruction32(Val, 0, 2);
2396 
2397   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
2398   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder))) return MCDisassembler::Fail;
2399   Inst.addOperand(MCOperand::CreateImm(imm));
2400 
2401   return S;
2402 }
2403 
2404 static MCDisassembler::DecodeStatus DecodeT2LoadShift(llvm::MCInst &Inst, unsigned Insn,
2405                               uint64_t Address, const void *Decoder) {
2406   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
2407 
2408   switch (Inst.getOpcode()) {
2409     case ARM::t2PLDs:
2410     case ARM::t2PLDWs:
2411     case ARM::t2PLIs:
2412       break;
2413     default: {
2414       unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2415       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder))) return MCDisassembler::Fail;
2416     }
2417   }
2418 
2419   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2420   if (Rn == 0xF) {
2421     switch (Inst.getOpcode()) {
2422       case ARM::t2LDRBs:
2423         Inst.setOpcode(ARM::t2LDRBpci);
2424         break;
2425       case ARM::t2LDRHs:
2426         Inst.setOpcode(ARM::t2LDRHpci);
2427         break;
2428       case ARM::t2LDRSHs:
2429         Inst.setOpcode(ARM::t2LDRSHpci);
2430         break;
2431       case ARM::t2LDRSBs:
2432         Inst.setOpcode(ARM::t2LDRSBpci);
2433         break;
2434       case ARM::t2PLDs:
2435         Inst.setOpcode(ARM::t2PLDi12);
2436         Inst.addOperand(MCOperand::CreateReg(ARM::PC));
2437         break;
2438       default:
2439         return MCDisassembler::Fail;
2440     }
2441 
2442     int imm = fieldFromInstruction32(Insn, 0, 12);
2443     if (!fieldFromInstruction32(Insn, 23, 1)) imm *= -1;
2444     Inst.addOperand(MCOperand::CreateImm(imm));
2445 
2446     return S;
2447   }
2448 
2449   unsigned addrmode = fieldFromInstruction32(Insn, 4, 2);
2450   addrmode |= fieldFromInstruction32(Insn, 0, 4) << 2;
2451   addrmode |= fieldFromInstruction32(Insn, 16, 4) << 6;
2452   if (!Check(S, DecodeT2AddrModeSOReg(Inst, addrmode, Address, Decoder))) return MCDisassembler::Fail;
2453 
2454   return S;
2455 }
2456 
2457 static MCDisassembler::DecodeStatus DecodeT2Imm8S4(llvm::MCInst &Inst, unsigned Val,
2458                            uint64_t Address, const void *Decoder) {
2459   int imm = Val & 0xFF;
2460   if (!(Val & 0x100)) imm *= -1;
2461   Inst.addOperand(MCOperand::CreateImm(imm << 2));
2462 
2463   return MCDisassembler::Success;
2464 }
2465 
2466 static MCDisassembler::DecodeStatus DecodeT2AddrModeImm8s4(llvm::MCInst &Inst, unsigned Val,
2467                                    uint64_t Address, const void *Decoder) {
2468   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
2469 
2470   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
2471   unsigned imm = fieldFromInstruction32(Val, 0, 9);
2472 
2473   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
2474   if (!Check(S, DecodeT2Imm8S4(Inst, imm, Address, Decoder))) return MCDisassembler::Fail;
2475 
2476   return S;
2477 }
2478 
2479 static MCDisassembler::DecodeStatus DecodeT2Imm8(llvm::MCInst &Inst, unsigned Val,
2480                          uint64_t Address, const void *Decoder) {
2481   int imm = Val & 0xFF;
2482   if (!(Val & 0x100)) imm *= -1;
2483   Inst.addOperand(MCOperand::CreateImm(imm));
2484 
2485   return MCDisassembler::Success;
2486 }
2487 
2488 
2489 static MCDisassembler::DecodeStatus DecodeT2AddrModeImm8(llvm::MCInst &Inst, unsigned Val,
2490                                  uint64_t Address, const void *Decoder) {
2491   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
2492 
2493   unsigned Rn = fieldFromInstruction32(Val, 9, 4);
2494   unsigned imm = fieldFromInstruction32(Val, 0, 9);
2495 
2496   // Some instructions always use an additive offset.
2497   switch (Inst.getOpcode()) {
2498     case ARM::t2LDRT:
2499     case ARM::t2LDRBT:
2500     case ARM::t2LDRHT:
2501     case ARM::t2LDRSBT:
2502     case ARM::t2LDRSHT:
2503       imm |= 0x100;
2504       break;
2505     default:
2506       break;
2507   }
2508 
2509   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
2510   if (!Check(S, DecodeT2Imm8(Inst, imm, Address, Decoder))) return MCDisassembler::Fail;
2511 
2512   return S;
2513 }
2514 
2515 
2516 static MCDisassembler::DecodeStatus DecodeT2AddrModeImm12(llvm::MCInst &Inst, unsigned Val,
2517                                   uint64_t Address, const void *Decoder) {
2518   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
2519 
2520   unsigned Rn = fieldFromInstruction32(Val, 13, 4);
2521   unsigned imm = fieldFromInstruction32(Val, 0, 12);
2522 
2523   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
2524   Inst.addOperand(MCOperand::CreateImm(imm));
2525 
2526   return S;
2527 }
2528 
2529 
2530 static MCDisassembler::DecodeStatus DecodeThumbAddSPImm(llvm::MCInst &Inst, uint16_t Insn,
2531                                 uint64_t Address, const void *Decoder) {
2532   unsigned imm = fieldFromInstruction16(Insn, 0, 7);
2533 
2534   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2535   Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2536   Inst.addOperand(MCOperand::CreateImm(imm));
2537 
2538   return MCDisassembler::Success;
2539 }
2540 
2541 static MCDisassembler::DecodeStatus DecodeThumbAddSPReg(llvm::MCInst &Inst, uint16_t Insn,
2542                                 uint64_t Address, const void *Decoder) {
2543   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
2544 
2545   if (Inst.getOpcode() == ARM::tADDrSP) {
2546     unsigned Rdm = fieldFromInstruction16(Insn, 0, 3);
2547     Rdm |= fieldFromInstruction16(Insn, 7, 1) << 3;
2548 
2549     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder))) return MCDisassembler::Fail;
2550     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder))) return MCDisassembler::Fail;
2551     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2552   } else if (Inst.getOpcode() == ARM::tADDspr) {
2553     unsigned Rm = fieldFromInstruction16(Insn, 3, 4);
2554 
2555     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2556     Inst.addOperand(MCOperand::CreateReg(ARM::SP));
2557     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))) return MCDisassembler::Fail;
2558   }
2559 
2560   return S;
2561 }
2562 
2563 static MCDisassembler::DecodeStatus DecodeThumbCPS(llvm::MCInst &Inst, uint16_t Insn,
2564                            uint64_t Address, const void *Decoder) {
2565   unsigned imod = fieldFromInstruction16(Insn, 4, 1) | 0x2;
2566   unsigned flags = fieldFromInstruction16(Insn, 0, 3);
2567 
2568   Inst.addOperand(MCOperand::CreateImm(imod));
2569   Inst.addOperand(MCOperand::CreateImm(flags));
2570 
2571   return MCDisassembler::Success;
2572 }
2573 
2574 static MCDisassembler::DecodeStatus DecodePostIdxReg(llvm::MCInst &Inst, unsigned Insn,
2575                              uint64_t Address, const void *Decoder) {
2576   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
2577   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2578   unsigned add = fieldFromInstruction32(Insn, 4, 1);
2579 
2580   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))) return MCDisassembler::Fail;
2581   Inst.addOperand(MCOperand::CreateImm(add));
2582 
2583   return S;
2584 }
2585 
2586 static MCDisassembler::DecodeStatus DecodeThumbBLXOffset(llvm::MCInst &Inst, unsigned Val,
2587                                  uint64_t Address, const void *Decoder) {
2588   Inst.addOperand(MCOperand::CreateImm(SignExtend32<22>(Val << 1)));
2589   return MCDisassembler::Success;
2590 }
2591 
2592 static MCDisassembler::DecodeStatus DecodeCoprocessor(llvm::MCInst &Inst, unsigned Val,
2593                               uint64_t Address, const void *Decoder) {
2594   if (Val == 0xA || Val == 0xB)
2595     return MCDisassembler::Fail;
2596 
2597   Inst.addOperand(MCOperand::CreateImm(Val));
2598   return MCDisassembler::Success;
2599 }
2600 
2601 static MCDisassembler::DecodeStatus
2602 DecodeThumb2BCCInstruction(llvm::MCInst &Inst, unsigned Insn,
2603                            uint64_t Address, const void *Decoder) {
2604   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
2605 
2606   unsigned pred = fieldFromInstruction32(Insn, 22, 4);
2607   if (pred == 0xE || pred == 0xF) {
2608     unsigned opc = fieldFromInstruction32(Insn, 4, 28);
2609     switch (opc) {
2610       default:
2611         return MCDisassembler::Fail;
2612       case 0xf3bf8f4:
2613         Inst.setOpcode(ARM::t2DSB);
2614         break;
2615       case 0xf3bf8f5:
2616         Inst.setOpcode(ARM::t2DMB);
2617         break;
2618       case 0xf3bf8f6:
2619         Inst.setOpcode(ARM::t2ISB);
2620         return MCDisassembler::Success;
2621     }
2622 
2623     unsigned imm = fieldFromInstruction32(Insn, 0, 4);
2624     return DecodeMemBarrierOption(Inst, imm, Address, Decoder);
2625   }
2626 
2627   unsigned brtarget = fieldFromInstruction32(Insn, 0, 11) << 1;
2628   brtarget |= fieldFromInstruction32(Insn, 11, 1) << 19;
2629   brtarget |= fieldFromInstruction32(Insn, 13, 1) << 18;
2630   brtarget |= fieldFromInstruction32(Insn, 16, 6) << 12;
2631   brtarget |= fieldFromInstruction32(Insn, 26, 1) << 20;
2632 
2633   if (!Check(S, DecodeT2BROperand(Inst, brtarget, Address, Decoder))) return MCDisassembler::Fail;
2634   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder))) return MCDisassembler::Fail;
2635 
2636   return S;
2637 }
2638 
2639 // Decode a shifted immediate operand.  These basically consist
2640 // of an 8-bit value, and a 4-bit directive that specifies either
2641 // a splat operation or a rotation.
2642 static MCDisassembler::DecodeStatus DecodeT2SOImm(llvm::MCInst &Inst, unsigned Val,
2643                           uint64_t Address, const void *Decoder) {
2644   unsigned ctrl = fieldFromInstruction32(Val, 10, 2);
2645   if (ctrl == 0) {
2646     unsigned byte = fieldFromInstruction32(Val, 8, 2);
2647     unsigned imm = fieldFromInstruction32(Val, 0, 8);
2648     switch (byte) {
2649       case 0:
2650         Inst.addOperand(MCOperand::CreateImm(imm));
2651         break;
2652       case 1:
2653         Inst.addOperand(MCOperand::CreateImm((imm << 16) | imm));
2654         break;
2655       case 2:
2656         Inst.addOperand(MCOperand::CreateImm((imm << 24) | (imm << 8)));
2657         break;
2658       case 3:
2659         Inst.addOperand(MCOperand::CreateImm((imm << 24) | (imm << 16) |
2660                                              (imm << 8)  |  imm));
2661         break;
2662     }
2663   } else {
2664     unsigned unrot = fieldFromInstruction32(Val, 0, 7) | 0x80;
2665     unsigned rot = fieldFromInstruction32(Val, 7, 5);
2666     unsigned imm = (unrot >> rot) | (unrot << ((32-rot)&31));
2667     Inst.addOperand(MCOperand::CreateImm(imm));
2668   }
2669 
2670   return MCDisassembler::Success;
2671 }
2672 
2673 static MCDisassembler::DecodeStatus
2674 DecodeThumbBCCTargetOperand(llvm::MCInst &Inst, unsigned Val,
2675                             uint64_t Address, const void *Decoder){
2676   Inst.addOperand(MCOperand::CreateImm(Val << 1));
2677   return MCDisassembler::Success;
2678 }
2679 
2680 static MCDisassembler::DecodeStatus DecodeThumbBLTargetOperand(llvm::MCInst &Inst, unsigned Val,
2681                                        uint64_t Address, const void *Decoder){
2682   Inst.addOperand(MCOperand::CreateImm(SignExtend32<22>(Val << 1)));
2683   return MCDisassembler::Success;
2684 }
2685 
2686 static MCDisassembler::DecodeStatus DecodeMemBarrierOption(llvm::MCInst &Inst, unsigned Val,
2687                                    uint64_t Address, const void *Decoder) {
2688   switch (Val) {
2689   default:
2690     return MCDisassembler::Fail;
2691   case 0xF: // SY
2692   case 0xE: // ST
2693   case 0xB: // ISH
2694   case 0xA: // ISHST
2695   case 0x7: // NSH
2696   case 0x6: // NSHST
2697   case 0x3: // OSH
2698   case 0x2: // OSHST
2699     break;
2700   }
2701 
2702   Inst.addOperand(MCOperand::CreateImm(Val));
2703   return MCDisassembler::Success;
2704 }
2705 
2706 static MCDisassembler::DecodeStatus DecodeMSRMask(llvm::MCInst &Inst, unsigned Val,
2707                           uint64_t Address, const void *Decoder) {
2708   if (!Val) return MCDisassembler::Fail;
2709   Inst.addOperand(MCOperand::CreateImm(Val));
2710   return MCDisassembler::Success;
2711 }
2712 
2713 static MCDisassembler::DecodeStatus DecodeDoubleRegLoad(llvm::MCInst &Inst, unsigned Insn,
2714                                         uint64_t Address, const void *Decoder) {
2715   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
2716 
2717   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2718   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2719   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
2720 
2721   if ((Rt & 1) || Rt == 0xE || Rn == 0xF) return MCDisassembler::Fail;
2722 
2723   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder))) return MCDisassembler::Fail;
2724   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder))) return MCDisassembler::Fail;
2725   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
2726   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder))) return MCDisassembler::Fail;
2727 
2728   return S;
2729 }
2730 
2731 
2732 static MCDisassembler::DecodeStatus DecodeDoubleRegStore(llvm::MCInst &Inst, unsigned Insn,
2733                                          uint64_t Address, const void *Decoder){
2734   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
2735 
2736   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2737   unsigned Rt = fieldFromInstruction32(Insn, 0, 4);
2738   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2739   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
2740 
2741   if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder))) return MCDisassembler::Fail;
2742 
2743   if ((Rt & 1) || Rt == 0xE || Rn == 0xF) return MCDisassembler::Fail;
2744   if (Rd == Rn || Rd == Rt || Rd == Rt+1) return MCDisassembler::Fail;
2745 
2746   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder))) return MCDisassembler::Fail;
2747   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder))) return MCDisassembler::Fail;
2748   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
2749   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder))) return MCDisassembler::Fail;
2750 
2751   return S;
2752 }
2753 
2754 static MCDisassembler::DecodeStatus DecodeLDRPreImm(llvm::MCInst &Inst, unsigned Insn,
2755                             uint64_t Address, const void *Decoder) {
2756   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
2757 
2758   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2759   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2760   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
2761   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
2762   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
2763   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
2764 
2765   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
2766 
2767   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder))) return MCDisassembler::Fail;
2768   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
2769   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder))) return MCDisassembler::Fail;
2770   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder))) return MCDisassembler::Fail;
2771 
2772   return S;
2773 }
2774 
2775 static MCDisassembler::DecodeStatus DecodeLDRPreReg(llvm::MCInst &Inst, unsigned Insn,
2776                             uint64_t Address, const void *Decoder) {
2777   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
2778 
2779   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2780   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2781   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
2782   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
2783   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
2784   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
2785   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2786 
2787   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
2788   if (Rm == 0xF) S = MCDisassembler::SoftFail;
2789 
2790   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder))) return MCDisassembler::Fail;
2791   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
2792   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder))) return MCDisassembler::Fail;
2793   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder))) return MCDisassembler::Fail;
2794 
2795   return S;
2796 }
2797 
2798 
2799 static MCDisassembler::DecodeStatus DecodeSTRPreImm(llvm::MCInst &Inst, unsigned Insn,
2800                             uint64_t Address, const void *Decoder) {
2801   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
2802 
2803   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2804   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2805   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
2806   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
2807   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
2808   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
2809 
2810   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
2811 
2812   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
2813   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder))) return MCDisassembler::Fail;
2814   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder))) return MCDisassembler::Fail;
2815   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder))) return MCDisassembler::Fail;
2816 
2817   return S;
2818 }
2819 
2820 static MCDisassembler::DecodeStatus DecodeSTRPreReg(llvm::MCInst &Inst, unsigned Insn,
2821                             uint64_t Address, const void *Decoder) {
2822   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
2823 
2824   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2825   unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
2826   unsigned imm = fieldFromInstruction32(Insn, 0, 12);
2827   imm |= fieldFromInstruction32(Insn, 16, 4) << 13;
2828   imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
2829   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
2830 
2831   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
2832 
2833   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
2834   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder))) return MCDisassembler::Fail;
2835   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder))) return MCDisassembler::Fail;
2836   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder))) return MCDisassembler::Fail;
2837 
2838   return S;
2839 }
2840 
2841 static MCDisassembler::DecodeStatus DecodeVLD1LN(llvm::MCInst &Inst, unsigned Insn,
2842                          uint64_t Address, const void *Decoder) {
2843   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
2844 
2845   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2846   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2847   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2848   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2849   unsigned size = fieldFromInstruction32(Insn, 10, 2);
2850 
2851   unsigned align = 0;
2852   unsigned index = 0;
2853   switch (size) {
2854     default:
2855       return MCDisassembler::Fail;
2856     case 0:
2857       if (fieldFromInstruction32(Insn, 4, 1))
2858         return MCDisassembler::Fail; // UNDEFINED
2859       index = fieldFromInstruction32(Insn, 5, 3);
2860       break;
2861     case 1:
2862       if (fieldFromInstruction32(Insn, 5, 1))
2863         return MCDisassembler::Fail; // UNDEFINED
2864       index = fieldFromInstruction32(Insn, 6, 2);
2865       if (fieldFromInstruction32(Insn, 4, 1))
2866         align = 2;
2867       break;
2868     case 2:
2869       if (fieldFromInstruction32(Insn, 6, 1))
2870         return MCDisassembler::Fail; // UNDEFINED
2871       index = fieldFromInstruction32(Insn, 7, 1);
2872       if (fieldFromInstruction32(Insn, 4, 2) != 0)
2873         align = 4;
2874   }
2875 
2876   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder))) return MCDisassembler::Fail;
2877   if (Rm != 0xF) { // Writeback
2878     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
2879   }
2880   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
2881   Inst.addOperand(MCOperand::CreateImm(align));
2882   if (Rm != 0xF) {
2883     if (Rm != 0xD) {
2884       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))) return MCDisassembler::Fail;
2885     } else
2886       Inst.addOperand(MCOperand::CreateReg(0));
2887   }
2888 
2889   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder))) return MCDisassembler::Fail;
2890   Inst.addOperand(MCOperand::CreateImm(index));
2891 
2892   return S;
2893 }
2894 
2895 static MCDisassembler::DecodeStatus DecodeVST1LN(llvm::MCInst &Inst, unsigned Insn,
2896                          uint64_t Address, const void *Decoder) {
2897   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
2898 
2899   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2900   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2901   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2902   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2903   unsigned size = fieldFromInstruction32(Insn, 10, 2);
2904 
2905   unsigned align = 0;
2906   unsigned index = 0;
2907   switch (size) {
2908     default:
2909       return MCDisassembler::Fail;
2910     case 0:
2911       if (fieldFromInstruction32(Insn, 4, 1))
2912         return MCDisassembler::Fail; // UNDEFINED
2913       index = fieldFromInstruction32(Insn, 5, 3);
2914       break;
2915     case 1:
2916       if (fieldFromInstruction32(Insn, 5, 1))
2917         return MCDisassembler::Fail; // UNDEFINED
2918       index = fieldFromInstruction32(Insn, 6, 2);
2919       if (fieldFromInstruction32(Insn, 4, 1))
2920         align = 2;
2921       break;
2922     case 2:
2923       if (fieldFromInstruction32(Insn, 6, 1))
2924         return MCDisassembler::Fail; // UNDEFINED
2925       index = fieldFromInstruction32(Insn, 7, 1);
2926       if (fieldFromInstruction32(Insn, 4, 2) != 0)
2927         align = 4;
2928   }
2929 
2930   if (Rm != 0xF) { // Writeback
2931     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
2932   }
2933   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
2934   Inst.addOperand(MCOperand::CreateImm(align));
2935   if (Rm != 0xF) {
2936     if (Rm != 0xD) {
2937       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))) return MCDisassembler::Fail;
2938     } else
2939       Inst.addOperand(MCOperand::CreateReg(0));
2940   }
2941 
2942   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder))) return MCDisassembler::Fail;
2943   Inst.addOperand(MCOperand::CreateImm(index));
2944 
2945   return S;
2946 }
2947 
2948 
2949 static MCDisassembler::DecodeStatus DecodeVLD2LN(llvm::MCInst &Inst, unsigned Insn,
2950                          uint64_t Address, const void *Decoder) {
2951   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
2952 
2953   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
2954   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
2955   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
2956   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
2957   unsigned size = fieldFromInstruction32(Insn, 10, 2);
2958 
2959   unsigned align = 0;
2960   unsigned index = 0;
2961   unsigned inc = 1;
2962   switch (size) {
2963     default:
2964       return MCDisassembler::Fail;
2965     case 0:
2966       index = fieldFromInstruction32(Insn, 5, 3);
2967       if (fieldFromInstruction32(Insn, 4, 1))
2968         align = 2;
2969       break;
2970     case 1:
2971       index = fieldFromInstruction32(Insn, 6, 2);
2972       if (fieldFromInstruction32(Insn, 4, 1))
2973         align = 4;
2974       if (fieldFromInstruction32(Insn, 5, 1))
2975         inc = 2;
2976       break;
2977     case 2:
2978       if (fieldFromInstruction32(Insn, 5, 1))
2979         return MCDisassembler::Fail; // UNDEFINED
2980       index = fieldFromInstruction32(Insn, 7, 1);
2981       if (fieldFromInstruction32(Insn, 4, 1) != 0)
2982         align = 8;
2983       if (fieldFromInstruction32(Insn, 6, 1))
2984         inc = 2;
2985       break;
2986   }
2987 
2988   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder))) return MCDisassembler::Fail;
2989   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder))) return MCDisassembler::Fail;
2990   if (Rm != 0xF) { // Writeback
2991     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
2992   }
2993   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
2994   Inst.addOperand(MCOperand::CreateImm(align));
2995   if (Rm != 0xF) {
2996     if (Rm != 0xD) {
2997       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))) return MCDisassembler::Fail;
2998     } else
2999       Inst.addOperand(MCOperand::CreateReg(0));
3000   }
3001 
3002   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder))) return MCDisassembler::Fail;
3003   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder))) return MCDisassembler::Fail;
3004   Inst.addOperand(MCOperand::CreateImm(index));
3005 
3006   return S;
3007 }
3008 
3009 static MCDisassembler::DecodeStatus DecodeVST2LN(llvm::MCInst &Inst, unsigned Insn,
3010                          uint64_t Address, const void *Decoder) {
3011   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
3012 
3013   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3014   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3015   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3016   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3017   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3018 
3019   unsigned align = 0;
3020   unsigned index = 0;
3021   unsigned inc = 1;
3022   switch (size) {
3023     default:
3024       return MCDisassembler::Fail;
3025     case 0:
3026       index = fieldFromInstruction32(Insn, 5, 3);
3027       if (fieldFromInstruction32(Insn, 4, 1))
3028         align = 2;
3029       break;
3030     case 1:
3031       index = fieldFromInstruction32(Insn, 6, 2);
3032       if (fieldFromInstruction32(Insn, 4, 1))
3033         align = 4;
3034       if (fieldFromInstruction32(Insn, 5, 1))
3035         inc = 2;
3036       break;
3037     case 2:
3038       if (fieldFromInstruction32(Insn, 5, 1))
3039         return MCDisassembler::Fail; // UNDEFINED
3040       index = fieldFromInstruction32(Insn, 7, 1);
3041       if (fieldFromInstruction32(Insn, 4, 1) != 0)
3042         align = 8;
3043       if (fieldFromInstruction32(Insn, 6, 1))
3044         inc = 2;
3045       break;
3046   }
3047 
3048   if (Rm != 0xF) { // Writeback
3049     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
3050   }
3051   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
3052   Inst.addOperand(MCOperand::CreateImm(align));
3053   if (Rm != 0xF) {
3054     if (Rm != 0xD) {
3055       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))) return MCDisassembler::Fail;
3056     } else
3057       Inst.addOperand(MCOperand::CreateReg(0));
3058   }
3059 
3060   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder))) return MCDisassembler::Fail;
3061   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder))) return MCDisassembler::Fail;
3062   Inst.addOperand(MCOperand::CreateImm(index));
3063 
3064   return S;
3065 }
3066 
3067 
3068 static MCDisassembler::DecodeStatus DecodeVLD3LN(llvm::MCInst &Inst, unsigned Insn,
3069                          uint64_t Address, const void *Decoder) {
3070   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
3071 
3072   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3073   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3074   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3075   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3076   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3077 
3078   unsigned align = 0;
3079   unsigned index = 0;
3080   unsigned inc = 1;
3081   switch (size) {
3082     default:
3083       return MCDisassembler::Fail;
3084     case 0:
3085       if (fieldFromInstruction32(Insn, 4, 1))
3086         return MCDisassembler::Fail; // UNDEFINED
3087       index = fieldFromInstruction32(Insn, 5, 3);
3088       break;
3089     case 1:
3090       if (fieldFromInstruction32(Insn, 4, 1))
3091         return MCDisassembler::Fail; // UNDEFINED
3092       index = fieldFromInstruction32(Insn, 6, 2);
3093       if (fieldFromInstruction32(Insn, 5, 1))
3094         inc = 2;
3095       break;
3096     case 2:
3097       if (fieldFromInstruction32(Insn, 4, 2))
3098         return MCDisassembler::Fail; // UNDEFINED
3099       index = fieldFromInstruction32(Insn, 7, 1);
3100       if (fieldFromInstruction32(Insn, 6, 1))
3101         inc = 2;
3102       break;
3103   }
3104 
3105   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder))) return MCDisassembler::Fail;
3106   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder))) return MCDisassembler::Fail;
3107   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder))) return MCDisassembler::Fail;
3108 
3109   if (Rm != 0xF) { // Writeback
3110     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
3111   }
3112   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
3113   Inst.addOperand(MCOperand::CreateImm(align));
3114   if (Rm != 0xF) {
3115     if (Rm != 0xD) {
3116       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))) return MCDisassembler::Fail;
3117     } else
3118       Inst.addOperand(MCOperand::CreateReg(0));
3119   }
3120 
3121   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder))) return MCDisassembler::Fail;
3122   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder))) return MCDisassembler::Fail;
3123   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder))) return MCDisassembler::Fail;
3124   Inst.addOperand(MCOperand::CreateImm(index));
3125 
3126   return S;
3127 }
3128 
3129 static MCDisassembler::DecodeStatus DecodeVST3LN(llvm::MCInst &Inst, unsigned Insn,
3130                          uint64_t Address, const void *Decoder) {
3131   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
3132 
3133   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3134   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3135   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3136   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3137   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3138 
3139   unsigned align = 0;
3140   unsigned index = 0;
3141   unsigned inc = 1;
3142   switch (size) {
3143     default:
3144       return MCDisassembler::Fail;
3145     case 0:
3146       if (fieldFromInstruction32(Insn, 4, 1))
3147         return MCDisassembler::Fail; // UNDEFINED
3148       index = fieldFromInstruction32(Insn, 5, 3);
3149       break;
3150     case 1:
3151       if (fieldFromInstruction32(Insn, 4, 1))
3152         return MCDisassembler::Fail; // UNDEFINED
3153       index = fieldFromInstruction32(Insn, 6, 2);
3154       if (fieldFromInstruction32(Insn, 5, 1))
3155         inc = 2;
3156       break;
3157     case 2:
3158       if (fieldFromInstruction32(Insn, 4, 2))
3159         return MCDisassembler::Fail; // UNDEFINED
3160       index = fieldFromInstruction32(Insn, 7, 1);
3161       if (fieldFromInstruction32(Insn, 6, 1))
3162         inc = 2;
3163       break;
3164   }
3165 
3166   if (Rm != 0xF) { // Writeback
3167     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
3168   }
3169   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
3170   Inst.addOperand(MCOperand::CreateImm(align));
3171   if (Rm != 0xF) {
3172     if (Rm != 0xD) {
3173       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))) return MCDisassembler::Fail;
3174     } else
3175       Inst.addOperand(MCOperand::CreateReg(0));
3176   }
3177 
3178   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder))) return MCDisassembler::Fail;
3179   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder))) return MCDisassembler::Fail;
3180   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder))) return MCDisassembler::Fail;
3181   Inst.addOperand(MCOperand::CreateImm(index));
3182 
3183   return S;
3184 }
3185 
3186 
3187 static MCDisassembler::DecodeStatus DecodeVLD4LN(llvm::MCInst &Inst, unsigned Insn,
3188                          uint64_t Address, const void *Decoder) {
3189   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
3190 
3191   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3192   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3193   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3194   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3195   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3196 
3197   unsigned align = 0;
3198   unsigned index = 0;
3199   unsigned inc = 1;
3200   switch (size) {
3201     default:
3202       return MCDisassembler::Fail;
3203     case 0:
3204       if (fieldFromInstruction32(Insn, 4, 1))
3205         align = 4;
3206       index = fieldFromInstruction32(Insn, 5, 3);
3207       break;
3208     case 1:
3209       if (fieldFromInstruction32(Insn, 4, 1))
3210         align = 8;
3211       index = fieldFromInstruction32(Insn, 6, 2);
3212       if (fieldFromInstruction32(Insn, 5, 1))
3213         inc = 2;
3214       break;
3215     case 2:
3216       if (fieldFromInstruction32(Insn, 4, 2))
3217         align = 4 << fieldFromInstruction32(Insn, 4, 2);
3218       index = fieldFromInstruction32(Insn, 7, 1);
3219       if (fieldFromInstruction32(Insn, 6, 1))
3220         inc = 2;
3221       break;
3222   }
3223 
3224   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder))) return MCDisassembler::Fail;
3225   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder))) return MCDisassembler::Fail;
3226   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder))) return MCDisassembler::Fail;
3227   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder))) return MCDisassembler::Fail;
3228 
3229   if (Rm != 0xF) { // Writeback
3230     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
3231   }
3232   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
3233   Inst.addOperand(MCOperand::CreateImm(align));
3234   if (Rm != 0xF) {
3235     if (Rm != 0xD) {
3236       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))) return MCDisassembler::Fail;
3237     } else
3238       Inst.addOperand(MCOperand::CreateReg(0));
3239   }
3240 
3241   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder))) return MCDisassembler::Fail;
3242   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder))) return MCDisassembler::Fail;
3243   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder))) return MCDisassembler::Fail;
3244   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder))) return MCDisassembler::Fail;
3245   Inst.addOperand(MCOperand::CreateImm(index));
3246 
3247   return S;
3248 }
3249 
3250 static MCDisassembler::DecodeStatus DecodeVST4LN(llvm::MCInst &Inst, unsigned Insn,
3251                          uint64_t Address, const void *Decoder) {
3252   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
3253 
3254   unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
3255   unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
3256   unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
3257   Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
3258   unsigned size = fieldFromInstruction32(Insn, 10, 2);
3259 
3260   unsigned align = 0;
3261   unsigned index = 0;
3262   unsigned inc = 1;
3263   switch (size) {
3264     default:
3265       return MCDisassembler::Fail;
3266     case 0:
3267       if (fieldFromInstruction32(Insn, 4, 1))
3268         align = 4;
3269       index = fieldFromInstruction32(Insn, 5, 3);
3270       break;
3271     case 1:
3272       if (fieldFromInstruction32(Insn, 4, 1))
3273         align = 8;
3274       index = fieldFromInstruction32(Insn, 6, 2);
3275       if (fieldFromInstruction32(Insn, 5, 1))
3276         inc = 2;
3277       break;
3278     case 2:
3279       if (fieldFromInstruction32(Insn, 4, 2))
3280         align = 4 << fieldFromInstruction32(Insn, 4, 2);
3281       index = fieldFromInstruction32(Insn, 7, 1);
3282       if (fieldFromInstruction32(Insn, 6, 1))
3283         inc = 2;
3284       break;
3285   }
3286 
3287   if (Rm != 0xF) { // Writeback
3288     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
3289   }
3290   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))) return MCDisassembler::Fail;
3291   Inst.addOperand(MCOperand::CreateImm(align));
3292   if (Rm != 0xF) {
3293     if (Rm != 0xD) {
3294       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))) return MCDisassembler::Fail;
3295     } else
3296       Inst.addOperand(MCOperand::CreateReg(0));
3297   }
3298 
3299   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder))) return MCDisassembler::Fail;
3300   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder))) return MCDisassembler::Fail;
3301   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder))) return MCDisassembler::Fail;
3302   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder))) return MCDisassembler::Fail;
3303   Inst.addOperand(MCOperand::CreateImm(index));
3304 
3305   return S;
3306 }
3307 
3308 static MCDisassembler::DecodeStatus DecodeVMOVSRR(llvm::MCInst &Inst, unsigned Insn,
3309                                   uint64_t Address, const void *Decoder) {
3310   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
3311   unsigned Rt  = fieldFromInstruction32(Insn, 12, 4);
3312   unsigned Rt2 = fieldFromInstruction32(Insn, 16, 4);
3313   unsigned Rm  = fieldFromInstruction32(Insn,  0, 4);
3314   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3315   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
3316 
3317   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
3318     S = MCDisassembler::SoftFail;
3319 
3320   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder))) return MCDisassembler::Fail;
3321   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder))) return MCDisassembler::Fail;
3322   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder))) return MCDisassembler::Fail;
3323   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder))) return MCDisassembler::Fail;
3324   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder))) return MCDisassembler::Fail;
3325 
3326   return S;
3327 }
3328 
3329 static MCDisassembler::DecodeStatus DecodeVMOVRRS(llvm::MCInst &Inst, unsigned Insn,
3330                                   uint64_t Address, const void *Decoder) {
3331   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
3332   unsigned Rt  = fieldFromInstruction32(Insn, 12, 4);
3333   unsigned Rt2 = fieldFromInstruction32(Insn, 16, 4);
3334   unsigned Rm  = fieldFromInstruction32(Insn,  0, 4);
3335   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
3336   Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
3337 
3338   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
3339     S = MCDisassembler::SoftFail;
3340 
3341   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder))) return MCDisassembler::Fail;
3342   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder))) return MCDisassembler::Fail;
3343   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder))) return MCDisassembler::Fail;
3344   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder))) return MCDisassembler::Fail;
3345   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder))) return MCDisassembler::Fail;
3346 
3347   return S;
3348 }
3349 
3350 static MCDisassembler::DecodeStatus DecodeIT(llvm::MCInst &Inst, unsigned Insn,
3351                              uint64_t Address, const void *Decoder) {
3352   MCDisassembler::DecodeStatus S = MCDisassembler::Success;
3353   unsigned pred = fieldFromInstruction16(Insn, 4, 4);
3354   // The InstPrinter needs to have the low bit of the predicate in
3355   // the mask operand to be able to print it properly.
3356   unsigned mask = fieldFromInstruction16(Insn, 0, 5);
3357 
3358   if (pred == 0xF) {
3359     pred = 0xE;
3360     S = MCDisassembler::SoftFail;
3361   }
3362 
3363   if ((mask & 0xF) == 0) {
3364     // Preserve the high bit of the mask, which is the low bit of
3365     // the predicate.
3366     mask &= 0x10;
3367     mask |= 0x8;
3368     S = MCDisassembler::SoftFail;
3369   }
3370 
3371   Inst.addOperand(MCOperand::CreateImm(pred));
3372   Inst.addOperand(MCOperand::CreateImm(mask));
3373   return S;
3374 }
3375