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      1 // Copyright 2012 the V8 project authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 // A Disassembler object is used to disassemble a block of code instruction by
      6 // instruction. The default implementation of the NameConverter object can be
      7 // overriden to modify register names or to do symbol lookup on addresses.
      8 //
      9 // The example below will disassemble a block of code and print it to stdout.
     10 //
     11 //   NameConverter converter;
     12 //   Disassembler d(converter);
     13 //   for (byte* pc = begin; pc < end;) {
     14 //     v8::internal::EmbeddedVector<char, 256> buffer;
     15 //     byte* prev_pc = pc;
     16 //     pc += d.InstructionDecode(buffer, pc);
     17 //     printf("%p    %08x      %s\n",
     18 //            prev_pc, *reinterpret_cast<int32_t*>(prev_pc), buffer);
     19 //   }
     20 //
     21 // The Disassembler class also has a convenience method to disassemble a block
     22 // of code into a FILE*, meaning that the above functionality could also be
     23 // achieved by just calling Disassembler::Disassemble(stdout, begin, end);
     24 
     25 #include <assert.h>
     26 #include <stdarg.h>
     27 #include <stdio.h>
     28 #include <string.h>
     29 
     30 #if V8_TARGET_ARCH_MIPS
     31 
     32 #include "src/base/platform/platform.h"
     33 #include "src/disasm.h"
     34 #include "src/macro-assembler.h"
     35 #include "src/mips/constants-mips.h"
     36 
     37 namespace v8 {
     38 namespace internal {
     39 
     40 //------------------------------------------------------------------------------
     41 
     42 // Decoder decodes and disassembles instructions into an output buffer.
     43 // It uses the converter to convert register names and call destinations into
     44 // more informative description.
     45 class Decoder {
     46  public:
     47   Decoder(const disasm::NameConverter& converter,
     48           v8::internal::Vector<char> out_buffer)
     49     : converter_(converter),
     50       out_buffer_(out_buffer),
     51       out_buffer_pos_(0) {
     52     out_buffer_[out_buffer_pos_] = '\0';
     53   }
     54 
     55   ~Decoder() {}
     56 
     57   // Writes one disassembled instruction into 'buffer' (0-terminated).
     58   // Returns the length of the disassembled machine instruction in bytes.
     59   int InstructionDecode(byte* instruction);
     60 
     61  private:
     62   // Bottleneck functions to print into the out_buffer.
     63   void PrintChar(const char ch);
     64   void Print(const char* str);
     65 
     66   // Printing of common values.
     67   void PrintRegister(int reg);
     68   void PrintFPURegister(int freg);
     69   void PrintFPUStatusRegister(int freg);
     70   void PrintRs(Instruction* instr);
     71   void PrintRt(Instruction* instr);
     72   void PrintRd(Instruction* instr);
     73   void PrintFs(Instruction* instr);
     74   void PrintFt(Instruction* instr);
     75   void PrintFd(Instruction* instr);
     76   void PrintSa(Instruction* instr);
     77   void PrintLsaSa(Instruction* instr);
     78   void PrintSd(Instruction* instr);
     79   void PrintSs1(Instruction* instr);
     80   void PrintSs2(Instruction* instr);
     81   void PrintBc(Instruction* instr);
     82   void PrintCc(Instruction* instr);
     83   void PrintBp2(Instruction* instr);
     84   void PrintFunction(Instruction* instr);
     85   void PrintSecondaryField(Instruction* instr);
     86   void PrintUImm16(Instruction* instr);
     87   void PrintSImm16(Instruction* instr);
     88   void PrintXImm16(Instruction* instr);
     89   void PrintPCImm16(Instruction* instr, int delta_pc, int n_bits);
     90   void PrintXImm18(Instruction* instr);
     91   void PrintSImm18(Instruction* instr);
     92   void PrintXImm19(Instruction* instr);
     93   void PrintSImm19(Instruction* instr);
     94   void PrintXImm21(Instruction* instr);
     95   void PrintSImm21(Instruction* instr);
     96   void PrintPCImm21(Instruction* instr, int delta_pc, int n_bits);
     97   void PrintXImm26(Instruction* instr);
     98   void PrintSImm26(Instruction* instr);
     99   void PrintPCImm26(Instruction* instr, int delta_pc, int n_bits);
    100   void PrintPCImm26(Instruction* instr);
    101   void PrintCode(Instruction* instr);   // For break and trap instructions.
    102   void PrintFormat(Instruction* instr);  // For floating format postfix.
    103   // Printing of instruction name.
    104   void PrintInstructionName(Instruction* instr);
    105 
    106   // Handle formatting of instructions and their options.
    107   int FormatRegister(Instruction* instr, const char* option);
    108   int FormatFPURegister(Instruction* instr, const char* option);
    109   int FormatOption(Instruction* instr, const char* option);
    110   void Format(Instruction* instr, const char* format);
    111   void Unknown(Instruction* instr);
    112 
    113 
    114   // Each of these functions decodes one particular instruction type.
    115   bool DecodeTypeRegisterRsType(Instruction* instr);
    116   void DecodeTypeRegisterSRsType(Instruction* instr);
    117   void DecodeTypeRegisterDRsType(Instruction* instr);
    118   void DecodeTypeRegisterLRsType(Instruction* instr);
    119   void DecodeTypeRegisterWRsType(Instruction* instr);
    120   void DecodeTypeRegisterSPECIAL(Instruction* instr);
    121   void DecodeTypeRegisterSPECIAL2(Instruction* instr);
    122   void DecodeTypeRegisterSPECIAL3(Instruction* instr);
    123   void DecodeTypeRegister(Instruction* instr);
    124   void DecodeTypeImmediate(Instruction* instr);
    125   void DecodeTypeJump(Instruction* instr);
    126 
    127   const disasm::NameConverter& converter_;
    128   v8::internal::Vector<char> out_buffer_;
    129   int out_buffer_pos_;
    130 
    131   DISALLOW_COPY_AND_ASSIGN(Decoder);
    132 };
    133 
    134 
    135 // Support for assertions in the Decoder formatting functions.
    136 #define STRING_STARTS_WITH(string, compare_string) \
    137   (strncmp(string, compare_string, strlen(compare_string)) == 0)
    138 
    139 
    140 // Append the ch to the output buffer.
    141 void Decoder::PrintChar(const char ch) {
    142   out_buffer_[out_buffer_pos_++] = ch;
    143 }
    144 
    145 
    146 // Append the str to the output buffer.
    147 void Decoder::Print(const char* str) {
    148   char cur = *str++;
    149   while (cur != '\0' && (out_buffer_pos_ < (out_buffer_.length() - 1))) {
    150     PrintChar(cur);
    151     cur = *str++;
    152   }
    153   out_buffer_[out_buffer_pos_] = 0;
    154 }
    155 
    156 
    157 // Print the register name according to the active name converter.
    158 void Decoder::PrintRegister(int reg) {
    159   Print(converter_.NameOfCPURegister(reg));
    160 }
    161 
    162 
    163 void Decoder::PrintRs(Instruction* instr) {
    164   int reg = instr->RsValue();
    165   PrintRegister(reg);
    166 }
    167 
    168 
    169 void Decoder::PrintRt(Instruction* instr) {
    170   int reg = instr->RtValue();
    171   PrintRegister(reg);
    172 }
    173 
    174 
    175 void Decoder::PrintRd(Instruction* instr) {
    176   int reg = instr->RdValue();
    177   PrintRegister(reg);
    178 }
    179 
    180 
    181 // Print the FPUregister name according to the active name converter.
    182 void Decoder::PrintFPURegister(int freg) {
    183   Print(converter_.NameOfXMMRegister(freg));
    184 }
    185 
    186 
    187 void Decoder::PrintFPUStatusRegister(int freg) {
    188   switch (freg) {
    189     case kFCSRRegister:
    190       Print("FCSR");
    191       break;
    192     default:
    193       Print(converter_.NameOfXMMRegister(freg));
    194   }
    195 }
    196 
    197 
    198 void Decoder::PrintFs(Instruction* instr) {
    199   int freg = instr->RsValue();
    200   PrintFPURegister(freg);
    201 }
    202 
    203 
    204 void Decoder::PrintFt(Instruction* instr) {
    205   int freg = instr->RtValue();
    206   PrintFPURegister(freg);
    207 }
    208 
    209 
    210 void Decoder::PrintFd(Instruction* instr) {
    211   int freg = instr->RdValue();
    212   PrintFPURegister(freg);
    213 }
    214 
    215 
    216 // Print the integer value of the sa field.
    217 void Decoder::PrintSa(Instruction* instr) {
    218   int sa = instr->SaValue();
    219   out_buffer_pos_ += SNPrintF(out_buffer_ + out_buffer_pos_, "%d", sa);
    220 }
    221 
    222 
    223 // Print the integer value of the sa field of a lsa instruction.
    224 void Decoder::PrintLsaSa(Instruction* instr) {
    225   int sa = instr->LsaSaValue() + 1;
    226   out_buffer_pos_ += SNPrintF(out_buffer_ + out_buffer_pos_, "%d", sa);
    227 }
    228 
    229 
    230 // Print the integer value of the rd field, when it is not used as reg.
    231 void Decoder::PrintSd(Instruction* instr) {
    232   int sd = instr->RdValue();
    233   out_buffer_pos_ += SNPrintF(out_buffer_ + out_buffer_pos_, "%d", sd);
    234 }
    235 
    236 
    237 // Print the integer value of the rd field, when used as 'ext' size.
    238 void Decoder::PrintSs1(Instruction* instr) {
    239   int ss = instr->RdValue();
    240   out_buffer_pos_ += SNPrintF(out_buffer_ + out_buffer_pos_, "%d", ss + 1);
    241 }
    242 
    243 
    244 // Print the integer value of the rd field, when used as 'ins' size.
    245 void Decoder::PrintSs2(Instruction* instr) {
    246   int ss = instr->RdValue();
    247   int pos = instr->SaValue();
    248   out_buffer_pos_ +=
    249       SNPrintF(out_buffer_ + out_buffer_pos_, "%d", ss - pos + 1);
    250 }
    251 
    252 
    253 // Print the integer value of the cc field for the bc1t/f instructions.
    254 void Decoder::PrintBc(Instruction* instr) {
    255   int cc = instr->FBccValue();
    256   out_buffer_pos_ += SNPrintF(out_buffer_ + out_buffer_pos_, "%d", cc);
    257 }
    258 
    259 
    260 // Print the integer value of the cc field for the FP compare instructions.
    261 void Decoder::PrintCc(Instruction* instr) {
    262   int cc = instr->FCccValue();
    263   out_buffer_pos_ += SNPrintF(out_buffer_ + out_buffer_pos_, "cc(%d)", cc);
    264 }
    265 
    266 
    267 void Decoder::PrintBp2(Instruction* instr) {
    268   int bp2 = instr->Bp2Value();
    269   out_buffer_pos_ += SNPrintF(out_buffer_ + out_buffer_pos_, "%d", bp2);
    270 }
    271 
    272 
    273 // Print 16-bit unsigned immediate value.
    274 void Decoder::PrintUImm16(Instruction* instr) {
    275   int32_t imm = instr->Imm16Value();
    276   out_buffer_pos_ += SNPrintF(out_buffer_ + out_buffer_pos_, "%u", imm);
    277 }
    278 
    279 
    280 // Print 16-bit signed immediate value.
    281 void Decoder::PrintSImm16(Instruction* instr) {
    282   int32_t imm = ((instr->Imm16Value()) << 16) >> 16;
    283   out_buffer_pos_ += SNPrintF(out_buffer_ + out_buffer_pos_, "%d", imm);
    284 }
    285 
    286 
    287 // Print 16-bit hexa immediate value.
    288 void Decoder::PrintXImm16(Instruction* instr) {
    289   int32_t imm = instr->Imm16Value();
    290   out_buffer_pos_ += SNPrintF(out_buffer_ + out_buffer_pos_, "0x%x", imm);
    291 }
    292 
    293 
    294 // Print absoulte address for 16-bit offset or immediate value.
    295 // The absolute address is calculated according following expression:
    296 //      PC + delta_pc + (offset << n_bits)
    297 void Decoder::PrintPCImm16(Instruction* instr, int delta_pc, int n_bits) {
    298   int16_t offset = instr->Imm16Value();
    299   out_buffer_pos_ +=
    300       SNPrintF(out_buffer_ + out_buffer_pos_, "%s",
    301                converter_.NameOfAddress(reinterpret_cast<byte*>(instr) +
    302                                         delta_pc + (offset << n_bits)));
    303 }
    304 
    305 
    306 // Print 18-bit signed immediate value.
    307 void Decoder::PrintSImm18(Instruction* instr) {
    308   int32_t imm =
    309       ((instr->Imm18Value()) << (32 - kImm18Bits)) >> (32 - kImm18Bits);
    310   out_buffer_pos_ += SNPrintF(out_buffer_ + out_buffer_pos_, "%d", imm);
    311 }
    312 
    313 
    314 // Print 18-bit hexa immediate value.
    315 void Decoder::PrintXImm18(Instruction* instr) {
    316   int32_t imm = instr->Imm18Value();
    317   out_buffer_pos_ += SNPrintF(out_buffer_ + out_buffer_pos_, "0x%x", imm);
    318 }
    319 
    320 
    321 // Print 19-bit hexa immediate value.
    322 void Decoder::PrintXImm19(Instruction* instr) {
    323   int32_t imm = instr->Imm19Value();
    324   out_buffer_pos_ += SNPrintF(out_buffer_ + out_buffer_pos_, "0x%x", imm);
    325 }
    326 
    327 
    328 // Print 19-bit signed immediate value.
    329 void Decoder::PrintSImm19(Instruction* instr) {
    330   int32_t imm19 = instr->Imm19Value();
    331   // set sign
    332   imm19 <<= (32 - kImm19Bits);
    333   imm19 >>= (32 - kImm19Bits);
    334   out_buffer_pos_ += SNPrintF(out_buffer_ + out_buffer_pos_, "%d", imm19);
    335 }
    336 
    337 
    338 // Print 21-bit immediate value.
    339 void Decoder::PrintXImm21(Instruction* instr) {
    340   uint32_t imm = instr->Imm21Value();
    341   out_buffer_pos_ += SNPrintF(out_buffer_ + out_buffer_pos_, "0x%x", imm);
    342 }
    343 
    344 
    345 // Print 21-bit signed immediate value.
    346 void Decoder::PrintSImm21(Instruction* instr) {
    347   int32_t imm21 = instr->Imm21Value();
    348   // set sign
    349   imm21 <<= (32 - kImm21Bits);
    350   imm21 >>= (32 - kImm21Bits);
    351   out_buffer_pos_ += SNPrintF(out_buffer_ + out_buffer_pos_, "%d", imm21);
    352 }
    353 
    354 
    355 // Print absoulte address for 21-bit offset or immediate value.
    356 // The absolute address is calculated according following expression:
    357 //      PC + delta_pc + (offset << n_bits)
    358 void Decoder::PrintPCImm21(Instruction* instr, int delta_pc, int n_bits) {
    359   int32_t imm21 = instr->Imm21Value();
    360   // set sign
    361   imm21 <<= (32 - kImm21Bits);
    362   imm21 >>= (32 - kImm21Bits);
    363   out_buffer_pos_ +=
    364       SNPrintF(out_buffer_ + out_buffer_pos_, "%s",
    365                converter_.NameOfAddress(reinterpret_cast<byte*>(instr) +
    366                                         delta_pc + (imm21 << n_bits)));
    367 }
    368 
    369 
    370 // Print 26-bit hex immediate value.
    371 void Decoder::PrintXImm26(Instruction* instr) {
    372   uint32_t target = static_cast<uint32_t>(instr->Imm26Value())
    373                     << kImmFieldShift;
    374   target = (reinterpret_cast<uint32_t>(instr) & ~0xfffffff) | target;
    375   out_buffer_pos_ += SNPrintF(out_buffer_ + out_buffer_pos_, "0x%x", target);
    376 }
    377 
    378 
    379 // Print 26-bit signed immediate value.
    380 void Decoder::PrintSImm26(Instruction* instr) {
    381   int32_t imm26 = instr->Imm26Value();
    382   // set sign
    383   imm26 <<= (32 - kImm26Bits);
    384   imm26 >>= (32 - kImm26Bits);
    385   out_buffer_pos_ += SNPrintF(out_buffer_ + out_buffer_pos_, "%d", imm26);
    386 }
    387 
    388 
    389 // Print absoulte address for 26-bit offset or immediate value.
    390 // The absolute address is calculated according following expression:
    391 //      PC + delta_pc + (offset << n_bits)
    392 void Decoder::PrintPCImm26(Instruction* instr, int delta_pc, int n_bits) {
    393   int32_t imm26 = instr->Imm26Value();
    394   // set sign
    395   imm26 <<= (32 - kImm26Bits);
    396   imm26 >>= (32 - kImm26Bits);
    397   out_buffer_pos_ +=
    398       SNPrintF(out_buffer_ + out_buffer_pos_, "%s",
    399                converter_.NameOfAddress(reinterpret_cast<byte*>(instr) +
    400                                         delta_pc + (imm26 << n_bits)));
    401 }
    402 
    403 
    404 // Print absoulte address for 26-bit offset or immediate value.
    405 // The absolute address is calculated according following expression:
    406 //      PC[GPRLEN-1 .. 28] || instr_index26 || 00
    407 void Decoder::PrintPCImm26(Instruction* instr) {
    408   int32_t imm26 = instr->Imm26Value();
    409   uint32_t pc_mask = ~0xfffffff;
    410   uint32_t pc = ((uint32_t)(instr + 1) & pc_mask) | (imm26 << 2);
    411   out_buffer_pos_ +=
    412       SNPrintF(out_buffer_ + out_buffer_pos_, "%s",
    413                converter_.NameOfAddress((reinterpret_cast<byte*>(pc))));
    414 }
    415 
    416 
    417 // Print 26-bit immediate value.
    418 void Decoder::PrintCode(Instruction* instr) {
    419   if (instr->OpcodeFieldRaw() != SPECIAL)
    420     return;  // Not a break or trap instruction.
    421   switch (instr->FunctionFieldRaw()) {
    422     case BREAK: {
    423       int32_t code = instr->Bits(25, 6);
    424       out_buffer_pos_ += SNPrintF(out_buffer_ + out_buffer_pos_,
    425                                   "0x%05x (%d)", code, code);
    426       break;
    427                 }
    428     case TGE:
    429     case TGEU:
    430     case TLT:
    431     case TLTU:
    432     case TEQ:
    433     case TNE: {
    434       int32_t code = instr->Bits(15, 6);
    435       out_buffer_pos_ +=
    436           SNPrintF(out_buffer_ + out_buffer_pos_, "0x%03x", code);
    437       break;
    438     }
    439     default:  // Not a break or trap instruction.
    440     break;
    441   }
    442 }
    443 
    444 
    445 void Decoder::PrintFormat(Instruction* instr) {
    446   char formatLetter = ' ';
    447   switch (instr->RsFieldRaw()) {
    448     case S:
    449       formatLetter = 's';
    450       break;
    451     case D:
    452       formatLetter = 'd';
    453       break;
    454     case W:
    455       formatLetter = 'w';
    456       break;
    457     case L:
    458       formatLetter = 'l';
    459       break;
    460     default:
    461       UNREACHABLE();
    462       break;
    463   }
    464   PrintChar(formatLetter);
    465 }
    466 
    467 
    468 // Printing of instruction name.
    469 void Decoder::PrintInstructionName(Instruction* instr) {
    470 }
    471 
    472 
    473 // Handle all register based formatting in this function to reduce the
    474 // complexity of FormatOption.
    475 int Decoder::FormatRegister(Instruction* instr, const char* format) {
    476   DCHECK(format[0] == 'r');
    477   if (format[1] == 's') {  // 'rs: Rs register.
    478     int reg = instr->RsValue();
    479     PrintRegister(reg);
    480     return 2;
    481   } else if (format[1] == 't') {  // 'rt: rt register.
    482     int reg = instr->RtValue();
    483     PrintRegister(reg);
    484     return 2;
    485   } else if (format[1] == 'd') {  // 'rd: rd register.
    486     int reg = instr->RdValue();
    487     PrintRegister(reg);
    488     return 2;
    489   }
    490   UNREACHABLE();
    491   return -1;
    492 }
    493 
    494 
    495 // Handle all FPUregister based formatting in this function to reduce the
    496 // complexity of FormatOption.
    497 int Decoder::FormatFPURegister(Instruction* instr, const char* format) {
    498   DCHECK(format[0] == 'f');
    499   if ((CTC1 == instr->RsFieldRaw()) || (CFC1 == instr->RsFieldRaw())) {
    500     if (format[1] == 's') {  // 'fs: fs register.
    501       int reg = instr->FsValue();
    502       PrintFPUStatusRegister(reg);
    503       return 2;
    504     } else if (format[1] == 't') {  // 'ft: ft register.
    505       int reg = instr->FtValue();
    506       PrintFPUStatusRegister(reg);
    507       return 2;
    508     } else if (format[1] == 'd') {  // 'fd: fd register.
    509       int reg = instr->FdValue();
    510       PrintFPUStatusRegister(reg);
    511       return 2;
    512     } else if (format[1] == 'r') {  // 'fr: fr register.
    513       int reg = instr->FrValue();
    514       PrintFPUStatusRegister(reg);
    515       return 2;
    516     }
    517   } else {
    518     if (format[1] == 's') {  // 'fs: fs register.
    519       int reg = instr->FsValue();
    520       PrintFPURegister(reg);
    521       return 2;
    522     } else if (format[1] == 't') {  // 'ft: ft register.
    523       int reg = instr->FtValue();
    524       PrintFPURegister(reg);
    525       return 2;
    526     } else if (format[1] == 'd') {  // 'fd: fd register.
    527       int reg = instr->FdValue();
    528       PrintFPURegister(reg);
    529       return 2;
    530     } else if (format[1] == 'r') {  // 'fr: fr register.
    531       int reg = instr->FrValue();
    532       PrintFPURegister(reg);
    533       return 2;
    534     }
    535   }
    536   UNREACHABLE();
    537   return -1;
    538 }
    539 
    540 
    541 // FormatOption takes a formatting string and interprets it based on
    542 // the current instructions. The format string points to the first
    543 // character of the option string (the option escape has already been
    544 // consumed by the caller.)  FormatOption returns the number of
    545 // characters that were consumed from the formatting string.
    546 int Decoder::FormatOption(Instruction* instr, const char* format) {
    547   switch (format[0]) {
    548     case 'c': {   // 'code for break or trap instructions.
    549       DCHECK(STRING_STARTS_WITH(format, "code"));
    550       PrintCode(instr);
    551       return 4;
    552     }
    553     case 'i': {   // 'imm16u or 'imm26.
    554       if (format[3] == '1') {
    555         if (format[4] == '6') {
    556           DCHECK(STRING_STARTS_WITH(format, "imm16"));
    557           switch (format[5]) {
    558             case 's':
    559               DCHECK(STRING_STARTS_WITH(format, "imm16s"));
    560               PrintSImm16(instr);
    561               break;
    562             case 'u':
    563               DCHECK(STRING_STARTS_WITH(format, "imm16u"));
    564               PrintSImm16(instr);
    565               break;
    566             case 'x':
    567               DCHECK(STRING_STARTS_WITH(format, "imm16x"));
    568               PrintXImm16(instr);
    569               break;
    570             case 'p': {  // The PC relative address.
    571               DCHECK(STRING_STARTS_WITH(format, "imm16p"));
    572               int delta_pc = 0;
    573               int n_bits = 0;
    574               switch (format[6]) {
    575                 case '4': {
    576                   DCHECK(STRING_STARTS_WITH(format, "imm16p4"));
    577                   delta_pc = 4;
    578                   switch (format[8]) {
    579                     case '2':
    580                       DCHECK(STRING_STARTS_WITH(format, "imm16p4s2"));
    581                       n_bits = 2;
    582                       PrintPCImm16(instr, delta_pc, n_bits);
    583                       return 9;
    584                   }
    585                 }
    586               }
    587             }
    588           }
    589           return 6;
    590         } else if (format[4] == '8') {
    591           DCHECK(STRING_STARTS_WITH(format, "imm18"));
    592           switch (format[5]) {
    593             case 's':
    594               DCHECK(STRING_STARTS_WITH(format, "imm18s"));
    595               PrintSImm18(instr);
    596               break;
    597             case 'x':
    598               DCHECK(STRING_STARTS_WITH(format, "imm18x"));
    599               PrintXImm18(instr);
    600               break;
    601           }
    602           return 6;
    603         } else if (format[4] == '9') {
    604           DCHECK(STRING_STARTS_WITH(format, "imm19"));
    605           switch (format[5]) {
    606             case 's':
    607               DCHECK(STRING_STARTS_WITH(format, "imm19s"));
    608               PrintSImm19(instr);
    609               break;
    610             case 'x':
    611               DCHECK(STRING_STARTS_WITH(format, "imm19x"));
    612               PrintXImm19(instr);
    613               break;
    614           }
    615           return 6;
    616         }
    617       } else if (format[3] == '2' && format[4] == '1') {
    618         DCHECK(STRING_STARTS_WITH(format, "imm21"));
    619         switch (format[5]) {
    620           case 's':
    621             DCHECK(STRING_STARTS_WITH(format, "imm21s"));
    622             PrintSImm21(instr);
    623             break;
    624           case 'x':
    625             DCHECK(STRING_STARTS_WITH(format, "imm21x"));
    626             PrintXImm21(instr);
    627             break;
    628           case 'p': {  // The PC relative address.
    629             DCHECK(STRING_STARTS_WITH(format, "imm21p"));
    630             int delta_pc = 0;
    631             int n_bits = 0;
    632             switch (format[6]) {
    633               case '4': {
    634                 DCHECK(STRING_STARTS_WITH(format, "imm21p4"));
    635                 delta_pc = 4;
    636                 switch (format[8]) {
    637                   case '2':
    638                     DCHECK(STRING_STARTS_WITH(format, "imm21p4s2"));
    639                     n_bits = 2;
    640                     PrintPCImm21(instr, delta_pc, n_bits);
    641                     return 9;
    642                 }
    643               }
    644             }
    645           }
    646         }
    647         return 6;
    648       } else if (format[3] == '2' && format[4] == '6') {
    649         DCHECK(STRING_STARTS_WITH(format, "imm26"));
    650         switch (format[5]) {
    651           case 's':
    652             DCHECK(STRING_STARTS_WITH(format, "imm26s"));
    653             PrintSImm26(instr);
    654             break;
    655           case 'x':
    656             DCHECK(STRING_STARTS_WITH(format, "imm26x"));
    657             PrintXImm26(instr);
    658             break;
    659           case 'p': {  // The PC relative address.
    660             DCHECK(STRING_STARTS_WITH(format, "imm26p"));
    661             int delta_pc = 0;
    662             int n_bits = 0;
    663             switch (format[6]) {
    664               case '4': {
    665                 DCHECK(STRING_STARTS_WITH(format, "imm26p4"));
    666                 delta_pc = 4;
    667                 switch (format[8]) {
    668                   case '2':
    669                     DCHECK(STRING_STARTS_WITH(format, "imm26p4s2"));
    670                     n_bits = 2;
    671                     PrintPCImm26(instr, delta_pc, n_bits);
    672                     return 9;
    673                 }
    674               }
    675             }
    676           }
    677           case 'j': {  // Absolute address for jump instructions.
    678             DCHECK(STRING_STARTS_WITH(format, "imm26j"));
    679             PrintPCImm26(instr);
    680             break;
    681           }
    682         }
    683         return 6;
    684       }
    685     }
    686     case 'r': {   // 'r: registers.
    687       return FormatRegister(instr, format);
    688     }
    689     case 'f': {   // 'f: FPUregisters.
    690       return FormatFPURegister(instr, format);
    691     }
    692     case 's': {   // 'sa.
    693       switch (format[1]) {
    694         case 'a':
    695           if (format[2] == '2') {
    696             DCHECK(STRING_STARTS_WITH(format, "sa2"));  // 'sa2
    697             PrintLsaSa(instr);
    698             return 3;
    699           } else {
    700             DCHECK(STRING_STARTS_WITH(format, "sa"));
    701             PrintSa(instr);
    702             return 2;
    703           }
    704           break;
    705         case 'd': {
    706           DCHECK(STRING_STARTS_WITH(format, "sd"));
    707           PrintSd(instr);
    708           return 2;
    709         }
    710         case 's': {
    711           if (format[2] == '1') {
    712               DCHECK(STRING_STARTS_WITH(format, "ss1"));  /* ext size */
    713               PrintSs1(instr);
    714               return 3;
    715           } else {
    716               DCHECK(STRING_STARTS_WITH(format, "ss2"));  /* ins size */
    717               PrintSs2(instr);
    718               return 3;
    719           }
    720         }
    721       }
    722     }
    723     case 'b': {
    724       switch (format[1]) {
    725         case 'c': {  // 'bc - Special for bc1 cc field.
    726           DCHECK(STRING_STARTS_WITH(format, "bc"));
    727           PrintBc(instr);
    728           return 2;
    729         }
    730         case 'p': {
    731           switch (format[2]) {
    732             case '2': {  // 'bp2
    733               DCHECK(STRING_STARTS_WITH(format, "bp2"));
    734               PrintBp2(instr);
    735               return 3;
    736             }
    737           }
    738         }
    739       }
    740     }
    741     case 'C': {   // 'Cc - Special for c.xx.d cc field.
    742       DCHECK(STRING_STARTS_WITH(format, "Cc"));
    743       PrintCc(instr);
    744       return 2;
    745     }
    746     case 't':
    747       PrintFormat(instr);
    748       return 1;
    749   }
    750   UNREACHABLE();
    751   return -1;
    752 }
    753 
    754 
    755 // Format takes a formatting string for a whole instruction and prints it into
    756 // the output buffer. All escaped options are handed to FormatOption to be
    757 // parsed further.
    758 void Decoder::Format(Instruction* instr, const char* format) {
    759   char cur = *format++;
    760   while ((cur != 0) && (out_buffer_pos_ < (out_buffer_.length() - 1))) {
    761     if (cur == '\'') {  // Single quote is used as the formatting escape.
    762       format += FormatOption(instr, format);
    763     } else {
    764       out_buffer_[out_buffer_pos_++] = cur;
    765     }
    766     cur = *format++;
    767   }
    768   out_buffer_[out_buffer_pos_]  = '\0';
    769 }
    770 
    771 
    772 // For currently unimplemented decodings the disassembler calls Unknown(instr)
    773 // which will just print "unknown" of the instruction bits.
    774 void Decoder::Unknown(Instruction* instr) {
    775   Format(instr, "unknown");
    776 }
    777 
    778 
    779 bool Decoder::DecodeTypeRegisterRsType(Instruction* instr) {
    780   switch (instr->FunctionFieldRaw()) {
    781     case RINT:
    782       Format(instr, "rint.'t    'fd, 'fs");
    783       break;
    784     case MIN:
    785       Format(instr, "min.'t    'fd, 'fs, 'ft");
    786       break;
    787     case MAX:
    788       Format(instr, "max.'t    'fd, 'fs, 'ft");
    789       break;
    790     case MINA:
    791       Format(instr, "mina.'t   'fd, 'fs, 'ft");
    792       break;
    793     case MAXA:
    794       Format(instr, "maxa.'t   'fd, 'fs, 'ft");
    795       break;
    796     case SEL:
    797       Format(instr, "sel.'t      'fd, 'fs, 'ft");
    798       break;
    799     case SELEQZ_C:
    800       Format(instr, "seleqz.'t    'fd, 'fs, 'ft");
    801       break;
    802     case SELNEZ_C:
    803       Format(instr, "selnez.'t    'fd, 'fs, 'ft");
    804       break;
    805     case MOVZ_C:
    806       Format(instr, "movz.'t    'fd, 'fs, 'rt");
    807       break;
    808     case MOVN_C:
    809       Format(instr, "movn.'t    'fd, 'fs, 'rt");
    810       break;
    811     case MOVF:
    812       if (instr->Bit(16)) {
    813         Format(instr, "movt.'t    'fd, 'fs, 'Cc");
    814       } else {
    815         Format(instr, "movf.'t    'fd, 'fs, 'Cc");
    816       }
    817       break;
    818     case ADD_D:
    819       Format(instr, "add.'t   'fd, 'fs, 'ft");
    820       break;
    821     case SUB_D:
    822       Format(instr, "sub.'t   'fd, 'fs, 'ft");
    823       break;
    824     case MUL_D:
    825       Format(instr, "mul.'t   'fd, 'fs, 'ft");
    826       break;
    827     case DIV_D:
    828       Format(instr, "div.'t   'fd, 'fs, 'ft");
    829       break;
    830     case ABS_D:
    831       Format(instr, "abs.'t   'fd, 'fs");
    832       break;
    833     case MOV_D:
    834       Format(instr, "mov.'t   'fd, 'fs");
    835       break;
    836     case NEG_D:
    837       Format(instr, "neg.'t   'fd, 'fs");
    838       break;
    839     case SQRT_D:
    840       Format(instr, "sqrt.'t  'fd, 'fs");
    841       break;
    842     case RECIP_D:
    843       Format(instr, "recip.'t  'fd, 'fs");
    844       break;
    845     case RSQRT_D:
    846       Format(instr, "rsqrt.'t  'fd, 'fs");
    847       break;
    848     case CVT_W_D:
    849       Format(instr, "cvt.w.'t 'fd, 'fs");
    850       break;
    851     case CVT_L_D:
    852       Format(instr, "cvt.l.'t 'fd, 'fs");
    853       break;
    854     case TRUNC_W_D:
    855       Format(instr, "trunc.w.'t 'fd, 'fs");
    856       break;
    857     case TRUNC_L_D:
    858       Format(instr, "trunc.l.'t 'fd, 'fs");
    859       break;
    860     case ROUND_W_D:
    861       Format(instr, "round.w.'t 'fd, 'fs");
    862       break;
    863     case ROUND_L_D:
    864       Format(instr, "round.l.'t 'fd, 'fs");
    865       break;
    866     case FLOOR_W_D:
    867       Format(instr, "floor.w.'t 'fd, 'fs");
    868       break;
    869     case FLOOR_L_D:
    870       Format(instr, "floor.l.'t 'fd, 'fs");
    871       break;
    872     case CEIL_W_D:
    873       Format(instr, "ceil.w.'t 'fd, 'fs");
    874       break;
    875     case CLASS_D:
    876       Format(instr, "class.'t 'fd, 'fs");
    877       break;
    878     case CEIL_L_D:
    879       Format(instr, "ceil.l.'t 'fd, 'fs");
    880       break;
    881     case CVT_S_D:
    882       Format(instr, "cvt.s.'t 'fd, 'fs");
    883       break;
    884     case C_F_D:
    885       Format(instr, "c.f.'t   'fs, 'ft, 'Cc");
    886       break;
    887     case C_UN_D:
    888       Format(instr, "c.un.'t  'fs, 'ft, 'Cc");
    889       break;
    890     case C_EQ_D:
    891       Format(instr, "c.eq.'t  'fs, 'ft, 'Cc");
    892       break;
    893     case C_UEQ_D:
    894       Format(instr, "c.ueq.'t 'fs, 'ft, 'Cc");
    895       break;
    896     case C_OLT_D:
    897       Format(instr, "c.olt.'t 'fs, 'ft, 'Cc");
    898       break;
    899     case C_ULT_D:
    900       Format(instr, "c.ult.'t 'fs, 'ft, 'Cc");
    901       break;
    902     case C_OLE_D:
    903       Format(instr, "c.ole.'t 'fs, 'ft, 'Cc");
    904       break;
    905     case C_ULE_D:
    906       Format(instr, "c.ule.'t 'fs, 'ft, 'Cc");
    907       break;
    908     default:
    909       return false;
    910   }
    911   return true;
    912 }
    913 
    914 
    915 void Decoder::DecodeTypeRegisterSRsType(Instruction* instr) {
    916   if (!DecodeTypeRegisterRsType(instr)) {
    917     switch (instr->FunctionFieldRaw()) {
    918       case CVT_D_S:
    919         Format(instr, "cvt.d.'t 'fd, 'fs");
    920         break;
    921       case MADDF_S:
    922         Format(instr, "maddf.s  'fd, 'fs, 'ft");
    923         break;
    924       case MSUBF_S:
    925         Format(instr, "msubf.s  'fd, 'fs, 'ft");
    926         break;
    927       default:
    928         Format(instr, "unknown.cop1.'t");
    929         break;
    930     }
    931   }
    932 }
    933 
    934 
    935 void Decoder::DecodeTypeRegisterDRsType(Instruction* instr) {
    936   if (!DecodeTypeRegisterRsType(instr)) {
    937     switch (instr->FunctionFieldRaw()) {
    938       case MADDF_D:
    939         Format(instr, "maddf.d  'fd, 'fs, 'ft");
    940         break;
    941       case MSUBF_D:
    942         Format(instr, "msubf.d  'fd, 'fs, 'ft");
    943         break;
    944       default:
    945         Format(instr, "unknown.cop1.'t");
    946         break;
    947     }
    948   }
    949 }
    950 
    951 
    952 void Decoder::DecodeTypeRegisterLRsType(Instruction* instr) {
    953   switch (instr->FunctionFieldRaw()) {
    954     case CVT_D_L:
    955       Format(instr, "cvt.d.l 'fd, 'fs");
    956       break;
    957     case CVT_S_L:
    958       Format(instr, "cvt.s.l 'fd, 'fs");
    959       break;
    960     case CMP_AF:
    961       Format(instr, "cmp.af.d  'fd,  'fs, 'ft");
    962       break;
    963     case CMP_UN:
    964       Format(instr, "cmp.un.d  'fd,  'fs, 'ft");
    965       break;
    966     case CMP_EQ:
    967       Format(instr, "cmp.eq.d  'fd,  'fs, 'ft");
    968       break;
    969     case CMP_UEQ:
    970       Format(instr, "cmp.ueq.d  'fd,  'fs, 'ft");
    971       break;
    972     case CMP_LT:
    973       Format(instr, "cmp.lt.d  'fd,  'fs, 'ft");
    974       break;
    975     case CMP_ULT:
    976       Format(instr, "cmp.ult.d  'fd,  'fs, 'ft");
    977       break;
    978     case CMP_LE:
    979       Format(instr, "cmp.le.d  'fd,  'fs, 'ft");
    980       break;
    981     case CMP_ULE:
    982       Format(instr, "cmp.ule.d  'fd,  'fs, 'ft");
    983       break;
    984     case CMP_OR:
    985       Format(instr, "cmp.or.d  'fd,  'fs, 'ft");
    986       break;
    987     case CMP_UNE:
    988       Format(instr, "cmp.une.d  'fd,  'fs, 'ft");
    989       break;
    990     case CMP_NE:
    991       Format(instr, "cmp.ne.d  'fd,  'fs, 'ft");
    992       break;
    993     default:
    994       UNREACHABLE();
    995   }
    996 }
    997 
    998 
    999 void Decoder::DecodeTypeRegisterWRsType(Instruction* instr) {
   1000   switch (instr->FunctionValue()) {
   1001     case CVT_S_W:  // Convert word to float (single).
   1002       Format(instr, "cvt.s.w 'fd, 'fs");
   1003       break;
   1004     case CVT_D_W:  // Convert word to double.
   1005       Format(instr, "cvt.d.w 'fd, 'fs");
   1006       break;
   1007     case CMP_AF:
   1008       Format(instr, "cmp.af.s    'fd, 'fs, 'ft");
   1009       break;
   1010     case CMP_UN:
   1011       Format(instr, "cmp.un.s    'fd, 'fs, 'ft");
   1012       break;
   1013     case CMP_EQ:
   1014       Format(instr, "cmp.eq.s    'fd, 'fs, 'ft");
   1015       break;
   1016     case CMP_UEQ:
   1017       Format(instr, "cmp.ueq.s   'fd, 'fs, 'ft");
   1018       break;
   1019     case CMP_LT:
   1020       Format(instr, "cmp.lt.s    'fd, 'fs, 'ft");
   1021       break;
   1022     case CMP_ULT:
   1023       Format(instr, "cmp.ult.s   'fd, 'fs, 'ft");
   1024       break;
   1025     case CMP_LE:
   1026       Format(instr, "cmp.le.s    'fd, 'fs, 'ft");
   1027       break;
   1028     case CMP_ULE:
   1029       Format(instr, "cmp.ule.s   'fd, 'fs, 'ft");
   1030       break;
   1031     case CMP_OR:
   1032       Format(instr, "cmp.or.s    'fd, 'fs, 'ft");
   1033       break;
   1034     case CMP_UNE:
   1035       Format(instr, "cmp.une.s   'fd, 'fs, 'ft");
   1036       break;
   1037     case CMP_NE:
   1038       Format(instr, "cmp.ne.s    'fd, 'fs, 'ft");
   1039       break;
   1040     default:
   1041       UNREACHABLE();
   1042   }
   1043 }
   1044 
   1045 
   1046 void Decoder::DecodeTypeRegisterSPECIAL(Instruction* instr) {
   1047   switch (instr->FunctionFieldRaw()) {
   1048     case JR:
   1049       Format(instr, "jr      'rs");
   1050       break;
   1051     case JALR:
   1052       Format(instr, "jalr    'rs, 'rd");
   1053       break;
   1054     case SLL:
   1055       if (0x0 == static_cast<int>(instr->InstructionBits()))
   1056         Format(instr, "nop");
   1057       else
   1058         Format(instr, "sll     'rd, 'rt, 'sa");
   1059       break;
   1060     case SRL:
   1061       if (instr->RsValue() == 0) {
   1062         Format(instr, "srl     'rd, 'rt, 'sa");
   1063       } else {
   1064         if (IsMipsArchVariant(kMips32r2)) {
   1065           Format(instr, "rotr    'rd, 'rt, 'sa");
   1066         } else {
   1067           Unknown(instr);
   1068         }
   1069       }
   1070       break;
   1071     case SRA:
   1072       Format(instr, "sra     'rd, 'rt, 'sa");
   1073       break;
   1074     case SLLV:
   1075       Format(instr, "sllv    'rd, 'rt, 'rs");
   1076       break;
   1077     case SRLV:
   1078       if (instr->SaValue() == 0) {
   1079         Format(instr, "srlv    'rd, 'rt, 'rs");
   1080       } else {
   1081         if (IsMipsArchVariant(kMips32r2)) {
   1082           Format(instr, "rotrv   'rd, 'rt, 'rs");
   1083         } else {
   1084           Unknown(instr);
   1085         }
   1086       }
   1087       break;
   1088     case SRAV:
   1089       Format(instr, "srav    'rd, 'rt, 'rs");
   1090       break;
   1091     case LSA:
   1092       Format(instr, "lsa     'rd, 'rt, 'rs, 'sa2");
   1093       break;
   1094     case MFHI:
   1095       if (instr->Bits(25, 16) == 0) {
   1096         Format(instr, "mfhi    'rd");
   1097       } else {
   1098         if ((instr->FunctionFieldRaw() == CLZ_R6) && (instr->FdValue() == 1)) {
   1099           Format(instr, "clz     'rd, 'rs");
   1100         } else if ((instr->FunctionFieldRaw() == CLO_R6) &&
   1101                    (instr->FdValue() == 1)) {
   1102           Format(instr, "clo     'rd, 'rs");
   1103         }
   1104       }
   1105       break;
   1106     case MFLO:
   1107       Format(instr, "mflo    'rd");
   1108       break;
   1109     case MULT:  // @Mips32r6 == MUL_MUH.
   1110       if (!IsMipsArchVariant(kMips32r6)) {
   1111         Format(instr, "mult    'rs, 'rt");
   1112       } else {
   1113         if (instr->SaValue() == MUL_OP) {
   1114           Format(instr, "mul    'rd, 'rs, 'rt");
   1115         } else {
   1116           Format(instr, "muh    'rd, 'rs, 'rt");
   1117         }
   1118       }
   1119       break;
   1120     case MULTU:  // @Mips32r6 == MUL_MUH_U.
   1121       if (!IsMipsArchVariant(kMips32r6)) {
   1122         Format(instr, "multu   'rs, 'rt");
   1123       } else {
   1124         if (instr->SaValue() == MUL_OP) {
   1125           Format(instr, "mulu   'rd, 'rs, 'rt");
   1126         } else {
   1127           Format(instr, "muhu   'rd, 'rs, 'rt");
   1128         }
   1129       }
   1130       break;
   1131     case DIV:  // @Mips32r6 == DIV_MOD.
   1132       if (!IsMipsArchVariant(kMips32r6)) {
   1133         Format(instr, "div     'rs, 'rt");
   1134       } else {
   1135         if (instr->SaValue() == DIV_OP) {
   1136           Format(instr, "div    'rd, 'rs, 'rt");
   1137         } else {
   1138           Format(instr, "mod    'rd, 'rs, 'rt");
   1139         }
   1140       }
   1141       break;
   1142     case DIVU:  // @Mips32r6 == DIV_MOD_U.
   1143       if (!IsMipsArchVariant(kMips32r6)) {
   1144         Format(instr, "divu    'rs, 'rt");
   1145       } else {
   1146         if (instr->SaValue() == DIV_OP) {
   1147           Format(instr, "divu   'rd, 'rs, 'rt");
   1148         } else {
   1149           Format(instr, "modu   'rd, 'rs, 'rt");
   1150         }
   1151       }
   1152       break;
   1153     case ADD:
   1154       Format(instr, "add     'rd, 'rs, 'rt");
   1155       break;
   1156     case ADDU:
   1157       Format(instr, "addu    'rd, 'rs, 'rt");
   1158       break;
   1159     case SUB:
   1160       Format(instr, "sub     'rd, 'rs, 'rt");
   1161       break;
   1162     case SUBU:
   1163       Format(instr, "subu    'rd, 'rs, 'rt");
   1164       break;
   1165     case AND:
   1166       Format(instr, "and     'rd, 'rs, 'rt");
   1167       break;
   1168     case OR:
   1169       if (0 == instr->RsValue()) {
   1170         Format(instr, "mov     'rd, 'rt");
   1171       } else if (0 == instr->RtValue()) {
   1172         Format(instr, "mov     'rd, 'rs");
   1173       } else {
   1174         Format(instr, "or      'rd, 'rs, 'rt");
   1175       }
   1176       break;
   1177     case XOR:
   1178       Format(instr, "xor     'rd, 'rs, 'rt");
   1179       break;
   1180     case NOR:
   1181       Format(instr, "nor     'rd, 'rs, 'rt");
   1182       break;
   1183     case SLT:
   1184       Format(instr, "slt     'rd, 'rs, 'rt");
   1185       break;
   1186     case SLTU:
   1187       Format(instr, "sltu    'rd, 'rs, 'rt");
   1188       break;
   1189     case BREAK:
   1190       Format(instr, "break, code: 'code");
   1191       break;
   1192     case TGE:
   1193       Format(instr, "tge     'rs, 'rt, code: 'code");
   1194       break;
   1195     case TGEU:
   1196       Format(instr, "tgeu    'rs, 'rt, code: 'code");
   1197       break;
   1198     case TLT:
   1199       Format(instr, "tlt     'rs, 'rt, code: 'code");
   1200       break;
   1201     case TLTU:
   1202       Format(instr, "tltu    'rs, 'rt, code: 'code");
   1203       break;
   1204     case TEQ:
   1205       Format(instr, "teq     'rs, 'rt, code: 'code");
   1206       break;
   1207     case TNE:
   1208       Format(instr, "tne     'rs, 'rt, code: 'code");
   1209       break;
   1210     case SYNC:
   1211       Format(instr, "sync");
   1212       break;
   1213     case MOVZ:
   1214       Format(instr, "movz    'rd, 'rs, 'rt");
   1215       break;
   1216     case MOVN:
   1217       Format(instr, "movn    'rd, 'rs, 'rt");
   1218       break;
   1219     case MOVCI:
   1220       if (instr->Bit(16)) {
   1221         Format(instr, "movt    'rd, 'rs, 'bc");
   1222       } else {
   1223         Format(instr, "movf    'rd, 'rs, 'bc");
   1224       }
   1225       break;
   1226     case SELEQZ_S:
   1227       Format(instr, "seleqz    'rd, 'rs, 'rt");
   1228       break;
   1229     case SELNEZ_S:
   1230       Format(instr, "selnez    'rd, 'rs, 'rt");
   1231       break;
   1232     default:
   1233       UNREACHABLE();
   1234   }
   1235 }
   1236 
   1237 
   1238 void Decoder::DecodeTypeRegisterSPECIAL2(Instruction* instr) {
   1239   switch (instr->FunctionFieldRaw()) {
   1240     case MUL:
   1241       Format(instr, "mul     'rd, 'rs, 'rt");
   1242       break;
   1243     case CLZ:
   1244       if (!IsMipsArchVariant(kMips32r6)) {
   1245         Format(instr, "clz     'rd, 'rs");
   1246       }
   1247       break;
   1248     default:
   1249       UNREACHABLE();
   1250   }
   1251 }
   1252 
   1253 
   1254 void Decoder::DecodeTypeRegisterSPECIAL3(Instruction* instr) {
   1255   switch (instr->FunctionFieldRaw()) {
   1256     case INS: {
   1257       if (IsMipsArchVariant(kMips32r2) || IsMipsArchVariant(kMips32r6)) {
   1258         Format(instr, "ins     'rt, 'rs, 'sa, 'ss2");
   1259       } else {
   1260         Unknown(instr);
   1261       }
   1262       break;
   1263     }
   1264     case EXT: {
   1265       if (IsMipsArchVariant(kMips32r2) || IsMipsArchVariant(kMips32r6)) {
   1266         Format(instr, "ext     'rt, 'rs, 'sa, 'ss1");
   1267       } else {
   1268         Unknown(instr);
   1269       }
   1270       break;
   1271     }
   1272     case BSHFL: {
   1273       int sa = instr->SaFieldRaw() >> kSaShift;
   1274       switch (sa) {
   1275         case BITSWAP: {
   1276           if (IsMipsArchVariant(kMips32r6)) {
   1277             Format(instr, "bitswap 'rd, 'rt");
   1278           } else {
   1279             Unknown(instr);
   1280           }
   1281           break;
   1282         }
   1283         case SEB: {
   1284           if (IsMipsArchVariant(kMips32r2) || IsMipsArchVariant(kMips32r6)) {
   1285             Format(instr, "seb     'rd, 'rt");
   1286           } else {
   1287             Unknown(instr);
   1288           }
   1289           break;
   1290         }
   1291         case SEH: {
   1292           if (IsMipsArchVariant(kMips32r2) || IsMipsArchVariant(kMips32r6)) {
   1293             Format(instr, "seh     'rd, 'rt");
   1294           } else {
   1295             Unknown(instr);
   1296           }
   1297           break;
   1298         }
   1299         case WSBH: {
   1300           if (IsMipsArchVariant(kMips32r2) || IsMipsArchVariant(kMips32r6)) {
   1301             Format(instr, "wsbh    'rd, 'rt");
   1302           } else {
   1303             Unknown(instr);
   1304           }
   1305           break;
   1306         }
   1307         default: {
   1308           sa >>= kBp2Bits;
   1309           switch (sa) {
   1310             case ALIGN: {
   1311               if (IsMipsArchVariant(kMips32r6)) {
   1312                 Format(instr, "align  'rd, 'rs, 'rt, 'bp2");
   1313               } else {
   1314                 Unknown(instr);
   1315               }
   1316               break;
   1317             }
   1318             default:
   1319               UNREACHABLE();
   1320               break;
   1321           }
   1322         }
   1323       }
   1324       break;
   1325     }
   1326     default:
   1327       UNREACHABLE();
   1328   }
   1329 }
   1330 
   1331 
   1332 void Decoder::DecodeTypeRegister(Instruction* instr) {
   1333   switch (instr->OpcodeFieldRaw()) {
   1334     case COP1:    // Coprocessor instructions.
   1335       switch (instr->RsFieldRaw()) {
   1336         case BC1:   // bc1 handled in DecodeTypeImmediate.
   1337           UNREACHABLE();
   1338           break;
   1339         case MFC1:
   1340           Format(instr, "mfc1    'rt, 'fs");
   1341           break;
   1342         case MFHC1:
   1343           Format(instr, "mfhc1   'rt, 'fs");
   1344           break;
   1345         case MTC1:
   1346           Format(instr, "mtc1    'rt, 'fs");
   1347           break;
   1348         // These are called "fs" too, although they are not FPU registers.
   1349         case CTC1:
   1350           Format(instr, "ctc1    'rt, 'fs");
   1351           break;
   1352         case CFC1:
   1353           Format(instr, "cfc1    'rt, 'fs");
   1354           break;
   1355         case MTHC1:
   1356           Format(instr, "mthc1   'rt, 'fs");
   1357           break;
   1358         case S:
   1359           DecodeTypeRegisterSRsType(instr);
   1360           break;
   1361         case D:
   1362           DecodeTypeRegisterDRsType(instr);
   1363           break;
   1364         case L:
   1365           DecodeTypeRegisterLRsType(instr);
   1366           break;
   1367         case W:
   1368           DecodeTypeRegisterWRsType(instr);
   1369           break;
   1370         case PS:
   1371           UNIMPLEMENTED_MIPS();
   1372           break;
   1373         default:
   1374           UNREACHABLE();
   1375       }
   1376       break;
   1377     case COP1X:
   1378       switch (instr->FunctionFieldRaw()) {
   1379         case MADD_S:
   1380           Format(instr, "madd.s  'fd, 'fr, 'fs, 'ft");
   1381           break;
   1382         case MADD_D:
   1383           Format(instr, "madd.d  'fd, 'fr, 'fs, 'ft");
   1384           break;
   1385         case MSUB_S:
   1386           Format(instr, "msub.s  'fd, 'fr, 'fs, 'ft");
   1387           break;
   1388         case MSUB_D:
   1389           Format(instr, "msub.d  'fd, 'fr, 'fs, 'ft");
   1390           break;
   1391         default:
   1392           UNREACHABLE();
   1393       }
   1394       break;
   1395     case SPECIAL:
   1396       DecodeTypeRegisterSPECIAL(instr);
   1397       break;
   1398     case SPECIAL2:
   1399       DecodeTypeRegisterSPECIAL2(instr);
   1400       break;
   1401     case SPECIAL3:
   1402       DecodeTypeRegisterSPECIAL3(instr);
   1403       break;
   1404     default:
   1405       UNREACHABLE();
   1406   }
   1407 }
   1408 
   1409 
   1410 void Decoder::DecodeTypeImmediate(Instruction* instr) {
   1411   switch (instr->OpcodeFieldRaw()) {
   1412     case COP1:
   1413       switch (instr->RsFieldRaw()) {
   1414         case BC1:
   1415           if (instr->FBtrueValue()) {
   1416             Format(instr, "bc1t    'bc, 'imm16u -> 'imm16p4s2");
   1417           } else {
   1418             Format(instr, "bc1f    'bc, 'imm16u -> 'imm16p4s2");
   1419           }
   1420           break;
   1421         case BC1EQZ:
   1422           Format(instr, "bc1eqz    'ft, 'imm16u -> 'imm16p4s2");
   1423           break;
   1424         case BC1NEZ:
   1425           Format(instr, "bc1nez    'ft, 'imm16u -> 'imm16p4s2");
   1426           break;
   1427         default:
   1428           UNREACHABLE();
   1429       }
   1430 
   1431       break;  // Case COP1.
   1432     // ------------- REGIMM class.
   1433     case REGIMM:
   1434       switch (instr->RtFieldRaw()) {
   1435         case BLTZ:
   1436           Format(instr, "bltz    'rs, 'imm16u -> 'imm16p4s2");
   1437           break;
   1438         case BLTZAL:
   1439           Format(instr, "bltzal  'rs, 'imm16u -> 'imm16p4s2");
   1440           break;
   1441         case BGEZ:
   1442           Format(instr, "bgez    'rs, 'imm16u -> 'imm16p4s2");
   1443           break;
   1444         case BGEZAL: {
   1445           if (instr->RsValue() == 0)
   1446             Format(instr, "bal     'imm16s -> 'imm16p4s2");
   1447           else
   1448             Format(instr, "bgezal  'rs, 'imm16u -> 'imm16p4s2");
   1449           break;
   1450         }
   1451         case BGEZALL:
   1452           Format(instr, "bgezall 'rs, 'imm16u -> 'imm16p4s2");
   1453           break;
   1454         default:
   1455           UNREACHABLE();
   1456       }
   1457     break;  // Case REGIMM.
   1458     // ------------- Branch instructions.
   1459     case BEQ:
   1460       Format(instr, "beq     'rs, 'rt, 'imm16u -> 'imm16p4s2");
   1461       break;
   1462     case BC:
   1463       Format(instr, "bc      'imm26s -> 'imm26p4s2");
   1464       break;
   1465     case BALC:
   1466       Format(instr, "balc    'imm26s -> 'imm26p4s2");
   1467       break;
   1468     case BNE:
   1469       Format(instr, "bne     'rs, 'rt, 'imm16u -> 'imm16p4s2");
   1470       break;
   1471     case BLEZ:
   1472       if ((instr->RtValue() == 0) && (instr->RsValue() != 0)) {
   1473         Format(instr, "blez    'rs, 'imm16u -> 'imm16p4s2");
   1474       } else if ((instr->RtValue() != instr->RsValue()) &&
   1475                  (instr->RsValue() != 0) && (instr->RtValue() != 0)) {
   1476         Format(instr, "bgeuc   'rs, 'rt, 'imm16u -> 'imm16p4s2");
   1477       } else if ((instr->RtValue() == instr->RsValue()) &&
   1478                  (instr->RtValue() != 0)) {
   1479         Format(instr, "bgezalc 'rs, 'imm16u -> 'imm16p4s2");
   1480       } else if ((instr->RsValue() == 0) && (instr->RtValue() != 0)) {
   1481         Format(instr, "blezalc 'rt, 'imm16u -> 'imm16p4s2");
   1482       } else {
   1483         UNREACHABLE();
   1484       }
   1485       break;
   1486     case BGTZ:
   1487       if ((instr->RtValue() == 0) && (instr->RsValue() != 0)) {
   1488         Format(instr, "bgtz    'rs, 'imm16u -> 'imm16p4s2");
   1489       } else if ((instr->RtValue() != instr->RsValue()) &&
   1490                  (instr->RsValue() != 0) && (instr->RtValue() != 0)) {
   1491         Format(instr, "bltuc   'rs, 'rt, 'imm16u -> 'imm16p4s2");
   1492       } else if ((instr->RtValue() == instr->RsValue()) &&
   1493                  (instr->RtValue() != 0)) {
   1494         Format(instr, "bltzalc 'rt, 'imm16u -> 'imm16p4s2");
   1495       } else if ((instr->RsValue() == 0) && (instr->RtValue() != 0)) {
   1496         Format(instr, "bgtzalc 'rt, 'imm16u -> 'imm16p4s2");
   1497       } else {
   1498         UNREACHABLE();
   1499       }
   1500       break;
   1501     case BLEZL:
   1502       if ((instr->RtValue() == instr->RsValue()) && (instr->RtValue() != 0)) {
   1503         Format(instr, "bgezc    'rt, 'imm16u -> 'imm16p4s2");
   1504       } else if ((instr->RtValue() != instr->RsValue()) &&
   1505                  (instr->RsValue() != 0) && (instr->RtValue() != 0)) {
   1506         Format(instr, "bgec     'rs, 'rt, 'imm16u -> 'imm16p4s2");
   1507       } else if ((instr->RsValue() == 0) && (instr->RtValue() != 0)) {
   1508         Format(instr, "blezc    'rt, 'imm16u -> 'imm16p4s2");
   1509       } else {
   1510         UNREACHABLE();
   1511       }
   1512       break;
   1513     case BGTZL:
   1514       if ((instr->RtValue() == instr->RsValue()) && (instr->RtValue() != 0)) {
   1515         Format(instr, "bltzc    'rt, 'imm16u -> 'imm16p4s2");
   1516       } else if ((instr->RtValue() != instr->RsValue()) &&
   1517                  (instr->RsValue() != 0) && (instr->RtValue() != 0)) {
   1518         Format(instr, "bltc    'rs, 'rt, 'imm16u -> 'imm16p4s2");
   1519       } else if ((instr->RsValue() == 0) && (instr->RtValue() != 0)) {
   1520         Format(instr, "bgtzc    'rt, 'imm16u -> 'imm16p4s2");
   1521       } else {
   1522         UNREACHABLE();
   1523       }
   1524       break;
   1525     case POP66:
   1526       if (instr->RsValue() == JIC) {
   1527         Format(instr, "jic     'rt, 'imm16s");
   1528       } else {
   1529         Format(instr, "beqzc   'rs, 'imm21s -> 'imm21p4s2");
   1530       }
   1531       break;
   1532     case POP76:
   1533       if (instr->RsValue() == JIALC) {
   1534         Format(instr, "jialc   'rt, 'imm16s");
   1535       } else {
   1536         Format(instr, "bnezc   'rs, 'imm21s -> 'imm21p4s2");
   1537       }
   1538       break;
   1539     // ------------- Arithmetic instructions.
   1540     case ADDI:
   1541       if (!IsMipsArchVariant(kMips32r6)) {
   1542         Format(instr, "addi    'rt, 'rs, 'imm16s");
   1543       } else {
   1544         int rs_reg = instr->RsValue();
   1545         int rt_reg = instr->RtValue();
   1546         // Check if BOVC, BEQZALC or BEQC instruction.
   1547         if (rs_reg >= rt_reg) {
   1548           Format(instr, "bovc  'rs, 'rt, 'imm16s -> 'imm16p4s2");
   1549         } else {
   1550           DCHECK(rt_reg > 0);
   1551           if (rs_reg == 0) {
   1552             Format(instr, "beqzalc 'rt, 'imm16s -> 'imm16p4s2");
   1553           } else {
   1554             Format(instr, "beqc    'rs, 'rt, 'imm16s -> 'imm16p4s2");
   1555           }
   1556         }
   1557       }
   1558       break;
   1559     case DADDI:
   1560       if (IsMipsArchVariant(kMips32r6)) {
   1561         int rs_reg = instr->RsValue();
   1562         int rt_reg = instr->RtValue();
   1563         // Check if BNVC, BNEZALC or BNEC instruction.
   1564         if (rs_reg >= rt_reg) {
   1565           Format(instr, "bnvc  'rs, 'rt, 'imm16s -> 'imm16p4s2");
   1566         } else {
   1567           DCHECK(rt_reg > 0);
   1568           if (rs_reg == 0) {
   1569             Format(instr, "bnezalc 'rt, 'imm16s -> 'imm16p4s2");
   1570           } else {
   1571             Format(instr, "bnec  'rs, 'rt, 'imm16s -> 'imm16p4s2");
   1572           }
   1573         }
   1574       }
   1575       break;
   1576     case ADDIU:
   1577       Format(instr, "addiu   'rt, 'rs, 'imm16s");
   1578       break;
   1579     case SLTI:
   1580       Format(instr, "slti    'rt, 'rs, 'imm16s");
   1581       break;
   1582     case SLTIU:
   1583       Format(instr, "sltiu   'rt, 'rs, 'imm16u");
   1584       break;
   1585     case ANDI:
   1586       Format(instr, "andi    'rt, 'rs, 'imm16x");
   1587       break;
   1588     case ORI:
   1589       Format(instr, "ori     'rt, 'rs, 'imm16x");
   1590       break;
   1591     case XORI:
   1592       Format(instr, "xori    'rt, 'rs, 'imm16x");
   1593       break;
   1594     case LUI:
   1595       if (!IsMipsArchVariant(kMips32r6)) {
   1596         Format(instr, "lui     'rt, 'imm16x");
   1597       } else {
   1598         if (instr->RsValue() != 0) {
   1599           Format(instr, "aui     'rt, 'rs, 'imm16x");
   1600         } else {
   1601           Format(instr, "lui     'rt, 'imm16x");
   1602         }
   1603       }
   1604       break;
   1605     // ------------- Memory instructions.
   1606     case LB:
   1607       Format(instr, "lb      'rt, 'imm16s('rs)");
   1608       break;
   1609     case LH:
   1610       Format(instr, "lh      'rt, 'imm16s('rs)");
   1611       break;
   1612     case LWL:
   1613       Format(instr, "lwl     'rt, 'imm16s('rs)");
   1614       break;
   1615     case LW:
   1616       Format(instr, "lw      'rt, 'imm16s('rs)");
   1617       break;
   1618     case LBU:
   1619       Format(instr, "lbu     'rt, 'imm16s('rs)");
   1620       break;
   1621     case LHU:
   1622       Format(instr, "lhu     'rt, 'imm16s('rs)");
   1623       break;
   1624     case LWR:
   1625       Format(instr, "lwr     'rt, 'imm16s('rs)");
   1626       break;
   1627     case PREF:
   1628       Format(instr, "pref    'rt, 'imm16s('rs)");
   1629       break;
   1630     case SB:
   1631       Format(instr, "sb      'rt, 'imm16s('rs)");
   1632       break;
   1633     case SH:
   1634       Format(instr, "sh      'rt, 'imm16s('rs)");
   1635       break;
   1636     case SWL:
   1637       Format(instr, "swl     'rt, 'imm16s('rs)");
   1638       break;
   1639     case SW:
   1640       Format(instr, "sw      'rt, 'imm16s('rs)");
   1641       break;
   1642     case SWR:
   1643       Format(instr, "swr     'rt, 'imm16s('rs)");
   1644       break;
   1645     case LWC1:
   1646       Format(instr, "lwc1    'ft, 'imm16s('rs)");
   1647       break;
   1648     case LDC1:
   1649       Format(instr, "ldc1    'ft, 'imm16s('rs)");
   1650       break;
   1651     case SWC1:
   1652       Format(instr, "swc1    'ft, 'imm16s('rs)");
   1653       break;
   1654     case SDC1:
   1655       Format(instr, "sdc1    'ft, 'imm16s('rs)");
   1656       break;
   1657     case PCREL: {
   1658       int32_t imm21 = instr->Imm21Value();
   1659       // rt field: 5-bits checking
   1660       uint8_t rt = (imm21 >> kImm16Bits);
   1661       switch (rt) {
   1662         case ALUIPC:
   1663           Format(instr, "aluipc  'rs, 'imm16s");
   1664           break;
   1665         case AUIPC:
   1666           Format(instr, "auipc   'rs, 'imm16s");
   1667           break;
   1668         default: {
   1669           // rt field: checking of the most significant 2-bits
   1670           rt = (imm21 >> kImm19Bits);
   1671           switch (rt) {
   1672             case LWPC:
   1673               Format(instr, "lwpc    'rs, 'imm19s");
   1674               break;
   1675             case ADDIUPC:
   1676               Format(instr, "addiupc 'rs, 'imm19s");
   1677               break;
   1678             default:
   1679               UNREACHABLE();
   1680               break;
   1681           }
   1682         }
   1683       }
   1684       break;
   1685     }
   1686     default:
   1687       printf("a 0x%x \n", instr->OpcodeFieldRaw());
   1688       UNREACHABLE();
   1689       break;
   1690   }
   1691 }
   1692 
   1693 
   1694 void Decoder::DecodeTypeJump(Instruction* instr) {
   1695   switch (instr->OpcodeFieldRaw()) {
   1696     case J:
   1697       Format(instr, "j       'imm26x -> 'imm26j");
   1698       break;
   1699     case JAL:
   1700       Format(instr, "jal     'imm26x -> 'imm26j");
   1701       break;
   1702     default:
   1703       UNREACHABLE();
   1704   }
   1705 }
   1706 
   1707 
   1708 // Disassemble the instruction at *instr_ptr into the output buffer.
   1709 int Decoder::InstructionDecode(byte* instr_ptr) {
   1710   Instruction* instr = Instruction::At(instr_ptr);
   1711   // Print raw instruction bytes.
   1712   out_buffer_pos_ += SNPrintF(out_buffer_ + out_buffer_pos_,
   1713                                    "%08x       ",
   1714                                    instr->InstructionBits());
   1715   switch (instr->InstructionType()) {
   1716     case Instruction::kRegisterType: {
   1717       DecodeTypeRegister(instr);
   1718       break;
   1719     }
   1720     case Instruction::kImmediateType: {
   1721       DecodeTypeImmediate(instr);
   1722       break;
   1723     }
   1724     case Instruction::kJumpType: {
   1725       DecodeTypeJump(instr);
   1726       break;
   1727     }
   1728     default: {
   1729       Format(instr, "UNSUPPORTED");
   1730       UNSUPPORTED_MIPS();
   1731     }
   1732   }
   1733   return Instruction::kInstrSize;
   1734 }
   1735 
   1736 
   1737 }  // namespace internal
   1738 }  // namespace v8
   1739 
   1740 
   1741 //------------------------------------------------------------------------------
   1742 
   1743 namespace disasm {
   1744 
   1745 const char* NameConverter::NameOfAddress(byte* addr) const {
   1746   v8::internal::SNPrintF(tmp_buffer_, "%p", static_cast<void*>(addr));
   1747   return tmp_buffer_.start();
   1748 }
   1749 
   1750 
   1751 const char* NameConverter::NameOfConstant(byte* addr) const {
   1752   return NameOfAddress(addr);
   1753 }
   1754 
   1755 
   1756 const char* NameConverter::NameOfCPURegister(int reg) const {
   1757   return v8::internal::Registers::Name(reg);
   1758 }
   1759 
   1760 
   1761 const char* NameConverter::NameOfXMMRegister(int reg) const {
   1762   return v8::internal::FPURegisters::Name(reg);
   1763 }
   1764 
   1765 
   1766 const char* NameConverter::NameOfByteCPURegister(int reg) const {
   1767   UNREACHABLE();  // MIPS does not have the concept of a byte register.
   1768   return "nobytereg";
   1769 }
   1770 
   1771 
   1772 const char* NameConverter::NameInCode(byte* addr) const {
   1773   // The default name converter is called for unknown code. So we will not try
   1774   // to access any memory.
   1775   return "";
   1776 }
   1777 
   1778 
   1779 //------------------------------------------------------------------------------
   1780 
   1781 Disassembler::Disassembler(const NameConverter& converter)
   1782     : converter_(converter) {}
   1783 
   1784 
   1785 Disassembler::~Disassembler() {}
   1786 
   1787 
   1788 int Disassembler::InstructionDecode(v8::internal::Vector<char> buffer,
   1789                                     byte* instruction) {
   1790   v8::internal::Decoder d(converter_, buffer);
   1791   return d.InstructionDecode(instruction);
   1792 }
   1793 
   1794 
   1795 // The MIPS assembler does not currently use constant pools.
   1796 int Disassembler::ConstantPoolSizeAt(byte* instruction) {
   1797   return -1;
   1798 }
   1799 
   1800 
   1801 void Disassembler::Disassemble(FILE* f, byte* begin, byte* end) {
   1802   NameConverter converter;
   1803   Disassembler d(converter);
   1804   for (byte* pc = begin; pc < end;) {
   1805     v8::internal::EmbeddedVector<char, 128> buffer;
   1806     buffer[0] = '\0';
   1807     byte* prev_pc = pc;
   1808     pc += d.InstructionDecode(buffer, pc);
   1809     v8::internal::PrintF(f, "%p    %08x      %s\n", static_cast<void*>(prev_pc),
   1810                          *reinterpret_cast<int32_t*>(prev_pc), buffer.start());
   1811   }
   1812 }
   1813 
   1814 
   1815 #undef UNSUPPORTED
   1816 
   1817 }  // namespace disasm
   1818 
   1819 #endif  // V8_TARGET_ARCH_MIPS
   1820