1/*
2 * Copyright (C) 2012 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include "disassembler_x86.h"
18
19#include <iostream>
20
21#include "base/logging.h"
22#include "base/stringprintf.h"
23#include "thread.h"
24
25namespace art {
26namespace x86 {
27
28DisassemblerX86::DisassemblerX86() {}
29
30size_t DisassemblerX86::Dump(std::ostream& os, const uint8_t* begin) {
31  return DumpInstruction(os, begin);
32}
33
34void DisassemblerX86::Dump(std::ostream& os, const uint8_t* begin, const uint8_t* end) {
35  size_t length = 0;
36  for (const uint8_t* cur = begin; cur < end; cur += length) {
37    length = DumpInstruction(os, cur);
38  }
39}
40
41static const char* gReg8Names[]  = { "al", "cl", "dl", "bl", "ah", "ch", "dh", "bh" };
42static const char* gReg16Names[] = { "ax", "cx", "dx", "bx", "sp", "bp", "si", "di" };
43static const char* gReg32Names[] = { "eax", "ecx", "edx", "ebx", "esp", "ebp", "esi", "edi" };
44
45static void DumpReg0(std::ostream& os, uint8_t /*rex*/, size_t reg,
46                     bool byte_operand, uint8_t size_override) {
47  DCHECK_LT(reg, 8u);
48  // TODO: combine rex into size
49  size_t size = byte_operand ? 1 : (size_override == 0x66 ? 2 : 4);
50  switch (size) {
51    case 1: os << gReg8Names[reg]; break;
52    case 2: os << gReg16Names[reg]; break;
53    case 4: os << gReg32Names[reg]; break;
54    default: LOG(FATAL) << "unexpected size " << size;
55  }
56}
57
58enum RegFile { GPR, MMX, SSE };
59
60static void DumpReg(std::ostream& os, uint8_t rex, uint8_t reg,
61                    bool byte_operand, uint8_t size_override, RegFile reg_file) {
62  size_t reg_num = reg;  // TODO: combine with REX.R on 64bit
63  if (reg_file == GPR) {
64    DumpReg0(os, rex, reg_num, byte_operand, size_override);
65  } else if (reg_file == SSE) {
66    os << "xmm" << reg_num;
67  } else {
68    os << "mm" << reg_num;
69  }
70}
71
72static void DumpBaseReg(std::ostream& os, uint8_t rex, uint8_t reg) {
73  size_t reg_num = reg;  // TODO: combine with REX.B on 64bit
74  DumpReg0(os, rex, reg_num, false, 0);
75}
76
77static void DumpIndexReg(std::ostream& os, uint8_t rex, uint8_t reg) {
78  int reg_num = reg;  // TODO: combine with REX.X on 64bit
79  DumpReg0(os, rex, reg_num, false, 0);
80}
81
82enum SegmentPrefix {
83  kCs = 0x2e,
84  kSs = 0x36,
85  kDs = 0x3e,
86  kEs = 0x26,
87  kFs = 0x64,
88  kGs = 0x65,
89};
90
91static void DumpSegmentOverride(std::ostream& os, uint8_t segment_prefix) {
92  switch (segment_prefix) {
93    case kCs: os << "cs:"; break;
94    case kSs: os << "ss:"; break;
95    case kDs: os << "ds:"; break;
96    case kEs: os << "es:"; break;
97    case kFs: os << "fs:"; break;
98    case kGs: os << "gs:"; break;
99    default: break;
100  }
101}
102
103size_t DisassemblerX86::DumpInstruction(std::ostream& os, const uint8_t* instr) {
104  const uint8_t* begin_instr = instr;
105  bool have_prefixes = true;
106  uint8_t prefix[4] = {0, 0, 0, 0};
107  const char** modrm_opcodes = NULL;
108  do {
109    switch (*instr) {
110        // Group 1 - lock and repeat prefixes:
111      case 0xF0:
112      case 0xF2:
113      case 0xF3:
114        prefix[0] = *instr;
115        break;
116        // Group 2 - segment override prefixes:
117      case kCs:
118      case kSs:
119      case kDs:
120      case kEs:
121      case kFs:
122      case kGs:
123        prefix[1] = *instr;
124        break;
125        // Group 3 - operand size override:
126      case 0x66:
127        prefix[2] = *instr;
128        break;
129        // Group 4 - address size override:
130      case 0x67:
131        prefix[3] = *instr;
132        break;
133      default:
134        have_prefixes = false;
135        break;
136    }
137    if (have_prefixes) {
138      instr++;
139    }
140  } while (have_prefixes);
141  uint8_t rex = (*instr >= 0x40 && *instr <= 0x4F) ? *instr : 0;
142  bool has_modrm = false;
143  bool reg_is_opcode = false;
144  size_t immediate_bytes = 0;
145  size_t branch_bytes = 0;
146  std::ostringstream opcode;
147  bool store = false;  // stores to memory (ie rm is on the left)
148  bool load = false;  // loads from memory (ie rm is on the right)
149  bool byte_operand = false;
150  bool ax = false;  // implicit use of ax
151  bool cx = false;  // implicit use of cx
152  bool reg_in_opcode = false;  // low 3-bits of opcode encode register parameter
153  bool no_ops = false;
154  RegFile src_reg_file = GPR;
155  RegFile dst_reg_file = GPR;
156  switch (*instr) {
157#define DISASSEMBLER_ENTRY(opname, \
158                     rm8_r8, rm32_r32, \
159                     r8_rm8, r32_rm32, \
160                     ax8_i8, ax32_i32) \
161  case rm8_r8:   opcode << #opname; store = true; has_modrm = true; byte_operand = true; break; \
162  case rm32_r32: opcode << #opname; store = true; has_modrm = true; break; \
163  case r8_rm8:   opcode << #opname; load = true; has_modrm = true; byte_operand = true; break; \
164  case r32_rm32: opcode << #opname; load = true; has_modrm = true; break; \
165  case ax8_i8:   opcode << #opname; ax = true; immediate_bytes = 1; byte_operand = true; break; \
166  case ax32_i32: opcode << #opname; ax = true; immediate_bytes = 4; break;
167
168DISASSEMBLER_ENTRY(add,
169  0x00 /* RegMem8/Reg8 */,     0x01 /* RegMem32/Reg32 */,
170  0x02 /* Reg8/RegMem8 */,     0x03 /* Reg32/RegMem32 */,
171  0x04 /* Rax8/imm8 opcode */, 0x05 /* Rax32/imm32 */)
172DISASSEMBLER_ENTRY(or,
173  0x08 /* RegMem8/Reg8 */,     0x09 /* RegMem32/Reg32 */,
174  0x0A /* Reg8/RegMem8 */,     0x0B /* Reg32/RegMem32 */,
175  0x0C /* Rax8/imm8 opcode */, 0x0D /* Rax32/imm32 */)
176DISASSEMBLER_ENTRY(adc,
177  0x10 /* RegMem8/Reg8 */,     0x11 /* RegMem32/Reg32 */,
178  0x12 /* Reg8/RegMem8 */,     0x13 /* Reg32/RegMem32 */,
179  0x14 /* Rax8/imm8 opcode */, 0x15 /* Rax32/imm32 */)
180DISASSEMBLER_ENTRY(sbb,
181  0x18 /* RegMem8/Reg8 */,     0x19 /* RegMem32/Reg32 */,
182  0x1A /* Reg8/RegMem8 */,     0x1B /* Reg32/RegMem32 */,
183  0x1C /* Rax8/imm8 opcode */, 0x1D /* Rax32/imm32 */)
184DISASSEMBLER_ENTRY(and,
185  0x20 /* RegMem8/Reg8 */,     0x21 /* RegMem32/Reg32 */,
186  0x22 /* Reg8/RegMem8 */,     0x23 /* Reg32/RegMem32 */,
187  0x24 /* Rax8/imm8 opcode */, 0x25 /* Rax32/imm32 */)
188DISASSEMBLER_ENTRY(sub,
189  0x28 /* RegMem8/Reg8 */,     0x29 /* RegMem32/Reg32 */,
190  0x2A /* Reg8/RegMem8 */,     0x2B /* Reg32/RegMem32 */,
191  0x2C /* Rax8/imm8 opcode */, 0x2D /* Rax32/imm32 */)
192DISASSEMBLER_ENTRY(xor,
193  0x30 /* RegMem8/Reg8 */,     0x31 /* RegMem32/Reg32 */,
194  0x32 /* Reg8/RegMem8 */,     0x33 /* Reg32/RegMem32 */,
195  0x34 /* Rax8/imm8 opcode */, 0x35 /* Rax32/imm32 */)
196DISASSEMBLER_ENTRY(cmp,
197  0x38 /* RegMem8/Reg8 */,     0x39 /* RegMem32/Reg32 */,
198  0x3A /* Reg8/RegMem8 */,     0x3B /* Reg32/RegMem32 */,
199  0x3C /* Rax8/imm8 opcode */, 0x3D /* Rax32/imm32 */)
200
201#undef DISASSEMBLER_ENTRY
202  case 0x50: case 0x51: case 0x52: case 0x53: case 0x54: case 0x55: case 0x56: case 0x57:
203    opcode << "push";
204    reg_in_opcode = true;
205    break;
206  case 0x58: case 0x59: case 0x5A: case 0x5B: case 0x5C: case 0x5D: case 0x5E: case 0x5F:
207    opcode << "pop";
208    reg_in_opcode = true;
209    break;
210  case 0x68: opcode << "push"; immediate_bytes = 4; break;
211  case 0x6A: opcode << "push"; immediate_bytes = 1; break;
212  case 0x70: case 0x71: case 0x72: case 0x73: case 0x74: case 0x75: case 0x76: case 0x77:
213  case 0x78: case 0x79: case 0x7A: case 0x7B: case 0x7C: case 0x7D: case 0x7E: case 0x7F:
214    static const char* condition_codes[] =
215    {"o", "no", "b/nae/c", "nb/ae/nc", "z/eq",  "nz/ne", "be/na", "nbe/a",
216     "s", "ns", "p/pe",    "np/po",    "l/nge", "nl/ge", "le/ng", "nle/g"
217    };
218    opcode << "j" << condition_codes[*instr & 0xF];
219    branch_bytes = 1;
220    break;
221  case 0x88: opcode << "mov"; store = true; has_modrm = true; byte_operand = true; break;
222  case 0x89: opcode << "mov"; store = true; has_modrm = true; break;
223  case 0x8A: opcode << "mov"; load = true; has_modrm = true; byte_operand = true; break;
224  case 0x8B: opcode << "mov"; load = true; has_modrm = true; break;
225
226  case 0x0F:  // 2 byte extended opcode
227    instr++;
228    switch (*instr) {
229      case 0x10: case 0x11:
230        if (prefix[0] == 0xF2) {
231          opcode << "movsd";
232          prefix[0] = 0;  // clear prefix now it's served its purpose as part of the opcode
233        } else if (prefix[0] == 0xF3) {
234          opcode << "movss";
235          prefix[0] = 0;  // clear prefix now it's served its purpose as part of the opcode
236        } else if (prefix[2] == 0x66) {
237          opcode << "movupd";
238          prefix[2] = 0;  // clear prefix now it's served its purpose as part of the opcode
239        } else {
240          opcode << "movups";
241        }
242        has_modrm = true;
243        src_reg_file = dst_reg_file = SSE;
244        load = *instr == 0x10;
245        store = !load;
246        break;
247      case 0x2A:
248        if (prefix[2] == 0x66) {
249          opcode << "cvtpi2pd";
250          prefix[2] = 0;  // clear prefix now it's served its purpose as part of the opcode
251        } else if (prefix[0] == 0xF2) {
252          opcode << "cvtsi2sd";
253          prefix[0] = 0;  // clear prefix now it's served its purpose as part of the opcode
254        } else if (prefix[0] == 0xF3) {
255          opcode << "cvtsi2ss";
256          prefix[0] = 0;  // clear prefix now it's served its purpose as part of the opcode
257        } else {
258          opcode << "cvtpi2ps";
259        }
260        load = true;
261        has_modrm = true;
262        dst_reg_file = SSE;
263        break;
264      case 0x2C:
265        if (prefix[2] == 0x66) {
266          opcode << "cvttpd2pi";
267          prefix[2] = 0;  // clear prefix now it's served its purpose as part of the opcode
268        } else if (prefix[0] == 0xF2) {
269          opcode << "cvttsd2si";
270          prefix[0] = 0;  // clear prefix now it's served its purpose as part of the opcode
271        } else if (prefix[0] == 0xF3) {
272          opcode << "cvttss2si";
273          prefix[0] = 0;  // clear prefix now it's served its purpose as part of the opcode
274        } else {
275          opcode << "cvttps2pi";
276        }
277        load = true;
278        has_modrm = true;
279        src_reg_file = SSE;
280        break;
281      case 0x2D:
282        if (prefix[2] == 0x66) {
283          opcode << "cvtpd2pi";
284          prefix[2] = 0;  // clear prefix now it's served its purpose as part of the opcode
285        } else if (prefix[0] == 0xF2) {
286          opcode << "cvtsd2si";
287          prefix[0] = 0;  // clear prefix now it's served its purpose as part of the opcode
288        } else if (prefix[0] == 0xF3) {
289          opcode << "cvtss2si";
290          prefix[0] = 0;  // clear prefix now it's served its purpose as part of the opcode
291        } else {
292          opcode << "cvtps2pi";
293        }
294        load = true;
295        has_modrm = true;
296        src_reg_file = SSE;
297        break;
298      case 0x2E:
299        opcode << "u";
300        // FALLTHROUGH
301      case 0x2F:
302        if (prefix[2] == 0x66) {
303          opcode << "comisd";
304          prefix[2] = 0;  // clear prefix now it's served its purpose as part of the opcode
305        } else {
306          opcode << "comiss";
307        }
308        has_modrm = true;
309        load = true;
310        src_reg_file = dst_reg_file = SSE;
311        break;
312      case 0x38:  // 3 byte extended opcode
313        opcode << StringPrintf("unknown opcode '0F 38 %02X'", *instr);
314        break;
315      case 0x3A:  // 3 byte extended opcode
316        opcode << StringPrintf("unknown opcode '0F 3A %02X'", *instr);
317        break;
318      case 0x50: case 0x51: case 0x52: case 0x53: case 0x54: case 0x55: case 0x56: case 0x57:
319      case 0x58: case 0x59: case 0x5C: case 0x5D: case 0x5E: case 0x5F: {
320        switch (*instr) {
321          case 0x50: opcode << "movmsk"; break;
322          case 0x51: opcode << "sqrt"; break;
323          case 0x52: opcode << "rsqrt"; break;
324          case 0x53: opcode << "rcp"; break;
325          case 0x54: opcode << "and"; break;
326          case 0x55: opcode << "andn"; break;
327          case 0x56: opcode << "or"; break;
328          case 0x57: opcode << "xor"; break;
329          case 0x58: opcode << "add"; break;
330          case 0x59: opcode << "mul"; break;
331          case 0x5C: opcode << "sub"; break;
332          case 0x5D: opcode << "min"; break;
333          case 0x5E: opcode << "div"; break;
334          case 0x5F: opcode << "max"; break;
335          default: LOG(FATAL) << "Unreachable";
336        }
337        if (prefix[2] == 0x66) {
338          opcode << "pd";
339          prefix[2] = 0;  // clear prefix now it's served its purpose as part of the opcode
340        } else if (prefix[0] == 0xF2) {
341          opcode << "sd";
342          prefix[0] = 0;  // clear prefix now it's served its purpose as part of the opcode
343        } else if (prefix[0] == 0xF3) {
344          opcode << "ss";
345          prefix[0] = 0;  // clear prefix now it's served its purpose as part of the opcode
346        } else {
347          opcode << "ps";
348        }
349        load = true;
350        has_modrm = true;
351        src_reg_file = dst_reg_file = SSE;
352        break;
353      }
354      case 0x5A:
355        if (prefix[2] == 0x66) {
356          opcode << "cvtpd2ps";
357          prefix[2] = 0;  // clear prefix now it's served its purpose as part of the opcode
358        } else if (prefix[0] == 0xF2) {
359          opcode << "cvtsd2ss";
360          prefix[0] = 0;  // clear prefix now it's served its purpose as part of the opcode
361        } else if (prefix[0] == 0xF3) {
362          opcode << "cvtss2sd";
363          prefix[0] = 0;  // clear prefix now it's served its purpose as part of the opcode
364        } else {
365          opcode << "cvtps2pd";
366        }
367        load = true;
368        has_modrm = true;
369        src_reg_file = dst_reg_file = SSE;
370        break;
371      case 0x5B:
372        if (prefix[2] == 0x66) {
373          opcode << "cvtps2dq";
374          prefix[2] = 0;  // clear prefix now it's served its purpose as part of the opcode
375        } else if (prefix[0] == 0xF2) {
376          opcode << "bad opcode F2 0F 5B";
377        } else if (prefix[0] == 0xF3) {
378          opcode << "cvttps2dq";
379          prefix[0] = 0;  // clear prefix now it's served its purpose as part of the opcode
380        } else {
381          opcode << "cvtdq2ps";
382        }
383        load = true;
384        has_modrm = true;
385        src_reg_file = dst_reg_file = SSE;
386        break;
387      case 0x6E:
388        if (prefix[2] == 0x66) {
389          dst_reg_file = SSE;
390          prefix[2] = 0;  // clear prefix now it's served its purpose as part of the opcode
391        } else {
392          dst_reg_file = MMX;
393        }
394        opcode << "movd";
395        load = true;
396        has_modrm = true;
397        break;
398      case 0x6F:
399        if (prefix[2] == 0x66) {
400          dst_reg_file = SSE;
401          opcode << "movdqa";
402          prefix[2] = 0;  // clear prefix now it's served its purpose as part of the opcode
403        } else if (prefix[0] == 0xF3) {
404          dst_reg_file = SSE;
405          opcode << "movdqu";
406          prefix[0] = 0;  // clear prefix now it's served its purpose as part of the opcode
407        } else {
408          dst_reg_file = MMX;
409          opcode << "movq";
410        }
411        load = true;
412        has_modrm = true;
413        break;
414      case 0x71:
415        if (prefix[2] == 0x66) {
416          dst_reg_file = SSE;
417          prefix[2] = 0;  // clear prefix now it's served its purpose as part of the opcode
418        } else {
419          dst_reg_file = MMX;
420        }
421        static const char* x71_opcodes[] = {"unknown-71", "unknown-71", "psrlw", "unknown-71", "psraw", "unknown-71", "psllw", "unknown-71"};
422        modrm_opcodes = x71_opcodes;
423        reg_is_opcode = true;
424        has_modrm = true;
425        store = true;
426        immediate_bytes = 1;
427        break;
428      case 0x72:
429        if (prefix[2] == 0x66) {
430          dst_reg_file = SSE;
431          prefix[2] = 0;  // clear prefix now it's served its purpose as part of the opcode
432        } else {
433          dst_reg_file = MMX;
434        }
435        static const char* x72_opcodes[] = {"unknown-72", "unknown-72", "psrld", "unknown-72", "psrad", "unknown-72", "pslld", "unknown-72"};
436        modrm_opcodes = x72_opcodes;
437        reg_is_opcode = true;
438        has_modrm = true;
439        store = true;
440        immediate_bytes = 1;
441        break;
442      case 0x73:
443        if (prefix[2] == 0x66) {
444          dst_reg_file = SSE;
445          prefix[2] = 0;  // clear prefix now it's served its purpose as part of the opcode
446        } else {
447          dst_reg_file = MMX;
448        }
449        static const char* x73_opcodes[] = {"unknown-73", "unknown-73", "psrlq", "unknown-73", "unknown-73", "unknown-73", "psllq", "unknown-73"};
450        modrm_opcodes = x73_opcodes;
451        reg_is_opcode = true;
452        has_modrm = true;
453        store = true;
454        immediate_bytes = 1;
455        break;
456      case 0x7E:
457        if (prefix[2] == 0x66) {
458          src_reg_file = SSE;
459          prefix[2] = 0;  // clear prefix now it's served its purpose as part of the opcode
460        } else {
461          src_reg_file = MMX;
462        }
463        opcode << "movd";
464        has_modrm = true;
465        store = true;
466        break;
467      case 0x80: case 0x81: case 0x82: case 0x83: case 0x84: case 0x85: case 0x86: case 0x87:
468      case 0x88: case 0x89: case 0x8A: case 0x8B: case 0x8C: case 0x8D: case 0x8E: case 0x8F:
469        opcode << "j" << condition_codes[*instr & 0xF];
470        branch_bytes = 4;
471        break;
472      case 0x90: case 0x91: case 0x92: case 0x93: case 0x94: case 0x95: case 0x96: case 0x97:
473      case 0x98: case 0x99: case 0x9A: case 0x9B: case 0x9C: case 0x9D: case 0x9E: case 0x9F:
474        opcode << "set" << condition_codes[*instr & 0xF];
475        modrm_opcodes = NULL;
476        reg_is_opcode = true;
477        has_modrm = true;
478        store = true;
479        break;
480      case 0xAE:
481        if (prefix[0] == 0xF3) {
482          prefix[0] = 0;  // clear prefix now it's served its purpose as part of the opcode
483          static const char* xAE_opcodes[] = {"rdfsbase", "rdgsbase", "wrfsbase", "wrgsbase", "unknown-AE", "unknown-AE", "unknown-AE", "unknown-AE"};
484          modrm_opcodes = xAE_opcodes;
485          reg_is_opcode = true;
486          has_modrm = true;
487          uint8_t reg_or_opcode = (instr[1] >> 3) & 7;
488          switch (reg_or_opcode) {
489            case 0:
490              prefix[1] = kFs;
491              load = true;
492              break;
493            case 1:
494              prefix[1] = kGs;
495              load = true;
496              break;
497            case 2:
498              prefix[1] = kFs;
499              store = true;
500              break;
501            case 3:
502              prefix[1] = kGs;
503              store = true;
504              break;
505            default:
506              load = true;
507              break;
508          }
509        } else {
510          static const char* xAE_opcodes[] = {"unknown-AE", "unknown-AE", "unknown-AE", "unknown-AE", "unknown-AE", "lfence", "mfence", "sfence"};
511          modrm_opcodes = xAE_opcodes;
512          reg_is_opcode = true;
513          has_modrm = true;
514          load = true;
515          no_ops = true;
516        }
517        break;
518      case 0xB1: opcode << "cmpxchg"; has_modrm = true; store = true; break;
519      case 0xB6: opcode << "movzxb"; has_modrm = true; load = true; break;
520      case 0xB7: opcode << "movzxw"; has_modrm = true; load = true; break;
521      case 0xBE: opcode << "movsxb"; has_modrm = true; load = true; break;
522      case 0xBF: opcode << "movsxw"; has_modrm = true; load = true; break;
523      default:
524        opcode << StringPrintf("unknown opcode '0F %02X'", *instr);
525        break;
526    }
527    break;
528  case 0x80: case 0x81: case 0x82: case 0x83:
529    static const char* x80_opcodes[] = {"add", "or", "adc", "sbb", "and", "sub", "xor", "cmp"};
530    modrm_opcodes = x80_opcodes;
531    has_modrm = true;
532    reg_is_opcode = true;
533    store = true;
534    byte_operand = (*instr & 1) == 0;
535    immediate_bytes = *instr == 0x81 ? 4 : 1;
536    break;
537  case 0x84: case 0x85:
538    opcode << "test";
539    has_modrm = true;
540    load = true;
541    byte_operand = (*instr & 1) == 0;
542    break;
543  case 0x8D:
544    opcode << "lea";
545    has_modrm = true;
546    load = true;
547    break;
548  case 0x8F:
549    opcode << "pop";
550    has_modrm = true;
551    reg_is_opcode = true;
552    store = true;
553    break;
554  case 0xB0: case 0xB1: case 0xB2: case 0xB3: case 0xB4: case 0xB5: case 0xB6: case 0xB7:
555    opcode << "mov";
556    immediate_bytes = 1;
557    reg_in_opcode = true;
558    break;
559  case 0xB8: case 0xB9: case 0xBA: case 0xBB: case 0xBC: case 0xBD: case 0xBE: case 0xBF:
560    opcode << "mov";
561    immediate_bytes = 4;
562    reg_in_opcode = true;
563    break;
564  case 0xC0: case 0xC1:
565  case 0xD0: case 0xD1: case 0xD2: case 0xD3:
566    static const char* shift_opcodes[] =
567        {"rol", "ror", "rcl", "rcr", "shl", "shr", "unknown-shift", "sar"};
568    modrm_opcodes = shift_opcodes;
569    has_modrm = true;
570    reg_is_opcode = true;
571    store = true;
572    immediate_bytes = ((*instr & 0xf0) == 0xc0) ? 1 : 0;
573    cx = (*instr == 0xD2) || (*instr == 0xD3);
574    byte_operand = (*instr == 0xC0);
575    break;
576  case 0xC3: opcode << "ret"; break;
577  case 0xC7:
578    static const char* c7_opcodes[] = {"mov", "unknown-c7", "unknown-c7", "unknown-c7", "unknown-c7", "unknown-c7", "unknown-c7", "unknown-c7"};
579    modrm_opcodes = c7_opcodes;
580    store = true;
581    immediate_bytes = 4;
582    has_modrm = true;
583    reg_is_opcode = true;
584    break;
585  case 0xCC: opcode << "int 3"; break;
586  case 0xE8: opcode << "call"; branch_bytes = 4; break;
587  case 0xE9: opcode << "jmp"; branch_bytes = 4; break;
588  case 0xEB: opcode << "jmp"; branch_bytes = 1; break;
589  case 0xF5: opcode << "cmc"; break;
590  case 0xF6: case 0xF7:
591    static const char* f7_opcodes[] = {"test", "unknown-f7", "not", "neg", "mul edx:eax, eax *", "imul edx:eax, eax *", "div edx:eax, edx:eax /", "idiv edx:eax, edx:eax /"};
592    modrm_opcodes = f7_opcodes;
593    has_modrm = true;
594    reg_is_opcode = true;
595    store = true;
596    immediate_bytes = ((instr[1] & 0x38) == 0) ? 1 : 0;
597    break;
598  case 0xFF:
599    static const char* ff_opcodes[] = {"inc", "dec", "call", "call", "jmp", "jmp", "push", "unknown-ff"};
600    modrm_opcodes = ff_opcodes;
601    has_modrm = true;
602    reg_is_opcode = true;
603    load = true;
604    break;
605  default:
606    opcode << StringPrintf("unknown opcode '%02X'", *instr);
607    break;
608  }
609  std::ostringstream args;
610  if (reg_in_opcode) {
611    DCHECK(!has_modrm);
612    DumpReg(args, rex, *instr & 0x7, false, prefix[2], GPR);
613  }
614  instr++;
615  uint32_t address_bits = 0;
616  if (has_modrm) {
617    uint8_t modrm = *instr;
618    instr++;
619    uint8_t mod = modrm >> 6;
620    uint8_t reg_or_opcode = (modrm >> 3) & 7;
621    uint8_t rm = modrm & 7;
622    std::ostringstream address;
623    if (mod == 0 && rm == 5) {  // fixed address
624      address_bits = *reinterpret_cast<const uint32_t*>(instr);
625      address << StringPrintf("[0x%x]", address_bits);
626      instr += 4;
627    } else if (rm == 4 && mod != 3) {  // SIB
628      uint8_t sib = *instr;
629      instr++;
630      uint8_t ss = (sib >> 6) & 3;
631      uint8_t index = (sib >> 3) & 7;
632      uint8_t base = sib & 7;
633      address << "[";
634      if (base != 5 || mod != 0) {
635        DumpBaseReg(address, rex, base);
636        if (index != 4) {
637          address << " + ";
638        }
639      }
640      if (index != 4) {
641        DumpIndexReg(address, rex, index);
642        if (ss != 0) {
643          address << StringPrintf(" * %d", 1 << ss);
644        }
645      }
646      if (mod == 1) {
647        address << StringPrintf(" + %d", *reinterpret_cast<const int8_t*>(instr));
648        instr++;
649      } else if (mod == 2) {
650        address << StringPrintf(" + %d", *reinterpret_cast<const int32_t*>(instr));
651        instr += 4;
652      }
653      address << "]";
654    } else {
655      if (mod == 3) {
656        if (!no_ops) {
657          DumpReg(address, rex, rm, byte_operand, prefix[2], load ? src_reg_file : dst_reg_file);
658        }
659      } else {
660        address << "[";
661        DumpBaseReg(address, rex, rm);
662        if (mod == 1) {
663          address << StringPrintf(" + %d", *reinterpret_cast<const int8_t*>(instr));
664          instr++;
665        } else if (mod == 2) {
666          address << StringPrintf(" + %d", *reinterpret_cast<const int32_t*>(instr));
667          instr += 4;
668        }
669        address << "]";
670      }
671    }
672
673    if (reg_is_opcode && modrm_opcodes != NULL) {
674      opcode << modrm_opcodes[reg_or_opcode];
675    }
676    if (load) {
677      if (!reg_is_opcode) {
678        DumpReg(args, rex, reg_or_opcode, byte_operand, prefix[2], dst_reg_file);
679        args << ", ";
680      }
681      DumpSegmentOverride(args, prefix[1]);
682      args << address.str();
683    } else {
684      DCHECK(store);
685      DumpSegmentOverride(args, prefix[1]);
686      args << address.str();
687      if (!reg_is_opcode) {
688        args << ", ";
689        DumpReg(args, rex, reg_or_opcode, byte_operand, prefix[2], src_reg_file);
690      }
691    }
692  }
693  if (ax) {
694    // If this opcode implicitly uses ax, ax is always the first arg.
695    DumpReg(args, rex, 0 /* EAX */, byte_operand, prefix[2], GPR);
696  }
697  if (cx) {
698    args << ", ";
699    DumpReg(args, rex, 1 /* ECX */, true, prefix[2], GPR);
700  }
701  if (immediate_bytes > 0) {
702    if (has_modrm || reg_in_opcode || ax || cx) {
703      args << ", ";
704    }
705    if (immediate_bytes == 1) {
706      args << StringPrintf("%d", *reinterpret_cast<const int8_t*>(instr));
707      instr++;
708    } else {
709      CHECK_EQ(immediate_bytes, 4u);
710      args << StringPrintf("%d", *reinterpret_cast<const int32_t*>(instr));
711      instr += 4;
712    }
713  } else if (branch_bytes > 0) {
714    DCHECK(!has_modrm);
715    int32_t displacement;
716    if (branch_bytes == 1) {
717      displacement = *reinterpret_cast<const int8_t*>(instr);
718      instr++;
719    } else {
720      CHECK_EQ(branch_bytes, 4u);
721      displacement = *reinterpret_cast<const int32_t*>(instr);
722      instr += 4;
723    }
724    args << StringPrintf("%+d (%p)", displacement, instr + displacement);
725  }
726  if (prefix[1] == kFs) {
727    args << "  ; ";
728    Thread::DumpThreadOffset(args, address_bits, 4);
729  }
730  std::stringstream hex;
731  for (size_t i = 0; begin_instr + i < instr; ++i) {
732    hex << StringPrintf("%02X", begin_instr[i]);
733  }
734  std::stringstream prefixed_opcode;
735  switch (prefix[0]) {
736    case 0xF0: prefixed_opcode << "lock "; break;
737    case 0xF2: prefixed_opcode << "repne "; break;
738    case 0xF3: prefixed_opcode << "repe "; break;
739    case 0: break;
740    default: LOG(FATAL) << "Unreachable";
741  }
742  prefixed_opcode << opcode.str();
743  os << StringPrintf("%p: %22s    \t%-7s ", begin_instr, hex.str().c_str(),
744                     prefixed_opcode.str().c_str())
745     << args.str() << '\n';
746  return instr - begin_instr;
747}  // NOLINT(readability/fn_size)
748
749}  // namespace x86
750}  // namespace art
751