1 /*
2 * Copyright 2002-2003 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 package sun.jvm.hotspot.asm.x86;
26
27 import sun.jvm.hotspot.asm.*;
28
29 // basic instruction decoder class
30 public class InstructionDecoder implements /* imports */ X86Opcodes , RTLDataTypes, RTLOperations {
31
32 protected String name;
33 protected int addrMode1;
34 protected int operandType1;
35 protected int addrMode2;
36 protected int operandType2;
37 protected int addrMode3;
38 protected int operandType3;
39
40 private int mod;
41 private int regOrOpcode;
42 private int rm;
43 protected int prefixes;
44
45 protected int byteIndex;
46 protected int instrStartIndex;
47
48 public InstructionDecoder(String name) {
49 this.name = name;
50 this.operandType1 = INVALID_OPERANDTYPE;
51 this.operandType2 = INVALID_OPERANDTYPE;
52 this.operandType3 = INVALID_OPERANDTYPE;
53 this.addrMode1 = INVALID_ADDRMODE;
54 this.addrMode2 = INVALID_ADDRMODE;
55 this.addrMode3 = INVALID_ADDRMODE;
56 }
57 public InstructionDecoder(String name, int addrMode1, int operandType1) {
58 this(name);
59 this.addrMode1 = addrMode1;
60 this.operandType1 = operandType1;
61 }
62 public InstructionDecoder(String name, int addrMode1, int operandType1, int addrMode2, int operandType2) {
63 this(name, addrMode1, operandType1);
64 this.addrMode2 = addrMode2;
65 this.operandType2 = operandType2;
66 }
67 public InstructionDecoder(String name, int addrMode1, int operandType1, int addrMode2, int operandType2,
68 int addrMode3, int operandType3) {
69 this(name, addrMode1, operandType1, addrMode2, operandType2);
70 this.addrMode3 = addrMode3;
71 this.operandType3 = operandType3;
72 }
73 // "operand1"
74 protected Operand getOperand1(byte[] bytesArray, boolean operandSize, boolean addrSize) {
75 if( (addrMode1 != INVALID_ADDRMODE) && (operandType1 != INVALID_OPERANDTYPE) )
76 return getOperand(bytesArray, addrMode1, operandType1, operandSize, addrSize);
77 else
78 return null;
79 }
80
81 // "operand2"
82 protected Operand getOperand2(byte[] bytesArray, boolean operandSize, boolean addrSize) {
83 if( (addrMode2 != INVALID_ADDRMODE) && (operandType2 != INVALID_OPERANDTYPE) )
84 return getOperand(bytesArray, addrMode2, operandType2, operandSize, addrSize);
85 else
86 return null;
87 }
88
89 // "operand3"
90 protected Operand getOperand3(byte[] bytesArray, boolean operandSize, boolean addrSize) {
91 if( (addrMode3 != INVALID_ADDRMODE) && (operandType3 != INVALID_OPERANDTYPE) )
92 return getOperand(bytesArray, addrMode3, operandType3, operandSize, addrSize);
93 else
94 return null;
95 }
96
97 static int readInt32(byte[] bytesArray, int index) {
98 int ret = 0;
99 ret = readByte(bytesArray, index);
100 ret |= readByte(bytesArray, index+1) << 8;
101 ret |= readByte(bytesArray, index+2) << 16;
102 ret |= readByte(bytesArray, index+3) << 24;
103 return ret;
104 }
105 static int readInt16(byte[] bytesArray, int index) {
106 int ret = 0;
107 ret = readByte(bytesArray, index);
108 ret |= readByte(bytesArray, index+1) << 8;
109 return ret;
110 }
111 static int readByte(byte[] bytesArray, int index) {
112 int ret = 0;
113 if (index < bytesArray.length) {
114 ret = (int)bytesArray[index];
115 ret = ret & 0xff;
116 }
117 return ret;
118 }
119 private boolean isModRMPresent(int addrMode) {
120 if( (addrMode == ADDR_E) || (addrMode == ADDR_G) || (addrMode == ADDR_FPREG) || (addrMode == ADDR_Q) || (addrMode == ADDR_W) )
121 return true;
122 else
123 return false;
124 }
125 public int getCurrentIndex() {
126 return byteIndex;
127 }
128
129 public Instruction decode(byte[] bytesArray, int index, int instrStartIndex, int segmentOverride, int prefixes, X86InstructionFactory factory) {
130 this.byteIndex = index;
131 this.instrStartIndex = instrStartIndex;
132 this.prefixes = prefixes;
133 boolean operandSize; //operand-size prefix
134 boolean addrSize; //address-size prefix
135 if ( ( (prefixes & PREFIX_DATA) ^ segmentOverride ) == 1)
136 operandSize = true;
137 else
138 operandSize = false;
139 if ( ((prefixes & PREFIX_ADR) ^ segmentOverride) == 1)
140 addrSize = true;
141 else
142 addrSize = false;
143 this.name = getCorrectOpcodeName(name, prefixes, operandSize, addrSize);
144
145 //Fetch the mod/reg/rm byte only if it is present.
146 if( isModRMPresent(addrMode1) || isModRMPresent(addrMode2) || isModRMPresent(addrMode3) ) {
147
148 int ModRM = readByte(bytesArray, byteIndex);
149 byteIndex++;
150 mod = (ModRM >> 6) & 3;
151 regOrOpcode = (ModRM >> 3) & 7;
152 rm = ModRM & 7;
153 }
154 return decodeInstruction(bytesArray, operandSize, addrSize, factory);
155 }
156
157 protected Instruction decodeInstruction(byte[] bytesArray, boolean operandSize, boolean addrSize, X86InstructionFactory factory) {
158 Operand op1 = getOperand1(bytesArray, operandSize, addrSize);
159 Operand op2 = getOperand2(bytesArray, operandSize, addrSize);
160 Operand op3 = getOperand3(bytesArray, operandSize, addrSize);
161 int size = byteIndex - instrStartIndex;
162 return factory.newGeneralInstruction(name, op1, op2, op3, size, prefixes);
163 }
164
165 // capital letters in template are macros
166 private String getCorrectOpcodeName(String oldName, int prefixes, boolean operandSize, boolean addrSize) {
167 StringBuffer newName = new StringBuffer(oldName);
168 int index = 0;
169 for(index=0; index<oldName.length(); index++) {
170 switch (oldName.charAt(index)) {
171 case 'C': /* For jcxz/jecxz */
172 if (addrSize)
173 newName.setCharAt(index, 'e');
174 index++;
175 break;
176 case 'N':
177 if ((prefixes & PREFIX_FWAIT) == 0)
178 newName.setCharAt(index, 'n');
179 index++;
180 break;
181 case 'S':
182 /* operand size flag */
183 if (operandSize == true)
184 newName.setCharAt(index, 'l');
185 else
186 newName.setCharAt(index, 'w');
187 index++;
188 break;
189 default:
190 break;
191 }
192 }
193 return newName.toString();
194 }
195
196 //IA-32 Intel Architecture Software Developer's Manual Volume 2
197 //Refer to Chapter 2 - Instruction Format
198
199 //Get the Operand object from the address type and the operand type
200 private Operand getOperand(byte[] bytesArray, int addrMode, int operandType, boolean operandSize, boolean addrSize) {
201 Operand op = null;
202 switch(addrMode) {
203 case ADDR_E:
204 case ADDR_W: //SSE: ModR/M byte specifies either 128 bit XMM register or memory
205 case ADDR_Q: //SSE: ModR/M byte specifies either 128 bit MMX register or memory
206 X86SegmentRegister segReg = getSegmentRegisterFromPrefix(prefixes);
207
208 if (mod == 3) { //Register operand, no SIB follows
209 if (addrMode == ADDR_E) {
210 switch (operandType) {
211 case b_mode:
212 op = X86Registers.getRegister8(rm);
213 break;
214 case w_mode:
215 op = X86Registers.getRegister16(rm);
216 break;
217 case v_mode:
218 if (operandSize == true) //Operand size prefix is present
219 op = X86Registers.getRegister32(rm);
220 else
221 op = X86Registers.getRegister16(rm);
222 break;
223 case p_mode:
224 X86Register reg;
225 if (operandSize == true) //Operand size prefix is present
226 reg = X86Registers.getRegister32(rm);
227 else
228 reg = X86Registers.getRegister16(rm);
229
230 op = new X86RegisterIndirectAddress(segReg, reg, null, 0);
231 break;
232 default:
233 break;
234 }
235 } else if (addrMode == ADDR_W) {
236 op = X86XMMRegisters.getRegister(rm);
237 } else if (addrMode == ADDR_Q) {
238 op = X86MMXRegisters.getRegister(rm);
239 }
240
241 } else { //mod != 3
242 //SIB follows for (rm==4), SIB gives scale, index and base in this case
243 //disp32 is present for (mod==0 && rm==5) || (mod==2)
244 //disp8 is present for (mod==1)
245 //for (rm!=4) base is register at rm.
246 int scale = 0;
247 int index = 0;
248 int base = 0;
249 long disp = 0;
250 if(rm == 4) {
251 int sib = readByte(bytesArray, byteIndex);
252 byteIndex++;
253 scale = (sib >> 6) & 3;
254 index = (sib >> 3) & 7;
255 base = sib & 7;
256 }
257
258 switch (mod) {
259 case 0:
260 switch(rm) {
261 case 4:
262 if(base == 5) {
263 disp = readInt32(bytesArray, byteIndex);
264 byteIndex += 4;
265 if (index != 4) {
266 op = new X86RegisterIndirectAddress(segReg, null, X86Registers.getRegister32(index), disp, scale);
267 } else {
268 op = new X86RegisterIndirectAddress(segReg, null, null, disp, scale);
269 }
270 }
271 else {
272 if (index != 4) {
273 op = new X86RegisterIndirectAddress(segReg, X86Registers.getRegister32(base), X86Registers.getRegister32(index), 0, scale);
274 } else {
275 op = new X86RegisterIndirectAddress(segReg, X86Registers.getRegister32(base), null, 0, scale);
276 }
277 }
278 break;
279 case 5:
280 disp = readInt32(bytesArray, byteIndex);
281 byteIndex += 4;
282 //Create an Address object only with displacement
283 op = new X86RegisterIndirectAddress(segReg, null, null, disp);
284 break;
285 default:
286 base = rm;
287 //Create an Address object only with base
288 op = new X86RegisterIndirectAddress(segReg, X86Registers.getRegister32(base), null, 0);
289 break;
290 }
291 break;
292 case 1:
293 disp = (byte)readByte(bytesArray, byteIndex);
294 byteIndex++;
295 if (rm !=4) {
296 base = rm;
297 //Address with base and disp only
298 op = new X86RegisterIndirectAddress(segReg, X86Registers.getRegister32(base), null, disp);
299 } else {
300 if (index != 4) {
301 op = new X86RegisterIndirectAddress(segReg, X86Registers.getRegister32(base), X86Registers.getRegister32(index), disp, scale);
302 } else {
303 op = new X86RegisterIndirectAddress(segReg, X86Registers.getRegister32(base), null, disp, scale);
304 }
305 }
306 break;
307 case 2:
308 disp = readInt32(bytesArray, byteIndex);
309 byteIndex += 4;
310 if (rm !=4) {
311 base = rm;
312 //Address with base and disp
313 op = new X86RegisterIndirectAddress(segReg, X86Registers.getRegister32(base), null, disp);
314 } else if (index != 4) {
315 op = new X86RegisterIndirectAddress(segReg, X86Registers.getRegister32(base), X86Registers.getRegister32(index), disp, scale);
316 } else {
317 op = new X86RegisterIndirectAddress(segReg, X86Registers.getRegister32(base), null, disp, scale);
318 }
319 break;
320 }
321 }
322 break;
323
324 case ADDR_I:
325 switch (operandType) {
326 case b_mode:
327 op = new Immediate(new Integer(readByte(bytesArray, byteIndex)));
328 byteIndex++;
329 break;
330 case w_mode:
331 op = new Immediate(new Integer(readInt16(bytesArray, byteIndex)));
332 byteIndex += 2;
333 break;
334 case v_mode:
335 if (operandSize == true) { //Operand size prefix is present
336 op = new Immediate(new Integer(readInt32(bytesArray, byteIndex)));
337 byteIndex += 4;
338 } else {
339 op = new Immediate(new Integer(readInt16(bytesArray, byteIndex)));
340 byteIndex += 2;
341 }
342 break;
343 default:
344 break;
345 }
346 break;
347 case ADDR_REG: //registers
348 switch(operandType) {
349 case EAX:
350 case ECX:
351 case EDX:
352 case EBX:
353 case ESP:
354 case EBP:
355 case ESI:
356 case EDI:
357 if(operandSize == true) {
358 op = X86Registers.getRegister32(operandType - EAX);
359 }
360 else {
361 op = X86Registers.getRegister16(operandType - EAX);
362 }
363 break;
364 case AX:
365 case CX:
366 case DX:
367 case BX:
368 case SP:
369 case BP:
370 case SI:
371 case DI:
372 op = X86Registers.getRegister16(operandType - AX);
373 break;
374 case AL:
375 case CL:
376 case DL:
377 case BL:
378 case AH:
379 case CH:
380 case DH:
381 case BH:
382 op = X86Registers.getRegister8(operandType - AL);
383 break;
384 case ES: //ES, CS, SS, DS, FS, GS
385 case CS:
386 case SS:
387 case DS:
388 case FS:
389 case GS:
390 op = X86SegmentRegisters.getSegmentRegister(operandType - ES);
391 break;
392 }
393 break;
394 case ADDR_DIR: //segment and offset
395 long segment = 0;
396 long offset = 0;
397 switch (operandType) {
398 case p_mode:
399 if (addrSize == true) {
400 offset = readInt32(bytesArray, byteIndex);
401 byteIndex += 4;
402 segment = readInt16(bytesArray, byteIndex);
403 byteIndex += 2;
404 } else {
405 offset = readInt16(bytesArray, byteIndex);
406 byteIndex += 2;
407 segment = readInt16(bytesArray, byteIndex);
408 byteIndex += 2;
409 }
410 op = new X86DirectAddress(segment, offset); //with offset
411 break;
412 case v_mode:
413 if (addrSize == true) {
414 offset = readInt32(bytesArray, byteIndex);
415 byteIndex += 4;
416 } else {
417 offset = readInt16(bytesArray, byteIndex);
418 byteIndex += 2;
419 }
420 op = new X86DirectAddress(offset); //with offset
421 break;
422 default:
423 break;
424 }
425 break;
426 case ADDR_G:
427 switch (operandType) {
428 case b_mode:
429 op = X86Registers.getRegister8(regOrOpcode);
430 break;
431 case w_mode:
432 op = X86Registers.getRegister16(regOrOpcode);
433 break;
434 case d_mode:
435 op = X86Registers.getRegister32(regOrOpcode);
436 break;
437 case v_mode:
438 if (operandSize == true)
439 op = X86Registers.getRegister32(regOrOpcode);
440 else
441 op = X86Registers.getRegister16(regOrOpcode);
442 break;
443 default:
444 break;
445 }
446 break;
447 case ADDR_SEG:
448 op = X86SegmentRegisters.getSegmentRegister(regOrOpcode);
449 break;
450 case ADDR_OFF:
451 int off = 0;
452 if (addrSize == true) {
453 off = readInt32(bytesArray, byteIndex);
454 byteIndex += 4;
455 }
456 else {
457 off = readInt16(bytesArray, byteIndex);
458 byteIndex += 2;
459 }
460 op = new X86DirectAddress((long)off);
461 break;
462 case ADDR_J:
463 long disp = 0;
464 //The effective address is Instruction pointer + relative offset
465 switch(operandType) {
466 case b_mode:
467 disp = (byte)readByte(bytesArray, byteIndex);
468 byteIndex++;
469 break;
470 case v_mode:
471 if (operandSize == true) {
472 disp = readInt32(bytesArray, byteIndex);
473 byteIndex += 4;
474 }
475 else {
476 disp = readInt16(bytesArray, byteIndex);
477 byteIndex += 2;
478 }
479 //disp = disp + (byteIndex-instrStartIndex);
480 break;
481 }
482 op = new X86PCRelativeAddress(disp);
483 break;
484 case ADDR_ESDI:
485 op = new X86SegmentRegisterAddress(X86SegmentRegisters.ES, X86Registers.DI);
486 break;
487 case ADDR_DSSI:
488 op = new X86SegmentRegisterAddress(X86SegmentRegisters.DS, X86Registers.SI);
489 break;
490 case ADDR_R:
491 switch (operandType) {
492 case b_mode:
493 op = X86Registers.getRegister8(mod);
494 break;
495 case w_mode:
496 op = X86Registers.getRegister16(mod);
497 break;
498 case d_mode:
499 op = X86Registers.getRegister32(mod);
500 break;
501 case v_mode:
502 if (operandSize == true)
503 op = X86Registers.getRegister32(mod);
504 else
505 op = X86Registers.getRegister16(mod);
506 break;
507 default:
508 break;
509 }
510 break;
511 case ADDR_FPREG:
512 switch (operandType) {
513 case 0:
514 op = X86FloatRegisters.getRegister(0);
515 break;
516 case 1:
517 op = X86FloatRegisters.getRegister(rm);
518 break;
519 }
520 break;
521
522 //SSE: reg field of ModR/M byte selects a 128-bit XMM register
523 case ADDR_V:
524 op = X86XMMRegisters.getRegister(regOrOpcode);
525 break;
526
527 //SSE: reg field of ModR/M byte selects a 64-bit MMX register
528 case ADDR_P:
529 op = X86MMXRegisters.getRegister(regOrOpcode);
530 break;
531 }
532 return op;
533 }
534
535 private X86SegmentRegister getSegmentRegisterFromPrefix(int prefixes) {
536 X86SegmentRegister segRegister = null;
537
538 if ( (prefixes & PREFIX_CS) != 0)
539 segRegister = X86SegmentRegisters.CS;
540 if ( (prefixes & PREFIX_DS) != 0)
541 segRegister = X86SegmentRegisters.DS;
542 if ( (prefixes & PREFIX_ES) != 0)
543 segRegister = X86SegmentRegisters.ES;
544 if ( (prefixes & PREFIX_FS) != 0)
545 segRegister = X86SegmentRegisters.FS;
546 if ( (prefixes & PREFIX_SS) != 0)
547 segRegister = X86SegmentRegisters.SS;
548 if ( (prefixes & PREFIX_GS) != 0)
549 segRegister = X86SegmentRegisters.GS;
550
551 return segRegister;
552 }
553
554 }