src/org/ibex/nestedvm/JavaSourceCompiler.java

   1 package org.ibex.nestedvm;
   2
   3 import java.util.*;
   4 import java.io.*;
   5 import org.ibex.nestedvm.util.*;
   6
   7 public class JavaSourceCompiler extends Compiler {
   8     /** Stores the "case r XXX: ... run_YYYY();" blocks generated by the emitText method/ */
   9     private StringBuffer runs = new StringBuffer();
  10     /** Stores the "initData" and "cleadData" calls generated by the emitData and emitBSS methods */
  11     private StringBuffer inits = new StringBuffer();
  12     /** Stores lines to go in the class scope */
  13     private StringBuffer classLevel = new StringBuffer();
  14
  15     /** The stream to write the compiled output to */
  16     private PrintWriter out;
  17
  18     /** Prints a blank line to the output stream */
  19     private void p() { out.println(); }
  20     /** prints the given string (indented by <i>indent</i>*4 spaces) to the output stream */
  21     private void p(String s) { out.println(indents[indent] + s); }
  22     private void pblock(StringBuffer sb) { out.print(sb.toString()); }
  23
  24     /** Used by the p() method to add indentation */
  25     private int indent;
  26
  27     private static String indents[] = new String[16];
  28     static { String s=""; for(int i=0;i<indents.length;i++,s=s+"    ") indents[i] = s; }
  29
  30     public JavaSourceCompiler(Seekable binary, String className, Writer w)  throws IOException {
  31         super(binary,className);
  32         out = new PrintWriter(w);
  33     }
  34
  35     protected void _go() throws Exn, IOException {
  36         String packageName;
  37         String className;
  38         if (fullClassName.indexOf('.') != -1) {
  39             packageName = fullClassName.substring(0, fullClassName.lastIndexOf('.'));
  40             className = fullClassName.substring(fullClassName.lastIndexOf('.') + 1);
  41         } else {
  42             className = fullClassName;
  43             packageName = null;
  44         }
  45
  46         p("/* This file was generated from " + source + " by Mips2Java on " + dateTime() + " */");
  47         if (packageName != null) p("package " + packageName + ";");
  48         if(runtimeStats) p("import java.util.*;");
  49         p();
  50         p("public class " + className + " extends " + runtimeClass + " {");
  51         indent++;
  52
  53         p("/* program counter */");
  54         p("private int pc = 0;");
  55         if(debugCompiler)
  56             p("private int lastPC = 0;");
  57         p();
  58         p("/* General Purpose registers */");
  59         p("private final static int r0 = 0;");
  60         p("private int      r1,  r2,  r3,  r4,  r5,  r6,  r7,");
  61         p("            r8,  r9,  r10, r11, r12, r13, r14, r15,");
  62         p("            r16, r17, r18, r19, r20, r21, r22, r23,");
  63         p("            r24, r25, r26, r27, r28, r29, r30, r31,");
  64         p("            hi = 0, lo = 0;");
  65         p("/* FP registers */");
  66         p("private int f0,  f1,  f2,  f3,  f4,  f5,  f6,  f7,");
  67         p("            f8,  f9,  f10, f11, f12, f13, f14, f15,");
  68         p("            f16, f17, f18, f19, f20, f21, f22, f23,");
  69         p("            f24, f25, f26, f27, f28, f29, f30, f31;");
  70         p("/* FP Control Register */");
  71         p("private int fcsr = 0;");
  72         p();
  73
  74         if(onePage) p("private final int[] page = readPages[0];");
  75
  76         // Generate main body functions (run_XXXX() blocks, _data[] arrays, etc)
  77         int highestAddr = 0;
  78
  79         for(int i=0;i<elf.sheaders.length;i++) {
  80             ELF.SHeader sheader = elf.sheaders[i];
  81             String name = sheader.name;
  82             // if this section doesn't get loaded into our address space don't worry about it
  83             if(sheader.addr == 0x0) continue;
  84
  85             highestAddr = Math.max(highestAddr, sheader.addr + sheader.size);
  86
  87             if(name.equals(".text"))
  88                 emitText(sheader.addr, new DataInputStream(sheader.getInputStream()),sheader.size);
  89             else if(name.equals(".data") || name.equals(".sdata") || name.equals(".rodata") || name.equals(".ctors") || name.equals(".dtors"))
  90                 emitData(sheader.addr, new DataInputStream(sheader.getInputStream()), sheader.size,name.equals(".rodata"));
  91             else if(name.equals(".bss") || name.equals(".sbss"))
  92                 emitBSS(sheader.addr,sheader.size);
  93             else
  94                 throw new Exn("Unknown segment: " + name);
  95         }
  96         p();
  97
  98         pblock(classLevel);
  99         p();
 100
 101         // Trampoline (dispatch calls to the appropriate run_XXX() methods
 102         p("private final void trampoline() throws ExecutionException {");
 103         indent++;
 104         p("while(state == RUNNING) {");
 105         indent++;
 106         p("switch(pc>>>" + methodShift+ ") {");
 107         //p("switch(pc&" + toHex(methodMask) + ") {");
 108         indent++;
 109         pblock(runs);
 110         p("default: throw new ExecutionException(\"invalid address 0x\" + Long.toString(this.pc&0xffffffffL,16) + \": r2: \" + r2);");
 111         indent--; p("}");
 112         indent--; p("}");
 113         indent--; p("}");
 114         p();
 115
 116         // Constructor
 117         p("public " + className + "() {");
 118         indent++;
 119         p("super(" + pageSize + "," + totalPages + "," + (fastMem?"false":"true") + ");");
 120         p("entryPoint = " + toHex(elf.header.entry) + ";");
 121         if(userInfo != null) {
 122             p("userInfoBase=" + toHex(userInfo.addr) + ";");
 123             p("userInfoSize=" + userInfo.size + ";");
 124         }
 125         p("gp = " + toHex(gp.addr) + ";");
 126         if(onePage)
 127             p("brkAddr = " + toHex((highestAddr+4095)&~4095) + ";");
 128         else
 129             p("brkAddr = " + toHex((highestAddr+pageSize-1)&~(pageSize-1)) + ";");
 130         pblock(inits);
 131         p("state = INITIALIZED;");
 132         indent--;
 133         p("}");
 134         p();
 135
 136         // main() function
 137         p("public static void main(String[] args) throws Exception {");
 138         indent++;
 139         p("" + className + " me = new " + className + "();");
 140         p("int status = me.run(\"" + fullClassName + "\",args);");
 141         if(runtimeStats) p("me.printStats();");
 142         p("System.exit(status);");
 143         indent--;
 144         p("}");
 145         p();
 146
 147         // Runtime abstract methods
 148         p("protected void _execute() throws ExecutionException { trampoline(); }");
 149         p();
 150
 151         p("protected void setCPUState(CPUState state) {");
 152         indent++;
 153         for(int i=1;i<32;i++) p("r" + i + "=state.r[" + i + "];");
 154         for(int i=0;i<32;i++) p("f" + i + "=state.f[" + i + "];");
 155         p("hi=state.hi; lo=state.lo; fcsr=state.fcsr;");
 156         p("pc=state.pc;");
 157         indent--;
 158         p("}");
 159         p("protected CPUState getCPUState() {");
 160         indent++;
 161         p("CPUState state = new CPUState();");
 162         for(int i=1;i<32;i++) p("state.r[" + i + "]=r" + i+ ";");
 163         for(int i=0;i<32;i++) p("state.f[" + i + "]=f" + i +";");
 164         p("state.hi=hi; state.lo=lo; state.fcsr=fcsr;");
 165         p("state.pc=pc;");
 166         p("return state;");
 167         indent--;
 168         p("}");
 169         p();
 170
 171         if(supportCall) {
 172             p("private static final " + hashClass + " symbols = new " + hashClass + "();");
 173             p("static {");
 174             indent++;
 175             ELF.Symbol[] symbols = elf.getSymtab().symbols;
 176             for(int i=0;i<symbols.length;i++) {
 177                 ELF.Symbol s = symbols[i];
 178                 if(s.type == ELF.Symbol.STT_FUNC && s.binding == ELF.Symbol.STB_GLOBAL && (s.name.equals("_call_helper") || !s.name.startsWith("_")))
 179                     p("symbols.put(\"" + s.name + "\",new Integer(" + toHex(s.addr) + "));");
 180             }
 181             indent--;
 182             p("}");
 183             p("public int lookupSymbol(String symbol) { Integer i = (Integer) symbols.get(symbol); return i==null ? -1 : i.intValue(); }");
 184             p();
 185         }
 186
 187         // Runtime stats
 188         if(runtimeStats) {
 189             p("private HashMap counters = new HashMap();");
 190             p("private void inc(String k) { Long i = (Long)counters.get(k); counters.put(k,new Long(i==null ? 1 : i.longValue() + 1)); }");
 191             p("private void printStats() {");
 192             p(" Iterator i = new TreeSet(counters.keySet()).iterator();");
 193             p(" while(i.hasNext()) { Object o = i.next(); System.err.println(\"\" + o + \": \" + counters.get(o)); }");
 194             p("}");
 195             p();
 196         }
 197
 198         indent--;
 199         p("}");
 200     }
 201
 202     private int startOfMethod = 0;
 203     private int endOfMethod = 0;
 204
 205     private void startMethod(int addr) {
 206         addr &= ~(maxBytesPerMethod-1);
 207         startOfMethod = addr;
 208         endOfMethod = addr + maxBytesPerMethod;
 209         String methodName = "run_" + Long.toString(addr & 0xffffffffL, 16);
 210         runs.append(indents[4] + "case " + toHex(addr>>>methodShift) + ": " + methodName + "(); break; \n");
 211         //runs.append(indents[4] + "case " + toHex(addr&methodMask) + ": " + methodName + "(); break; \n");
 212
 213         p("private final void " + methodName + "() throws ExecutionException { /"+"* " + toHex(addr) + " - " + toHex(endOfMethod) + " *" + "/");
 214         indent++;
 215         p("int addr, tmp;");
 216         p("for(;;) {");
 217         indent++;
 218         p("switch(pc) {");
 219         indent++;
 220     }
 221
 222     private void endMethod() { endMethod(endOfMethod); }
 223     private void endMethod(int lastAddr) {
 224         if(startOfMethod == 0) return;
 225         // FEATURE: We should be able to use if(!unreachable) here (i think)
 226         // This isn't strictly necessary; its just here to work around unreachable code errors
 227         p("case " + toHex(lastAddr) + ":");
 228         indent++;
 229         p("pc=" + constant(lastAddr) + ";");
 230         leaveMethod();
 231         indent--;
 232         if(debugCompiler)
 233             p("default: throw new ExecutionException(\"invalid address 0x\" + Long.toString(pc&0xffffffffL,16)  + \" (got here from 0x\" + Long.toString(lastPC&0xffffffffL,16)+\")\");");
 234         else
 235             p("default: throw new ExecutionException(\"invalid address 0x\" + Long.toString(pc&0xffffffffL,16));");
 236         indent--;
 237         p("}"); // end switch
 238         p("/* NOT REACHED */");
 239         indent--;
 240         p("}"); // end for
 241         indent--;
 242         p("}"); // end method
 243         endOfMethod = startOfMethod = 0;
 244     }
 245
 246     private HashMap relativeAddrs = new HashMap();
 247     private String constant(int target) {
 248         if(target >= 4096 && lessConstants) {
 249             int n = target & ~1023;
 250             String var = "N_" + toHex8(n);
 251             if(relativeAddrs.get(new Integer(n)) == null) {
 252                 relativeAddrs.put(new Integer(n),Boolean.TRUE);
 253                 classLevel.append(indents[1] + "private static int " + var + " = " + toHex(n) + ";\n");
 254             }
 255             return "(" + var + " + " + toHex(target - n) + ")";
 256         } else {
 257             return toHex(target);
 258         }
 259     }
 260
 261     private void branch(int pc, int target) {
 262         if(debugCompiler) p("lastPC = " + toHex(pc) + ";");
 263         p("pc=" + constant(target) + ";");
 264         if(target == 0)
 265             p("throw new ExecutionException(\"Branch to addr 0x0\");");
 266         else if((pc&methodMask) == (target&methodMask))
 267             p("continue;");
 268         else if(assumeTailCalls)
 269             p("run_" +  Long.toString((target&methodMask)&0xffffffffL, 16) + "(); return;");
 270         else
 271             leaveMethod();
 272     }
 273
 274     private void leaveMethod() {
 275         p("return;");
 276     }
 277
 278     private boolean textDone;
 279     private void emitText(int addr, DataInputStream dis, int size) throws Exn,IOException {
 280         if(textDone) throw new Exn("Multiple text segments");
 281         textDone = true;
 282
 283         if((addr&3)!=0 || (size&3)!=0) throw new Exn("Section on weird boundaries");
 284         int count = size/4;
 285         int nextInsn = dis.readInt();
 286         if(nextInsn == -1) throw new Error("Actually read -1 at " + toHex(addr));
 287         int insn;
 288
 289         for(int i=0;i<count;i++,addr+=4) {
 290             insn = nextInsn;
 291             nextInsn = (i == count-1) ? -1 : dis.readInt();
 292             if(addr >= endOfMethod) { endMethod(); startMethod(addr); }
 293             if(jumpableAddresses==null || addr == startOfMethod || jumpableAddresses.contains(new Integer(addr))) {
 294                 p("case " + toHex(addr) + ":");
 295                 unreachable = false;
 296             } else if(unreachable) {
 297                 continue;
 298             } else if(debugCompiler) {
 299                 p("/" + "* pc = " + toHex(addr) + "*" + "/");
 300             }
 301             indent++;
 302             emitInstruction(addr,insn,nextInsn);
 303             indent--;
 304         }
 305         endMethod(addr);
 306         p();
 307         dis.close();
 308     }
 309
 310     private int initDataCount = 0;
 311     private void emitData(int addr, DataInputStream dis, int size, boolean readOnly) throws Exn,IOException {
 312         if((addr&3)!=0 || (size&3)!=0) throw new Exn("Data section on weird boundaries");
 313         int last = addr + size;
 314         while(addr < last) {
 315             int segSize = Math.min(size,28000); // must be a multiple of 56
 316             StringBuffer sb = new StringBuffer();
 317             for(int i=0;i<segSize;i+=7) {
 318                 long l = 0;
 319                 for(int j=0;j<7;j++) {
 320                     l <<= 8;
 321                     byte b = (i+j < size) ? dis.readByte() : 1;
 322                     l |= (b & 0xffL);
 323                 }
 324                 for(int j=0;j<8;j++) {
 325                     char c = (char) ((l>>>(7*(7-j)))&0x7f);
 326                     if(c=='\n') sb.append("\\n");
 327                     else if(c=='\r') sb.append("\\r");
 328                     else if(c=='\\') sb.append("\\\\");
 329                     else if(c=='"') sb.append("\\\"");
 330                     else if(c >= 32 && c <= 126) sb.append(c);
 331                     else sb.append("\\" +  toOctal3(c));
 332                 }
 333             }
 334             String varname =  "_data" + (++initDataCount);
 335             p("private static final int[] " + varname + " = decodeData(\"" + sb.toString() + "\"," + toHex(segSize/4) + ");");
 336             inits.append(indents[2] + "initPages(" + varname +"," + toHex(addr) + "," + (readOnly?"true":"false") + ");\n");
 337             addr += segSize;
 338             size -= segSize;
 339         }
 340         dis.close();
 341     }
 342
 343     private void emitBSS(int addr, int size) throws Exn {
 344         if((addr&3)!=0) throw new Exn("BSS section on weird boundaries");
 345         size = (size+3)&~3;
 346         int count = size/4;
 347         inits.append(indents[2] + "clearPages(" + toHex(addr) + "," + toHex(count) + ");\n");
 348     }
 349
 350     // True if the current code path is unreachable (any instruction with a case statement is reachable)
 351     private boolean unreachable = false;
 352
 353     private void emitInstruction(int pc, int insn, int nextInsn) throws IOException,Exn {
 354         if(insn == -1) throw new Error("insn is -1");
 355
 356         int op = (insn >>> 26) & 0xff;                 // bits 26-31
 357         int rs = (insn >>> 21) & 0x1f;                 // bits 21-25
 358         int rt = (insn >>> 16) & 0x1f;                 // bits 16-20
 359         int ft = (insn >>> 16) & 0x1f;
 360         int rd = (insn >>> 11) & 0x1f;                 // bits 11-15
 361         int fs = (insn >>> 11) & 0x1f;
 362         int shamt = (insn >>> 6) & 0x1f;               // bits 6-10
 363         int fd = (insn >>> 6) & 0x1f;
 364         int subcode = insn & 0x3f;                     // bits 0-5
 365
 366         int jumpTarget = (insn & 0x03ffffff);          // bits 0-25
 367         int unsignedImmediate = insn & 0xffff;
 368         int signedImmediate = (insn << 16) >> 16;
 369         int branchTarget = signedImmediate;
 370
 371         int tmp; // temporaries
 372
 373         //if(pc%64==0) p("System.err.println(\"Executing: " + toHex(pc) + "\");");
 374         //p("/" + "*" + (pc == -1 ? "Delay Slot"  : toHex(pc)) + " *" + "/ ");
 375         if(pc==-1) p("/" + "* Next insn is delay slot *" + "/ ");
 376
 377         if(runtimeStats && op != 0) p("inc(\"opcode: " + op + "\");");
 378         switch(op) {
 379             case 0: {
 380                 if(runtimeStats && insn != 0) p("inc(\"opcode: 0/" + subcode + "\");");
 381                 switch(subcode) {
 382                     case 0: // SLL
 383                         if(insn != 0)
 384                             p( "r"+rd+" = r"+rt+" << "+shamt+";");
 385                         break;
 386                     case 2: // SRL
 387                         p( "r"+rd+" = r"+rt+" >>> "+shamt+";");
 388                         break;
 389                     case 3: // SRA
 390                         p( "r"+rd+" = r"+rt+" >> "+shamt+";");
 391                         break;
 392                     case 4: // SLLV
 393                         p( "r"+rd+" = r"+rt+" << (r"+rs+"&0x1f);");
 394                         break;
 395                     case 6: // SRLV
 396                         p( "r"+rd+" = r"+rt+" >>> (r"+rs+"&0x1f);");
 397                         break;
 398                     case 7: // SRAV
 399                         p( "r"+rd+" = r"+rt+" >> (r"+rs+"&0x1f);");
 400                         break;
 401                     case 8: // JR
 402                         if(pc == -1) throw new Error("pc modifying insn in delay slot");
 403                         emitInstruction(-1,nextInsn,-1);
 404                         if(debugCompiler) p("lastPC = " + toHex(pc) + ";");
 405                         p("pc=r" + rs + ";");
 406                         leaveMethod();
 407                         unreachable = true;
 408                         break;
 409                     case 9: // JALR
 410                         if(pc == -1) throw new Error("pc modifying insn in delay slot");
 411                         emitInstruction(-1,nextInsn,-1);
 412                         if(debugCompiler) p("lastPC = " + toHex(pc) + ";");
 413                         p("pc=r" + rs + ";");
 414                         p("r" + RA + "=" + constant(pc+8 /*skip this insn and delay slot*/) + ";");
 415                         leaveMethod();
 416                         unreachable = true;
 417                         break;
 418                     case 12: // SYSCALL
 419                         p("pc = " + toHex(pc) + ";");
 420                         p( "r"+V0+" = syscall(r"+V0+",r"+A0+",r"+A1+",r"+A2+",r"+A3+");");
 421                         p("if (state != RUNNING) {");
 422                             indent++;
 423                             p("pc = " + toHex(pc+4) + ";");
 424                             leaveMethod();
 425                             indent--;
 426                         p("}");
 427                         break;
 428                     case 13: // BREAK
 429                         p( "throw new ExecutionException(\"Break\");");
 430                         break;
 431                     case 16: // MFHI
 432                         p( "r"+rd+" = hi;");
 433                         break;
 434                     case 17: // MTHI
 435                         p( "hi = r"+rs+";");
 436                         break;
 437                     case 18: // MFLO
 438                         p( "r"+rd+" = lo;");
 439                         break;
 440                     case 19: // MTLO
 441                         p( "lo = r"+rs+";");
 442                         break;
 443                     case 24: // MULT
 444                         p( "{ long hilo = (long)(r"+rs+") * ((long)r"+rt+"); " +
 445                              "hi = (int) (hilo >>> 32); " +
 446                              "lo = (int) hilo; }");
 447                         break;
 448                     case 25: // MULTU
 449                         p( "{ long hilo = (r"+rs+" & 0xffffffffL) * (r"+rt+" & 0xffffffffL); " +
 450                              "hi = (int) (hilo >>> 32); " +
 451                              "lo = (int) hilo; } ");
 452                         break;
 453                     case 26: // DIV
 454                         p( "hi = r"+rs+"%r"+rt+"; lo = r"+rs+"/r"+rt+";");
 455                         break;
 456                     case 27: // DIVU
 457                         p("if(r"+rt+"!=0) {");
 458                         p( "hi = (int)((r"+rs+" & 0xffffffffL) % (r"+rt+" & 0xffffffffL)); " +
 459                              "lo = (int)((r"+rs+" & 0xffffffffL) / (r"+rt+" & 0xffffffffL));");
 460                         p("}");
 461                         break;
 462                     case 32: // ADD
 463                          throw new Exn("ADD (add with oveflow trap) not suported");
 464                         /*This must trap on overflow
 465                         p( "r"+rd+" = r"+rs+" + r"+rt+";");
 466                         break;*/
 467                     case 33: // ADDU
 468                         p( "r"+rd+" = r"+rs+" + r"+rt+";");
 469                         break;
 470                     case 34: // SUB
 471                          throw new Exn("SUB (add with oveflow trap) not suported");
 472                         /*This must trap on overflow
 473                         p( "r"+rd+" = r"+rs+" - r"+rt+";");
 474                         break;*/
 475                     case 35: // SUBU
 476                         p( "r"+rd+" = r"+rs+" - r"+rt+";");
 477                         break;
 478                     case 36: // AND
 479                         p( "r"+rd+" = r"+rs+" & r"+rt+";");
 480                         break;
 481                     case 37: // OR
 482                         p( "r"+rd+" = r"+rs+" | r"+rt+";");
 483                         break;
 484                     case 38: // XOR
 485                         p( "r"+rd+" = r"+rs+" ^ r"+rt+";");
 486                         break;
 487                     case 39: // NOR
 488                         p( "r"+rd+" = ~(r"+rs+" | r"+rt+");");
 489                         break;
 490                     case 42: // SLT
 491                         p( "r"+rd+" = r"+rs+" < r"+rt+" ? 1 : 0;");
 492                         break;
 493                     case 43: // SLTU
 494                         p( "r"+rd+" = ((r"+rs+" & 0xffffffffL) < (r"+rt+" & 0xffffffffL)) ? 1 : 0;");
 495                         break;
 496                     default:
 497                         throw new RuntimeException("Illegal instruction 0/" + subcode);
 498                 }
 499                 break;
 500             }
 501             case 1: {
 502                 switch(rt) {
 503                     case 0: // BLTZ
 504                         if(pc == -1) throw new Error("pc modifying insn in delay slot");
 505                         p("if(r" + rs + " < 0) {");
 506                             indent++;
 507                             emitInstruction(-1,nextInsn,-1);
 508                             branch(pc,pc+branchTarget*4+4);
 509                             indent--;
 510                         p("}");
 511                         break;
 512                     case 1: // BGEZ
 513                         if(pc == -1) throw new Error("pc modifying insn in delay slot");
 514                         p("if(r" + rs + " >= 0) {");
 515                             indent++;
 516                             emitInstruction(-1,nextInsn,-1);
 517                             branch(pc,pc+branchTarget*4+4);
 518                             indent--;
 519                         p("}");
 520                         break;
 521                     case 16: // BLTZAL
 522                         if(pc == -1) throw new Error("pc modifying insn in delay slot");
 523                         p("if(r" + rs + " < 0) {");
 524                             indent++;
 525                             emitInstruction(-1,nextInsn,-1);
 526                             p("r" + RA + "=" + constant(pc+8 /*skip this insn and delay slot*/) + ";");
 527                             branch(pc,pc+branchTarget*4+4);
 528                             indent--;
 529                         p("}");
 530                         break;
 531                     case 17: // BGEZAL
 532                         if(pc == -1) throw new Error("pc modifying insn in delay slot");
 533                         p("if(r" + rs + " >= 0) {");
 534                             indent++;
 535                             emitInstruction(-1,nextInsn,-1);
 536                             p("r" + RA + "=" + constant(pc+8 /*skip this insn and delay slot*/) + ";");
 537                             branch(pc,pc+branchTarget*4+4);
 538                             indent--;
 539                         p("}");
 540                         break;
 541                     default:
 542                         throw new RuntimeException("Illegal Instruction 1/" + rt);
 543                 }
 544                 break;
 545             }
 546             case 2: { // J
 547                 if(pc == -1) throw new Error("pc modifying insn in delay slot");
 548                 emitInstruction(-1,nextInsn,-1);
 549                 branch(pc,(pc&0xf0000000)|(jumpTarget << 2));
 550                 unreachable = true;
 551                 break;
 552             }
 553             case 3: { // JAL
 554                 if(pc == -1) throw new Error("pc modifying insn in delay slot");
 555                 int target = (pc&0xf0000000)|(jumpTarget << 2);
 556                 emitInstruction(-1,nextInsn,-1);
 557                 if(optimizedMemcpy && (target == memcpy || target == memset)) {
 558                     if(target == memcpy)
 559                         p("memcpy(r4,r5,r6);");
 560                     else if(target == memset)
 561                         p("memset(r4,r5,r6);");
 562                     p("r2 = r4;");
 563                     branch(pc,pc+8);
 564                 } else {
 565                     p("r" + RA + "=" + constant(pc+8 /*skip this insn and delay slot*/) + ";");
 566                     branch(pc, target);
 567                 }
 568                 unreachable = true;
 569                 break;
 570             }
 571             case 4: // BEQ
 572                 if(pc == -1) throw new Error("pc modifying insn in delay slot");
 573                 p("if(r" + rs + " == r" + rt + ") {");
 574                     indent++;
 575                     emitInstruction(-1,nextInsn,-1);
 576                     branch(pc,pc+branchTarget*4+4);
 577                     indent--;
 578                 p("}");
 579                 break;
 580             case 5: // BNE
 581                 if(pc == -1) throw new Error("pc modifying insn in delay slot");
 582                 p("if(r" + rs + " != r" + rt + ") {");
 583                     indent++;
 584                     emitInstruction(-1,nextInsn,-1);
 585                     branch(pc,pc+branchTarget*4+4);
 586                     indent--;
 587                 p("}");
 588                 break;
 589             case 6: //BLEZ
 590                 if(pc == -1) throw new Error("pc modifying insn in delay slot");
 591                 p("if(r" + rs + " <= 0) {");
 592                     indent++;
 593                     emitInstruction(-1,nextInsn,-1);
 594                     branch(pc,pc+branchTarget*4+4);
 595                     indent--;
 596                 p("}");
 597                 break;
 598             case 7: //BGTZ
 599                 if(pc == -1) throw new Error("pc modifying insn in delay slot");
 600                 p("if(r" + rs + " > 0) {");
 601                     indent++;
 602                     emitInstruction(-1,nextInsn,-1);
 603                     branch(pc,pc+branchTarget*4+4);
 604                     indent--;
 605                 p("}");
 606                 break;
 607             case 8: // ADDI
 608                 p( "r"+rt+" = r"+rs+" + "+signedImmediate +";");
 609                 break;
 610             case 9: // ADDIU
 611                 p( "r"+rt+" = r"+rs+" + "+signedImmediate+";");
 612                 break;
 613             case 10: // SLTI
 614                 p( "r"+rt+" = r"+rs+" < "+signedImmediate+" ? 1 : 0;");
 615                 break;
 616             case 11: // SLTIU
 617                 p( "r"+rt+" = (r"+rs+"&0xffffffffL) < ("+unsignedImmediate+"&0xffffffffL) ? 1 : 0;");
 618                 break;
 619             case 12: // ANDI
 620                 p( "r"+rt+" = r"+rs+" & "+unsignedImmediate+";");
 621                 break;
 622             case 13: // ORI
 623                 p( "r"+rt+" = r"+rs+" | "+unsignedImmediate+";");
 624                 break;
 625             case 14: // XORI
 626                 p( "r"+rt+" = r"+rs+" ^ "+unsignedImmediate+";");
 627                 break;
 628             case 15: // LUI
 629                 p( "r"+rt+" = "+unsignedImmediate+" << 16;");
 630                 break;
 631             case 16:
 632                 throw new Exn("TLB/Exception support not implemented");
 633             case 17: { // FPU
 634                 switch(rs) {
 635                     case 0: // MFC.1
 636                         p( "r"+rt+" = f"+rd+";");
 637                         break;
 638                     case 2: // CFC.1
 639                         if(fs != 31) throw new Exn("FCR " + fs + " unavailable");
 640                         p( "r"+rt+" = fcsr;");
 641                         break;
 642                     case 4: // MTC.1
 643                         p( "f"+rd+" = r"+rt+";");
 644                         break;
 645                     case 6: // CTC.1
 646                         if(fs != 31) throw new Exn("FCR " + fs + " unavailable");
 647                         p( "fcsr = r"+rt+";");
 648                         break;
 649                     case 8: {// BC1F, BC1T
 650                         tmp = (insn>>>16)&1;
 651                         p("if(((fcsr&0x800000)!=0) == (" + tmp + "!=0)) {");
 652                             indent++;
 653                             emitInstruction(-1,nextInsn,-1);
 654                             branch(pc,pc+branchTarget*4+4);
 655                             indent--;
 656                         p("}");
 657                         break;
 658                     }
 659                     case 16: {  // Single
 660                         switch(subcode) {
 661                             case 0: // ADD.S
 662                                 p(setFloat(fd,getFloat(fs)+"+"+getFloat(ft)));
 663                                 break;
 664                             case 1: // SUB.S
 665                                 p(setFloat(fd,getFloat(fs)+"-"+getFloat(ft)));
 666                                 break;
 667                             case 2: // MUL.S
 668                                 p(setFloat(fd,getFloat(fs)+"*"+getFloat(ft)));
 669                                 break;
 670                             case 3: // DIV.S
 671                                 p(setFloat(fd,getFloat(fs)+"/"+getFloat(ft)));
 672                                 break;
 673                             case 5: // ABS.S
 674                                 p(setFloat(fd,"Math.abs("+getFloat(fs)+")"));
 675                                 break;
 676                             case 6: // MOV.S
 677                                 p("f"+fd+" = f"+fs+"; // MOV.S");
 678                                 break;
 679                             case 7: // NEG.S
 680                                 p(setFloat(fd,"-"+getFloat(fs)));
 681                                 break;
 682                             case 33: // CVT.D.S
 683                                 p(setDouble(fd,"(float)"+getFloat(fs)));
 684                                 break;
 685                             case 36: // CVT.W.D
 686                                 p("switch(fcsr & 3) {");
 687                                     indent++;
 688                                     p("case 0: f"+fd+" = (int)Math.floor("+getFloat(fs)+"+0.5); break; // Round to nearest");
 689                                     p("case 1: f"+fd+" = (int)"+getFloat(fs)+"; break; // Round towards zero");
 690                                     p("case 2: f"+fd+" = (int)Math.ceil("+getFloat(fs)+"); break; // Round towards plus infinity");
 691                                     p("case 3: f"+fd+" = (int)Math.floor("+getFloat(fs)+"); break; // Round towards minus infinity");
 692                                     indent--;
 693                                 p("}");
 694                                 break;
 695                             case 50: // C.EQ.S
 696                                 p("fcsr = (fcsr&~0x800000) | (("+getFloat(fs)+"=="+getFloat(ft)+") ? 0x800000 : 0x000000);");
 697                                 break;
 698                             case 60: // C.LT.S
 699                                 p("fcsr = (fcsr&~0x800000) | (("+getFloat(fs)+"<"+getFloat(ft)+") ? 0x800000 : 0x000000);");
 700                                 break;
 701                             case 62: // C.LE.S
 702                                 p("fcsr = (fcsr&~0x800000) | (("+getFloat(fs)+"<="+getFloat(ft)+") ? 0x800000 : 0x000000);");
 703                                 break;
 704                             default: throw new Exn("Invalid Instruction 17/" + rs + "/" + subcode);
 705                         }
 706                         break;
 707                     }
 708                     case 17: { // Double
 709                         switch(subcode) {
 710                             case 0: // ADD.D
 711                                 p(setDouble(fd,getDouble(fs)+"+"+getDouble(ft)));
 712                                 break;
 713                             case 1: // SUB.D
 714                                 p(setDouble(fd,getDouble(fs)+"-"+getDouble(ft)));
 715                                 break;
 716                             case 2: // MUL.D
 717                                 p(setDouble(fd,getDouble(fs)+"*"+getDouble(ft)));
 718                                 break;
 719                             case 3: // DIV.D
 720                                 p(setDouble(fd,getDouble(fs)+"/"+getDouble(ft)));
 721                                 break;
 722                             case 5: // ABS.D
 723                                 p(setDouble(fd,"Math.abs("+getDouble(fs)+")"));
 724                                 break;
 725                             case 6: // MOV.D
 726                                 p("f"+fd+" = f"+fs+";");
 727                                 p("f"+(fd+1)+" = f"+(fs+1)+";");
 728                                 break;
 729                             case 7: // NEG.D
 730                                 p(setDouble(fd,"-"+getDouble(fs)));
 731                                 break;
 732                             case 32: // CVT.S.D
 733                                 p(setFloat(fd,"(float)"+getDouble(fs)));
 734                                 break;
 735                             case 36: // CVT.W.D
 736                                 p("switch(fcsr & 3) {");
 737                                     indent++;
 738                                     p("case 0: f"+fd+" = (int)Math.floor("+getDouble(fs)+"+0.5); break; // Round to nearest");
 739                                     p("case 1: f"+fd+" = (int)"+getDouble(fs)+"; break; // Round towards zero");
 740                                     p("case 2: f"+fd+" = (int)Math.ceil("+getDouble(fs)+"); break; // Round towards plus infinity");
 741                                     p("case 3: f"+fd+" = (int)Math.floor("+getDouble(fs)+"); break; // Round towards minus infinity");
 742                                     indent--;
 743                                 p("}");
 744                                 break;
 745                             case 50: // C.EQ.D
 746                                 p("fcsr = (fcsr&~0x800000) | (("+getDouble(fs)+"=="+getDouble(ft)+") ? 0x800000 : 0x000000);");
 747                                 break;
 748                             case 60: // C.LT.D
 749                                 p("fcsr = (fcsr&~0x800000) | (("+getDouble(fs)+"<"+getDouble(ft)+") ? 0x800000 : 0x000000);");
 750                                 break;
 751                             case 62: // C.LE.D
 752                                 p("fcsr = (fcsr&~0x800000) | (("+getDouble(fs)+"<="+getDouble(ft)+") ? 0x800000 : 0x000000);");
 753                                 break;
 754                             default: throw new Exn("Invalid Instruction 17/" + rs + "/" + subcode);
 755                         }
 756                         break;
 757                     }
 758                     case 20: { // Integer
 759                         switch(subcode) {
 760                             case 32: // CVT.S.W
 761                                 p(" // CVS.S.W");
 762                                 p(setFloat(fd,"((float)f"+fs+")"));
 763                                 break;
 764                             case 33: // CVT.D.W
 765                                 p(setDouble(fd,"((double)f"+fs+")"));
 766                                 break;
 767                             default: throw new Exn("Invalid Instruction 17/" + rs + "/" + subcode);
 768                         }
 769                         break;
 770                     }
 771                     default:
 772                         throw new Exn("Invalid Instruction 17/" + rs);
 773                 }
 774                 break;
 775             }
 776             case 18: case 19:
 777                 throw new Exn("coprocessor 2 and 3 instructions not available");
 778             case 32: { // LB
 779                 if(runtimeStats) p("inc(\"LB\");");
 780                 p("addr=r" + rs +"+"+signedImmediate + ";");
 781                 memRead("addr","tmp");
 782                 p("tmp = (tmp>>>(((~addr)&3)<<3)) & 0xff;");
 783                 p("if((tmp&0x80)!=0) tmp |= 0xffffff00; /* sign extend */");
 784                 p("r"+rt+" = tmp;");
 785                 break;
 786             }
 787             case 33: { // LH
 788                 if(runtimeStats) p("inc(\"LH\");");
 789                 p("addr=r" + rs +"+"+signedImmediate + ";");
 790                 memRead("addr","tmp");
 791                 p("tmp = (tmp>>>(((~addr)&2)<<3)) & 0xffff;");
 792                 p("if((tmp&0x8000)!=0) tmp |= 0xffff0000; /* sign extend */");
 793                 p("r"+rt+" = tmp;");
 794                 break;
 795             }
 796             case 34: { // LWL;
 797                 p("addr=r" + rs +"+"+signedImmediate + ";");
 798                 memRead("addr","tmp");
 799                 p("r" + rt + " = (r"+rt+"&(0x00ffffff>>>(((~addr)&3)<<3)))|(tmp<<((addr&3)<<3));");
 800                 break;
 801                 /*p("addr=r" + rs +"+"+signedImmediate + ";");
 802                 memRead("addr&~3","tmp");
 803                 p("switch(addr&3) {");
 804                 indent++;
 805                 p("case 0: r"+rt+" = (r"+rt+"&0x00000000)|(tmp<< 0); break;");
 806                 p("case 1: r"+rt+" = (r"+rt+"&0x000000ff)|(tmp<< 8); break;");
 807                 p("case 2: r"+rt+" = (r"+rt+"&0x0000ffff)|(tmp<<16); break;");
 808                 p("case 3: r"+rt+" = (r"+rt+"&0x00ffffff)|(tmp<<24); break;");
 809                 indent--;
 810                 p("}");
 811                 break;*/
 812             }
 813             case 35: // LW
 814                 if(runtimeStats) p("inc(\"LW\");");
 815                 memRead("r" + rs +"+"+signedImmediate,"r"+rt);
 816                 break;
 817             case 36: { // LBU
 818                 p("addr=r" + rs +"+"+signedImmediate + ";");
 819                 memRead("addr","tmp");
 820                 p("tmp = (tmp>>>(((~addr)&3)<<3)) & 0xff;");
 821                 p("r"+rt+" = tmp;");
 822                 break;
 823             }
 824             case 37: { // LHU
 825                 p("addr=r" + rs +"+"+signedImmediate + ";");
 826                 memRead("addr","tmp");
 827                 p("tmp = (tmp>>>(((~addr)&2)<<3)) & 0xffff;");
 828                 p("r"+rt+" = tmp;");
 829                 break;
 830             }
 831             case 38: { // LWR
 832                 p("addr=r" + rs +"+"+signedImmediate + ";");
 833                 memRead("addr","tmp");
 834                 p("r" + rt + " = (r"+rt+"&(0xffffff00<<((addr&3)<<3)))|(tmp>>>(((~addr)&3)<<3));");
 835                 break;
 836
 837                 /*p("addr=r" + rs +"+"+signedImmediate + ";");
 838                 memRead("addr&~3","tmp");
 839                 p("switch(addr&3) {");
 840                 indent++;
 841                 p("case 0: r"+rt+" = (r"+rt+"&0xffffff00)|(tmp>>>24); break;");
 842                 p("case 1: r"+rt+" = (r"+rt+"&0xffff0000)|(tmp>>>16); break;");
 843                 p("case 2: r"+rt+" = (r"+rt+"&0xff000000)|(tmp>>> 8); break;");
 844                 p("case 3: r"+rt+" = (r"+rt+"&0x00000000)|(tmp>>> 0); break;");
 845                 indent--;
 846                 p("}");
 847                 break;*/
 848
 849             }
 850             case 40: { // SB
 851                 if(runtimeStats) p("inc(\"SB\");");
 852                 p("addr=r" + rs +"+"+signedImmediate + ";");
 853                 memRead("addr","tmp");
 854                 p("tmp = (tmp&~(0xff000000>>>((addr&3)<<3)))|((r"+rt+"&0xff)<<(((~addr)&3)<<3));");
 855                 memWrite("addr","tmp");
 856                 break;
 857             }
 858             case 41: { // SH
 859                 if(runtimeStats) p("inc(\"SH\");");
 860                 p("addr=r" + rs +"+"+signedImmediate + ";");
 861                 memRead("addr","tmp");
 862                 p("tmp = (tmp&(0xffff<<((addr&2)<<3)))|((r" + rt + "&0xffff)<<(((~addr)&2)<<3));");
 863                 memWrite("addr","tmp");
 864                 break;
 865             }
 866             case 42: { // SWL
 867                 p(" // SWL");
 868                 p("addr=r" + rs +"+"+signedImmediate + ";");
 869                 memRead("addr","tmp");
 870                 p("tmp = (tmp&(0xffffff00<<(((~addr)&3)<<3)))|(r"+rt+">>>((addr&3)<<3));");
 871                 memWrite("addr","tmp");
 872                 break;
 873             }
 874             case 43: // SW
 875                 if(runtimeStats) p("inc(\"SW\");");
 876                 memWrite("r"+rs+"+"+signedImmediate,"r" + rt);
 877                 break;
 878             case 46: { // SWR
 879                 p(" // SWR");
 880                 p("addr=r" + rs +"+"+signedImmediate + ";");
 881                 memRead("addr","tmp");
 882                 p("tmp = (tmp&(0x00ffffff>>>((addr&3)<<3)))|(r"+rt+"<<(((~addr)&3)<<3));");
 883                 memWrite("addr","tmp");
 884                 break;
 885             }
 886             // FEATURE: Need to be atomic if threads
 887             case 48: // LWC0/LL
 888                 memRead("r"+rs+"+"+signedImmediate,"r"+rt);
 889                 break;
 890             case 49: // LWC1
 891                 memRead("r"+rs+"+"+signedImmediate,"f"+rt);
 892                 break;
 893             // FEATURE: Needs to be atomic if threads
 894             case 56: // SWC1/SC
 895                 memWrite("r"+rs+"+"+signedImmediate,"r"+rt);
 896                 p("r" + rt + "=1;");
 897                 break;
 898             case 57: // SWC1
 899                 memWrite("r"+rs+"+"+signedImmediate,"f"+rt);
 900                 break;
 901             default:
 902                 throw new Exn("Invalid Instruction: " + op + " at " + toHex(pc));
 903         }
 904     }
 905
 906     // Helper functions for emitText
 907     // NOTE: memWrite and memRead MUST discard the last two bits of addr
 908     private void memWrite(String addr, String target) {
 909         if(nullPointerCheck) p("nullPointerCheck(" + addr + ");");
 910         if(onePage)
 911             p("page[(" + addr + ")>>>2] = " + target + ";");
 912         else if(fastMem)
 913             p("writePages[("+addr+")>>>"+pageShift+"][(("+addr+")>>>2)&"+toHex((pageSize>>2)-1)+"] = " + target + ";");
 914         else
 915             p("unsafeMemWrite(" + addr + "," + target + ");");
 916     }
 917     private void memRead(String addr, String target) {
 918         if(nullPointerCheck) p("nullPointerCheck(" + addr + ");");
 919         if(onePage)
 920             p(target + "= page[(" + addr + ")>>>2];");
 921         else if(fastMem)
 922             p(target  + " = readPages[("+addr+")>>>"+pageShift+"][(("+addr+")>>>2)&"+toHex((pageSize>>2)-1)+"];");
 923         else
 924             p(target + " = unsafeMemRead(" + addr + ");");
 925     }
 926     private static String getFloat(int r) { return "(Float.intBitsToFloat(f"+r+"))"; }
 927     private static String getDouble(int r) {
 928         return "(Double.longBitsToDouble(((f"+(r+1)+"&0xffffffffL) << 32) | (f"+r+"&0xffffffffL)))";
 929     }
 930     private static String setFloat(int r, String expr) { return "f"+r+"=Float.floatToRawIntBits("+expr+");"; }
 931     private static String setDouble(int r, String expr) {
 932         return "{ long l = Double.doubleToLongBits("+expr+"); "+
 933             "f"+(r+1)+" = (int)(l >>> 32); f"+r+" = (int)l; }";
 934     }
 935 }
 936