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         if(singleFloat) throw new Exn("JavaSourceCompiler doesn't support singleFloat");
  37         String packageName;
  38         String className;
  39         if (fullClassName.indexOf('.') != -1) {
  40             packageName = fullClassName.substring(0, fullClassName.lastIndexOf('.'));
  41             className = fullClassName.substring(fullClassName.lastIndexOf('.') + 1);
  42         } else {
  43             className = fullClassName;
  44             packageName = null;
  45         }
  46
  47         p("/* This file was generated from " + source + " by Mips2Java on " + dateTime() + " */");
  48         if (packageName != null) p("package " + packageName + ";");
  49         if(runtimeStats) p("import java.util.*;");
  50         p();
  51         p("public final class " + className + " extends " + runtimeClass + " {");
  52         indent++;
  53
  54         p("/* program counter */");
  55         p("private int pc = 0;");
  56         if(debugCompiler)
  57             p("private int lastPC = 0;");
  58         p();
  59         p("/* General Purpose registers */");
  60         p("private final static int r0 = 0;");
  61         p("private int      r1,  r2,  r3,  r4,  r5,  r6,  r7,");
  62         p("            r8,  r9,  r10, r11, r12, r13, r14, r15,");
  63         p("            r16, r17, r18, r19, r20, r21, r22, r23,");
  64         p("            r24, r25, r26, r27, r28, r29, r30, r31,");
  65         p("            hi = 0, lo = 0;");
  66         p("/* FP registers */");
  67         p("private int f0,  f1,  f2,  f3,  f4,  f5,  f6,  f7,");
  68         p("            f8,  f9,  f10, f11, f12, f13, f14, f15,");
  69         p("            f16, f17, f18, f19, f20, f21, f22, f23,");
  70         p("            f24, f25, f26, f27, f28, f29, f30, f31;");
  71         p("/* FP Control Register */");
  72         p("private int fcsr = 0;");
  73         p();
  74
  75         if(onePage) p("private final int[] page = readPages[0];");
  76
  77         // Generate main body functions (run_XXXX() blocks, _data[] arrays, etc)
  78         int highestAddr = 0;
  79
  80         for(int i=0;i<elf.sheaders.length;i++) {
  81             ELF.SHeader sheader = elf.sheaders[i];
  82             String name = sheader.name;
  83             // if this section doesn't get loaded into our address space don't worry about it
  84             if(sheader.addr == 0x0) continue;
  85
  86             highestAddr = Math.max(highestAddr, sheader.addr + sheader.size);
  87
  88             if(name.equals(".text"))
  89                 emitText(sheader.addr, new DataInputStream(sheader.getInputStream()),sheader.size);
  90             else if(name.equals(".data") || name.equals(".sdata") || name.equals(".rodata") || name.equals(".ctors") || name.equals(".dtors"))
  91                 emitData(sheader.addr, new DataInputStream(sheader.getInputStream()), sheader.size,name.equals(".rodata"));
  92             else if(name.equals(".bss") || name.equals(".sbss"))
  93                 emitBSS(sheader.addr,sheader.size);
  94             else
  95                 throw new Exn("Unknown segment: " + name);
  96         }
  97         p();
  98
  99         pblock(classLevel);
 100         p();
 101
 102         // Trampoline (dispatch calls to the appropriate run_XXX() methods
 103         p("private final void trampoline() throws ExecutionException {");
 104         indent++;
 105         p("while(state == RUNNING) {");
 106         indent++;
 107         p("switch(pc>>>" + methodShift+ ") {");
 108         //p("switch(pc&" + toHex(methodMask) + ") {");
 109         indent++;
 110         pblock(runs);
 111         p("default: throw new ExecutionException(\"invalid address 0x\" + Long.toString(this.pc&0xffffffffL,16) + \": r2: \" + r2);");
 112         indent--; p("}");
 113         indent--; p("}");
 114         indent--; p("}");
 115         p();
 116
 117         // Constructor
 118         p("public " + className + "() {");
 119         indent++;
 120         p("super(" + pageSize + "," + totalPages + ");");
 121         pblock(inits);
 122         indent--;
 123         p("}");
 124         p();
 125
 126         p("protected int entryPoint() { return " + toHex(elf.header.entry) + "; }");
 127         p("protected int heapStart() { return " + toHex(highestAddr) + "; }");
 128         p("protected int gp() { return " + toHex(gp.addr) + "; }");
 129         if(userInfo != null) {
 130             p("protected int userInfoBase() { return " + toHex(userInfo.addr) + "; }");
 131             p("protected int userInfoSize() { return " + toHex(userInfo.size) + "; }");
 132         }
 133
 134         // main() function
 135         p("public static void main(String[] args) throws Exception {");
 136         indent++;
 137         p("" + className + " me = new " + className + "();");
 138         p("int status = me.run(\"" + fullClassName + "\",args);");
 139         if(runtimeStats) p("me.printStats();");
 140         p("System.exit(status);");
 141         indent--;
 142         p("}");
 143         p();
 144
 145         // Runtime abstract methods
 146         p("protected void _execute() throws ExecutionException { trampoline(); }");
 147         p();
 148
 149         p("protected void setCPUState(CPUState state) {");
 150         indent++;
 151         for(int i=1;i<32;i++) p("r" + i + "=state.r[" + i + "];");
 152         for(int i=0;i<32;i++) p("f" + i + "=state.f[" + i + "];");
 153         p("hi=state.hi; lo=state.lo; fcsr=state.fcsr;");
 154         p("pc=state.pc;");
 155         indent--;
 156         p("}");
 157         p("protected void getCPUState(CPUState state) {");
 158         indent++;
 159         for(int i=1;i<32;i++) p("state.r[" + i + "]=r" + i+ ";");
 160         for(int i=0;i<32;i++) p("state.f[" + i + "]=f" + i +";");
 161         p("state.hi=hi; state.lo=lo; state.fcsr=fcsr;");
 162         p("state.pc=pc;");
 163         indent--;
 164         p("}");
 165         p();
 166
 167         if(supportCall) {
 168             p("private static final " + hashClass + " symbols = new " + hashClass + "();");
 169             p("static {");
 170             indent++;
 171             ELF.Symbol[] symbols = elf.getSymtab().symbols;
 172             for(int i=0;i<symbols.length;i++) {
 173                 ELF.Symbol s = symbols[i];
 174                 if(s.type == ELF.Symbol.STT_FUNC && s.binding == ELF.Symbol.STB_GLOBAL && (s.name.equals("_call_helper") || !s.name.startsWith("_")))
 175                     p("symbols.put(\"" + s.name + "\",new Integer(" + toHex(s.addr) + "));");
 176             }
 177             indent--;
 178             p("}");
 179             p("public int lookupSymbol(String symbol) { Integer i = (Integer) symbols.get(symbol); return i==null ? -1 : i.intValue(); }");
 180             p();
 181         }
 182
 183         // Runtime stats
 184         if(runtimeStats) {
 185             p("private HashMap counters = new HashMap();");
 186             p("private void inc(String k) { Long i = (Long)counters.get(k); counters.put(k,new Long(i==null ? 1 : i.longValue() + 1)); }");
 187             p("private void printStats() {");
 188             p(" Iterator i = new TreeSet(counters.keySet()).iterator();");
 189             p(" while(i.hasNext()) { Object o = i.next(); System.err.println(\"\" + o + \": \" + counters.get(o)); }");
 190             p("}");
 191             p();
 192         }
 193
 194         indent--;
 195         p("}");
 196     }
 197
 198     private int startOfMethod = 0;
 199     private int endOfMethod = 0;
 200
 201     private void startMethod(int addr) {
 202         addr &= ~(maxBytesPerMethod-1);
 203         startOfMethod = addr;
 204         endOfMethod = addr + maxBytesPerMethod;
 205         String methodName = "run_" + Long.toString(addr & 0xffffffffL, 16);
 206         runs.append(indents[4] + "case " + toHex(addr>>>methodShift) + ": " + methodName + "(); break; \n");
 207         //runs.append(indents[4] + "case " + toHex(addr&methodMask) + ": " + methodName + "(); break; \n");
 208
 209         p("private final void " + methodName + "() throws ExecutionException { /"+"* " + toHex(addr) + " - " + toHex(endOfMethod) + " *" + "/");
 210         indent++;
 211         p("int addr, tmp;");
 212         p("for(;;) {");
 213         indent++;
 214         p("switch(pc) {");
 215         indent++;
 216     }
 217
 218     private void endMethod() { endMethod(endOfMethod); }
 219     private void endMethod(int lastAddr) {
 220         if(startOfMethod == 0) return;
 221         // We should be able to use if(!unreachable) here (i think)
 222         // This isn't strictly necessary; its just here to work around unreachable code errors
 223         p("case " + toHex(lastAddr) + ":");
 224         indent++;
 225         p("pc=" + constant(lastAddr) + ";");
 226         leaveMethod();
 227         indent--;
 228         if(debugCompiler)
 229             p("default: throw new ExecutionException(\"invalid address 0x\" + Long.toString(pc&0xffffffffL,16)  + \" (got here from 0x\" + Long.toString(lastPC&0xffffffffL,16)+\")\");");
 230         else
 231             p("default: throw new ExecutionException(\"invalid address 0x\" + Long.toString(pc&0xffffffffL,16));");
 232         indent--;
 233         p("}"); // end switch
 234         p("/* NOT REACHED */");
 235         indent--;
 236         p("}"); // end for
 237         indent--;
 238         p("}"); // end method
 239         endOfMethod = startOfMethod = 0;
 240     }
 241
 242     private HashMap relativeAddrs = new HashMap();
 243     private String constant(int target) {
 244         if(target >= 4096 && lessConstants) {
 245             int n = target & ~1023;
 246             String var = "N_" + toHex8(n);
 247             if(relativeAddrs.get(new Integer(n)) == null) {
 248                 relativeAddrs.put(new Integer(n),Boolean.TRUE);
 249                 classLevel.append(indents[1] + "private static int " + var + " = " + toHex(n) + ";\n");
 250             }
 251             return "(" + var + " + " + toHex(target - n) + ")";
 252         } else {
 253             return toHex(target);
 254         }
 255     }
 256
 257     private void branch(int pc, int target) {
 258         if(debugCompiler) p("lastPC = " + toHex(pc) + ";");
 259         p("pc=" + constant(target) + ";");
 260         if(target == 0)
 261             p("throw new ExecutionException(\"Branch to addr 0x0\");");
 262         else if((pc&methodMask) == (target&methodMask))
 263             p("continue;");
 264         else if(assumeTailCalls)
 265             p("run_" +  Long.toString((target&methodMask)&0xffffffffL, 16) + "(); return;");
 266         else
 267             leaveMethod();
 268     }
 269
 270     private void leaveMethod() {
 271         p("return;");
 272     }
 273
 274     private boolean textDone;
 275     private void emitText(int addr, DataInputStream dis, int size) throws Exn,IOException {
 276         if(textDone) throw new Exn("Multiple text segments");
 277         textDone = true;
 278
 279         if((addr&3)!=0 || (size&3)!=0) throw new Exn("Section on weird boundaries");
 280         int count = size/4;
 281         int nextInsn = dis.readInt();
 282         if(nextInsn == -1) throw new Error("Actually read -1 at " + toHex(addr));
 283         int insn;
 284
 285         for(int i=0;i<count;i++,addr+=4) {
 286             insn = nextInsn;
 287             nextInsn = (i == count-1) ? -1 : dis.readInt();
 288             if(addr >= endOfMethod) { endMethod(); startMethod(addr); }
 289             if(jumpableAddresses==null || addr == startOfMethod || jumpableAddresses.contains(new Integer(addr))) {
 290                 p("case " + toHex(addr) + ":");
 291                 unreachable = false;
 292             } else if(unreachable) {
 293                 continue;
 294             } else if(debugCompiler) {
 295                 p("/" + "* pc = " + toHex(addr) + "*" + "/");
 296             }
 297             indent++;
 298             emitInstruction(addr,insn,nextInsn);
 299             indent--;
 300         }
 301         endMethod(addr);
 302         p();
 303         dis.close();
 304     }
 305
 306     private int initDataCount = 0;
 307     private void emitData(int addr, DataInputStream dis, int size, boolean readOnly) throws Exn,IOException {
 308         if((addr&3)!=0 || (size&3)!=0) throw new Exn("Data section on weird boundaries");
 309         int last = addr + size;
 310         while(addr < last) {
 311             int segSize = Math.min(size,28000); // must be a multiple of 56
 312             StringBuffer sb = new StringBuffer();
 313             for(int i=0;i<segSize;i+=7) {
 314                 long l = 0;
 315                 for(int j=0;j<7;j++) {
 316                     l <<= 8;
 317                     byte b = (i+j < size) ? dis.readByte() : 1;
 318                     l |= (b & 0xffL);
 319                 }
 320                 for(int j=0;j<8;j++) {
 321                     char c = (char) ((l>>>(7*(7-j)))&0x7f);
 322                     if(c=='\n') sb.append("\\n");
 323                     else if(c=='\r') sb.append("\\r");
 324                     else if(c=='\\') sb.append("\\\\");
 325                     else if(c=='"') sb.append("\\\"");
 326                     else if(c >= 32 && c <= 126) sb.append(c);
 327                     else sb.append("\\" +  toOctal3(c));
 328                 }
 329             }
 330             String varname =  "_data" + (++initDataCount);
 331             p("private static final int[] " + varname + " = decodeData(\"" + sb.toString() + "\"," + toHex(segSize/4) + ");");
 332             inits.append(indents[2] + "initPages(" + varname +"," + toHex(addr) + "," + (readOnly?"true":"false") + ");\n");
 333             addr += segSize;
 334             size -= segSize;
 335         }
 336         dis.close();
 337     }
 338
 339     private void emitBSS(int addr, int size) throws Exn {
 340         if((addr&3)!=0) throw new Exn("BSS section on weird boundaries");
 341         size = (size+3)&~3;
 342         int count = size/4;
 343         inits.append(indents[2] + "clearPages(" + toHex(addr) + "," + toHex(count) + ");\n");
 344     }
 345
 346     // True if the current code path is unreachable (any instruction with a case statement is reachable)
 347     private boolean unreachable = false;
 348
 349     private void emitInstruction(int pc, int insn, int nextInsn) throws IOException,Exn {
 350         if(insn == -1) throw new Error("insn is -1");
 351
 352         int op = (insn >>> 26) & 0xff;                 // bits 26-31
 353         int rs = (insn >>> 21) & 0x1f;                 // bits 21-25
 354         int rt = (insn >>> 16) & 0x1f;                 // bits 16-20
 355         int ft = (insn >>> 16) & 0x1f;
 356         int rd = (insn >>> 11) & 0x1f;                 // bits 11-15
 357         int fs = (insn >>> 11) & 0x1f;
 358         int shamt = (insn >>> 6) & 0x1f;               // bits 6-10
 359         int fd = (insn >>> 6) & 0x1f;
 360         int subcode = insn & 0x3f;                     // bits 0-5
 361
 362         int jumpTarget = (insn & 0x03ffffff);          // bits 0-25
 363         int unsignedImmediate = insn & 0xffff;
 364         int signedImmediate = (insn << 16) >> 16;
 365         int branchTarget = signedImmediate;
 366
 367         int tmp; // temporaries
 368
 369         //if(pc%64==0) p("System.err.println(\"Executing: " + toHex(pc) + "\");");
 370         //p("/" + "*" + (pc == -1 ? "Delay Slot"  : toHex(pc)) + " *" + "/ ");
 371         if(pc==-1) p("/" + "* Next insn is delay slot *" + "/ ");
 372
 373         if(runtimeStats && op != 0) p("inc(\"opcode: " + op + "\");");
 374         switch(op) {
 375             case 0: {
 376                 if(runtimeStats && insn != 0) p("inc(\"opcode: 0/" + subcode + "\");");
 377                 switch(subcode) {
 378                     case 0: // SLL
 379                         if(insn != 0)
 380                             p( "r"+rd+" = r"+rt+" << "+shamt+";");
 381                         break;
 382                     case 2: // SRL
 383                         p( "r"+rd+" = r"+rt+" >>> "+shamt+";");
 384                         break;
 385                     case 3: // SRA
 386                         p( "r"+rd+" = r"+rt+" >> "+shamt+";");
 387                         break;
 388                     case 4: // SLLV
 389                         p( "r"+rd+" = r"+rt+" << (r"+rs+"&0x1f);");
 390                         break;
 391                     case 6: // SRLV
 392                         p( "r"+rd+" = r"+rt+" >>> (r"+rs+"&0x1f);");
 393                         break;
 394                     case 7: // SRAV
 395                         p( "r"+rd+" = r"+rt+" >> (r"+rs+"&0x1f);");
 396                         break;
 397                     case 8: // JR
 398                         if(pc == -1) throw new Error("pc modifying insn in delay slot");
 399                         emitInstruction(-1,nextInsn,-1);
 400                         if(debugCompiler) p("lastPC = " + toHex(pc) + ";");
 401                         p("pc=r" + rs + ";");
 402                         leaveMethod();
 403                         unreachable = true;
 404                         break;
 405                     case 9: // JALR
 406                         if(pc == -1) throw new Error("pc modifying insn in delay slot");
 407                         emitInstruction(-1,nextInsn,-1);
 408                         if(debugCompiler) p("lastPC = " + toHex(pc) + ";");
 409                         p("pc=r" + rs + ";");
 410                         p("r" + RA + "=" + constant(pc+8 /*skip this insn and delay slot*/) + ";");
 411                         leaveMethod();
 412                         unreachable = true;
 413                         break;
 414                     case 12: // SYSCALL
 415                         p("pc = " + toHex(pc) + ";");
 416                         p( "r"+V0+" = syscall(r"+V0+",r"+A0+",r"+A1+",r"+A2+",r"+A3+",r"+T0+",r"+T1+");");
 417                         p("if (state != RUNNING) {");
 418                             indent++;
 419                             p("pc = " + toHex(pc+4) + ";");
 420                             leaveMethod();
 421                             indent--;
 422                         p("}");
 423                         break;
 424                     case 13: // BREAK
 425                         p( "throw new ExecutionException(\"Break\");");
 426                         break;
 427                     case 16: // MFHI
 428                         p( "r"+rd+" = hi;");
 429                         break;
 430                     case 17: // MTHI
 431                         p( "hi = r"+rs+";");
 432                         break;
 433                     case 18: // MFLO
 434                         p( "r"+rd+" = lo;");
 435                         break;
 436                     case 19: // MTLO
 437                         p( "lo = r"+rs+";");
 438                         break;
 439                     case 24: // MULT
 440                         p( "{ long hilo = (long)(r"+rs+") * ((long)r"+rt+"); " +
 441                              "hi = (int) (hilo >>> 32); " +
 442                              "lo = (int) hilo; }");
 443                         break;
 444                     case 25: // MULTU
 445                         p( "{ long hilo = (r"+rs+" & 0xffffffffL) * (r"+rt+" & 0xffffffffL); " +
 446                              "hi = (int) (hilo >>> 32); " +
 447                              "lo = (int) hilo; } ");
 448                         break;
 449                     case 26: // DIV
 450                         p( "hi = r"+rs+"%r"+rt+"; lo = r"+rs+"/r"+rt+";");
 451                         break;
 452                     case 27: // DIVU
 453                         p("if(r"+rt+"!=0) {");
 454                         p( "hi = (int)((r"+rs+" & 0xffffffffL) % (r"+rt+" & 0xffffffffL)); " +
 455                              "lo = (int)((r"+rs+" & 0xffffffffL) / (r"+rt+" & 0xffffffffL));");
 456                         p("}");
 457                         break;
 458                     case 32: // ADD
 459                          throw new Exn("ADD (add with oveflow trap) not suported");
 460                         /*This must trap on overflow
 461                         p( "r"+rd+" = r"+rs+" + r"+rt+";");
 462                         break;*/
 463                     case 33: // ADDU
 464                         p( "r"+rd+" = r"+rs+" + r"+rt+";");
 465                         break;
 466                     case 34: // SUB
 467                          throw new Exn("SUB (add with oveflow trap) not suported");
 468                         /*This must trap on overflow
 469                         p( "r"+rd+" = r"+rs+" - r"+rt+";");
 470                         break;*/
 471                     case 35: // SUBU
 472                         p( "r"+rd+" = r"+rs+" - r"+rt+";");
 473                         break;
 474                     case 36: // AND
 475                         p( "r"+rd+" = r"+rs+" & r"+rt+";");
 476                         break;
 477                     case 37: // OR
 478                         p( "r"+rd+" = r"+rs+" | r"+rt+";");
 479                         break;
 480                     case 38: // XOR
 481                         p( "r"+rd+" = r"+rs+" ^ r"+rt+";");
 482                         break;
 483                     case 39: // NOR
 484                         p( "r"+rd+" = ~(r"+rs+" | r"+rt+");");
 485                         break;
 486                     case 42: // SLT
 487                         p( "r"+rd+" = r"+rs+" < r"+rt+" ? 1 : 0;");
 488                         break;
 489                     case 43: // SLTU
 490                         p( "r"+rd+" = ((r"+rs+" & 0xffffffffL) < (r"+rt+" & 0xffffffffL)) ? 1 : 0;");
 491                         break;
 492                     default:
 493                         throw new RuntimeException("Illegal instruction 0/" + subcode);
 494                 }
 495                 break;
 496             }
 497             case 1: {
 498                 switch(rt) {
 499                     case 0: // BLTZ
 500                         if(pc == -1) throw new Error("pc modifying insn in delay slot");
 501                         p("if(r" + rs + " < 0) {");
 502                             indent++;
 503                             emitInstruction(-1,nextInsn,-1);
 504                             branch(pc,pc+branchTarget*4+4);
 505                             indent--;
 506                         p("}");
 507                         break;
 508                     case 1: // BGEZ
 509                         if(pc == -1) throw new Error("pc modifying insn in delay slot");
 510                         p("if(r" + rs + " >= 0) {");
 511                             indent++;
 512                             emitInstruction(-1,nextInsn,-1);
 513                             branch(pc,pc+branchTarget*4+4);
 514                             indent--;
 515                         p("}");
 516                         break;
 517                     case 16: // BLTZAL
 518                         if(pc == -1) throw new Error("pc modifying insn in delay slot");
 519                         p("if(r" + rs + " < 0) {");
 520                             indent++;
 521                             emitInstruction(-1,nextInsn,-1);
 522                             p("r" + RA + "=" + constant(pc+8 /*skip this insn and delay slot*/) + ";");
 523                             branch(pc,pc+branchTarget*4+4);
 524                             indent--;
 525                         p("}");
 526                         break;
 527                     case 17: // BGEZAL
 528                         if(pc == -1) throw new Error("pc modifying insn in delay slot");
 529                         p("if(r" + rs + " >= 0) {");
 530                             indent++;
 531                             emitInstruction(-1,nextInsn,-1);
 532                             p("r" + RA + "=" + constant(pc+8 /*skip this insn and delay slot*/) + ";");
 533                             branch(pc,pc+branchTarget*4+4);
 534                             indent--;
 535                         p("}");
 536                         break;
 537                     default:
 538                         throw new RuntimeException("Illegal Instruction 1/" + rt);
 539                 }
 540                 break;
 541             }
 542             case 2: { // J
 543                 if(pc == -1) throw new Error("pc modifying insn in delay slot");
 544                 emitInstruction(-1,nextInsn,-1);
 545                 branch(pc,(pc&0xf0000000)|(jumpTarget << 2));
 546                 unreachable = true;
 547                 break;
 548             }
 549             case 3: { // JAL
 550                 if(pc == -1) throw new Error("pc modifying insn in delay slot");
 551                 int target = (pc&0xf0000000)|(jumpTarget << 2);
 552                 emitInstruction(-1,nextInsn,-1);
 553                 p("r" + RA + "=" + constant(pc+8 /*skip this insn and delay slot*/) + ";");
 554                 branch(pc, target);
 555                 unreachable = true;
 556                 break;
 557             }
 558             case 4: // BEQ
 559                 if(pc == -1) throw new Error("pc modifying insn in delay slot");
 560                 p("if(r" + rs + " == r" + rt + ") {");
 561                     indent++;
 562                     emitInstruction(-1,nextInsn,-1);
 563                     branch(pc,pc+branchTarget*4+4);
 564                     indent--;
 565                 p("}");
 566                 break;
 567             case 5: // BNE
 568                 if(pc == -1) throw new Error("pc modifying insn in delay slot");
 569                 p("if(r" + rs + " != r" + rt + ") {");
 570                     indent++;
 571                     emitInstruction(-1,nextInsn,-1);
 572                     branch(pc,pc+branchTarget*4+4);
 573                     indent--;
 574                 p("}");
 575                 break;
 576             case 6: //BLEZ
 577                 if(pc == -1) throw new Error("pc modifying insn in delay slot");
 578                 p("if(r" + rs + " <= 0) {");
 579                     indent++;
 580                     emitInstruction(-1,nextInsn,-1);
 581                     branch(pc,pc+branchTarget*4+4);
 582                     indent--;
 583                 p("}");
 584                 break;
 585             case 7: //BGTZ
 586                 if(pc == -1) throw new Error("pc modifying insn in delay slot");
 587                 p("if(r" + rs + " > 0) {");
 588                     indent++;
 589                     emitInstruction(-1,nextInsn,-1);
 590                     branch(pc,pc+branchTarget*4+4);
 591                     indent--;
 592                 p("}");
 593                 break;
 594             case 8: // ADDI
 595                 p( "r"+rt+" = r"+rs+" + "+signedImmediate +";");
 596                 break;
 597             case 9: // ADDIU
 598                 p( "r"+rt+" = r"+rs+" + "+signedImmediate+";");
 599                 break;
 600             case 10: // SLTI
 601                 p( "r"+rt+" = r"+rs+" < "+signedImmediate+" ? 1 : 0;");
 602                 break;
 603             case 11: // SLTIU
 604                 p( "r"+rt+" = (r"+rs+"&0xffffffffL) < ("+signedImmediate+"&0xffffffffL) ? 1 : 0;");
 605                 break;
 606             case 12: // ANDI
 607                 p( "r"+rt+" = r"+rs+" & "+unsignedImmediate+";");
 608                 break;
 609             case 13: // ORI
 610                 p( "r"+rt+" = r"+rs+" | "+unsignedImmediate+";");
 611                 break;
 612             case 14: // XORI
 613                 p( "r"+rt+" = r"+rs+" ^ "+unsignedImmediate+";");
 614                 break;
 615             case 15: // LUI
 616                 p( "r"+rt+" = "+unsignedImmediate+" << 16;");
 617                 break;
 618             case 16:
 619                 throw new Exn("TLB/Exception support not implemented");
 620             case 17: { // FPU
 621                 switch(rs) {
 622                     case 0: // MFC.1
 623                         p( "r"+rt+" = f"+rd+";");
 624                         break;
 625                     case 2: // CFC.1
 626                         if(fs != 31) throw new Exn("FCR " + fs + " unavailable");
 627                         p( "r"+rt+" = fcsr;");
 628                         break;
 629                     case 4: // MTC.1
 630                         p( "f"+rd+" = r"+rt+";");
 631                         break;
 632                     case 6: // CTC.1
 633                         if(fs != 31) throw new Exn("FCR " + fs + " unavailable");
 634                         p( "fcsr = r"+rt+";");
 635                         break;
 636                     case 8: {// BC1F, BC1T
 637                         tmp = (insn>>>16)&1;
 638                         p("if(((fcsr&0x800000)!=0) == (" + tmp + "!=0)) {");
 639                             indent++;
 640                             emitInstruction(-1,nextInsn,-1);
 641                             branch(pc,pc+branchTarget*4+4);
 642                             indent--;
 643                         p("}");
 644                         break;
 645                     }
 646                     case 16: {  // Single
 647                         switch(subcode) {
 648                             case 0: // ADD.S
 649                                 p(setFloat(fd,getFloat(fs)+"+"+getFloat(ft)));
 650                                 break;
 651                             case 1: // SUB.S
 652                                 p(setFloat(fd,getFloat(fs)+"-"+getFloat(ft)));
 653                                 break;
 654                             case 2: // MUL.S
 655                                 p(setFloat(fd,getFloat(fs)+"*"+getFloat(ft)));
 656                                 break;
 657                             case 3: // DIV.S
 658                                 p(setFloat(fd,getFloat(fs)+"/"+getFloat(ft)));
 659                                 break;
 660                             case 5: // ABS.S
 661                                 p(setFloat(fd,"Math.abs("+getFloat(fs)+")"));
 662                                 break;
 663                             case 6: // MOV.S
 664                                 p("f"+fd+" = f"+fs+"; // MOV.S");
 665                                 break;
 666                             case 7: // NEG.S
 667                                 p(setFloat(fd,"-"+getFloat(fs)));
 668                                 break;
 669                             case 33: // CVT.D.S
 670                                 p(setDouble(fd,"(float)"+getFloat(fs)));
 671                                 break;
 672                             case 36: // CVT.W.D
 673                                 p("switch(fcsr & 3) {");
 674                                     indent++;
 675                                     p("case 0: f"+fd+" = (int)Math.floor("+getFloat(fs)+"+0.5); break; // Round to nearest");
 676                                     p("case 1: f"+fd+" = (int)"+getFloat(fs)+"; break; // Round towards zero");
 677                                     p("case 2: f"+fd+" = (int)Math.ceil("+getFloat(fs)+"); break; // Round towards plus infinity");
 678                                     p("case 3: f"+fd+" = (int)Math.floor("+getFloat(fs)+"); break; // Round towards minus infinity");
 679                                     indent--;
 680                                 p("}");
 681                                 break;
 682                             case 50: // C.EQ.S
 683                                 p("fcsr = (fcsr&~0x800000) | (("+getFloat(fs)+"=="+getFloat(ft)+") ? 0x800000 : 0x000000);");
 684                                 break;
 685                             case 60: // C.LT.S
 686                                 p("fcsr = (fcsr&~0x800000) | (("+getFloat(fs)+"<"+getFloat(ft)+") ? 0x800000 : 0x000000);");
 687                                 break;
 688                             case 62: // C.LE.S
 689                                 p("fcsr = (fcsr&~0x800000) | (("+getFloat(fs)+"<="+getFloat(ft)+") ? 0x800000 : 0x000000);");
 690                                 break;
 691                             default: throw new Exn("Invalid Instruction 17/" + rs + "/" + subcode);
 692                         }
 693                         break;
 694                     }
 695                     case 17: { // Double
 696                         switch(subcode) {
 697                             case 0: // ADD.D
 698                                 p(setDouble(fd,getDouble(fs)+"+"+getDouble(ft)));
 699                                 break;
 700                             case 1: // SUB.D
 701                                 p(setDouble(fd,getDouble(fs)+"-"+getDouble(ft)));
 702                                 break;
 703                             case 2: // MUL.D
 704                                 p(setDouble(fd,getDouble(fs)+"*"+getDouble(ft)));
 705                                 break;
 706                             case 3: // DIV.D
 707                                 p(setDouble(fd,getDouble(fs)+"/"+getDouble(ft)));
 708                                 break;
 709                             case 5: // ABS.D
 710                                 p(setDouble(fd,"Math.abs("+getDouble(fs)+")"));
 711                                 break;
 712                             case 6: // MOV.D
 713                                 p("f"+fd+" = f"+fs+";");
 714                                 p("f"+(fd+1)+" = f"+(fs+1)+";");
 715                                 break;
 716                             case 7: // NEG.D
 717                                 p(setDouble(fd,"-"+getDouble(fs)));
 718                                 break;
 719                             case 32: // CVT.S.D
 720                                 p(setFloat(fd,"(float)"+getDouble(fs)));
 721                                 break;
 722                             case 36: // CVT.W.D
 723                                 p("switch(fcsr & 3) {");
 724                                     indent++;
 725                                     p("case 0: f"+fd+" = (int)Math.floor("+getDouble(fs)+"+0.5); break; // Round to nearest");
 726                                     p("case 1: f"+fd+" = (int)"+getDouble(fs)+"; break; // Round towards zero");
 727                                     p("case 2: f"+fd+" = (int)Math.ceil("+getDouble(fs)+"); break; // Round towards plus infinity");
 728                                     p("case 3: f"+fd+" = (int)Math.floor("+getDouble(fs)+"); break; // Round towards minus infinity");
 729                                     indent--;
 730                                 p("}");
 731                                 break;
 732                             case 50: // C.EQ.D
 733                                 p("fcsr = (fcsr&~0x800000) | (("+getDouble(fs)+"=="+getDouble(ft)+") ? 0x800000 : 0x000000);");
 734                                 break;
 735                             case 60: // C.LT.D
 736                                 p("fcsr = (fcsr&~0x800000) | (("+getDouble(fs)+"<"+getDouble(ft)+") ? 0x800000 : 0x000000);");
 737                                 break;
 738                             case 62: // C.LE.D
 739                                 p("fcsr = (fcsr&~0x800000) | (("+getDouble(fs)+"<="+getDouble(ft)+") ? 0x800000 : 0x000000);");
 740                                 break;
 741                             default: throw new Exn("Invalid Instruction 17/" + rs + "/" + subcode);
 742                         }
 743                         break;
 744                     }
 745                     case 20: { // Integer
 746                         switch(subcode) {
 747                             case 32: // CVT.S.W
 748                                 p(" // CVS.S.W");
 749                                 p(setFloat(fd,"((float)f"+fs+")"));
 750                                 break;
 751                             case 33: // CVT.D.W
 752                                 p(setDouble(fd,"((double)f"+fs+")"));
 753                                 break;
 754                             default: throw new Exn("Invalid Instruction 17/" + rs + "/" + subcode);
 755                         }
 756                         break;
 757                     }
 758                     default:
 759                         throw new Exn("Invalid Instruction 17/" + rs);
 760                 }
 761                 break;
 762             }
 763             case 18: case 19:
 764                 throw new Exn("coprocessor 2 and 3 instructions not available");
 765             case 32: { // LB
 766                 if(runtimeStats) p("inc(\"LB\");");
 767                 p("addr=r" + rs +"+"+signedImmediate + ";");
 768                 memRead("addr","tmp");
 769                 p("tmp = (tmp>>>(((~addr)&3)<<3)) & 0xff;");
 770                 p("if((tmp&0x80)!=0) tmp |= 0xffffff00; /* sign extend */");
 771                 p("r"+rt+" = tmp;");
 772                 break;
 773             }
 774             case 33: { // LH
 775                 if(runtimeStats) p("inc(\"LH\");");
 776                 p("addr=r" + rs +"+"+signedImmediate + ";");
 777                 memRead("addr","tmp");
 778                 p("tmp = (tmp>>>(((~addr)&2)<<3)) & 0xffff;");
 779                 p("if((tmp&0x8000)!=0) tmp |= 0xffff0000; /* sign extend */");
 780                 p("r"+rt+" = tmp;");
 781                 break;
 782             }
 783             case 34: { // LWL;
 784                 p("addr=r" + rs +"+"+signedImmediate + ";");
 785                 memRead("addr","tmp");
 786                 p("r" + rt + " = (r"+rt+"&(0x00ffffff>>>(((~addr)&3)<<3)))|(tmp<<((addr&3)<<3));");
 787                 break;
 788                 /*p("addr=r" + rs +"+"+signedImmediate + ";");
 789                 memRead("addr&~3","tmp");
 790                 p("switch(addr&3) {");
 791                 indent++;
 792                 p("case 0: r"+rt+" = (r"+rt+"&0x00000000)|(tmp<< 0); break;");
 793                 p("case 1: r"+rt+" = (r"+rt+"&0x000000ff)|(tmp<< 8); break;");
 794                 p("case 2: r"+rt+" = (r"+rt+"&0x0000ffff)|(tmp<<16); break;");
 795                 p("case 3: r"+rt+" = (r"+rt+"&0x00ffffff)|(tmp<<24); break;");
 796                 indent--;
 797                 p("}");
 798                 break;*/
 799             }
 800             case 35: // LW
 801                 if(runtimeStats) p("inc(\"LW\");");
 802                 memRead("r" + rs +"+"+signedImmediate,"r"+rt);
 803                 break;
 804             case 36: { // LBU
 805                 p("addr=r" + rs +"+"+signedImmediate + ";");
 806                 memRead("addr","tmp");
 807                 p("tmp = (tmp>>>(((~addr)&3)<<3)) & 0xff;");
 808                 p("r"+rt+" = tmp;");
 809                 break;
 810             }
 811             case 37: { // LHU
 812                 p("addr=r" + rs +"+"+signedImmediate + ";");
 813                 memRead("addr","tmp");
 814                 p("tmp = (tmp>>>(((~addr)&2)<<3)) & 0xffff;");
 815                 p("r"+rt+" = tmp;");
 816                 break;
 817             }
 818             case 38: { // LWR
 819                 p("addr=r" + rs +"+"+signedImmediate + ";");
 820                 memRead("addr","tmp");
 821                 p("r" + rt + " = (r"+rt+"&(0xffffff00<<((addr&3)<<3)))|(tmp>>>(((~addr)&3)<<3));");
 822                 break;
 823
 824                 /*p("addr=r" + rs +"+"+signedImmediate + ";");
 825                 memRead("addr&~3","tmp");
 826                 p("switch(addr&3) {");
 827                 indent++;
 828                 p("case 0: r"+rt+" = (r"+rt+"&0xffffff00)|(tmp>>>24); break;");
 829                 p("case 1: r"+rt+" = (r"+rt+"&0xffff0000)|(tmp>>>16); break;");
 830                 p("case 2: r"+rt+" = (r"+rt+"&0xff000000)|(tmp>>> 8); break;");
 831                 p("case 3: r"+rt+" = (r"+rt+"&0x00000000)|(tmp>>> 0); break;");
 832                 indent--;
 833                 p("}");
 834                 break;*/
 835
 836             }
 837             case 40: { // SB
 838                 if(runtimeStats) p("inc(\"SB\");");
 839                 p("addr=r" + rs +"+"+signedImmediate + ";");
 840                 memRead("addr","tmp");
 841                 p("tmp = (tmp&~(0xff000000>>>((addr&3)<<3)))|((r"+rt+"&0xff)<<(((~addr)&3)<<3));");
 842                 memWrite("addr","tmp");
 843                 break;
 844             }
 845             case 41: { // SH
 846                 if(runtimeStats) p("inc(\"SH\");");
 847                 p("addr=r" + rs +"+"+signedImmediate + ";");
 848                 memRead("addr","tmp");
 849                 p("tmp = (tmp&(0xffff<<((addr&2)<<3)))|((r" + rt + "&0xffff)<<(((~addr)&2)<<3));");
 850                 memWrite("addr","tmp");
 851                 break;
 852             }
 853             case 42: { // SWL
 854                 p(" // SWL");
 855                 p("addr=r" + rs +"+"+signedImmediate + ";");
 856                 memRead("addr","tmp");
 857                 p("tmp = (tmp&(0xffffff00<<(((~addr)&3)<<3)))|(r"+rt+">>>((addr&3)<<3));");
 858                 memWrite("addr","tmp");
 859                 break;
 860             }
 861             case 43: // SW
 862                 if(runtimeStats) p("inc(\"SW\");");
 863                 memWrite("r"+rs+"+"+signedImmediate,"r" + rt);
 864                 break;
 865             case 46: { // SWR
 866                 p(" // SWR");
 867                 p("addr=r" + rs +"+"+signedImmediate + ";");
 868                 memRead("addr","tmp");
 869                 p("tmp = (tmp&(0x00ffffff>>>((addr&3)<<3)))|(r"+rt+"<<(((~addr)&3)<<3));");
 870                 memWrite("addr","tmp");
 871                 break;
 872             }
 873             // Need to be atomic if threads
 874             case 48: // LWC0/LL
 875                 memRead("r"+rs+"+"+signedImmediate,"r"+rt);
 876                 break;
 877             case 49: // LWC1
 878                 memRead("r"+rs+"+"+signedImmediate,"f"+rt);
 879                 break;
 880             // Needs to be atomic if threads
 881             case 56: // SWC1/SC
 882                 memWrite("r"+rs+"+"+signedImmediate,"r"+rt);
 883                 p("r" + rt + "=1;");
 884                 break;
 885             case 57: // SWC1
 886                 memWrite("r"+rs+"+"+signedImmediate,"f"+rt);
 887                 break;
 888             default:
 889                 throw new Exn("Invalid Instruction: " + op + " at " + toHex(pc));
 890         }
 891     }
 892
 893     // Helper functions for emitText
 894     // NOTE: memWrite and memRead MUST discard the last two bits of addr
 895     private void memWrite(String addr, String target) {
 896         if(nullPointerCheck) p("nullPointerCheck(" + addr + ");");
 897         if(onePage)
 898             p("page[(" + addr + ")>>>2] = " + target + ";");
 899         else if(fastMem)
 900             p("writePages[("+addr+")>>>"+pageShift+"][(("+addr+")>>>2)&"+toHex((pageSize>>2)-1)+"] = " + target + ";");
 901         else
 902             p("unsafeMemWrite(" + addr + "," + target + ");");
 903     }
 904     private void memRead(String addr, String target) {
 905         if(nullPointerCheck) p("nullPointerCheck(" + addr + ");");
 906         if(onePage)
 907             p(target + "= page[(" + addr + ")>>>2];");
 908         else if(fastMem)
 909             p(target  + " = readPages[("+addr+")>>>"+pageShift+"][(("+addr+")>>>2)&"+toHex((pageSize>>2)-1)+"];");
 910         else
 911             p(target + " = unsafeMemRead(" + addr + ");");
 912     }
 913     private static String getFloat(int r) { return "(Float.intBitsToFloat(f"+r+"))"; }
 914     private static String getDouble(int r) {
 915         return "(Double.longBitsToDouble(((f"+(r+1)+"&0xffffffffL) << 32) | (f"+r+"&0xffffffffL)))";
 916     }
 917     private static String setFloat(int r, String expr) { return "f"+r+"=Float.floatToRawIntBits("+expr+");"; }
 918     private static String setDouble(int r, String expr) {
 919         return "{ long l = Double.doubleToLongBits("+expr+"); "+
 920             "f"+(r+1)+" = (int)(l >>> 32); f"+r+" = (int)l; }";
 921     }
 922 }
 923