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