src/org/ibex/nestedvm/ClassFileCompiler.java

   1 package org.ibex.nestedvm;
   2
   3 import java.io.*;
   4 import java.util.Hashtable;
   5
   6 import org.ibex.nestedvm.util.*;
   7
   8 import org.apache.bcel.generic.*;
   9
  10 // FEATURE: Use BCEL to do peephole optimization
  11 // FEATURE: Special mode to support single-precision only - regs are floats not ints
  12
  13 /* FEATURE: Span large binaries across several classfiles
  14  * We should be able to do this with no performance penalty
  15  * Every method in the inner classes is static and takes the main class as an arg
  16  * This makes them look just like methods in the main class because arg1 gets loaded into
  17  * local register 0
  18  */
  19
  20 /* FEATURE: smarter with local regs
  21  * Be even smarter with the use of local registers. We need to only load fields into
  22  * local regs when they are actually used and only write to fields if the regs could have
  23  * changed. This should allow us to put more regs in local vars. Right now putting all used
  24  * regs local vars makes code like this slower.
  25  *
  26  * void work(int a, int b) {
  27  *    if(a == b) {
  28  *       fast path
  29  *       return;
  30  *    }
  31  *    real work
  32  * }
  33  * Because all the regs used in "real work" are loaded/restored even for fast path
  34  */
  35
  36
  37 public class ClassFileCompiler extends Compiler implements org.apache.bcel.Constants  {
  38     /** The stream to write the compiled output to */
  39     private OutputStream os;
  40     private PrintStream warn = System.err;
  41
  42     private ClassGen cl;
  43     private ConstantPoolGen cp;
  44     private InstructionList clinitExtras = new InstructionList();
  45     private InstructionList initExtras = new InstructionList();
  46     private InstructionFactory fac;
  47
  48     // Handy wrappers around the BCEL functions
  49     private InstructionList insnList;
  50     private void selectMethod(MethodGen m) { insnList = m.getInstructionList(); }
  51     private void selectList(InstructionList l) { insnList = l; }
  52     private InstructionHandle a(Instruction i) { return insnList.append(i); }
  53     private BranchHandle a(BranchInstruction i) { return insnList.append(i); }
  54     private InstructionHandle a(InstructionList l) { return insnList.append(l); }
  55     private InstructionHandle a(CompoundInstruction c) { return insnList.append(c); }
  56
  57     // This works around a bug in InstructionList
  58     // FEATURE: fix this in bcel, send them a patch, etc
  59     private static class FixedInstructionList extends InstructionList {
  60         public void move(InstructionHandle start, InstructionHandle end, InstructionHandle target) {
  61             InstructionHandle extra = target != null && target == getEnd() ? append(InstructionConstants.NOP) : null;
  62             super.move(start,end,target);
  63             if(extra != null) try { delete(extra); } catch (TargetLostException e) { /* won't happen */ }
  64         }
  65     }
  66
  67     private MethodGen newMethod(int flags, Type ret, Type[] args, String name) {
  68         return new MethodGen(flags,ret,args,null,name,fullClassName,new FixedInstructionList(),cp);
  69     }
  70
  71     public ClassFileCompiler(String path, String className, OutputStream os) throws IOException { this(new Seekable.File(path),className,os); }
  72     public ClassFileCompiler(Seekable binary, String className, OutputStream os) throws IOException {
  73         super(binary,className);
  74         this.os = os;
  75     }
  76
  77     public void setWarnWriter(PrintStream warn) { this.warn = warn; }
  78
  79     protected void _go() throws Exn, IOException {
  80         if(lessConstants) throw new Exn("ClassFileCompiler doesn't support -o lessconstants");
  81         if(!pruneCases) throw new Exn("-o prunecases MUST be enabled for ClassFileCompiler");
  82
  83         // Class
  84         cl = new ClassGen(fullClassName,runtimeClass,source,ACC_SUPER|ACC_PUBLIC|ACC_FINAL,null);
  85         cp = cl.getConstantPool();
  86         fac = new InstructionFactory(cl,cp);
  87
  88         // Fields
  89         cl.addField(new FieldGen(ACC_PRIVATE,Type.INT,"pc",cp).getField());
  90         for(int i=1;i<32;i++)
  91             cl.addField(new FieldGen(ACC_PRIVATE,Type.INT,"r"+i,cp).getField());
  92         for(int i=0;i<32;i++)
  93             cl.addField(new FieldGen(ACC_PRIVATE,Type.INT,"f"+i,cp).getField());
  94
  95         cl.addField(new FieldGen(ACC_PRIVATE,Type.INT,"hi",cp).getField());
  96         cl.addField(new FieldGen(ACC_PRIVATE,Type.INT,"lo",cp).getField());
  97         cl.addField(new FieldGen(ACC_PRIVATE,Type.INT,"fcsr",cp).getField());
  98
  99         if(onePage) {
 100             cl.addField(new FieldGen(ACC_PRIVATE|ACC_FINAL,new ArrayType(Type.INT,1),"page",cp).getField());
 101
 102             selectList(initExtras);
 103             a(InstructionConstants.ALOAD_0);
 104             a(InstructionConstants.DUP);
 105             a(fac.createFieldAccess(fullClassName,"readPages",new ArrayType(Type.INT, 2), GETFIELD));
 106             pushConst(0);
 107             a(InstructionConstants.AALOAD);
 108             a(fac.createFieldAccess(fullClassName,"page",new ArrayType(Type.INT,1), PUTFIELD));
 109         }
 110
 111         if(supportCall)
 112             cl.addField(new FieldGen(ACC_PRIVATE|ACC_STATIC|ACC_FINAL,Type.getType("L"+hashClass.replace('.','/')+";"),"symbols",cp).getField());
 113
 114         int highestAddr = 0;
 115
 116         for(int i=0;i<elf.sheaders.length;i++) {
 117             ELF.SHeader sheader = elf.sheaders[i];
 118             String name = sheader.name;
 119             // if this section doesn't get loaded into our address space don't worry about it
 120             if(sheader.addr == 0x0) continue;
 121
 122             highestAddr = Math.max(highestAddr, sheader.addr + sheader.size);
 123
 124             if(name.equals(".text"))
 125                 emitText(sheader.addr, new DataInputStream(sheader.getInputStream()),sheader.size);
 126             else if(name.equals(".data") || name.equals(".sdata") || name.equals(".rodata") || name.equals(".ctors") || name.equals(".dtors"))
 127                 emitData(sheader.addr, new DataInputStream(sheader.getInputStream()), sheader.size,name.equals(".rodata"));
 128             else if(name.equals(".bss") || name.equals(".sbss"))
 129                 emitBSS(sheader.addr,sheader.size);
 130             else
 131                 throw new Exn("Unknown segment: " + name);
 132         }
 133
 134         ELF.SHeader text = elf.sectionWithName(".text");
 135
 136         // Trampoline
 137         MethodGen tramp = newMethod(ACC_PRIVATE,Type.VOID, Type.NO_ARGS, "trampoline");
 138         tramp.addException("org.ibex.nestedvm.Runtime$ExecutionException");
 139         selectMethod(tramp);
 140
 141         InstructionHandle start = a(InstructionConstants.ALOAD_0);
 142         a(fac.createFieldAccess(fullClassName,"state",Type.INT, GETFIELD));
 143         pushConst(Runtime.RUNNING);
 144         BranchInstruction stateCheck =  InstructionFactory.createBranchInstruction(IF_ICMPNE,null);
 145         a(stateCheck);
 146         a(InstructionConstants.ALOAD_0);
 147         a(InstructionConstants.ALOAD_0);
 148         a(fac.createFieldAccess(fullClassName,"pc",Type.INT, GETFIELD));
 149         pushConst(methodShift);
 150         a(InstructionConstants.IUSHR);
 151
 152         int beg = text.addr >>> methodShift;
 153         int end = ((text.addr + text.size + maxBytesPerMethod - 1) >>> methodShift);
 154
 155         // This data is redundant but BCEL wants it
 156         int[] matches = new int[end-beg];
 157         for(int i=beg;i<end;i++)  matches[i-beg] = i;
 158         TABLESWITCH ts = new TABLESWITCH(matches,new InstructionHandle[matches.length],null);
 159         a(ts);
 160         for(int n=beg;n<end;n++){
 161             InstructionHandle h = a(fac.createInvoke(fullClassName,"run_"+toHex(n<<methodShift),Type.VOID,Type.NO_ARGS,INVOKESPECIAL));
 162             a(InstructionFactory.createBranchInstruction(GOTO,start));
 163             ts.setTarget(n-beg,h);
 164         }
 165
 166         ts.setTarget(a(InstructionConstants.POP)); // default case
 167         a(fac.createNew("org.ibex.nestedvm.Runtime$ExecutionException"));
 168         a(InstructionConstants.DUP);
 169         a(fac.createNew("java.lang.StringBuffer"));
 170         a(InstructionConstants.DUP);
 171         a(new PUSH(cp,"Jumped to invalid address in trampoline (r2: "));
 172         a(fac.createInvoke("java.lang.StringBuffer","<init>",Type.VOID,new Type[]{Type.STRING},INVOKESPECIAL));
 173         a(InstructionConstants.ALOAD_0);
 174         a(fac.createFieldAccess(fullClassName,"r2",Type.INT, GETFIELD));
 175         a(fac.createInvoke("java.lang.StringBuffer","append",Type.STRINGBUFFER,new Type[]{Type.INT},INVOKEVIRTUAL));
 176         a(new PUSH(cp," pc:"));
 177         a(fac.createInvoke("java.lang.StringBuffer","append",Type.STRINGBUFFER,new Type[]{Type.STRING},INVOKEVIRTUAL));
 178         a(InstructionConstants.ALOAD_0);
 179         a(fac.createFieldAccess(fullClassName,"pc",Type.INT, GETFIELD));
 180         a(fac.createInvoke("java.lang.StringBuffer","append",Type.STRINGBUFFER,new Type[]{Type.INT},INVOKEVIRTUAL));
 181         a(new PUSH(cp,')'));
 182         a(fac.createInvoke("java.lang.StringBuffer","append",Type.STRINGBUFFER,new Type[]{Type.CHAR},INVOKEVIRTUAL));
 183         a(fac.createInvoke("java.lang.StringBuffer","toString",Type.STRING,Type.NO_ARGS,INVOKEVIRTUAL));
 184         a(fac.createInvoke("org.ibex.nestedvm.Runtime$ExecutionException","<init>",Type.VOID,new Type[]{Type.STRING},INVOKESPECIAL));
 185         a(InstructionConstants.ATHROW);
 186
 187         stateCheck.setTarget(a(InstructionConstants.RETURN));
 188
 189         tramp.setMaxStack();
 190         tramp.setMaxLocals();
 191         try {
 192             cl.addMethod(tramp.getMethod());
 193         } catch(ClassGenException e) {
 194             e.printStackTrace(warn);
 195             throw new Exn("Generation of the trampoline method failed. Try increasing maxInsnPerMethod");
 196         }
 197
 198         addConstReturnMethod("gp",gp.addr);
 199         addConstReturnMethod("entryPoint",elf.header.entry);
 200         addConstReturnMethod("heapStart",highestAddr);
 201
 202         if(userInfo != null) {
 203             addConstReturnMethod("userInfoBase",userInfo.addr);
 204             addConstReturnMethod("userInfoSize",userInfo.size);
 205         }
 206
 207         // FEATURE: Allow specification of memory size at runtime (numpages)
 208         // Constructor
 209         MethodGen init = newMethod(ACC_PUBLIC,Type.VOID, Type.NO_ARGS, "<init>");
 210         selectMethod(init);
 211         a(InstructionConstants.ALOAD_0);
 212         pushConst(pageSize);
 213         pushConst(totalPages);
 214         a(fac.createInvoke(runtimeClass,"<init>",Type.VOID,new Type[]{Type.INT,Type.INT},INVOKESPECIAL));
 215
 216         a(initExtras);
 217
 218         a(InstructionConstants.RETURN);
 219
 220         init.setMaxLocals();
 221         init.setMaxStack();
 222         cl.addMethod(init.getMethod());
 223
 224
 225         MethodGen clinit = newMethod(ACC_PRIVATE|ACC_STATIC,Type.VOID, Type.NO_ARGS, "<clinit>");
 226         selectMethod(clinit);
 227         a(clinitExtras);
 228
 229         if(supportCall) {
 230             a(fac.createNew(hashClass));
 231             a(InstructionConstants.DUP);
 232             a(InstructionConstants.DUP);
 233             a(fac.createInvoke(hashClass,"<init>",Type.VOID,Type.NO_ARGS,INVOKESPECIAL));
 234             a(fac.createFieldAccess(fullClassName,"symbols",Type.getType("L"+hashClass.replace('.','/')+";"), PUTSTATIC));
 235             ELF.Symbol[] symbols = elf.getSymtab().symbols;
 236             for(int i=0;i<symbols.length;i++) {
 237                 ELF.Symbol s = symbols[i];
 238                 if(s.type == ELF.Symbol.STT_FUNC && s.binding == ELF.Symbol.STB_GLOBAL && (s.name.equals("_call_helper") || !s.name.startsWith("_"))) {
 239                     a(InstructionConstants.DUP);
 240                     a(new PUSH(cp,s.name));
 241                     a(fac.createNew("java.lang.Integer"));
 242                     a(InstructionConstants.DUP);
 243                     a(new PUSH(cp,s.addr));
 244                     a(fac.createInvoke("java.lang.Integer","<init>",Type.VOID,new Type[]{Type.INT},INVOKESPECIAL));
 245                     a(fac.createInvoke(hashClass,"put",Type.OBJECT,new Type[]{Type.OBJECT,Type.OBJECT},INVOKEVIRTUAL));
 246                     a(InstructionConstants.POP);
 247                 }
 248             }
 249             a(InstructionConstants.POP);
 250         }
 251
 252         a(InstructionConstants.RETURN);
 253         clinit.setMaxLocals();
 254         clinit.setMaxStack();
 255         cl.addMethod(clinit.getMethod());
 256
 257         if(supportCall) {
 258             MethodGen lookupSymbol = newMethod(ACC_PROTECTED,Type.INT,new Type[]{Type.STRING},"lookupSymbol");
 259             selectMethod(lookupSymbol);
 260             a(fac.createFieldAccess(fullClassName,"symbols",Type.getType("L"+hashClass.replace('.','/')+";"), GETSTATIC));
 261             a(InstructionConstants.ALOAD_1);
 262             a(fac.createInvoke(hashClass,"get",Type.OBJECT,new Type[]{Type.OBJECT},INVOKEVIRTUAL));
 263             a(InstructionConstants.DUP);
 264             BranchHandle bh = a(InstructionFactory.createBranchInstruction(IFNULL,null));
 265             a(fac.createCheckCast(new ObjectType("java.lang.Integer")));
 266             a(fac.createInvoke("java.lang.Integer","intValue",Type.INT,Type.NO_ARGS,INVOKEVIRTUAL));
 267             a(InstructionConstants.IRETURN);
 268             bh.setTarget(a(InstructionConstants.POP));
 269             a(InstructionConstants.ICONST_M1);
 270             a(InstructionConstants.IRETURN);
 271             lookupSymbol.setMaxLocals();
 272             lookupSymbol.setMaxStack();
 273             cl.addMethod(lookupSymbol.getMethod());
 274         }
 275
 276         MethodGen setCPUState = newMethod(ACC_PROTECTED,Type.VOID,new Type[]{Type.getType("Lorg/ibex/nestedvm/Runtime$CPUState;")},"setCPUState");
 277         selectMethod(setCPUState);
 278         a(InstructionConstants.ALOAD_1);
 279         a(fac.createFieldAccess("org.ibex.nestedvm.Runtime$CPUState","r",new ArrayType(Type.INT,1),GETFIELD));
 280         a(InstructionConstants.ASTORE_2);
 281         for(int i=1;i<32;i++) {
 282             a(InstructionConstants.ALOAD_0);
 283             a(InstructionConstants.ALOAD_2);
 284             pushConst(i);
 285             a(InstructionConstants.IALOAD);
 286             a(fac.createFieldAccess(fullClassName,"r"+i,Type.INT, PUTFIELD));
 287         }
 288         a(InstructionConstants.ALOAD_1);
 289         a(fac.createFieldAccess("org.ibex.nestedvm.Runtime$CPUState","f",new ArrayType(Type.INT,1),GETFIELD));
 290         a(InstructionConstants.ASTORE_2);
 291         for(int i=0;i<32;i++) {
 292             a(InstructionConstants.ALOAD_0);
 293             a(InstructionConstants.ALOAD_2);
 294             pushConst(i);
 295             a(InstructionConstants.IALOAD);
 296             a(fac.createFieldAccess(fullClassName,"f"+i,Type.INT, PUTFIELD));
 297         }
 298         a(InstructionConstants.ALOAD_0);
 299         a(InstructionConstants.ALOAD_1);
 300         a(fac.createFieldAccess("org.ibex.nestedvm.Runtime$CPUState","hi",Type.INT,GETFIELD));
 301         a(fac.createFieldAccess(fullClassName,"hi",Type.INT, PUTFIELD));
 302         a(InstructionConstants.ALOAD_0);
 303         a(InstructionConstants.ALOAD_1);
 304         a(fac.createFieldAccess("org.ibex.nestedvm.Runtime$CPUState","lo",Type.INT,GETFIELD));
 305         a(fac.createFieldAccess(fullClassName,"lo",Type.INT, PUTFIELD));
 306         a(InstructionConstants.ALOAD_0);
 307         a(InstructionConstants.ALOAD_1);
 308         a(fac.createFieldAccess("org.ibex.nestedvm.Runtime$CPUState","fcsr",Type.INT,GETFIELD));
 309         a(fac.createFieldAccess(fullClassName,"fcsr",Type.INT, PUTFIELD));
 310         a(InstructionConstants.ALOAD_0);
 311         a(InstructionConstants.ALOAD_1);
 312         a(fac.createFieldAccess("org.ibex.nestedvm.Runtime$CPUState","pc",Type.INT,GETFIELD));
 313         a(fac.createFieldAccess(fullClassName,"pc",Type.INT, PUTFIELD));
 314
 315         a(InstructionConstants.RETURN);
 316         setCPUState.setMaxLocals();
 317         setCPUState.setMaxStack();
 318         cl.addMethod(setCPUState.getMethod());
 319
 320         MethodGen getCPUState = newMethod(ACC_PROTECTED,Type.VOID,new Type[]{Type.getType("Lorg/ibex/nestedvm/Runtime$CPUState;")},"getCPUState");
 321         selectMethod(getCPUState);
 322         a(InstructionConstants.ALOAD_1);
 323         a(fac.createFieldAccess("org.ibex.nestedvm.Runtime$CPUState","r",new ArrayType(Type.INT,1),GETFIELD));
 324         a(InstructionConstants.ASTORE_2);
 325         for(int i=1;i<32;i++) {
 326             a(InstructionConstants.ALOAD_2);
 327             pushConst(i);
 328             a(InstructionConstants.ALOAD_0);
 329             a(fac.createFieldAccess(fullClassName,"r"+i,Type.INT, GETFIELD));
 330             a(InstructionConstants.IASTORE);
 331         }
 332
 333         a(InstructionConstants.ALOAD_1);
 334         a(fac.createFieldAccess("org.ibex.nestedvm.Runtime$CPUState","f",new ArrayType(Type.INT,1),GETFIELD));
 335         a(InstructionConstants.ASTORE_2);
 336         for(int i=0;i<32;i++) {
 337             a(InstructionConstants.ALOAD_2);
 338             pushConst(i);
 339             a(InstructionConstants.ALOAD_0);
 340             a(fac.createFieldAccess(fullClassName,"f"+i,Type.INT, GETFIELD));
 341             a(InstructionConstants.IASTORE);
 342         }
 343         a(InstructionConstants.ALOAD_1);
 344         a(InstructionConstants.ALOAD_0);
 345         a(fac.createFieldAccess(fullClassName,"hi",Type.INT, GETFIELD));
 346         a(fac.createFieldAccess("org.ibex.nestedvm.Runtime$CPUState","hi",Type.INT,PUTFIELD));
 347         a(InstructionConstants.ALOAD_1);
 348         a(InstructionConstants.ALOAD_0);
 349         a(fac.createFieldAccess(fullClassName,"lo",Type.INT, GETFIELD));
 350         a(fac.createFieldAccess("org.ibex.nestedvm.Runtime$CPUState","lo",Type.INT,PUTFIELD));
 351         a(InstructionConstants.ALOAD_1);
 352         a(InstructionConstants.ALOAD_0);
 353         a(fac.createFieldAccess(fullClassName,"fcsr",Type.INT, GETFIELD));
 354         a(fac.createFieldAccess("org.ibex.nestedvm.Runtime$CPUState","fcsr",Type.INT,PUTFIELD));
 355         a(InstructionConstants.ALOAD_1);
 356         a(InstructionConstants.ALOAD_0);
 357         a(fac.createFieldAccess(fullClassName,"pc",Type.INT, GETFIELD));
 358         a(fac.createFieldAccess("org.ibex.nestedvm.Runtime$CPUState","pc",Type.INT,PUTFIELD));
 359
 360         a(InstructionConstants.RETURN);
 361         getCPUState.setMaxLocals();
 362         getCPUState.setMaxStack();
 363         cl.addMethod(getCPUState.getMethod());
 364
 365
 366         MethodGen execute = newMethod(ACC_PROTECTED,Type.VOID,Type.NO_ARGS,"_execute");
 367         selectMethod(execute);
 368         InstructionHandle tryStart = a(InstructionConstants.ALOAD_0);
 369         InstructionHandle tryEnd = a(fac.createInvoke(fullClassName,"trampoline",Type.VOID,Type.NO_ARGS,INVOKESPECIAL));
 370         a(InstructionConstants.RETURN);
 371
 372         InstructionHandle catchInsn = a(InstructionConstants.ASTORE_1);
 373         a(fac.createNew("org.ibex.nestedvm.Runtime$FaultException"));
 374         a(InstructionConstants.DUP);
 375         a(InstructionConstants.ALOAD_1);
 376         a(fac.createInvoke("org.ibex.nestedvm.Runtime$FaultException","<init>",Type.VOID,new Type[]{new ObjectType("java.lang.RuntimeException")},INVOKESPECIAL));
 377         a(InstructionConstants.ATHROW);
 378
 379         execute.addExceptionHandler(tryStart,tryEnd,catchInsn,new ObjectType("java.lang.RuntimeException"));
 380         execute.setMaxLocals();
 381         execute.setMaxStack();
 382         cl.addMethod(execute.getMethod());
 383
 384
 385         MethodGen main = newMethod(ACC_STATIC|ACC_PUBLIC,Type.VOID,new Type[]{new ArrayType(Type.STRING,1)},"main");
 386         selectMethod(main);
 387         a(fac.createNew(fullClassName));
 388         a(InstructionConstants.DUP);
 389         a(fac.createInvoke(fullClassName,"<init>",Type.VOID,Type.NO_ARGS,INVOKESPECIAL));
 390         a(new PUSH(cp,fullClassName));
 391         a(InstructionConstants.ALOAD_0);
 392         if(unixRuntime)
 393             a(fac.createInvoke("org.ibex.nestedvm.UnixRuntime","runAndExec",Type.INT,
 394                 new Type[]{Type.getType("Lorg/ibex/nestedvm/UnixRuntime;"),Type.STRING,new ArrayType(Type.STRING,1)},
 395                 INVOKESTATIC));
 396         else
 397             a(fac.createInvoke(fullClassName,"run",Type.INT,new Type[]{Type.STRING,new ArrayType(Type.STRING,1)},INVOKEVIRTUAL));
 398         a(fac.createInvoke("java.lang.System","exit",Type.VOID,new Type[]{Type.INT},INVOKESTATIC));
 399         a(InstructionConstants.RETURN);
 400         main.setMaxLocals();
 401         main.setMaxStack();
 402         cl.addMethod(main.getMethod());
 403
 404         if(printStats)
 405             System.out.println("Constant Pool Size: " + cp.getSize());
 406         cl.getJavaClass().dump(os);
 407     }
 408
 409     private void addConstReturnMethod(String name, int val) {
 410         MethodGen method = newMethod(ACC_PROTECTED,Type.INT, Type.NO_ARGS,name);
 411         selectMethod(method);
 412         pushConst(val);
 413         a(InstructionConstants.IRETURN);
 414         method.setMaxLocals();
 415         method.setMaxStack();
 416         cl.addMethod(method.getMethod());
 417     }
 418
 419     private static int initDataCount;
 420     private void emitData(int addr, DataInputStream dis, int size, boolean readOnly) throws Exn,IOException {
 421         if((addr&3)!=0 || (size&3)!=0) throw new Exn("Data section on weird boundaries");
 422         int last = addr + size;
 423         while(addr < last) {
 424             int segSize = Math.min(size,28000); // must be a multiple of 56
 425             StringBuffer sb = new StringBuffer();
 426             for(int i=0;i<segSize;i+=7) {
 427                 long l = 0;
 428                 for(int j=0;j<7;j++) {
 429                     l <<= 8;
 430                     byte b = (i+j < size) ? dis.readByte() : 1;
 431                     l |= (b & 0xffL);
 432                 }
 433                 for(int j=0;j<8;j++)
 434                     sb.append((char) ((l>>>(7*(7-j)))&0x7f));
 435             }
 436             String fieldname =  "_data" + (++initDataCount);
 437             cl.addField(new FieldGen(ACC_PRIVATE|ACC_STATIC|ACC_FINAL,new ArrayType(Type.INT,1),fieldname,cp).getField());
 438
 439             selectList(clinitExtras);
 440             a(new PUSH(cp,sb.toString()));
 441             a(new PUSH(cp,segSize/4));
 442             a(fac.createInvoke("org.ibex.nestedvm.Runtime","decodeData",new ArrayType(Type.INT,1),new Type[]{Type.STRING,Type.INT},INVOKESTATIC));
 443             a(fac.createPutStatic(fullClassName,fieldname,new ArrayType(Type.INT,1)));
 444
 445             selectList(initExtras);
 446             a(InstructionConstants.ALOAD_0);
 447             a(fac.createGetStatic(fullClassName,fieldname,new ArrayType(Type.INT,1)));
 448             a(new PUSH(cp,addr));
 449             a(new PUSH(cp,readOnly));
 450             a(fac.createInvoke(fullClassName,"initPages",Type.VOID,new Type[]{new ArrayType(Type.INT,1),Type.INT,Type.BOOLEAN},INVOKEVIRTUAL));
 451
 452             addr += segSize;
 453             size -= segSize;
 454         }
 455         dis.close();
 456     }
 457
 458     private void emitBSS(int addr, int size) throws Exn {
 459         if((addr&3)!=0) throw new Exn("BSS section on weird boundaries");
 460         size = (size+3)&~3;
 461         int count = size/4;
 462         selectList(initExtras);
 463         a(InstructionConstants.ALOAD_0);
 464         a(new PUSH(cp,addr));
 465         a(new PUSH(cp,count));
 466         a(fac.createInvoke(fullClassName,"clearPages",Type.VOID,new Type[]{Type.INT,Type.INT},INVOKEVIRTUAL));
 467     }
 468
 469     // method state info
 470     private boolean textDone;
 471     private int startOfMethod = 0;
 472     private int endOfMethod = 0;
 473     private boolean unreachable = false;
 474     private InstructionHandle[] jumpHandles;
 475     private InstructionHandle defaultHandle;
 476     private InstructionHandle returnHandle;
 477     private InstructionHandle realStart;
 478     private MethodGen curMethod;
 479
 480     private boolean jumpable(int addr) { return jumpableAddresses.get(new Integer(addr)) != null; }
 481
 482     private void emitText(int addr, DataInputStream dis, int size) throws Exn,IOException {
 483         if(textDone) throw new Exn("Multiple text segments");
 484         textDone = true;
 485
 486         if((addr&3)!=0 || (size&3)!=0) throw new Exn("Section on weird boundaries");
 487         int count = size/4;
 488         int insn,nextInsn=-1;
 489         boolean skipNext = true;
 490
 491         for(int i=0;i<count;i++,addr+=4) {
 492             insn = skipNext ? dis.readInt() : nextInsn;
 493             nextInsn = (i == count-1) ? -1 : dis.readInt();
 494             if(addr >= endOfMethod) { endMethod(addr); startMethod(addr); }
 495             if(jumpHandles[(addr-startOfMethod)/4] != null) {
 496                 // Move the fake jump target to the current location
 497                 insnList.move(jumpHandles[(addr-startOfMethod)/4],insnList.getEnd());
 498                 unreachable = false;
 499             } else if(unreachable) {
 500                 continue;
 501             }
 502             try {
 503                 skipNext = emitInstruction(addr,insn,nextInsn);
 504             } catch(RuntimeException e) {
 505                 warn.println("Exception at " + toHex(addr));
 506                 throw e;
 507             }
 508             if(skipNext) { addr+=4; i++; }
 509         }
 510         endMethod(0);
 511         dis.close();
 512     }
 513
 514     private void startMethod(int first) {
 515         startOfMethod = first & methodMask;
 516         endOfMethod = startOfMethod + maxBytesPerMethod;
 517         curMethod = newMethod(ACC_PRIVATE,Type.VOID,Type.NO_ARGS,"run_" + toHex(startOfMethod));
 518         selectMethod(curMethod);
 519
 520         int[] buf = new int[maxBytesPerMethod/4];
 521         jumpHandles = new InstructionHandle[maxBytesPerMethod/4];
 522         int n=0;
 523         for(int addr=first;addr<endOfMethod;addr+=4) {
 524             if(jumpable(addr)) {
 525                 buf[n++] = addr;
 526                 // append NOPs for GOTO jumps (these will be moved to the correct location later)
 527                 jumpHandles[(addr-startOfMethod)/4] = a(InstructionConstants.NOP);
 528             }
 529         }
 530
 531         // append NOP for default case (throw exn) (this will be moved later)
 532         defaultHandle = a(InstructionConstants.NOP);
 533         returnHandle = a(InstructionConstants.NOP);
 534
 535         int[] matches = new int[n];
 536         System.arraycopy(buf,0,matches,0,n);
 537         InstructionHandle[] targets = new InstructionHandle[n];
 538         for(int i=0;i<matches.length;i++)
 539             targets[i] = jumpHandles[(matches[i]-startOfMethod)/4];
 540
 541
 542         // First instruction of the actual method - everything above this should be removed
 543         // before we get to the end
 544         realStart = a(InstructionConstants.NOP);
 545
 546         if(onePage) {
 547             a(InstructionConstants.ALOAD_0);
 548             a(fac.createFieldAccess(fullClassName,"page",new ArrayType(Type.INT,1), GETFIELD));
 549             a(InstructionConstants.ASTORE_2);
 550         } else {
 551             a(InstructionConstants.ALOAD_0);
 552             a(fac.createFieldAccess(fullClassName,"readPages",new ArrayType(Type.INT,2), GETFIELD));
 553             a(InstructionConstants.ASTORE_2);
 554             a(InstructionConstants.ALOAD_0);
 555             a(fac.createFieldAccess(fullClassName,"writePages",new ArrayType(Type.INT,2), GETFIELD));
 556             a(InstructionFactory.createStore(Type.OBJECT,3));
 557         }
 558
 559         LOOKUPSWITCH initialSwitch = new LOOKUPSWITCH(matches,targets,defaultHandle);
 560         a(InstructionConstants.ALOAD_0);
 561         a(fac.createFieldAccess(fullClassName,"pc",Type.INT, GETFIELD));
 562         a(initialSwitch);
 563     }
 564
 565     private void endMethod(int firstAddrOfNext) {
 566         if(startOfMethod == 0) return;
 567
 568         if(!unreachable) {
 569             preSetPC();
 570             pushConst(firstAddrOfNext);
 571             setPC();
 572             // mark the start of the next method as jumpable
 573             jumpableAddresses.put(new Integer(firstAddrOfNext),Boolean.TRUE);
 574         }
 575
 576         insnList.move(returnHandle,insnList.getEnd());
 577         fixupRegs();
 578         a(InstructionConstants.RETURN);
 579
 580         // move the default jump target (lookupswitch) to before the throw
 581         insnList.move(defaultHandle,insnList.getEnd());
 582         if(debugCompiler) {
 583             a(fac.createNew("org.ibex.nestedvm.Runtime$ExecutionException"));
 584             a(InstructionConstants.DUP);
 585             a(fac.createNew("java.lang.StringBuffer"));
 586             a(InstructionConstants.DUP);
 587             a(new PUSH(cp,"Jumped to invalid address: "));
 588             a(fac.createInvoke("java.lang.StringBuffer","<init>",Type.VOID,new Type[]{Type.STRING},INVOKESPECIAL));
 589             a(InstructionConstants.ALOAD_0);
 590             a(fac.createFieldAccess(fullClassName,"pc",Type.INT, GETFIELD));
 591             a(fac.createInvoke("java.lang.StringBuffer","append",Type.STRINGBUFFER,new Type[]{Type.INT},INVOKEVIRTUAL));
 592             a(fac.createInvoke("java.lang.StringBuffer","toString",Type.STRING,Type.NO_ARGS,INVOKEVIRTUAL));
 593             a(fac.createInvoke("org.ibex.nestedvm.Runtime$ExecutionException","<init>",Type.VOID,new Type[]{Type.STRING},INVOKESPECIAL));
 594             a(InstructionConstants.ATHROW);
 595         } else {
 596             a(fac.createNew("org.ibex.nestedvm.Runtime$ExecutionException"));
 597             a(InstructionConstants.DUP);
 598             a(new PUSH(cp,"Jumped to invalid address"));
 599             a(fac.createInvoke("org.ibex.nestedvm.Runtime$ExecutionException","<init>",Type.VOID,new Type[]{Type.STRING},INVOKESPECIAL));
 600             a(InstructionConstants.ATHROW);
 601         }
 602
 603         if(insnList.getStart() != realStart) {
 604             System.err.println(insnList);
 605             throw new Error("A jumpHandle wasn't moved into place");
 606         }
 607
 608         curMethod.removeNOPs();
 609         curMethod.setMaxLocals();
 610         curMethod.setMaxStack();
 611
 612         cl.addMethod(curMethod.getMethod());
 613
 614         endOfMethod = startOfMethod = 0;
 615     }
 616
 617
 618     private void leaveMethod() {
 619         a(InstructionFactory.createBranchInstruction(GOTO,returnHandle));
 620     }
 621
 622     private void branch(int pc, int target) {
 623         if((pc&methodMask) == (target&methodMask)) {
 624             a(InstructionFactory.createBranchInstruction(GOTO,jumpHandles[(target-startOfMethod)/4]));
 625         } else {
 626             preSetPC();
 627             pushConst(target);
 628             setPC();
 629             leaveMethod();
 630         }
 631     }
 632
 633     // This assumes everything needed by ifInsn is already on the stack
 634     private boolean doIfInstruction(short op, int pc, int target, int nextInsn) throws Exn {
 635         emitInstruction(-1,nextInsn,-1); // delay slot
 636         BranchHandle h;
 637         IfInstruction ifInsn = (IfInstruction) InstructionFactory.createBranchInstruction(op,null);
 638         if((target&methodMask) == (pc&methodMask)) {
 639             h = a(ifInsn);
 640             h.setTarget(jumpHandles[(target-startOfMethod)/4]);
 641         } else {
 642             h = a(ifInsn.negate());
 643             branch(pc,target);
 644             h.setTarget(a(InstructionConstants.NOP));
 645         }
 646         if(!jumpable(pc+4)) return true; // done - skip it
 647
 648         //System.err.println("Delay slot is jumpable - This code is untested + " + toHex(nextInsn));
 649         if(pc+4==endOfMethod) {
 650             // the delay slot is at the start of the next method
 651             jumpableAddresses.put(new Integer(pc+8),Boolean.TRUE); // make the 2nd insn of the next method jumpable
 652             branch(pc,pc+8); // jump over it
 653             //System.err.println("delay slot: " + toHex(pc+8));
 654             unreachable = true;
 655             return false; // we still need to output it
 656         } else {
 657             //System.err.println("jumped over delay slot: " + toHex(pc+4));
 658             // add another copy and jump over
 659             h = a(InstructionFactory.createBranchInstruction(GOTO,null));
 660             insnList.move(jumpHandles[(pc+4-startOfMethod)/4],insnList.getEnd());
 661             emitInstruction(-1,nextInsn,-1); // delay slot
 662             h.setTarget(a(InstructionConstants.NOP));
 663             return true;
 664         }
 665     }
 666
 667     private boolean emitInstruction(int pc, int insn, int nextInsn) throws Exn {
 668         if(insn == -1) throw new Exn("insn is -1");
 669
 670         int op = (insn >>> 26) & 0xff;                 // bits 26-31
 671         int rs = (insn >>> 21) & 0x1f;                 // bits 21-25
 672         int rt = (insn >>> 16) & 0x1f;                 // bits 16-20
 673         int ft = (insn >>> 16) & 0x1f;
 674         int rd = (insn >>> 11) & 0x1f;                 // bits 11-15
 675         int fs = (insn >>> 11) & 0x1f;
 676         int shamt = (insn >>> 6) & 0x1f;               // bits 6-10
 677         int fd = (insn >>> 6) & 0x1f;
 678         int subcode = insn & 0x3f;                     // bits 0-5
 679         int breakCode = (insn >>> 6) & 0xfffff;         // bits 6-20
 680
 681         int jumpTarget = (insn & 0x03ffffff);          // bits 0-25
 682         int unsignedImmediate = insn & 0xffff;
 683         int signedImmediate = (insn << 16) >> 16;
 684         int branchTarget = signedImmediate;
 685
 686         // temporaries
 687         BranchHandle b1,b2;
 688
 689         switch(op) {
 690         case 0: {
 691             switch(subcode) {
 692             case 0: // SLL
 693                 if(insn == 0) break;
 694                 preSetReg(R+rd);
 695                 pushRegWZ(R+rt);
 696                 pushConst(shamt);
 697                 a(InstructionConstants.ISHL);
 698                 setReg();
 699                 break;
 700             case 2: // SRL
 701                 preSetReg(R+rd);
 702                 pushRegWZ(R+rt);
 703                 pushConst(shamt);
 704                 a(InstructionConstants.IUSHR);
 705                 setReg();
 706                 break;
 707             case 3: // SRA
 708                 preSetReg(R+rd);
 709                 pushRegWZ(R+rt);
 710                 pushConst(shamt);
 711                 a(InstructionConstants.ISHR);
 712                 setReg();
 713                 break;
 714             case 4: // SLLV
 715                 preSetReg(R+rd);
 716                 pushRegWZ(R+rt);
 717                 pushRegWZ(R+rs);
 718                 a(InstructionConstants.ISHL);
 719                 setReg();
 720                 break;
 721             case 6: // SRLV
 722                 preSetReg(R+rd);
 723                 pushRegWZ(R+rt);
 724                 pushRegWZ(R+rs);
 725                 a(InstructionConstants.IUSHR);
 726                 setReg();
 727                 break;
 728             case 7: // SRAV
 729                 preSetReg(R+rd);
 730                 pushRegWZ(R+rt);
 731                 pushRegWZ(R+rs);
 732                 a(InstructionConstants.ISHR);
 733                 setReg();
 734                 break;
 735             case 8: // JR
 736                 if(pc == -1) throw new Exn("pc modifying insn in delay slot");
 737                 emitInstruction(-1,nextInsn,-1);
 738                 preSetPC();
 739                 pushRegWZ(R+rs);
 740                 setPC();
 741                 leaveMethod();
 742                 unreachable = true;
 743                 break;
 744             case 9: // JALR
 745                 if(pc == -1) throw new Exn("pc modifying insn in delay slot");
 746                 emitInstruction(-1,nextInsn,-1);
 747                 preSetPC();
 748                 pushRegWZ(R+rs);
 749                 setPC();
 750
 751                 preSetReg(R+RA);
 752                 pushConst(pc+8);
 753                 setReg();
 754                 leaveMethod();
 755                 unreachable = true;
 756                 break;
 757             case 12: // SYSCALL
 758                 preSetPC();
 759                 pushConst(pc);
 760                 setPC();
 761
 762                 restoreChangedRegs();
 763
 764                 preSetReg(R+V0);
 765                 a(InstructionConstants.ALOAD_0);
 766                 pushRegZ(R+V0);
 767                 pushRegZ(R+A0);
 768                 pushRegZ(R+A1);
 769                 pushRegZ(R+A2);
 770                 pushRegZ(R+A3);
 771                 pushRegZ(R+T0);
 772                 pushRegZ(R+T1);
 773                 a(fac.createInvoke(fullClassName,"syscall",Type.INT,new Type[]{Type.INT,Type.INT,Type.INT,Type.INT,Type.INT,Type.INT,Type.INT},INVOKEVIRTUAL));
 774                 setReg();
 775
 776                 a(InstructionConstants.ALOAD_0);
 777                 a(fac.createFieldAccess(fullClassName,"state",Type.INT, GETFIELD));
 778                 pushConst(Runtime.RUNNING);
 779                 b1 = a(InstructionFactory.createBranchInstruction(IF_ICMPEQ,null));
 780                 preSetPC();
 781                 pushConst(pc+4);
 782                 setPC();
 783                 leaveMethod();
 784                 b1.setTarget(a(InstructionConstants.NOP));
 785
 786                 break;
 787             case 13: // BREAK
 788                 a(fac.createNew("org.ibex.nestedvm.Runtime$ExecutionException"));
 789                 a(InstructionConstants.DUP);
 790                 a(new PUSH(cp,"BREAK Code " + toHex(breakCode)));
 791                 a(fac.createInvoke("org.ibex.nestedvm.Runtime$ExecutionException","<init>",Type.VOID,new Type[]{Type.STRING},INVOKESPECIAL));
 792                 a(InstructionConstants.ATHROW);
 793                 unreachable = true;
 794                 break;
 795             case 16: // MFHI
 796                 preSetReg(R+rd);
 797                 pushReg(HI);
 798                 setReg();
 799                 break;
 800             case 17: // MTHI
 801                 preSetReg(HI);
 802                 pushRegZ(R+rs);
 803                 setReg();
 804                 break;
 805             case 18: // MFLO
 806                 preSetReg(R+rd);
 807                 pushReg(LO);
 808                 setReg();
 809                 break;
 810             case 19: // MTLO
 811                 preSetReg(LO);
 812                 pushRegZ(R+rs);
 813                 setReg();
 814                 break;
 815             case 24: // MULT
 816                 pushRegWZ(R+rs);
 817                 a(InstructionConstants.I2L);
 818                 pushRegWZ(R+rt);
 819                 a(InstructionConstants.I2L);
 820                 a(InstructionConstants.LMUL);
 821                 a(InstructionConstants.DUP2);
 822
 823                 a(InstructionConstants.L2I);
 824                 if(preSetReg(LO))
 825                     a(InstructionConstants.SWAP);
 826                 setReg();
 827
 828                 pushConst(32);
 829                 a(InstructionConstants.LUSHR);
 830                 a(InstructionConstants.L2I);
 831                 if(preSetReg(HI))
 832                     a(InstructionConstants.SWAP);
 833                 setReg();
 834
 835                 break;
 836             case 25: // MULTU
 837                 pushRegWZ(R+rs);
 838                 a(InstructionConstants.I2L);
 839                 pushConst(0xffffffffL);
 840                 a(InstructionConstants.LAND);
 841                 pushRegWZ(R+rt);
 842                 a(InstructionConstants.I2L);
 843                 pushConst(0xffffffffL);
 844                 a(InstructionConstants.LAND);
 845                 a(InstructionConstants.LMUL);
 846                 a(InstructionConstants.DUP2);
 847
 848                 a(InstructionConstants.L2I);
 849                 if(preSetReg(LO))
 850                     a(InstructionConstants.SWAP);
 851                 setReg();
 852
 853                 pushConst(32);
 854                 a(InstructionConstants.LUSHR);
 855                 a(InstructionConstants.L2I);
 856                 if(preSetReg(HI))
 857                     a(InstructionConstants.SWAP);
 858                 setReg();
 859
 860                 break;
 861             case 26: // DIV
 862                 pushRegWZ(R+rs);
 863                 pushRegWZ(R+rt);
 864                 a(InstructionConstants.DUP2);
 865
 866                 a(InstructionConstants.IDIV);
 867                 if(preSetReg(LO))
 868                     a(InstructionConstants.SWAP);
 869                 setReg();
 870
 871                 a(InstructionConstants.IREM);
 872                 if(preSetReg(HI))
 873                     a(InstructionConstants.SWAP);
 874                 setReg();
 875
 876                 break;
 877             case 27: { // DIVU
 878                 pushRegWZ(R+rt);
 879                 a(InstructionConstants.DUP);
 880                 setTmp();
 881                 b1 = a(InstructionFactory.createBranchInstruction(IFEQ,null));
 882
 883                 pushRegWZ(R+rs);
 884                 a(InstructionConstants.I2L);
 885                 pushConst(0xffffffffL);
 886                 a(InstructionConstants.LAND);
 887                 a(InstructionConstants.DUP2);
 888                 pushTmp();
 889                 a(InstructionConstants.I2L);
 890                 pushConst(0xffffffffL);
 891
 892                 a(InstructionConstants.LAND);
 893                 a(InstructionConstants.DUP2_X2);
 894                 a(InstructionConstants.LDIV);
 895
 896                 a(InstructionConstants.L2I);
 897                 if(preSetReg(LO))
 898                     a(InstructionConstants.SWAP);
 899                 setReg();
 900
 901                 a(InstructionConstants.LREM);
 902                 a(InstructionConstants.L2I);
 903                 if(preSetReg(HI))
 904                     a(InstructionConstants.SWAP);
 905                 setReg();
 906
 907                 b1.setTarget(a(InstructionConstants.NOP));
 908
 909                 break;
 910             }
 911             case 32: // ADD
 912                 throw new Exn("ADD (add with oveflow trap) not suported");
 913             case 33: // ADDU
 914                 preSetReg(R+rd);
 915                 if(rt != 0 && rs != 0) {
 916                     pushReg(R+rs);
 917                     pushReg(R+rt);
 918                     a(InstructionConstants.IADD);
 919                 } else if(rs != 0) {
 920                     pushReg(R+rs);
 921                 } else {
 922                     pushRegZ(R+rt);
 923                 }
 924                 setReg();
 925                 break;
 926             case 34: // SUB
 927                 throw new Exn("SUB (add with oveflow trap) not suported");
 928             case 35: // SUBU
 929                 preSetReg(R+rd);
 930                 if(rt != 0 && rs != 0) {
 931                     pushReg(R+rs);
 932                     pushReg(R+rt);
 933                     a(InstructionConstants.ISUB);
 934                 } else if(rt != 0) {
 935                     pushReg(R+rt);
 936                     a(InstructionConstants.INEG);
 937                 } else {
 938                     pushRegZ(R+rs);
 939                 }
 940                 setReg();
 941                 break;
 942             case 36: // AND
 943                 preSetReg(R+rd);
 944                 pushRegWZ(R+rs);
 945                 pushRegWZ(R+rt);
 946                 a(InstructionConstants.IAND);
 947                 setReg();
 948                 break;
 949             case 37: // OR
 950                 preSetReg(R+rd);
 951                 pushRegWZ(R+rs);
 952                 pushRegWZ(R+rt);
 953                 a(InstructionConstants.IOR);
 954                 setReg();
 955                 break;
 956             case 38: // XOR
 957                 preSetReg(R+rd);
 958                 pushRegWZ(R+rs);
 959                 pushRegWZ(R+rt);
 960                 a(InstructionConstants.IXOR);
 961                 setReg();
 962                 break;
 963             case 39: // NOR
 964                 preSetReg(R+rd);
 965                 if(rs != 0 || rt != 0) {
 966                     if(rs != 0 && rt != 0) {
 967                         pushReg(R+rs);
 968                         pushReg(R+rt);
 969                         a(InstructionConstants.IOR);
 970                     } else if(rs != 0) {
 971                         pushReg(R+rs);
 972                     } else {
 973                         pushReg(R+rt);
 974                     }
 975                     a(InstructionConstants.ICONST_M1);
 976                     a(InstructionConstants.IXOR);
 977                 } else {
 978                     pushConst(-1);
 979                 }
 980                 setReg();
 981                 break;
 982             case 42: // SLT
 983                 preSetReg(R+rd);
 984                 if(rs != rt) {
 985                     pushRegZ(R+rs);
 986                     pushRegZ(R+rt);
 987                     b1 = a(InstructionFactory.createBranchInstruction(IF_ICMPLT,null));
 988                     a(InstructionConstants.ICONST_0);
 989                     b2 = a(InstructionFactory.createBranchInstruction(GOTO,null));
 990                     b1.setTarget(a(InstructionConstants.ICONST_1));
 991                     b2.setTarget(a(InstructionConstants.NOP));
 992                 } else {
 993                     pushConst(0);
 994                 }
 995                 setReg();
 996                 break;
 997             case 43: // SLTU
 998                 preSetReg(R+rd);
 999                 if(rs != rt) {
1000                     if(rs != 0) {
1001                         pushReg(R+rs);
1002                         a(InstructionConstants.I2L);
1003                         pushConst(0xffffffffL);
1004                         a(InstructionConstants.LAND);
1005                         pushReg(R+rt);
1006                         a(InstructionConstants.I2L);
1007                         pushConst(0xffffffffL);
1008                         a(InstructionConstants.LAND);
1009                         a(InstructionConstants.LCMP);
1010                         b1 = a(InstructionFactory.createBranchInstruction(IFLT,null));
1011                     } else {
1012                         pushReg(R+rt);
1013                         b1 = a(InstructionFactory.createBranchInstruction(IFNE,null));
1014                     }
1015                     a(InstructionConstants.ICONST_0);
1016                     b2 = a(InstructionFactory.createBranchInstruction(GOTO,null));
1017                     b1.setTarget(a(InstructionConstants.ICONST_1));
1018                     b2.setTarget(a(InstructionConstants.NOP));
1019                 } else {
1020                     pushConst(0);
1021                 }
1022                 setReg();
1023                 break;
1024             default:
1025                 throw new Exn("Illegal instruction 0/" + subcode);
1026             }
1027             break;
1028         }
1029         case 1: {
1030             switch(rt) {
1031             case 0: // BLTZ
1032                 if(pc == -1) throw new Exn("pc modifying insn in delay slot");
1033                 pushRegWZ(R+rs);
1034                 return doIfInstruction(IFLT,pc,pc+branchTarget*4+4,nextInsn);
1035             case 1: // BGEZ
1036                 if(pc == -1) throw new Exn("pc modifying insn in delay slot");
1037                 pushRegWZ(R+rs);
1038                 return doIfInstruction(IFGE,pc,pc+branchTarget*4+4,nextInsn);
1039             case 16: // BLTZAL
1040                 if(pc == -1) throw new Exn("pc modifying insn in delay slot");
1041                 pushRegWZ(R+rs);
1042                 b1 = a(InstructionFactory.createBranchInstruction(IFGE,null));
1043                 emitInstruction(-1,nextInsn,-1);
1044                 preSetReg(R+RA);
1045                 pushConst(pc+8);
1046                 setReg();
1047                 branch(pc,pc+branchTarget*4+4);
1048                 b1.setTarget(a(InstructionConstants.NOP));
1049                 break;
1050             case 17: // BGEZAL
1051                 if(pc == -1) throw new Exn("pc modifying insn in delay slot");
1052                 b1 = null;
1053                 if(rs != 0) { // r0 is always >= 0
1054                     pushRegWZ(R+rs);
1055                     b1 = a(InstructionFactory.createBranchInstruction(IFLT,null));
1056                 }
1057                 emitInstruction(-1,nextInsn,-1);
1058                 preSetReg(R+RA);
1059                 pushConst(pc+8);
1060                 setReg();
1061                 branch(pc,pc+branchTarget*4+4);
1062                 if(b1 != null) b1.setTarget(a(InstructionConstants.NOP));
1063                 if(b1 == null) unreachable = true;
1064                 break;
1065             default:
1066                 throw new Exn("Illegal Instruction 1/" + rt);
1067             }
1068             break;
1069         }
1070         case 2: { // J
1071             if(pc == -1) throw new Exn("pc modifying insn in delay slot");
1072             emitInstruction(-1,nextInsn,-1);
1073             branch(pc,(pc&0xf0000000)|(jumpTarget << 2));
1074             unreachable = true;
1075             break;
1076         }
1077         case 3: { // JAL
1078             if(pc == -1) throw new Exn("pc modifying insn in delay slot");
1079             int target = (pc&0xf0000000)|(jumpTarget << 2);
1080             emitInstruction(-1,nextInsn,-1);
1081             preSetReg(R+RA);
1082             pushConst(pc+8);
1083             setReg();
1084             branch(pc, target);
1085             unreachable = true;
1086             break;
1087         }
1088         case 4: // BEQ
1089             if(pc == -1) throw new Exn("pc modifying insn in delay slot");
1090             if(rs == rt) {
1091                 emitInstruction(-1,nextInsn,-1);
1092                 branch(pc,pc+branchTarget*4+4);
1093                 unreachable = true;
1094             } else if(rs == 0 || rt == 0) {
1095                 pushReg(rt == 0 ? R+rs : R+rt);
1096                 return doIfInstruction(IFEQ,pc,pc+branchTarget*4+4,nextInsn);
1097             } else {
1098                 pushReg(R+rs);
1099                 pushReg(R+rt);
1100                 return doIfInstruction(IF_ICMPEQ,pc,pc+branchTarget*4+4,nextInsn);
1101             }
1102             break;
1103         case 5: // BNE
1104             if(pc == -1) throw new Exn("pc modifying insn in delay slot");
1105             pushRegWZ(R+rs);
1106             if(rt == 0) {
1107                 return doIfInstruction(IFNE,pc,pc+branchTarget*4+4,nextInsn);
1108             } else {
1109                 pushReg(R+rt);
1110                 return doIfInstruction(IF_ICMPNE,pc,pc+branchTarget*4+4,nextInsn);
1111             }
1112         case 6: //BLEZ
1113             if(pc == -1) throw new Exn("pc modifying insn in delay slot");
1114             pushRegWZ(R+rs);
1115             return doIfInstruction(IFLE,pc,pc+branchTarget*4+4,nextInsn);
1116         case 7: //BGTZ
1117             if(pc == -1) throw new Exn("pc modifying insn in delay slot");
1118             pushRegWZ(R+rs);
1119             return doIfInstruction(IFGT,pc,pc+branchTarget*4+4,nextInsn);
1120         case 8: // ADDI
1121             throw new Exn("ADDI (add immediate with oveflow trap) not suported");
1122         case 9: // ADDIU
1123             preSetReg(R+rt);
1124             addiu(rs,signedImmediate);
1125             setReg();
1126             break;
1127         case 10: // SLTI
1128             preSetReg(R+rt);
1129             pushRegWZ(R+rs);
1130             pushConst(signedImmediate);
1131             b1 = a(InstructionFactory.createBranchInstruction(IF_ICMPLT,null));
1132             a(InstructionConstants.ICONST_0);
1133             b2 = a(InstructionFactory.createBranchInstruction(GOTO,null));
1134             b1.setTarget(a(InstructionConstants.ICONST_1));
1135             b2.setTarget(a(InstructionConstants.NOP));
1136             setReg();
1137             break;
1138         case 11: // SLTIU
1139             preSetReg(R+rt);
1140             pushRegWZ(R+rs);
1141             a(InstructionConstants.I2L);
1142             pushConst(0xffffffffL);
1143             a(InstructionConstants.LAND);
1144             // Yes, this is correct, you have to sign extend the immediate then do an UNSIGNED comparison
1145             pushConst(signedImmediate&0xffffffffL);
1146             a(InstructionConstants.LCMP);
1147
1148             b1 = a(InstructionFactory.createBranchInstruction(IFLT,null));
1149             a(InstructionConstants.ICONST_0);
1150             b2 = a(InstructionFactory.createBranchInstruction(GOTO,null));
1151             b1.setTarget(a(InstructionConstants.ICONST_1));
1152             b2.setTarget(a(InstructionConstants.NOP));
1153
1154             setReg();
1155             break;
1156         case 12: // ANDI
1157             preSetReg(R+rt);
1158             pushRegWZ(R+rs);
1159             pushConst(unsignedImmediate);
1160             a(InstructionConstants.IAND);
1161             setReg();
1162             break;
1163         case 13: // ORI
1164             preSetReg(R+rt);
1165             if(rs != 0 && unsignedImmediate != 0) {
1166                 pushReg(R+rs);
1167                 pushConst(unsignedImmediate);
1168                 a(InstructionConstants.IOR);
1169             } else if(rs != 0){
1170                 pushReg(R+rs);
1171             } else {
1172                 pushConst(unsignedImmediate);
1173             }
1174             setReg();
1175             break;
1176         case 14: // XORI
1177             preSetReg(R+rt);
1178             pushRegWZ(R+rs);
1179             pushConst(unsignedImmediate);
1180             a(InstructionConstants.IXOR);
1181             setReg();
1182             break;
1183         case 15: // LUI
1184             preSetReg(R+rt);
1185             pushConst(unsignedImmediate << 16);
1186             setReg();
1187             break;
1188         case 16:
1189             throw new Exn("TLB/Exception support not implemented");
1190         case 17: { // FPU
1191             switch(rs) {
1192             case 0: // MFC.1
1193                 preSetReg(R+rt);
1194                 pushReg(F+rd);
1195                 setReg();
1196                 break;
1197             case 2: // CFC.1
1198                 if(fs != 31) throw new Exn("FCR " + fs + " unavailable");
1199                 preSetReg(R+rt);
1200                 pushReg(FCSR);
1201                 setReg();
1202                 break;
1203             case 4: // MTC.1
1204                 preSetReg(F+rd);
1205                 if(rt != 0)
1206                     pushReg(R+rt);
1207                 else
1208                     pushConst(0);
1209                 setReg();
1210                 break;
1211             case 6: // CTC.1
1212                 if(fs != 31) throw new Exn("FCR " + fs + " unavailable");
1213                 preSetReg(FCSR);
1214                 pushReg(R+rt);
1215                 setReg();
1216                 break;
1217             case 8: {// BC1F, BC1T
1218                 pushReg(FCSR);
1219                 pushConst(0x800000);
1220                 a(InstructionConstants.IAND);
1221                 return doIfInstruction(((insn>>>16)&1) == 0 ? IFEQ : IFNE,pc,pc+branchTarget*4+4,nextInsn);
1222             }
1223             case 16:
1224             case 17:
1225             { // Single/Double math
1226                 boolean d = rs == 17;
1227                 switch(subcode) {
1228                 case 0: // ADD.X
1229                     preSetDouble(F+fd,d);
1230                     pushDouble(F+fs,d);
1231                     pushDouble(F+ft,d);
1232                     a(d ? InstructionConstants.DADD : InstructionConstants.FADD);
1233                     setDouble(d);
1234                     break;
1235                 case 1: // SUB.X
1236                     preSetDouble(F+fd,d);
1237                     pushDouble(F+fs,d);
1238                     pushDouble(F+ft,d);
1239                     a(d ? InstructionConstants.DSUB : InstructionConstants.FSUB);
1240                     setDouble(d);
1241                     break;
1242                 case 2: // MUL.X
1243                     preSetDouble(F+fd,d);
1244                     pushDouble(F+fs,d);
1245                     pushDouble(F+ft,d);
1246                     a(d ? InstructionConstants.DMUL : InstructionConstants.FMUL);
1247                     setDouble(d);
1248                     break;
1249                 case 3: // DIV.X
1250                     preSetDouble(F+fd,d);
1251                     pushDouble(F+fs,d);
1252                     pushDouble(F+ft,d);
1253                     a(d ? InstructionConstants.DDIV : InstructionConstants.FDIV);
1254                     setDouble(d);
1255                     break;
1256                 case 5: // ABS.X
1257                     preSetDouble(F+fd,d);
1258                     // NOTE: We can't use fneg/dneg here since they'll turn +0.0 into -0.0
1259
1260                     pushDouble(F+fs,d);
1261                     a(d ? InstructionConstants.DUP2 : InstructionConstants.DUP);
1262                     a(d ? InstructionConstants.DCONST_0 : InstructionConstants.FCONST_0);
1263                     a(d ? InstructionConstants.DCMPG : InstructionConstants.FCMPG);
1264
1265                     b1 = a(InstructionFactory.createBranchInstruction(IFGT,null));
1266                     a(d ? InstructionConstants.DCONST_0 : InstructionConstants.FCONST_0);
1267                     a(d ? InstructionConstants.DSUB : InstructionConstants.FSUB);
1268
1269                     b1.setTarget(setDouble(d));
1270
1271                     break;
1272                 case 6: // MOV.X
1273                     preSetReg(F+fd);
1274                     pushReg(F+fs);
1275                     setReg();
1276
1277                     if(d) {
1278                         preSetReg(F+fd+1);
1279                         pushReg(F+fs+1);
1280                         setReg();
1281                     }
1282
1283                     break;
1284                 case 7: // NEG.X
1285                     preSetDouble(F+fd,d);
1286                     pushDouble(F+fs,d);
1287                     a(d ? InstructionConstants.DNEG : InstructionConstants.FNEG);
1288                     setDouble(d);
1289                     break;
1290                 case 32: // CVT.S.X
1291                     preSetFloat(F+fd);
1292                     pushDouble(F+fs,d);
1293                     if(d) a(InstructionConstants.D2F);
1294                     setFloat();
1295                     break;
1296                 case 33: // CVT.D.X
1297                     preSetDouble(F+fd);
1298                     pushDouble(F+fs,d);
1299                     if(!d) a(InstructionConstants.F2D);
1300                     setDouble();
1301                     break;
1302                 case 36: { // CVT.W.D
1303                     int[] matches = new int[4];
1304                     for(int i=0;i<4;i++) matches[i] = i;
1305
1306                     TABLESWITCH ts = new  TABLESWITCH(matches,new InstructionHandle[4], null);
1307
1308                     preSetReg(F+fd);
1309                     pushDouble(F+fs,d);
1310                     pushReg(FCSR);
1311                     a(InstructionConstants.ICONST_3);
1312                     a(InstructionConstants.IAND);
1313                     a(ts);
1314
1315                     // Round towards plus infinity
1316                     ts.setTarget(2,a(InstructionConstants.NOP));
1317                     if(!d) a(InstructionConstants.F2D); // Ugh.. java.lang.Math doesn't have a float ceil/floor
1318                     a(fac.createInvoke("java.lang.Math","ceil",Type.DOUBLE,new Type[]{Type.DOUBLE},INVOKESTATIC));
1319                     if(!d) a(InstructionConstants.D2F);
1320                     b1 = a(InstructionFactory.createBranchInstruction(GOTO,null));
1321
1322                     // Round to nearest
1323                     ts.setTarget(0,d ? pushConst(0.5d) : pushConst(0.5f));
1324                     a(d ? InstructionConstants.DADD : InstructionConstants.FADD);
1325                     // fall through
1326
1327                     // Round towards minus infinity
1328                     ts.setTarget(3,a(InstructionConstants.NOP));
1329                     if(!d) a(InstructionConstants.F2D);
1330                     a(fac.createInvoke("java.lang.Math","floor",Type.DOUBLE,new Type[]{Type.DOUBLE},INVOKESTATIC));
1331                     if(!d) a(InstructionConstants.D2F);
1332
1333                     InstructionHandle h = a(d ? InstructionConstants.D2I : InstructionConstants.F2I);
1334                     setReg();
1335
1336                     ts.setTarget(1,h);
1337                     ts.setTarget(h);
1338                     b1.setTarget(h);
1339
1340                     break;
1341                 }
1342                 case 50: // C.EQ.D
1343                 case 60: // C.LT.D
1344                 case 62: // C.LE.D
1345                     preSetReg(FCSR);
1346                     pushReg(FCSR);
1347                     pushConst(~0x800000);
1348                     a(InstructionConstants.IAND);
1349                     pushDouble(F+fs,d);
1350                     pushDouble(F+ft,d);
1351                     a(d ? InstructionConstants.DCMPG : InstructionConstants.FCMPG);
1352                     switch(subcode) {
1353                         case 50: b1 = a(InstructionFactory.createBranchInstruction(IFEQ,null)); break;
1354                         case 60: b1 = a(InstructionFactory.createBranchInstruction(IFLT,null)); break;
1355                         case 62: b1 = a(InstructionFactory.createBranchInstruction(IFLE,null)); break;
1356                         default: b1 = null;
1357                     }
1358                     // FIXME: We probably don't need to pushConst(0x00000)
1359                     pushConst(0x000000);
1360                     b2 = a(InstructionFactory.createBranchInstruction(GOTO,null));
1361                     b1.setTarget(pushConst(0x800000));
1362                     b2.setTarget(a(InstructionConstants.IOR));
1363                     setReg();
1364                     break;
1365                 default: throw new Exn("Invalid Instruction 17/" + rs + "/" + subcode);
1366                 }
1367                 break;
1368             }
1369             case 20: { // Integer
1370                 switch(subcode) {
1371                 case 32: // CVT.S.W
1372                     preSetFloat(F+fd);
1373                     pushReg(F+fs);
1374                     a(InstructionConstants.I2F);
1375                     setFloat();
1376                     break;
1377                 case 33: // CVT.D.W
1378                     preSetDouble(F+fd);
1379                     pushReg(F+fs);
1380                     a(InstructionConstants.I2D);
1381                     setDouble();
1382                     break;
1383                 default: throw new Exn("Invalid Instruction 17/" + rs + "/" + subcode);
1384                 }
1385                 break;
1386             }
1387             default:
1388                 throw new Exn("Invalid Instruction 17/" + rs);
1389             }
1390             break;
1391         }
1392         case 18: case 19:
1393             throw new Exn("coprocessor 2 and 3 instructions not available");
1394         case 32: { // LB
1395             preSetReg(R+rt);
1396             addiu(R+rs,signedImmediate);
1397             setTmp();
1398             preMemRead();
1399             pushTmp();
1400             memRead(true);
1401             pushTmp();
1402
1403             a(InstructionConstants.ICONST_M1);
1404             a(InstructionConstants.IXOR);
1405             a(InstructionConstants.ICONST_3);
1406             a(InstructionConstants.IAND);
1407             a(InstructionConstants.ICONST_3);
1408             a(InstructionConstants.ISHL);
1409             a(InstructionConstants.IUSHR);
1410             a(InstructionConstants.I2B);
1411             setReg();
1412             break;
1413         }
1414         case 33: { // LH
1415             preSetReg(R+rt);
1416             addiu(R+rs,signedImmediate);
1417             setTmp();
1418             preMemRead();
1419             pushTmp();
1420             memRead(true);
1421             pushTmp();
1422
1423             a(InstructionConstants.ICONST_M1);
1424             a(InstructionConstants.IXOR);
1425             a(InstructionConstants.ICONST_2);
1426             a(InstructionConstants.IAND);
1427             a(InstructionConstants.ICONST_3);
1428             a(InstructionConstants.ISHL);
1429             a(InstructionConstants.IUSHR);
1430             a(InstructionConstants.I2S);
1431             setReg();
1432             break;
1433         }
1434         case 34: { // LWL;
1435             preSetReg(R+rt);
1436             addiu(R+rs,signedImmediate);
1437             setTmp(); // addr
1438
1439             pushRegWZ(R+rt);
1440             pushConst(0x00ffffff);
1441             pushTmp();
1442
1443             a(InstructionConstants.ICONST_M1);
1444             a(InstructionConstants.IXOR);
1445             a(InstructionConstants.ICONST_3);
1446             a(InstructionConstants.IAND);
1447             a(InstructionConstants.ICONST_3);
1448             a(InstructionConstants.ISHL);
1449             a(InstructionConstants.IUSHR);
1450             a(InstructionConstants.IAND);
1451
1452             preMemRead();
1453             pushTmp();
1454             memRead(true);
1455             pushTmp();
1456
1457             a(InstructionConstants.ICONST_3);
1458             a(InstructionConstants.IAND);
1459             a(InstructionConstants.ICONST_3);
1460             a(InstructionConstants.ISHL);
1461             a(InstructionConstants.ISHL);
1462             a(InstructionConstants.IOR);
1463
1464             setReg();
1465
1466             break;
1467
1468         }
1469         case 35: // LW
1470             preSetReg(R+rt);
1471             memRead(R+rs,signedImmediate);
1472             setReg();
1473             break;
1474         case 36: { // LBU
1475             preSetReg(R+rt);
1476             addiu(R+rs,signedImmediate);
1477             setTmp();
1478             preMemRead();
1479             pushTmp();
1480             memRead(true);
1481             pushTmp();
1482
1483             a(InstructionConstants.ICONST_M1);
1484             a(InstructionConstants.IXOR);
1485             a(InstructionConstants.ICONST_3);
1486             a(InstructionConstants.IAND);
1487             a(InstructionConstants.ICONST_3);
1488             a(InstructionConstants.ISHL);
1489             a(InstructionConstants.IUSHR);
1490             pushConst(0xff);
1491             a(InstructionConstants.IAND);
1492             setReg();
1493             break;
1494         }
1495         case 37: { // LHU
1496             preSetReg(R+rt);
1497             addiu(R+rs,signedImmediate);
1498             setTmp();
1499             preMemRead();
1500             pushTmp();
1501             memRead(true);
1502             pushTmp();
1503
1504             a(InstructionConstants.ICONST_M1);
1505             a(InstructionConstants.IXOR);
1506             a(InstructionConstants.ICONST_2);
1507             a(InstructionConstants.IAND);
1508             a(InstructionConstants.ICONST_3);
1509             a(InstructionConstants.ISHL);
1510             a(InstructionConstants.IUSHR);
1511
1512             // chars are unsigend so this works
1513             a(InstructionConstants.I2C);
1514             setReg();
1515             break;
1516         }
1517         case 38: { // LWR
1518             preSetReg(R+rt);
1519             addiu(R+rs,signedImmediate);
1520             setTmp(); // addr
1521
1522             pushRegWZ(R+rt);
1523             pushConst(0xffffff00);
1524             pushTmp();
1525
1526             a(InstructionConstants.ICONST_3);
1527             a(InstructionConstants.IAND);
1528             a(InstructionConstants.ICONST_3);
1529             a(InstructionConstants.ISHL);
1530             a(InstructionConstants.ISHL);
1531             a(InstructionConstants.IAND);
1532
1533             preMemRead();
1534             pushTmp();
1535             memRead(true);
1536             pushTmp();
1537
1538             a(InstructionConstants.ICONST_M1);
1539             a(InstructionConstants.IXOR);
1540             a(InstructionConstants.ICONST_3);
1541             a(InstructionConstants.IAND);
1542             a(InstructionConstants.ICONST_3);
1543             a(InstructionConstants.ISHL);
1544             a(InstructionConstants.IUSHR);
1545             a(InstructionConstants.IOR);
1546
1547
1548             setReg();
1549             break;
1550         }
1551         case 40: { // SB
1552             addiu(R+rs,signedImmediate);
1553             setTmp(); // addr
1554
1555             // FEATURE: DO the preMemRead(true) thing for the rest of the S* instructions
1556             preMemRead(true);
1557             pushTmp();
1558             memRead(true);
1559
1560             pushConst(0xff000000);
1561             pushTmp();
1562
1563             a(InstructionConstants.ICONST_3);
1564             a(InstructionConstants.IAND);
1565             a(InstructionConstants.ICONST_3);
1566             a(InstructionConstants.ISHL);
1567             a(InstructionConstants.IUSHR);
1568             a(InstructionConstants.ICONST_M1);
1569             a(InstructionConstants.IXOR);
1570             a(InstructionConstants.IAND);
1571
1572             if(rt != 0) {
1573                 pushReg(R+rt);
1574                 pushConst(0xff);
1575                 a(InstructionConstants.IAND);
1576             } else {
1577                 pushConst(0);
1578             }
1579             pushTmp();
1580
1581             a(InstructionConstants.ICONST_M1);
1582             a(InstructionConstants.IXOR);
1583             a(InstructionConstants.ICONST_3);
1584             a(InstructionConstants.IAND);
1585             a(InstructionConstants.ICONST_3);
1586             a(InstructionConstants.ISHL);
1587             a(InstructionConstants.ISHL);
1588             a(InstructionConstants.IOR);
1589
1590             memWrite();
1591
1592             break;
1593         }
1594         case 41: { // SH
1595             preMemWrite1();
1596
1597             addiu(R+rs,signedImmediate);
1598
1599             a(InstructionConstants.DUP);
1600             setTmp(); // addr
1601
1602             preMemWrite2(true);
1603
1604             preMemRead();
1605             pushTmp();
1606             memRead(true);
1607
1608             pushConst(0xffff);
1609             pushTmp();
1610
1611             a(InstructionConstants.ICONST_2);
1612             a(InstructionConstants.IAND);
1613             a(InstructionConstants.ICONST_3);
1614             a(InstructionConstants.ISHL);
1615             a(InstructionConstants.ISHL);
1616             a(InstructionConstants.IAND);
1617
1618             if(rt != 0) {
1619                 pushReg(R+rt);
1620                 pushConst(0xffff);
1621                 a(InstructionConstants.IAND);
1622             } else {
1623                 pushConst(0);
1624             }
1625             pushTmp();
1626
1627             a(InstructionConstants.ICONST_M1);
1628             a(InstructionConstants.IXOR);
1629             a(InstructionConstants.ICONST_2);
1630             a(InstructionConstants.IAND);
1631             a(InstructionConstants.ICONST_3);
1632             a(InstructionConstants.ISHL);
1633             a(InstructionConstants.ISHL);
1634             a(InstructionConstants.IOR);
1635
1636             memWrite();
1637
1638             break;
1639         }
1640         case 42: { // SWL
1641             preMemWrite1();
1642
1643             addiu(R+rs,signedImmediate);
1644             a(InstructionConstants.DUP);
1645             setTmp(); // addr
1646
1647             preMemWrite2(true);
1648
1649             preMemRead();
1650             pushTmp();
1651             memRead(true);
1652
1653             pushConst(0xffffff00);
1654             pushTmp();
1655
1656             a(InstructionConstants.ICONST_M1);
1657             a(InstructionConstants.IXOR);
1658             a(InstructionConstants.ICONST_3);
1659             a(InstructionConstants.IAND);
1660             a(InstructionConstants.ICONST_3);
1661             a(InstructionConstants.ISHL);
1662             a(InstructionConstants.ISHL);
1663             a(InstructionConstants.IAND);
1664
1665             pushRegWZ(R+rt);
1666             pushTmp();
1667
1668             a(InstructionConstants.ICONST_3);
1669             a(InstructionConstants.IAND);
1670             a(InstructionConstants.ICONST_3);
1671             a(InstructionConstants.ISHL);
1672             a(InstructionConstants.IUSHR);
1673             a(InstructionConstants.IOR);
1674
1675             memWrite();
1676             break;
1677
1678         }
1679         case 43: // SW
1680             preMemWrite1();
1681             preMemWrite2(R+rs,signedImmediate);
1682             pushRegZ(R+rt);
1683             memWrite();
1684             break;
1685         case 46: { // SWR
1686             preMemWrite1();
1687
1688             addiu(R+rs,signedImmediate);
1689             a(InstructionConstants.DUP);
1690             setTmp(); // addr
1691
1692             preMemWrite2(true);
1693
1694             preMemRead();
1695             pushTmp();
1696             memRead(true);
1697
1698             pushConst(0x00ffffff);
1699             pushTmp();
1700
1701             a(InstructionConstants.ICONST_3);
1702             a(InstructionConstants.IAND);
1703             a(InstructionConstants.ICONST_3);
1704             a(InstructionConstants.ISHL);
1705             a(InstructionConstants.IUSHR);
1706             a(InstructionConstants.IAND);
1707
1708             pushRegWZ(R+rt);
1709             pushTmp();
1710
1711             a(InstructionConstants.ICONST_M1);
1712             a(InstructionConstants.IXOR);
1713             a(InstructionConstants.ICONST_3);
1714             a(InstructionConstants.IAND);
1715             a(InstructionConstants.ICONST_3);
1716             a(InstructionConstants.ISHL);
1717             a(InstructionConstants.ISHL);
1718             a(InstructionConstants.IOR);
1719
1720             memWrite();
1721             break;
1722         }
1723         // This need to be atomic if we ever support threads (see SWC0/SC)
1724         case 48: // LWC0/LL
1725             preSetReg(R+rt);
1726             memRead(R+rs,signedImmediate);
1727             setReg();
1728             break;
1729
1730         case 49: // LWC1
1731             preSetReg(F+rt);
1732             memRead(R+rs,signedImmediate);
1733             setReg();
1734             break;
1735
1736         /* This needs to fail (set rt to 0) if the memory location was modified
1737          * between the LL and SC if we every support threads.
1738          */
1739         case 56: // SWC0/SC
1740             preSetReg(R+rt);
1741             preMemWrite1();
1742             preMemWrite2(R+rs,signedImmediate);
1743             pushReg(R+rt);
1744             memWrite();
1745             pushConst(1);
1746             setReg();
1747             break;
1748
1749         case 57: // SWC1
1750             preMemWrite1();
1751             preMemWrite2(R+rs,signedImmediate);
1752             pushReg(F+rt);
1753             memWrite();
1754             break;
1755         default:
1756             throw new Exn("Invalid Instruction: " + op + " at " + toHex(pc));
1757         }
1758         return false;
1759     }
1760
1761     // Helper functions for emitText
1762
1763     private static final int R = 0;
1764     private static final int F = 32;
1765     private static final int HI = 64;
1766     private static final int LO = 65;
1767     private static final int FCSR = 66;
1768     private static final int REG_COUNT=67;
1769
1770     private int[] regLocalMapping = new int[REG_COUNT];
1771     private int[] regLocalReadCount = new int[REG_COUNT];
1772     private int[] regLocalWriteCount = new int[REG_COUNT];
1773     private int nextAvailLocal;
1774
1775     private int getLocalForReg(int reg) {
1776         if(regLocalMapping[reg] != 0) return regLocalMapping[reg];
1777         if(nextAvailLocal == 0) nextAvailLocal = onePage ? 3 : 4;
1778         regLocalMapping[reg] = nextAvailLocal++;
1779         return regLocalMapping[reg];
1780     }
1781
1782     private void fixupRegs() {
1783         InstructionHandle prev = realStart;
1784         for(int i=0;i<REG_COUNT;i++) {
1785             if(regLocalMapping[i] == 0) continue;
1786
1787             prev = insnList.append(prev,InstructionConstants.ALOAD_0);
1788             prev = insnList.append(prev,fac.createFieldAccess(fullClassName,regField(i),Type.INT, GETFIELD));
1789             prev = insnList.append(prev,InstructionFactory.createStore(Type.INT,regLocalMapping[i]));
1790
1791             if(regLocalWriteCount[i] > 0) {
1792                 a(InstructionConstants.ALOAD_0);
1793                 a(InstructionFactory.createLoad(Type.INT,regLocalMapping[i]));
1794                 a(fac.createFieldAccess(fullClassName,regField(i),Type.INT, PUTFIELD));
1795             }
1796
1797             regLocalMapping[i] = regLocalReadCount[i] = regLocalWriteCount[i] = 0;
1798         }
1799         nextAvailLocal = 0;
1800     }
1801
1802     private void restoreChangedRegs() {
1803         for(int i=0;i<REG_COUNT;i++) {
1804             if(regLocalWriteCount[i] > 0) {
1805                 a(InstructionConstants.ALOAD_0);
1806                 a(InstructionFactory.createLoad(Type.INT,regLocalMapping[i]));
1807                 a(fac.createFieldAccess(fullClassName,regField(i),Type.INT, PUTFIELD));
1808             }
1809         }
1810     }
1811
1812     private static final String[] regField = {
1813             "r0","r1","r2","r3","r4","r5","r6","r7",
1814             "r8","r9","r10","r11","r12","r13","r14","r15",
1815             "r16","r17","r18","r19","r20","r21","r22","r23",
1816             "r24","r25","r26","r27","r28","r29","r30","r31",
1817
1818             "f0","f1","f2","f3","f4","f5","f6","f7",
1819             "f8","f9","f10","f11","f12","f13","f14","f15",
1820             "f16","f17","f18","f19","f20","f21","f22","f23",
1821             "f24","f25","f26","f27","f28","f29","f30","f31",
1822
1823             "hi","lo","fcsr"
1824     };
1825
1826     private static String regField(int reg) {
1827         return regField[reg];
1828
1829         /*String field;
1830         switch(reg) {
1831             case HI: field = "hi"; break;
1832             case LO: field = "lo"; break;
1833             case FCSR: field = "fcsr"; break;
1834             default:
1835                 if(reg > R && reg < R+32) regFieldR[reg-R];
1836                 else if(reg >= F && reg < F+32) return regFieldF[
1837                 else throw new IllegalArgumentException(""+reg);
1838         }
1839         return field;*/
1840     }
1841
1842     private boolean doLocal(int reg) {
1843         //return false;
1844         return reg == R+2 || reg == R+3 || reg == R+4 || reg == R+29;
1845     }
1846
1847     private InstructionHandle pushRegWZ(int reg) {
1848         if(reg == R+0) {
1849             warn.println("Warning: Pushing r0!");
1850             new Exception().printStackTrace(warn);
1851         }
1852         return pushRegZ(reg);
1853     }
1854
1855     private InstructionHandle pushRegZ(int reg) {
1856         if(reg == R+0) return pushConst(0);
1857         else return pushReg(reg);
1858     }
1859
1860
1861     private InstructionHandle pushReg(int reg) {
1862         InstructionHandle h;
1863         if(doLocal(reg)) {
1864             regLocalReadCount[reg]++;
1865             h = a(InstructionFactory.createLoad(Type.INT,getLocalForReg(reg)));
1866         } else {
1867             h = a(InstructionConstants.ALOAD_0);
1868             a(fac.createFieldAccess(fullClassName,regField(reg),Type.INT, GETFIELD));
1869         }
1870         return h;
1871     }
1872
1873     private int preSetRegStackPos;
1874     private int[] preSetRegStack = new int[8];
1875
1876     // This can push ONE or ZERO words to the stack. If it pushed one it returns true
1877     private boolean preSetReg(int reg) {
1878         regField(reg); // just to check for validity
1879         preSetRegStack[preSetRegStackPos] = reg;
1880         preSetRegStackPos++;
1881         if(doLocal(reg)) {
1882             return false;
1883         } else {
1884             a(InstructionConstants.ALOAD_0);
1885             return true;
1886         }
1887     }
1888
1889     private InstructionHandle setReg() {
1890         if(preSetRegStackPos==0) throw new RuntimeException("didn't do preSetReg");
1891         preSetRegStackPos--;
1892         int reg = preSetRegStack[preSetRegStackPos];
1893         InstructionHandle h;
1894         if(doLocal(reg)) {
1895             h = a(InstructionFactory.createStore(Type.INT,getLocalForReg(reg)));
1896             regLocalWriteCount[reg]++;
1897         } else {
1898             h = a(fac.createFieldAccess(fullClassName,regField(reg),Type.INT, PUTFIELD));
1899         }
1900         return h;
1901     }
1902
1903     private InstructionHandle preSetPC() { return a(InstructionConstants.ALOAD_0); }
1904     private InstructionHandle setPC() { return a(fac.createFieldAccess(fullClassName,"pc",Type.INT, PUTFIELD)); }
1905
1906     //unused - private InstructionHandle pushFloat(int reg) throws CompilationException { return pushDouble(reg,false); }
1907     //unused - private InstructionHandle pushDouble(int reg) throws CompilationException { return pushDouble(reg,true); }
1908     private InstructionHandle pushDouble(int reg, boolean d) throws Exn {
1909         if(reg < F || reg >= F+32) throw new IllegalArgumentException(""+reg);
1910         InstructionHandle h;
1911         if(d) {
1912             if(reg == F+31) throw new Exn("Tried to use a double in f31");
1913             h = pushReg(reg+1);
1914             a(InstructionConstants.I2L);
1915             pushConst(32);
1916             a(InstructionConstants.LSHL);
1917             pushReg(reg);
1918             a(InstructionConstants.I2L);
1919             pushConst(0xffffffffL);
1920             a(InstructionConstants.LAND);
1921             a(InstructionConstants.LOR);
1922             //p("invokestatic java/lang/Double/longBitsToDouble(J)D");
1923             a(fac.createInvoke("java.lang.Double","longBitsToDouble",Type.DOUBLE,new Type[]{Type.LONG},INVOKESTATIC));
1924         } else {
1925             h = pushReg(reg);
1926             a(fac.createInvoke("java.lang.Float","intBitsToFloat",Type.FLOAT,new Type[]{Type.INT},INVOKESTATIC));
1927         }
1928         return h;
1929     }
1930
1931     private void preSetFloat(int reg) { preSetDouble(reg,false); }
1932     private void preSetDouble(int reg) { preSetDouble(reg,true); }
1933     private void preSetDouble(int reg, boolean d) { preSetReg(reg); }
1934
1935     private InstructionHandle setFloat() throws Exn { return setDouble(false); }
1936     private InstructionHandle setDouble() throws Exn { return setDouble(true); }
1937     private InstructionHandle setDouble(boolean d) throws Exn {
1938         int reg = preSetRegStack[preSetRegStackPos-1];
1939         if(reg < F || reg >= F+32) throw new IllegalArgumentException(""+reg);
1940         //p("invokestatic java/lang/Double/doubleToLongBits(D)J");
1941         InstructionHandle h;
1942         if(d) {
1943             if(reg == F+31) throw new Exn("Tried to use a double in f31");
1944             h = a(fac.createInvoke("java.lang.Double","doubleToLongBits",Type.LONG,new Type[]{Type.DOUBLE},INVOKESTATIC));
1945             a(InstructionConstants.DUP2);
1946             pushConst(32);
1947             a(InstructionConstants.LUSHR);
1948             a(InstructionConstants.L2I);
1949             if(preSetReg(reg+1))
1950                 a(InstructionConstants.SWAP);
1951             setReg();
1952             a(InstructionConstants.L2I);
1953             setReg(); // preSetReg was already done for this by preSetDouble
1954         } else {
1955             h = a(fac.createInvoke("java.lang.Float","floatToRawIntBits",Type.INT,new Type[]{Type.FLOAT},INVOKESTATIC));
1956             setReg();
1957         }
1958         return h;
1959     }
1960
1961     private Hashtable intCache = new Hashtable();
1962
1963     private InstructionHandle pushConst(int n) {
1964         if(n >= -1 && n <= 5) {
1965             switch(n) {
1966                 case -1: return a(InstructionConstants.ICONST_M1);
1967                 case 0: return a(InstructionConstants.ICONST_0);
1968                 case 1: return a(InstructionConstants.ICONST_1);
1969                 case 2: return a(InstructionConstants.ICONST_2);
1970                 case 3: return a(InstructionConstants.ICONST_3);
1971                 case 4: return a(InstructionConstants.ICONST_4);
1972                 case 5: return a(InstructionConstants.ICONST_5);
1973                 default: return null;
1974             }
1975         } else if(n >= -128 && n <= 127) {
1976             return a(new BIPUSH((byte) n));
1977         } else if(n >= -32768 && n <= 32767) {
1978             return a(new SIPUSH((short) n));
1979         } else {
1980             return a(new PUSH(cp,n));
1981         }
1982     }
1983
1984     private InstructionHandle pushConst(long l) { return a(new PUSH(cp,l)); }
1985     private InstructionHandle pushConst(float f) { return a(new PUSH(cp,f)); }
1986     private InstructionHandle pushConst(double d) { return a(new PUSH(cp,d)); }
1987
1988     private void pushTmp() { a(InstructionConstants.ILOAD_1); }
1989     private void setTmp() { a(InstructionConstants.ISTORE_1); }
1990
1991     private void addiu(int reg, int offset) {
1992         if(reg != R+0 && offset != 0) {
1993             pushReg(reg);
1994             pushConst(offset);
1995             a(InstructionConstants.IADD);
1996         } else if(reg != R+0) {
1997             pushReg(reg);
1998         } else {
1999             pushConst(offset);
2000         }
2001     }
2002     private int memWriteStage;
2003     private void preMemWrite1() {
2004         if(memWriteStage!=0) throw new Error("pending preMemWrite1/2");
2005         memWriteStage=1;
2006         if(onePage)
2007             a(InstructionConstants.ALOAD_2);
2008         else if(fastMem)
2009             a(InstructionFactory.createLoad(Type.OBJECT,3));
2010         else
2011             a(InstructionConstants.ALOAD_0);
2012     }
2013
2014     private void preMemWrite2(int reg, int offset) {
2015         addiu(reg,offset);
2016         preMemWrite2();
2017     }
2018
2019     private void preMemWrite2() { preMemWrite2(false); }
2020     private void preMemWrite2(boolean addrInTmp) {
2021         if(memWriteStage!=1) throw new Error("pending preMemWrite2 or no preMemWrite1");
2022         memWriteStage=2;
2023
2024         if(nullPointerCheck) {
2025             a(InstructionConstants.DUP);
2026             a(InstructionConstants.ALOAD_0);
2027             a(InstructionConstants.SWAP);
2028             a(fac.createInvoke(fullClassName,"nullPointerCheck",Type.VOID,new Type[]{Type.INT},INVOKEVIRTUAL));
2029         }
2030
2031         if(onePage) {
2032             a(InstructionConstants.ICONST_2);
2033             a(InstructionConstants.IUSHR);
2034         } else if(fastMem) {
2035             if(!addrInTmp)
2036                 a(InstructionConstants.DUP_X1);
2037             pushConst(pageShift);
2038             a(InstructionConstants.IUSHR);
2039             a(InstructionConstants.AALOAD);
2040             if(addrInTmp)
2041                 pushTmp();
2042             else
2043                 a(InstructionConstants.SWAP);
2044             a(InstructionConstants.ICONST_2);
2045             a(InstructionConstants.IUSHR);
2046             pushConst((pageSize>>2)-1);
2047             a(InstructionConstants.IAND);
2048         }
2049     }
2050
2051     // pops an address and value off the stack, sets *addr to value
2052     private void memWrite() {
2053         if(memWriteStage!=2) throw new Error("didn't do preMemWrite1 or preMemWrite2");
2054         memWriteStage=0;
2055
2056         if(onePage) {
2057             a(InstructionConstants.IASTORE);
2058         } else if(fastMem) {
2059             a(InstructionConstants.IASTORE);
2060         } else {
2061             a(fac.createInvoke(fullClassName,"unsafeMemWrite",Type.VOID,new Type[]{Type.INT,Type.INT},INVOKEVIRTUAL));
2062         }
2063
2064     }
2065
2066     // reads the word at r[reg]+offset
2067     private void memRead(int reg, int offset) {
2068         preMemRead();
2069         addiu(reg,offset);
2070         memRead();
2071     }
2072
2073     private boolean didPreMemRead;
2074     private boolean preMemReadDoPreWrite;
2075
2076     private void preMemRead() { preMemRead(false); }
2077     private void preMemRead(boolean preWrite) {
2078         if(didPreMemRead) throw new Error("pending preMemRead");
2079         didPreMemRead = true;
2080         preMemReadDoPreWrite = preWrite;
2081         if(onePage)
2082             a(InstructionConstants.ALOAD_2);
2083         else if(fastMem)
2084             a(InstructionFactory.createLoad(Type.OBJECT,preWrite ? 3 : 2));
2085         else
2086             a(InstructionConstants.ALOAD_0);
2087     }
2088     // memRead pops an address off the stack, reads the value at that addr, and pushed the value
2089     // preMemRead MUST be called BEFORE the addresses is pushed
2090     private void memRead() { memRead(false); }
2091
2092     private void memRead(boolean addrInTmp) {
2093         if(!didPreMemRead) throw new Error("didn't do preMemRead");
2094         didPreMemRead = false;
2095         if(preMemReadDoPreWrite)
2096             memWriteStage=2;
2097
2098         if(nullPointerCheck) {
2099             a(InstructionConstants.DUP);
2100             a(InstructionConstants.ALOAD_0);
2101             a(InstructionConstants.SWAP);
2102             a(fac.createInvoke(fullClassName,"nullPointerCheck",Type.VOID,new Type[]{Type.INT},INVOKEVIRTUAL));
2103         }
2104
2105         if(onePage) {
2106             // p(target + "= page[(" + addr + ")>>>2];");
2107             a(InstructionConstants.ICONST_2);
2108             a(InstructionConstants.IUSHR);
2109             if(preMemReadDoPreWrite)
2110                 a(InstructionConstants.DUP2);
2111             a(InstructionConstants.IALOAD);
2112         } else if(fastMem) {
2113             //p(target  + " = readPages[("+addr+")>>>"+pageShift+"][(("+addr+")>>>2)&"+toHex((pageSize>>2)-1)+"];");
2114
2115             if(!addrInTmp)
2116                 a(InstructionConstants.DUP_X1);
2117             pushConst(pageShift);
2118             a(InstructionConstants.IUSHR);
2119             a(InstructionConstants.AALOAD);
2120             if(addrInTmp)
2121                 pushTmp();
2122             else
2123                 a(InstructionConstants.SWAP);
2124             a(InstructionConstants.ICONST_2);
2125             a(InstructionConstants.IUSHR);
2126             pushConst((pageSize>>2)-1);
2127             a(InstructionConstants.IAND);
2128             if(preMemReadDoPreWrite)
2129                 a(InstructionConstants.DUP2);
2130             a(InstructionConstants.IALOAD);
2131
2132         } else {
2133             if(preMemReadDoPreWrite)
2134                 a(InstructionConstants.DUP2);
2135             a(fac.createInvoke(fullClassName,"unsafeMemWrite",Type.INT,new Type[]{Type.INT},INVOKEVIRTUAL));
2136         }
2137     }
2138
2139
2140     // This might come in handy for something else
2141     /*private boolean touchesReg(int insn, int reg) {
2142         if((reg < R+0 || reg >= R+32) && reg != FCSR) throw new IllegalArgumentException(""+reg);
2143         if(reg == R+0) return false; // r0 is never modified
2144         int op = (insn >>> 26) & 0xff;                 // bits 26-31
2145         int subcode = insn & 0x3f;                     // bits 0-5
2146         int rd = (insn >>> 11) & 0x1f;                 // bits 11-15
2147         int rt = (insn >>> 16) & 0x1f;                 // bits 16-20
2148         int rs = (insn >>> 21) & 0x1f;                 // bits 21-25
2149
2150         switch(op) {
2151         case 0:
2152             if(subcode >= 0 && subcode <= 7) return reg == R+rd; // Shift ops
2153             if(subcode >= 32 && subcode <= 43) return reg == R+rd; // Other math ops
2154             if(subcode >= 24 && subcode <= 27) return reg == HI || reg == LO; // MULT/DIV
2155             break;
2156         case 13: return false; // BREAK
2157         case 17:
2158             switch(rs) {
2159                 case 0: return reg == R+rt; // MFC.1
2160                 case 2: return reg == R+rt; // CFC.1
2161                 case 4: return false; // MTC.1
2162                 case 6: return false; // CTC.1
2163                 case 16: // Single
2164                 case 17: // Double
2165                     if(subcode == 50 || subcode == 60 || subcode == 62) return reg == FCSR;
2166                     return false; // everything else just touches f0-f31
2167                 case 20: return false; // Integer - just touches f0-f31
2168             }
2169             break;
2170         default:
2171             if(op >= 8 && op <= 15) return reg == R+rt; // XXXI instructions
2172             if(op >= 40 && op <= 46) return false; // Memory WRITE ops
2173             if(op == 49) return reg == F+rt; // LWC1
2174             if(op == 57) return false; // SWC1
2175             break;
2176         }
2177         warn.println("Unknown instruction in touchesReg()- assuming it modifies all regs " + op + " " + subcode);
2178         new Exception().fillInStackTrace().printStackTrace(warn);
2179         return true;
2180     }*/
2181 }