1 package org.ibex.nestedvm;
5 import org.ibex.nestedvm.util.*;
6 import org.ibex.classgen.*;
8 // FEATURE: Eliminate unnecessary use of SWAP
9 // FEATURE: Put regs in low (<=3) local vars, small classfile size
11 /* FEATURE: Span large binaries across several classfiles
12 * We should be able to do this with no performance penalty
13 * Every method in the inner classes is static and takes the main class as an arg
14 * This makes them look just like methods in the main class because arg1 gets loaded into
18 /* FEATURE: smarter with local regs
19 * Be even smarter with the use of local registers. We need to only load fields into
20 * local regs when they are actually used and only write to fields if the regs could have
21 * changed. This should allow us to put more regs in local vars. Right now putting all used
22 * regs local vars makes code like this slower.
24 * void work(int a, int b) {
31 * Because all the regs used in "real work" are loaded/restored even for fast path
35 public class ClassFileCompiler extends Compiler implements CGConst {
36 private static final boolean OPTIMIZE_CP = true;
38 /** The stream to write the compiled output to */
39 private OutputStream os;
41 private PrintStream warn = System.err;
43 private final Type.Object me;
46 private MethodGen clinit, init;
48 public ClassFileCompiler(String path, String className, OutputStream os) throws IOException { this(new Seekable.File(path),className,os); }
49 public ClassFileCompiler(Seekable binary, String className, OutputStream os) throws IOException {
50 this(binary,className);
51 if(os == null) throw new NullPointerException();
54 public ClassFileCompiler(Seekable binary, String className, File outDir) throws IOException {
55 this(binary,className);
56 if(outDir == null) throw new NullPointerException();
59 private ClassFileCompiler(Seekable binary, String className) throws IOException {
60 super(binary,className);
61 me = new Type.Object(fullClassName);
64 public void setWarnWriter(PrintStream warn) { this.warn = warn; }
66 protected void _go() throws Exn, IOException {
69 } catch(ClassGen.Exn e) {
70 e.printStackTrace(warn);
71 throw new Exn("Class generation exception: " + e.toString());
75 private void __go() throws Exn, IOException {
76 if(!pruneCases) throw new Exn("-o prunecases MUST be enabled for ClassFileCompiler");
79 Type.Object superClass = new Type.Object(runtimeClass);
80 cg = new ClassGen(me,superClass,ACC_PUBLIC|ACC_FINAL|ACC_SUPER);
81 if(source != null) cg.setSourceFile(source);
84 cg.addField("pc",Type.INT,ACC_PRIVATE);
85 cg.addField("hi",Type.INT,ACC_PRIVATE);
86 cg.addField("lo",Type.INT,ACC_PRIVATE);
87 cg.addField("fcsr",Type.INT,ACC_PRIVATE);
88 for(int i=1;i<32;i++) cg.addField("r" + i,Type.INT,ACC_PRIVATE);
89 for(int i=0;i<32;i++) cg.addField("f" + i,singleFloat ? Type.FLOAT : Type.INT,ACC_PRIVATE);
92 clinit = cg.addMethod("<clinit>",Type.VOID,Type.NO_ARGS,ACC_PRIVATE|ACC_STATIC);
95 init = cg.addMethod("<init>",Type.VOID,Type.NO_ARGS,ACC_PUBLIC);
97 init.add(LDC,pageSize);
98 init.add(LDC,totalPages);
99 init.add(INVOKESPECIAL,new MethodRef(me,"<init>",Type.VOID,new Type[]{Type.INT,Type.INT}));
103 init = cg.addMethod("<init>",Type.VOID,new Type[]{Type.BOOLEAN},ACC_PUBLIC);
105 init.add(LDC,pageSize);
106 init.add(LDC,totalPages);
108 init.add(INVOKESPECIAL,new MethodRef(me,"<init>",Type.VOID,new Type[]{Type.INT,Type.INT,Type.BOOLEAN}));
112 init = cg.addMethod("<init>",Type.VOID,new Type[]{Type.INT,Type.INT},ACC_PUBLIC);
117 init.add(INVOKESPECIAL,new MethodRef(me,"<init>",Type.VOID,new Type[]{Type.INT,Type.INT,Type.BOOLEAN}));
121 init = cg.addMethod("<init>",Type.VOID,new Type[]{Type.INT,Type.INT,Type.BOOLEAN},ACC_PUBLIC);
126 init.add(INVOKESPECIAL,new MethodRef(superClass,"<init>",Type.VOID,new Type[]{Type.INT,Type.INT,Type.BOOLEAN}));
129 cg.addField("page",Type.arrayType(Type.INT),ACC_PRIVATE|ACC_FINAL);
132 init.add(GETFIELD,new FieldRef(me,"readPages",Type.arrayType(Type.INT,2)));
135 init.add(PUTFIELD,new FieldRef(me,"page",Type.arrayType(Type.INT)));
139 cg.addField("symbols",new Type.Object(hashClass),ACC_PRIVATE|ACC_STATIC|ACC_FINAL);
143 for(int i=0;i<elf.sheaders.length;i++) {
144 ELF.SHeader sheader = elf.sheaders[i];
145 String name = sheader.name;
146 // if this section doesn't get loaded into our address space don't worry about it
147 if(sheader.addr == 0x0) continue;
149 highestAddr = Math.max(highestAddr, sheader.addr + sheader.size);
151 if(name.equals(".text"))
152 emitText(sheader.addr, new DataInputStream(sheader.getInputStream()),sheader.size);
153 else if(name.equals(".data") || name.equals(".sdata") || name.equals(".rodata") || name.equals(".ctors") || name.equals(".dtors"))
154 emitData(sheader.addr, new DataInputStream(sheader.getInputStream()), sheader.size,name.equals(".rodata"));
155 else if(name.equals(".bss") || name.equals(".sbss"))
156 emitBSS(sheader.addr,sheader.size);
158 throw new Exn("Unknown segment: " + name);
166 Type.Object hash = new Type.Object(hashClass);
167 clinit.add(NEW,hash);
170 clinit.add(INVOKESPECIAL,new MethodRef(hash,"<init>",Type.VOID,Type.NO_ARGS));
171 clinit.add(PUTSTATIC,new FieldRef(me,"symbols",hash));
172 ELF.Symbol[] symbols = elf.getSymtab().symbols;
173 for(int i=0;i<symbols.length;i++) {
174 ELF.Symbol s = symbols[i];
175 if(s.type == ELF.Symbol.STT_FUNC && s.binding == ELF.Symbol.STB_GLOBAL && (s.name.equals("_call_helper") || !s.name.startsWith("_"))) {
177 clinit.add(LDC,s.name);
178 clinit.add(NEW,Type.INTEGER_OBJECT);
180 clinit.add(LDC,s.addr);
181 clinit.add(INVOKESPECIAL,new MethodRef(Type.INTEGER_OBJECT,"<init>",Type.VOID,new Type[]{Type.INT}));
182 clinit.add(INVOKEVIRTUAL,new MethodRef(hash,"put",Type.OBJECT,new Type[]{Type.OBJECT,Type.OBJECT}));
191 ELF.SHeader text = elf.sectionWithName(".text");
194 MethodGen tramp = cg.addMethod("trampoline",Type.VOID,Type.NO_ARGS,ACC_PRIVATE);
196 int start = tramp.size();
198 tramp.add(GETFIELD,new FieldRef(me,"state",Type.INT));
199 tramp.add(IFEQ,tramp.size()+2);
204 tramp.add(GETFIELD,new FieldRef(me,"pc",Type.INT));
205 tramp.add(LDC,methodShift);
208 int beg = text.addr >>> methodShift;
209 int end = ((text.addr + text.size + maxBytesPerMethod - 1) >>> methodShift);
211 MethodGen.TSI tsi = new MethodGen.TSI(beg,end-1);
212 tramp.add(TABLESWITCH,tsi);
213 for(int n=beg;n<end;n++) {
214 tsi.setTargetForVal(n,tramp.size());
215 tramp.add(INVOKESPECIAL,new MethodRef(me,"run_"+toHex(n<<methodShift),Type.VOID,Type.NO_ARGS));
216 tramp.add(GOTO,start);
218 tsi.setDefaultTarget(tramp.size());
221 tramp.add(NEW,new Type.Object("org.ibex.nestedvm.Runtime$ExecutionException"));
223 tramp.add(NEW, Type.STRINGBUFFER);
225 tramp.add(LDC,"Jumped to invalid address in trampoline (r2: ");
226 tramp.add(INVOKESPECIAL,new MethodRef(Type.STRINGBUFFER,"<init>",Type.VOID,new Type[]{Type.STRING}));
228 tramp.add(GETFIELD, new FieldRef(me,"r2",Type.INT));
229 tramp.add(INVOKEVIRTUAL,new MethodRef(Type.STRINGBUFFER,"append",Type.STRINGBUFFER,new Type[]{Type.INT}));
230 tramp.add(LDC," pc: ");
231 tramp.add(INVOKEVIRTUAL,new MethodRef(Type.STRINGBUFFER,"append",Type.STRINGBUFFER,new Type[]{Type.STRING}));
233 tramp.add(GETFIELD, new FieldRef(me,"pc",Type.INT));
234 tramp.add(INVOKEVIRTUAL,new MethodRef(Type.STRINGBUFFER,"append",Type.STRINGBUFFER,new Type[]{Type.INT}));
236 tramp.add(INVOKEVIRTUAL,new MethodRef(Type.STRINGBUFFER,"append",Type.STRINGBUFFER,new Type[]{Type.STRING}));
237 tramp.add(INVOKEVIRTUAL,new MethodRef(Type.STRINGBUFFER,"toString",Type.STRING,Type.NO_ARGS));
238 tramp.add(INVOKESPECIAL,new MethodRef(new Type.Object("org.ibex.nestedvm.Runtime$ExecutionException"),"<init>",Type.VOID,new Type[]{Type.STRING}));
245 } catch(ClassGen.Exn e) {
246 e.printStackTrace(warn);
247 throw new Exn("Generation of the trampoline method failed. Try increasing maxInsnPerMethod");
251 addConstReturnMethod("gp",gp.addr);
252 addConstReturnMethod("entryPoint",elf.header.entry);
253 addConstReturnMethod("heapStart",highestAddr);
255 if(userInfo != null) {
256 addConstReturnMethod("userInfoBase",userInfo.addr);
257 addConstReturnMethod("userInfoSize",userInfo.size);
261 Type.Object hashClassType = new Type.Object(hashClass);
262 MethodGen ls = cg.addMethod("lookupSymbol",Type.INT,new Type[]{Type.STRING},ACC_PROTECTED);
263 ls.add(GETSTATIC,new FieldRef(me,"symbols",hashClassType));
265 ls.add(INVOKEVIRTUAL,new MethodRef(hashClassType,"get",Type.OBJECT,new Type[]{Type.OBJECT}));
267 int b = ls.add(IFNULL);
268 ls.add(CHECKCAST,Type.INTEGER_OBJECT);
269 ls.add(INVOKEVIRTUAL,new MethodRef(Type.INTEGER_OBJECT,"intValue",Type.INT,Type.NO_ARGS));
271 ls.setArg(b,ls.size());
277 Type.Object cpuStateType = new Type.Object("org.ibex.nestedvm.Runtime$CPUState");
278 MethodGen setCPUState = cg.addMethod("setCPUState",Type.VOID,new Type[]{cpuStateType},ACC_PROTECTED);
279 MethodGen getCPUState = cg.addMethod("getCPUState",Type.VOID,new Type[]{cpuStateType},ACC_PROTECTED);
281 setCPUState.add(ALOAD_1);
282 getCPUState.add(ALOAD_1);
283 setCPUState.add(GETFIELD,new FieldRef(cpuStateType,"r",Type.arrayType(Type.INT)));
284 getCPUState.add(GETFIELD,new FieldRef(cpuStateType,"r",Type.arrayType(Type.INT)));
285 setCPUState.add(ASTORE_2);
286 getCPUState.add(ASTORE_2);
288 for(int i=1;i<32;i++) {
289 setCPUState.add(ALOAD_0);
290 setCPUState.add(ALOAD_2);
291 setCPUState.add(LDC,i);
292 setCPUState.add(IALOAD);
293 setCPUState.add(PUTFIELD,new FieldRef(me,"r"+i,Type.INT));
295 getCPUState.add(ALOAD_2);
296 getCPUState.add(LDC,i);
297 getCPUState.add(ALOAD_0);
298 getCPUState.add(GETFIELD,new FieldRef(me,"r"+i,Type.INT));
299 getCPUState.add(IASTORE);
302 setCPUState.add(ALOAD_1);
303 getCPUState.add(ALOAD_1);
304 setCPUState.add(GETFIELD,new FieldRef(cpuStateType,"f",Type.arrayType(Type.INT)));
305 getCPUState.add(GETFIELD,new FieldRef(cpuStateType,"f",Type.arrayType(Type.INT)));
306 setCPUState.add(ASTORE_2);
307 getCPUState.add(ASTORE_2);
309 for(int i=0;i<32;i++) {
310 setCPUState.add(ALOAD_0);
311 setCPUState.add(ALOAD_2);
312 setCPUState.add(LDC,i);
313 setCPUState.add(IALOAD);
314 if(singleFloat) setCPUState.add(INVOKESTATIC,new MethodRef(Type.FLOAT_OBJECT,"intBitsToFloat",Type.FLOAT,new Type[]{Type.INT}));
315 setCPUState.add(PUTFIELD,new FieldRef(me,"f"+i,singleFloat ? Type.FLOAT : Type.INT));
317 getCPUState.add(ALOAD_2);
318 getCPUState.add(LDC,i);
319 getCPUState.add(ALOAD_0);
320 getCPUState.add(GETFIELD,new FieldRef(me,"f"+i,singleFloat ? Type.FLOAT: Type.INT));
321 if(singleFloat) getCPUState.add(INVOKESTATIC,new MethodRef(Type.FLOAT_OBJECT,"floatToIntBits",Type.INT,new Type[]{Type.FLOAT}));
322 getCPUState.add(IASTORE);
325 String[] each = new String[] { "hi","lo","fcsr","pc" };
326 for(int i=0;i<each.length;i++) {
327 setCPUState.add(ALOAD_0);
328 setCPUState.add(ALOAD_1);
329 setCPUState.add(GETFIELD,new FieldRef(cpuStateType,each[i],Type.INT));
330 setCPUState.add(PUTFIELD,new FieldRef(me,each[i],Type.INT));
332 getCPUState.add(ALOAD_1);
333 getCPUState.add(ALOAD_0);
334 getCPUState.add(GETFIELD,new FieldRef(me,each[i],Type.INT));
335 getCPUState.add(PUTFIELD,new FieldRef(cpuStateType,each[i],Type.INT));
337 setCPUState.add(RETURN);
338 getCPUState.add(RETURN);
341 MethodGen execute = cg.addMethod("_execute",Type.VOID,Type.NO_ARGS,ACC_PROTECTED);
342 int tryStart = execute.size();
343 execute.add(ALOAD_0);
344 execute.add(INVOKESPECIAL,new MethodRef(me,"trampoline",Type.VOID,Type.NO_ARGS));
345 int tryEnd = execute.size();
348 int catchInsn = execute.size();
349 execute.add(ASTORE_1);
350 execute.add(NEW, new Type.Object("org.ibex.nestedvm.Runtime$FaultException"));
352 execute.add(ALOAD_1);
353 execute.add(INVOKESPECIAL,new MethodRef("org.ibex.nestedvm.Runtime$FaultException","<init>",Type.VOID,new Type[]{new Type.Object("java.lang.RuntimeException")}));
356 execute.addExceptionHandler(tryStart,tryEnd,catchInsn,new Type.Object("java.lang.RuntimeException"));
357 execute.addThrow(new Type.Object("org.ibex.nestedvm.Runtime$ExecutionException"));
359 MethodGen main = cg.addMethod("main",Type.VOID,new Type[]{Type.arrayType(Type.STRING)},ACC_STATIC|ACC_PUBLIC);
362 main.add(INVOKESPECIAL,new MethodRef(me,"<init>",Type.VOID,Type.NO_ARGS));
363 main.add(LDC,fullClassName);
366 Type.Object ur = new Type.Object("org.ibex.nestedvm.UnixRuntime");
367 main.add(INVOKESTATIC,new MethodRef(ur,"runAndExec",Type.INT,new Type[]{ur,Type.STRING,Type.arrayType(Type.STRING)}));
369 main.add(INVOKEVIRTUAL,new MethodRef(me,"run",Type.INT,new Type[]{Type.STRING,Type.arrayType(Type.STRING)}));
371 main.add(INVOKESTATIC,new MethodRef(new Type.Object("java.lang.System"),"exit",Type.VOID,new Type[]{Type.INT}));
375 if(!outDir.isDirectory()) throw new IOException("" + outDir + " isn't a directory");
382 private void addConstReturnMethod(String name, int val) {
383 MethodGen m = cg.addMethod(name,Type.INT,Type.NO_ARGS,ACC_PROTECTED);
388 private static int initDataCount;
389 private void emitData(int addr, DataInputStream dis, int size, boolean readOnly) throws Exn,IOException {
390 if((addr&3)!=0 || (size&3)!=0) throw new Exn("Data section on weird boundaries");
391 int last = addr + size;
393 int segSize = Math.min(size,28000); // must be a multiple of 56
394 StringBuffer sb = new StringBuffer();
395 for(int i=0;i<segSize;i+=7) {
397 for(int j=0;j<7;j++) {
399 byte b = (i+j < size) ? dis.readByte() : 1;
403 sb.append((char) ((l>>>(7*(7-j)))&0x7f));
405 String fieldname = "_data" + (++initDataCount);
406 cg.addField(fieldname,Type.arrayType(Type.INT),ACC_PRIVATE|ACC_STATIC|ACC_FINAL);
408 clinit.add(LDC,sb.toString());
409 clinit.add(LDC,segSize/4);
410 clinit.add(INVOKESTATIC,new MethodRef(new Type.Object("org.ibex.nestedvm.Runtime"),"decodeData",Type.arrayType(Type.INT),new Type[]{Type.STRING,Type.INT}));
411 clinit.add(PUTSTATIC,new FieldRef(me,fieldname,Type.arrayType(Type.INT)));
414 init.add(GETSTATIC,new FieldRef(me,fieldname,Type.arrayType(Type.INT)));
416 init.add(LDC,readOnly ? 1 : 0);
417 init.add(INVOKEVIRTUAL,new MethodRef(me,"initPages",Type.VOID,new Type[]{Type.arrayType(Type.INT),Type.INT,Type.BOOLEAN}));
425 private void emitBSS(int addr, int size) throws Exn {
426 if((addr&3)!=0) throw new Exn("BSS section on weird boundaries");
433 init.add(INVOKEVIRTUAL,new MethodRef(me,"clearPages",Type.VOID,new Type[]{Type.INT,Type.INT}));
437 private int startOfMethod = 0; // the start of this method (not necessarily the first instruction)
438 private int endOfMethod = 0; // the maximum end of this method (could end before it is full)
440 private MethodGen.PhantomTarget returnTarget; // where to jump when exiting the method
441 private MethodGen.PhantomTarget defaultTarget; // the default switch target (throws exn)
442 private MethodGen.PhantomTarget[] insnTargets; // the targets for each jumpable instruction
443 private MethodGen mg; // the method itself
445 private boolean jumpable(int addr) { return jumpableAddresses.get(new Integer(addr)) != null; }
447 private static final int UNREACHABLE = 1;
448 private static final int SKIP_NEXT = 2;
450 private boolean textDone; // a text segment was already processed
451 private void emitText(int addr, DataInputStream dis, int size) throws Exn,IOException {
452 if(textDone) throw new Exn("Multiple text segments");
455 if((addr&3)!=0 || (size&3)!=0) throw new Exn("Section on weird boundaries");
457 int insn,nextInsn=-1;
459 boolean skipNext = true;
460 boolean unreachable = false;
462 for(int i=0;i<count;i++,addr+=4) {
463 insn = skipNext ? dis.readInt() : nextInsn;
464 nextInsn = (i == count-1) ? -1 : dis.readInt();
465 if(addr >= endOfMethod) { endMethod(addr,unreachable); startMethod(addr); }
466 if(insnTargets[i%maxInsnPerMethod] != null) {
467 insnTargets[i%maxInsnPerMethod].setTarget(mg.size());
469 } else if(unreachable) {
473 int ret = emitInstruction(addr,insn,nextInsn);
474 unreachable = (ret & UNREACHABLE) != 0;
475 skipNext = (ret & SKIP_NEXT) != 0;
477 e.printStackTrace(warn);
478 warn.println("Exception at " + toHex(addr));
480 } catch(RuntimeException e) {
481 warn.println("Exception at " + toHex(addr));
484 if(skipNext) { addr+=4; i++; }
486 endMethod(0,unreachable);
490 private void startMethod(int first) {
491 startOfMethod = first & methodMask;
492 endOfMethod = startOfMethod + maxBytesPerMethod;
494 mg = cg.addMethod("run_" + toHex(startOfMethod),Type.VOID,Type.NO_ARGS,ACC_PRIVATE|ACC_FINAL);
497 mg.add(GETFIELD,new FieldRef(me,"page",Type.arrayType(Type.INT)));
501 mg.add(GETFIELD,new FieldRef(me,"readPages",Type.arrayType(Type.INT,2)));
504 mg.add(GETFIELD,new FieldRef(me,"writePages",Type.arrayType(Type.INT,2)));
508 returnTarget = new MethodGen.PhantomTarget();
509 insnTargets = new MethodGen.PhantomTarget[maxBytesPerMethod/4];
511 int[] buf = new int[maxBytesPerMethod/4];
512 Object[] targetBuf = new Object[maxBytesPerMethod/4];
514 for(int addr=first;addr<endOfMethod;addr+=4) {
516 targetBuf[n] = insnTargets[(addr-startOfMethod)/4] = new MethodGen.PhantomTarget();
522 MethodGen.LSI lsi = new MethodGen.LSI(n);
523 System.arraycopy(buf,0,lsi.vals,0,n);
524 System.arraycopy(targetBuf,0,lsi.targets,0,n);
525 lsi.setDefaultTarget(defaultTarget = new MethodGen.PhantomTarget());
530 mg.add(GETFIELD,new FieldRef(me,"pc",Type.INT));
531 mg.add(LOOKUPSWITCH,lsi);
534 private void endMethod(int firstAddrOfNext,boolean unreachable) {
535 if(startOfMethod == 0) return;
539 mg.add(LDC,firstAddrOfNext);
541 // mark the start of the next method as jumpable
542 jumpableAddresses.put(new Integer(firstAddrOfNext),Boolean.TRUE);
545 returnTarget.setTarget(mg.size());
551 defaultTarget.setTarget(mg.size());
554 mg.add(NEW,new Type.Object("org.ibex.nestedvm.Runtime$ExecutionException"));
556 mg.add(NEW,Type.STRINGBUFFER);
558 mg.add(LDC,"Jumped to invalid address: ");
559 mg.add(INVOKESPECIAL,new MethodRef(Type.STRINGBUFFER,"<init>",Type.VOID,new Type[]{Type.STRING}));
561 mg.add(GETFIELD,new FieldRef(me,"pc",Type.INT));
562 mg.add(INVOKEVIRTUAL,new MethodRef(Type.STRINGBUFFER,"append",Type.STRINGBUFFER,new Type[]{Type.INT}));
563 mg.add(INVOKEVIRTUAL,new MethodRef(Type.STRINGBUFFER,"toString",Type.STRING,Type.NO_ARGS));
564 mg.add(INVOKESPECIAL,new MethodRef(new Type.Object("org.ibex.nestedvm.Runtime$ExecutionException"),"<init>",Type.VOID,new Type[]{Type.STRING}));
567 mg.add(NEW,new Type.Object("org.ibex.nestedvm.Runtime$ExecutionException"));
569 mg.add(LDC,"Jumped to invalid address");
570 mg.add(INVOKESPECIAL,new MethodRef(new Type.Object("org.ibex.nestedvm.Runtime$ExecutionException"),"<init>",Type.VOID,new Type[]{Type.STRING}));
574 endOfMethod = startOfMethod = 0;
578 private void leaveMethod() {
579 mg.add(GOTO,returnTarget);
582 private void link(int mypc) {
585 int ref = (mypc+8 + 32768) & ~65535;
586 int diff = (mypc+8) - ref;
587 if(diff < -32768 || diff > 32767) throw new Error("should never happen " + diff);
597 private void branch(int pc, int target) {
598 if((pc&methodMask) == (target&methodMask)) {
599 mg.add(GOTO,insnTargets[(target-startOfMethod)/4]);
608 // This assumes everything needed by ifInsn is already on the stack
609 private int doIfInstruction(byte op, int pc, int target, int nextInsn) throws Exn {
610 emitInstruction(-1,nextInsn,-1); // delay slot
611 if((target&methodMask) == (pc&methodMask)) {
612 mg.add(op,insnTargets[(target-startOfMethod)/4]);
614 int h = mg.add(MethodGen.negate(op));
616 mg.setArg(h,mg.size());
618 if(!jumpable(pc+4)) return SKIP_NEXT; // done - skip it
620 //System.err.println("Delay slot is jumpable - This code is untested + " + toHex(nextInsn));
621 if(pc+4==endOfMethod) {
622 // the delay slot is at the start of the next method
623 jumpableAddresses.put(new Integer(pc+8),Boolean.TRUE); // make the 2nd insn of the next method jumpable
624 branch(pc,pc+8); // jump over it
625 //System.err.println("delay slot: " + toHex(pc+8)); */
626 //unreachable = true;
627 //return false; // we still need to output it
630 //System.err.println("jumped over delay slot: " + toHex(pc+4));
631 // add another copy and jump over
633 int b = mg.add(GOTO);
634 insnTargets[(pc+4-startOfMethod)/4].setTarget(mg.size());
635 emitInstruction(-1,nextInsn,01); // delay slot
636 mg.setArg(b,mg.size());
642 private static final Float POINT_5_F = new Float(0.5f);
643 private static final Double POINT_5_D = new Double(0.5f);
644 private static final Long FFFFFFFF = new Long(0xffffffffL);
646 private int emitInstruction(int pc, int insn, int nextInsn) throws Exn {
647 MethodGen mg = this.mg; // smaller bytecode
648 if(insn == -1) throw new Exn("insn is -1");
652 int op = (insn >>> 26) & 0xff; // bits 26-31
653 int rs = (insn >>> 21) & 0x1f; // bits 21-25
654 int rt = (insn >>> 16) & 0x1f; // bits 16-20
655 int ft = (insn >>> 16) & 0x1f;
656 int rd = (insn >>> 11) & 0x1f; // bits 11-15
657 int fs = (insn >>> 11) & 0x1f;
658 int shamt = (insn >>> 6) & 0x1f; // bits 6-10
659 int fd = (insn >>> 6) & 0x1f;
660 int subcode = insn & 0x3f; // bits 0-5
661 int breakCode = (insn >>> 6) & 0xfffff; // bits 6-20
663 int jumpTarget = (insn & 0x03ffffff); // bits 0-25
664 int unsignedImmediate = insn & 0xffff;
665 int signedImmediate = (insn << 16) >> 16;
666 int branchTarget = signedImmediate;
718 if(pc == -1) throw new Exn("pc modifying insn in delay slot");
719 emitInstruction(-1,nextInsn,-1);
727 if(pc == -1) throw new Exn("pc modifying insn in delay slot");
728 emitInstruction(-1,nextInsn,-1);
741 // FEATURE: This is actually broken, but it happens to work for our code
742 // a func could theoretically jump back to here from a future point
743 restoreChangedRegs();
754 mg.add(INVOKEVIRTUAL,new MethodRef(me,"syscall",Type.INT,new Type[]{Type.INT,Type.INT,Type.INT,Type.INT,Type.INT,Type.INT,Type.INT}));
758 mg.add(GETFIELD,new FieldRef(me,"state",Type.INT));
764 mg.setArg(b1,mg.size());
767 mg.add(NEW,new Type.Object("org.ibex.nestedvm.Runtime$ExecutionException"));
769 mg.add(LDC,"BREAK Code " + toHex(breakCode));
770 mg.add(INVOKESPECIAL,new MethodRef(new Type.Object("org.ibex.nestedvm.Runtime$ExecutionException"),"<init>",Type.VOID,new Type[]{Type.STRING}));
804 mg.add(SWAP); //a(InstructionConstants.SWAP);
811 mg.add(SWAP); //a(InstructionConstants.SWAP);
818 mg.add(LDC,FFFFFFFF);
822 mg.add(LDC,FFFFFFFF);
864 mg.add(LDC,FFFFFFFF);
869 mg.add(LDC,FFFFFFFF);
886 mg.setArg(b1,mg.size());
891 throw new Exn("ADD (add with oveflow trap) not suported");
894 if(rt != 0 && rs != 0) {
906 throw new Exn("SUB (add with oveflow trap) not suported");
909 if(rt != 0 && rs != 0) {
944 if(rs != 0 || rt != 0) {
945 if(rs != 0 && rt != 0) {
966 b1 = mg.add(IF_ICMPLT);
969 mg.setArg(b1,mg.add(ICONST_1));
970 mg.setArg(b2,mg.size());
982 mg.add(LDC,FFFFFFFF);
986 mg.add(LDC,FFFFFFFF);
996 mg.setArg(b1,mg.add(ICONST_1));
997 mg.setArg(b2,mg.size());
1004 throw new Exn("Illegal instruction 0/" + subcode);
1011 if(pc == -1) throw new Exn("pc modifying insn in delay slot");
1013 return doIfInstruction(IFLT,pc,pc+branchTarget*4+4,nextInsn);
1015 if(pc == -1) throw new Exn("pc modifying insn in delay slot");
1017 return doIfInstruction(IFGE,pc,pc+branchTarget*4+4,nextInsn);
1019 if(pc == -1) throw new Exn("pc modifying insn in delay slot");
1022 emitInstruction(-1,nextInsn,-1);
1024 branch(pc,pc+branchTarget*4+4);
1025 mg.setArg(b1,mg.size());
1028 if(pc == -1) throw new Exn("pc modifying insn in delay slot");
1030 if(rs != 0) { // r0 is always >= 0
1034 emitInstruction(-1,nextInsn,-1);
1036 branch(pc,pc+branchTarget*4+4);
1037 if(b1 != -1) mg.setArg(b1,mg.size());
1038 if(b1 == -1) ret |= UNREACHABLE;
1041 throw new Exn("Illegal Instruction 1/" + rt);
1046 if(pc == -1) throw new Exn("pc modifying insn in delay slot");
1047 emitInstruction(-1,nextInsn,-1);
1048 branch(pc,(pc&0xf0000000)|(jumpTarget << 2));
1053 if(pc == -1) throw new Exn("pc modifying insn in delay slot");
1054 int target = (pc&0xf0000000)|(jumpTarget << 2);
1055 emitInstruction(-1,nextInsn,-1);
1062 if(pc == -1) throw new Exn("pc modifying insn in delay slot");
1064 emitInstruction(-1,nextInsn,-1);
1065 branch(pc,pc+branchTarget*4+4);
1067 } else if(rs == 0 || rt == 0) {
1068 pushReg(rt == 0 ? R+rs : R+rt);
1069 return doIfInstruction(IFEQ,pc,pc+branchTarget*4+4,nextInsn);
1073 return doIfInstruction(IF_ICMPEQ,pc,pc+branchTarget*4+4,nextInsn);
1077 if(pc == -1) throw new Exn("pc modifying insn in delay slot");
1080 return doIfInstruction(IFNE,pc,pc+branchTarget*4+4,nextInsn);
1083 return doIfInstruction(IF_ICMPNE,pc,pc+branchTarget*4+4,nextInsn);
1086 if(pc == -1) throw new Exn("pc modifying insn in delay slot");
1088 return doIfInstruction(IFLE,pc,pc+branchTarget*4+4,nextInsn);
1090 if(pc == -1) throw new Exn("pc modifying insn in delay slot");
1092 return doIfInstruction(IFGT,pc,pc+branchTarget*4+4,nextInsn);
1094 throw new Exn("ADDI (add immediate with oveflow trap) not suported");
1096 if(rs != 0 && signedImmediate != 0 && rs == rt && doLocal(rt) && signedImmediate >= -32768 && signedImmediate <= 32767) {
1097 // HACK: This should be a little cleaner
1098 regLocalWritten[rt] = true;
1099 mg.add(IINC, new MethodGen.Pair(getLocalForReg(rt),signedImmediate));
1102 addiu(rs,signedImmediate);
1109 mg.add(LDC,signedImmediate);
1110 b1 = mg.add(IF_ICMPLT);
1113 mg.setArg(b1,mg.add(ICONST_1));
1114 mg.setArg(b2,mg.size());
1121 mg.add(LDC,FFFFFFFF);
1123 // Yes, this is correct, you have to sign extend the immediate then do an UNSIGNED comparison
1124 mg.add(LDC,new Long(signedImmediate&0xffffffffL));
1130 mg.setArg(b1,mg.add(ICONST_1));
1131 mg.setArg(b2,mg.size());
1137 mg.add(LDC,unsignedImmediate);
1143 if(rs != 0 && unsignedImmediate != 0) {
1145 mg.add(LDC,unsignedImmediate);
1150 mg.add(LDC,unsignedImmediate);
1157 mg.add(LDC,unsignedImmediate);
1163 mg.add(LDC,unsignedImmediate << 16);
1167 throw new Exn("TLB/Exception support not implemented");
1176 if(fs != 31) throw new Exn("FCR " + fs + " unavailable");
1183 if(rt != 0) pushReg(R+rt);
1184 else mg.add(ICONST_0);
1188 if(fs != 31) throw new Exn("FCR " + fs + " unavailable");
1193 case 8: {// BC1F, BC1T
1195 mg.add(LDC,0x800000);
1197 return doIfInstruction(((insn>>>16)&1) == 0 ? IFEQ : IFNE,pc,pc+branchTarget*4+4,nextInsn);
1201 { // Single/Double math
1202 boolean d = rs == 17;
1205 preSetDouble(F+fd,d);
1208 mg.add(d ? DADD : FADD);
1212 preSetDouble(F+fd,d);
1215 mg.add(d ? DSUB : FSUB);
1219 preSetDouble(F+fd,d);
1222 mg.add(d ? DMUL : FMUL);
1226 preSetDouble(F+fd,d);
1229 mg.add(d ? DDIV : FDIV);
1233 preSetDouble(F+fd,d);
1234 // NOTE: We can't use fneg/dneg here since they'll turn +0.0 into -0.0
1237 mg.add(d ? DUP2 : DUP);
1238 mg.add(d ? DCONST_0 : FCONST_0);
1239 mg.add(d ? DCMPG : FCMPG);
1242 mg.add(d ? DCONST_0 : FCONST_0);
1249 mg.add(d ? DSUB : FSUB);
1251 mg.setArg(b1,mg.size());
1267 preSetDouble(F+fd,d);
1269 mg.add(d ? DNEG : FNEG);
1284 case 36: { // CVT.W.D
1285 MethodGen.TSI tsi = new MethodGen.TSI(0,3);
1291 mg.add(TABLESWITCH,tsi);
1293 // Round towards plus infinity
1294 tsi.setTarget(2,mg.size());
1295 if(!d) mg.add(F2D); // Ugh.. java.lang.Math doesn't have a float ceil/floor
1296 mg.add(INVOKESTATIC,new MethodRef("java.lang.Math","ceil",Type.DOUBLE,new Type[]{Type.DOUBLE}));
1301 tsi.setTarget(0,mg.size());
1302 mg.add(LDC,d ? (Object)POINT_5_D : (Object)POINT_5_F);
1303 mg.add(d ? DADD : FADD);
1306 // Round towards minus infinity
1307 tsi.setTarget(3,mg.size());
1309 mg.add(INVOKESTATIC,new MethodRef("java.lang.Math","floor",Type.DOUBLE,new Type[]{Type.DOUBLE}));
1312 tsi.setTarget(1,mg.size());
1313 tsi.setDefaultTarget(mg.size());
1314 mg.setArg(b1,mg.size());
1316 mg.add(d ? D2I : F2I);
1326 mg.add(LDC,~0x800000);
1330 mg.add(d ? DCMPG : FCMPG);
1332 case 50: b1 = mg.add(IFNE); break;
1333 case 60: b1 = mg.add(IFGE); break;
1334 case 62: b1 = mg.add(IFGT); break;
1337 mg.add(LDC,0x800000);
1339 mg.setArg(b1,mg.size());
1342 default: throw new Exn("Invalid Instruction 17/" + rs + "/" + subcode);
1346 case 20: { // Integer
1360 default: throw new Exn("Invalid Instruction 17/" + rs + "/" + subcode);
1365 throw new Exn("Invalid Instruction 17/" + rs);
1370 throw new Exn("coprocessor 2 and 3 instructions not available");
1373 addiu(R+rs,signedImmediate);
1393 addiu(R+rs,signedImmediate);
1413 addiu(R+rs,signedImmediate);
1417 mg.add(LDC,0x00ffffff);
1448 memRead(R+rs,signedImmediate);
1453 addiu(R+rs,signedImmediate);
1474 addiu(R+rs,signedImmediate);
1489 // chars are unsigend so this works
1496 addiu(R+rs,signedImmediate);
1500 mg.add(LDC,0xffffff00);
1529 addiu(R+rs,signedImmediate);
1536 mg.add(LDC,0xff000000);
1571 addiu(R+rs,signedImmediate);
1611 addiu(R+rs,signedImmediate);
1618 mg.add(LDC,0xffffff00);
1646 preMemWrite2(R+rs,signedImmediate);
1651 addiu(R+rs,signedImmediate);
1658 mg.add(LDC,0x00ffffff);
1683 // This need to be atomic if we ever support threads (see SWC0/SC)
1686 memRead(R+rs,signedImmediate);
1692 memRead(R+rs,signedImmediate);
1696 /* This needs to fail (set rt to 0) if the memory location was modified
1697 * between the LL and SC if we ever support threads.
1702 preMemWrite2(R+rs,signedImmediate);
1711 preMemWrite2(R+rs,signedImmediate);
1716 throw new Exn("Invalid Instruction: " + op + " at " + toHex(pc));
1721 // Helper functions for emitText
1723 private static final int R = 0;
1724 private static final int F = 32;
1725 private static final int HI = 64;
1726 private static final int LO = 65;
1727 private static final int FCSR = 66;
1728 private static final int REG_COUNT=67;
1729 private static final String[] regField = {
1730 "r0","r1","r2","r3","r4","r5","r6","r7",
1731 "r8","r9","r10","r11","r12","r13","r14","r15",
1732 "r16","r17","r18","r19","r20","r21","r22","r23",
1733 "r24","r25","r26","r27","r28","r29","r30","r31",
1734 "f0","f1","f2","f3","f4","f5","f6","f7",
1735 "f8","f9","f10","f11","f12","f13","f14","f15",
1736 "f16","f17","f18","f19","f20","f21","f22","f23",
1737 "f24","f25","f26","f27","f28","f29","f30","f31",
1740 private static final int MAX_LOCALS = 4; // doLocal can return true for this many regs
1741 private static final int LOAD_LENGTH = 3; // number of instructions needed to load a field to a reg
1743 // Local register state info
1744 private int[] regLocalMapping = new int[REG_COUNT];
1745 private boolean[] regLocalWritten = new boolean[REG_COUNT];
1746 private int nextAvailLocal;
1747 private int loadsStart;
1749 private boolean doLocal(int reg) {
1750 return reg == R+2 || reg == R+3 || reg == R+4 || reg == R+29;
1753 private int getLocalForReg(int reg) {
1754 if(regLocalMapping[reg] != 0) return regLocalMapping[reg];
1755 regLocalMapping[reg] = nextAvailLocal++;
1756 return regLocalMapping[reg];
1759 private void fixupRegsStart() {
1760 for(int i=0;i<REG_COUNT;i++) {
1761 regLocalMapping[i] = 0;
1762 regLocalWritten[i] = false;
1764 nextAvailLocal = onePage ? 4 : 5;
1765 loadsStart = mg.size();
1766 for(int i=0;i<MAX_LOCALS*LOAD_LENGTH;i++)
1770 private void fixupRegsEnd() {
1772 for(int i=0;i<REG_COUNT;i++) {
1773 if(regLocalMapping[i] == 0) continue;
1774 mg.set(p++,ALOAD_0);
1775 mg.set(p++,GETFIELD,new FieldRef(me,regField[i],Type.INT));
1776 mg.set(p++,ISTORE,regLocalMapping[i]);
1778 if(regLocalWritten[i]) {
1780 mg.add(ILOAD,regLocalMapping[i]);
1781 mg.add(PUTFIELD,new FieldRef(me,regField[i],Type.INT));
1786 private void restoreChangedRegs() {
1787 for(int i=0;i<REG_COUNT;i++) {
1788 if(regLocalWritten[i]) {
1790 mg.add(ILOAD,regLocalMapping[i]);
1791 mg.add(PUTFIELD,new FieldRef(me,regField[i],Type.INT));
1796 private int pushRegWZ(int reg) {
1798 warn.println("Warning: Pushing r0!");
1799 new Exception().printStackTrace(warn);
1801 return pushRegZ(reg);
1804 private int pushRegZ(int reg) {
1805 if(reg == R+0) return mg.add(ICONST_0);
1806 else return pushReg(reg);
1810 private int pushReg(int reg) {
1813 mg.add(ILOAD,getLocalForReg(reg));
1814 } else if(reg >= F+0 && reg <= F+31 && singleFloat) {
1816 mg.add(GETFIELD,new FieldRef(me,regField[reg],Type.FLOAT));
1817 mg.add(INVOKESTATIC,new MethodRef(Type.FLOAT_OBJECT,"floatToIntBits",Type.INT,new Type[]{Type.FLOAT}));
1820 mg.add(GETFIELD,new FieldRef(me,regField[reg],Type.INT));
1825 private int preSetRegStackPos;
1826 private int[] preSetRegStack = new int[8];
1828 // This can push ONE or ZERO words to the stack. If it pushed one it returns true
1829 private boolean preSetReg(int reg) {
1830 preSetRegStack[preSetRegStackPos] = reg;
1831 preSetRegStackPos++;
1840 private int setReg() {
1841 if(preSetRegStackPos==0) throw new RuntimeException("didn't do preSetReg");
1842 preSetRegStackPos--;
1843 int reg = preSetRegStack[preSetRegStackPos];
1846 mg.add(ISTORE,getLocalForReg(reg));
1847 regLocalWritten[reg] = true;
1848 } else if(reg >= F+0 && reg <= F+31 && singleFloat) {
1849 mg.add(INVOKESTATIC,new MethodRef(Type.FLOAT_OBJECT,"intBitsToFloat",Type.FLOAT,new Type[]{Type.INT}));
1850 mg.add(PUTFIELD,new FieldRef(me,regField[reg],Type.FLOAT));
1852 mg.add(PUTFIELD,new FieldRef(me,regField[reg],Type.INT));
1857 private int preSetPC() { return mg.add(ALOAD_0); }
1858 private int setPC() {
1859 return mg.add(PUTFIELD,new FieldRef(me,"pc",Type.INT));
1862 //unused - private InstructionHandle pushDouble(int reg) throws CompilationException { return pushDouble(reg,true); }
1863 private int pushFloat(int reg) throws Exn { return pushDouble(reg,false); }
1864 private int pushDouble(int reg, boolean d) throws Exn {
1865 if(reg < F || reg >= F+32) throw new IllegalArgumentException(""+reg);
1868 if(singleFloat) throw new Exn("Double operations not supported when singleFloat is enabled");
1869 if(reg == F+31) throw new Exn("Tried to use a double in f31");
1876 mg.add(LDC,FFFFFFFF);
1879 mg.add(INVOKESTATIC,new MethodRef(Type.DOUBLE_OBJECT,"longBitsToDouble",Type.DOUBLE,new Type[]{Type.LONG}));
1880 } else if(singleFloat) {
1882 mg.add(GETFIELD,new FieldRef(me,regField[reg],Type.FLOAT));
1885 mg.add(INVOKESTATIC,new MethodRef("java.lang.Float","intBitsToFloat",Type.FLOAT,new Type[]{Type.INT}));
1890 private void preSetFloat(int reg) { preSetDouble(reg,false); }
1891 private void preSetDouble(int reg) { preSetDouble(reg,true); }
1892 private void preSetDouble(int reg, boolean d) { preSetReg(reg); }
1894 private int setFloat() throws Exn { return setDouble(false); }
1895 private int setDouble() throws Exn { return setDouble(true); }
1896 private int setDouble(boolean d) throws Exn {
1897 int reg = preSetRegStack[preSetRegStackPos-1];
1898 if(reg < F || reg >= F+32) throw new IllegalArgumentException(""+reg);
1901 if(singleFloat) throw new Exn("Double operations not supported when singleFloat is enabled");
1902 if(reg == F+31) throw new Exn("Tried to use a double in f31");
1903 mg.add(INVOKESTATIC,new MethodRef(Type.DOUBLE_OBJECT,"doubleToLongBits",Type.LONG,new Type[]{Type.DOUBLE}));
1908 if(preSetReg(reg+1))
1912 setReg(); // preSetReg was already done for this by preSetDouble
1913 } else if(singleFloat) {
1914 // HACK: Clean this up
1915 preSetRegStackPos--;
1916 mg.add(PUTFIELD,new FieldRef(me,regField[reg],Type.FLOAT));
1918 //h = a(fac.createInvoke("java.lang.Float","floatToRawIntBits",Type.INT,new Type[]{Type.FLOAT},INVOKESTATIC));
1919 mg.add(INVOKESTATIC,new MethodRef(Type.FLOAT_OBJECT,"floatToRawIntBits",Type.INT,new Type[]{Type.FLOAT}));
1925 private void pushTmp() { mg.add(ILOAD_1); }
1926 private void setTmp() { mg.add(ISTORE_1); }
1928 private void addiu(int reg, int offset) {
1929 if(reg != R+0 && offset != 0) {
1933 } else if(reg != R+0) {
1939 private int memWriteStage;
1940 private void preMemWrite1() {
1941 if(memWriteStage!=0) throw new Error("pending preMemWrite1/2");
1951 private void preMemWrite2(int reg, int offset) {
1956 private void preMemWrite2() { preMemWrite2(false); }
1957 private void preMemWrite2(boolean addrInTmp) {
1958 if(memWriteStage!=1) throw new Error("pending preMemWrite2 or no preMemWrite1");
1961 if(nullPointerCheck) {
1965 mg.add(INVOKEVIRTUAL,new MethodRef(me,"nullPointerCheck",Type.VOID,new Type[]{Type.INT}));
1971 } else if(fastMem) {
1974 mg.add(LDC,pageShift);
1983 mg.add(LDC,(pageSize>>2)-1);
1988 // pops an address and value off the stack, sets *addr to value
1989 private void memWrite() {
1990 if(memWriteStage!=2) throw new Error("didn't do preMemWrite1 or preMemWrite2");
1995 } else if(fastMem) {
1998 mg.add(INVOKEVIRTUAL,new MethodRef(me,"unsafeMemWrite",Type.VOID,new Type[]{Type.INT,Type.INT}));
2003 // reads the word at r[reg]+offset
2004 private void memRead(int reg, int offset) {
2010 private boolean didPreMemRead;
2011 private boolean preMemReadDoPreWrite;
2013 private void preMemRead() { preMemRead(false); }
2014 private void preMemRead(boolean preWrite) {
2015 if(didPreMemRead) throw new Error("pending preMemRead");
2016 didPreMemRead = true;
2017 preMemReadDoPreWrite = preWrite;
2021 mg.add(ALOAD,preWrite ? 3 : 2);
2025 // memRead pops an address off the stack, reads the value at that addr, and pushed the value
2026 // preMemRead MUST be called BEFORE the addresses is pushed
2027 private void memRead() { memRead(false); }
2029 private void memRead(boolean addrInTmp) {
2030 if(!didPreMemRead) throw new Error("didn't do preMemRead");
2031 didPreMemRead = false;
2032 if(preMemReadDoPreWrite)
2035 if(nullPointerCheck) {
2039 mg.add(INVOKEVIRTUAL,new MethodRef(me,"nullPointerCheck",Type.VOID,new Type[]{Type.INT}));
2045 if(preMemReadDoPreWrite)
2048 } else if(fastMem) {
2051 mg.add(LDC,pageShift);
2060 mg.add(LDC,(pageSize>>2)-1);
2062 if(preMemReadDoPreWrite)
2067 if(preMemReadDoPreWrite)
2069 mg.add(INVOKEVIRTUAL,new MethodRef(me,"unsafeMemRead",Type.INT,new Type[]{Type.INT}));
2074 // This might come in handy for something else
2075 /*private boolean touchesReg(int insn, int reg) {
2076 if((reg < R+0 || reg >= R+32) && reg != FCSR) throw new IllegalArgumentException(""+reg);
2077 if(reg == R+0) return false; // r0 is never modified
2078 int op = (insn >>> 26) & 0xff; // bits 26-31
2079 int subcode = insn & 0x3f; // bits 0-5
2080 int rd = (insn >>> 11) & 0x1f; // bits 11-15
2081 int rt = (insn >>> 16) & 0x1f; // bits 16-20
2082 int rs = (insn >>> 21) & 0x1f; // bits 21-25
2086 if(subcode >= 0 && subcode <= 7) return reg == R+rd; // Shift ops
2087 if(subcode >= 32 && subcode <= 43) return reg == R+rd; // Other math ops
2088 if(subcode >= 24 && subcode <= 27) return reg == HI || reg == LO; // MULT/DIV
2090 case 13: return false; // BREAK
2093 case 0: return reg == R+rt; // MFC.1
2094 case 2: return reg == R+rt; // CFC.1
2095 case 4: return false; // MTC.1
2096 case 6: return false; // CTC.1
2099 if(subcode == 50 || subcode == 60 || subcode == 62) return reg == FCSR;
2100 return false; // everything else just touches f0-f31
2101 case 20: return false; // Integer - just touches f0-f31
2105 if(op >= 8 && op <= 15) return reg == R+rt; // XXXI instructions
2106 if(op >= 40 && op <= 46) return false; // Memory WRITE ops
2107 if(op == 49) return reg == F+rt; // LWC1
2108 if(op == 57) return false; // SWC1
2111 warn.println("Unknown instruction in touchesReg()- assuming it modifies all regs " + op + " " + subcode);
2112 new Exception().fillInStackTrace().printStackTrace(warn);