1 // Copyright 2003 Brian Alliet
2 // Based on org.xwt.imp.MIPS by Adam Megacz
3 // Portions Copyright 2003 Adam Megacz
5 package org.ibex.nestedvm;
7 import org.ibex.nestedvm.util.*;
9 import java.util.Arrays;
11 public abstract class Runtime implements UsermodeConstants,Registers,Cloneable {
12 public static final String VERSION = "1.0";
14 /** True to write useful diagnostic information to stderr when things go wrong */
15 final static boolean STDERR_DIAG = true;
17 /** Number of bits to shift to get the page number (1<<<pageShift == pageSize) */
18 protected final int pageShift;
19 /** Bottom of region of memory allocated to the stack */
20 private final int stackBottom;
22 /** Readable main memory pages */
23 protected int[][] readPages;
24 /** Writable main memory pages.
25 If the page is writable writePages[x] == readPages[x]; if not writePages[x] == null. */
26 protected int[][] writePages;
28 /** The address of the end of the heap */
31 /** Number of guard pages to keep between the stack and the heap */
32 private static final int STACK_GUARD_PAGES = 4;
34 /** The last address the executable uses (other than the heap/stack) */
35 protected abstract int heapStart();
37 /** The program's entry point */
38 protected abstract int entryPoint();
40 /** The location of the _user_info block (or 0 is there is none) */
41 protected int userInfoBase() { return 0; }
42 protected int userInfoSize() { return 0; }
44 /** The location of the global pointer */
45 protected abstract int gp();
47 /** When the process started */
48 private long startTime;
50 /** Text/Data loaded in memory */
51 public final static int STOPPED = 0;
52 /** Program is executing instructions */
53 public final static int RUNNING = 1;
54 /** Prgram has been started but is paused */
55 public final static int PAUSED = 2;
56 /** Program is executing a callJava() method */
57 public final static int CALLJAVA = 3;
58 /** Program has exited (it cannot currently be restarted) */
59 public final static int EXITED = 4;
60 /** Program has executed a successful exec(), a new Runtime needs to be run (used by UnixRuntime) */
61 public final static int EXECED = 5;
63 /** The current state */
64 protected int state = STOPPED;
65 /** @see Runtime#state state */
66 public final int getState() { return state; }
68 /** The exit status if the process (only valid if state==DONE)
70 private int exitStatus;
71 public ExecutionException exitException;
73 /** Table containing all open file descriptors. (Entries are null if the fd is not in use */
74 FD[] fds = new FD[OPEN_MAX]; // package-private for UnixRuntime
75 boolean closeOnExec[] = new boolean[OPEN_MAX];
77 /** Pointer to a SecurityManager for this process */
79 public void setSecurityManager(SecurityManager sm) { this.sm = sm; }
81 /** Pointer to a callback for the call_java syscall */
82 private CallJavaCB callJavaCB;
83 public void setCallJavaCB(CallJavaCB callJavaCB) { this.callJavaCB = callJavaCB; }
85 /** Temporary buffer for read/write operations */
86 private byte[] _byteBuf;
87 /** Max size of temporary buffer
88 @see Runtime#_byteBuf */
89 final static int MAX_CHUNK = 16*1024*1024 - 1024;
91 /** Subclasses should actually execute program in this method. They should continue
92 executing until state != RUNNING. Only syscall() can modify state. It is safe
93 to only check the state attribute after a call to syscall() */
94 protected abstract void _execute() throws ExecutionException;
96 /** Subclasses should return the address of the symbol <i>symbol</i> or -1 it it doesn't exits in this method
97 This method is only required if the call() function is used */
98 protected int lookupSymbol(String symbol) { return -1; }
100 /** Subclasses should populate a CPUState object representing the cpu state */
101 protected abstract void getCPUState(CPUState state);
103 /** Subclasses should set the CPUState to the state held in <i>state</i> */
104 protected abstract void setCPUState(CPUState state);
106 protected Object clone() throws CloneNotSupportedException {
107 Runtime r = (Runtime) super.clone();
110 r.fds = new FD[OPEN_MAX];
111 for(int i=0;i<OPEN_MAX;i++) if(fds[i] != null) r.fds[i] = fds[i].dup();
112 int totalPages = writePages.length;
113 r.readPages = new int[totalPages][];
114 r.writePages = new int[totalPages][];
115 for(int i=0;i<totalPages;i++) {
116 if(readPages[i] == null) continue;
117 if(writePages[i] == null) r.readPages[i] = readPages[i];
118 else r.readPages[i] = r.writePages[i] = (int[])writePages[i].clone();
123 protected Runtime(int pageSize, int totalPages) {
124 if(pageSize <= 0) throw new IllegalArgumentException("pageSize <= 0");
125 if(totalPages <= 0) throw new IllegalArgumentException("totalPages <= 0");
126 if((pageSize&(pageSize-1)) != 0) throw new IllegalArgumentException("pageSize not a power of two");
129 while(pageSize>>>_pageShift != 1) _pageShift++;
130 pageShift = _pageShift;
132 int heapStart = heapStart();
133 int totalMemory = totalPages * pageSize;
134 int stackSize = max(totalMemory/512,ARG_MAX+65536);
137 stackSize = max(stackSize,pageSize);
138 stackSize = (stackSize + pageSize - 1) & ~(pageSize-1);
139 stackPages = stackSize >>> pageShift;
140 heapStart = (heapStart + pageSize - 1) & ~(pageSize-1);
141 if(stackPages + STACK_GUARD_PAGES + (heapStart >>> pageShift) >= totalPages)
142 throw new IllegalArgumentException("total pages too small");
144 if(pageSize < heapStart + stackSize) throw new IllegalArgumentException("total memory too small");
145 heapStart = (heapStart + 4095) & ~4096;
148 stackBottom = totalMemory - stackSize;
151 readPages = new int[totalPages][];
152 writePages = new int[totalPages][];
154 if(totalPages == 1) {
155 readPages[0] = writePages[0] = new int[pageSize>>2];
157 for(int i=(stackBottom >>> pageShift);i<writePages.length;i++) {
158 readPages[i] = writePages[i] = new int[pageSize>>2];
162 InputStream stdin = Boolean.valueOf(getSystemProperty("nestedvm.textstdin")).booleanValue() ? new TextInputStream(System.in) : System.in;
163 addFD(new TerminalFD(stdin));
164 addFD(new TerminalFD(System.out));
165 addFD(new TerminalFD(System.err));
168 /** Copy everything from <i>src</i> to <i>addr</i> initializing uninitialized pages if required.
169 Newly initalized pages will be marked read-only if <i>ro</i> is set */
170 protected final void initPages(int[] src, int addr, boolean ro) {
171 int pageWords = (1<<pageShift)>>>2;
172 int pageMask = (1<<pageShift) - 1;
174 for(int i=0;i<src.length;) {
175 int page = addr >>> pageShift;
176 int start = (addr&pageMask)>>2;
177 int elements = min(pageWords-start,src.length-i);
178 if(readPages[page]==null) {
181 if(writePages[page] == null) writePages[page] = readPages[page];
183 System.arraycopy(src,i,readPages[page],start,elements);
189 /** Initialize <i>words</i> of pages starting at <i>addr</i> to 0 */
190 protected final void clearPages(int addr, int words) {
191 int pageWords = (1<<pageShift)>>>2;
192 int pageMask = (1<<pageShift) - 1;
194 for(int i=0;i<words;) {
195 int page = addr >>> pageShift;
196 int start = (addr&pageMask)>>2;
197 int elements = min(pageWords-start,words-i);
198 if(readPages[page]==null) {
199 readPages[page] = writePages[page] = new int[pageWords];
201 if(writePages[page] == null) writePages[page] = readPages[page];
202 for(int j=start;j<start+elements;j++) writePages[page][j] = 0;
209 /** Copies <i>length</i> bytes from the processes memory space starting at
210 <i>addr</i> INTO a java byte array <i>a</i> */
211 public final void copyin(int addr, byte[] buf, int count) throws ReadFaultException {
212 int pageWords = (1<<pageShift)>>>2;
213 int pageMask = pageWords - 1;
216 if(count == 0) return;
218 int word = memRead(addr&~3);
220 case 1: buf[x++] = (byte)((word>>>16)&0xff); if(--count==0) break;
221 case 2: buf[x++] = (byte)((word>>> 8)&0xff); if(--count==0) break;
222 case 3: buf[x++] = (byte)((word>>> 0)&0xff); if(--count==0) break;
226 if((count&~3) != 0) {
230 int[] page = readPages[a >>> (pageShift-2)];
231 if(page == null) throw new ReadFaultException(a<<2);
232 int index = a&pageMask;
233 int n = min(c,pageWords-index);
234 for(int i=0;i<n;i++,x+=4) {
235 int word = page[index+i];
236 buf[x+0] = (byte)((word>>>24)&0xff); buf[x+1] = (byte)((word>>>16)&0xff);
237 buf[x+2] = (byte)((word>>> 8)&0xff); buf[x+3] = (byte)((word>>> 0)&0xff);
241 addr = a<<2; count &=3;
244 int word = memRead(addr);
246 case 3: buf[x+2] = (byte)((word>>>8)&0xff);
247 case 2: buf[x+1] = (byte)((word>>>16)&0xff);
248 case 1: buf[x+0] = (byte)((word>>>24)&0xff);
253 /** Copies <i>length</i> bytes OUT OF the java array <i>a</i> into the processes memory
254 space at <i>addr</i> */
255 public final void copyout(byte[] buf, int addr, int count) throws FaultException {
256 int pageWords = (1<<pageShift)>>>2;
257 int pageWordMask = pageWords - 1;
260 if(count == 0) return;
262 int word = memRead(addr&~3);
264 case 1: word = (word&0xff00ffff)|((buf[x++]&0xff)<<16); if(--count==0) break;
265 case 2: word = (word&0xffff00ff)|((buf[x++]&0xff)<< 8); if(--count==0) break;
266 case 3: word = (word&0xffffff00)|((buf[x++]&0xff)<< 0); if(--count==0) break;
268 memWrite(addr&~3,word);
272 if((count&~3) != 0) {
276 int[] page = writePages[a >>> (pageShift-2)];
277 if(page == null) throw new WriteFaultException(a<<2);
278 int index = a&pageWordMask;
279 int n = min(c,pageWords-index);
280 for(int i=0;i<n;i++,x+=4)
281 page[index+i] = ((buf[x+0]&0xff)<<24)|((buf[x+1]&0xff)<<16)|((buf[x+2]&0xff)<<8)|((buf[x+3]&0xff)<<0);
284 addr = a<<2; count&=3;
288 int word = memRead(addr);
290 case 1: word = (word&0x00ffffff)|((buf[x+0]&0xff)<<24); break;
291 case 2: word = (word&0x0000ffff)|((buf[x+0]&0xff)<<24)|((buf[x+1]&0xff)<<16); break;
292 case 3: word = (word&0x000000ff)|((buf[x+0]&0xff)<<24)|((buf[x+1]&0xff)<<16)|((buf[x+2]&0xff)<<8); break;
298 public final void memcpy(int dst, int src, int count) throws FaultException {
299 int pageWords = (1<<pageShift)>>>2;
300 int pageWordMask = pageWords - 1;
301 if((dst&3) == 0 && (src&3)==0) {
302 if((count&~3) != 0) {
307 int[] srcPage = readPages[s>>>(pageShift-2)];
308 if(srcPage == null) throw new ReadFaultException(s<<2);
309 int[] dstPage = writePages[d>>>(pageShift-2)];
310 if(dstPage == null) throw new WriteFaultException(d<<2);
311 int srcIndex = s&pageWordMask;
312 int dstIndex = d&pageWordMask;
313 int n = min(c,pageWords-max(srcIndex,dstIndex));
314 System.arraycopy(srcPage,srcIndex,dstPage,dstIndex,n);
315 s += n; d += n; c -= n;
317 src = s<<2; dst = d<<2; count&=3;
320 int word1 = memRead(src);
321 int word2 = memRead(dst);
323 case 1: memWrite(dst,(word1&0xff000000)|(word2&0x00ffffff)); break;
324 case 2: memWrite(dst,(word1&0xffff0000)|(word2&0x0000ffff)); break;
325 case 3: memWrite(dst,(word1&0xffffff00)|(word2&0x000000ff)); break;
330 int n = min(count,MAX_CHUNK);
331 byte[] buf = byteBuf(n);
334 count -= n; src += n; dst += n;
339 public final void memset(int addr, int ch, int count) throws FaultException {
340 int pageWords = (1<<pageShift)>>>2;
341 int pageWordMask = pageWords - 1;
343 int fourBytes = ((ch&0xff)<<24)|((ch&0xff)<<16)|((ch&0xff)<<8)|((ch&0xff)<<0);
345 int word = memRead(addr&~3);
347 case 1: word = (word&0xff00ffff)|((ch&0xff)<<16); if(--count==0) break;
348 case 2: word = (word&0xffff00ff)|((ch&0xff)<< 8); if(--count==0) break;
349 case 3: word = (word&0xffffff00)|((ch&0xff)<< 0); if(--count==0) break;
351 memWrite(addr&~3,word);
354 if((count&~3) != 0) {
358 int[] page = readPages[a>>>(pageShift-2)];
359 if(page == null) throw new WriteFaultException(a<<2);
360 int index = a&pageWordMask;
361 int n = min(c,pageWords-index);
362 Arrays.fill(page,index,index+n,fourBytes);
365 addr = a<<2; count&=3;
368 int word = memRead(addr);
370 case 1: word = (word&0x00ffffff)|(fourBytes&0xff000000); break;
371 case 2: word = (word&0x0000ffff)|(fourBytes&0xffff0000); break;
372 case 3: word = (word&0x000000ff)|(fourBytes&0xffffff00); break;
378 /** Read a word from the processes memory at <i>addr</i> */
379 public final int memRead(int addr) throws ReadFaultException {
380 if((addr & 3) != 0) throw new ReadFaultException(addr);
381 return unsafeMemRead(addr);
384 protected final int unsafeMemRead(int addr) throws ReadFaultException {
385 int page = addr >>> pageShift;
386 int entry = (addr&(1<<pageShift) - 1)>>2;
388 return readPages[page][entry];
389 } catch(ArrayIndexOutOfBoundsException e) {
390 if(page < 0 || page >= readPages.length) throw new ReadFaultException(addr);
391 throw e; // should never happen
392 } catch(NullPointerException e) {
393 throw new ReadFaultException(addr);
397 /** Writes a word to the processes memory at <i>addr</i> */
398 public final void memWrite(int addr, int value) throws WriteFaultException {
399 if((addr & 3) != 0) throw new WriteFaultException(addr);
400 unsafeMemWrite(addr,value);
403 protected final void unsafeMemWrite(int addr, int value) throws WriteFaultException {
404 int page = addr >>> pageShift;
405 int entry = (addr&(1<<pageShift) - 1)>>2;
407 writePages[page][entry] = value;
408 } catch(ArrayIndexOutOfBoundsException e) {
409 if(page < 0 || page >= writePages.length) throw new WriteFaultException(addr);
410 throw e; // should never happen
411 } catch(NullPointerException e) {
412 throw new WriteFaultException(addr);
416 /** Created a new non-empty writable page at page number <i>page</i> */
417 private final int[] initPage(int page) { return initPage(page,false); }
418 /** Created a new non-empty page at page number <i>page</i>. If <i>ro</i> is set the page will be read-only */
419 private final int[] initPage(int page, boolean ro) {
420 int[] buf = new int[(1<<pageShift)>>>2];
421 writePages[page] = ro ? null : buf;
422 readPages[page] = buf;
426 /** Returns the exit status of the process. (only valid if state == DONE)
427 @see Runtime#state */
428 public final int exitStatus() {
429 if(state != EXITED) throw new IllegalStateException("exitStatus() called in an inappropriate state");
433 private int addStringArray(String[] strings, int topAddr) throws FaultException {
434 int count = strings.length;
435 int total = 0; /* null last table entry */
436 for(int i=0;i<count;i++) total += strings[i].length() + 1;
437 total += (count+1)*4;
438 int start = (topAddr - total)&~3;
439 int addr = start + (count+1)*4;
440 int[] table = new int[count+1];
442 for(int i=0;i<count;i++) {
443 byte[] a = getBytes(strings[i]);
445 copyout(a,addr,a.length);
446 memset(addr+a.length,0,1);
447 addr += a.length + 1;
450 for(int i=0;i<count+1;i++) {
451 memWrite(addr,table[i]);
454 } catch(FaultException e) {
455 throw new RuntimeException(e.toString());
460 String[] createEnv(String[] extra) { if(extra == null) extra = new String[0]; return extra; }
462 /** Sets word number <i>index</i> in the _user_info table to <i>word</i>
463 * The user_info table is a chunk of memory in the program's memory defined by the
464 * symbol "user_info". The compiler/interpreter automatically determine the size
465 * and location of the user_info table from the ELF symbol table. setUserInfo and
466 * getUserInfo are used to modify the words in the user_info table. */
467 public void setUserInfo(int index, int word) {
468 if(index < 0 || index >= userInfoSize()/4) throw new IndexOutOfBoundsException("setUserInfo called with index >= " + (userInfoSize()/4));
470 memWrite(userInfoBase()+index*4,word);
471 } catch(FaultException e) { throw new RuntimeException(e.toString()); }
474 /** Returns the word in the _user_info table entry <i>index</i>
475 @see Runtime#setUserInfo(int,int) setUserInfo */
476 public int getUserInfo(int index) {
477 if(index < 0 || index >= userInfoSize()/4) throw new IndexOutOfBoundsException("setUserInfo called with index >= " + (userInfoSize()/4));
479 return memRead(userInfoBase()+index*4);
480 } catch(FaultException e) { throw new RuntimeException(e.toString()); }
483 /** Calls _execute() (subclass's execute()) and catches exceptions */
484 // FEATURE: Have these call kill() so we get a pretty message to stdout
485 private void __execute() {
488 } catch(FaultException e) {
489 if(STDERR_DIAG) e.printStackTrace();
490 sys_exit(128+11); // SIGSEGV
492 } catch(ExecutionException e) {
493 if(STDERR_DIAG) e.printStackTrace();
494 sys_exit(128+4); // SIGILL
499 /** Executes the process until the PAUSE syscall is invoked or the process exits. Returns true if the process exited. */
500 public final boolean execute() {
501 if(state != PAUSED) throw new IllegalStateException("execute() called in inappropriate state");
502 if(startTime == 0) startTime = System.currentTimeMillis();
505 if(state != PAUSED && state != EXITED && state != EXECED)
506 throw new IllegalStateException("execute() ended up in an inappropriate state (" + state + ")");
507 return state != PAUSED;
510 static String[] concatArgv(String argv0, String[] rest) {
511 String[] argv = new String[rest.length+1];
512 System.arraycopy(rest,0,argv,1,rest.length);
517 public final int run() { return run(null); }
518 public final int run(String argv0, String[] rest) { return run(concatArgv(argv0,rest)); }
519 public final int run(String[] args) { return run(args,null); }
521 /** Runs the process until it exits and returns the exit status.
522 If the process executes the PAUSE syscall execution will be paused for 500ms and a warning will be displayed */
523 public final int run(String[] args, String[] env) {
527 if(STDERR_DIAG) System.err.println("WARNING: Pause requested while executing run()");
529 if(state == EXECED && STDERR_DIAG) System.err.println("WARNING: Process exec()ed while being run under run()");
530 return state == EXITED ? exitStatus() : 0;
533 public final void start() { start(null); }
534 public final void start(String[] args) { start(args,null); }
536 /** Initializes the process and prepairs it to be executed with execute() */
537 public final void start(String[] args, String[] environ) {
538 int top, sp, argsAddr, envAddr;
539 if(state != STOPPED) throw new IllegalStateException("start() called in inappropriate state");
541 if(args == null) args = new String[]{getClass().getName()};
543 sp = top = writePages.length*(1<<pageShift);
545 sp = argsAddr = addStringArray(args,sp);
546 sp = envAddr = addStringArray(createEnv(environ),sp);
547 } catch(FaultException e) {
548 throw new IllegalArgumentException("args/environ too big");
551 if(top - sp > ARG_MAX) throw new IllegalArgumentException("args/environ too big");
553 // HACK: heapStart() isn't always available when the constructor
554 // is run and this sometimes doesn't get initialized
556 heapEnd = heapStart();
557 if(heapEnd == 0) throw new Error("heapEnd == 0");
558 int pageSize = writePages.length == 1 ? 4096 : (1<<pageShift);
559 heapEnd = (heapEnd + pageSize - 1) & ~(pageSize-1);
562 CPUState cpuState = new CPUState();
563 cpuState.r[A0] = argsAddr;
564 cpuState.r[A1] = envAddr;
566 cpuState.r[RA] = 0xdeadbeef;
567 cpuState.r[GP] = gp();
568 cpuState.pc = entryPoint();
569 setCPUState(cpuState);
576 /** Hook for subclasses to do their own startup */
579 public final int call(String sym, Object[] args) throws CallException, FaultException {
580 if(state != PAUSED && state != CALLJAVA) throw new IllegalStateException("call() called in inappropriate state");
581 if(args.length > 7) throw new IllegalArgumentException("args.length > 7");
582 CPUState state = new CPUState();
585 int sp = state.r[SP];
586 int[] ia = new int[args.length];
587 for(int i=0;i<args.length;i++) {
590 if(o instanceof String) {
591 buf = getBytes((String)o);
592 } else if(o instanceof byte[]) {
594 } else if(o instanceof Number) {
595 ia[i] = ((Number)o).intValue();
599 copyout(buf,sp,buf.length);
603 int oldSP = state.r[SP];
604 if(oldSP == sp) return call(sym,ia);
608 int ret = call(sym,ia);
614 public final int call(String sym) throws CallException { return call(sym,new int[]{}); }
615 public final int call(String sym, int a0) throws CallException { return call(sym,new int[]{a0}); }
616 public final int call(String sym, int a0, int a1) throws CallException { return call(sym,new int[]{a0,a1}); }
618 /** Calls a function in the process with the given arguments */
619 public final int call(String sym, int[] args) throws CallException {
620 int func = lookupSymbol(sym);
621 if(func == -1) throw new CallException(sym + " not found");
622 int helper = lookupSymbol("_call_helper");
623 if(helper == -1) throw new CallException("_call_helper not found");
624 return call(helper,func,args);
627 /** Executes the code at <i>addr</i> in the process setting A0-A3 and S0-S3 to the given arguments
628 and returns the contents of V1 when the the pause syscall is invoked */
629 //public final int call(int addr, int a0, int a1, int a2, int a3, int s0, int s1, int s2, int s3) {
630 public final int call(int addr, int a0, int[] rest) throws CallException {
631 if(rest.length > 7) throw new IllegalArgumentException("rest.length > 7");
632 if(state != PAUSED && state != CALLJAVA) throw new IllegalStateException("call() called in inappropriate state");
633 int oldState = state;
634 CPUState saved = new CPUState();
636 CPUState cpustate = saved.dup();
638 cpustate.r[SP] = cpustate.r[SP]&~15;
639 cpustate.r[RA] = 0xdeadbeef;
641 switch(rest.length) {
642 case 7: cpustate.r[S3] = rest[6];
643 case 6: cpustate.r[S2] = rest[5];
644 case 5: cpustate.r[S1] = rest[4];
645 case 4: cpustate.r[S0] = rest[3];
646 case 3: cpustate.r[A3] = rest[2];
647 case 2: cpustate.r[A2] = rest[1];
648 case 1: cpustate.r[A1] = rest[0];
654 setCPUState(cpustate);
656 getCPUState(cpustate);
659 if(state != PAUSED) throw new CallException("Process exit()ed while servicing a call() request");
662 return cpustate.r[V1];
665 /** Allocated an entry in the FileDescriptor table for <i>fd</i> and returns the number.
666 Returns -1 if the table is full. This can be used by subclasses to use custom file
668 public final int addFD(FD fd) {
669 if(state == EXITED || state == EXECED) throw new IllegalStateException("addFD called in inappropriate state");
671 for(i=0;i<OPEN_MAX;i++) if(fds[i] == null) break;
672 if(i==OPEN_MAX) return -1;
674 closeOnExec[i] = false;
678 /** Closes file descriptor <i>fdn</i> and removes it from the file descriptor table */
679 public final boolean closeFD(int fdn) {
680 if(state == EXITED || state == EXECED) throw new IllegalStateException("closeFD called in inappropriate state");
681 if(fdn < 0 || fdn >= OPEN_MAX) return false;
682 if(fds[fdn] == null) return false;
688 /** Duplicates the file descriptor <i>fdn</i> and returns the new fs */
689 public final int dupFD(int fdn) {
691 if(fdn < 0 || fdn >= OPEN_MAX) return -1;
692 if(fds[fdn] == null) return -1;
693 for(i=0;i<OPEN_MAX;i++) if(fds[i] == null) break;
694 if(i==OPEN_MAX) return -1;
695 fds[i] = fds[fdn].dup();
699 public static final int RD_ONLY = 0;
700 public static final int WR_ONLY = 1;
701 public static final int RDWR = 2;
703 public static final int O_CREAT = 0x0200;
704 public static final int O_EXCL = 0x0800;
705 public static final int O_APPEND = 0x0008;
706 public static final int O_TRUNC = 0x0400;
707 public static final int O_NONBLOCK = 0x4000;
708 public static final int O_NOCTTY = 0x8000;
711 FD hostFSOpen(final File f, int flags, int mode, final Object data) throws ErrnoException {
712 if((flags & ~(3|O_CREAT|O_EXCL|O_APPEND|O_TRUNC)) != 0) {
714 System.err.println("WARNING: Unsupported flags passed to open(\"" + f + "\"): " + toHex(flags & ~(3|O_CREAT|O_EXCL|O_APPEND|O_TRUNC)));
716 throw new ErrnoException(ENOTSUP);
718 boolean write = (flags&3) != RD_ONLY;
720 if(sm != null && !(write ? sm.allowWrite(f) : sm.allowRead(f))) throw new ErrnoException(EACCES);
722 if((flags & (O_EXCL|O_CREAT)) == (O_EXCL|O_CREAT)) {
724 // NOTE: createNewFile is a Java2 function
725 if(!f.createNewFile()) throw new ErrnoException(EEXIST);
726 } catch(IOException e) {
727 throw new ErrnoException(EIO);
729 } else if(!f.exists()) {
730 if((flags&O_CREAT)==0) return null;
731 } else if(f.isDirectory()) {
732 return hostFSDirFD(f,data);
736 final Seekable.File sf;
738 sf = new Seekable.File(f,write);
739 } catch(FileNotFoundException e) {
740 if(e.getMessage() != null && e.getMessage().indexOf("Permission denied") >= 0) throw new ErrnoException(EACCES);
742 } catch(IOException e) { throw new ErrnoException(EIO); }
744 return new SeekableFD(sf,flags) { protected FStat _fstat() { return hostFStat(f,data); } };
747 FStat hostFStat(File f, Object data) { return new HostFStat(f); }
749 FD hostFSDirFD(File f, Object data) { return null; }
751 FD _open(String path, int flags, int mode) throws ErrnoException {
752 return hostFSOpen(new File(path),flags,mode,null);
755 /** The open syscall */
756 private int sys_open(int addr, int flags, int mode) throws ErrnoException, FaultException {
757 flags &= ~O_NOCTTY; // this is meaningless under nestedvm
758 FD fd = _open(cstring(addr),flags,mode);
759 if(fd == null) return -ENOENT;
761 if(fdn == -1) { fd.close(); return -ENFILE; }
765 /** The write syscall */
767 private int sys_write(int fdn, int addr, int count) throws FaultException, ErrnoException {
768 count = Math.min(count,MAX_CHUNK);
769 if(fdn < 0 || fdn >= OPEN_MAX) return -EBADFD;
770 if(fds[fdn] == null) return -EBADFD;
771 byte[] buf = byteBuf(count);
772 copyin(addr,buf,count);
774 return fds[fdn].write(buf,0,count);
775 } catch(ErrnoException e) {
776 if(e.errno == EPIPE) sys_exit(128+13);
781 /** The read syscall */
782 private int sys_read(int fdn, int addr, int count) throws FaultException, ErrnoException {
783 count = Math.min(count,MAX_CHUNK);
784 if(fdn < 0 || fdn >= OPEN_MAX) return -EBADFD;
785 if(fds[fdn] == null) return -EBADFD;
786 byte[] buf = byteBuf(count);
787 int n = fds[fdn].read(buf,0,count);
792 /** The close syscall */
793 private int sys_close(int fdn) {
794 return closeFD(fdn) ? 0 : -EBADFD;
798 /** The seek syscall */
799 private int sys_lseek(int fdn, int offset, int whence) throws ErrnoException {
800 if(fdn < 0 || fdn >= OPEN_MAX) return -EBADFD;
801 if(fds[fdn] == null) return -EBADFD;
802 if(whence != SEEK_SET && whence != SEEK_CUR && whence != SEEK_END) return -EINVAL;
803 int n = fds[fdn].seek(offset,whence);
804 return n < 0 ? -ESPIPE : n;
807 /** The stat/fstat syscall helper */
808 // FIXME: Populate uid/gid/nlink
809 int stat(FStat fs, int addr) throws FaultException {
810 memWrite(addr+0,(fs.dev()<<16)|(fs.inode()&0xffff)); // st_dev (top 16), // st_ino (bottom 16)
811 memWrite(addr+4,((fs.type()&0xf000))|(fs.mode()&0xfff)); // st_mode
812 memWrite(addr+8,1<<16); // st_nlink (top 16) // st_uid (bottom 16)
813 memWrite(addr+12,0); // st_gid (top 16) // st_rdev (bottom 16)
814 memWrite(addr+16,fs.size()); // st_size
815 memWrite(addr+20,fs.atime()); // st_atime
816 // memWrite(addr+24,0) // st_spare1
817 memWrite(addr+28,fs.mtime()); // st_mtime
818 // memWrite(addr+32,0) // st_spare2
819 memWrite(addr+36,fs.ctime()); // st_ctime
820 // memWrite(addr+40,0) // st_spare3
821 memWrite(addr+44,fs.blksize()); // st_bklsize;
822 memWrite(addr+48,fs.blocks()); // st_blocks
823 // memWrite(addr+52,0) // st_spare4[0]
824 // memWrite(addr+56,0) // st_spare4[1]
828 /** The fstat syscall */
829 private int sys_fstat(int fdn, int addr) throws FaultException {
830 if(fdn < 0 || fdn >= OPEN_MAX) return -EBADFD;
831 if(fds[fdn] == null) return -EBADFD;
832 return stat(fds[fdn].fstat(),addr);
841 private int sys_gettimeofday(int timevalAddr, int timezoneAddr) throws FaultException {
842 long now = System.currentTimeMillis();
843 int tv_sec = (int)(now / 1000);
844 int tv_usec = (int)((now%1000)*1000);
845 memWrite(timevalAddr+0,tv_sec);
846 memWrite(timevalAddr+4,tv_usec);
850 private int sys_sleep(int sec) {
851 if(sec < 0) sec = Integer.MAX_VALUE;
853 Thread.sleep((long)sec*1000);
855 } catch(InterruptedException e) {
861 #define _CLOCKS_PER_SEC_ 1000
862 #define _CLOCK_T_ unsigned long
870 private int sys_times(int tms) {
871 long now = System.currentTimeMillis();
872 int userTime = (int)((now - startTime)/16);
873 int sysTime = (int)((now - startTime)/16);
877 memWrite(tms+0,userTime);
878 memWrite(tms+4,sysTime);
879 memWrite(tms+8,userTime);
880 memWrite(tms+12,sysTime);
882 } catch(FaultException e) {
888 private int sys_sysconf(int n) {
890 case _SC_CLK_TCK: return 1000;
891 case _SC_PAGESIZE: return writePages.length == 1 ? 4096 : (1<<pageShift);
892 case _SC_PHYS_PAGES: return writePages.length == 1 ? (1<<pageShift)/4096 : writePages.length;
894 if(STDERR_DIAG) System.err.println("WARNING: Attempted to use unknown sysconf key: " + n);
899 /** The sbrk syscall. This can also be used by subclasses to allocate memory.
900 <i>incr</i> is how much to increase the break by */
901 public final int sbrk(int incr) {
902 if(incr < 0) return -ENOMEM;
903 if(incr==0) return heapEnd;
905 int oldEnd = heapEnd;
906 int newEnd = oldEnd + incr;
907 if(newEnd >= stackBottom) return -ENOMEM;
909 if(writePages.length > 1) {
910 int pageMask = (1<<pageShift) - 1;
911 int pageWords = (1<<pageShift) >>> 2;
912 int start = (oldEnd + pageMask) >>> pageShift;
913 int end = (newEnd + pageMask) >>> pageShift;
915 for(int i=start;i<end;i++) readPages[i] = writePages[i] = new int[pageWords];
916 } catch(OutOfMemoryError e) {
917 if(STDERR_DIAG) System.err.println("WARNING: Caught OOM Exception in sbrk: " + e);
925 /** The getpid syscall */
926 private int sys_getpid() { return getPid(); }
927 int getPid() { return 1; }
929 public static interface CallJavaCB { public int call(int a, int b, int c, int d); }
931 private int sys_calljava(int a, int b, int c, int d) {
932 if(state != RUNNING) throw new IllegalStateException("wound up calling sys_calljava while not in RUNNING");
933 if(callJavaCB != null) {
937 ret = callJavaCB.call(a,b,c,d);
938 } catch(RuntimeException e) {
939 System.err.println("Error while executing callJavaCB");
946 if(STDERR_DIAG) System.err.println("WARNING: calljava syscall invoked without a calljava callback set");
951 private int sys_pause() {
956 private int sys_getpagesize() { return writePages.length == 1 ? 4096 : (1<<pageShift); }
958 /** Hook for subclasses to do something when the process exits */
961 private int sys_exit(int status) {
963 for(int i=0;i<fds.length;i++) if(fds[i] != null) closeFD(i);
969 private int sys_fcntl(int fdn, int cmd, int arg) {
972 if(fdn < 0 || fdn >= OPEN_MAX) return -EBADFD;
973 if(fds[fdn] == null) return -EBADFD;
978 if(arg < 0 || arg >= OPEN_MAX) return -EINVAL;
979 for(i=arg;i<OPEN_MAX;i++) if(fds[i]==null) break;
980 if(i==OPEN_MAX) return -EMFILE;
986 closeOnExec[fdn] = arg != 0;
989 return closeOnExec[fdn] ? 1 : 0;
991 if(STDERR_DIAG) System.err.println("WARNING: Unknown fcntl command: " + cmd);
996 /** The syscall dispatcher.
997 The should be called by subclasses when the syscall instruction is invoked.
998 <i>syscall</i> should be the contents of V0 and <i>a</i>, <i>b</i>, <i>c</i>, and <i>d</i> should be
999 the contenst of A0, A1, A2, and A3. The call MAY change the state
1000 @see Runtime#state state */
1001 protected final int syscall(int syscall, int a, int b, int c, int d, int e, int f) {
1003 int n = _syscall(syscall,a,b,c,d,e,f);
1004 //if(n < 0) System.err.println("syscall: " + syscall + " returned " + n);
1006 } catch(ErrnoException ex) {
1007 //ex.printStackTrace();
1009 } catch(FaultException ex) {
1011 } catch(RuntimeException ex) {
1012 ex.printStackTrace();
1013 throw new Error("Internal Error in _syscall()");
1017 int _syscall(int syscall, int a, int b, int c, int d, int e, int f) throws ErrnoException, FaultException {
1019 case SYS_null: return 0;
1020 case SYS_exit: return sys_exit(a);
1021 case SYS_pause: return sys_pause();
1022 case SYS_write: return sys_write(a,b,c);
1023 case SYS_fstat: return sys_fstat(a,b);
1024 case SYS_sbrk: return sbrk(a);
1025 case SYS_open: return sys_open(a,b,c);
1026 case SYS_close: return sys_close(a);
1027 case SYS_read: return sys_read(a,b,c);
1028 case SYS_lseek: return sys_lseek(a,b,c);
1029 case SYS_getpid: return sys_getpid();
1030 case SYS_calljava: return sys_calljava(a,b,c,d);
1031 case SYS_gettimeofday: return sys_gettimeofday(a,b);
1032 case SYS_sleep: return sys_sleep(a);
1033 case SYS_times: return sys_times(a);
1034 case SYS_getpagesize: return sys_getpagesize();
1035 case SYS_fcntl: return sys_fcntl(a,b,c);
1036 case SYS_sysconf: return sys_sysconf(a);
1038 case SYS_memcpy: memcpy(a,b,c); return a;
1039 case SYS_memset: memset(a,b,c); return a;
1050 if(STDERR_DIAG) System.err.println("Attempted to use a UnixRuntime syscall in Runtime (" + syscall + ")");
1053 if(STDERR_DIAG) System.err.println("Attempted to use unknown syscall: " + syscall);
1058 public int xmalloc(int size) { int p=malloc(size); if(p==0) throw new RuntimeException("malloc() failed"); return p; }
1059 public int xrealloc(int addr,int newsize) { int p=realloc(addr,newsize); if(p==0) throw new RuntimeException("realloc() failed"); return p; }
1060 public int realloc(int addr, int newsize) { try { return call("realloc",addr,newsize); } catch(CallException e) { return 0; } }
1061 public int malloc(int size) { try { return call("malloc",size); } catch(CallException e) { return 0; } }
1062 public void free(int p) { try { if(p!=0) call("free",p); } catch(CallException e) { /*noop*/ } }
1064 /** Helper function to create a cstring in main memory */
1065 public int strdup(String s) {
1067 if(s == null) s = "(null)";
1068 byte[] a2 = getBytes(s);
1069 a = new byte[a2.length+1];
1070 System.arraycopy(a2,0,a,0,a2.length);
1071 int addr = malloc(a.length);
1072 if(addr == 0) return 0;
1074 copyout(a,addr,a.length);
1075 } catch(FaultException e) {
1082 /** Helper function to read a cstring from main memory */
1083 public final String cstring(int addr) throws ReadFaultException {
1084 StringBuffer sb = new StringBuffer();
1086 int word = memRead(addr&~3);
1088 case 0: if(((word>>>24)&0xff)==0) return sb.toString(); sb.append((char)((word>>>24)&0xff)); addr++;
1089 case 1: if(((word>>>16)&0xff)==0) return sb.toString(); sb.append((char)((word>>>16)&0xff)); addr++;
1090 case 2: if(((word>>> 8)&0xff)==0) return sb.toString(); sb.append((char)((word>>> 8)&0xff)); addr++;
1091 case 3: if(((word>>> 0)&0xff)==0) return sb.toString(); sb.append((char)((word>>> 0)&0xff)); addr++;
1096 /** File Descriptor class */
1097 public static abstract class FD {
1098 private int refCount = 1;
1100 /** Read some bytes. Should return the number of bytes read, 0 on EOF, or throw an IOException on error */
1101 public int read(byte[] a, int off, int length) throws ErrnoException { throw new ErrnoException(EBADFD); }
1102 /** Write. Should return the number of bytes written or throw an IOException on error */
1103 public int write(byte[] a, int off, int length) throws ErrnoException { throw new ErrnoException(EBADFD); }
1105 /** Seek in the filedescriptor. Whence is SEEK_SET, SEEK_CUR, or SEEK_END. Should return -1 on error or the new position. */
1106 public int seek(int n, int whence) throws ErrnoException { return -1; }
1108 public int getdents(byte[] a, int off, int length) throws ErrnoException { throw new ErrnoException(EBADFD); }
1110 public int flags() { return O_RDONLY; }
1112 /** Return a Seekable object representing this file descriptor (can be read only)
1113 This is required for exec() */
1114 Seekable seekable() { return null; }
1116 private FStat cachedFStat = null;
1117 public final FStat fstat() {
1118 if(cachedFStat == null) cachedFStat = _fstat();
1122 protected abstract FStat _fstat();
1124 /** Closes the fd */
1125 public final void close() { if(--refCount==0) _close(); }
1126 protected void _close() { /* noop*/ }
1128 FD dup() { refCount++; return this; }
1131 /** FileDescriptor class for normal files */
1132 public abstract static class SeekableFD extends FD {
1133 private final int flags;
1134 private final Seekable data;
1136 SeekableFD(Seekable data, int flags) { this.data = data; this.flags = flags; }
1138 protected abstract FStat _fstat();
1139 public int flags() { return flags; }
1141 Seekable seekable() { return data; }
1143 public int seek(int n, int whence) throws ErrnoException {
1146 case SEEK_SET: break;
1147 case SEEK_CUR: n += data.pos(); break;
1148 case SEEK_END: n += data.length(); break;
1153 } catch(IOException e) {
1154 throw new ErrnoException(ESPIPE);
1158 public int write(byte[] a, int off, int length) throws ErrnoException {
1159 if((flags&3) == RD_ONLY) throw new ErrnoException(EBADFD);
1160 // NOTE: There is race condition here but we can't fix it in pure java
1161 if((flags&O_APPEND) != 0) seek(0,SEEK_END);
1163 return data.write(a,off,length);
1164 } catch(IOException e) {
1165 throw new ErrnoException(EIO);
1169 public int read(byte[] a, int off, int length) throws ErrnoException {
1170 if((flags&3) == WR_ONLY) throw new ErrnoException(EBADFD);
1172 int n = data.read(a,off,length);
1173 return n < 0 ? 0 : n;
1174 } catch(IOException e) {
1175 throw new ErrnoException(EIO);
1179 protected void _close() { try { data.close(); } catch(IOException e) { /*ignore*/ } }
1182 public static class InputOutputStreamFD extends FD {
1183 private final InputStream is;
1184 private final OutputStream os;
1186 public InputOutputStreamFD(InputStream is) { this(is,null); }
1187 public InputOutputStreamFD(OutputStream os) { this(null,os); }
1188 public InputOutputStreamFD(InputStream is, OutputStream os) {
1191 if(is == null && os == null) throw new IllegalArgumentException("at least one stream must be supplied");
1194 public int flags() {
1195 if(is != null && os != null) return O_RDWR;
1196 if(is != null) return O_RDONLY;
1197 if(os != null) return O_WRONLY;
1198 throw new Error("should never happen");
1201 public void _close() {
1202 if(is != null) try { is.close(); } catch(IOException e) { /*ignore*/ }
1203 if(os != null) try { os.close(); } catch(IOException e) { /*ignore*/ }
1206 public int read(byte[] a, int off, int length) throws ErrnoException {
1207 if(is == null) return super.read(a,off,length);
1209 int n = is.read(a,off,length);
1210 return n < 0 ? 0 : n;
1211 } catch(IOException e) {
1212 throw new ErrnoException(EIO);
1216 public int write(byte[] a, int off, int length) throws ErrnoException {
1217 if(os == null) return super.write(a,off,length);
1219 os.write(a,off,length);
1221 } catch(IOException e) {
1222 throw new ErrnoException(EIO);
1226 public FStat _fstat() { return new FStat(); }
1229 static class TerminalFD extends InputOutputStreamFD {
1230 public TerminalFD(InputStream is) { this(is,null); }
1231 public TerminalFD(OutputStream os) { this(null,os); }
1232 public TerminalFD(InputStream is, OutputStream os) { super(is,os); }
1233 public void _close() { /* noop */ }
1234 public FStat _fstat() { return new FStat() { public int type() { return S_IFCHR; } }; }
1237 // FEATURE: TextInputStream: This is pretty inefficient but it is only used for reading from the console on win32
1238 static class TextInputStream extends InputStream {
1239 private int pushedBack = -1;
1240 private final InputStream parent;
1241 public TextInputStream(InputStream parent) { this.parent = parent; }
1242 public int read() throws IOException {
1243 if(pushedBack != -1) { int c = pushedBack; pushedBack = -1; return c; }
1244 int c = parent.read();
1245 if(c == '\r' && (c = parent.read()) != '\n') { pushedBack = c; return '\r'; }
1248 public int read(byte[] buf, int pos, int len) throws IOException {
1250 if(pushedBack != -1 && len > 0) {
1251 buf[0] = (byte) pushedBack;
1253 pos++; len--; pb = true;
1255 int n = parent.read(buf,pos,len);
1256 if(n == -1) return -1;
1257 for(int i=0;i<n;i++) {
1258 if(buf[pos+i] == '\r') {
1260 int c = parent.read();
1261 if(c == '\n') buf[pos+i] = '\n';
1262 else pushedBack = c;
1263 } else if(buf[pos+i+1] == '\n') {
1264 System.arraycopy(buf,pos+i+1,buf,pos+i,len-i-1);
1269 return n + (pb ? 1 : 0);
1273 public static class FStat {
1274 public static final int S_IFIFO = 0010000;
1275 public static final int S_IFCHR = 0020000;
1276 public static final int S_IFDIR = 0040000;
1277 public static final int S_IFREG = 0100000;
1279 public int dev() { return 1; }
1280 public int inode() { return hashCode() & 0x7fff; }
1281 public int mode() { return 0; }
1282 public int type() { return S_IFIFO; }
1283 public int nlink() { return 0; }
1284 public int uid() { return 0; }
1285 public int gid() { return 0; }
1286 public int size() { return 0; }
1287 public int atime() { return 0; }
1288 public int mtime() { return 0; }
1289 public int ctime() { return 0; }
1290 public int blksize() { return 512; }
1291 public int blocks() { return (size()+blksize()-1)/blksize(); }
1294 static class HostFStat extends FStat {
1295 private final File f;
1296 private final boolean executable;
1297 public HostFStat(File f) { this(f,false); }
1298 public HostFStat(File f, boolean executable) {
1300 this.executable = executable;
1302 public int dev() { return 1; }
1303 public int inode() { return f.getName().hashCode() & 0xffff; }
1304 public int type() { return f.isDirectory() ? S_IFDIR : S_IFREG; }
1305 public int nlink() { return 1; }
1308 boolean canread = f.canRead();
1309 if(canread && (executable || f.isDirectory())) mode |= 0111;
1310 if(canread) mode |= 0444;
1311 if(f.canWrite()) mode |= 0222;
1314 public int size() { return (int) f.length(); }
1315 public int mtime() { return (int)(f.lastModified()/1000); }
1319 public static class ReadFaultException extends FaultException {
1320 public ReadFaultException(int addr) { super(addr); }
1322 public static class WriteFaultException extends FaultException {
1323 public WriteFaultException(int addr) { super(addr); }
1325 public static class FaultException extends ExecutionException {
1326 public final int addr;
1327 public final RuntimeException cause;
1328 public FaultException(int addr) { super("fault at: " + toHex(addr)); this.addr = addr; cause = null; }
1329 public FaultException(RuntimeException e) { super(e.toString()); addr = -1; cause = e; }
1331 public static class ExecutionException extends Exception {
1332 private String message = "(null)";
1333 private String location = "(unknown)";
1334 public ExecutionException() { /* noop */ }
1335 public ExecutionException(String s) { if(s != null) message = s; }
1336 void setLocation(String s) { location = s == null ? "(unknown)" : s; }
1337 public final String getMessage() { return message + " at " + location; }
1339 public static class CallException extends Exception {
1340 public CallException(String s) { super(s); }
1343 protected static class ErrnoException extends Exception {
1345 public ErrnoException(int errno) { super("Errno: " + errno); this.errno = errno; }
1349 protected static class CPUState {
1350 public CPUState() { /* noop */ }
1352 public int[] r = new int[32];
1353 /* Floating point regs */
1354 public int[] f = new int[32];
1359 public CPUState dup() {
1360 CPUState c = new CPUState();
1365 for(int i=0;i<32;i++) {
1373 public static class SecurityManager {
1374 public boolean allowRead(File f) { return true; }
1375 public boolean allowWrite(File f) { return true; }
1376 public boolean allowStat(File f) { return true; }
1377 public boolean allowUnlink(File f) { return true; }
1380 // Null pointer check helper function
1381 protected final void nullPointerCheck(int addr) throws ExecutionException {
1383 throw new ExecutionException("Attempted to dereference a null pointer " + toHex(addr));
1386 // Utility functions
1387 byte[] byteBuf(int size) {
1388 if(_byteBuf==null) _byteBuf = new byte[size];
1389 else if(_byteBuf.length < size)
1390 _byteBuf = new byte[min(max(_byteBuf.length*2,size),MAX_CHUNK)];
1394 static String getSystemProperty(String key) {
1396 return System.getProperty(key);
1397 } catch(SecurityException e) {
1402 /** Decode a packed string */
1403 protected static final int[] decodeData(String s, int words) {
1404 if(s.length() % 8 != 0) throw new IllegalArgumentException("string length must be a multiple of 8");
1405 if((s.length() / 8) * 7 < words*4) throw new IllegalArgumentException("string isn't big enough");
1406 int[] buf = new int[words];
1407 int prev = 0, left=0;
1408 for(int i=0,n=0;n<words;i+=8) {
1410 for(int j=0;j<8;j++) { l <<= 7; l |= s.charAt(i+j) & 0x7f; }
1411 if(left > 0) buf[n++] = prev | (int)(l>>>(56-left));
1412 if(n < words) buf[n++] = (int) (l >>> (24-left));
1413 left = (left + 8) & 0x1f;
1414 prev = (int)(l << left);
1419 static byte[] getBytes(String s) {
1421 return s.getBytes("ISO-8859-1");
1422 } catch(UnsupportedEncodingException e) {
1423 return null; // should never happen
1427 static byte[] getNullTerminatedBytes(String s) {
1428 byte[] buf1 = getBytes(s);
1429 byte[] buf2 = new byte[buf1.length+1];
1430 System.arraycopy(buf1,0,buf2,0,buf1.length);
1434 final static String toHex(int n) { return "0x" + Long.toString(n & 0xffffffffL, 16); }
1435 final static int min(int a, int b) { return a < b ? a : b; }
1436 final static int max(int a, int b) { return a > b ? a : b; }