-abstract class MIPSEmu implements Syscalls, Errno {
- // Register Names
- protected final static int ZERO = 0; // Immutable, hardwired to 0
- protected final static int AT = 1; // Reserved for assembler
- protected final static int K0 = 26; // Reserved for kernel
- protected final static int K1 = 27; // Reserved for kernel
- protected final static int GP = 28; // Global pointer (the middle of .sdata/.sbss)
- protected final static int SP = 29; // Stack pointer
- protected final static int FP = 30; // Frame Pointer
- protected final static int RA = 31; // Return Address
-
- // Return values (caller saved)
- protected final static int V0 = 2;
- protected final static int V1 = 3;
- // Argument Registers (caller saved)
- protected final static int A0 = 4;
- protected final static int A1 = 5;
- protected final static int A2 = 6;
- protected final static int A3 = 7;
- // Temporaries (caller saved)
- protected final static int T0 = 8;
- protected final static int T1 = 9;
- protected final static int T2 = 10;
- protected final static int T3 = 11;
- protected final static int T4 = 12;
- protected final static int T5 = 13;
- protected final static int T6 = 14;
- protected final static int T7 = 15;
- protected final static int T8 = 24;
- protected final static int T9 = 25;
- // Saved (callee saved)
- protected final static int S0 = 16;
- protected final static int S1 = 17;
- protected final static int S2 = 18;
- protected final static int S3 = 19;
- protected final static int S4 = 20;
- protected final static int S5 = 21;
- protected final static int S6 = 22;
- protected final static int S7 = 23;
-
- // Page Constants
- // Page Size: 4k
- // Total Pages: 64k
- // Maxiumum Addressable memory 256mb
- // 1mb of stack space
- protected final static int PAGE_SIZE = 4096;
- protected final static int PAGE_WORDS = (int)(PAGE_SIZE >>> 2);
- protected final static int PAGE_SHIFT = 12;
- protected final static int STACK_PAGES = 256;
- // NOTE: If you change TOTAL_PAGES crt0.c needs to be updated to reflect the
- // new location of INITIAL_SP
- protected final static int TOTAL_PAGES = 65536;
- protected final static int BRK_LIMIT = 32768;
- // Top page is always empty
- // next page down contains command line arguments
- protected final static int ARGS_ADDR = (TOTAL_PAGES-2)*PAGE_SIZE;
- // next page down contains _user_info data
- protected final static int USER_INFO_ADDR = (TOTAL_PAGES-3)*PAGE_SIZE;
- // next page down is the start of the stack
- protected final static int INITIAL_SP = (TOTAL_PAGES-3)*PAGE_SIZE;
- // magic page that signified an allocated but empty (untouched) page
- private final static int[] emptyPage = new int[0];
-
- // Main memory
- protected final int[][] readPages;
- protected final int[][] writePages;
-
- // Brk
- protected int brk; // PAGE not address
-
- // Entry point - what start() sets pc to
- protected int entryPoint;
-
- // State constants
- public final static int UNINITIALIZED = 0;
- public final static int INITIALIZED = 1;
- public final static int RUNNING = 2;
- public final static int PAUSED = 3;
- public final static int DONE = 4;
-
- // State
- protected int state = UNINITIALIZED;
- public final int getState() { return state; }
- protected int exitStatus;
-
- // File descriptors
- private final static int OPEN_MAX = 256;
- private FileDescriptor[] fds;
-
- // Temporary buffer for read/write operations
- private byte[] _byteBuf = null;
- private final static int MAX_CHUNK = 4*1024*1024-8;
-
- // Abstract methods
- // This should start executing at pc
- public abstract void execute() throws EmulationException;
- // This should initialize the cpu registers to point to the entry point
- protected abstract void _start(int pc);
-
- public static final int PID = 1;
-
- public MIPSEmu() {
- readPages = new int[TOTAL_PAGES][];
- writePages = new int[TOTAL_PAGES][];
- for(int i=0;i<STACK_PAGES;i++)
- readPages[TOTAL_PAGES-1-i] = writePages[TOTAL_PAGES-1-i] = emptyPage;
- }
-
- public void copyin(int addr, byte[] a, int length) throws ReadFaultException {
- int n=0;
- if((addr&3)!=0) {
- int word = memRead(addr&~3);
- switch(addr&3) {
- case 1: a[n++] = (byte)((word>>>16)&0xff); if(length-n==0) break;
- case 2: a[n++] = (byte)((word>>> 8)&0xff); if(length-n==0) break;
- case 3: a[n++] = (byte)((word>>> 0)&0xff); if(length-n==0) break;
- }
- addr = (addr&~3)+4;
- }
- while(length-n > 3) {
- int start = (addr&(PAGE_SIZE-1))>>2;
- int end = start + (min(PAGE_SIZE-(addr&(PAGE_SIZE-1)),(length-n)&~3) >> 2);
- int[] page = readPages[addr >>> PAGE_SHIFT];
- if(page == null) throw new ReadFaultException(addr);
- if(page == emptyPage) { addr+=(end-start); n+=(end-start); continue; }
- for(int i=start;i<end;i++,addr+=4) {
- int word = page[i];
- a[n++] = (byte)((word>>>24)&0xff); a[n++] = (byte)((word>>>16)&0xff);
- a[n++] = (byte)((word>>> 8)&0xff); a[n++] = (byte)((word>>> 0)&0xff);
- }
- }
- if(length-n > 0) {
- int word = memRead(addr);
- if(length-n >= 1) a[n] = (byte)((word>>>24)&0xff);
- if(length-n >= 2) a[n+1] = (byte)((word>>>16)&0xff);
- if(length-n >= 3) a[n+2] = (byte)((word>>> 8)&0xff);
- }
- }
-
- public void copyout(byte[] a, int addr, int length) throws FaultException {
- int n=0;
- if((addr&3)!=0) {
- int word = memRead(addr&~3);
- switch(addr&3) {
- case 1: word = (word&0xff00ffff)|((a[n]&0xff)<<16); n++; if(length-n==0) break;
- case 2: word = (word&0xffff00ff)|((a[n]&0xff)<< 8); n++; if(length-n==0) break;
- case 3: word = (word&0xffffff00)|((a[n]&0xff)<< 0); n++; if(length-n==0) break;
- }
- memWrite(addr&~3,word);
- addr = (addr&~3)+4;
- }
-
- while(length-n > 3) {
- int start = (addr&(PAGE_SIZE-1))>>2;
- int end = start + (min(PAGE_SIZE-(addr&(PAGE_SIZE-1)),(length-n)&~3) >> 2);
- int[] page = writePages[addr >>> PAGE_SHIFT];
- if(page == null) throw new WriteFaultException(addr);
- if(page == emptyPage) { memWrite(addr,0); page = writePages[addr >>> PAGE_SHIFT]; }
- for(int i=start;i<end;i++,addr+=4) {
- int word = ((a[n+0]&0xff)<<24)|((a[n+1]&0xff)<<16)|((a[n+2]&0xff)<<8)|((a[n+3]&0xff)<<0); n+=4;
- page[i] = word;
- }
- }
- if(length-n > 0) {
- int word = memRead(addr);
- word = (word&0x00ffffff)|((a[n]&0xff)<<24);
- if(length-n > 1) { word = (word&0xff00ffff)|((a[n+1]&0xff)<<16); }
- if(length-n > 2) { word = (word&0xffff00ff)|((a[n+2]&0xff)<< 8); }
- memWrite(addr,word);
- }
- }
-
- protected final int memRead(int addr) throws ReadFaultException {
- if((addr & 3) != 0) throw new ReadFaultException(addr);
- int page = addr >>> PAGE_SHIFT;
- int entry = (addr >>> 2) & (PAGE_WORDS-1);
- try {
- return readPages[page][entry];
- } catch(ArrayIndexOutOfBoundsException e) {
- if(page < 0) throw e; // should never happen
- if(page > readPages.length) throw new ReadFaultException(addr);
- if(readPages[page] != emptyPage) throw e; // should never happen
- initPage(page);
- return 0;
- } catch(NullPointerException e) {
- throw new ReadFaultException(addr);
- }
- }
-
- protected final void memWrite(int addr, int value) throws WriteFaultException {
- if((addr & 3) != 0) throw new WriteFaultException(addr);
- int page = addr >>> PAGE_SHIFT;
- int entry = (addr>>>2)&(PAGE_WORDS-1);
- try {
- writePages[page][entry] = value;
- } catch(ArrayIndexOutOfBoundsException e) {
- if(page < 0) throw e;// should never happen
- if(page > writePages.length) throw new WriteFaultException(addr);
- if(readPages[page] != emptyPage) throw e; // should never happen
- initPage(page);
- writePages[page][entry] = value;
- } catch(NullPointerException e) {
- throw new WriteFaultException(addr);
- }
- }
-
- protected void initPage(int page) { writePages[page] = readPages[page] = new int[PAGE_WORDS]; }
-
- public final int exitStatus() {
- if(state != DONE) throw new IllegalStateException("exitStatus() called in an inappropriate state");
- return exitStatus;
- }
-
- public final int run(String[] args) throws EmulationException {
- start(args);
- for(;;) {
- execute();
- if(state != PAUSED) break;
- System.err.println("WARNING: Pause requested while executing run()");
- try { Thread.sleep(500); } catch(InterruptedException e) { }
- }
- if(state != DONE) throw new IllegalStateException("run() ended up in an inappropriate state");
- return exitStatus();
- }
-
- private void addArgs(String[] args) throws EmulationException {
- if(state == UNINITIALIZED || state == RUNNING || state == PAUSED) throw new IllegalStateException("addArgs() called in inappropriate state");
- int count = args.length;
- byte[] nullTerminator = new byte[1];
- int total = 4; /* null last table entry */
- for(int i=0;i<count;i++) total += args[i].length() + 1/*null terminator*/ + 4/*table entry*/;
- if(total > PAGE_SIZE) throw new EmulationException("Arguments too large");
- int start = ARGS_ADDR;
- int addr = start + (count+1)*4;
- int[] table = new int[count+1];
- for(int i=0;i<count;i++) {
- byte[] a;
- try { a = args[i].getBytes("US-ASCII"); } catch(UnsupportedEncodingException e){ throw new Error(e.getMessage()); }
- table[i] = addr;
-
- copyout(a,addr,a.length);
- addr += a.length;
- copyout(nullTerminator,addr,1);
- addr += 1;
-
- }
- addr=start;
- for(int i=0;i<count;i++) {
- memWrite(addr,table[i]);
- addr += 4;
- }
- }
-
- public void setUserInfo(int index, int word) throws EmulationException {
- if(index < 0 || index >= 1024) throw new EmulationException("setUserInfo called with index >= 1024");
- memWrite(USER_INFO_ADDR+index*4,word);
- }
-
- public int getUserInfo(int index) throws EmulationException {
- if(index < 0 || index >= 1024) throw new EmulationException("getUserInfo called with index >= 1024");
- return memRead(USER_INFO_ADDR+index*4);
- }
-
- public final void start(String[] args) throws EmulationException {
- if(state == UNINITIALIZED || state == RUNNING || state == PAUSED) throw new IllegalStateException("start() called in inappropriate state");
- _start(entryPoint);
- addArgs(args);
- fds = new FileDescriptor[OPEN_MAX];
- fds[0] = new InputStreamFD(System.in) { public boolean isatty() { return true; } };
- fds[1] = new OutputStreamFD(System.out) { public boolean isatty() { return true; } };
- fds[2] = new OutputStreamFD(System.err) { public boolean isatty() { return true; } };
- state = PAUSED;
- }
-
-
- // Syscalls
- private int write(int fdn, int addr, int count) {
- int n = 0;
- int r;
- FileDescriptor fd;
- count = Math.min(count,MAX_CHUNK);
- try {
- fd = fds[fdn];
- if(fd == null || !fd.writable()) return -EBADFD;
- } catch(ArrayIndexOutOfBoundsException e) {
- return -EBADFD;
- }
- try {
- byte[] buf = byteBuf(count);
- copyin(addr,buf,count);
- return fd.write(buf,0,count);
- } catch(FaultException e) {
- System.err.println(e);
- return -EFAULT;
- } catch(IOException e) {
- System.err.println(e);
- return -EIO;
- }
- }
-
- private int read(int fdn, int addr, int count) {
- FileDescriptor fd;
- count = Math.min(count,MAX_CHUNK);
- try {
- fd = fds[fdn];
- if(fd == null || !fd.readable()) return -EBADFD;
- } catch(ArrayIndexOutOfBoundsException e) {
- return -EBADFD;
- }
- try {
- byte[] buf = byteBuf(count);
- int n = fd.read(buf,0,count);
- copyout(buf,addr,n);
- return n;
- } catch(FaultException e) {
- System.err.println(e);
- return -EFAULT;
- } catch(IOException e) {
- System.err.println(e);
- return -EIO;
- }
- }
-
- private int close(int fdn) {
- FileDescriptor fd;
- try {
- fd = fds[fdn];
- if(fd == null) return -EBADFD;
- } catch(ArrayIndexOutOfBoundsException e) {
- return -EBADFD;
- }
- fds[fdn] = null;
- fd.close();
- return 0;
- }
-
- private int stat(FileInfo fi, int addr) {
- int size = fi.size();
- try {
- memWrite(addr+0,0); // st_dev (top 16), // st_ino (bottom 16)
- memWrite(addr+4,(fi.type() & 0xf000)|0644); // st_mode
- memWrite(addr+8,1); // st_nlink (top 16) // st_uid (bottom 16)
- memWrite(addr+12,0); // st_gid (top 16) // st_rdev (bottom 16)
- memWrite(addr+16,size); // st_size
- memWrite(addr+20,0); // st_atime
- // memWrite(addr+24,0) // st_spare1
- memWrite(addr+28,(int)(fi.modTime()/1000)); // st_mtime
- // memWrite(addr+32,0) // st_spare2
- memWrite(addr+36,0); // st_atime
- // memWrite(addr+40,0) // st_spare3
- memWrite(addr+44,512); // st_bklsize;
- memWrite(addr+48,(size+511)&(~511)); // st_blocks
- // memWrite(addr+52,0) // st_spare4[0]
- // memWrite(addr+56,0) // st_spare4[1]
- } catch(FaultException e) {
- System.err.println(e);
- return -EFAULT;
- }
- return 0;
- }
-
- private int fstat(int fdn, int addr) {
- FileDescriptor fd;
- try {
- fd = fds[fdn];
- if(fd == null) return -EBADFD;
- } catch(ArrayIndexOutOfBoundsException e) {
- return -EBADFD;
- }
- return stat(fd.fileInfo(),addr);
- }
-
- public int sbrk(int incr) {
- if(incr==0) return brk<<PAGE_SHIFT;
- int oldBrk = brk;
- int newBrk = oldBrk + ((incr+PAGE_SIZE-1)>>PAGE_SHIFT);
- if(newBrk >= BRK_LIMIT) {
- System.err.println("Hit BRK_LIMIT");
- return -ENOMEM;
- }
- for(int i=oldBrk;i<newBrk+256;i++)
- readPages[i] = writePages[i] = emptyPage;
- brk = newBrk;
- return oldBrk<<PAGE_SHIFT;
- }
-
- private int open(int addr, int flags, int mode) {
- final int O_RDONLY = 0;
- final int O_WRONLY = 1;
- final int O_RDWR = 2;
- final int O_APPEND = 0x0008;
- final int O_CREAT = 0x0200;
- final int O_NONBLOCK = 0x4000;
- final int O_EXCL = 0x0800;
-
- if((flags & O_APPEND) != 0) {
- System.err.println("WARNING: O_APPEND not supported");
- return -EOPNOTSUPP;
- }
- if((flags & O_NONBLOCK) != 0) {
- System.err.println("WARNING: O_NONBLOCK not supported");
- return -EOPNOTSUPP;
- }
-
- try {
- int fdn=-1;
- File f = new File(cstring(addr));
- System.err.println("Opening: " + f);
- if((flags & O_EXCL) != 0 && (flags & O_CREAT) != 0)
- if(!f.createNewFile()) return -EEXIST;
- if(f.exists()) {
- if(f.length() >= Integer.MAX_VALUE) return -EOPNOTSUPP;
- } else {
- if((flags & O_CREAT) == 0) return -ENOENT;
- }
- for(int i=0;i<OPEN_MAX;i++) if(fds[i] == null) { fdn = i; break; }
- if(fdn==-1) return -ENFILE;
- fds[fdn] = new RegularFileDescriptor(f,flags&3);
- return fdn;
- } catch(FaultException e) {
- return -EFAULT;
- } catch(FileNotFoundException e) {
- if(e.getMessage().indexOf("Permission denied") >= 0) return -EACCES;
- return -ENOENT;
- } catch(IOException e) {
- return -EIO;
- }
- }
-
- private int seek(int fdn, int offset, int whence) {
- FileDescriptor fd;
- try {
- fd = fds[fdn];
- if(fd == null || !fd.readable()) return -EBADFD;
- } catch(ArrayIndexOutOfBoundsException e) {
- return -EBADFD;
- }
- try {
- return fd.seek(offset,whence);
- } catch(IOException e) {
- System.err.println(e);
- return -EPIPE;
- }
- }
-
- // This will only be called by raise() to invoke the default handler
- // We don't have to worry about actually delivering the signal
- private int kill(int pid, int signal) {
- if(pid != PID) return -ESRCH;
- if(signal < 0 || signal >= 32) return -EINVAL;
- switch(signal) {
- case 0: return 0;
- case 17: // SIGSTOP
- case 18: // SIGTSTP
- case 21: // SIGTTIN
- case 22: // SIGTTOU
- state = PAUSED;
- break;
- case 19: // SIGCONT
- case 20: // SIGCHLD
- case 23: // SIGIO
- case 28: // SIGWINCH
- break;
- default: {
- String msg = "Terminating on signal: " + signal + "\n";
- exitStatus = 1;
- state = DONE;
- if(fds[2]==null) {
- System.out.print(msg);
- } else {
- byte[] b = msg.getBytes();
- try {
- fds[2].write(b,0,b.length);
- } catch(IOException e) { }
- }
- }
- }
- return 0;
- }
-
- private int getpid() { return PID; }
-
- protected int syscall(int syscall, int a, int b, int c, int d) {
- switch(syscall) {
- case SYS_null: return 0;
- case SYS_exit: exitStatus = a; state = DONE; return 0;
- case SYS_pause: state = PAUSED; return 0;
- case SYS_write: return write(a,b,c);
- case SYS_fstat: return fstat(a,b);
- case SYS_sbrk: return sbrk(a);
- case SYS_open: return open(a,b,c);
- case SYS_close: return close(a);
- case SYS_read: return read(a,b,c);
- case SYS_seek: return seek(a,b,c);
- case SYS_kill: return kill(a,b);
- case SYS_getpid: return getpid();
- default:
- System.err.println("Attempted to use unknown syscall: " + syscall);
- return -ENOSYS;
- }
- }
-
- // Helper function to read a cstring from main memory
- private String cstring(int addr) throws ReadFaultException {
- StringBuffer sb = new StringBuffer();
- for(;;) {
- int word = memRead(addr&~3);
- switch(addr&3) {
- case 0: if(((word>>>24)&0xff)==0) return sb.toString(); sb.append((char)((word>>>24)&0xff)); addr++;
- case 1: if(((word>>>16)&0xff)==0) return sb.toString(); sb.append((char)((word>>>16)&0xff)); addr++;
- case 2: if(((word>>> 8)&0xff)==0) return sb.toString(); sb.append((char)((word>>> 8)&0xff)); addr++;
- case 3: if(((word>>> 0)&0xff)==0) return sb.toString(); sb.append((char)((word>>> 0)&0xff)); addr++;
- }
- }
- }
-
- // Exceptions
- public static class ReadFaultException extends FaultException {
- public ReadFaultException(int addr) { super(addr); }
- }
- public static class WriteFaultException extends FaultException {
- public WriteFaultException(int addr) { super(addr); }
- }
- public static abstract class FaultException extends EmulationException {
- private int addr;
- public FaultException(int addr) { this.addr = addr; }
- public String getMessage() { return "fault at: " + toHex(addr); }
- }
- public static class EmulationException extends Exception {
- public EmulationException() { }
- public EmulationException(String s) { super(s); }
- }
-
- // FileInfo classes - used by stat(2)
- static class FileInfo {
- public static final int S_IFIFO = 0010000;
- public static final int S_FCHR = 0020000;
- public static final int S_IFDIR = 0040000;
- public static final int S_IFREG = 0100000;
-
- public int size() { return 0; }
- public int type() { return S_IFIFO; }
- public long modTime() { return 0; }
- }
-
- public static class FileFileInfo extends FileInfo {
- public File f;
- public FileFileInfo(File f) { this.f = f; }
- public int size() { return (int)f.length(); }
- public int type() { return f.isDirectory() ? S_IFDIR : S_IFREG; }
- public long modTime() { return f.lastModified(); }
- }
-
- // File descriptor classes
- public static abstract class FileDescriptor {
- public boolean readable() { return false; }
- public boolean writable() { return false; }
-
- private static final FileInfo nullFi = new FileInfo();
- private FileInfo fi;
- public FileInfo fileInfo() { return fi; }
-
- FileDescriptor() { this(null); }
- FileDescriptor(FileInfo fi) { this.fi = fi==null ? nullFi : fi; }
-
- public int read(byte[] a, int off, int length) throws IOException { throw new IOException("no definition"); }
- public int write(byte[] a, int off, int length) throws IOException { throw new IOException("no definition"); }
-
- public int seek(int n, int whence) throws IOException { return -ESPIPE; }
- public boolean isatty() { return false; }
-
- void close() { }
- }
-
- public static class RegularFileDescriptor extends FileDescriptor {
- private int mode;
- private RandomAccessFile raf;
- public boolean readable() { return mode != 1; }
- public boolean writable() { return mode != 0; }
-
- RegularFileDescriptor(File f,int m) throws IOException {
- super(new FileFileInfo(f));
- String mode = m == 0 ? "r" : "rw";
- this.mode = m;
- raf = new RandomAccessFile(f,mode);
- if(raf.length() >= Integer.MAX_VALUE) throw new IOException("File too large");
- }
-
- public int seek(int n, int whence) throws IOException {
- final int SEEK_SET = 0;
- final int SEEK_CUR = 1;
- final int SEEK_END = 2;
-
- switch(whence) {
- case SEEK_SET: break;
- case SEEK_CUR: n = (int)(raf.getFilePointer()+n); break;
- case SEEK_END: n = (int)(raf.length()+n); break;
- default: return -EINVAL;
- }
- raf.seek(n);
- return n;
- }
-
- public int write(byte[] a, int off, int length) throws IOException { raf.write(a,off,length); return length; }
- public int read(byte[] a, int off, int length) throws IOException { int n = raf.read(a,off,length); return n < 0 ? 0 : n; }
-
- void close() { try { raf.close(); } catch(Exception e) { } }
- }
-
- public class OutputStreamFD extends FileDescriptor {
- private OutputStream os;
- public boolean writable() { return true; }
- public OutputStreamFD(OutputStream os) { this.os = os; }
- public int write(byte[] a, int off, int length) throws IOException { os.write(a,off,length); return length; }
- }
-
- public class InputStreamFD extends FileDescriptor {
- private InputStream is;
- public boolean readable() { return true; }
- public InputStreamFD(InputStream is) { this.is = is; }
- public int read(byte[] a, int off, int length) throws IOException { int n = is.read(a,off,length); return n < 0 ? 0 : n; }
- }
-
- // Utility functions
- private byte[] byteBuf(int size) {
- if(_byteBuf==null) _byteBuf = new byte[size];
- else if(_byteBuf.length < size)
- _byteBuf = new byte[min(max(_byteBuf.length*2,size),MAX_CHUNK+8)];
- return _byteBuf;
- }
- protected final static String toHex(int n) { return "0x" + Long.toString(n & 0xffffffffL, 16); }
- protected final static int min(int a, int b) { return a < b ? a : b; }
- protected final static int max(int a, int b) { return a > b ? a : b; }
-}
-
-class ELF {
- private MyRandomAccessFile fd;
-
- public ELFHeader header;
- public PHeader[] pheaders;
- public SHeader[] sheaders;
-
- private boolean sectionReaderActive;
-
- public class ELFHeader {
- byte klass;
- byte data;
- byte osabi;
- byte abiversion;
-
- public static final short ET_EXEC = 2;
- public short type;
- public static final short EM_MIPS = 8;
- public short machine;
- public int version;
- public int entry;
- public int phoff;
- public int shoff;
- public int flags;
- public short ehsize;
- public short phentsize;
- public short phnum;
- public short shentsize;
- public short shnum;
- public short shstrndx;