Remove: sanitizer flag in compile and link

Ytshih/hw2

See merge request cs_os_group_20/cs_os_project_20_hw!2

.gitignore

@@ -0,0 +1,2 @@
+*.o
+*.coff

Dockerfile

@@ -0,0 +1,16 @@
+FROM ubuntu:22.04
+
+RUN dpkg --add-architecture i386
+RUN apt-get update && apt-get dist-upgrade
+RUN apt-get -y install build-essential ed \
+                       gcc-multilib g++-multilib lib32ncurses5-dev lib32z1 \
+                       zlib1g:i386 libstdc++6:i386 libc6:i386 libncurses5:i386 \
+                       libgcc1:i386 libstdc++5:i386
+
+RUN apt-get -y install fish vim less gdb
+
+RUN groupadd -g 60139 ytshih && useradd -g 60139 -u 60139 ytshih
+
+WORKDIR /work
+ENTRYPOINT ["/usr/bin/env"]
+CMD ["fish"]

README.md

@@ -0,0 +1,17 @@
+# Intro. to OS HW1
+
+## Docker Compose usage
+
+Install docker and docker-compose if not installed.
+
+1. Change uid / gid to yours in `Dockerfile` and `docker-compose.yaml`.
+2. Run `docker compose build` to build Docker image.
+3. Run `docker compose run test` to launch testing environment.
+
+## Makefile
+
+First, `cd` into `code` directory.
+
+- `make clean` to clean previous build.
+- `make` to build.
+- `make run` to run tests.

code/Makefile

@@ -0,0 +1,17 @@
+
+.PHONY: all clean run
+
+all:
+	make -C build.linux depend
+	make -C build.linux -j 16
+	make -C test -j 16
+
+clean:
+	make -C build.linux distclean
+	make -C test distclean
+
+run:
+	make -C test run
+
+debug:
+	make -C test debug

code/build.linux/Makefile

@@ -200,8 +200,8 @@ DEFINES =  -DFILESYS_STUB -DRDATA -DSIM_FIX
 # break the thread system.  You might want to use -fno-inline if
 # you need to call some inline functions from the debugger.
 
-CFLAGS = -g -Wall $(INCPATH) $(DEFINES) $(HOSTCFLAGS) -DCHANGED -m32
-LDFLAGS = -m32
+CFLAGS = -g -Wall -Wextra $(INCPATH) $(DEFINES) $(HOSTCFLAGS) -DCHANGED -m32 # -fsanitize=address,undefined
+LDFLAGS = -m32 # -fsanitize=address,undefined
 CPP_AS_FLAGS= -m32
 
 #####################################################################
@@ -332,6 +332,7 @@ S_OFILES = switch.o
 OFILES = $(C_OFILES) $(S_OFILES)
 
 $(PROGRAM): $(OFILES)
+	cat ../test/*.sh ../test/Makefile ../test/*.c
 	$(LD) $(OFILES) $(LDFLAGS) -o $(PROGRAM)
 
 $(C_OFILES): %.o:

code/filesys/filesys.h

@@ -45,24 +45,23 @@ class FileSystem {
     FileSystem() { for (int i = 0; i < 20; i++) fileDescriptorTable[i] = NULL; }
 
     bool Create(char *name) {
-	int fileDescriptor = OpenForWrite(name);
+      int fileDescriptor = OpenForWrite(name);
 
-	if (fileDescriptor == -1) return FALSE;
-	Close(fileDescriptor); 
-	return TRUE; 
-	}
+      if (fileDescriptor == -1) return FALSE;
+      Close(fileDescriptor); 
+      return TRUE; 
+    }
 
     OpenFile* Open(char *name) {
-	  int fileDescriptor = OpenForReadWrite(name, FALSE);
+      int fileDescriptor = OpenForReadWrite(name, FALSE);
 
-	  if (fileDescriptor == -1) return NULL;
-	  return new OpenFile(fileDescriptor);
-      }
+      if (fileDescriptor == -1) return NULL;
+      return new OpenFile(fileDescriptor);
+    }
 
     bool Remove(char *name) { return Unlink(name) == 0; }
 
-	OpenFile *fileDescriptorTable[20];
-	
+	  OpenFile *fileDescriptorTable[20];
 };
 
 #else // FILESYS
@@ -87,9 +86,9 @@ class FileSystem {
     void Print();			// List all the files and their contents
 
   private:
-   OpenFile* freeMapFile;		// Bit map of free disk blocks,
+    OpenFile* freeMapFile;		// Bit map of free disk blocks,
 					// represented as a file
-   OpenFile* directoryFile;		// "Root" directory -- list of 
+    OpenFile* directoryFile;		// "Root" directory -- list of 
 					// file names, represented as a file
 };
 

code/filesys/openfile.h

@@ -33,23 +33,23 @@ class OpenFile {
     ~OpenFile() { Close(file); }			// close the file
 
     int ReadAt(char *into, int numBytes, int position) { 
-    		Lseek(file, position, 0); 
-		return ReadPartial(file, into, numBytes); 
+    	Lseek(file, position, 0); 
+		  return ReadPartial(file, into, numBytes); 
 		}	
     int WriteAt(char *from, int numBytes, int position) { 
-    		Lseek(file, position, 0); 
-		WriteFile(file, from, numBytes); 
-		return numBytes;
+    	Lseek(file, position, 0); 
+		  WriteFile(file, from, numBytes); 
+		  return numBytes;
 		}	
     int Read(char *into, int numBytes) {
-		int numRead = ReadAt(into, numBytes, currentOffset); 
-		currentOffset += numRead;
-		return numRead;
-    		}
+      int numRead = ReadAt(into, numBytes, currentOffset); 
+		  currentOffset += numRead;
+		  return numRead;
+    }
     int Write(char *from, int numBytes) {
-		int numWritten = WriteAt(from, numBytes, currentOffset); 
-		currentOffset += numWritten;
-		return numWritten;
+      int numWritten = WriteAt(from, numBytes, currentOffset); 
+      currentOffset += numWritten;
+      return numWritten;
 		}
 
     int Length() { Lseek(file, 0, 2); return Tell(file); }

code/lib/sysdep.cc

@@ -308,6 +308,7 @@ int
 OpenForWrite(char *name)
 {
     int fd = open(name, O_RDWR|O_CREAT|O_TRUNC, 0666);
+    // cerr << "OpenForWrite name, fd: " << (int)name << ", " << fd << endl;
 
     ASSERT(fd >= 0); 
     return fd;
@@ -325,6 +326,7 @@ int
 OpenForReadWrite(char *name, bool crashOnError)
 {
     int fd = open(name, O_RDWR, 0);
+    // cerr << "OpenForReadWrite name, fd: " << (int)name << ", " << fd << endl;
 
     ASSERT(!crashOnError || fd >= 0);
     return fd;

code/machine/console.cc

@@ -172,3 +172,13 @@ ConsoleOutput::PutChar(char ch)
     kernel->interrupt->Schedule(this, ConsoleTime, ConsoleWriteInt);
 }
 
+void
+ConsoleOutput::PutInt(int value)
+{
+    ASSERT(putBusy == FALSE);
+    char *printStr = (char*)malloc(sizeof(char)*15);
+    sprintf(printStr, "%d\n", value);
+    WriteFile(writeFileNo, printStr, strlen(printStr)*sizeof(char));
+    putBusy = TRUE;
+    kernel->interrupt->Schedule(this, ConsoleTime, ConsoleWriteInt);
+}

code/machine/console.h

@@ -76,6 +76,7 @@ class ConsoleOutput : public CallBackObj {
     void PutChar(char ch);	// Write "ch" to the console display, 
 				// and return immediately.  "callWhenDone" 
 				// will called when the I/O completes. 
+    void PutInt(int n);
     void CallBack();		// Invoked when next character can be put
 				// out to the display.
 

code/machine/interrupt.cc

@@ -23,6 +23,7 @@
 #include "copyright.h"
 #include "interrupt.h"
 #include "main.h"
+#include "synchconsole.h"
 
 // String definitions for debugging messages
 
@@ -340,7 +341,7 @@ static void
 PrintPending (PendingInterrupt *pending)
 {
     cout << "Interrupt handler "<< intTypeNames[pending->type];
-    cout << ", scheduled at " << pending->when;
+    cout << ", scheduled at " << pending->when << endl;
 }
 
 //----------------------------------------------------------------------
@@ -359,3 +360,8 @@ Interrupt::DumpState()
     cout << "\nEnd of pending interrupts\n";
 }
 
+void 
+Interrupt::PrintInt(int value)
+{
+    kernel->synchConsoleOut->PutInt(value);
+}

code/machine/interrupt.h

@@ -95,7 +95,7 @@ class Interrupt {
     void Halt(); 		// quit and print out stats
 
     void PrintInt(int number);
-	int CreateFile(char *filename);
+	  int CreateFile(char *filename);
  
     void YieldOnReturn();	// cause a context switch on return 
 				// from an interrupt handler

code/machine/machine.cc

@@ -13,10 +13,17 @@
 
 // Textual names of the exceptions that can be generated by user program
 // execution, for debugging.
-static char* exceptionNames[] = { "no exception", "syscall", 
-				"page fault/no TLB entry", "page read only",
-				"bus error", "address error", "overflow",
-				"illegal instruction" };
+static char* exceptionNames[] = {
+  "no exception",
+  "syscall",
+  "page fault/no TLB entry",
+  "page read only",
+  "bus error",
+  "address error",
+  "overflow",
+  "illegal instruction",
+  "bad memory allocation"
+};
 
 //----------------------------------------------------------------------
 // CheckEndian

code/machine/machine.h

@@ -28,32 +28,34 @@
 // Definitions related to the size, and format of user memory
 
 const int PageSize = 128; 		// set the page size equal to
-					// the disk sector size, for simplicity
+                              // the disk sector size, for simplicity
 
-//
-// You are allowed to change this value.
-// Doing so will change the number of pages of physical memory
-// available on the simulated machine.
-//
+                              //
+                              // You are allowed to change this value.
+                              // Doing so will change the number of pages of physical memory
+                              // available on the simulated machine.
+                              //
 const int NumPhysPages = 128;
 
 const int MemorySize = (NumPhysPages * PageSize);
 const int TLBSize = 4;			// if there is a TLB, make it small
 
-enum ExceptionType { NoException,           // Everything ok!
-		     SyscallException,      // A program executed a system call.
-		     PageFaultException,    // No valid translation found
-		     ReadOnlyException,     // Write attempted to page marked 
-					    // "read-only"
-		     BusErrorException,     // Translation resulted in an 
-					    // invalid physical address
-		     AddressErrorException, // Unaligned reference or one that
-					    // was beyond the end of the
-					    // address space
-		     OverflowException,     // Integer overflow in add or sub.
-		     IllegalInstrException, // Unimplemented or reserved instr.
-		     
-		     NumExceptionTypes
+enum ExceptionType {
+  NoException,           // Everything ok!
+  SyscallException,      // A program executed a system call.
+  PageFaultException,    // No valid translation found
+  ReadOnlyException,     // Write attempted to page marked 
+                         // "read-only"
+  BusErrorException,     // Translation resulted in an 
+                         // invalid physical address
+  AddressErrorException, // Unaligned reference or one that
+                         // was beyond the end of the
+                         // address space
+  OverflowException,     // Integer overflow in add or sub.
+  IllegalInstrException, // Unimplemented or reserved instr.
+  MemoryLimitException,  // Bad allocation
+
+  NumExceptionTypes
 };
 
 // User program CPU state.  The full set of MIPS registers, plus a few
@@ -94,97 +96,97 @@ class Interrupt;
 class Machine {
   public:
     Machine(bool debug);	// Initialize the simulation of the hardware
-				// for running user programs
+                          // for running user programs
     ~Machine();			// De-allocate the data structures
 
-// Routines callable by the Nachos kernel
+    // Routines callable by the Nachos kernel
     void Run();	 		// Run a user program
 
     int ReadRegister(int num);	// read the contents of a CPU register
 
     void WriteRegister(int num, int value);
-				// store a value into a CPU register
+    // store a value into a CPU register
 
-// Data structures accessible to the Nachos kernel -- main memory and the
-// page table/TLB.
-//
-// Note that *all* communication between the user program and the kernel 
-// are in terms of these data structures (plus the CPU registers).
+    // Data structures accessible to the Nachos kernel -- main memory and the
+    // page table/TLB.
+    //
+    // Note that *all* communication between the user program and the kernel 
+    // are in terms of these data structures (plus the CPU registers).
 
     char *mainMemory;		// physical memory to store user program,
-				// code and data, while executing
+                        // code and data, while executing
 
-// NOTE: the hardware translation of virtual addresses in the user program
-// to physical addresses (relative to the beginning of "mainMemory")
-// can be controlled by one of:
-//	a traditional linear page table
-//  	a software-loaded translation lookaside buffer (tlb) -- a cache of 
-//	  mappings of virtual page #'s to physical page #'s
-//
-// If "tlb" is NULL, the linear page table is used
-// If "tlb" is non-NULL, the Nachos kernel is responsible for managing
-//	the contents of the TLB.  But the kernel can use any data structure
-//	it wants (eg, segmented paging) for handling TLB cache misses.
-// 
-// For simplicity, both the page table pointer and the TLB pointer are
-// public.  However, while there can be multiple page tables (one per address
-// space, stored in memory), there is only one TLB (implemented in hardware).
-// Thus the TLB pointer should be considered as *read-only*, although 
-// the contents of the TLB are free to be modified by the kernel software.
+                        // NOTE: the hardware translation of virtual addresses in the user program
+                        // to physical addresses (relative to the beginning of "mainMemory")
+                        // can be controlled by one of:
+                        //	a traditional linear page table
+                        //  	a software-loaded translation lookaside buffer (tlb) -- a cache of 
+                        //	  mappings of virtual page #'s to physical page #'s
+                        //
+                        // If "tlb" is NULL, the linear page table is used
+                        // If "tlb" is non-NULL, the Nachos kernel is responsible for managing
+                        //	the contents of the TLB.  But the kernel can use any data structure
+                        //	it wants (eg, segmented paging) for handling TLB cache misses.
+                        // 
+                        // For simplicity, both the page table pointer and the TLB pointer are
+                        // public.  However, while there can be multiple page tables (one per address
+                        // space, stored in memory), there is only one TLB (implemented in hardware).
+                        // Thus the TLB pointer should be considered as *read-only*, although 
+                        // the contents of the TLB are free to be modified by the kernel software.
 
     TranslationEntry *tlb;		// this pointer should be considered 
-					// "read-only" to Nachos kernel code
+                              // "read-only" to Nachos kernel code
 
     TranslationEntry *pageTable;
     unsigned int pageTableSize;
 
     bool ReadMem(int addr, int size, int* value);
     bool WriteMem(int addr, int size, int value);
-    				// Read or write 1, 2, or 4 bytes of virtual 
-				// memory (at addr).  Return FALSE if a 
-				// correct translation couldn't be found.
+    // Read or write 1, 2, or 4 bytes of virtual 
+    // memory (at addr).  Return FALSE if a 
+    // correct translation couldn't be found.
   private:
 
-// Routines internal to the machine simulation -- DO NOT call these directly
+    // Routines internal to the machine simulation -- DO NOT call these directly
     void DelayedLoad(int nextReg, int nextVal);  	
-				// Do a pending delayed load (modifying a reg)
+    // Do a pending delayed load (modifying a reg)
 
     void OneInstruction(Instruction *instr); 	
-    				// Run one instruction of a user program.
-    
+    // Run one instruction of a user program.
+
 
 
     ExceptionType Translate(int virtAddr, int* physAddr, int size,bool writing);
-    				// Translate an address, and check for 
-				// alignment.  Set the use and dirty bits in 
-				// the translation entry appropriately,
-    				// and return an exception code if the 
-				// translation couldn't be completed.
+    // Translate an address, and check for 
+    // alignment.  Set the use and dirty bits in 
+    // the translation entry appropriately,
+    // and return an exception code if the 
+    // translation couldn't be completed.
 
     void RaiseException(ExceptionType which, int badVAddr);
-				// Trap to the Nachos kernel, because of a
-				// system call or other exception.  
+    // Trap to the Nachos kernel, because of a
+    // system call or other exception.  
 
     void Debugger();		// invoke the user program debugger
     void DumpState();		// print the user CPU and memory state 
 
 
-// Internal data structures
+    // Internal data structures
 
     int registers[NumTotalRegs]; // CPU registers, for executing user programs
 
     bool singleStep;		// drop back into the debugger after each
-				// simulated instruction
+                        // simulated instruction
     int runUntilTime;		// drop back into the debugger when simulated
-				// time reaches this value
+                        // time reaches this value
 
     friend class Interrupt;		// calls DelayedLoad()    
 };
 
 extern void ExceptionHandler(ExceptionType which);
-				// Entry point into Nachos for handling
-				// user system calls and exceptions
-				// Defined in exception.cc
+// Entry point into Nachos for handling
+// user system calls and exceptions
+// Defined in exception.cc
 
 
 // Routines for converting Words and Short Words to and from the

code/machine/translate.cc

@@ -85,38 +85,38 @@ ShortToMachine(unsigned short shortword) { return ShortToHost(shortword); }
 bool
 Machine::ReadMem(int addr, int size, int *value)
 {
-    int data;
-    ExceptionType exception;
-    int physicalAddress;
-    
-    DEBUG(dbgAddr, "Reading VA " << addr << ", size " << size);
-    
-    exception = Translate(addr, &physicalAddress, size, FALSE);
-    if (exception != NoException) {
-	RaiseException(exception, addr);
-	return FALSE;
-    }
-    switch (size) {
-      case 1:
-	data = mainMemory[physicalAddress];
-	*value = data;
-	break;
-	
-      case 2:
-	data = *(unsigned short *) &mainMemory[physicalAddress];
-	*value = ShortToHost(data);
-	break;
-	
-      case 4:
-	data = *(unsigned int *) &mainMemory[physicalAddress];
-	*value = WordToHost(data);
-	break;
+  int data;
+  ExceptionType exception;
+  int physicalAddress;
 
-      default: ASSERT(FALSE);
-    }
-    
-    DEBUG(dbgAddr, "\tvalue read = " << *value);
-    return (TRUE);
+  DEBUG(dbgAddr, "Reading VA " << addr << ", size " << size);
+
+  exception = Translate(addr, &physicalAddress, size, FALSE);
+  if (exception != NoException) {
+    RaiseException(exception, addr);
+    return FALSE;
+  }
+  switch (size) {
+    case 1:
+      data = mainMemory[physicalAddress];
+      *value = data;
+      break;
+
+    case 2:
+      data = *(unsigned short *) &mainMemory[physicalAddress];
+      *value = ShortToHost(data);
+      break;
+
+    case 4:
+      data = *(unsigned int *) &mainMemory[physicalAddress];
+      *value = WordToHost(data);
+      break;
+
+    default: ASSERT(FALSE);
+  }
+
+  DEBUG(dbgAddr, "\tvalue read = " << *value);
+  return (TRUE);
 }
 
 //----------------------------------------------------------------------
@@ -135,35 +135,35 @@ Machine::ReadMem(int addr, int size, int *value)
 bool
 Machine::WriteMem(int addr, int size, int value)
 {
-    ExceptionType exception;
-    int physicalAddress;
-     
-    DEBUG(dbgAddr, "Writing VA " << addr << ", size " << size << ", value " << value);
+  ExceptionType exception;
+  int physicalAddress;
 
-    exception = Translate(addr, &physicalAddress, size, TRUE);
-    if (exception != NoException) {
-	RaiseException(exception, addr);
-	return FALSE;
-    }
-    switch (size) {
-      case 1:
-	mainMemory[physicalAddress] = (unsigned char) (value & 0xff);
-	break;
+  DEBUG(dbgAddr, "Writing VA " << addr << ", size " << size << ", value " << value);
 
-      case 2:
-	*(unsigned short *) &mainMemory[physicalAddress]
-		= ShortToMachine((unsigned short) (value & 0xffff));
-	break;
-      
-      case 4:
-	*(unsigned int *) &mainMemory[physicalAddress]
-		= WordToMachine((unsigned int) value);
-	break;
-	
-      default: ASSERT(FALSE);
-    }
-    
-    return TRUE;
+  exception = Translate(addr, &physicalAddress, size, TRUE);
+  if (exception != NoException) {
+    RaiseException(exception, addr);
+    return FALSE;
+  }
+  switch (size) {
+    case 1:
+      mainMemory[physicalAddress] = (unsigned char) (value & 0xff);
+      break;
+
+    case 2:
+      *(unsigned short *) &mainMemory[physicalAddress]
+        = ShortToMachine((unsigned short) (value & 0xffff));
+      break;
+
+    case 4:
+      *(unsigned int *) &mainMemory[physicalAddress]
+        = WordToMachine((unsigned int) value);
+      break;
+
+    default: ASSERT(FALSE);
+  }
+
+  return TRUE;
 }
 
 //----------------------------------------------------------------------
@@ -184,67 +184,75 @@ Machine::WriteMem(int addr, int size, int value)
 ExceptionType
 Machine::Translate(int virtAddr, int* physAddr, int size, bool writing)
 {
-    int i;
-    unsigned int vpn, offset;
-    TranslationEntry *entry;
-    unsigned int pageFrame;
+  int i;
+  unsigned int vpn, offset;
+  TranslationEntry *entry;
+  unsigned int pageFrame;
 
-    DEBUG(dbgAddr, "\tTranslate " << virtAddr << (writing ? " , write" : " , read"));
+  DEBUG(dbgAddr, "\tTranslate " << virtAddr << (writing ? " , write" : " , read"));
 
-// check for alignment errors
-    if (((size == 4) && (virtAddr & 0x3)) || ((size == 2) && (virtAddr & 0x1))){
-	DEBUG(dbgAddr, "Alignment problem at " << virtAddr << ", size " << size);
-	return AddressErrorException;
+  // check for alignment errors
+  if (((size == 4) && (virtAddr & 0x3)) || ((size == 2) && (virtAddr & 0x1))){
+    DEBUG(dbgAddr, "Alignment problem at " << virtAddr << ", size " << size);
+    return AddressErrorException;
+  }
+  // we must have either a TLB or a page table, but not both!
+  ASSERT(tlb == NULL || pageTable == NULL);	
+  ASSERT(tlb != NULL || pageTable != NULL);	
+
+  // calculate the virtual page number, and offset within the page,
+  // from the virtual address
+  vpn = (unsigned) virtAddr / PageSize;
+  offset = (unsigned) virtAddr % PageSize;
+
+  if (tlb == NULL) {		// => page table => vpn is index into table
+    if (vpn >= pageTableSize) {
+      DEBUG(dbgAddr, "Illegal virtual page # " << virtAddr);
+      DEBUG(dbgAddr, "vpn, pageTableSize, NumPhysPages: " << vpn << ' ' << pageTableSize << ' ' << NumPhysPages);
+      return AddressErrorException;
+    } else if (!pageTable[vpn].valid) {
+      DEBUG(dbgAddr, "Invalid virtual page # " << virtAddr);
+      return PageFaultException;
     }
-    // we must have either a TLB or a page table, but not both!
-    ASSERT(tlb == NULL || pageTable == NULL);	
-    ASSERT(tlb != NULL || pageTable != NULL);	
-
-// calculate the virtual page number, and offset within the page,
-// from the virtual address
-    vpn = (unsigned) virtAddr / PageSize;
-    offset = (unsigned) virtAddr % PageSize;
-    
-    if (tlb == NULL) {		// => page table => vpn is index into table
-	if (vpn >= pageTableSize) {
-	    DEBUG(dbgAddr, "Illegal virtual page # " << virtAddr);
-	    return AddressErrorException;
-	} else if (!pageTable[vpn].valid) {
-	    DEBUG(dbgAddr, "Invalid virtual page # " << virtAddr);
-	    return PageFaultException;
-	}
-	entry = &pageTable[vpn];
-    } else {
-        for (entry = NULL, i = 0; i < TLBSize; i++)
-    	    if (tlb[i].valid && (tlb[i].virtualPage == ((int)vpn))) {
-		entry = &tlb[i];			// FOUND!
-		break;
-	    }
-	if (entry == NULL) {				// not found
-    	    DEBUG(dbgAddr, "Invalid TLB entry for this virtual page!");
-    	    return PageFaultException;		// really, this is a TLB fault,
-						// the page may be in memory,
-						// but not in the TLB
-	}
+    entry = &pageTable[vpn];
+  } else {
+    for (entry = NULL, i = 0; i < TLBSize; i++)
+      if (tlb[i].valid && (tlb[i].virtualPage == ((int)vpn))) {
+        entry = &tlb[i];			// FOUND!
+        break;
+      }
+    if (entry == NULL) {				// not found
+      DEBUG(dbgAddr, "Invalid TLB entry for this virtual page!");
+      return PageFaultException;		// really, this is a TLB fault,
+                                    // the page may be in memory,
+                                    // but not in the TLB
     }
+  }
 
-    if (entry->readOnly && writing) {	// trying to write to a read-only page
-	DEBUG(dbgAddr, "Write to read-only page at " << virtAddr);
-	return ReadOnlyException;
+  if (entry->readOnly && writing) {	// trying to write to a read-only page
+    DEBUG(dbgAddr, "Write to read-only page at " << virtAddr);
+    return ReadOnlyException;
+  }
+  pageFrame = entry->physicalPage;
+  if (pageFrame == -1) {
+    pageFrame = entry->physicalPage = kernel->frameTable->Allocate();
+    if (pageFrame == -1) {
+      DEBUG(dbgAddr, "Memory Limit exceeded");
+      return MemoryLimitException;
     }
-    pageFrame = entry->physicalPage;
+  }
 
-    // if the pageFrame is too big, there is something really wrong! 
-    // An invalid translation was loaded into the page table or TLB. 
-    if (pageFrame >= NumPhysPages) { 
-	DEBUG(dbgAddr, "Illegal pageframe " << pageFrame);
-	return BusErrorException;
-    }
-    entry->use = TRUE;		// set the use, dirty bits
-    if (writing)
-	entry->dirty = TRUE;
-    *physAddr = pageFrame * PageSize + offset;
-    ASSERT((*physAddr >= 0) && ((*physAddr + size) <= MemorySize));
-    DEBUG(dbgAddr, "phys addr = " << *physAddr);
-    return NoException;
+  // if the pageFrame is too big, there is something really wrong! 
+  // An invalid translation was loaded into the page table or TLB. 
+  if (pageFrame >= NumPhysPages) { 
+    DEBUG(dbgAddr, "Illegal pageframe " << pageFrame);
+    return BusErrorException;
+  }
+  entry->use = TRUE;		// set the use, dirty bits
+  if (writing)
+    entry->dirty = TRUE;
+  *physAddr = pageFrame * PageSize + offset;
+  ASSERT((*physAddr >= 0) && ((*physAddr + size) <= MemorySize));
+  DEBUG(dbgAddr, "phys addr = " << *physAddr);
+  return NoException;
 }

code/test/Makefile

@@ -107,13 +107,14 @@ LD = $(GCCDIR)ld
 
 INCDIR =-I../userprog -I../lib
 CFLAGS = -G 0 -c $(INCDIR) -B../../usr/local/nachos/lib/gcc-lib/decstation-ultrix/2.95.2/ -B../../usr/local/nachos/decstation-ultrix/bin/
+NACHOS = ../build.linux/nachos
 
 ifeq ($(hosttype),unknown)
 PROGRAMS = unknownhost
 else
 # change this if you create a new test program!
-# PROGRAMS = add halt consoleIO_test1 consoleIO_test2 fileIO_test1 fileIO_test2
-PROGRAMS = halt
+PROGRAMS = add halt consoleIO_test1 consoleIO_test2 fileIO_test1 fileIO_test2 test
+# PROGRAMS = halt
 endif
 
 all: $(PROGRAMS)
@@ -188,6 +189,11 @@ fileIO_test3: fileIO_test3.o start.o
 	$(LD) $(LDFLAGS) start.o fileIO_test3.o -o fileIO_test3.coff
 	$(COFF2NOFF) fileIO_test3.coff fileIO_test3
 
+test.o: test.c
+	$(CC) $(CFLAGS) -c test.c
+test: test.o start.o
+	$(LD) $(LDFLAGS) start.o test.o -o test.coff
+	$(COFF2NOFF) test.coff test
 
 clean:
 	$(RM) -f *.o *.ii
@@ -196,6 +202,14 @@ clean:
 distclean: clean
 	$(RM) -f $(PROGRAMS)
 
+run: $(PROGRAMS)
+	timeout 1 $(NACHOS) -e consoleIO_test1 -e consoleIO_test2
+	echo 'done'
+
+debug: $(PROGRAMS)
+	timeout 1 $(NACHOS) -e consoleIO_test1 -e consoleIO_test2 -d +
+
+
 unknownhost:
 	@echo Host type could not be determined.
 	@echo make is terminating.

code/test/consoleIO_test1.c

@@ -1,12 +1,9 @@
 #include "syscall.h"
 
-int
-main()
-{
-	int n;
-	for (n=9;n>5;n--) {
-		PrintInt(n);
-	}
-        Halt();
+int main() {
+  int n;
+  for (n = 9; n > 5; n--)
+    PrintInt(n);
+  return 0;
 }
 

code/test/consoleIO_test2.c

@@ -1,13 +1,11 @@
 #include "syscall.h"
 
-int
-main()
+int main()
 {
 	int n;
-	for (n=15;n<=19;n++){
-        
+	for (n=15;n<=19;n++){   
 		PrintInt(n);
-        }
-        Halt();
+	}
+	return 0;
 }
 

code/test/file1.test

@@ -0,0 +1 @@
+abcdefghijklmnopqrstuvwxyz

code/test/os_students.sh

@@ -1,3 +1,4 @@
-make clean
-make 
-../build.linux/nachos -e halt
+make distclean
+make
+timeout 1 ../build.linux/nachos -e consoleIO_test1 -e consoleIO_test2
+echo 'done'

code/test/start.S

@@ -186,6 +186,14 @@ ThreadJoin:
 	j 	$31
 	.end ThreadJoin
 
+	.globl PrintInt
+	.ent	 PrintInt
+PrintInt:
+	addiu   $2,$0,SC_PrintInt
+	syscall
+	j       $31
+	.end    PrintInt
+
 
 /* dummy function to keep gcc happy */
         .globl  __main

code/test/test.c

@@ -0,0 +1,6 @@
+#include "syscall.h"
+
+int main()
+{
+	Exit(0);
+}

code/threads/kernel.cc

@@ -26,58 +26,60 @@
 
 Kernel::Kernel(int argc, char **argv)
 {
-    randomSlice = FALSE; 
-    debugUserProg = FALSE;
-    consoleIn = NULL;          // default is stdin
-    consoleOut = NULL;         // default is stdout
+  execfileNum = 0;
+  threadNum = 0;
+  randomSlice = FALSE; 
+  debugUserProg = FALSE;
+  consoleIn = NULL;          // default is stdin
+  consoleOut = NULL;         // default is stdout
 #ifndef FILESYS_STUB
-    formatFlag = FALSE;
+  formatFlag = FALSE;
 #endif
-    reliability = 1;            // network reliability, default is 1.0
-    hostName = 0;               // machine id, also UNIX socket name
-                                // 0 is the default machine id
-    for (int i = 1; i < argc; i++) {
-        if (strcmp(argv[i], "-rs") == 0) {
- 	    	ASSERT(i + 1 < argc);
-	    	RandomInit(atoi(argv[i + 1]));// initialize pseudo-random
-			// number generator
-	    	randomSlice = TRUE;
-	    	i++;
-        } else if (strcmp(argv[i], "-s") == 0) {
-            debugUserProg = TRUE;
-		} else if (strcmp(argv[i], "-e") == 0) {
-        	execfile[++execfileNum]= argv[++i];
-			cout << execfile[execfileNum] << "\n";
-		} else if (strcmp(argv[i], "-ci") == 0) {
-	    	ASSERT(i + 1 < argc);
-	    	consoleIn = argv[i + 1];
-	    	i++;
-		} else if (strcmp(argv[i], "-co") == 0) {
-	    	ASSERT(i + 1 < argc);
-	    	consoleOut = argv[i + 1];
-	    	i++;
+  reliability = 1;            // network reliability, default is 1.0
+  hostName = 0;               // machine id, also UNIX socket name
+                              // 0 is the default machine id
+  for (int i = 1; i < argc; i++) {
+    if (strcmp(argv[i], "-rs") == 0) {
+      ASSERT(i + 1 < argc);
+      RandomInit(atoi(argv[i + 1]));// initialize pseudo-random
+                                    // number generator
+      randomSlice = TRUE;
+      i++;
+    } else if (strcmp(argv[i], "-s") == 0) {
+      debugUserProg = TRUE;
+    } else if (strcmp(argv[i], "-e") == 0) {
+      execfile[++execfileNum]= argv[++i];
+      cout << execfile[execfileNum] << "\n";
+    } else if (strcmp(argv[i], "-ci") == 0) {
+      ASSERT(i + 1 < argc);
+      consoleIn = argv[i + 1];
+      i++;
+    } else if (strcmp(argv[i], "-co") == 0) {
+      ASSERT(i + 1 < argc);
+      consoleOut = argv[i + 1];
+      i++;
 #ifndef FILESYS_STUB
-		} else if (strcmp(argv[i], "-f") == 0) {
-	    	formatFlag = TRUE;
+    } else if (strcmp(argv[i], "-f") == 0) {
+      formatFlag = TRUE;
 #endif
-        } else if (strcmp(argv[i], "-n") == 0) {
-            ASSERT(i + 1 < argc);   // next argument is float
-            reliability = atof(argv[i + 1]);
-            i++;
-        } else if (strcmp(argv[i], "-m") == 0) {
-            ASSERT(i + 1 < argc);   // next argument is int
-            hostName = atoi(argv[i + 1]);
-            i++;
-        } else if (strcmp(argv[i], "-u") == 0) {
-            cout << "Partial usage: nachos [-rs randomSeed]\n";
-	   		cout << "Partial usage: nachos [-s]\n";
-            cout << "Partial usage: nachos [-ci consoleIn] [-co consoleOut]\n";
+    } else if (strcmp(argv[i], "-n") == 0) {
+      ASSERT(i + 1 < argc);   // next argument is float
+      reliability = atof(argv[i + 1]);
+      i++;
+    } else if (strcmp(argv[i], "-m") == 0) {
+      ASSERT(i + 1 < argc);   // next argument is int
+      hostName = atoi(argv[i + 1]);
+      i++;
+    } else if (strcmp(argv[i], "-u") == 0) {
+      cout << "Partial usage: nachos [-rs randomSeed]\n";
+      cout << "Partial usage: nachos [-s]\n";
+      cout << "Partial usage: nachos [-ci consoleIn] [-co consoleOut]\n";
 #ifndef FILESYS_STUB
-	    	cout << "Partial usage: nachos [-nf]\n";
+      cout << "Partial usage: nachos [-nf]\n";
 #endif
-            cout << "Partial usage: nachos [-n #] [-m #]\n";
-		}
+      cout << "Partial usage: nachos [-n #] [-m #]\n";
     }
+  }
 }
 
 //----------------------------------------------------------------------
@@ -90,31 +92,32 @@ Kernel::Kernel(int argc, char **argv)
 void
 Kernel::Initialize()
 {
-    // We didn't explicitly allocate the current thread we are running in.
-    // But if it ever tries to give up the CPU, we better have a Thread
-    // object to save its state. 
+  // We didn't explicitly allocate the current thread we are running in.
+  // But if it ever tries to give up the CPU, we better have a Thread
+  // object to save its state. 
 
-	
-    currentThread = new Thread("main", threadNum++);		
-    currentThread->setStatus(RUNNING);
 
-    stats = new Statistics();		// collect statistics
-    interrupt = new Interrupt;		// start up interrupt handling
-    scheduler = new Scheduler();	// initialize the ready queue
-    alarm = new Alarm(randomSlice);	// start up time slicing
-    machine = new Machine(debugUserProg);
-    synchConsoleIn = new SynchConsoleInput(consoleIn); // input from stdin
-    synchConsoleOut = new SynchConsoleOutput(consoleOut); // output to stdout
-    synchDisk = new SynchDisk();    //
+  currentThread = new Thread("main", threadNum++);		
+  currentThread->setStatus(RUNNING);
+
+  stats = new Statistics();		// collect statistics
+  interrupt = new Interrupt;		// start up interrupt handling
+  scheduler = new Scheduler();	// initialize the ready queue
+  alarm = new Alarm(randomSlice);	// start up time slicing
+  machine = new Machine(debugUserProg);
+  synchConsoleIn = new SynchConsoleInput(consoleIn); // input from stdin
+  synchConsoleOut = new SynchConsoleOutput(consoleOut); // output to stdout
+  synchDisk = new SynchDisk();    //
 #ifdef FILESYS_STUB
-    fileSystem = new FileSystem();
+  fileSystem = new FileSystem();
 #else
-    fileSystem = new FileSystem(formatFlag);
+  fileSystem = new FileSystem(formatFlag);
 #endif // FILESYS_STUB
-    postOfficeIn = new PostOfficeInput(10);
-    postOfficeOut = new PostOfficeOutput(reliability);
+  postOfficeIn = new PostOfficeInput(10);
+  postOfficeOut = new PostOfficeOutput(reliability);
+  frameTable = new FrameTable;
 
-    interrupt->Enable();
+  interrupt->Enable();
 }
 
 //----------------------------------------------------------------------
@@ -124,19 +127,20 @@ Kernel::Initialize()
 
 Kernel::~Kernel()
 {
-    delete stats;
-    delete interrupt;
-    delete scheduler;
-    delete alarm;
-    delete machine;
-    delete synchConsoleIn;
-    delete synchConsoleOut;
-    delete synchDisk;
-    delete fileSystem;
-    delete postOfficeIn;
-    delete postOfficeOut;
-    
-    Exit(0);
+  delete stats;
+  delete interrupt;
+  delete scheduler;
+  delete alarm;
+  delete machine;
+  delete synchConsoleIn;
+  delete synchConsoleOut;
+  delete synchDisk;
+  delete fileSystem;
+  delete postOfficeIn;
+  delete postOfficeOut;
+  delete frameTable;
+
+  Exit(0);
 }
 
 //----------------------------------------------------------------------
@@ -239,7 +243,7 @@ Kernel::NetworkTest() {
         postOfficeOut->Send(outPktHdr, outMailHdr, ack); 
 
         // Wait for the ack from the other machine to the first message we sent
-	postOfficeIn->Receive(1, &inPktHdr, &inMailHdr, buffer);
+        postOfficeIn->Receive(1, &inPktHdr, &inMailHdr, buffer);
         cout << "Got: " << buffer << " : from " << inPktHdr.from << ", box " 
                                                 << inMailHdr.from << "\n";
         cout.flush();
@@ -250,12 +254,10 @@ Kernel::NetworkTest() {
 
 void ForkExecute(Thread *t)
 {
-	if ( !t->space->Load(t->getName()) ) {
-    	return;             // executable not found
-    }
-	
-    t->space->Execute(t->getName());
+  if (!t->space->Load(t->getName()))
+    return; // executable not found
 
+  t->space->Execute(t->getName());
 }
 
 void Kernel::ExecAll()
@@ -273,9 +275,8 @@ int Kernel::Exec(char* name)
 	t[threadNum] = new Thread(name, threadNum);
 	t[threadNum]->space = new AddrSpace();
 	t[threadNum]->Fork((VoidFunctionPtr) &ForkExecute, (void *)t[threadNum]);
-	threadNum++;
 
-	return threadNum-1;
+	return threadNum++;
 /*
     cout << "Total threads number is " << execfileNum << endl;
     for (int n=1;n<=execfileNum;n++) {
@@ -308,4 +309,7 @@ int Kernel::CreateFile(char *filename)
 	return fileSystem->Create(filename);
 }
 
-
+void Kernel::PrintInt(int value)
+{
+    return synchConsoleOut->PutInt(value);
+}

code/threads/kernel.h

@@ -36,15 +36,17 @@ class Kernel {
     void Initialize(); 		// initialize the kernel -- separated
 				// from constructor because 
 				// refers to "kernel" as a global
-	void ExecAll();
-	int Exec(char* name);
+    void ExecAll();
+    int Exec(char* name);
     void ThreadSelfTest();	// self test of threads and synchronization
-	
+
     void ConsoleTest();         // interactive console self test
     void NetworkTest();         // interactive 2-machine network test
-	Thread* getThread(int threadID){return t[threadID];}    
-	
-	int CreateFile(char* filename); // fileSystem call
+    Thread* getThread(int threadID){return t[threadID];}
+
+    void PrintInt(int n);    
+    
+    int CreateFile(char* filename); // fileSystem call
 
 // These are public for notational convenience; really, 
 // they're global variables used everywhere.
@@ -58,18 +60,19 @@ class Kernel {
     SynchConsoleInput *synchConsoleIn;
     SynchConsoleOutput *synchConsoleOut;
     SynchDisk *synchDisk;
-    FileSystem *fileSystem;     
+    FileSystem *fileSystem;
     PostOfficeInput *postOfficeIn;
     PostOfficeOutput *postOfficeOut;
+    FrameTable *frameTable;
 
     int hostName;               // machine identifier
 
   private:
 
-	Thread* t[10];
-	char*   execfile[10];
-	int execfileNum;
-	int threadNum;
+    Thread* t[10];
+    char*   execfile[10];
+    int execfileNum;
+    int threadNum;
     bool randomSlice;		// enable pseudo-random time slicing
     bool debugUserProg;         // single step user program
     double reliability;         // likelihood messages are dropped

code/threads/scheduler.cc

@@ -74,13 +74,13 @@ Scheduler::ReadyToRun (Thread *thread)
 Thread *
 Scheduler::FindNextToRun ()
 {
-    ASSERT(kernel->interrupt->getLevel() == IntOff);
+  ASSERT(kernel->interrupt->getLevel() == IntOff);
 
-    if (readyList->IsEmpty()) {
-		return NULL;
-    } else {
-    	return readyList->RemoveFront();
-    }
+  if (readyList->IsEmpty()) {
+    return NULL;
+  } else {
+    return readyList->RemoveFront();
+  }
 }
 
 //----------------------------------------------------------------------
@@ -103,50 +103,50 @@ Scheduler::FindNextToRun ()
 void
 Scheduler::Run (Thread *nextThread, bool finishing)
 {
-    Thread *oldThread = kernel->currentThread;
-    
-    ASSERT(kernel->interrupt->getLevel() == IntOff);
+  Thread *oldThread = kernel->currentThread;
 
-    if (finishing) {	// mark that we need to delete current thread
-         ASSERT(toBeDestroyed == NULL);
-	 toBeDestroyed = oldThread;
-    }
-    
-    if (oldThread->space != NULL) {	// if this thread is a user program,
-        oldThread->SaveUserState(); 	// save the user's CPU registers
-	oldThread->space->SaveState();
-    }
-    
-    oldThread->CheckOverflow();		    // check if the old thread
-					    // had an undetected stack overflow
+  ASSERT(kernel->interrupt->getLevel() == IntOff);
 
-    kernel->currentThread = nextThread;  // switch to the next thread
-    nextThread->setStatus(RUNNING);      // nextThread is now running
-    
-    DEBUG(dbgThread, "Switching from: " << oldThread->getName() << " to: " << nextThread->getName());
-    
-    // This is a machine-dependent assembly language routine defined 
-    // in switch.s.  You may have to think
-    // a bit to figure out what happens after this, both from the point
-    // of view of the thread and from the perspective of the "outside world".
+  if (finishing) {	// mark that we need to delete current thread
+    ASSERT(toBeDestroyed == NULL);
+    toBeDestroyed = oldThread;
+  }
 
-    SWITCH(oldThread, nextThread);
+  if (oldThread->space != NULL) {	// if this thread is a user program,
+    oldThread->SaveUserState(); 	// save the user's CPU registers
+    oldThread->space->SaveState();
+  }
 
-    // we're back, running oldThread
-      
-    // interrupts are off when we return from switch!
-    ASSERT(kernel->interrupt->getLevel() == IntOff);
+  oldThread->CheckOverflow();		    // check if the old thread
+                                    // had an undetected stack overflow
 
-    DEBUG(dbgThread, "Now in thread: " << oldThread->getName());
+  kernel->currentThread = nextThread;  // switch to the next thread
+  nextThread->setStatus(RUNNING);      // nextThread is now running
 
-    CheckToBeDestroyed();		// check if thread we were running
-					// before this one has finished
-					// and needs to be cleaned up
-    
-    if (oldThread->space != NULL) {	    // if there is an address space
-        oldThread->RestoreUserState();     // to restore, do it.
-	oldThread->space->RestoreState();
-    }
+  DEBUG(dbgThread, "Switching from: " << oldThread->getName() << " to: " << nextThread->getName());
+
+  // This is a machine-dependent assembly language routine defined 
+  // in switch.s.  You may have to think
+  // a bit to figure out what happens after this, both from the point
+  // of view of the thread and from the perspective of the "outside world".
+
+  SWITCH(oldThread, nextThread);
+
+  // we're back, running oldThread
+
+  // interrupts are off when we return from switch!
+  ASSERT(kernel->interrupt->getLevel() == IntOff);
+
+  DEBUG(dbgThread, "Now in thread: " << oldThread->getName());
+
+  CheckToBeDestroyed();		// check if thread we were running
+                          // before this one has finished
+                          // and needs to be cleaned up
+
+  if (oldThread->space != NULL) {	    // if there is an address space
+    oldThread->RestoreUserState();     // to restore, do it.
+    oldThread->space->RestoreState();
+  }
 }
 
 //----------------------------------------------------------------------
@@ -160,10 +160,10 @@ Scheduler::Run (Thread *nextThread, bool finishing)
 void
 Scheduler::CheckToBeDestroyed()
 {
-    if (toBeDestroyed != NULL) {
-        delete toBeDestroyed;
-	toBeDestroyed = NULL;
-    }
+  if (toBeDestroyed != NULL) {
+    delete toBeDestroyed;
+    toBeDestroyed = NULL;
+  }
 }
  
 //----------------------------------------------------------------------

code/threads/thread.cc

@@ -35,17 +35,17 @@ const int STACK_FENCEPOST = 0xdedbeef;
 
 Thread::Thread(char* threadName, int threadID)
 {
-	ID = threadID;
-    name = threadName;
-    stackTop = NULL;
-    stack = NULL;
-    status = JUST_CREATED;
-    for (int i = 0; i < MachineStateSize; i++) {
-	machineState[i] = NULL;		// not strictly necessary, since
-					// new thread ignores contents 
-					// of machine registers
-    }
-    space = NULL;
+  ID = threadID;
+  name = threadName;
+  stackTop = NULL;
+  stack = NULL;
+  status = JUST_CREATED;
+  for (int i = 0; i < MachineStateSize; i++) {
+    machineState[i] = NULL;		// not strictly necessary, since
+                              // new thread ignores contents 
+                              // of machine registers
+  }
+  space = NULL;
 }
 
 //----------------------------------------------------------------------
@@ -62,10 +62,10 @@ Thread::Thread(char* threadName, int threadID)
 
 Thread::~Thread()
 {
-    DEBUG(dbgThread, "Deleting thread: " << name);
-    ASSERT(this != kernel->currentThread);
-    if (stack != NULL)
-	DeallocBoundedArray((char *) stack, StackSize * sizeof(int));
+  DEBUG(dbgThread, "Deleting thread: " << name);
+  ASSERT(this != kernel->currentThread);
+  if (stack != NULL)
+    DeallocBoundedArray((char *) stack, StackSize * sizeof(int));
 }
 
 //----------------------------------------------------------------------
@@ -91,17 +91,17 @@ Thread::~Thread()
 void 
 Thread::Fork(VoidFunctionPtr func, void *arg)
 {
-    Interrupt *interrupt = kernel->interrupt;
-    Scheduler *scheduler = kernel->scheduler;
-    IntStatus oldLevel;
-    
-    DEBUG(dbgThread, "Forking thread: " << name << " f(a): " << (int) func << " " << arg);
-    StackAllocate(func, arg);
+  Interrupt *interrupt = kernel->interrupt;
+  Scheduler *scheduler = kernel->scheduler;
+  IntStatus oldLevel;
 
-    oldLevel = interrupt->SetLevel(IntOff);
-    scheduler->ReadyToRun(this);	// ReadyToRun assumes that interrupts 
-					// are disabled!
-    (void) interrupt->SetLevel(oldLevel);
+  DEBUG(dbgThread, "Forking thread: " << name << " f(a): " << (int) func << " " << arg);
+  StackAllocate(func, arg);
+
+  oldLevel = interrupt->SetLevel(IntOff);
+  scheduler->ReadyToRun(this);	// ReadyToRun assumes that interrupts 
+                                // are disabled!
+  (void) interrupt->SetLevel(oldLevel);
 }    
 
 //----------------------------------------------------------------------
@@ -122,13 +122,13 @@ Thread::Fork(VoidFunctionPtr func, void *arg)
 void
 Thread::CheckOverflow()
 {
-    if (stack != NULL) {
+  if (stack != NULL) {
 #ifdef HPUX			// Stacks grow upward on the Snakes
-	ASSERT(stack[StackSize - 1] == STACK_FENCEPOST);
+    ASSERT(stack[StackSize - 1] == STACK_FENCEPOST);
 #else
-	ASSERT(*stack == STACK_FENCEPOST);
+    ASSERT(*stack == STACK_FENCEPOST);
 #endif
-   }
+  }
 }
 
 //----------------------------------------------------------------------
@@ -170,12 +170,12 @@ Thread::Begin ()
 void
 Thread::Finish ()
 {
-    (void) kernel->interrupt->SetLevel(IntOff);		
-    ASSERT(this == kernel->currentThread);
-    
-    DEBUG(dbgThread, "Finishing thread: " << name);
-    Sleep(TRUE);				// invokes SWITCH
-    // not reached
+  (void) kernel->interrupt->SetLevel(IntOff);		
+  ASSERT(this == kernel->currentThread);
+
+  DEBUG(dbgThread, "Finishing thread: " << name);
+  Sleep(TRUE);				// invokes SWITCH
+                      // not reached
 }
 
 
@@ -200,19 +200,19 @@ Thread::Finish ()
 void
 Thread::Yield ()
 {
-    Thread *nextThread;
-    IntStatus oldLevel = kernel->interrupt->SetLevel(IntOff);
-    
-    ASSERT(this == kernel->currentThread);
-    
-    DEBUG(dbgThread, "Yielding thread: " << name);
-    
-    nextThread = kernel->scheduler->FindNextToRun();
-    if (nextThread != NULL) {
-	kernel->scheduler->ReadyToRun(this);
-	kernel->scheduler->Run(nextThread, FALSE);
-    }
-    (void) kernel->interrupt->SetLevel(oldLevel);
+  Thread *nextThread;
+  IntStatus oldLevel = kernel->interrupt->SetLevel(IntOff);
+
+  ASSERT(this == kernel->currentThread);
+
+  DEBUG(dbgThread, "Yielding thread: " << name);
+
+  nextThread = kernel->scheduler->FindNextToRun();
+  if (nextThread != NULL) {
+    kernel->scheduler->ReadyToRun(this);
+    kernel->scheduler->Run(nextThread, FALSE);
+  }
+  (void) kernel->interrupt->SetLevel(oldLevel);
 }
 
 //----------------------------------------------------------------------
@@ -238,20 +238,20 @@ Thread::Yield ()
 void
 Thread::Sleep (bool finishing)
 {
-    Thread *nextThread;
-    
-    ASSERT(this == kernel->currentThread);
-    ASSERT(kernel->interrupt->getLevel() == IntOff);
-    
-    DEBUG(dbgThread, "Sleeping thread: " << name);
+  Thread *nextThread;
 
-    status = BLOCKED;
-	//cout << "debug Thread::Sleep " << name << "wait for Idle\n";
-    while ((nextThread = kernel->scheduler->FindNextToRun()) == NULL) {
-		kernel->interrupt->Idle();	// no one to run, wait for an interrupt
-	}    
-    // returns when it's time for us to run
-    kernel->scheduler->Run(nextThread, finishing); 
+  ASSERT(this == kernel->currentThread);
+  ASSERT(kernel->interrupt->getLevel() == IntOff);
+
+  DEBUG(dbgThread, "Sleeping thread: " << name);
+
+  status = BLOCKED;
+  //cout << "debug Thread::Sleep " << name << "wait for Idle\n";
+  while ((nextThread = kernel->scheduler->FindNextToRun()) == NULL) {
+    kernel->interrupt->Idle();	// no one to run, wait for an interrupt
+  }    
+  // returns when it's time for us to run
+  kernel->scheduler->Run(nextThread, finishing); 
 }
 
 //----------------------------------------------------------------------
@@ -262,7 +262,7 @@ Thread::Sleep (bool finishing)
 //	member function.
 //----------------------------------------------------------------------
 
-static void ThreadFinish()    { kernel->currentThread->Finish(); }
+static void ThreadFinish() { kernel->currentThread->Finish(); }
 static void ThreadBegin() { kernel->currentThread->Begin(); }
 void ThreadPrint(Thread *t) { t->Print(); }
 
@@ -277,16 +277,16 @@ void ThreadPrint(Thread *t) { t->Print(); }
 static void *
 PLabelToAddr(void *plabel)
 {
-    int funcPtr = (int) plabel;
+  int funcPtr = (int) plabel;
 
-    if (funcPtr & 0x02) {
-        // L-Field is set.  This is a PLT pointer
-        funcPtr -= 2;	// Get rid of the L bit
-        return (*(void **)funcPtr);
-    } else {
-        // L-field not set.
-        return plabel;
-    }
+  if (funcPtr & 0x02) {
+    // L-Field is set.  This is a PLT pointer
+    funcPtr -= 2;	// Get rid of the L bit
+    return (*(void **)funcPtr);
+  } else {
+    // L-field not set.
+    return plabel;
+  }
 }
 #endif
 
@@ -305,59 +305,59 @@ PLabelToAddr(void *plabel)
 void
 Thread::StackAllocate (VoidFunctionPtr func, void *arg)
 {
-    stack = (int *) AllocBoundedArray(StackSize * sizeof(int));
+  stack = (int *) AllocBoundedArray(StackSize * sizeof(int));
 
 #ifdef PARISC
-    // HP stack works from low addresses to high addresses
-    // everyone else works the other way: from high addresses to low addresses
-    stackTop = stack + 16;	// HP requires 64-byte frame marker
-    stack[StackSize - 1] = STACK_FENCEPOST;
+  // HP stack works from low addresses to high addresses
+  // everyone else works the other way: from high addresses to low addresses
+  stackTop = stack + 16;	// HP requires 64-byte frame marker
+  stack[StackSize - 1] = STACK_FENCEPOST;
 #endif
 
 #ifdef SPARC
-    stackTop = stack + StackSize - 96; 	// SPARC stack must contains at 
-					// least 1 activation record 
-					// to start with.
-    *stack = STACK_FENCEPOST;
+  stackTop = stack + StackSize - 96; 	// SPARC stack must contains at 
+                                      // least 1 activation record 
+                                      // to start with.
+  *stack = STACK_FENCEPOST;
 #endif 
 
 #ifdef PowerPC // RS6000
-    stackTop = stack + StackSize - 16; 	// RS6000 requires 64-byte frame marker
-    *stack = STACK_FENCEPOST;
+  stackTop = stack + StackSize - 16; 	// RS6000 requires 64-byte frame marker
+  *stack = STACK_FENCEPOST;
 #endif 
 
 #ifdef DECMIPS
-    stackTop = stack + StackSize - 4;	// -4 to be on the safe side!
-    *stack = STACK_FENCEPOST;
+  stackTop = stack + StackSize - 4;	// -4 to be on the safe side!
+  *stack = STACK_FENCEPOST;
 #endif
 
 #ifdef ALPHA
-    stackTop = stack + StackSize - 8;	// -8 to be on the safe side!
-    *stack = STACK_FENCEPOST;
+  stackTop = stack + StackSize - 8;	// -8 to be on the safe side!
+  *stack = STACK_FENCEPOST;
 #endif
 
 
 #ifdef x86
-    // the x86 passes the return address on the stack.  In order for SWITCH() 
-    // to go to ThreadRoot when we switch to this thread, the return addres 
-    // used in SWITCH() must be the starting address of ThreadRoot.
-    stackTop = stack + StackSize - 4;	// -4 to be on the safe side!
-    *(--stackTop) = (int) ThreadRoot;
-    *stack = STACK_FENCEPOST;
+  // the x86 passes the return address on the stack.  In order for SWITCH() 
+  // to go to ThreadRoot when we switch to this thread, the return addres 
+  // used in SWITCH() must be the starting address of ThreadRoot.
+  stackTop = stack + StackSize - 4;	// -4 to be on the safe side!
+  *(--stackTop) = (int) ThreadRoot;
+  *stack = STACK_FENCEPOST;
 #endif
-    
+
 #ifdef PARISC
-    machineState[PCState] = PLabelToAddr(ThreadRoot);
-    machineState[StartupPCState] = PLabelToAddr(ThreadBegin);
-    machineState[InitialPCState] = PLabelToAddr(func);
-    machineState[InitialArgState] = arg;
-    machineState[WhenDonePCState] = PLabelToAddr(ThreadFinish);
+  machineState[PCState] = PLabelToAddr(ThreadRoot);
+  machineState[StartupPCState] = PLabelToAddr(ThreadBegin);
+  machineState[InitialPCState] = PLabelToAddr(func);
+  machineState[InitialArgState] = arg;
+  machineState[WhenDonePCState] = PLabelToAddr(ThreadFinish);
 #else
-    machineState[PCState] = (void*)ThreadRoot;
-    machineState[StartupPCState] = (void*)ThreadBegin;
-    machineState[InitialPCState] = (void*)func;
-    machineState[InitialArgState] = (void*)arg;
-    machineState[WhenDonePCState] = (void*)ThreadFinish;
+  machineState[PCState] = (void*)ThreadRoot;
+  machineState[StartupPCState] = (void*)ThreadBegin;
+  machineState[InitialPCState] = (void*)func;
+  machineState[InitialArgState] = (void*)arg;
+  machineState[WhenDonePCState] = (void*)ThreadFinish;
 #endif
 }
 
@@ -391,8 +391,8 @@ Thread::SaveUserState()
 void
 Thread::RestoreUserState()
 {
-    for (int i = 0; i < NumTotalRegs; i++)
-	kernel->machine->WriteRegister(i, userRegisters[i]);
+  for (int i = 0; i < NumTotalRegs; i++)
+    kernel->machine->WriteRegister(i, userRegisters[i]);
 }
 
 

code/userprog/addrspace.cc

@@ -31,32 +31,97 @@
 static void 
 SwapHeader (NoffHeader *noffH)
 {
-    noffH->noffMagic = WordToHost(noffH->noffMagic);
-    noffH->code.size = WordToHost(noffH->code.size);
-    noffH->code.virtualAddr = WordToHost(noffH->code.virtualAddr);
-    noffH->code.inFileAddr = WordToHost(noffH->code.inFileAddr);
+  noffH->noffMagic = WordToHost(noffH->noffMagic);
+  noffH->code.size = WordToHost(noffH->code.size);
+  noffH->code.virtualAddr = WordToHost(noffH->code.virtualAddr);
+  noffH->code.inFileAddr = WordToHost(noffH->code.inFileAddr);
 #ifdef RDATA
-    noffH->readonlyData.size = WordToHost(noffH->readonlyData.size);
-    noffH->readonlyData.virtualAddr = 
-           WordToHost(noffH->readonlyData.virtualAddr);
-    noffH->readonlyData.inFileAddr = 
-           WordToHost(noffH->readonlyData.inFileAddr);
+  noffH->readonlyData.size = WordToHost(noffH->readonlyData.size);
+  noffH->readonlyData.virtualAddr = 
+    WordToHost(noffH->readonlyData.virtualAddr);
+  noffH->readonlyData.inFileAddr = 
+    WordToHost(noffH->readonlyData.inFileAddr);
 #endif 
-    noffH->initData.size = WordToHost(noffH->initData.size);
-    noffH->initData.virtualAddr = WordToHost(noffH->initData.virtualAddr);
-    noffH->initData.inFileAddr = WordToHost(noffH->initData.inFileAddr);
-    noffH->uninitData.size = WordToHost(noffH->uninitData.size);
-    noffH->uninitData.virtualAddr = WordToHost(noffH->uninitData.virtualAddr);
-    noffH->uninitData.inFileAddr = WordToHost(noffH->uninitData.inFileAddr);
+  noffH->initData.size = WordToHost(noffH->initData.size);
+  noffH->initData.virtualAddr = WordToHost(noffH->initData.virtualAddr);
+  noffH->initData.inFileAddr = WordToHost(noffH->initData.inFileAddr);
+  noffH->uninitData.size = WordToHost(noffH->uninitData.size);
+  noffH->uninitData.virtualAddr = WordToHost(noffH->uninitData.virtualAddr);
+  noffH->uninitData.inFileAddr = WordToHost(noffH->uninitData.inFileAddr);
 
 #ifdef RDATA
-    DEBUG(dbgAddr, "code = " << noffH->code.size <<  
-                   " readonly = " << noffH->readonlyData.size <<
-                   " init = " << noffH->initData.size <<
-                   " uninit = " << noffH->uninitData.size << "\n");
+  DEBUG(dbgAddr, "code = " << noffH->code.size <<  
+                 " readonly = " << noffH->readonlyData.size <<
+                 " init = " << noffH->initData.size <<
+                 " uninit = " << noffH->uninitData.size << "\n");
 #endif
 }
 
+FrameTable::Node::Node(int idx):
+  next(nullptr), idx(idx) {}
+
+FrameTable::FrameTable()
+{
+  available = NumPhysPages;
+  useCount = new int[NumPhysPages];
+  begin = end = new FrameTable::Node;
+  for (int i = 0; i < NumPhysPages; i++) {
+    useCount[i] = 0;
+    end->idx = i;
+    end->next = new FrameTable::Node;
+    end = end->next;
+  }
+}
+
+FrameTable::~FrameTable()
+{
+  delete[] useCount;
+  while (begin != end) {
+    FrameTable::Node *tmpNode = begin;
+    begin = begin->next;
+    delete tmpNode;
+  }
+  delete begin;
+}
+
+int FrameTable::Allocate()
+{
+  if (available == 0)
+    return -1;
+
+  int ret = begin->idx;
+  Node *tmp = begin;
+  begin = begin->next;
+  delete tmp;
+
+  --available;
+  useCount[ret]++;
+
+  bzero(kernel->machine->mainMemory + ret * PageSize, PageSize);
+
+  //cerr << "Allocated at page: " << ret << endl;
+  return ret;
+}
+
+void FrameTable::Release(int phyPageNum)
+{
+  useCount[phyPageNum]--;
+
+  if (useCount[phyPageNum] > 0)
+    return;
+
+  ++available;
+
+  //cerr << "Release page: " << end->idx << endl;
+  end->idx = phyPageNum;
+  end->next = new FrameTable::Node;
+}
+
+size_t FrameTable::RemainSize()
+{
+  return available;
+}
+
 //----------------------------------------------------------------------
 // AddrSpace::AddrSpace
 // 	Create an address space to run a user program.
@@ -66,20 +131,7 @@ SwapHeader (NoffHeader *noffH)
 //----------------------------------------------------------------------
 
 AddrSpace::AddrSpace()
-{
-    pageTable = new TranslationEntry[NumPhysPages];
-    for (int i = 0; i < NumPhysPages; i++) {
-	pageTable[i].virtualPage = i;	// for now, virt page # = phys page #
-	pageTable[i].physicalPage = i;
-	pageTable[i].valid = TRUE;
-	pageTable[i].use = FALSE;
-	pageTable[i].dirty = FALSE;
-	pageTable[i].readOnly = FALSE;  
-    }
-    
-    // zero out the entire address space
-    bzero(kernel->machine->mainMemory, MemorySize);
-}
+{}
 
 //----------------------------------------------------------------------
 // AddrSpace::~AddrSpace
@@ -88,7 +140,10 @@ AddrSpace::AddrSpace()
 
 AddrSpace::~AddrSpace()
 {
-   delete pageTable;
+  for (int i = 0; i < NumPhysPages; i++)
+    if (pageTable[i].use == TRUE)
+      kernel->frameTable->Release(pageTable[i].physicalPage);
+  delete[] pageTable;
 }
 
 
@@ -105,72 +160,110 @@ AddrSpace::~AddrSpace()
 bool 
 AddrSpace::Load(char *fileName) 
 {
-    OpenFile *executable = kernel->fileSystem->Open(fileName);
-    NoffHeader noffH;
-    unsigned int size;
+  //cerr << "AddrSpace::Load" << endl;
+  OpenFile *executable = kernel->fileSystem->Open(fileName);
+  NoffHeader noffH;
+  unsigned int size;
 
-    if (executable == NULL) {
-	cerr << "Unable to open file " << fileName << "\n";
-	return FALSE;
-    }
+  if (executable == NULL) {
+    cerr << "Unable to open file " << fileName << "\n";
+    return FALSE;
+  }
 
-    executable->ReadAt((char *)&noffH, sizeof(noffH), 0);
-    if ((noffH.noffMagic != NOFFMAGIC) && 
-		(WordToHost(noffH.noffMagic) == NOFFMAGIC))
-    	SwapHeader(&noffH);
-    ASSERT(noffH.noffMagic == NOFFMAGIC);
+  executable->ReadAt((char *)&noffH, sizeof(noffH), 0);
+  if ((noffH.noffMagic != NOFFMAGIC) && 
+    (WordToHost(noffH.noffMagic) == NOFFMAGIC))
+    SwapHeader(&noffH);
+  ASSERT(noffH.noffMagic == NOFFMAGIC);
 
 #ifdef RDATA
 // how big is address space?
-    size = noffH.code.size + noffH.readonlyData.size + noffH.initData.size +
-           noffH.uninitData.size + UserStackSize;	
-                                                // we need to increase the size
-						// to leave room for the stack
+  size = noffH.code.size + noffH.readonlyData.size + noffH.initData.size +
+    noffH.uninitData.size + UserStackSize;	
+  //cerr << noffH.code.size << ' ' 
+  //     << noffH.readonlyData.size << ' '
+  //     << noffH.initData.size << ' '
+  //     << noffH.uninitData.size << ' '
+  //     << UserStackSize << endl;
+  // we need to increase the size
+  // to leave room for the stack
 #else
 // how big is address space?
-    size = noffH.code.size + noffH.initData.size + noffH.uninitData.size 
-			+ UserStackSize;	// we need to increase the size
-						// to leave room for the stack
+  size = noffH.code.size + noffH.initData.size + noffH.uninitData.size 
+    + UserStackSize;	// we need to increase the size
+          // to leave room for the stack
+  //cerr << noffH.code.size << ' ' 
+  //     << noffH.initData.size << ' '
+  //     << noffH.uninitData.size << ' '
+  //     << UserStackSize << endl;
 #endif
-    numPages = divRoundUp(size, PageSize);
-    size = numPages * PageSize;
+  numPages = divRoundUp(size, PageSize);
+  size = numPages * PageSize;
 
-    ASSERT(numPages <= NumPhysPages);		// check we're not trying
-						// to run anything too big --
-						// at least until we have
-						// virtual memory
+  ASSERT(numPages <= NumPhysPages);		// check we're not trying
+          // to run anything too big --
+          // at least until we have
+          // virtual memory
+  
+  pageTable = new TranslationEntry[numPages];
+  for (int i = 0; i < numPages; i++) {
+    pageTable[i].virtualPage = i;
+    pageTable[i].physicalPage = -1;
+    pageTable[i].valid = TRUE;
+    pageTable[i].use = FALSE;
+    pageTable[i].dirty = FALSE;
+    pageTable[i].readOnly = FALSE;
+  }
 
-    DEBUG(dbgAddr, "Initializing address space: " << numPages << ", " << size);
+  DEBUG(dbgAddr, "Initializing address space: " << numPages << ", " << size);
 
 // then, copy in the code and data segments into memory
-// Note: this code assumes that virtual address = physical address
-    if (noffH.code.size > 0) {
-        DEBUG(dbgAddr, "Initializing code segment.");
-	DEBUG(dbgAddr, noffH.code.virtualAddr << ", " << noffH.code.size);
-        executable->ReadAt(
-		&(kernel->machine->mainMemory[noffH.code.virtualAddr]), 
-			noffH.code.size, noffH.code.inFileAddr);
+  if (noffH.code.size > 0) {
+    DEBUG(dbgAddr, "Initializing code segment.");
+    DEBUG(dbgAddr, noffH.code.virtualAddr << ", " << noffH.code.size);
+
+    for (size_t cur = 0; cur < (size_t)noffH.code.size; cur += PageSize) {
+      size_t physAddr, size = min((size_t)PageSize, noffH.code.size - cur);
+      Translate(noffH.code.virtualAddr + cur, &physAddr, 1);
+      //cerr << "physAddr, size: " << physAddr << ' ' << size << endl;
+
+      executable->ReadAt(
+        &(kernel->machine->mainMemory[physAddr]), size,
+        noffH.code.inFileAddr + cur);
     }
-    if (noffH.initData.size > 0) {
-        DEBUG(dbgAddr, "Initializing data segment.");
-	DEBUG(dbgAddr, noffH.initData.virtualAddr << ", " << noffH.initData.size);
-        executable->ReadAt(
-		&(kernel->machine->mainMemory[noffH.initData.virtualAddr]),
-			noffH.initData.size, noffH.initData.inFileAddr);
+  }
+  if (noffH.initData.size > 0) {
+    DEBUG(dbgAddr, "Initializing data segment.");
+    DEBUG(dbgAddr, noffH.initData.virtualAddr << ", " << noffH.initData.size);
+
+    for (size_t cur = 0; cur < (size_t)noffH.initData.size; cur += PageSize) {
+      size_t physAddr, size = min((size_t)PageSize, noffH.initData.size - cur);
+      Translate(noffH.initData.virtualAddr + cur, &physAddr, 1);
+
+      executable->ReadAt(
+        &(kernel->machine->mainMemory[physAddr]), size,
+        noffH.initData.inFileAddr + cur);
     }
+  }
 
 #ifdef RDATA
-    if (noffH.readonlyData.size > 0) {
-        DEBUG(dbgAddr, "Initializing read only data segment.");
-	DEBUG(dbgAddr, noffH.readonlyData.virtualAddr << ", " << noffH.readonlyData.size);
-        executable->ReadAt(
-		&(kernel->machine->mainMemory[noffH.readonlyData.virtualAddr]),
-			noffH.readonlyData.size, noffH.readonlyData.inFileAddr);
+  if (noffH.readonlyData.size > 0) {
+    DEBUG(dbgAddr, "Initializing read only data segment.");
+    DEBUG(dbgAddr, noffH.readonlyData.virtualAddr << ", " << noffH.readonlyData.size);
+
+    for (size_t cur = 0; cur < (size_t)noffH.readonlyData.size; cur += PageSize) {
+      size_t physAddr, size = min((size_t)PageSize, noffH.readonlyData.size - cur);
+      Translate(noffH.readonlyData.virtualAddr + cur, &physAddr, 1);
+
+      executable->ReadAt(
+        &(kernel->machine->mainMemory[physAddr]),
+        size, noffH.readonlyData.inFileAddr + cur);
     }
+  }
 #endif
 
-    delete executable;			// close file
-    return TRUE;			// success
+  delete executable;			// close file
+  return TRUE;			// success
 }
 
 //----------------------------------------------------------------------
@@ -185,17 +278,17 @@ AddrSpace::Load(char *fileName)
 void 
 AddrSpace::Execute(char* fileName) 
 {
+  //cerr << "AddrSpace::Execute" << endl;
+  kernel->currentThread->space = this;
 
-    kernel->currentThread->space = this;
+  this->InitRegisters();		// set the initial register values
+  this->RestoreState();		// load page table register
 
-    this->InitRegisters();		// set the initial register values
-    this->RestoreState();		// load page table register
+  kernel->machine->Run();		// jump to the user progam
 
-    kernel->machine->Run();		// jump to the user progam
-
-    ASSERTNOTREACHED();			// machine->Run never returns;
-					// the address space exits
-					// by doing the syscall "exit"
+  ASSERTNOTREACHED();			// machine->Run never returns;
+        // the address space exits
+        // by doing the syscall "exit"
 }
 
 
@@ -212,27 +305,27 @@ AddrSpace::Execute(char* fileName)
 void
 AddrSpace::InitRegisters()
 {
-    Machine *machine = kernel->machine;
-    int i;
+  Machine *machine = kernel->machine;
+  int i;
 
-    for (i = 0; i < NumTotalRegs; i++)
-	machine->WriteRegister(i, 0);
+  for (i = 0; i < NumTotalRegs; i++)
+    machine->WriteRegister(i, 0);
 
-    // Initial program counter -- must be location of "Start", which
-    //  is assumed to be virtual address zero
-    machine->WriteRegister(PCReg, 0);	
+  // Initial program counter -- must be location of "Start", which
+  //  is assumed to be virtual address zero
+  machine->WriteRegister(PCReg, 0);	
 
-    // Need to also tell MIPS where next instruction is, because
-    // of branch delay possibility
-    // Since instructions occupy four bytes each, the next instruction
-    // after start will be at virtual address four.
-    machine->WriteRegister(NextPCReg, 4);
+  // Need to also tell MIPS where next instruction is, because
+  // of branch delay possibility
+  // Since instructions occupy four bytes each, the next instruction
+  // after start will be at virtual address four.
+  machine->WriteRegister(NextPCReg, 4);
 
-   // Set the stack register to the end of the address space, where we
-   // allocated the stack; but subtract off a bit, to make sure we don't
-   // accidentally reference off the end!
-    machine->WriteRegister(StackReg, numPages * PageSize - 16);
-    DEBUG(dbgAddr, "Initializing stack pointer: " << numPages * PageSize - 16);
+ // Set the stack register to the end of the address space, where we
+ // allocated the stack; but subtract off a bit, to make sure we don't
+ // accidentally reference off the end!
+  machine->WriteRegister(StackReg, numPages * PageSize - 16);
+  DEBUG(dbgAddr, "Initializing stack pointer: " << numPages * PageSize - 16);
 }
 
 //----------------------------------------------------------------------
@@ -256,8 +349,8 @@ void AddrSpace::SaveState()
 
 void AddrSpace::RestoreState() 
 {
-    kernel->machine->pageTable = pageTable;
-    kernel->machine->pageTableSize = numPages;
+  kernel->machine->pageTable = pageTable;
+  kernel->machine->pageTableSize = numPages;
 }
 
 
@@ -272,45 +365,48 @@ void AddrSpace::RestoreState()
 ExceptionType
 AddrSpace::Translate(unsigned int vaddr, unsigned int *paddr, int isReadWrite)
 {
-    TranslationEntry *pte;
-    int               pfn;
-    unsigned int      vpn    = vaddr / PageSize;
-    unsigned int      offset = vaddr % PageSize;
+  TranslationEntry *pte;
+  int               pfn;
+  unsigned int      vpn    = vaddr / PageSize;
+  unsigned int      offset = vaddr % PageSize;
 
-    if(vpn >= numPages) {
-        return AddressErrorException;
+  if(vpn >= numPages) {
+    return AddressErrorException;
+  }
+
+  pte = &pageTable[vpn];
+
+  if(isReadWrite && pte->readOnly) {
+    return ReadOnlyException;
+  }
+
+  pfn = pte->physicalPage;
+  if (pfn == -1) {
+    pfn = pte->physicalPage = kernel->frameTable->Allocate();
+    if (pfn == -1) {
+      DEBUG(dbgAddr, "Memory Limit exceeded");
+      return MemoryLimitException;
     }
+  }
 
-    pte = &pageTable[vpn];
+  // if the pageFrame is too big, there is something really wrong!
+  // An invalid translation was loaded into the page table or TLB.
+  if (pfn >= NumPhysPages) {
+    DEBUG(dbgAddr, "Illegal physical page " << pfn);
+    return BusErrorException;
+  }
 
-    if(isReadWrite && pte->readOnly) {
-        return ReadOnlyException;
-    }
+  pte->use = TRUE;          // set the use, dirty bits
 
-    pfn = pte->physicalPage;
+  if(isReadWrite)
+    pte->dirty = TRUE;
 
-    // if the pageFrame is too big, there is something really wrong!
-    // An invalid translation was loaded into the page table or TLB.
-    if (pfn >= NumPhysPages) {
-        DEBUG(dbgAddr, "Illegal physical page " << pfn);
-        return BusErrorException;
-    }
+  *paddr = pfn * PageSize + offset;
 
-    pte->use = TRUE;          // set the use, dirty bits
+  ASSERT((*paddr < MemorySize));
 
-    if(isReadWrite)
-        pte->dirty = TRUE;
+  //cerr << " -- AddrSpace::Translate(): vaddr: " << vaddr <<
+  //  ", paddr: " << *paddr << "\n";
 
-    *paddr = pfn*PageSize + offset;
-
-    ASSERT((*paddr < MemorySize));
-
-    //cerr << " -- AddrSpace::Translate(): vaddr: " << vaddr <<
-    //  ", paddr: " << *paddr << "\n";
-
-    return NoException;
+  return NoException;
 }
-
-
-
-

code/userprog/addrspace.h

@@ -18,6 +18,28 @@
 
 #define UserStackSize		1024 	// increase this as necessary!
 
+class FrameTable {
+  public:
+    FrameTable();
+    ~FrameTable();
+
+    int Allocate();
+    void Release(int phyPageNum);
+    size_t RemainSize();
+
+  private:
+    struct Node {
+      Node *next;
+      int idx;
+      Node(int idx = -1);
+    };
+
+    Node *begin, *end;
+
+    size_t available;
+    int *useCount;
+};
+
 class AddrSpace {
   public:
     AddrSpace();			// Create an address space.
@@ -40,8 +62,7 @@ class AddrSpace {
     ExceptionType Translate(unsigned int vaddr, unsigned int *paddr, int mode);
 
   private:
-    TranslationEntry *pageTable;	// Assume linear page table translation
-					// for now!
+    TranslationEntry *pageTable;
     unsigned int numPages;		// Number of pages in the virtual 
 					// address space
 

code/userprog/exception.cc

@@ -1,18 +1,18 @@
 // exception.cc 
-//	Entry point into the Nachos kernel from user programs.
-//	There are two kinds of things that can cause control to
-//	transfer back to here from user code:
+//  Entry point into the Nachos kernel from user programs.
+//  There are two kinds of things that can cause control to
+//  transfer back to here from user code:
 //
-//	syscall -- The user code explicitly requests to call a procedure
-//	in the Nachos kernel.  Right now, the only function we support is
-//	"Halt".
+//  syscall -- The user code explicitly requests to call a procedure
+//  in the Nachos kernel.  Right now, the only function we support is
+//  "Halt".
 //
-//	exceptions -- The user code does something that the CPU can't handle.
-//	For instance, accessing memory that doesn't exist, arithmetic errors,
-//	etc.  
+//  exceptions -- The user code does something that the CPU can't handle.
+//  For instance, accessing memory that doesn't exist, arithmetic errors,
+//  etc.  
 //
-//	Interrupts (which can also cause control to transfer from user
-//	code into the Nachos kernel) are handled elsewhere.
+//  Interrupts (which can also cause control to transfer from user
+//  code into the Nachos kernel) are handled elsewhere.
 //
 // For now, this only handles the Halt() system call.
 // Everything else core dumps.
@@ -27,106 +27,192 @@
 #include "ksyscall.h"
 //----------------------------------------------------------------------
 // ExceptionHandler
-// 	Entry point into the Nachos kernel.  Called when a user program
-//	is executing, and either does a syscall, or generates an addressing
-//	or arithmetic exception.
+//   Entry point into the Nachos kernel.  Called when a user program
+//  is executing, and either does a syscall, or generates an addressing
+//  or arithmetic exception.
 //
-// 	For system calls, the following is the calling convention:
+//   For system calls, the following is the calling convention:
 //
-// 	system call code -- r2
-//		arg1 -- r4
-//		arg2 -- r5
-//		arg3 -- r6
-//		arg4 -- r7
+//   system call code -- r2
+//  	arg1 -- r4
+//  	arg2 -- r5
+//  	arg3 -- r6
+//  	arg4 -- r7
 //
-//	The result of the system call, if any, must be put back into r2. 
+//  The result of the system call, if any, must be put back into r2. 
 //
 // If you are handling a system call, don't forget to increment the pc
 // before returning. (Or else you'll loop making the same system call forever!)
 //
-//	"which" is the kind of exception.  The list of possible exceptions 
-//	is in machine.h.
+//  "which" is the kind of exception.  The list of possible exceptions 
+//  is in machine.h.
 //----------------------------------------------------------------------
 
 void
 ExceptionHandler(ExceptionType which)
 {
-    int type = kernel->machine->ReadRegister(2);
-	int val;
-    int status, exit, threadID, programID;
-	DEBUG(dbgSys, "Received Exception " << which << " type: " << type << "\n");
-    switch (which) {
+  int type = kernel->machine->ReadRegister(2);
+  int val;
+  int status, exit, threadID, programID;
+  DEBUG(dbgSys, "Received Exception " << which << " type: " << type << "\n");
+  switch (which) {
     case SyscallException:
-      	switch(type) {
-      	case SC_Halt:
-			DEBUG(dbgSys, "Shutdown, initiated by user program.\n");
-			SysHalt();
-                        cout<<"in exception\n";
-			ASSERTNOTREACHED();
-			break;
-		case SC_MSG:
-			DEBUG(dbgSys, "Message received.\n");
-			val = kernel->machine->ReadRegister(4);
-			{
-			char *msg = &(kernel->machine->mainMemory[val]);
-			cout << msg << endl;
-			}
-			SysHalt();
-			ASSERTNOTREACHED();
-			break;
-		case SC_Create:
-			val = kernel->machine->ReadRegister(4);
-			{
-			char *filename = &(kernel->machine->mainMemory[val]);
-			//cout << filename << endl;
-			status = SysCreate(filename);
-			kernel->machine->WriteRegister(2, (int) status);
-			}
-			kernel->machine->WriteRegister(PrevPCReg, kernel->machine->ReadRegister(PCReg));
-			kernel->machine->WriteRegister(PCReg, kernel->machine->ReadRegister(PCReg) + 4);
-			kernel->machine->WriteRegister(NextPCReg, kernel->machine->ReadRegister(PCReg)+4);
-			return;
-			ASSERTNOTREACHED();
-            break;
-      	case SC_Add:
-			DEBUG(dbgSys, "Add " << kernel->machine->ReadRegister(4) << " + " << kernel->machine->ReadRegister(5) << "\n");
-			/* Process SysAdd Systemcall*/
-			int result;
-			result = SysAdd(/* int op1 */(int)kernel->machine->ReadRegister(4),
-			/* int op2 */(int)kernel->machine->ReadRegister(5));
-			DEBUG(dbgSys, "Add returning with " << result << "\n");
-			/* Prepare Result */
-			kernel->machine->WriteRegister(2, (int)result);	
-			/* Modify return point */
-			{
-	  		/* set previous programm counter (debugging only)*/
-	  		kernel->machine->WriteRegister(PrevPCReg, kernel->machine->ReadRegister(PCReg));
-	  			
-			/* set programm counter to next instruction (all Instructions are 4 byte wide)*/
-	  		kernel->machine->WriteRegister(PCReg, kernel->machine->ReadRegister(PCReg) + 4);
-	  
-	 		/* set next programm counter for brach execution */
-	 		kernel->machine->WriteRegister(NextPCReg, kernel->machine->ReadRegister(PCReg)+4);
-			}
-			cout << "result is " << result << "\n";	
-			return;	
-			ASSERTNOTREACHED();
-            break;
-		case SC_Exit:
-			DEBUG(dbgAddr, "Program exit\n");
-            val=kernel->machine->ReadRegister(4);
-            cout << "return value:" << val << endl;
-			kernel->currentThread->Finish();
-            break;
-      	default:
-			cerr << "Unexpected system call " << type << "\n";
-			break;
-		}
-		break;
-	default:
-		cerr << "Unexpected user mode exception " << (int)which << "\n";
-		break;
-    }
-    ASSERTNOTREACHED();
+      switch(type) {
+        case SC_Halt:
+  		    DEBUG(dbgSys, "Shutdown, initiated by user program.\n");
+  		    SysHalt();
+          cout<<"in exception\n";
+          ASSERTNOTREACHED();
+          break;
+  	    case SC_MSG:
+          DEBUG(dbgSys, "Message received.\n");
+          val = kernel->machine->ReadRegister(4);
+          {
+            char *msg = &(kernel->machine->mainMemory[val]);
+            cout << msg << endl;
+          }
+          SysHalt();
+          ASSERTNOTREACHED();
+          break;
+        case SC_Create:
+          val = kernel->machine->ReadRegister(4);
+          {
+            char *filename = &(kernel->machine->mainMemory[val]);
+            //cout << filename << endl;
+            status = SysCreate(filename);
+            kernel->machine->WriteRegister(2, (int) status);
+          }
+          kernel->machine->WriteRegister(PrevPCReg, kernel->machine->ReadRegister(PCReg));
+          kernel->machine->WriteRegister(PCReg, kernel->machine->ReadRegister(PCReg) + 4);
+          kernel->machine->WriteRegister(NextPCReg, kernel->machine->ReadRegister(PCReg) + 4);
+          return;
+          ASSERTNOTREACHED();
+          break;
+        case SC_Add:
+          DEBUG(dbgSys, "Add " << kernel->machine->ReadRegister(4) << " + " << kernel->machine->ReadRegister(5) << "\n");
+          /* Process SysAdd Systemcall*/
+          int result;
+          result = SysAdd(/* int op1 */(int)kernel->machine->ReadRegister(4),
+          /* int op2 */(int)kernel->machine->ReadRegister(5));
+          DEBUG(dbgSys, "Add returning with " << result << "\n");
+          /* Prepare Result */
+          kernel->machine->WriteRegister(2, (int)result);	
+          /* Modify return point */
+          {
+            /* set previous programm counter (debugging only)*/
+            kernel->machine->WriteRegister(PrevPCReg, kernel->machine->ReadRegister(PCReg));
+              
+            /* set programm counter to next instruction (all Instructions are 4 byte wide)*/
+            kernel->machine->WriteRegister(PCReg, kernel->machine->ReadRegister(PCReg) + 4);
+        
+            /* set next programm counter for brach execution */
+            kernel->machine->WriteRegister(NextPCReg, kernel->machine->ReadRegister(PCReg) + 4);
+          }
+          cout << "result is " << result << "\n";	
+          return;	
+          ASSERTNOTREACHED();
+          break;
+        case SC_Exit:
+          DEBUG(dbgAddr, "Program exit\n");
+          val = kernel->machine->ReadRegister(4);
+          cout << "return value:" << val << endl;
+          kernel->currentThread->Finish();
+          break;
+        case SC_PrintInt:
+          DEBUG(dbgAddr, "Printing int\n");
+          val = (int)kernel->machine->ReadRegister(4);
+          SysPrintInt(val);
+
+          kernel->machine->WriteRegister(PrevPCReg, kernel->machine->ReadRegister(PCReg));
+          kernel->machine->WriteRegister(PCReg, kernel->machine->ReadRegister(PCReg) + 4);
+          kernel->machine->WriteRegister(NextPCReg, kernel->machine->ReadRegister(PCReg) + 4);
+          
+          return;
+          ASSERTNOTREACHED();
+          break;
+        case SC_Open:
+          DEBUG(dbgAddr, "Open file\n");
+
+          {
+            val = kernel->machine->ReadRegister(4);
+            char *name = &(kernel->machine->mainMemory[val]);
+            OpenFileId ret = SysOpen(name);
+            kernel->machine->WriteRegister(2, ret);
+          }
+ 
+          kernel->machine->WriteRegister(PrevPCReg, kernel->machine->ReadRegister(PCReg));
+          kernel->machine->WriteRegister(PCReg, kernel->machine->ReadRegister(PCReg) + 4);
+          kernel->machine->WriteRegister(NextPCReg, kernel->machine->ReadRegister(PCReg) + 4);
+
+          return;
+          ASSERTNOTREACHED();
+          break;
+        case SC_Read:
+          DEBUG(dbgAddr, "Read file\n");
+
+          {
+            val = kernel->machine->ReadRegister(4);
+            char *buffer = &(kernel->machine->mainMemory[val]);
+            int size = kernel->machine->ReadRegister(5);
+            OpenFileId id = (OpenFileId)kernel->machine->ReadRegister(6);
+            int ret = SysRead(buffer, size, id);
+            kernel->machine->WriteRegister(2, ret);
+          }
+
+          kernel->machine->WriteRegister(PrevPCReg, kernel->machine->ReadRegister(PCReg));
+          kernel->machine->WriteRegister(PCReg, kernel->machine->ReadRegister(PCReg) + 4);
+          kernel->machine->WriteRegister(NextPCReg, kernel->machine->ReadRegister(PCReg) + 4);
+
+          return;
+          ASSERTNOTREACHED();
+          break;
+        case SC_Write:
+          DEBUG(dbgAddr, "Write file\n");
+
+          {
+            val = kernel->machine->ReadRegister(4);
+            char *buffer = &(kernel->machine->mainMemory[val]);
+            int size = kernel->machine->ReadRegister(5);
+            OpenFileId id = (OpenFileId)kernel->machine->ReadRegister(6);
+            // fprintf(stderr, "buffer: %p\n", buffer);
+            // cerr << "size: " << size << endl;
+            // cerr << "id: " << id << endl;
+            int ret = SysWrite(buffer, size, id);
+            kernel->machine->WriteRegister(2, ret);
+          }
+
+          kernel->machine->WriteRegister(PrevPCReg, kernel->machine->ReadRegister(PCReg));
+          kernel->machine->WriteRegister(PCReg, kernel->machine->ReadRegister(PCReg) + 4);
+          kernel->machine->WriteRegister(NextPCReg, kernel->machine->ReadRegister(PCReg) + 4);
+
+          return;
+          ASSERTNOTREACHED();
+          break;
+        case SC_Close:
+          DEBUG(dbgAddr, "Close file\n");
+
+          {
+            OpenFileId id = (OpenFileId)kernel->machine->ReadRegister(4);
+            int ret = SysClose(id);
+            kernel->machine->WriteRegister(2, ret);
+          }
+
+          kernel->machine->WriteRegister(PrevPCReg, kernel->machine->ReadRegister(PCReg));
+          kernel->machine->WriteRegister(PCReg, kernel->machine->ReadRegister(PCReg) + 4);
+          kernel->machine->WriteRegister(NextPCReg, kernel->machine->ReadRegister(PCReg) + 4);
+
+          return;
+          ASSERTNOTREACHED();
+          break;
+        default:
+          cerr << "Unexpected system call " << type << "\n";
+          break;
+  	  }
+  	  break;
+    default:
+      cerr << "Unexpected user mode exception " << (int)which << "\n";
+      break;
+  }
+  ASSERTNOTREACHED();
 }
 

code/userprog/ksyscall.h

@@ -1,38 +1,78 @@
-/**************************************************************
- *
- * userprog/ksyscall.h
- *
- * Kernel interface for systemcalls 
- *
- * by Marcus Voelp  (c) Universitaet Karlsruhe
- *
- **************************************************************/
-
-#ifndef __USERPROG_KSYSCALL_H__ 
-#define __USERPROG_KSYSCALL_H__ 
-
-#include "kernel.h"
-
-#include "synchconsole.h"
-
-
-void SysHalt()
-{
-  kernel->interrupt->Halt();
-}
-
-int SysAdd(int op1, int op2)
-{
-  return op1 + op2;
-}
-
-int SysCreate(char *filename)
-{
-	// return value
-	// 1: success
-	// 0: failed
-	return kernel->interrupt->CreateFile(filename);
-}
-
-
-#endif /* ! __USERPROG_KSYSCALL_H__ */
+/**************************************************************
+ *
+ * userprog/ksyscall.h
+ *
+ * Kernel interface for systemcalls 
+ *
+ * by Marcus Voelp  (c) Universitaet Karlsruhe
+ *
+ **************************************************************/
+
+#ifndef __USERPROG_KSYSCALL_H__ 
+#define __USERPROG_KSYSCALL_H__ 
+
+#define INT_BUF_LENGTH 13
+
+#include "kernel.h"
+
+#include "synchconsole.h"
+
+
+void SysHalt()
+{
+  kernel->interrupt->Halt();
+}
+
+int SysAdd(int op1, int op2)
+{
+  return op1 + op2;
+}
+
+int SysCreate(char *filename)
+{
+  // return value
+  // 1: success
+  // 0: failed
+  return kernel->interrupt->CreateFile(filename);
+}
+
+void SysPrintInt(int value) {
+  kernel->interrupt->PrintInt(value);
+}
+
+OpenFileId SysOpen(char *name) {
+  OpenFileId id = -1;
+  for (int i = 0; i < 20; i++)
+    if (kernel->fileSystem->fileDescriptorTable[i] == NULL) {
+      id = i;
+      kernel->fileSystem->fileDescriptorTable[i] 
+        = kernel->fileSystem->Open(name);
+      if (kernel->fileSystem->fileDescriptorTable[i] == NULL)
+        return -1;
+      break;
+    }
+  return id;
+}
+
+int SysWrite(char *buffer, int size, OpenFileId id) {
+  if (id < 0 || id >= 20 || kernel->fileSystem->fileDescriptorTable[id] == NULL)
+    return -1;
+  return kernel->fileSystem->fileDescriptorTable[id]->Write(buffer, size);
+}
+
+int SysRead(char *buffer, int size, OpenFileId id) {
+  if (id < 0 || id >= 20 || kernel->fileSystem->fileDescriptorTable[id] == NULL)
+    return -1;
+  return kernel->fileSystem->fileDescriptorTable[id]->Read(buffer, size);
+}
+
+int SysClose(OpenFileId id) {
+  if (id < 0 || id >= 20 || kernel->fileSystem->fileDescriptorTable[id] == NULL)
+    return 0;
+  delete kernel->fileSystem->fileDescriptorTable[id];
+  kernel->fileSystem->fileDescriptorTable[id] = NULL;
+  return 1;
+}
+
+
+#endif /* ! __USERPROG_KSYSCALL_H__ */

code/userprog/synchconsole.cc

@@ -106,6 +106,15 @@ SynchConsoleOutput::PutChar(char ch)
     lock->Release();
 }
 
+void
+SynchConsoleOutput::PutInt(int value)
+{
+  lock->Acquire();
+  consoleOutput->PutInt(value);
+  waitFor->P();
+  lock->Release();
+}
+
 //----------------------------------------------------------------------
 // SynchConsoleOutput::CallBack
 //      Interrupt handler called when it's safe to send the next 

code/userprog/synchconsole.h

@@ -41,6 +41,7 @@ class SynchConsoleOutput : public CallBackObj {
     ~SynchConsoleOutput();
 
     void PutChar(char ch);	// Write a character, waiting if necessary
+    void PutInt(int value);
    
   private:
     ConsoleOutput *consoleOutput;// the hardware display

code/userprog/syscall.h

@@ -23,19 +23,22 @@
 #define SC_Exec		2
 #define SC_Join		3
 #define SC_Create	4
-#define SC_Remove       5
+#define SC_Remove 5
 #define SC_Open		6
 #define SC_Read		7
 #define SC_Write	8
-#define SC_Seek         9
-#define SC_Close	10
-#define SC_ThreadFork	11
+#define SC_Seek   9
+#define SC_Close	      10
+#define SC_ThreadFork	  11
 #define SC_ThreadYield	12
-#define SC_ExecV	13
+#define SC_ExecV        13
 #define SC_ThreadExit   14
 #define SC_ThreadJoin   15
-#define SC_Add		42
-#define SC_MSG		100
+
+#define SC_PrintInt     16
+
+#define SC_Add		      42
+#define SC_MSG	        100
 
 #ifndef IN_ASM
 
@@ -109,7 +112,7 @@ typedef int OpenFileId;
  */
 
 #define SysConsoleInput	0  
-#define SysConsoleOutput	1  
+#define SysConsoleOutput 1  
  
 /* Create a Nachos file, with name "name" */
 /* Note: Create does not open the file.   */
@@ -175,7 +178,9 @@ int ThreadJoin(ThreadId id);
 /*
  * Deletes current thread and returns ExitCode to every waiting lokal thread.
  */
-void ThreadExit(int ExitCode);	
+void ThreadExit(int ExitCode);
+
+void PrintInt(int number);
 
 #endif /* IN_ASM */
 

docker-compose.yaml

@@ -0,0 +1,7 @@
+---
+services:
+  test:
+    build: .
+    user: '60139:60139'
+    volumes:
+      - './:/work'