Chore: update README.md

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 @@
+# Introduction to OS 2024 HW
+
+## 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

@@ -200,18 +200,18 @@ 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
+CFLAGS = -g -Wall $(INCPATH) $(DEFINES) $(HOSTCFLAGS) -DCHANGED -m32 -w
 LDFLAGS = -m32
 CPP_AS_FLAGS= -m32
 
 #####################################################################
 CPP=/lib/cpp
-CC = g++ -m32 -Wno-deprecated
+CC = g++ -m32
-LD = g++ -m32 -Wno-deprecated
+LD = g++ -m32
 AS = as --32
 RM = /bin/rm
 
-INCPATH = -I../network -I../filesys -I../userprog -I../threads -I../machine -I../lib -I-
+INCPATH = -iquote../network -iquote../filesys -iquote../userprog -iquote../threads -iquote../machine -iquote../lib
 
 PROGRAM = nachos
 

code/filesys/filesys.h

@@ -40,13 +40,15 @@
 #ifdef FILESYS_STUB 		// Temporarily implement file system calls as 
 				// calls to UNIX, until the real file system
 				// implementation is available
+
+typedef int OpenFileId;
+
 class FileSystem {
 public:
 	FileSystem() { for (int i = 0; i < 20; i++) fileDescriptorTable[i] = NULL; }
 
 	bool Create(char* name) {
 		int fileDescriptor = OpenForWrite(name);
-
 		if (fileDescriptor == -1) return FALSE;
 		Close(fileDescriptor);
 		return TRUE;
@@ -54,11 +56,60 @@ class FileSystem {
 
 	OpenFile* Open(char* name) {
 		int fileDescriptor = OpenForReadWrite(name, FALSE);
-
 		if (fileDescriptor == -1) return NULL;
 		return new OpenFile(fileDescriptor);
 	}
 
+	OpenFileId OpenFiles(char* name) {
+		OpenFile* file = Open(name);
+		if (!file) return -1;
+		int freeIndex = -1;
+
+		for (int i = 0; i < 20; i++)
+			if (!fileDescriptorTable[i])
+				freeIndex = i;
+
+		if (freeIndex == -1)
+			return -1;
+		OpenFileId fileDescriptor = file->GetFileDescriptor();
+		fileDescriptorTable[freeIndex] = file;
+		return fileDescriptor;
+	}
+
+	int WriteFile(char* buffer, int size, OpenFileId fd) {
+		for (int i = 0; i < 20; i++) {
+			if (!fileDescriptorTable[i])
+				continue;
+			if (fileDescriptorTable[i]->GetFileDescriptor() == fd) {
+				return fileDescriptorTable[i]->Write(buffer, size);
+			}
+		}
+		return -1;
+	}
+
+	int ReadFile(char* buffer, int size, OpenFileId fd) {
+		for (int i = 0; i < 20; i++) {
+			if (!fileDescriptorTable[i])
+				continue;
+			if (fileDescriptorTable[i]->GetFileDescriptor() == fd)
+				return fileDescriptorTable[i]->Read(buffer, size);
+		}
+		return -1;
+	}
+
+	int CloseFile(OpenFileId fd) {
+		for (int i = 0; i < 20; i++) {
+			if (!fileDescriptorTable[i])
+				continue;
+			if (fileDescriptorTable[i]->GetFileDescriptor() == fd) {
+				delete fileDescriptorTable[i];
+				fileDescriptorTable[i] = NULL;
+				return 1;
+			}
+		}
+		return 0;
+	}
+
 	bool Remove(char* name) { return Unlink(name) == 0; }
 
 	OpenFile* fileDescriptorTable[20];

code/filesys/openfile.h

@@ -27,6 +27,8 @@
 #ifdef FILESYS_STUB			// Temporarily implement calls to 
 					// Nachos file system as calls to UNIX!
 					// See definitions listed under #else
+typedef int OpenFileId;
+
 class OpenFile {
   public:
     OpenFile(int f) { file = f; currentOffset = 0; }	// open the file
@@ -54,6 +56,10 @@ class OpenFile {
 
     int Length() { Lseek(file, 0, 2); return Tell(file); }
 
+	OpenFileId GetFileDescriptor() {
+		return file;
+	}
+    
   private:
     int file;
     int currentOffset;

code/lib/debug.h

@@ -29,6 +29,7 @@ const char dbgFile = 'f'; 		// file system
 const char dbgAddr = 'a'; 		// address spaces
 const char dbgNet = 'n'; 		// network emulation
 const char dbgSys = 'u';                // systemcall
+const char dbgSche = 'z';
 
 class Debug {
   public:

code/machine/console.cc

@@ -172,3 +172,19 @@ ConsoleOutput::PutChar(char ch)
     kernel->interrupt->Schedule(this, ConsoleTime, ConsoleWriteInt);
 }
 
+//----------------------------------------------------------------------
+// ConsoleOutput::PutInt()
+// 	Write a int to the simulated display, schedule an interrupt 
+//	to occur in the future, and return.
+//----------------------------------------------------------------------
+
+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 +76,9 @@ 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 value);
+
     void CallBack();		// Invoked when next character can be put
 				// out to the display.
 

code/machine/interrupt.cc

@@ -22,6 +22,7 @@
 
 #include "copyright.h"
 #include "interrupt.h"
+#include "synchconsole.h"
 #include "main.h"
 
 // String definitions for debugging messages
@@ -359,3 +360,31 @@ Interrupt::DumpState()
     cout << "\nEnd of pending interrupts\n";
 }
 
+void Interrupt::PrintInt(int value)
+{
+    kernel->synchConsoleOut->PutInt(value);
+}
+
+OpenFileId
+Interrupt::OpenFile(char *filename)
+{
+    return kernel->fileSystem->OpenFiles(filename);
+}
+
+int 
+Interrupt::WriteFile(char *buffer, int size, OpenFileId fd)
+{
+    return kernel->fileSystem->WriteFile(buffer, size, fd);
+}
+
+int 
+Interrupt::CloseFile(OpenFileId fd)
+{
+    return kernel->fileSystem->CloseFile(fd);
+}
+
+int 
+Interrupt::ReadFile(char *buffer, int size, OpenFileId fd)
+{
+    return kernel->fileSystem->ReadFile(buffer, size, fd);
+}

code/machine/interrupt.h

@@ -37,6 +37,10 @@
 #include "list.h"
 #include "callback.h"
 
+#include "filesys.h"
+
+typedef int OpenFileId;
+
 // Interrupts can be disabled (IntOff) or enabled (IntOn)
 enum IntStatus { IntOff, IntOn };
 
@@ -48,8 +52,10 @@ enum MachineStatus {IdleMode, SystemMode, UserMode};
 // IntType records which hardware device generated an interrupt.
 // In Nachos, we support a hardware timer device, a disk, a console
 // display and keyboard, and a network.
-enum IntType { TimerInt, DiskInt, ConsoleWriteInt, ConsoleReadInt, 
+enum IntType {
-			NetworkSendInt, NetworkRecvInt};
+  TimerInt, DiskInt, ConsoleWriteInt, ConsoleReadInt,
+  NetworkSendInt, NetworkRecvInt
+};
 
 // The following class defines an interrupt that is scheduled
 // to occur in the future.  The internal data structures are
@@ -96,6 +102,10 @@ class Interrupt {
 
   void PrintInt(int number);
   int CreateFile(char* filename);
+  OpenFileId OpenFile(char* filename);
+  int WriteFile(char* buffer, int size, OpenFileId fd);
+  int CloseFile(OpenFileId fd);
+  int ReadFile(char* buffer, int size, OpenFileId fd);
 
   void YieldOnReturn();	// cause a context switch on return 
   // from an interrupt handler

code/machine/machine.h

@@ -53,6 +53,8 @@ enum ExceptionType { NoException,           // Everything ok!
 		     OverflowException,     // Integer overflow in add or sub.
 		     IllegalInstrException, // Unimplemented or reserved instr.
 		    
+			 MemoryLimitException, // Insufficient memory
+
 		     NumExceptionTypes
 };
 

code/machine/stats.h

@@ -53,7 +53,10 @@ const int UserTick = 	   1;	// advance for each user-level instruction
 const int SystemTick = 10; 	// advance each time interrupts are enabled
 const int RotationTime = 500; 	// time disk takes to rotate one sector
 const int SeekTime = 500;  	// time disk takes to seek past one track
-const int ConsoleTime =	 100;	// time to read or write one character
+
+// MP4 MODIFIED
+const int ConsoleTime = 1;	// time to read or write one character
+
 const int NetworkTime = 100;  	// time to send or receive one packet
 const int TimerTicks = 100;  	// (average) time between timer interrupts
 

code/test/Makefile

@@ -107,13 +107,13 @@ 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 = mp4_consoleIO_1 mp4_consoleIO_2 mp4_consoleIO_3 mp4_consoleIO_4
-PROGRAMS = halt
 endif
 
 all: $(PROGRAMS)
@@ -121,72 +121,34 @@ all: $(PROGRAMS)
 start.o: start.S ../userprog/syscall.h
 	$(CC) $(CFLAGS) $(ASFLAGS) -c start.S
 
-halt.o: halt.c
+mp4_consoleIO_1.o: mp4_consoleIO_1.c
-	$(CC) $(CFLAGS) -c halt.c
+	$(CC) $(CFLAGS) -c mp4_consoleIO_1.c
-halt: halt.o start.o
-	$(LD) $(LDFLAGS) start.o halt.o -o halt.coff
-	$(COFF2NOFF) halt.coff halt
 
-add.o: add.c
+mp4_consoleIO_1: mp4_consoleIO_1.o start.o
-	$(CC) $(CFLAGS) -c add.c
+	$(LD) $(LDFLAGS) start.o mp4_consoleIO_1.o -o mp4_consoleIO_1.coff
+	$(COFF2NOFF) mp4_consoleIO_1.coff mp4_consoleIO_1
 
-add: add.o start.o
-	$(LD) $(LDFLAGS) start.o add.o -o add.coff
-	$(COFF2NOFF) add.coff add
 
-shell.o: shell.c
+mp4_consoleIO_2.o: mp4_consoleIO_2.c
-	$(CC) $(CFLAGS) -c shell.c
+	$(CC) $(CFLAGS) -c mp4_consoleIO_2.c
-shell: shell.o start.o
-	$(LD) $(LDFLAGS) start.o shell.o -o shell.coff
-	$(COFF2NOFF) shell.coff shell
 
-sort.o: sort.c
+mp4_consoleIO_2: mp4_consoleIO_2.o start.o
-	$(CC) $(CFLAGS) -c sort.c
+	$(LD) $(LDFLAGS) start.o mp4_consoleIO_2.o -o mp4_consoleIO_2.coff
-sort: sort.o start.o
+	$(COFF2NOFF) mp4_consoleIO_2.coff mp4_consoleIO_2
-	$(LD) $(LDFLAGS) start.o sort.o -o sort.coff
-	$(COFF2NOFF) sort.coff sort
 
-segments.o: segments.c
+mp4_consoleIO_3.o: mp4_consoleIO_3.c
-	$(CC) $(CFLAGS) -c segments.c
+	$(CC) $(CFLAGS) -c mp4_consoleIO_3.c
-segments: segments.o start.o
-	$(LD) $(LDFLAGS) start.o segments.o -o segments.coff
-	$(COFF2NOFF) segments.coff segments
 
-matmult.o: matmult.c
+mp4_consoleIO_3: mp4_consoleIO_3.o start.o
-	$(CC) $(CFLAGS) -c matmult.c
+	$(LD) $(LDFLAGS) start.o mp4_consoleIO_3.o -o mp4_consoleIO_3.coff
-matmult: matmult.o start.o
+	$(COFF2NOFF) mp4_consoleIO_3.coff mp4_consoleIO_3
-	$(LD) $(LDFLAGS) start.o matmult.o -o matmult.coff
-	$(COFF2NOFF) matmult.coff matmult
 
-consoleIO_test1.o: consoleIO_test1.c
+mp4_consoleIO_4.o: mp4_consoleIO_4.c
-	$(CC) $(CFLAGS) -c consoleIO_test1.c
+	$(CC) $(CFLAGS) -c mp4_consoleIO_4.c
-consoleIO_test1: consoleIO_test1.o start.o
-	$(LD) $(LDFLAGS) start.o consoleIO_test1.o -o consoleIO_test1.coff
-	$(COFF2NOFF) consoleIO_test1.coff consoleIO_test1
 
-consoleIO_test2.o: consoleIO_test2.c
+mp4_consoleIO_4: mp4_consoleIO_4.o start.o
-	$(CC) $(CFLAGS) -c consoleIO_test2.c
+	$(LD) $(LDFLAGS) start.o mp4_consoleIO_4.o -o mp4_consoleIO_4.coff
-consoleIO_test2: consoleIO_test2.o start.o
+	$(COFF2NOFF) mp4_consoleIO_4.coff mp4_consoleIO_4
-	$(LD) $(LDFLAGS) start.o consoleIO_test2.o -o consoleIO_test2.coff
-	$(COFF2NOFF) consoleIO_test2.coff consoleIO_test2
-	
-fileIO_test1.o: fileIO_test1.c
-	$(CC) $(CFLAGS) -c fileIO_test1.c
-fileIO_test1: fileIO_test1.o start.o
-	$(LD) $(LDFLAGS) start.o fileIO_test1.o -o fileIO_test1.coff
-	$(COFF2NOFF) fileIO_test1.coff fileIO_test1
-	
-fileIO_test2.o: fileIO_test2.c
-	$(CC) $(CFLAGS) -c fileIO_test2.c
-fileIO_test2: fileIO_test2.o start.o
-	$(LD) $(LDFLAGS) start.o fileIO_test2.o -o fileIO_test2.coff
-	$(COFF2NOFF) fileIO_test2.coff fileIO_test2
-
-fileIO_test3.o: fileIO_test3.c
-	$(CC) $(CFLAGS) -c fileIO_test3.c
-fileIO_test3: fileIO_test3.o start.o
-	$(LD) $(LDFLAGS) start.o fileIO_test3.o -o fileIO_test3.coff
-	$(COFF2NOFF) fileIO_test3.coff fileIO_test3
 	
 
 clean:
@@ -196,6 +158,13 @@ clean:
 distclean: clean
 	$(RM) -f $(PROGRAMS)
 
+run: $(PROGRAMS)
+	timeout 1 $(NACHOS) -ep mp4_consoleIO_1 70 -ep mp4_consoleIO_3 80 -ep mp4_consoleIO_2 50
+	echo 'done'
+
+debug: $(PROGRAMS)
+	timeout 1 $(NACHOS) -d z -ep mp4_consoleIO_1 60 -ep mp4_consoleIO_2 70
+
 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
+int main() {
-main()
-{
   int n;
-	for (n=9;n>5;n--) {
+  for (n = 9; n > 5; n--)
     PrintInt(n);
-	}
+  return 0;
-        Halt();
 }
 

code/test/consoleIO_test2.c

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

code/test/file1.test

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

code/test/mp4_consoleIO_1.c

@@ -0,0 +1,10 @@
+#include "syscall.h"
+
+int main()
+{
+	int n;
+	for (n = 0; n < 4; n++) {
+		PrintInt(1);
+	}
+	return 0;
+}

code/test/mp4_consoleIO_2.c

@@ -0,0 +1,9 @@
+#include "syscall.h"
+int main()
+{
+	int n;
+	for (n = 0; n < 5; n++) {
+		PrintInt(2);
+	}
+	return 0;
+}

code/test/mp4_consoleIO_3.c

@@ -0,0 +1,10 @@
+#include "syscall.h"
+int
+main()
+{
+	int n;
+	for (n = 0; n < 12; n++) {
+		PrintInt(3);
+	}
+	return 0;
+}

code/test/mp4_consoleIO_4.c

@@ -0,0 +1,9 @@
+#include "syscall.h"
+int main()
+{
+    int n;
+    for (n = 0; n < 11; n++) {
+        PrintInt(4);
+    }
+    return 0;
+}

code/test/os_students.sh

@@ -1,3 +1,9 @@
-make clean
+make distclean
 make 
-../build.linux/nachos -e halt
+rm -f *.o *.ii
+rm -f *.coff
+echo "=========================="
+timeout 1 ../build.linux/nachos -e mp4_consoleIO_1 -e mp4_consoleIO_2 
+echo "=========================="
+timeout 1 ../build.linux/nachos -e mp4_consoleIO_3 -e mp4_consoleIO_4
+echo "done"

code/test/start.S

@@ -58,6 +58,14 @@ MSG:
 	j	$31
 	.end MSG
 
+	.globl PrintInt
+	.ent   PrintInt
+PrintInt:
+	addiu $2,$0,SC_PrintInt
+	syscall
+	j	$31
+	.end PrintInt
+
 	.globl Add
 	.ent	Add
 Add:

code/test/test.c

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

code/threads/alarm.cc

@@ -49,7 +49,9 @@ Alarm::CallBack()
     Interrupt* interrupt = kernel->interrupt;
     MachineStatus status = interrupt->getStatus();
 
+    // Todo ----
     if (status != IdleMode) {
-	interrupt->YieldOnReturn();
+        // interrupt->YieldOnReturn();
     }
+    // ---------
 }

code/threads/kernel.cc

@@ -43,32 +43,48 @@ Kernel::Kernel(int argc, char **argv)
                                     // number generator
       randomSlice = TRUE;
       i++;
-        } else if (strcmp(argv[i], "-s") == 0) {
+    }
+    else if (strcmp(argv[i], "-s") == 0) {
       debugUserProg = TRUE;
-		} else if (strcmp(argv[i], "-e") == 0) {
+    }
+    // Todo ----
+    else if (strcmp(argv[i], "-e") == 0) {
       execfile[++execfileNum] = argv[++i];
       cout << execfile[execfileNum] << "\n";
-		} else if (strcmp(argv[i], "-ci") == 0) {
+    }
+    else if (strcmp(argv[i], "-ep") == 0) {
+      execfile[++execfileNum] = argv[++i];
+      execPriority[execfileNum] = atoi(argv[++i]);
+      cout << execfile[execfileNum] << " with priority "
+        << execPriority[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) {
+    }
+    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) {
+    }
+    else if (strcmp(argv[i], "-f") == 0) {
       formatFlag = TRUE;
 #endif
-        } else if (strcmp(argv[i], "-n") == 0) {
+    }
+    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) {
+    }
+    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) {
+    }
+    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";
@@ -111,9 +127,12 @@ Kernel::Initialize()
 #else
     fileSystem = new FileSystem(formatFlag);
 #endif // FILESYS_STUB
-    postOfficeIn = new PostOfficeInput(10);
-    postOfficeOut = new PostOfficeOutput(reliability);
 
+    // MP4 MODIFIED
+    // postOfficeIn = new PostOfficeInput(10);
+    // postOfficeOut = new PostOfficeOutput(reliability);
+
+    frameTable = new FrameTable();
     interrupt->Enable();
 }
 
@@ -133,8 +152,12 @@ Kernel::~Kernel()
     delete synchConsoleOut;
     delete synchDisk;
     delete fileSystem;
-    delete postOfficeIn;
+
-    delete postOfficeOut;
+    // MP4 MODIFIED
+    // delete postOfficeIn;
+    // delete postOfficeOut;
+
+    delete frameTable;
 
     Exit(0);
 }
@@ -261,16 +284,18 @@ void ForkExecute(Thread *t)
 void Kernel::ExecAll()
 {
     for (int i = 1;i <= execfileNum;i++) {
-		int a = Exec(execfile[i]);
+        int a = Exec(execfile[i], execPriority[i]);
     }
     currentThread->Finish();
     //Kernel::Exec();	
 }
 
-
+// Todo ----
-int Kernel::Exec(char* name)
+int Kernel::Exec(char* name, int priority)
 {
     t[threadNum] = new Thread(name, threadNum);
+    t[threadNum]->setPriority(priority);
+// ---------
     t[threadNum]->space = new AddrSpace();
     t[threadNum]->Fork((VoidFunctionPtr)&ForkExecute, (void*)t[threadNum]);
     threadNum++;

code/threads/kernel.h

@@ -25,7 +25,8 @@ class SynchConsoleInput;
 class SynchConsoleOutput;
 class SynchDisk;
 
-
+// Todo ----
+// ---------
 
 class Kernel {
   public:
@@ -37,7 +38,11 @@ class Kernel {
                           // from constructor because 
                           // refers to "kernel" as a global
     void ExecAll();
-	int Exec(char* name);
+
+    // Todo ----
+    int Exec(char* name, int priority);
+    // ---------
+
     void ThreadSelfTest();	// self test of threads and synchronization
 
     void ConsoleTest();         // interactive console self test
@@ -61,13 +66,18 @@ class Kernel {
     FileSystem *fileSystem;     
     PostOfficeInput *postOfficeIn;
     PostOfficeOutput *postOfficeOut;
-
+    FrameTable *frameTable;
     int hostName;               // machine identifier
 
   private:
 
     Thread* t[10];
+
+    // Todo ----
     char*   execfile[10];
+    int execPriority[10];
+    // ---------
+
     int execfileNum;
     int threadNum;
     bool randomSlice;		// enable pseudo-random time slicing
@@ -82,5 +92,3 @@ class Kernel {
 
 
 #endif // KERNEL_H
-
-

code/threads/scheduler.cc

@@ -22,6 +22,7 @@
 #include "debug.h"
 #include "scheduler.h"
 #include "main.h"
+#include <functional>
 
 //----------------------------------------------------------------------
 // Scheduler::Scheduler
@@ -29,9 +30,20 @@
 //	Initially, no ready threads.
 //----------------------------------------------------------------------
 
+// Todo ----
+
+int cmp(Thread *a, Thread *b)
+{
+  int ap = a->getPriority();
+  int bp = b->getPriority();
+  return (ap < bp) - (ap > bp);
+}
+
 Scheduler::Scheduler()
 {
-    readyList = new List<Thread *>; 
+  readyList = new SortedList(cmp);
+// ---------
+
   toBeDestroyed = NULL;
 }
 
@@ -60,7 +72,9 @@ Scheduler::ReadyToRun (Thread *thread)
   DEBUG(dbgThread, "Putting thread on ready list: " << thread->getName());
   //cout << "Putting thread on ready list: " << thread->getName() << endl ;
   thread->setStatus(READY);
-    readyList->Append(thread);
+
+  DEBUG(dbgSche, "[A] Tick [" << kernel->stats->totalTicks << "]: Process [" << thread->getName() << "] is inserted into queue.");
+  readyList->Insert(thread);
 }
 
 //----------------------------------------------------------------------
@@ -78,7 +92,9 @@ Scheduler::FindNextToRun ()
 
   if (readyList->IsEmpty()) {
     return NULL;
-    } else {
+  }
+  else {
+    DEBUG(dbgSche, "[B] Tick [" << kernel->stats->totalTicks << "]: Process [" << readyList->Front()->getName() << "] is removed from queue.");
     return readyList->RemoveFront();
   }
 }
@@ -124,6 +140,7 @@ Scheduler::Run (Thread *nextThread, bool finishing)
   nextThread->setStatus(RUNNING);      // nextThread is now running
 
   DEBUG(dbgThread, "Switching from: " << oldThread->getName() << " to: " << nextThread->getName());
+  DEBUG(dbgSche, "[C] Tick [" << kernel->stats->totalTicks << "]: Process [" << nextThread->getName() << "] is now selected for execution, thread [" << oldThread->getName() << "] is replaced.");
 
   // This is a machine-dependent assembly language routine defined 
   // in switch.s.  You may have to think

code/threads/scheduler.h

@@ -35,8 +35,11 @@ class Scheduler {
     // SelfTest for scheduler is implemented in class Thread
     
   private:
-    List<Thread *> *readyList;  // queue of threads that are ready to run,
+    // Todo ----
+    SortedList<Thread *> *readyList;  // queue of threads that are ready to run,
                                       // but not running
+    // ---------
+
     Thread *toBeDestroyed;	// finishing thread to be destroyed
                             // by the next thread that runs
 };

code/threads/thread.cc

@@ -40,7 +40,8 @@ Thread::Thread(char* threadName, int threadID)
     stackTop = NULL;
     stack = NULL;
     status = JUST_CREATED;
-    for (int i = 0; i < MachineStateSize; i++) {
+    for (int i = 0; i < MachineStateSize; i++)
+    {
         machineState[i] = NULL; // not strictly necessary, since
                                 // new thread ignores contents
                                 // of machine registers
@@ -88,8 +89,7 @@ Thread::~Thread()
 //	"arg" is a single argument to be passed to the procedure.
 //----------------------------------------------------------------------
 
-void 
+void Thread::Fork(VoidFunctionPtr func, void *arg)
-Thread::Fork(VoidFunctionPtr func, void *arg)
 {
     Interrupt *interrupt = kernel->interrupt;
     Scheduler *scheduler = kernel->scheduler;
@@ -119,10 +119,10 @@ Thread::Fork(VoidFunctionPtr func, void *arg)
 // 	Don't do this: void foo() { int bigArray[10000]; ... }
 //----------------------------------------------------------------------
 
-void
+void Thread::CheckOverflow()
-Thread::CheckOverflow()
+{
+    if (stack != NULL)
     {
-    if (stack != NULL) {
 #ifdef HPUX // Stacks grow upward on the Snakes
         ASSERT(stack[StackSize - 1] == STACK_FENCEPOST);
 #else
@@ -142,8 +142,7 @@ Thread::CheckOverflow()
 //	2. enable interrupts (so we can get time-sliced)
 //----------------------------------------------------------------------
 
-void
+void Thread::Begin()
-Thread::Begin ()
 {
     ASSERT(this == kernel->currentThread);
     DEBUG(dbgThread, "Beginning thread: " << name);
@@ -167,8 +166,7 @@ Thread::Begin ()
 //----------------------------------------------------------------------
 
 //
-void
+void Thread::Finish()
-Thread::Finish ()
 {
     (void)kernel->interrupt->SetLevel(IntOff);
     ASSERT(this == kernel->currentThread);
@@ -178,7 +176,6 @@ Thread::Finish ()
     // not reached
 }
 
-
 //----------------------------------------------------------------------
 // Thread::Yield
 // 	Relinquish the CPU if any other thread is ready to run.
@@ -197,8 +194,7 @@ Thread::Finish ()
 // 	Similar to Thread::Sleep(), but a little different.
 //----------------------------------------------------------------------
 
-void
+void Thread::Yield()
-Thread::Yield ()
 {
     Thread *nextThread;
     IntStatus oldLevel = kernel->interrupt->SetLevel(IntOff);
@@ -208,7 +204,8 @@ Thread::Yield ()
     DEBUG(dbgThread, "Yielding thread: " << name);
 
     nextThread = kernel->scheduler->FindNextToRun();
-    if (nextThread != NULL) {
+    if (nextThread != NULL)
+    {
         kernel->scheduler->ReadyToRun(this);
         kernel->scheduler->Run(nextThread, FALSE);
     }
@@ -235,8 +232,7 @@ Thread::Yield ()
 //	so that there can't be a time slice between pulling the first thread
 //	off the ready list, and switching to it.
 //----------------------------------------------------------------------
-void
+void Thread::Sleep(bool finishing)
-Thread::Sleep (bool finishing)
 {
     Thread *nextThread;
 
@@ -247,7 +243,8 @@ Thread::Sleep (bool finishing)
 
     status = BLOCKED;
     // cout << "debug Thread::Sleep " << name << "wait for Idle\n";
-    while ((nextThread = kernel->scheduler->FindNextToRun()) == NULL) {
+    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
@@ -279,11 +276,14 @@ PLabelToAddr(void *plabel)
 {
     int funcPtr = (int)plabel;
 
-    if (funcPtr & 0x02) {
+    if (funcPtr & 0x02)
+    {
         // L-Field is set.  This is a PLT pointer
         funcPtr -= 2; // Get rid of the L bit
         return (*(void **)funcPtr);
-    } else {
+    }
+    else
+    {
         // L-field not set.
         return plabel;
     }
@@ -302,8 +302,7 @@ PLabelToAddr(void *plabel)
 //	"arg" is the parameter to be passed to the procedure
 //----------------------------------------------------------------------
 
-void
+void Thread::StackAllocate(VoidFunctionPtr func, void *arg)
-Thread::StackAllocate (VoidFunctionPtr func, void *arg)
 {
     stack = (int *)AllocBoundedArray(StackSize * sizeof(int));
 
@@ -336,7 +335,6 @@ Thread::StackAllocate (VoidFunctionPtr func, void *arg)
     *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
@@ -372,8 +370,7 @@ Thread::StackAllocate (VoidFunctionPtr func, void *arg)
 //	while executing kernel code.  This routine saves the former.
 //----------------------------------------------------------------------
 
-void
+void Thread::SaveUserState()
-Thread::SaveUserState()
 {
     for (int i = 0; i < NumTotalRegs; i++)
         userRegisters[i] = kernel->machine->ReadRegister(i);
@@ -388,14 +385,12 @@ Thread::SaveUserState()
 //	while executing kernel code.  This routine restores the former.
 //----------------------------------------------------------------------
 
-void
+void Thread::RestoreUserState()
-Thread::RestoreUserState()
 {
     for (int i = 0; i < NumTotalRegs; i++)
         kernel->machine->WriteRegister(i, userRegisters[i]);
 }
 
-
 //----------------------------------------------------------------------
 // SimpleThread
 // 	Loop 5 times, yielding the CPU to another ready thread
@@ -410,7 +405,8 @@ SimpleThread(int which)
 {
     int num;
 
-    for (num = 0; num < 5; num++) {
+    for (num = 0; num < 5; num++)
+    {
         cout << "*** thread " << which << " looped " << num << " times\n";
         kernel->currentThread->Yield();
     }
@@ -422,8 +418,7 @@ SimpleThread(int which)
 //	to call SimpleThread, and then calling SimpleThread ourselves.
 //----------------------------------------------------------------------
 
-void
+void Thread::SelfTest()
-Thread::SelfTest()
 {
     DEBUG(dbgThread, "Entering Thread::SelfTest");
 
@@ -433,3 +428,16 @@ Thread::SelfTest()
     kernel->currentThread->Yield();
     SimpleThread(0);
 }
+
+// Todo ----
+int Thread::getPriority() const
+{
+  return priority;
+}
+
+void Thread::setPriority(int p)
+{
+  ASSERT(p >= 0 && p <= 149);
+  priority = p;
+}
+// ---------

code/threads/thread.h

@@ -80,6 +80,10 @@ class Thread {
     int *stackTop;			 // the current stack pointer
     void *machineState[MachineStateSize];  // all registers except for stackTop
 
+    // Todo ----
+    int priority;
+    // ---------
+
   public:
     Thread(char* debugName, int threadID);		// initialize a Thread 
     ~Thread(); 				// deallocate a Thread
@@ -89,6 +93,11 @@ class Thread {
 
     // basic thread operations
 
+    // Todo ----
+    int getPriority() const;
+    void setPriority(int p);
+    // ---------
+
     void Fork(VoidFunctionPtr func, void *arg); 
     				// Make thread run (*func)(arg)
     void Yield();  		// Relinquish the CPU if any 

code/userprog/addrspace.cc

@@ -27,7 +27,6 @@
 //	object file header, in case the file was generated on a little
 //	endian machine, and we're now running on a big endian machine.
 //----------------------------------------------------------------------
-
 static void
 SwapHeader(NoffHeader* noffH)
 {
@@ -64,9 +63,10 @@ SwapHeader (NoffHeader *noffH)
 //	memory.  For now, this is really simple (1:1), since we are
 //	only uniprogramming, and we have a single unsegmented page table
 //----------------------------------------------------------------------
-
 AddrSpace::AddrSpace()
 {
+    pageTable = NULL; // initialize with NULL
+    /*
         pageTable = new TranslationEntry[NumPhysPages];
         for (int i = 0; i < NumPhysPages; i++) {
         pageTable[i].virtualPage = i;	// for now, virt page # = phys page #
@@ -79,6 +79,7 @@ AddrSpace::AddrSpace()
 
         // zero out the entire address space
         bzero(kernel->machine->mainMemory, MemorySize);
+     */
 }
 
 //----------------------------------------------------------------------
@@ -88,7 +89,9 @@ AddrSpace::AddrSpace()
 
 AddrSpace::~AddrSpace()
 {
-   delete pageTable;
+    /* delete pageTable; */
+    // release frame table by page table
+    kernel->frameTable->Release(pageTable, numPages);
 }
 
 
@@ -101,7 +104,6 @@ AddrSpace::~AddrSpace()
 //
 //	"fileName" is the file containing the object code to load into memory
 //----------------------------------------------------------------------
-
 bool
 AddrSpace::Load(char* fileName)
 {
@@ -135,37 +137,102 @@ AddrSpace::Load(char *fileName)
     numPages = divRoundUp(size, PageSize);
     size = numPages * PageSize;
 
-    ASSERT(numPages <= NumPhysPages);		// check we're not trying
+    pageTable = kernel->frameTable->Allocate(numPages);
-						// to run anything too big --
+    if (!pageTable) {
-						// at least until we have
+        kernel->interrupt->setStatus(SystemMode);
-						// virtual memory
+        ExceptionHandler(MemoryLimitException);
+        kernel->interrupt->setStatus(UserMode);
+    }
 
     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
+    uint paddr; // physical address
+    ExceptionType ex; // occurring exception
+    int sz, // total size to load
+        vaddr, // base virtual address
+        fpos, // base file position
+        to_load; // size to load on each time
+
     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]), 
+        sz = noffH.code.size;
-			noffH.code.size, noffH.code.inFileAddr);
+        vaddr = noffH.code.virtualAddr;
+        fpos = noffH.code.inFileAddr;
+
+        for (uint offset = 0; offset < sz; offset += PageSize) {
+            ex = Translate(vaddr + offset, &paddr, 1);
+
+            if (ex != NoException) {
+                kernel->interrupt->setStatus(SystemMode);
+                ExceptionHandler(ex);
+                kernel->interrupt->setStatus(UserMode);
             }
+
+            to_load = offset + PageSize < sz ? PageSize : sz - offset;
+
+            executable->ReadAt(
+                &(kernel->machine->mainMemory[paddr]),
+                to_load, fpos + offset);
+        }
+    }
+
     if (noffH.initData.size > 0) {
         DEBUG(dbgAddr, "Initializing data segment.");
         DEBUG(dbgAddr, noffH.initData.virtualAddr << ", " << noffH.initData.size);
+
+        sz = noffH.initData.size;
+        vaddr = noffH.initData.virtualAddr;
+        fpos = noffH.initData.inFileAddr;
+
+        for (uint offset = 0; offset < sz; offset += PageSize) {
+            ex = Translate(vaddr + offset, &paddr, 1);
+
+            if (ex != NoException) {
+                kernel->interrupt->setStatus(SystemMode);
+                ExceptionHandler(ex);
+                kernel->interrupt->setStatus(UserMode);
+            }
+
+            to_load = offset + PageSize < sz ? PageSize : sz - offset;
+
             executable->ReadAt(
-		&(kernel->machine->mainMemory[noffH.initData.virtualAddr]),
+                &(kernel->machine->mainMemory[paddr]),
-			noffH.initData.size, noffH.initData.inFileAddr);
+                to_load, fpos + offset);
+        }
     }
 
 #ifdef RDATA
     if (noffH.readonlyData.size > 0) {
         DEBUG(dbgAddr, "Initializing read only data segment.");
         DEBUG(dbgAddr, noffH.readonlyData.virtualAddr << ", " << noffH.readonlyData.size);
+
+        sz = noffH.readonlyData.size;
+        vaddr = noffH.readonlyData.virtualAddr;
+        fpos = noffH.readonlyData.inFileAddr;
+
+        // read only flag for page table
+        for (int i = 0, lim = divRoundUp(sz, PageSize),
+            from = vaddr / PageSize; i < lim; ++i)
+            pageTable[from + i].readOnly = TRUE;
+
+        for (uint offset = 0; offset < sz; offset += PageSize) {
+            ex = Translate(vaddr + offset, &paddr, 0); // read only
+
+            if (ex != NoException) {
+                kernel->interrupt->setStatus(SystemMode);
+                ExceptionHandler(ex);
+                kernel->interrupt->setStatus(UserMode);
+            }
+
+            to_load = offset + PageSize < sz ? PageSize : sz - offset;
+
             executable->ReadAt(
-		&(kernel->machine->mainMemory[noffH.readonlyData.virtualAddr]),
+                &(kernel->machine->mainMemory[paddr]),
-			noffH.readonlyData.size, noffH.readonlyData.inFileAddr);
+                to_load, fpos + offset);
+        }
     }
 #endif
 
@@ -181,7 +248,6 @@ AddrSpace::Load(char *fileName)
 //      the address space
 //
 //----------------------------------------------------------------------
-
 void
 AddrSpace::Execute(char* fileName)
 {
@@ -191,7 +257,7 @@ AddrSpace::Execute(char* fileName)
     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 program
 
     ASSERTNOTREACHED();			// machine->Run never returns;
     // the address space exits
@@ -208,7 +274,6 @@ AddrSpace::Execute(char* fileName)
 //	will be saved/restored into the currentThread->userRegisters
 //	when this thread is context switched out.
 //----------------------------------------------------------------------
-
 void
 AddrSpace::InitRegisters()
 {
@@ -242,9 +307,9 @@ AddrSpace::InitRegisters()
 //
 //	For now, don't need to save anything!
 //----------------------------------------------------------------------
-
 void AddrSpace::SaveState()
-{}
+{
+}
 
 //----------------------------------------------------------------------
 // AddrSpace::RestoreState
@@ -253,7 +318,6 @@ void AddrSpace::SaveState()
 //
 //      For now, tell the machine where to find the page table.
 //----------------------------------------------------------------------
-
 void AddrSpace::RestoreState()
 {
     kernel->machine->pageTable = pageTable;
@@ -311,6 +375,43 @@ AddrSpace::Translate(unsigned int vaddr, unsigned int *paddr, int isReadWrite)
     return NoException;
 }
 
-
+FrameTable::FrameTable() {
+    for (int i = 0; i < NumPhysPages; ++i)
+        available.Append(i);
+}
+
+FrameTable::~FrameTable() {}
+
+uint FrameTable::RemainSize() { return available.NumInList(); }
+
+PageTable FrameTable::Allocate(uint pageNum) {
+    // if not enough memory
+    if (RemainSize() < pageNum)
+        return NULL;
+
+    PageTable ptb = new TranslationEntry[pageNum];
+
+    for (int i = 0; i < pageNum; ++i) {
+        ptb[i].virtualPage = i;
+        int f = available.RemoveFront(); // frame number
+        ptb[i].physicalPage = f;
+        // initialize flags
+        ptb[i].valid = TRUE;
+        ptb[i].use = FALSE;
+        ptb[i].dirty = FALSE;
+        ptb[i].readOnly = FALSE;
+        // zero out the entire address space
+        bzero(kernel->machine->mainMemory + f * PageSize, PageSize);
+    }
+    return ptb;
+}
+
+void FrameTable::Release(PageTable ptb, int pageNum) {
+    if (!ptb)
+        return; // nothing to release
+    for (int i = 0; i < pageNum; ++i)
+        available.Append(ptb[i].physicalPage);
+    delete[] ptb;
+}
 
 

code/userprog/addrspace.h

@@ -51,3 +51,51 @@ class AddrSpace {
 };
 
 #endif // ADDRSPACE_H
+
+#ifndef FRAME_TABLE_H
+#define FRAME_TABLE_H
+
+#include "machine.h"
+#include "list.h"
+
+/**
+ * Data structure of Virtual Memory
+ */
+typedef TranslationEntry* PageTable;
+
+/**
+ * Data structure of Physical Memory
+ */
+class FrameTable {
+public:
+  /**
+   * Initialize a frame table
+   */
+  FrameTable();
+  ~FrameTable();
+
+  /**
+   * Allocate pageNum of frames (pages) and collect
+   * corresponding translation information into a page table.
+   *
+   * @param pageNum numbers of pages
+   * @return a new Page table, NULL if not enough memory space
+   */
+  PageTable Allocate(uint pageNum);
+
+  /**
+   * Release the physical memory frame
+   * which the info stored in PageTable
+   */
+  void Release(PageTable ptb, int pageNum);
+
+  /**
+   * @return the remaining numbers of entry of the frame table
+   */
+  uint RemainSize();
+
+private:
+  List<int> available;
+};
+
+#endif /* FRAME_TABLE_H */

code/userprog/exception.cc

@@ -54,6 +54,7 @@ ExceptionHandler(ExceptionType which)
 	int type = kernel->machine->ReadRegister(2);
 	int val;
 	int status, exit, threadID, programID;
+	int fd, size;
 	DEBUG(dbgSys, "Received Exception " << which << " type: " << type << "\n");
 	switch (which) {
 	case SyscallException:
@@ -74,6 +75,13 @@ ExceptionHandler(ExceptionType which)
 			SysHalt();
 			ASSERTNOTREACHED();
 			break;
+		case SC_PrintInt:
+			val = 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;
 		case SC_Create:
 			val = kernel->machine->ReadRegister(4);
 			{
@@ -88,6 +96,62 @@ ExceptionHandler(ExceptionType which)
 			return;
 			ASSERTNOTREACHED();
 			break;
+		case SC_Open:
+			val = kernel->machine->ReadRegister(4);
+			{
+				char* filename = &(kernel->machine->mainMemory[val]);
+				//cout << filename << endl;
+				fd = SysOpen(filename);
+				kernel->machine->WriteRegister(2, (int)fd);
+			}
+			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:
+			val = kernel->machine->ReadRegister(4);
+			size = kernel->machine->ReadRegister(5);
+			fd = kernel->machine->ReadRegister(6);
+			{
+				char* buffer = &(kernel->machine->mainMemory[val]);
+				size = SysWrite(buffer, size, fd);
+				kernel->machine->WriteRegister(2, (int)size);
+			}
+			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:
+			fd = kernel->machine->ReadRegister(4);
+			{
+				val = SysClose(fd);
+				kernel->machine->WriteRegister(2, (int)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_Read:
+			val = kernel->machine->ReadRegister(4);
+			size = kernel->machine->ReadRegister(5);
+			fd = kernel->machine->ReadRegister(6);
+			{
+				char* buffer = &(kernel->machine->mainMemory[val]);
+				size = SysRead(buffer, size, fd);
+				kernel->machine->WriteRegister(2, (int)size);
+			}
+			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*/

code/userprog/hw4_consoleIO_1.c

@@ -0,0 +1,11 @@
+#include "syscall.h"
+
+int
+main()
+{
+  int n;
+  for (n = 0; n < 4; n++) {
+    PrintInt(1);
+  }
+  return 0;
+}

code/userprog/hw4_consoleIO_2.c

@@ -0,0 +1,11 @@
+#include "syscall.h"
+
+int
+main()
+{
+  int n;
+  for (n = 0; n < 5; n++) {
+    PrintInt(2);
+  }
+  return 0;
+}

code/userprog/hw4_consoleIO_3.c

@@ -0,0 +1,12 @@
+#include "syscall.h"
+
+int
+main()
+{
+  int n;
+
+  for (n = 0; n < 12; n++) {
+    PrintInt(3);
+  }
+  return 0;
+}

code/userprog/hw4_consoleIO_4.c

@@ -0,0 +1,12 @@
+#include "syscall.h"
+
+int
+main()
+{
+  int n;
+
+  for (n = 0; n < 11; n++) {
+    PrintInt(4);
+  }
+  return 0;
+}

code/userprog/ksyscall.h

@@ -15,6 +15,7 @@
 
 #include "synchconsole.h"
 
+typedef int OpenFileId;
 
 void SysHalt()
 {
@@ -34,5 +35,37 @@ int SysCreate(char *filename)
 	return kernel->interrupt->CreateFile(filename);
 }
 
+void SysPrintInt(int value)
+{
+	kernel->interrupt->PrintInt(value);
+}
+
+// -1: open fail
+// fd
+OpenFileId SysOpen(char* filename)
+{
+	return kernel->interrupt->OpenFile(filename);
+}
+
+// -1: write fail
+// size 
+int SysWrite(char* buffer, int size, OpenFileId fd)
+{
+	return kernel->interrupt->WriteFile(buffer, size, fd);
+}
+
+// 1: close success
+// 0: close fail
+int SysClose(OpenFileId fd)
+{
+	return kernel->interrupt->CloseFile(fd);
+}
+
+// -1: read fail
+// size
+int SysRead(char* buffer, int size, OpenFileId fd)
+{
+	return kernel->interrupt->ReadFile(buffer, size, fd);
+}
 
 #endif /* ! __USERPROG_KSYSCALL_H__ */

code/userprog/noff.h

@@ -6,8 +6,7 @@
  */
 
 #define NOFFMAGIC	0xbadfad 	/* magic number denoting Nachos 
-					 * object code file 
+                              /* object code file*/
-					 */
 
 typedef struct segment {
    int virtualAddr;		/* location of segment in virt addr space */

code/userprog/synchconsole.cc

@@ -106,6 +106,20 @@ SynchConsoleOutput::PutChar(char ch)
     lock->Release();
 }
 
+//----------------------------------------------------------------------
+// SynchConsoleOutput::PutInt
+//      Write a int to the console display, waiting if necessary.
+//----------------------------------------------------------------------
+
+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

@@ -36,6 +36,7 @@
 #define SC_ThreadJoin   15
 #define SC_Add		42
 #define SC_MSG		100
+#define SC_PrintInt 16
 
 #ifndef IN_ASM
 
@@ -52,6 +53,11 @@
    /* Stop Nachos, and print out performance stats */
 void Halt();
 
+/*
+ * Show the int value on console
+ */
+void PrintInt(int value);
+
 /*
  * Add the two operants and return the result
  */

docker-compose.yaml

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