Rewrite GetInt syscall

code/userprog/consoledriver.cc

@@ -70,13 +70,11 @@ void ConsoleDriver::PutInt(int n)
   delete [] buffer;
 }
 
-int ConsoleDriver::GetInt()
+void ConsoleDriver::GetInt(int * n)
 {
-  int n;
   char *buffer = new char[MAX_STRING_SIZE];
   GetString(buffer,MAX_STRING_SIZE);
-  sscanf(buffer, "%d", &n);
+  sscanf(buffer, "%d", n);
   delete [] buffer;
-  return n;
 }
 #endif // CHANGED

code/userprog/consoledriver.h

@@ -19,7 +19,7 @@ class ConsoleDriver:dontcopythis {
 	void PutString(const char *s); // Behaves like fputs(3S)
 	void GetString(char *s, int n); // Behaves like fgets(3S)
     void PutInt(int n);
-    int GetInt();
+    void GetInt(int * n);
   private:
 	Console *console;
 };

code/userprog/exception.cc

@@ -190,9 +190,11 @@ ExceptionHandler (ExceptionType which)
         case SC_GetInt:
           {
              DEBUG('s', "GetInt\n");
-             int n = consoledriver->GetInt();
+             int n;
+             int addr = machine->ReadRegister(4);
+             consoledriver->GetInt(&n);
              DEBUG('s', "Number entered: %d\n", n);
-             machine->WriteRegister(2,n);
+             machine->WriteMem(addr,sizeof(n),n);
              break;
           }
         #endif

code/userprog/syscall.h

@@ -143,7 +143,7 @@ void PutString (char *s);
 char GetChar();
 void GetString(char *s, int n );
 void PutInt(int n);  
-int GetInt();
+void GetInt( int * n);
 
 #endif // CHANGED