README.md

 This is a variant of the Pintos Operating System for use as part of Operating Systems module at the University of the West of England (UWE).
+#this is the first edit By Mohamed2.Almarri@live.uwe.ac.uk
+

src/userprog/syscall.c

@@ -11,11 +11,57 @@ syscall_init (void)
 {
   intr_register_int (0x30, 3, INTR_ON, syscall_handler, "syscall");
 }
+/* from lib/syscall-nr.h 
+system calls numbers are 
+    SYS_HALT,                  0
+    SYS_EXIT,                  1
+    SYS_EXEC,                  2 
+    SYS_WAIT,                  3 
+    SYS_CREATE,                4
+    SYS_REMOVE,                5
+    SYS_OPEN,                  6
+    SYS_FILESIZE,              7
+    SYS_READ,                  8
+    SYS_WRITE,                 9
+    SYS_SEEK,                  10
+    SYS_TELL,                  11
+    SYS_CLOSE,                 12
 
+these are used for the case instead of number
+*/
 
 static void
 syscall_handler (struct intr_frame *f UNUSED)
 {
   printf ("system call!\n");
+  int syscall_nr=-1;
+  switch(syscall_nr) {
+	  case SYS_HALT:{
+		  printf ("system call, halt\n");
+      shutdown_power_off();
+		  break;
+    }
+    /*
+    // each team member should select on syscall.
+    // develop one from the cw document
+
+
+    case SYS_EXIT:{
+      //to be developed
+      break;
+    }
+    case SYS_EXEC:{
+      //to be developed
+      break;
+    }
+    case SYS_WAIT:{
+      //to be developed
+      break;
+    }
+    case SYS_WAIT:{
+      //to be developed
+      break;
+    }
+    */
   thread_exit ();
 }