added System Call HALT function

src/userprog/syscall.c

@@ -51,6 +51,15 @@ syscall_handler (struct intr_frame *f)
   memread_user(f->esp, &syscall_number, sizeof(syscall_number));
 
   switch (syscall_number) {
+
+    case SYS_HALT:{
+      //Alsaloumi
+      // pintos -p ../examples/halt -a halt -- -q
+      // pintos -q run 'halt'
+      
+      shutdown_power_off();
+      break;
+      }
     case SYS_TELL: 
       {
         int fd;