/* Creates a new kernel thread named NAME with the given initial
PRIORITY, which executes FUNCTION passing AUX as the argument,
- and adds it to the ready queue. If thread_start() has been
- called, then the new thread may be scheduled before
- thread_create() returns. It could even exit before
- thread_create() returns. Use a semaphore or some other form
- of synchronization if you need to ensure ordering. Returns
- the thread identifier for the new thread, or TID_ERROR if
- creation fails.
+ and adds it to the ready queue. Returns the thread identifier
+ for the new thread, or TID_ERROR if creation fails.
+
+ If thread_start() has been called, then the new thread may be
+ scheduled before thread_create() returns. It could even exit
+ before thread_create() returns. Contrariwise, the original
+ thread may run for any amount of time before the new thread is
+ scheduled. Use a semaphore or some other form of
+ synchronization if you need to ensure ordering.
The code provided sets the new thread's `priority' member to
PRIORITY, but no actual priority scheduling is implemented.
schedule ();
intr_set_level (old_level);
}
+
+/* Sets the current thread's priority to NEW_PRIORITY. */
+void
+thread_set_priority (int new_priority)
+{
+ thread_current ()->priority = new_priority;
+}
+
+/* Returns the current thread's priority. */
+int
+thread_get_priority (void)
+{
+ return thread_current ()->priority;
+}
\f
/* Idle thread. Executes when no other thread is ready to run. */
static void
thread_block ();
intr_enable ();
- /* Use CPU `hlt' instruction to wait for interrupt. */
+ /* Use CPU `hlt' instruction to wait for interrupt.
+ See [IA32-v2a] "HLT" and [IA32-v3] 7.7. */
asm ("hlt");
}
}
down to the start of a page. Because `struct thread' is
always at the beginning of a page and the stack pointer is
somewhere in the middle, this locates the curent thread. */
- asm ("movl %%esp, %0\n" : "=g" (esp));
+ asm ("mov %0, %%esp" : "=g" (esp));
return pg_round_down (esp);
}