Change assembly from AT&T to Intel syntax.

[pintos-anon] / src / threads / thread.c

diff --git a/src/threads/thread.c b/src/threads/thread.c
index afb2006bc1aa8a51ebffc002f80d29e766470e96..01ce7d33227a19196762199f3c349bab4890b688 100644 (file)
--- a/src/threads/thread.c
+++ b/src/threads/thread.c
@@ -59,10 +59,11 @@ void schedule_tail (struct thread *prev);
 static tid_t allocate_tid (void);
 
 /* Initializes the threading system by transforming the code
-   that's currently running into a thread.  Note that this is
-   possible only because the loader was careful to put the bottom
-   of the stack at a page boundary; it won't work in general.
-   Also initializes the run queue.
+   that's currently running into a thread.  This can't work in
+   general and it is possible in this case only because loader.S
+   was careful to put the bottom of the stack at a page boundary.
+
+   Also initializes the run queue and the tid lock.
 
    After calling this function, be sure to initialize the page
    allocator before trying to create any threads with
@@ -169,9 +170,25 @@ thread_create (const char *name, int priority,
   return tid;
 }
 
-/* Transitions a blocked thread T from its current state to the
-   ready-to-run state.  This is an error if T is not blocked.
-   (Use thread_yield() to make the running thread ready.) */
+/* Puts the current thread to sleep.  It will not be scheduled
+   again until awoken by thread_unblock().
+
+   This function must be called with interrupts turned off.  It
+   is usually a better idea to use one of the synchronization
+   primitives in synch.h. */
+void
+thread_block (void) 
+{
+  ASSERT (!intr_context ());
+  ASSERT (intr_get_level () == INTR_OFF);
+
+  thread_current ()->status = THREAD_BLOCKED;
+  schedule ();
+}
+
+/* Transitions a blocked thread T to the ready-to-run state.
+   This is an error if T is not blocked.  (Use thread_yield() to
+   make the running thread ready.) */
 void
 thread_unblock (struct thread *t) 
 {
@@ -254,22 +271,6 @@ thread_yield (void)
   schedule ();
   intr_set_level (old_level);
 }
-
-/* Puts the current thread to sleep.  It will not be scheduled
-   again until awoken by thread_unblock().
-
-   This function must be called with interrupts turned off.  It
-   is usually a better idea to use one of the synchronization
-   primitives in synch.h. */
-void
-thread_block (void) 
-{
-  ASSERT (!intr_context ());
-  ASSERT (intr_get_level () == INTR_OFF);
-
-  thread_current ()->status = THREAD_BLOCKED;
-  schedule ();
-}
 \f
 /* Idle thread.  Executes when no other thread is ready to run. */
 static void
@@ -284,7 +285,8 @@ idle (void *aux UNUSED)
       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");
     }
 }
@@ -310,7 +312,7 @@ running_thread (void)
      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);
 }
 
@@ -375,6 +377,10 @@ next_thread_to_run (void)
    the first time a thread is scheduled it is called by
    switch_entry() (see switch.S).
 
+   It's not safe to call printf() until the thread switch is
+   complete.  In practice that means that printf()s should be
+   added at the end of the function.
+
    After this function and its caller returns, the thread switch
    is complete. */
 void
@@ -406,7 +412,10 @@ schedule_tail (struct thread *prev)
 /* Schedules a new process.  At entry, interrupts must be off and
    the running process's state must have been changed from
    running to some other state.  This function finds another
-   thread to run and switches to it. */
+   thread to run and switches to it.
+
+   It's not safe to call printf() until schedule_tail() has
+   completed. */
 static void
 schedule (void) 
 {