X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Fdevices%2Ftimer.c;h=ecf6c5aacdfee97c6577c8b60912475ef99e4e77;hb=64f0952217e8b1a53461f5a98a070cb2da266171;hp=200d58f8251e0b660bd3a4fa49367b337a882857;hpb=208fb587faa75eaa0e740db9b605ff3d7ba24905;p=pintos-anon

diff --git a/src/devices/timer.c b/src/devices/timer.c
index 200d58f..ecf6c5a 100644
--- a/src/devices/timer.c
+++ b/src/devices/timer.c
@@ -1,10 +1,14 @@
 #include "devices/timer.h"
 #include <debug.h>
+#include <inttypes.h>
 #include <round.h>
+#include <stdio.h>
 #include "threads/interrupt.h"
 #include "threads/io.h"
 #include "threads/thread.h"
   
+/* See [8254] for hardware details of the 8254 timer chip. */
+
 #if TIMER_FREQ < 19
 #error 8254 timer requires TIMER_FREQ >= 19
 #endif
@@ -21,7 +25,7 @@ static volatile int64_t ticks;
 
 static intr_handler_func timer_interrupt;
 
-/* Sets up the 8254 Programmable Interrupt Timer (PIT) to
+/* Sets up the 8254 Programmable Interval Timer (PIT) to
    interrupt PIT_FREQ times per second, and registers the
    corresponding interrupt. */
 void
@@ -62,9 +66,9 @@ timer_sleep (int64_t ticks)
 {
   int64_t start = timer_ticks ();
 
+  ASSERT (intr_get_level () == INTR_ON);
   while (timer_elapsed (start) < ticks) 
-    if (intr_get_level () == INTR_ON)
-      thread_yield ();
+    thread_yield ();
 }
 
 /* Returns MS milliseconds in timer ticks, rounding up. */
@@ -91,12 +95,20 @@ timer_ns2ticks (int64_t ns)
 {
   return DIV_ROUND_UP (ns * TIMER_FREQ, 1000000000);
 }
+
+/* Prints timer statistics. */
+void
+timer_print_stats (void) 
+{
+  printf ("Timer: %"PRId64" ticks\n", ticks);
+}
 
 /* Timer interrupt handler. */
 static void
 timer_interrupt (struct intr_frame *args UNUSED)
 {
   ticks++;
+  thread_tick ();
   if (ticks % TIME_SLICE == 0)
     intr_yield_on_return ();
 }