Timer handling code size improvement in tickless mode.

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@9961 35acf78f-673a-0410-8e92-d51de3d6d3f4

1 files changed, 14 insertions, 7 deletions

diff --git a/os/nil/src/ch.c b/os/nil/src/ch.c
index 562259913..7fdf6812f 100644
--- a/os/nil/src/ch.c
+++ b/os/nil/src/ch.c
@@ -326,7 +326,7 @@ void chSysTimerHandlerI(void) {
 

       chDbgAssert(!NIL_THD_IS_READY(tp), "is ready");

 

-     /* Did the timer reach zero?*/

+      /* Did the timer reach zero?*/

       if (--tp->timeout == (systime_t)0) {

         /* Timeout on semaphores requires a special handling because the

            semaphore counter must be incremented.*/

@@ -354,14 +354,19 @@ void chSysTimerHandlerI(void) {
   chDbgAssert(nil.nexttime == port_timer_get_alarm(), "time mismatch");

 

   do {

+    systime_t timeout = tp->timeout;

+

     /* Is the thread in a wait state with timeout?.*/

-    if (tp->timeout > (systime_t)0) {

+    if (timeout > (systime_t)0) {

 

       chDbgAssert(!NIL_THD_IS_READY(tp), "is ready");

-      chDbgAssert(tp->timeout >= (nil.nexttime - nil.lasttime), "skipped one");

+      chDbgAssert(timeout >= (nil.nexttime - nil.lasttime), "skipped one");

+

+      /* The volatile field is updated once, here.*/

+      timeout -= nil.nexttime - nil.lasttime;

+      tp->timeout = timeout;

 

-      tp->timeout -= nil.nexttime - nil.lasttime;

-      if (tp->timeout == (systime_t)0) {

+      if (timeout == (systime_t)0) {

 #if CH_CFG_USE_SEMAPHORES == TRUE

         /* Timeout on semaphores requires a special handling because the

            semaphore counter must be incremented.*/

@@ -379,17 +384,19 @@ void chSysTimerHandlerI(void) {
         (void) chSchReadyI(tp, MSG_TIMEOUT);

       }

       else {

-        if (tp->timeout <= (systime_t)(next - (systime_t)1)) {

-          next = tp->timeout;

+        if (timeout <= (systime_t)(next - (systime_t)1)) {

+          next = timeout;

         }

       }

     }

+

     /* Lock released in order to give a preemption chance on those

        architectures supporting IRQ preemption.*/

     chSysUnlockFromISR();

     tp++;

     chSysLockFromISR();

   } while (tp < &nil.threads[CH_CFG_NUM_THREADS]);

+

   nil.lasttime = nil.nexttime;

   if (next > (systime_t)0) {

     nil.nexttime += next;