Added new semaphore API chSemSetCounterI().

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@2569 35acf78f-673a-0410-8e92-d51de3d6d3f4

1 files changed, 32 insertions, 0 deletions

diff --git a/os/kernel/src/chsem.c b/os/kernel/src/chsem.c
index 3e1d2ce88..18ea9e996 100644
--- a/os/kernel/src/chsem.c
+++ b/os/kernel/src/chsem.c
@@ -311,6 +311,38 @@ void chSemSignalI(Semaphore *sp) {
   }

 }

 

+/**

+ * @brief   Sets the semaphore counter to the specified value.

+ * @post    After invoking this function all the threads waiting on the

+ *          semaphore, if any, are released and the semaphore counter is set

+ *          to the specified, non negative, value.

+ * @post    This function does not reschedule so a call to a rescheduling

+ *          function must be performed before unlocking the kernel. Note that

+ *          interrupt handlers always reschedule on exit so an explicit

+ *          reschedule must not be performed in ISRs.

+ *

+ * @param[in] sp        pointer to a @p Semaphore structure

+ * @param[in] n         the new value of the semaphore counter. The value must

+ *                      be non-negative.

+ *

+ * @iclass

+ */

+void chSemSetCounterI(Semaphore *sp, cnt_t n) {

+  cnt_t cnt;

+

+  chDbgCheck((sp != NULL) && (n >= 0), "chSemSetCounterI");

+

+  chDbgAssert(((sp->s_cnt >= 0) && isempty(&sp->s_queue)) ||

+              ((sp->s_cnt < 0) && notempty(&sp->s_queue)),

+              "chSemSetCounterI(), #1",

+              "inconsistent semaphore");

+

+  cnt = sp->s_cnt;

+  sp->s_cnt = n;

+  while (++cnt <= 0)

+    chSchReadyI(lifo_remove(&sp->s_queue))->p_u.rdymsg = RDY_OK;

+}

+

 #if CH_USE_SEMSW

 /**

  * @brief   Performs atomic signal and wait operations on two semaphores.