1 files changed, 30 insertions, 0 deletions
diff --git a/os/rt/src/chthreads.c b/os/rt/src/chthreads.c
index f7694f593..d7e9bc13d 100644
--- a/os/rt/src/chthreads.c
+++ b/os/rt/src/chthreads.c
@@ -311,6 +311,11 @@ void chThdSleep(systime_t time) {
 /**
  * @brief   Suspends the invoking thread until the system time arrives to the
  *          specified value.
+ * @note    The function has no concept of "past", all specifiable times
+ *          are in the future, this means that if you call this function
+ *          exceeding your calculated intervals then the function will
+ *          return in a far future time, not immediately.
+ * @see     chThdSleepUntilWindowed()
  *
  * @param[in] time      absolute system time
  *
@@ -325,6 +330,31 @@ void chThdSleepUntil(systime_t time) {
 }
 
 /**
+ * @brief   Suspends the invoking thread until the system time arrives to the
+ *          specified value.
+ * @note    The system time is assumed to be between @p prev and @p time
+ *          else the call is assumed to have been called outside the
+ *          allowed time interval, in this case no sleep is performed.
+ * @see     chThdSleepUntilWindowed()
+ *
+ * @param[in] prev      absolute system time of the previous deadline
+ * @param[in] next      absolute system time of the next deadline
+ * @return				the @p next parameter
+ *
+ * @api
+ */
+systime_t chThdSleepUntilWindowed(systime_t prev, systime_t next) {
+  systime_t time;
+
+  chSysLock();
+  time = chVTGetSystemTimeX();
+  if (chVTIsTimeWithinX(time, prev, next))
+	chThdSleepS(next - time);
+  chSysUnlock();
+  return next;
+}
+
+/**
  * @brief   Yields the time slot.
  * @details Yields the CPU control to the next thread in the ready list with
  *          equal priority, if any.