altos: Perform time comparisons using 16-bit arithmetic to handle wrap

[fw/altos] / src / kernel / ao_flight.c

diff --git a/src/kernel/ao_flight.c b/src/kernel/ao_flight.c
index 9031a54ae070e97e42a6d182e0d4b802e9897918..b0d911ed7f2663ac5b820cc0146d4944da9d2d85 100644 (file)
--- a/src/kernel/ao_flight.c
+++ b/src/kernel/ao_flight.c
@@ -3,7 +3,8 @@
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; version 2 of the License.
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful, but
  * WITHOUT ANY WARRANTY; without even the implied warranty of
@@ -268,7 +269,7 @@ ao_flight(void)
                         * number of seconds.
                         */
                        if (ao_config.apogee_lockout) {
-                               if ((ao_sample_tick - ao_boost_tick) <
+                               if ((int16_t) (ao_sample_tick - ao_boost_tick) <
                                    AO_SEC_TO_TICKS(ao_config.apogee_lockout))
                                        break;
                        }