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

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

diff --git a/src/kernel/ao_sample.c b/src/kernel/ao_sample.c
index 29bf2bf6ed0661a98aab90182b903977c1148880..f0ab0169805fb6a1db38ddde5ca7b803b2f530c9 100644 (file)
--- a/src/kernel/ao_sample.c
+++ b/src/kernel/ao_sample.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
@@ -179,7 +180,7 @@ static void
 ao_sample_rotate(void)
 {
 #ifdef AO_FLIGHT_TEST
-       float   dt = (ao_sample_tick - ao_sample_prev_tick) / TIME_DIV;
+       float   dt = (int16_t) (ao_sample_tick - ao_sample_prev_tick) / TIME_DIV;
 #else
        static const float dt = 1/TIME_DIV;
 #endif