Switch from GPLv2 to GPLv2+

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

diff --git a/src/kernel/ao_mutex.c b/src/kernel/ao_mutex.c
index 952ff46214a69db9b3e293992ee4f2e602576f46..ff73e3bc6998410e29bafbdcc459ba305e0fd7a3 100644 (file)
--- a/src/kernel/ao_mutex.c
+++ b/src/kernel/ao_mutex.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
@@ -17,6 +18,29 @@
 
 #include "ao.h"
 
+#ifndef HAS_MUTEX_TRY
+#define HAS_MUTEX_TRY 1
+#endif
+
+#if HAS_MUTEX_TRY
+
+uint8_t
+ao_mutex_try(__xdata uint8_t *mutex, uint8_t task_id) __reentrant
+{
+       uint8_t ret;
+       if (*mutex == task_id)
+               ao_panic(AO_PANIC_MUTEX);
+       ao_arch_critical(
+               if (*mutex)
+                       ret = 0;
+               else {
+                       *mutex = task_id;
+                       ret = 1;
+               });
+       return ret;
+}
+#endif
+
 void
 ao_mutex_get(__xdata uint8_t *mutex) __reentrant
 {