1 files changed, 31 insertions, 0 deletions
diff --git a/include/sys/semaphore.h b/include/sys/semaphore.h
new file mode 100644
index 0000000..0a25af3
--- /dev/null
+++ b/include/sys/semaphore.h
@@ -0,0 +1,31 @@
+#include <avr/io.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#ifndef _IOE_SYS_SEMAPHORE_H_
+#define _IOE_SYS_SEMAPHORE_H_
+#ifdef CONFIG_IOE_SEMAPHORE
+
+#define semaphore_t volatile struct Semaphore
+struct Semaphore {
+    uint8_t flags;
+    uint8_t _count;
+    Task **_tasks;
+    uint8_t _tasks_len;
+};
+int8_t semaphore_init(struct Semaphore * sem, uint8_t count);
+int8_t semaphore_free(struct Semaphore * sem);
+int8_t semaphore_take(struct Semaphore * sem, uint16_t timeout);
+int8_t semaphore_give(Semaphore * sem);
+
+#else /* CONFIG_IOE_SEMAPHORE */
+
+#define semaphore_t struct { }
+// TODO implement for single processor
+#define semaphore_init(SEM, FLAGS, COUNT)
+#define semaphore_free(SEM)
+#define semaphore_take(SEM, TIMEOUT)
+#define semaphore_give(SEM)
+
+#endif /* CONFIG_IOE_SEMAPHORE */
+#endif /* _IOE_SYS_SEMAPHORE_H_ */