Implement exception vectors.

exosphere/lock.h

@@ -0,0 +1,25 @@
+#ifndef EXOSPHERE_LOCK_H
+#define EXOSPHERE_LOCK_H
+
+#include <stdbool.h>
+
+/* Simple atomics driver for Exosphere. */
+
+/* Acquire a lock. */
+static inline void lock_acquire(bool *l) {
+    while (__atomic_test_and_set(l, __ATOMIC_ACQUIRE)) {
+        /* Wait to acquire lock. */
+    }
+}
+
+/* Release a lock. */
+static inline void lock_release(bool *l) {
+    __atomic_clear(l, __ATOMIC_RELEASE);
+}
+
+/* Try to acquire a lock. */
+static inline bool lock_try_acquire(bool *l) {
+    return __atomic_test_and_set(l, __ATOMIC_ACQUIRE);
+}
+
+#endif