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authorLennart Poettering <lennart@poettering.net>2007-09-04 20:00:19 +0000
committerLennart Poettering <lennart@poettering.net>2007-09-04 20:00:19 +0000
commit2dbe137daf8c74feca75ead33d5f8fbc84544af1 (patch)
treef560ceb29811636f9bb302e43da156dd6b3af748
parent31c04a9047e609764a374ebacbadfaaa470aaa3e (diff)
if available, use native gcc atomicity builtins
git-svn-id: file:///home/lennart/svn/public/pulseaudio/branches/lennart@1767 fefdeb5f-60dc-0310-8127-8f9354f1896f
-rw-r--r--src/pulsecore/atomic.h93
1 files changed, 84 insertions, 9 deletions
diff --git a/src/pulsecore/atomic.h b/src/pulsecore/atomic.h
index 9a024f91..b5c1ad9e 100644
--- a/src/pulsecore/atomic.h
+++ b/src/pulsecore/atomic.h
@@ -24,22 +24,95 @@
USA.
***/
-#include <atomic_ops.h>
-
-/* atomic_ops guarantees us that sizeof(AO_t) == sizeof(void*).
+/*
+ * atomic_ops guarantees us that sizeof(AO_t) == sizeof(void*). It is
+ * not guaranteed however, that sizeof(AO_t) == sizeof(size_t).
+ * however very likely.
+ *
+ * For now we do only full memory barriers. Eventually we might want
+ * to support more elaborate memory barriers, in which case we will add
+ * suffixes to the function names.
*
- * It is not guaranteed however, that sizeof(AO_t) == sizeof(size_t).
- * however very likely. */
+ * On gcc >= 4.1 we use the builtin atomic functions. otherwise we use
+ * libatomic_ops
+ */
+
+#if defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1))
+
+/* gcc based implementation */
typedef struct pa_atomic {
- volatile AO_t value;
+ volatile int value;
} pa_atomic_t;
#define PA_ATOMIC_INIT(v) { .value = (v) }
-/* For now we do only full memory barriers. Eventually we might want
- * to support more elaborate memory barriers, in which case we will add
- * suffixes to the function names */
+static inline int pa_atomic_load(const pa_atomic_t *a) {
+ __sync_synchronize();
+ return a->value;
+}
+
+static inline void pa_atomic_store(pa_atomic_t *a, int i) {
+ a->value = i;
+ __sync_synchronize();
+}
+
+/* Returns the previously set value */
+static inline int pa_atomic_add(pa_atomic_t *a, int i) {
+ return __sync_fetch_and_add(&a->value, i);
+}
+
+/* Returns the previously set value */
+static inline int pa_atomic_sub(pa_atomic_t *a, int i) {
+ return __sync_fetch_and_sub(&a->value, i);
+}
+
+/* Returns the previously set value */
+static inline int pa_atomic_inc(pa_atomic_t *a) {
+ return pa_atomic_add(a, 1);
+}
+
+/* Returns the previously set value */
+static inline int pa_atomic_dec(pa_atomic_t *a) {
+ return pa_atomic_sub(a, 1);
+}
+
+/* Returns non-zero when the operation was successful. */
+static inline int pa_atomic_cmpxchg(pa_atomic_t *a, int old_i, int new_i) {
+ return __sync_bool_compare_and_swap(&a->value, old_i, new_i);
+}
+
+typedef struct pa_atomic_ptr {
+ volatile long value;
+} pa_atomic_ptr_t;
+
+#define PA_ATOMIC_PTR_INIT(v) { .value = (long) (v) }
+
+static inline void* pa_atomic_ptr_load(const pa_atomic_ptr_t *a) {
+ __sync_synchronize();
+ return (void*) a->value;
+}
+
+static inline void pa_atomic_ptr_store(pa_atomic_ptr_t *a, void *p) {
+ a->value = (long) p;
+ __sync_synchronize();
+}
+
+static inline int pa_atomic_ptr_cmpxchg(pa_atomic_ptr_t *a, void *old_p, void* new_p) {
+ return __sync_bool_compare_and_swap(&a->value, (long) old_p, (long) new_p);
+}
+
+#else
+
+/* libatomic_ops based implementation */
+
+#include <atomic_ops.h>
+
+typedef struct pa_atomic {
+ volatile AO_t value;
+} pa_atomic_t;
+
+#define PA_ATOMIC_INIT(v) { .value = (v) }
static inline int pa_atomic_load(const pa_atomic_t *a) {
return (int) AO_load_full((AO_t*) &a->value);
@@ -88,3 +161,5 @@ static inline int pa_atomic_ptr_cmpxchg(pa_atomic_ptr_t *a, void *old_p, void* n
}
#endif
+
+#endif