1 files changed, 9 insertions, 0 deletions
diff --git a/syshead.h b/syshead.h
index e6ced2a..07f1970 100644
--- a/syshead.h
+++ b/syshead.h
@@ -36,6 +36,15 @@
 #endif
 #endif
 
+/* branch prediction hints */
+#if defined(__GNUC__)
+# define likely(x)       __builtin_expect((x),1)
+# define unlikely(x)     __builtin_expect((x),0)
+#else
+# define likely(x)      (x)
+# define unlikely(x)    (x)
+#endif
+
 #if defined(_WIN32) && !defined(WIN32)
 #define WIN32
 #endif