Index: libcfa/src/bits/defs.hfa
===================================================================
--- libcfa/src/bits/defs.hfa	(revision 21184e35c95906b4f4b5d8d24b90d618f3381310)
+++ libcfa/src/bits/defs.hfa	(revision 7768b8df58110d321b6431c9d8728f39b7d92f86)
@@ -53,2 +53,36 @@
     return ( (unsigned long long)lo)|( ((unsigned long long)hi)<<32 );
 }
+
+#define __CFA_NO_BIT_TEST_AND_SET__
+
+static inline bool bts(volatile unsigned long long int * target, unsigned long long int bit ) {
+	#if defined(__CFA_NO_BIT_TEST_AND_SET__)
+        unsigned long long int mask = 1ul << bit;
+        unsigned long long int ret = __atomic_fetch_or(target, mask, (int)__ATOMIC_RELAXED);
+        return (ret & mask) != 0;
+    #else
+        int result = 0;
+        asm volatile(
+            "LOCK btsq %[bit], %[target]\n\t"
+            :"=@ccc" (result)
+            : [target] "m" (*target), [bit] "r" (bit)
+        );
+        return result != 0;
+    #endif
+}
+
+static inline bool btr(volatile unsigned long long int * target, unsigned long long int bit ) {
+	#if defined(__CFA_NO_BIT_TEST_AND_SET__)
+        unsigned long long int mask = 1ul << bit;
+        unsigned long long int ret = __atomic_fetch_and(target, ~mask, (int)__ATOMIC_RELAXED);
+        return (ret & mask) != 0;
+	#else
+        int result = 0;
+        asm volatile(
+            "LOCK btrq %[bit], %[target]\n\t"
+            :"=@ccc" (result)
+            : [target] "m" (*target), [bit] "r" (bit)
+        );
+        return result != 0;
+    #endif
+}