use AVX for DHT

Identity.cpp

@@ -593,11 +593,25 @@ namespace data
 	XORMetric operator^(const IdentHash& key1, const IdentHash& key2)
 	{
 		XORMetric m;
+#if defined(__AVX__) // for AVX
+		__asm__
+		(
+			"vmovups %1, %%ymm0 \n"	
+			"vmovups %2, %%ymm1 \n"	
+			"vxorps %%ymm0, %%ymm1, %%ymm1 \n"
+			"vmovups %%ymm1, %0 \n"
+			: "=m"(*m.metric) 
+			: "m"(*key1), "m"(*key2)
+			: "memory", "%xmm0", "%xmm1" // should be replaced by %ymm0/1 once supported by compiler
+		);			
+#else
 		const uint64_t * hash1 = key1.GetLL (), * hash2 = key2.GetLL ();
 		m.metric_ll[0] = hash1[0] ^ hash2[0];
 		m.metric_ll[1] = hash1[1] ^ hash2[1];
 		m.metric_ll[2] = hash1[2] ^ hash2[2];
 		m.metric_ll[3] = hash1[3] ^ hash2[3];
+#endif
+
 		return m;
 	}	
 }