Added bsr() function to util

2022-05-09 11:25:52 +02:00
parent 820c5db5e8
commit d23c46ff84
6 changed files with 98 additions and 10 deletions
@@ -203,6 +203,22 @@ FORCEINLINE uint64_t seconds_since_epoch()
 	return duration_cast<seconds>(steady_clock::now().time_since_epoch()).count();
 }

+uint64_t bsr_reference(uint64_t x);
+
+#ifdef HAVE_BUILTIN_CLZLL
+#define bsr(x) (63 - __builtin_clzll(x))
+#elif defined HAVE_BITSCANREVERSE64
+#pragma intrinsic(_BitScanReverse64)
+FORCEINLINE uint64_t bsr(uint64_t x)
+{
+	unsigned long index;
+	_BitScanReverse64(&index, x);
+	return index;
+}
+#else
+#define bsr bsr_reference
+#endif
+
 } // namespace p2pool

 namespace robin_hood {