mmmmh

bits.h

@@ -0,0 +1,34 @@
+#pragma once
+
+#include "collatypes.h"
+
+uint32 bitsCtz(uint32 v);
+
+// == INLINE IMPLEMENTATION ==============================================================
+
+#if COLLA_MSVC
+#define BITS_WIN 1
+#define BITS_LIN 0
+#include <intrin.h>
+#elif COLLA_GCC || COLLA_CLANG || COLLA_EMC
+#define BITS_WIN 0
+#define BITS_LIN 1
+#else
+#error "bits header not supported on this compiler"
+#endif
+
+#include "tracelog.h"
+
+inline uint32 bitsCtz(uint32 v) {
+#if BITS_LIN
+    return v ? __builtin_ctz(v) : 0;
+#elif BITS_WIN
+    uint32 trailing = 0;
+    return _BitScanForward((unsigned long *)&trailing, v) ? trailing : 0;
+#else
+    return 0;
+#endif
+}
+
+#undef BITS_WIN
+#undef BITS_LIN