1 #ifdef _MSC_VER
2 
3 #include <intrin.h>
__builtin_clz(unsigned int value)4 int __builtin_clz(unsigned int value)
5 {
6 	unsigned long r;
7 	_BitScanReverse(&r, value);
8 	return (31 - r);
9 }
10 
11 #endif
12