clz_binary_search.c

#include <stdint.h>

/*It use the 4byte * 2*/

int clz( uint32_t x){
	if( x == 0)	return 32;

	int n = 0;

	if( x <= 0x0000FFFF) { n += 16; x <<= 16;}
	if( x <= 0x00FFFFFF) { n +=  8; x <<=  8;}
	if( x <= 0x0FFFFFFF) { n +=  4; x <<=  4;}
	if( x <= 0x3FFFFFFF) { n +=  2; x <<=  2;}
	if( x <= 0x7FFFFFFF) { n +=  1; x <<=  1;}

	return n;
}