* Returns 0 if no bit is set, else returns the position of the most
* significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit).
*/
* Returns 0 if no bit is set, else returns the position of the most
* significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit).
*/