* an unsigned 32-bit or 64-bit value without any leading zero bits.
* This can also be thought of as the location of the highest set bit, with
* counting starting from one (so that 0 returns 0, 1 returns 1, and 2**31
* returns 32).
* an unsigned 32-bit or 64-bit value without any leading zero bits.
* This can also be thought of as the location of the highest set bit, with
* counting starting from one (so that 0 returns 0, 1 returns 1, and 2**31
* returns 32).