\r
@param Operand The 64-bit operand to evaluate.\r
\r
- @return Position of the highest bit set in Operand if found.\r
- @retval -1 Operand is zero.\r
+ @retval 0..63 Position of the highest bit set in Operand if found.\r
+ @retval -1 Operand is zero.\r
\r
**/\r
INTN\r