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//! cls
/// Count leading sign bits
pub trait Cls {
/// Counts the leading most significant bits set.
///
/// When all bits of the operand are set it returns the size of the
/// operand in bits.
///
/// **Keywords**: count leading sign bits, count leading ones, count
/// leading bits set.
///
/// # Instructions
///
/// - [`CLS`](http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0487a.k_10775/index.html):
/// - Description: Count leading sign bits.
/// - Architecture: ARMv8.
/// - Registers: 32/64 bits.
///
/// # Example
///
/// ```
/// # use bitintr::*;
/// let n = 0b1111_1111_1100_1010_u16;
/// assert_eq!(n.cls(), 9);
/// assert_eq!(0b1111_1111_u8.cls(), 7);
/// ```
fn cls(self) -> Self;
}
macro_rules! impl_cls {
($id:ident, $sid:ident, $width:expr) => {
impl Cls for $id {
#[inline]
fn cls(self) -> Self {
$id::leading_zeros((((((self as $sid) >> ($width - 1)) as $id) ^ self) << 1) | 1) as $id
}
}
};
}
impl_cls!(u8, i8, 8);
impl_cls!(i8, i8, 8);
impl_cls!(u16, i16, 16);
impl_cls!(i16, i16, 16);
impl_cls!(u32, i32, 32);
impl_cls!(i32, i32, 32);
impl_cls!(u64, i64, 64);
impl_cls!(i64, i64, 64);