Source code
Revision control
Copy as Markdown
Other Tools
↩
#[cfg(not(any(all(↩
target_arch = "spirv",↩
not(all(↩
target_feature = "IntegerFunctions2INTEL",↩
target_feature = "SPV_INTEL_shader_integer_functions2"↩
))↩
))))]↩
#[inline]↩
pub(crate) const fn leading_zeros_u16(x: u16) -> u32 {↩
x.leading_zeros()↩
}↩
↩
#[cfg(all(↩
target_arch = "spirv",↩
not(all(↩
target_feature = "IntegerFunctions2INTEL",↩
target_feature = "SPV_INTEL_shader_integer_functions2"↩
))↩
))]↩
#[inline]↩
pub(crate) const fn leading_zeros_u16(x: u16) -> u32 {↩
leading_zeros_u16_fallback(x)↩
}↩
↩
#[cfg(any(↩
test,↩
all(↩
target_arch = "spirv",↩
not(all(↩
target_feature = "IntegerFunctions2INTEL",↩
target_feature = "SPV_INTEL_shader_integer_functions2"↩
))↩
)↩
))]↩
#[inline]↩
const fn leading_zeros_u16_fallback(mut x: u16) -> u32 {↩
use crunchy::unroll;↩
let mut c = 0;↩
let msb = 1 << 15;↩
unroll! { for i in 0 .. 16 {↩
if x & msb == 0 {↩
c += 1;↩
} else {↩
return c;↩
}↩
#[allow(unused_assignments)]↩
if i < 15 {↩
x <<= 1;↩
}↩
}}↩
c↩
}↩
↩
#[cfg(test)]↩
mod test {↩
↩
#[test]↩
fn leading_zeros_u16_fallback() {↩
for x in [44, 97, 304, 1179, 23571] {↩
assert_eq!(super::leading_zeros_u16_fallback(x), x.leading_zeros());↩
}↩
}↩
}↩