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//! Run-time feature detection for PowerPC on Linux.
use super::{auxvec, cpuinfo};
use crate::detect::{cache, Feature};
/// Performs run-time feature detection.
#[inline]
pub fn check_for(x: Feature) -> bool {
cache::test(x as u32, detect_features)
}
/// Try to read the features from the auxiliary vector, and if that fails, try
/// to read them from /proc/cpuinfo.
fn detect_features() -> cache::Initializer {
let mut value = cache::Initializer::default();
let enable_feature = |value: &mut cache::Initializer, f, enable| {
if enable {
value.set(f as u32);
}
};
// The values are part of the platform-specific [asm/cputable.h][cputable]
//
// [cputable]: https://github.com/torvalds/linux/blob/master/arch/powerpc/include/uapi/asm/cputable.h
if let Ok(auxv) = auxvec::auxv() {
// note: the PowerPC values are the mask to do the test (instead of the
// index of the bit to test like in ARM and Aarch64)
enable_feature(&mut value, Feature::altivec, auxv.hwcap & 0x10000000 != 0);
enable_feature(&mut value, Feature::vsx, auxv.hwcap & 0x00000080 != 0);
enable_feature(&mut value, Feature::power8, auxv.hwcap2 & 0x80000000 != 0);
return value;
}
// PowerPC's /proc/cpuinfo lacks a proper Feature field,
// but `altivec` support is indicated in the `cpu` field.
if let Ok(c) = cpuinfo::CpuInfo::new() {
enable_feature(&mut value, Feature::altivec, c.field("cpu").has("altivec"));
return value;
}
value
}
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