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