library/stdarch/crates/std_detect/src/detect/os/linux/powerpc.rs

   1 //! Run-time feature detection for PowerPC on Linux.
   2
   3 use super::auxvec;
   4 use crate::detect::{cache, Feature};
   5
   6 /// Try to read the features from the auxiliary vector, and if that fails, try
   7 /// to read them from /proc/cpuinfo.
   8 pub(crate) fn detect_features() -> cache::Initializer {
   9     let mut value = cache::Initializer::default();
  10     let enable_feature = |value: &mut cache::Initializer, f, enable| {
  11         if enable {
  12             value.set(f as u32);
  13         }
  14     };
  15
  16     // The values are part of the platform-specific [asm/cputable.h][cputable]
  17     //
  18     // [cputable]: https://github.com/torvalds/linux/blob/master/arch/powerpc/include/uapi/asm/cputable.h
  19     if let Ok(auxv) = auxvec::auxv() {
  20         // note: the PowerPC values are the mask to do the test (instead of the
  21         // index of the bit to test like in ARM and Aarch64)
  22         enable_feature(&mut value, Feature::altivec, auxv.hwcap & 0x10000000 != 0);
  23         enable_feature(&mut value, Feature::vsx, auxv.hwcap & 0x00000080 != 0);
  24         enable_feature(&mut value, Feature::power8, auxv.hwcap2 & 0x80000000 != 0);
  25         return value;
  26     }
  27
  28     // PowerPC's /proc/cpuinfo lacks a proper Feature field,
  29     // but `altivec` support is indicated in the `cpu` field.
  30     #[cfg(feature = "std_detect_file_io")]
  31     if let Ok(c) = super::cpuinfo::CpuInfo::new() {
  32         enable_feature(&mut value, Feature::altivec, c.field("cpu").has("altivec"));
  33         return value;
  34     }
  35     value
  36 }