stdarch_internal)Expand description
This module implements minimal run-time feature detection for x86.
The features are detected using the detect_features function below.
This function uses the CPUID instruction to read the feature flags from the
CPU and encodes them in a usize where each bit position represents
whether a feature is available (bit is set) or unavailable (bit is cleared).
The enum Feature is used to map bit positions to feature names, and the
the __crate::detect::check_for! macro is used to map string literals (e.g.,
“avx”) to these bit positions (e.g., Feature::avx).
The run-time feature detection is performed by the
__crate::detect::check_for(Feature) -> bool function. On its first call,
this functions queries the CPU for the available features and stores them
in a global AtomicUsize variable. The query is performed by just checking
whether the feature bit in this global variable is set or cleared.
Modules§
- __
is_ 👻feature_ detected Experimental - Each function performs run-time feature detection for a single feature. This allow us to use stability attributes on a per feature basis.
Enums§
- Feature 🔒👻
Experimental - Each variant denotes a position in a bitset for a particular feature.