Crate cpuid_bool

Macro for checking CPU capabilities at runtime.

Example

// This macro creates `cpuid_aes_sha` module
cpuid_bool::new!(cpuid_aes_sha, "aes", "sha");

// `token` is a Zero Sized Type value, which guarantees
// that underlying static storage got properly initialized,
// which allows to omit initialization branch
let token: cpuid_aes_sha::InitToken = cpuid_aes_sha::init();
if token.get() {
    println!("CPU supports both SHA and AES extensions");
} else {
    println!("SHA and AES extensions are not supported");
}

// If stored value needed only once you can get stored value
// omitting the token
let val = cpuid_aes_sha::get();
assert_eq!(val, token.get());

// Additionally you can get both token and value
let (token, val) = cpuid_aes_sha::init_get();
assert_eq!(val, token.get());

Note that if all tested target features are enabled via compiler options (e.g. by using RUSTFLAGS), the get method will always return true and init will not use CPUID instruction. Such behavior allows compiler to completely eliminate fallback code.

After first call macro caches result and returns it in subsequent calls, thus runtime overhead for them is minimal.

Macros

new	Create module with CPUID bool code.