__get_cpuid_max in core::arch::x86_64 - Rust
Description: Returns the highest-supported `leaf` (`EAX`) and sub-leaf (`ECX`) `cpuid` values.

## __get_cpuid_max

# Function __get_cpuid_max

1.27.0 · Source

    pub unsafe fn __get_cpuid_max(leaf: u32) -> (u32, u32)

Available on x86-64 only.
Expand description

Returns the highest-supported `leaf` (`EAX`) and sub-leaf (`ECX`) `cpuid` values.

If `cpuid` is supported, and `leaf` is zero, then the first tuple argument contains the highest `leaf` value that `cpuid` supports. For `leaf`s containing sub-leafs, the second tuple argument contains the highest-supported sub-leaf value.

See also `__cpuid` and `__cpuid_count`.