//! x86/x86-64 CPU feature detection support.
//!
//! Portable, `no_std`-friendly implementation that relies on the x86 `CPUID`
//! instruction for feature detection.
/// Evaluate the given `$body` expression any of the supplied target features
/// are not enabled. Otherwise returns true.
///
/// The `$body` expression is not evaluated on SGX targets, and returns false
/// on these targets unless *all* supplied target features are enabled.
#[macro_export]
#[doc(hidden)]
macro_rules! __unless_target_features {
($($tf:tt),+ => $body:expr ) => {{
#[cfg(not(all($(target_feature=$tf,)*)))]
{
#[cfg(not(any(target_env = "sgx", target_os = "", target_os = "uefi")))]
$body
// CPUID is not available on SGX. Freestanding and UEFI targets
// do not support SIMD features with default compilation flags.
#[cfg(any(target_env = "sgx", target_os = "", target_os = "uefi"))]
false
}
#[cfg(all($(target_feature=$tf,)*))]
true
}};
}
/// Use CPUID to detect the presence of all supplied target features.
#[macro_export]
#[doc(hidden)]
macro_rules! __detect_target_features {
($($tf:tt),+) => {{
#[cfg(target_arch = "x86")]
use core::arch::x86::{__cpuid, __cpuid_count, CpuidResult};
#[cfg(target_arch = "x86_64")]
use core::arch::x86_64::{__cpuid, __cpuid_count, CpuidResult};
// These wrappers are workarounds around
//
https://github.com/rust-lang/rust/issues/101346
//
// DO NOT remove it until MSRV is bumped to a version
// with the issue fix (at least 1.64).
#[inline(never)]
unsafe fn cpuid(leaf: u32) -> CpuidResult {
__cpuid(leaf)
}
#[inline(never)]
unsafe fn cpuid_count(leaf: u32, sub_leaf: u32) -> CpuidResult {
__cpuid_count(leaf, sub_leaf)
}
let cr = unsafe {
[cpuid(1), cpuid_count(7, 0)]
};
$($crate::check!(cr, $tf) & )+ true
}};
}
/// Check that OS supports required SIMD registers
#[macro_export]
#[doc(hidden)]
macro_rules! __xgetbv {
($cr:expr, $mask:expr) => {{
#[cfg(target_arch = "x86")]
use core::arch::x86 as arch;
#[cfg(target_arch = "x86_64")]
use core::arch::x86_64 as arch;
// Check bits 26 and 27
let xmask = 0b11 << 26;
let xsave = $cr[0].ecx & xmask == xmask;
if xsave {
let xcr0 = unsafe { arch::_xgetbv(arch::_XCR_XFEATURE_ENABLED_MASK) };
(xcr0 & $mask) == $mask
} else {
false
}
}};
}
macro_rules! __expand_check_macro {
($(($name:tt, $reg_cap:tt $(, $i:expr, $reg:ident, $offset:expr)*)),* $(,)?) => {
#[macro_export]
#[doc(hidden)]
macro_rules! check {
$(
($cr:expr, $name) => {{
// Register bits are listed here:
//
https://wiki.osdev.org/CPU_Registers_x86#Extended_Control_Registers
let reg_cap = match $reg_cap {
// Bit 1
"xmm" => $crate::__xgetbv!($cr, 0b10),
// Bits 1 and 2
"ymm" => $crate::__xgetbv!($cr, 0b110),
// Bits 1, 2, 5, 6, and 7
"zmm" => $crate::__xgetbv!($cr, 0b1110_0110),
_ => true,
};
reg_cap
$(
& ($cr[$i].$reg & (1 << $offset) != 0)
)*
}};
)*
}
};
}
__expand_check_macro! {
("sse3", "xmm", 0, ecx, 0),
("pclmulqdq", "xmm", 0, ecx, 1),
("ssse3", "xmm", 0, ecx, 9),
("fma", "xmm", 0, ecx, 12, 0, ecx, 28),
("sse4.1", "xmm", 0, ecx, 19),
("sse4.2", "xmm", 0, ecx, 20),
("popcnt", "", 0, ecx, 23),
("aes", "xmm", 0, ecx, 25),
("avx", "xmm", 0, ecx, 28),
("rdrand", "", 0, ecx, 30),
("mmx", "", 0, edx, 23),
("sse", "xmm", 0, edx, 25),
("sse2", "xmm", 0, edx, 26),
("sgx", "", 1, ebx, 2),
("bmi1", "", 1, ebx, 3),
("bmi2", "", 1, ebx, 8),
("avx2", "ymm", 1, ebx, 5, 0, ecx, 28),
("avx512f", "zmm", 1, ebx, 16),
("avx512dq", "zmm", 1, ebx, 17),
("rdseed", "", 1, ebx, 18),
("adx", "", 1, ebx, 19),
("avx512ifma", "zmm", 1, ebx, 21),
("avx512pf", "zmm", 1, ebx, 26),
("avx512er", "zmm", 1, ebx, 27),
("avx512cd", "zmm", 1, ebx, 28),
("sha", "xmm", 1, ebx, 29),
("avx512bw", "zmm", 1, ebx, 30),
("avx512vl", "zmm", 1, ebx, 31),
}
