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    //! 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 an `usize` where each bit position represents
    //! whether a feature is available (bit is set) or unavaiable (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.

    features! {
        @TARGET: x86;
        @MACRO_NAME: is_x86_feature_detected;
        @MACRO_ATTRS:
        /// A macro to test at *runtime* whether a CPU feature is available on
        /// x86/x86-64 platforms.
        ///
        /// This macro is provided in the standard library and will detect at runtime
        /// whether the specified CPU feature is detected. This does **not** resolve at
        /// compile time unless the specified feature is already enabled for the entire
        /// crate. Runtime detection currently relies mostly on the `cpuid` instruction.
        ///
        /// This macro only takes one argument which is a string literal of the feature
        /// being tested for. The feature names supported are the lowercase versions of
        /// the ones defined by Intel in [their documentation][docs].
        ///
        /// ## Supported arguments
        ///
        /// This macro supports the same names that `#[target_feature]` supports. Unlike
        /// `#[target_feature]`, however, this macro does not support names separated
        /// with a comma. Instead testing for multiple features must be done through
        /// separate macro invocations for now.
        ///
        /// Supported arguments are:
        ///
        /// * `"aes"`
        /// * `"pclmulqdq"`
        /// * `"rdrand"`
        /// * `"rdseed"`
        /// * `"tsc"`
        /// * `"mmx"`
        /// * `"sse"`
        /// * `"sse2"`
        /// * `"sse3"`
        /// * `"ssse3"`
        /// * `"sse4.1"`
        /// * `"sse4.2"`
        /// * `"sse4a"`
        /// * `"sha"`
        /// * `"avx"`
        /// * `"avx2"`
        /// * `"avx512f"`
        /// * `"avx512cd"`
        /// * `"avx512er"`
        /// * `"avx512pf"`
        /// * `"avx512bw"`
        /// * `"avx512dq"`
        /// * `"avx512vl"`
        /// * `"avx512ifma"`
        /// * `"avx512vbmi"`
        /// * `"avx512vpopcntdq"`
        /// * `"fma"`
        /// * `"bmi1"`
        /// * `"bmi2"`
        /// * `"abm"`
        /// * `"lzcnt"`
        /// * `"tbm"`
        /// * `"popcnt"`
        /// * `"fxsr"`
        /// * `"xsave"`
        /// * `"xsaveopt"`
        /// * `"xsaves"`
        /// * `"xsavec"`
        ///
        /// [docs]: https://software.intel.com/sites/landingpage/IntrinsicsGuide
        #[stable(feature = "simd_x86", since = "1.27.0")]
        @BIND_FEATURE_NAME: "abm"; "lzcnt"; // abm is a synonym for lzcnt
        @FEATURE: #[stable(feature = "simd_x86", since = "1.27.0")] aes: "aes";
        /// AES (Advanced Encryption Standard New Instructions AES-NI)
        @FEATURE: #[stable(feature = "simd_x86", since = "1.27.0")] pclmulqdq: "pclmulqdq";
        /// CLMUL (Carry-less Multiplication)
        @FEATURE: #[stable(feature = "simd_x86", since = "1.27.0")]  rdrand: "rdrand";
        /// RDRAND
        @FEATURE: #[stable(feature = "simd_x86", since = "1.27.0")] rdseed: "rdseed";
        /// RDSEED
        @FEATURE: #[stable(feature = "simd_x86", since = "1.27.0")] tsc: "tsc";
        /// TSC (Time Stamp Counter)
        @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] mmx: "mmx";
        /// MMX (MultiMedia eXtensions)
        @FEATURE: #[stable(feature = "simd_x86", since = "1.27.0")] sse: "sse";
        /// SSE (Streaming SIMD Extensions)
        @FEATURE: #[stable(feature = "simd_x86", since = "1.27.0")] sse2: "sse2";
        /// SSE2 (Streaming SIMD Extensions 2)
        @FEATURE: #[stable(feature = "simd_x86", since = "1.27.0")] sse3: "sse3";
        /// SSE3 (Streaming SIMD Extensions 3)
        @FEATURE: #[stable(feature = "simd_x86", since = "1.27.0")] ssse3: "ssse3";
        /// SSSE3 (Supplemental Streaming SIMD Extensions 3)
        @FEATURE: #[stable(feature = "simd_x86", since = "1.27.0")] sse4_1: "sse4.1";
        /// SSE4.1 (Streaming SIMD Extensions 4.1)
        @FEATURE: #[stable(feature = "simd_x86", since = "1.27.0")] sse4_2: "sse4.2";
        /// SSE4.2 (Streaming SIMD Extensions 4.2)
        @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] sse4a: "sse4a";
        /// SSE4a (Streaming SIMD Extensions 4a)
        @FEATURE: #[stable(feature = "simd_x86", since = "1.27.0")] sha: "sha";
        /// SHA
        @FEATURE: #[stable(feature = "simd_x86", since = "1.27.0")] avx: "avx";
        /// AVX (Advanced Vector Extensions)
        @FEATURE: #[stable(feature = "simd_x86", since = "1.27.0")] avx2: "avx2";
        /// AVX2 (Advanced Vector Extensions 2)
        @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] avx512f: "avx512f" ;
        /// AVX-512 F (Foundation)
        @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] avx512cd: "avx512cd" ;
        /// AVX-512 CD (Conflict Detection Instructions)
        @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] avx512er: "avx512er";
        /// AVX-512 ER (Expo nential and Reciprocal Instructions)
        @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] avx512pf: "avx512pf";
        /// AVX-512 PF (Prefetch Instructions)
        @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] avx512bw: "avx512bw";
        /// AVX-512 BW (Byte and Word Instructions)
        @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] avx512dq: "avx512dq";
        /// AVX-512 DQ (Doubleword and Quadword)
        @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] avx512vl: "avx512vl";
        /// AVX-512 VL (Vector Length Extensions)
        @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] avx512ifma: "avx512ifma";
        /// AVX-512 IFMA (Integer Fused Multiply Add)
        @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] avx512vbmi: "avx512vbmi";
        /// AVX-512 VBMI (Vector Byte Manipulation Instructions)
        @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] avx512vpopcntdq: "avx512vpopcntdq";
        /// AVX-512 VPOPCNTDQ (Vector Population Count Doubleword and
        /// Quadword)
        @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] avx512vbmi2: "avx512vbmi2";
        /// AVX-512 VBMI2 (Additional byte, word, dword and qword capabilities)
        @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] avx512gfni: "avx512gfni";
        /// AVX-512 GFNI (Galois Field New Instruction)
        @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] avx512vaes: "avx512vaes";
        /// AVX-512 VAES (Vector AES instruction)
        @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] avx512vpclmulqdq: "avx512vpclmulqdq";
        /// AVX-512 VPCLMULQDQ (Vector PCLMULQDQ instructions)
        @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] avx512vnni: "avx512vnni";
        /// AVX-512 VNNI (Vector Neural Network Instructions)
        @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] avx512bitalg: "avx512bitalg";
        /// AVX-512 BITALG (Support for VPOPCNT[B,W] and VPSHUFBITQMB)
        @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] avx512bf16: "avx512bf16";
        /// AVX-512 BF16 (BFLOAT16 instructions)
        @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] avx512vp2intersect: "avx512vp2intersect";
        /// AVX-512 P2INTERSECT
        @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] f16c: "f16c";
        /// F16C (Conversions between IEEE-754 `binary16` and `binary32` formats)
        @FEATURE: #[stable(feature = "simd_x86", since = "1.27.0")] fma: "fma";
        /// FMA (Fused Multiply Add)
        @FEATURE: #[stable(feature = "simd_x86", since = "1.27.0")] bmi1: "bmi1" ;
        /// BMI1 (Bit Manipulation Instructions 1)
        @FEATURE: #[stable(feature = "simd_x86", since = "1.27.0")] bmi2: "bmi2" ;
        /// BMI2 (Bit Manipulation Instructions 2)
        @FEATURE: #[stable(feature = "simd_x86", since = "1.27.0")] lzcnt: "lzcnt";
        /// ABM (Advanced Bit Manipulation) / LZCNT (Leading Zero Count)
        @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] tbm: "tbm";
        /// TBM (Trailing Bit Manipulation)
        @FEATURE: #[stable(feature = "simd_x86", since = "1.27.0")] popcnt: "popcnt";
        /// POPCNT (Population Count)
        @FEATURE: #[stable(feature = "simd_x86", since = "1.27.0")] fxsr: "fxsr";
        /// FXSR (Floating-point context fast save and restor)
        @FEATURE: #[stable(feature = "simd_x86", since = "1.27.0")] xsave: "xsave";
        /// XSAVE (Save Processor Extended States)
        @FEATURE: #[stable(feature = "simd_x86", since = "1.27.0")] xsaveopt: "xsaveopt";
        /// XSAVEOPT (Save Processor Extended States Optimized)
        @FEATURE: #[stable(feature = "simd_x86", since = "1.27.0")] xsaves: "xsaves";
        /// XSAVES (Save Processor Extended States Supervisor)
        @FEATURE: #[stable(feature = "simd_x86", since = "1.27.0")] xsavec: "xsavec";
        /// XSAVEC (Save Processor Extended States Compacted)
        @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] cmpxchg16b: "cmpxchg16b";
        /// CMPXCH16B (16-byte compare-and-swap instruction)
        @FEATURE: #[stable(feature = "simd_x86_adx", since = "1.33.0")] adx: "adx";
        /// ADX, Intel ADX (Multi-Precision Add-Carry Instruction Extensions)
        @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] rtm: "rtm";
        /// RTM, Intel (Restricted Transactional Memory)
    }