eflags.rs.html -- source
Description: Source to the Rust file `library/core/src/../../stdarch/crates/core_arch/src/x86/eflags.rs`.
Keywords: rust, rustlang, rust-lang

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    //! `i386` intrinsics

    /// Reads EFLAGS.
    ///
    /// [Intel's documentation](https://software.intel.com/sites/landingpage/IntrinsicsGuide/#text=__readeflags)
    #[cfg(target_arch = "x86")]
    #[inline(always)]
    #[stable(feature = "simd_x86", since = "1.27.0")]
    #[rustc_deprecated(
        since = "1.29.0",
        reason = "See issue #51810 - use inline assembly instead"
    )]
    #[doc(hidden)]
    pub unsafe fn __readeflags() -> u32 {
        let eflags: u32;
        llvm_asm!("pushfd; popl $0" : "=r"(eflags) : : : "volatile");
        eflags
    }

    /// Reads EFLAGS.
    ///
    /// [Intel's documentation](https://software.intel.com/sites/landingpage/IntrinsicsGuide/#text=__readeflags)
    #[cfg(target_arch = "x86_64")]
    #[inline(always)]
    #[stable(feature = "simd_x86", since = "1.27.0")]
    #[rustc_deprecated(
        since = "1.29.0",
        reason = "See issue #51810 - use inline assembly instead"
    )]
    #[doc(hidden)]
    pub unsafe fn __readeflags() -> u64 {
        let eflags: u64;
        llvm_asm!("pushfq; popq $0" : "=r"(eflags) : : : "volatile");
        eflags
    }

    /// Write EFLAGS.
    ///
    /// [Intel's documentation](https://software.intel.com/sites/landingpage/IntrinsicsGuide/#text=__writeeflags)
    #[cfg(target_arch = "x86")]
    #[inline(always)]
    #[stable(feature = "simd_x86", since = "1.27.0")]
    #[rustc_deprecated(
        since = "1.29.0",
        reason = "See issue #51810 - use inline assembly instead"
    )]
    #[doc(hidden)]
    pub unsafe fn __writeeflags(eflags: u32) {
        llvm_asm!("pushl $0; popfd" : : "r"(eflags) : "cc", "flags" : "volatile");
    }

    /// Write EFLAGS.
    ///
    /// [Intel's documentation](https://software.intel.com/sites/landingpage/IntrinsicsGuide/#text=__writeeflags)
    #[cfg(target_arch = "x86_64")]
    #[inline(always)]
    #[stable(feature = "simd_x86", since = "1.27.0")]
    #[rustc_deprecated(
        since = "1.29.0",
        reason = "See issue #51810 - use inline assembly instead"
    )]
    #[doc(hidden)]
    pub unsafe fn __writeeflags(eflags: u64) {
        llvm_asm!("pushq $0; popfq" : : "r"(eflags) : "cc", "flags" : "volatile");
    }

    #[cfg(test)]
    mod tests {
        use crate::core_arch::x86::*;

        #[test]
        #[allow(deprecated)]
        fn test_eflags() {
            unsafe {
                // reads eflags, writes them back, reads them again,
                // and compare for equality:
                let v = __readeflags();
                __writeeflags(v);
                let u = __readeflags();
                assert_eq!(v, u);
            }
        }
    }