1 files changed, 85 insertions, 0 deletions
diff --git a/library/stdarch/crates/core_arch/src/x86/eflags.rs b/library/stdarch/crates/core_arch/src/x86/eflags.rs
new file mode 100644
index 000000000..e9ebdf22b
--- /dev/null
+++ b/library/stdarch/crates/core_arch/src/x86/eflags.rs
@@ -0,0 +1,85 @@
+//! `i386` intrinsics
+
+use crate::arch::asm;
+
+/// 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")]
+#[deprecated(
+    since = "1.29.0",
+    note = "See issue #51810 - use inline assembly instead"
+)]
+#[doc(hidden)]
+pub unsafe fn __readeflags() -> u32 {
+    let eflags: u32;
+    asm!("pushfd", "pop {}", out(reg) eflags, options(nomem, att_syntax));
+    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")]
+#[deprecated(
+    since = "1.29.0",
+    note = "See issue #51810 - use inline assembly instead"
+)]
+#[doc(hidden)]
+pub unsafe fn __readeflags() -> u64 {
+    let eflags: u64;
+    asm!("pushfq", "pop {}", out(reg) eflags, options(nomem, att_syntax));
+    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")]
+#[deprecated(
+    since = "1.29.0",
+    note = "See issue #51810 - use inline assembly instead"
+)]
+#[doc(hidden)]
+pub unsafe fn __writeeflags(eflags: u32) {
+    asm!("push {}", "popfd", in(reg) eflags, options(nomem, att_syntax));
+}
+
+/// 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")]
+#[deprecated(
+    since = "1.29.0",
+    note = "See issue #51810 - use inline assembly instead"
+)]
+#[doc(hidden)]
+pub unsafe fn __writeeflags(eflags: u64) {
+    asm!("push {}", "popfq", in(reg) eflags, options(nomem, att_syntax));
+}
+
+#[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);
+        }
+    }
+}