1 files changed, 59 insertions, 0 deletions
diff --git a/library/stdarch/crates/std_detect/src/detect/os/windows/aarch64.rs b/library/stdarch/crates/std_detect/src/detect/os/windows/aarch64.rs
new file mode 100644
index 000000000..051ad6d1b
--- /dev/null
+++ b/library/stdarch/crates/std_detect/src/detect/os/windows/aarch64.rs
@@ -0,0 +1,59 @@
+//! Run-time feature detection for Aarch64 on Windows.
+
+use crate::detect::{cache, Feature};
+
+/// Try to read the features using IsProcessorFeaturePresent.
+pub(crate) fn detect_features() -> cache::Initializer {
+    type DWORD = u32;
+    type BOOL = i32;
+
+    const FALSE: BOOL = 0;
+    // The following Microsoft documents isn't updated for aarch64.
+    // https://docs.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-isprocessorfeaturepresent
+    // These are defined in winnt.h of Windows SDK
+    const PF_ARM_NEON_INSTRUCTIONS_AVAILABLE: u32 = 19;
+    const PF_ARM_V8_CRYPTO_INSTRUCTIONS_AVAILABLE: u32 = 30;
+    const PF_ARM_V8_CRC32_INSTRUCTIONS_AVAILABLE: u32 = 31;
+
+    extern "system" {
+        pub fn IsProcessorFeaturePresent(ProcessorFeature: DWORD) -> BOOL;
+    }
+
+    let mut value = cache::Initializer::default();
+    {
+        let mut enable_feature = |f, enable| {
+            if enable {
+                value.set(f as u32);
+            }
+        };
+
+        // Some features such Feature::fp may be supported on current CPU,
+        // but no way to detect it by OS API.
+        // Also, we require unsafe block for the extern "system" calls.
+        unsafe {
+            enable_feature(
+                Feature::asimd,
+                IsProcessorFeaturePresent(PF_ARM_NEON_INSTRUCTIONS_AVAILABLE) != FALSE,
+            );
+            enable_feature(
+                Feature::crc,
+                IsProcessorFeaturePresent(PF_ARM_V8_CRC32_INSTRUCTIONS_AVAILABLE) != FALSE,
+            );
+            // PF_ARM_V8_CRYPTO_INSTRUCTIONS_AVAILABLE means aes, sha1, sha2 and
+            // pmull support
+            enable_feature(
+                Feature::aes,
+                IsProcessorFeaturePresent(PF_ARM_V8_CRYPTO_INSTRUCTIONS_AVAILABLE) != FALSE,
+            );
+            enable_feature(
+                Feature::pmull,
+                IsProcessorFeaturePresent(PF_ARM_V8_CRYPTO_INSTRUCTIONS_AVAILABLE) != FALSE,
+            );
+            enable_feature(
+                Feature::sha2,
+                IsProcessorFeaturePresent(PF_ARM_V8_CRYPTO_INSTRUCTIONS_AVAILABLE) != FALSE,
+            );
+        }
+    }
+    value
+}