diff --git a/c/blake3_dispatch.c b/c/blake3_dispatch.c
index af6c3da..c9abc13 100644
--- a/c/blake3_dispatch.c
+++ b/c/blake3_dispatch.c
@@ -4,9 +4,12 @@
 
 #include "blake3_impl.h"
 
-#if defined(IS_X86)
 #if defined(_MSC_VER)
 #include <Windows.h>
+#endif
+
+#if defined(IS_X86)
+#if defined(_MSC_VER)
 #include <intrin.h>
 #elif defined(__GNUC__)
 #include <immintrin.h>
diff --git a/c/blake3_impl.h b/c/blake3_impl.h
index beab5cf..98611c3 100644
--- a/c/blake3_impl.h
+++ b/c/blake3_impl.h
@@ -28,7 +28,7 @@ enum blake3_flags {
 #define INLINE static inline __attribute__((always_inline))
 #endif
 
-#if defined(__x86_64__) || defined(_M_X64) 
+#if (defined(__x86_64__) || defined(_M_X64)) && !defined(_M_ARM64EC)
 #define IS_X86
 #define IS_X86_64
 #endif
@@ -38,7 +38,7 @@ enum blake3_flags {
 #define IS_X86_32
 #endif
 
-#if defined(__aarch64__) || defined(_M_ARM64)
+#if defined(__aarch64__) || defined(_M_ARM64) || defined(_M_ARM64EC)
 #define IS_AARCH64
 #endif