diff --git a/timidity/optcode.c b/timidity/optcode.c
index 89fb3fdc..28d0949f 100644
--- a/timidity/optcode.c
+++ b/timidity/optcode.c
@@ -32,7 +32,9 @@
 #include "common.h"
 
 const char *arch_string =
-#ifdef IX64CPU
+#ifdef ARM64CPU
+	"[ARM64]"
+#elif defined(IX64CPU)
 	#if USE_X64_EXT_INTRIN == 10
 		"[x64 AVX512]"
 	#elif USE_X64_EXT_INTRIN == 9
diff --git a/timidity/optcode.h b/timidity/optcode.h
index 98f4cafd..6deeb779 100644
--- a/timidity/optcode.h
+++ b/timidity/optcode.h
@@ -42,6 +42,10 @@
 #undef IX64CPU
 #endif
 
+#if defined(_M_ARM64) || defined(__aarch64__)
+#define ARM64CPU 1
+#endif
+
 /* optimizing mode */
 /* 0: none         */
 /* 1: x86 asm      */
diff --git a/timidity/sysdep.h b/timidity/sysdep.h
index cf570a9c..28853217 100644
--- a/timidity/sysdep.h
+++ b/timidity/sysdep.h
@@ -53,7 +53,7 @@
 #define ARMCPU 1
 #endif
 
-#if defined(__aarch64__)
+#if defined(_M_ARM64) || defined(__aarch64__)
 #undef  ARMCPU
 #define ARM64CPU 1
 #endif
@@ -269,7 +269,7 @@ typedef double LDBL_T;
 /* pointer size is not long in WIN64 and x86_64 */
 #if (defined(SIZEOF_POINTER) && SIZEOF_POINTER == 8) || \
     (defined(__SIZEOF_POINTER__) && __SIZEOF_POINTER__ == 8) || \
-    (defined(__W32__) && defined(_AMD64_))
+    defined(_WIN64)
 /* 64bit arch */
 typedef  int64   ptr_size_t;
 typedef uint64 u_ptr_size_t;