Enable compiling on Windows ARM64 (see GH PR 579)

Legrandin · May 14, 2023 · 7e9183b · 7e9183b
1 parent 09f0ac5
commit 7e9183b
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Showing 3 changed files with 13 additions and 4 deletions.
diff --git a/Changelog.rst b/Changelog.rst
@@ -7,6 +7,7 @@ Changelog
 New features
 ---------------
 * Added support for DER BOOLEAN encodings.
+* The library now compiles on Windows ARM64. Thanks to Niyas Sait.
 
   Resolved issues
 ---------------

diff --git a/src/multiply.h b/src/multiply.h
@@ -15,10 +15,18 @@
     oh = (uint64_t)(pr >> 64);  \
     } while (0)
 
-#elif defined(_MSC_VER) && defined(_WIN64)
+#elif defined(_MSC_VER) && (defined(_M_X64) || defined(__x86_64__))
 
-#include <windows.h>
-#define DP_MULT(a,b,ol,oh) do { ol = UnsignedMultiply128(a,b,&oh); } while (0)
+#include <intrin.h>
+#define DP_MULT(a,b,ol,oh) do { ol = _umul128(a,b,&oh); } while (0)
+
+#elif defined(_MSC_VER) && defined(_M_ARM64)
+
+#include <intrin.h>
+#define DP_MULT(a,b,ol,oh) do { \
+    ol = ((uint64_t)(a))*(b);   \
+    oh = __umulh(a, b);         \
+} while (0)
 
 #else
 

diff --git a/src/multiply_64.c b/src/multiply_64.c
@@ -38,7 +38,7 @@
 /**
  * Add a 64-bit value x to y/sum_mid/sum_hi
  */
-#if defined(_WIN64) && (_MSC_VER>=1900)
+#if defined(_MSC_VER) && (_MSC_VER>=1900) && (defined(_M_X64) || defined(__x86_64__))
 
 #include <intrin.h>
 #define ADD192(y, x) do {           \