From 3b863cf88f17e280562a8f787ea0e943aaf6d73d Mon Sep 17 00:00:00 2001
From: XMRig <support@xmrig.com>
Date: Sun, 15 Jun 2025 04:58:03 +0700
Subject: [PATCH] Fixed __umul128 for MSVC ARM64.

---
 src/base/tools/cryptonote/umul128.h | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/src/base/tools/cryptonote/umul128.h b/src/base/tools/cryptonote/umul128.h
index a6e77da6..b9916648 100644
--- a/src/base/tools/cryptonote/umul128.h
+++ b/src/base/tools/cryptonote/umul128.h
@@ -23,15 +23,22 @@
 
 #pragma once
 
-
 #include <cstdint>
 
-#ifdef XMRIG_64_BIT
-#   ifdef _MSC_VER
+#if defined(XMRIG_64_BIT)
+#   if defined(_MSC_VER)
 #       include <intrin.h>
-#       pragma intrinsic(_umul128)
-#       define __umul128 _umul128
-#   elif defined __GNUC__
+#       if defined(XMRIG_ARM)
+            #pragma intrinsic(__umulh)
+            static inline uint64_t __umul128(uint64_t a, uint64_t b, uint64_t *high) {
+                *high = __umulh(a, b);
+                return a * b;
+            }
+#       else
+#           pragma intrinsic(_umul128)
+#           define __umul128 _umul128
+#       endif
+#   elif defined(__GNUC__)
         static inline uint64_t _umul128(uint64_t a, uint64_t b, uint64_t* hi)
         {
             unsigned __int128 r = (unsigned __int128) a * (unsigned __int128) b;