diff --git a/include/mbedtls/bignum.h b/include/mbedtls/bignum.h
index 0b26727f3..2c5ace690 100644
--- a/include/mbedtls/bignum.h
+++ b/include/mbedtls/bignum.h
@@ -129,7 +129,8 @@
         defined(__ppc64__) || defined(__powerpc64__)  || \
         defined(__ia64__)  || defined(__alpha__)      || \
         ( defined(__sparc__) && defined(__arch64__) ) || \
-        defined(__s390x__) || defined(__mips64) )
+        defined(__s390x__) || defined(__mips64)       || \
+        defined(__aarch64__) )
         #if !defined(MBEDTLS_HAVE_INT64)
             #define MBEDTLS_HAVE_INT64
         #endif /* MBEDTLS_HAVE_INT64 */
diff --git a/include/mbedtls/bn_mul.h b/include/mbedtls/bn_mul.h
index f7cb07252..163869ae7 100644
--- a/include/mbedtls/bn_mul.h
+++ b/include/mbedtls/bn_mul.h
@@ -198,6 +198,30 @@
 
 #endif /* AMD64 */
 
+#if defined(__aarch64__)
+
+#define MULADDC_INIT                \
+    asm(
+
+#define MULADDC_CORE                \
+        "ldr x4, [%2], #8   \n\t"   \
+        "ldr x5, [%1]       \n\t"   \
+        "mul x6, x4, %3     \n\t"   \
+        "umulh x7, x4, %3   \n\t"   \
+        "adds x5, x5, x6    \n\t"   \
+        "adc x7, x7, xzr    \n\t"   \
+        "adds x5, x5, %0    \n\t"   \
+        "adc %0, x7, xzr    \n\t"   \
+        "str x5, [%1], #8   \n\t"
+
+#define MULADDC_STOP                        \
+         : "+r" (c),  "+r" (d), "+r" (s)    \
+         : "r" (b)                          \
+         : "x4", "x5", "x6", "x7", "cc"     \
+    );
+
+#endif /* Aarch64 */
+
 #if defined(__mc68020__) || defined(__mcpu32__)
 
 #define MULADDC_INIT                    \