1 files changed, 23 insertions, 1 deletions

diff --git a/src/lib/libcrypto/bn/arch/i386/bn_arch.h b/src/lib/libcrypto/bn/arch/i386/bn_arch.h
index e2b4957efc..268c51e41a 100644
--- a/src/lib/libcrypto/bn/arch/i386/bn_arch.h
+++ b/src/lib/libcrypto/bn/arch/i386/bn_arch.h
@@ -1,4 +1,4 @@
-/*      $OpenBSD: bn_arch.h,v 1.7 2023/01/28 16:33:34 jsing Exp $ */
+/*      $OpenBSD: bn_arch.h,v 1.8 2023/01/31 05:53:49 jsing Exp $ */
 /*
  * Copyright (c) 2023 Joel Sing <jsing@openbsd.org>
  *
@@ -60,5 +60,27 @@ bn_div_rem_words_inline(BN_ULONG h, BN_ULONG l, BN_ULONG d, BN_ULONG *out_q,
 }
 #endif /* __GNUC__ */
 
+#if defined(__GNUC__)
+#define HAVE_BN_UMUL_HILO
+
+static inline void
+bn_umul_hilo(BN_ULONG a, BN_ULONG b, BN_ULONG *out_h, BN_ULONG *out_l)
+{
+        BN_ULONG h, l;
+
+        /*
+         * Unsigned multiplication of %eax, with the double word result being
+         * stored in %edx:%eax.
+         */
+        __asm__ ("mull %3"
+            : "=d"(h), "=a"(l)
+            : "a"(a), "rm"(b)
+            : "cc");
+
+        *out_h = h;
+        *out_l = l;
+}
+#endif /* __GNUC__ */
+
 #endif
 #endif