diff --git a/ChangeLog b/ChangeLog
index 5b59ef79f..6905defb0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -24,6 +24,8 @@
      [sshd_config.5]
      oops, here too: put the MAC list into a display, like we do for
      ciphers, since groff has trouble with wide lines;
+ - (djm) [configure.ac umac.c] If platform doesn't provide swap32(3), then
+   fallback to provided bit-swizzing functions
 
 20070605
  - (dtucker) OpenBSD CVS Sync
@@ -2999,4 +3001,4 @@
    OpenServer 6 and add osr5bigcrypt support so when someone migrates
    passwords between UnixWare and OpenServer they will still work. OK dtucker@
 
-$Id: ChangeLog,v 1.4684 2007/06/11 04:07:12 djm Exp $
+$Id: ChangeLog,v 1.4685 2007/06/11 04:15:42 djm Exp $
diff --git a/configure.ac b/configure.ac
index 985ccb62d..143c164a9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,4 +1,4 @@
-# $Id: configure.ac,v 1.380 2007/05/09 22:57:43 tim Exp $
+# $Id: configure.ac,v 1.381 2007/06/11 04:15:43 djm Exp $
 #
 # Copyright (c) 1999-2004 Damien Miller
 #
@@ -15,7 +15,7 @@
 # OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
 AC_INIT(OpenSSH, Portable, openssh-unix-dev@mindrot.org)
-AC_REVISION($Revision: 1.380 $)
+AC_REVISION($Revision: 1.381 $)
 AC_CONFIG_SRCDIR([ssh.c])
 
 AC_CONFIG_HEADER(config.h)
@@ -1300,6 +1300,7 @@ AC_CHECK_FUNCS( \
 	strtonum \
 	strtoll \
 	strtoul \
+	swap32 \
 	sysconf \
 	tcgetpgrp \
 	truncate \
diff --git a/umac.c b/umac.c
index 676705c9c..29c202a21 100644
--- a/umac.c
+++ b/umac.c
@@ -122,7 +122,11 @@ typedef unsigned int	UWORD;  /* Register */
 /* --- Endian Conversion --- Forcing assembly on some platforms           */
 /* ---------------------------------------------------------------------- */
 
-#if 0
+#if HAVE_SWAP32
+#define LOAD_UINT32_REVERSED(p)		(swap32(*(UINT32 *)(p)))
+#define STORE_UINT32_REVERSED(p,v) 	(*(UINT32 *)(p) = swap32(v))
+#else /* HAVE_SWAP32 */
+
 static UINT32 LOAD_UINT32_REVERSED(void *ptr)
 {
     UINT32 temp = *(UINT32 *)ptr;
@@ -137,15 +141,12 @@ static void STORE_UINT32_REVERSED(void *ptr, UINT32 x)
     *(UINT32 *)ptr = (i >> 24) | ((i & 0x00FF0000) >> 8 )
                    | ((i & 0x0000FF00) << 8 ) | (i << 24);
 }
-#endif
+#endif /* HAVE_SWAP32 */
 
 /* The following definitions use the above reversal-primitives to do the right
  * thing on endian specific load and stores.
  */
 
-#define LOAD_UINT32_REVERSED(p)		(swap32(*(UINT32 *)(p)))
-#define STORE_UINT32_REVERSED(p,v) 	(*(UINT32 *)(p) = swap32(v))
-
 #if (__LITTLE_ENDIAN__)
 #define LOAD_UINT32_LITTLE(ptr)     (*(UINT32 *)(ptr))
 #define STORE_UINT32_BIG(ptr,x)     STORE_UINT32_REVERSED(ptr,x)
@@ -154,8 +155,6 @@ static void STORE_UINT32_REVERSED(void *ptr, UINT32 x)
 #define STORE_UINT32_BIG(ptr,x)     (*(UINT32 *)(ptr) = (UINT32)(x))
 #endif
 
-
-
 /* ---------------------------------------------------------------------- */
 /* ---------------------------------------------------------------------- */
 /* ----- Begin KDF & PDF Section ---------------------------------------- */