diff --git a/include/boost/detail/endian.hpp b/include/boost/detail/endian.hpp
index 3d85740..524435d 100644
--- a/include/boost/detail/endian.hpp
+++ b/include/boost/detail/endian.hpp
@@ -37,6 +37,12 @@
 #  error Unknown machine endianness detected.
 # endif
 # define BOOST_BYTE_ORDER __BYTE_ORDER
+#elif defined(_BIG_ENDIAN)
+# define BOOST_BIG_ENDIAN
+# define BOOST_BYTE_ORDER 4321
+#elif defined(_LITTLE_ENDIAN)
+# define BOOST_LITTLE_ENDIAN
+# define BOOST_BYTE_ORDER 1234
 #elif defined(__sparc) || defined(__sparc__) \
    || defined(_POWER) || defined(__powerpc__) \
    || defined(__ppc__) || defined(__hpux) \