diff --git a/include/boost/functional/detail/float_functions.hpp b/include/boost/functional/detail/float_functions.hpp
index 9de3186..3b6ee85 100644
--- a/include/boost/functional/detail/float_functions.hpp
+++ b/include/boost/functional/detail/float_functions.hpp
@@ -6,6 +6,8 @@
 #if !defined(BOOST_FUNCTIONAL_DETAIL_FLOAT_FUNCTIONS_HPP)
 #define BOOST_FUNCTIONAL_DETAIL_FLOAT_FUNCTIONS_HPP
 
+#include <cmath>
+
 #if defined(_MSC_VER) && (_MSC_VER >= 1020)
 # pragma once
 #endif
diff --git a/include/boost/functional/detail/hash_float.hpp b/include/boost/functional/detail/hash_float.hpp
new file mode 100644
index 0000000..56e1464
--- /dev/null
+++ b/include/boost/functional/detail/hash_float.hpp
@@ -0,0 +1,54 @@
+
+//  (C) Copyright Daniel James 2005.
+//  Use, modification and distribution are subject to the
+//  Boost Software License, Version 1.0. (See accompanying file
+//  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+//  Based on Peter Dimov's proposal
+//  http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2005/n1756.pdf
+//  issue 6.18. 
+
+#if !defined(BOOST_FUNCTIONAL_DETAIL_HASH_FLOAT_HEADER)
+#define BOOST_FUNCTIONAL_DETAIL_HASH_FLOAT_HEADER
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1020)
+# pragma once
+#endif
+
+#include <boost/functional/detail/float_functions.hpp>
+
+namespace boost
+{
+    namespace hash_detail
+    {
+        template <class T>
+        inline std::size_t float_hash_value(T v)
+        {
+            int exp = 0;
+            errno = 0;
+            v = boost::hash_detail::call_frexp(v, &exp);
+            if(errno) return 0;
+
+            std::size_t seed = 0;
+
+            std::size_t const length
+                = (std::numeric_limits<T>::digits +
+                        std::numeric_limits<int>::digits - 1)
+                / std::numeric_limits<int>::digits;
+
+            for(std::size_t i = 0; i < length; ++i)
+            {
+                v = boost::hash_detail::call_ldexp(v, std::numeric_limits<int>::digits);
+                int const part = static_cast<int>(v);
+                v -= part;
+                boost::hash_combine(seed, part);
+            }
+
+            boost::hash_combine(seed, exp);
+
+            return seed;
+        }
+    }
+}
+
+#endif
diff --git a/include/boost/functional/hash/hash.hpp b/include/boost/functional/hash/hash.hpp
index 9103095..621da84 100644
--- a/include/boost/functional/hash/hash.hpp
+++ b/include/boost/functional/hash/hash.hpp
@@ -16,11 +16,10 @@
 #endif
 
 #include <boost/functional/hash_fwd.hpp>
-#include <cmath>
 #include <functional>
 #include <errno.h>
 #include <boost/limits.hpp>
-#include <boost/functional/detail/float_functions.hpp>
+#include <boost/functional/detail/hash_float.hpp>
 #include <boost/functional/detail/container_fwd.hpp>
 
 #if defined(BOOST_NO_FUNCTION_TEMPLATE_ORDERING)
@@ -244,37 +243,6 @@ namespace boost
         return hash_range(v.begin(), v.end());
     }
 
-    namespace hash_detail
-    {
-        template <class T>
-        inline std::size_t float_hash_value(T v)
-        {
-            int exp = 0;
-            errno = 0;
-            v = boost::hash_detail::call_frexp(v, &exp);
-            if(errno) return 0;
-
-            std::size_t seed = 0;
-
-            std::size_t const length
-                = (std::numeric_limits<T>::digits +
-                        std::numeric_limits<int>::digits - 1)
-                / std::numeric_limits<int>::digits;
-
-            for(std::size_t i = 0; i < length; ++i)
-            {
-                v = boost::hash_detail::call_ldexp(v, std::numeric_limits<int>::digits);
-                int const part = static_cast<int>(v);
-                v -= part;
-                boost::hash_combine(seed, part);
-            }
-
-            boost::hash_combine(seed, exp);
-
-            return seed;
-        }
-    }
-
     inline std::size_t hash_value(float v)
     {
         return boost::hash_detail::float_hash_value(v);