diff --git a/ChangeLog b/ChangeLog
index e56e139dfd..c28272c735 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2009-08-26  Ulrich Drepper  <drepper@redhat.com>
+
+	* sysdeps/ieee754/dbl-64/wordsize-64/s_isnan.c: New file.
+
 2009-08-25  Ulrich Drepper  <drepper@redhat.com>
 
 	* sysdeps/ieee754/dbl-64/wordsize-64/s_lround.c: Add llround aliases.
diff --git a/sysdeps/ieee754/dbl-64/wordsize-64/s_isnan.c b/sysdeps/ieee754/dbl-64/wordsize-64/s_isnan.c
new file mode 100644
index 0000000000..3b08c54dd4
--- /dev/null
+++ b/sysdeps/ieee754/dbl-64/wordsize-64/s_isnan.c
@@ -0,0 +1,39 @@
+/* @(#)s_isnan.c 5.1 93/09/24 */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
+/*
+ * isnan(x) returns 1 is x is nan, else 0;
+ * no branching!
+ */
+
+#include "math.h"
+#include "math_private.h"
+
+#ifdef __STDC__
+	int __isnan(double x)
+#else
+	int __isnan(x)
+	double x;
+#endif
+{
+	int64_t hx;
+	EXTRACT_WORDS64(hx,x);
+	hx &= UINT64_C(0x7fffffffffffffff);
+	hx = UINT64_C(0x7ff0000000000000) - hx;
+	return (int)(((uint64_t)hx)>>63);
+}
+hidden_def (__isnan)
+weak_alias (__isnan, isnan)
+#ifdef NO_LONG_DOUBLE
+strong_alias (__isnan, __isnanl)
+weak_alias (__isnan, isnanl)
+#endif