new file mode 100644
--- /dev/null
+++ b/packages/language/c/libm/current/src/double/portable-api/s_isnan.c
@@ -0,0 +1,84 @@
+//===========================================================================
+//
+//      s_isnan.c
+//
+//      Part of the standard mathematical function library
+//
+//===========================================================================
+//####COPYRIGHTBEGIN####
+//
+// -------------------------------------------
+// The contents of this file are subject to the Cygnus eCos Public License
+// Version 1.0 (the "License"); you may not use this file except in
+// compliance with the License.  You may obtain a copy of the License at
+// http://sourceware.cygnus.com/ecos
+// 
+// Software distributed under the License is distributed on an "AS IS"
+// basis, WITHOUT WARRANTY OF ANY KIND, either express or implied.  See the
+// License for the specific language governing rights and limitations under
+// the License.
+// 
+// The Original Code is eCos - Embedded Cygnus Operating System, released
+// September 30, 1998.
+// 
+// The Initial Developer of the Original Code is Cygnus.  Portions created
+// by Cygnus are Copyright (C) 1998 Cygnus Solutions.  All Rights Reserved.
+// -------------------------------------------
+//
+//####COPYRIGHTEND####
+//===========================================================================
+//#####DESCRIPTIONBEGIN####
+//
+// Author(s):   jlarmour@cygnus.co.uk
+// Contributors:  jlarmour@cygnus.co.uk
+// Date:        1998-02-13
+// Purpose:     
+// Description: 
+// Usage:       
+//
+//####DESCRIPTIONEND####
+//
+//===========================================================================
+
+// CONFIGURATION
+
+#include <pkgconf/libm.h>   // Configuration header
+
+// Include the Math library?
+#ifdef CYGPKG_LIBM     
+
+// Derived from code with the following copyright
+
+
+/* @(#)s_isnan.c 1.3 95/01/18 */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunSoft, 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 "mathincl/fdlibm.h"
+
+        int isnan(double x)
+{
+        int hx,lx;
+        hx = (CYG_LIBM_HI(x)&0x7fffffff);
+        lx = CYG_LIBM_LO(x);
+        hx |= (unsigned)(lx|(-lx))>>31; 
+        hx = 0x7ff00000 - hx;
+        return ((unsigned)(hx))>>31;
+}
+
+#endif // ifdef CYGPKG_LIBM     
+
+// EOF s_isnan.c