--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libquadmath/math/fdimq.c	Sun Aug 21 07:07:55 2011 +0900
@@ -0,0 +1,43 @@
+/* Return positive difference between arguments.
+   Copyright (C) 1997, 2004, 2009 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <errno.h>
+#include "quadmath-imp.h"
+
+__float128
+fdimq (__float128 x, __float128 y)
+{
+  int clsx = fpclassifyq (x);
+  int clsy = fpclassifyq (y);
+
+  if (clsx == QUADFP_NAN || clsy == QUADFP_NAN
+      || (y < 0 && clsx == QUADFP_INFINITE && clsy == QUADFP_INFINITE))
+    /* Raise invalid flag.  */
+    return x - y;
+
+  if (x <= y)
+    return 0.0Q;
+
+  __float128 r = x - y;
+  if (isinfq (r))
+    errno = ERANGE;
+
+  return r;
+}