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+/* Implementation of gamma function according to ISO C.
+ Copyright (C) 1997, 1999, 2002, 2004 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997 and
+ Jakub Jelinek <jj@ultra.linux.cz, 1999.
+
+ 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 "quadmath-imp.h"
+
+
+__float128
+tgammaq (__float128 x)
+{
+ /* We don't have a real gamma implementation now. We'll use lgamma
+ and the exp function. But due to the required boundary
+ conditions we must check some values separately. */
+ int64_t hx;
+ uint64_t lx;
+
+ GET_FLT128_WORDS64 (hx, lx, x);
+
+ if (((hx & 0x7fffffffffffffffLL) | lx) == 0)
+ /* Return value for x == 0 is Inf with divide by zero exception. */
+ return 1.0 / x;
+
+ if (hx < 0 && (uint64_t) hx < 0xffff000000000000ULL && rintq (x) == x)
+ /* Return value for integer x < 0 is NaN with invalid exception. */
+ return (x - x) / (x - x);
+
+ if (hx == 0xffff000000000000ULL && lx == 0)
+ /* x == -Inf. According to ISO this is NaN. */
+ return x - x;
+
+ /* XXX FIXME. */
+ return expq (lgammaq (x));
+}