1 files changed, 47 insertions, 0 deletions
diff --git a/sysdeps/libm-ieee754/e_gamma_r.c b/sysdeps/libm-ieee754/e_gamma_r.c
new file mode 100644
index 0000000000..eb80809843
--- /dev/null
+++ b/sysdeps/libm-ieee754/e_gamma_r.c
@@ -0,0 +1,47 @@
+/* Implementation of gamma function according to ISO C.
+   Copyright (C) 1997 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 Library General Public License as
+   published by the Free Software Foundation; either version 2 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
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <math.h>
+#include <math_private.h>
+
+
+double
+__ieee754_gamma_r (double x, int *signgamp)
+{
+  /* 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.  */
+  int32_t hx;
+  u_int32_t lx;
+
+  EXTRACT_WORDS (hx, lx, x);
+
+  if ((hx & 0x7fffffff | lx) == 0)
+    /* Return value for x == 0 is NaN with invalid exception.  */
+    return x / x;
+  if (hx < 0 && (u_int32_t) hx < 0xfff00000 && __rint (x) == x)
+    {
+      /* Return value for integer x < 0 is NaN with invalid exception.  */
+      return (x - x) / (x - x);
+    }
+
+  /* XXX FIXME.  */
+  return __ieee754_exp (__ieee754_lgamma_r (x, signgamp));
+}