aboutsummaryrefslogtreecommitdiff
path: root/sysdeps/ieee754/dbl-64/e_gamma_r.c
diff options
context:
space:
mode:
authorUlrich Drepper <drepper@redhat.com>1999-07-14 00:54:57 +0000
committerUlrich Drepper <drepper@redhat.com>1999-07-14 00:54:57 +0000
commitabfbdde177c3a7155070dda1b2cdc8292054cc26 (patch)
treee021306b596381fbf8311d2b7eb294e918ff17c8 /sysdeps/ieee754/dbl-64/e_gamma_r.c
parent86421aa57ecfd70963ae66848bd6a6dd3b8e0fe6 (diff)
downloadglibc-abfbdde177c3a7155070dda1b2cdc8292054cc26.zip
glibc-abfbdde177c3a7155070dda1b2cdc8292054cc26.tar.gz
glibc-abfbdde177c3a7155070dda1b2cdc8292054cc26.tar.bz2
Update.
Diffstat (limited to 'sysdeps/ieee754/dbl-64/e_gamma_r.c')
-rw-r--r--sysdeps/ieee754/dbl-64/e_gamma_r.c51
1 files changed, 51 insertions, 0 deletions
diff --git a/sysdeps/ieee754/dbl-64/e_gamma_r.c b/sysdeps/ieee754/dbl-64/e_gamma_r.c
new file mode 100644
index 0000000..bd802c2
--- /dev/null
+++ b/sysdeps/ieee754/dbl-64/e_gamma_r.c
@@ -0,0 +1,51 @@
+/* Implementation of gamma function according to ISO C.
+ Copyright (C) 1997, 1999 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. */
+ *signgamp = 0;
+ 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. */
+ *signgamp = 0;
+ return (x - x) / (x - x);
+ }
+
+ /* XXX FIXME. */
+ return __ieee754_exp (__ieee754_lgamma_r (x, signgamp));
+}