math/w_tgammal_compat.c

   1 /* w_gammal.c -- long double version of w_gamma.c.
   2  * Conversion to long double by Ulrich Drepper,
   3  * Cygnus Support, drepper@cygnus.com.
   4  */
   5
   6 /*
   7  * ====================================================
   8  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   9  *
  10  * Developed at SunPro, a Sun Microsystems, Inc. business.
  11  * Permission to use, copy, modify, and distribute this
  12  * software is freely granted, provided that this notice
  13  * is preserved.
  14  * ====================================================
  15  */
  16
  17 /* long double gammal(double x)
  18  * Return the Gamma function of x.
  19  */
  20
  21 #include <errno.h>
  22 #include <math.h>
  23 #include <math_private.h>
  24 #include <math-svid-compat.h>
  25 #include <libm-alias-ldouble.h>
  26
  27 #if LIBM_SVID_COMPAT
  28 long double
  29 __tgammal(long double x)
  30 {
  31         int local_signgam;
  32         long double y = __ieee754_gammal_r(x,&local_signgam);
  33
  34         if(__glibc_unlikely (!isfinite (y) || y == 0)
  35            && (isfinite (x) || (isinf (x) && x < 0.0))
  36            && _LIB_VERSION != _IEEE_) {
  37           if(x==0.0)
  38             return __kernel_standard_l(x,x,250); /* tgamma pole */
  39           else if(__floorl(x)==x&&x<0.0L)
  40             return __kernel_standard_l(x,x,241); /* tgamma domain */
  41           else if (y == 0)
  42             __set_errno (ERANGE); /* tgamma underflow */
  43           else
  44             return __kernel_standard_l(x,x,240); /* tgamma overflow */
  45         }
  46         return local_signgam < 0 ? - y : y;
  47 }
  48 libm_alias_ldouble (__tgamma, tgamma)
  49 #endif