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glibc  2.9
Functions
e_gammal_r.c File Reference
#include <math.h>
#include <math_private.h>

Go to the source code of this file.

Functions

long double __ieee754_gammal_r (long double x, int *signgamp)

Function Documentation

long double __ieee754_gammal_r ( long double  x,
int signgamp 
)

Definition at line 26 of file e_gammal_r.c.

{
  /* 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.  */
  u_int32_t es, hx, lx;

  GET_LDOUBLE_WORDS (es, hx, lx, x);

  if (((es & 0x7fff) | hx | lx) == 0)
    {
      /* Return value for x == 0 is Inf with divide by zero exception.  */
      *signgamp = 0;
      return 1.0 / x;
    }
  if (es == 0xffffffff && ((hx & 0x7fffffff) | lx) == 0)
    {
      /* x == -Inf.  According to ISO this is NaN.  */
      *signgamp = 0;
      return x - x;
    }
  if ((es & 0x7fff) == 0x7fff && ((hx & 0x7fffffff) | lx) != 0)
    {
      /* NaN, return it.  */
      *signgamp = 0;
      return x;
    }
  if ((es & 0x8000) != 0 && x < 0xffffffff && __rintl (x) == x)
    {
      /* Return value for integer x < 0 is NaN with invalid exception.  */
      *signgamp = 0;
      return (x - x) / (x - x);
    }

  /* XXX FIXME.  */
  return __ieee754_expl (__ieee754_lgammal_r (x, signgamp));
}

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