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glibc  2.9
Functions | Variables
e_coshl.c File Reference
#include "math.h"
#include "math_private.h"

Go to the source code of this file.

Functions

long double __ieee754_coshl (long double x)

Variables

static long double one = 1.0
static long double half = 0.5
static long double huge = 1.0e4900L
static long double ovf_thresh = 1.1357216553474703894801348310092223067821E4L

Function Documentation

long double __ieee754_coshl ( long double  x)

Definition at line 70 of file e_coshl.c.

{
  long double t, w;
  int32_t ex;
  ieee854_long_double_shape_type u;

  u.value = x;
  ex = u.parts32.w0 & 0x7fffffff;

  /* Absolute value of x.  */
  u.parts32.w0 = ex;

  /* x is INF or NaN */
  if (ex >= 0x7fff0000)
    return x * x;

  /* |x| in [0,0.5*ln2], return 1+expm1l(|x|)^2/(2*expl(|x|)) */
  if (ex < 0x3ffd62e4) /* 0.3465728759765625 */
    {
      t = __expm1l (u.value);
      w = one + t;
      if (ex < 0x3fb80000) /* |x| < 2^-116 */
       return w;            /* cosh(tiny) = 1 */

      return one + (t * t) / (w + w);
    }

  /* |x| in [0.5*ln2,40], return (exp(|x|)+1/exp(|x|)/2; */
  if (ex < 0x40044000)
    {
      t = __ieee754_expl (u.value);
      return half * t + half / t;
    }

  /* |x| in [22, ln(maxdouble)] return half*exp(|x|) */
  if (ex <= 0x400c62e3) /* 11356.375 */
    return half * __ieee754_expl (u.value);

  /* |x| in [log(maxdouble), overflowthresold] */
  if (u.value <= ovf_thresh)
    {
      w = __ieee754_expl (half * u.value);
      t = half * w;
      return t * w;
    }

  /* |x| > overflowthresold, cosh(x) overflow */
  return huge * huge;
}

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Variable Documentation

long double half = 0.5 [static]

Definition at line 61 of file e_coshl.c.

long double huge = 1.0e4900L [static]

Definition at line 61 of file e_coshl.c.

long double one = 1.0 [static]

Definition at line 61 of file e_coshl.c.

long double ovf_thresh = 1.1357216553474703894801348310092223067821E4L [static]

Definition at line 62 of file e_coshl.c.