tanhl.c raw

   1  #include "libm.h"
   2  
   3  #if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
   4  long double tanhl(long double x)
   5  {
   6  	return tanh(x);
   7  }
   8  #elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384
   9  long double tanhl(long double x)
  10  {
  11  	union ldshape u = {x};
  12  	unsigned ex = u.i.se & 0x7fff;
  13  	unsigned sign = u.i.se & 0x8000;
  14  	uint32_t w;
  15  	long double t;
  16  
  17  	/* x = |x| */
  18  	u.i.se = ex;
  19  	x = u.f;
  20  	w = u.i.m >> 32;
  21  
  22  	if (ex > 0x3ffe || (ex == 0x3ffe && w > 0x8c9f53d5)) {
  23  		/* |x| > log(3)/2 ~= 0.5493 or nan */
  24  		if (ex >= 0x3fff+5) {
  25  			/* |x| >= 32 */
  26  			t = 1 + 0/(x + 0x1p-120f);
  27  		} else {
  28  			t = expm1l(2*x);
  29  			t = 1 - 2/(t+2);
  30  		}
  31  	} else if (ex > 0x3ffd || (ex == 0x3ffd && w > 0x82c577d4)) {
  32  		/* |x| > log(5/3)/2 ~= 0.2554 */
  33  		t = expm1l(2*x);
  34  		t = t/(t+2);
  35  	} else {
  36  		/* |x| is small */
  37  		t = expm1l(-2*x);
  38  		t = -t/(t+2);
  39  	}
  40  	return sign ? -t : t;
  41  }
  42  #elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384
  43  // TODO: broken implementation to make things compile
  44  long double tanhl(long double x)
  45  {
  46  	return tanh(x);
  47  }
  48  #endif
  49