truncl.c raw

   1  #include "libm.h"
   2  
   3  #if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
   4  long double truncl(long double x)
   5  {
   6  	return trunc(x);
   7  }
   8  #elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
   9  
  10  static const long double toint = 1/LDBL_EPSILON;
  11  
  12  long double truncl(long double x)
  13  {
  14  	union ldshape u = {x};
  15  	int e = u.i.se & 0x7fff;
  16  	int s = u.i.se >> 15;
  17  	long double y;
  18  
  19  	if (e >= 0x3fff+LDBL_MANT_DIG-1)
  20  		return x;
  21  	if (e <= 0x3fff-1) {
  22  		FORCE_EVAL(x + 0x1p120f);
  23  		return x*0;
  24  	}
  25  	/* y = int(|x|) - |x|, where int(|x|) is an integer neighbor of |x| */
  26  	if (s)
  27  		x = -x;
  28  	y = x + toint - toint - x;
  29  	if (y > 0)
  30  		y -= 1;
  31  	x += y;
  32  	return s ? -x : x;
  33  }
  34  #endif
  35