src/math/ceill.c

   1 #include "libm.h"
   2
   3 #if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
   4 long double ceill(long double x)
   5 {
   6         return ceil(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 ceill(long double x)
  13 {
  14         union ldshape u = {x};
  15         int e = u.i.se & 0x7fff;
  16         long double y;
  17
  18         if (e >= 0x3fff+LDBL_MANT_DIG-1 || x == 0)
  19                 return x;
  20         /* y = int(x) - x, where int(x) is an integer neighbor of x */
  21         if (u.i.se >> 15)
  22                 y = x - toint + toint - x;
  23         else
  24                 y = x + toint - toint - x;
  25         /* special case because of non-nearest rounding modes */
  26         if (e <= 0x3fff-1) {
  27                 FORCE_EVAL(y);
  28                 return u.i.se >> 15 ? -0.0 : 1;
  29         }
  30         if (y < 0)
  31                 return x + y + 1;
  32         return x + y;
  33 }
  34 #endif