src/math/roundl.c

   1 #include "libm.h"
   2
   3 #if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
   4 long double roundl(long double x)
   5 {
   6         return round(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 roundl(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)
  19                 return x;
  20         if (u.i.se >> 15)
  21                 x = -x;
  22         if (e < 0x3fff-1) {
  23                 FORCE_EVAL(x + toint);
  24                 return 0*u.f;
  25         }
  26         y = x + toint - toint - x;
  27         if (y > 0.5)
  28                 y = y + x - 1;
  29         else if (y <= -0.5)
  30                 y = y + x + 1;
  31         else
  32                 y = y + x;
  33         if (u.i.se >> 15)
  34                 y = -y;
  35         return y;
  36 }
  37 #endif