src/math/modfl.c

   1 #include "libm.h"
   2
   3 #if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
   4 long double modfl(long double x, long double *iptr)
   5 {
   6         double d;
   7         long double r;
   8
   9         r = modf(x, &d);
  10         *iptr = d;
  11         return r;
  12 }
  13 #elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
  14
  15 static const long double toint = 1/LDBL_EPSILON;
  16
  17 long double modfl(long double x, long double *iptr)
  18 {
  19         union ldshape u = {x};
  20         int e = (u.i.se & 0x7fff) - 0x3fff;
  21         int s = u.i.se >> 15;
  22         long double absx;
  23         long double y;
  24
  25         /* no fractional part */
  26         if (e >= LDBL_MANT_DIG-1) {
  27                 *iptr = x;
  28                 if (isnan(x))
  29                         return x;
  30                 return s ? -0.0 : 0.0;
  31         }
  32
  33         /* no integral part*/
  34         if (e < 0) {
  35                 *iptr = s ? -0.0 : 0.0;
  36                 return x;
  37         }
  38
  39         /* raises spurious inexact */
  40         absx = s ? -x : x;
  41         y = absx + toint - toint - absx;
  42         if (y == 0) {
  43                 *iptr = x;
  44                 return s ? -0.0 : 0.0;
  45         }
  46         if (y > 0)
  47                 y -= 1;
  48         if (s)
  49                 y = -y;
  50         *iptr = x + y;
  51         return -y;
  52 }
  53 #endif