reactos/lib/crtdll/old cruft/float/nextaf.c

   1 #define MAX_DOUBLE 1.7976931348623158e+308
   2 #define MIN_DOUBLE  2.2250738585072014e-308
   3
   4 double _xnextafter( double __x, double __y )
   5 {
   6         double_t *x = ( double_t *)&__x;
   7
   8         double __e;
   9         double_t *e = (double_t *)&__e;
  10
  11
  12         if ( _isnan(__x) || _isinf(__x) )
  13                 return __x;
  14
  15         if ( _isnan(__y) )
  16                 return __y;
  17
  18
  19         // don't go to infinity just by adding
  20
  21         if ( _isinf(__y) && fabs(__x) >= MAX_DOUBLE  )
  22                 return __x;
  23
  24         if ( !_isinf(__y) && fabs(__x - __y) <= MIN_DOUBLE  )
  25                 return __y;
  26
  27
  28
  29
  30         e->mantissal = 1;
  31         e->mantissah = 0;
  32         if ( x->exponent >= 53  )
  33                 e->exponent = x->exponent - 52;
  34         else
  35                 e->exponent = 1;
  36
  37         if ( fabs(__x) < fabs(__y) )
  38                 e->sign = 0;
  39         else
  40                 e->sign = 1;
  41
  42
  43
  44     return __x+__e;
  45
  46
  47
  48 }