src/math/nexttowardf.c

   1 #include "libm.h"
   2
   3 float nexttowardf(float x, long double y)
   4 {
   5         union {float f; uint32_t i;} ux = {x};
   6         uint32_t e;
   7
   8         if (isnan(x) || isnan(y))
   9                 return x + y;
  10         if (x == y)
  11                 return y;
  12         if (x == 0) {
  13                 ux.i = 1;
  14                 if (signbit(y))
  15                         ux.i |= 0x80000000;
  16         } else if (x < y) {
  17                 if (signbit(x))
  18                         ux.i--;
  19                 else
  20                         ux.i++;
  21         } else {
  22                 if (signbit(x))
  23                         ux.i++;
  24                 else
  25                         ux.i--;
  26         }
  27         e = ux.i & 0x7f800000;
  28         /* raise overflow if ux.f is infinite and x is finite */
  29         if (e == 0x7f800000)
  30                 FORCE_EVAL(x+x);
  31         /* raise underflow if ux.f is subnormal or zero */
  32         if (e == 0)
  33                 FORCE_EVAL(x*x + ux.f*ux.f);
  34         return ux.f;
  35 }