libm/s_fdim.c

   1 /* Copyright (C) 2002 by  Red Hat, Incorporated. All rights reserved.
   2  *
   3  * Permission to use, copy, modify, and distribute this software
   4  * is freely granted, provided that this notice is preserved.
   5  */
   6
   7 #include "math.h"
   8 #include "math_private.h"
   9 #include <errno.h>
  10
  11 double fdim(double x, double y)
  12 {
  13   int cx = __fpclassify(x); /* need both NAN and INF */
  14   int cy = __fpclassify(y); /* need both NAN and INF */
  15   if (cx == FP_NAN || cy == NAN)
  16     return x - y;
  17
  18   if (x <= y)
  19           return .0;
  20
  21   double z = x - y;
  22   if (isinf(z) && cx != FP_INFINITE && cy != FP_INFINITE)
  23           __set_errno(ERANGE);
  24
  25   return z;
  26 }
  27 libm_hidden_def(fdim)