winsup/cygwin/math/fdiml.c

   1 /**
   2  * This file has no copyright assigned and is placed in the Public Domain.
   3  * This file is part of the mingw-w64 runtime package.
   4  * No warranty is given; refer to the file DISCLAIMER.PD within this package.
   5  */
   6 #include <errno.h>
   7 #include <math.h>
   8
   9 long double
  10 fdiml (long double x, long double y)
  11 {
  12   int cx = fpclassify (x), cy = fpclassify (y);
  13   long double r;
  14
  15   if (cx == FP_NAN || cy == FP_NAN
  16       || (y < 0 && cx == FP_INFINITE && cy == FP_INFINITE))
  17     return x - y;  /* Take care invalid flag is raised.  */
  18   if (x <= y)
  19     return 0.0;
  20   r = x - y;
  21   if (fpclassify (r) == FP_INFINITE)
  22     errno = ERANGE;
  23   return r;
  24 }