libm/s_isnan.c

   1 /*
   2  * ====================================================
   3  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   4  *
   5  * Developed at SunPro, a Sun Microsystems, Inc. business.
   6  * Permission to use, copy, modify, and distribute this
   7  * software is freely granted, provided that this notice
   8  * is preserved.
   9  * ====================================================
  10  */
  11
  12 /*
  13  * isnan(x) returns 1 is x is nan, else 0;
  14  * no branching!
  15  */
  16
  17 #include "math.h"
  18 #include "math_private.h"
  19
  20 int __isnan(double x)
  21 {
  22         int32_t hx,lx;
  23         EXTRACT_WORDS(hx,lx,x);
  24         hx &= 0x7fffffff;
  25         hx |= (u_int32_t)(lx|(-lx))>>31;
  26         hx = 0x7ff00000 - hx;
  27         return (int)(((u_int32_t)hx)>>31);
  28 }
  29 weak_alias(__isnan, isnan)
  30 libm_hidden_def(__isnan)