sysdeps/ieee754/dbl-64/s_isnan.c

   1 /* @(#)s_isnan.c 5.1 93/09/24 */
   2 /*
   3  * ====================================================
   4  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   5  *
   6  * Developed at SunPro, a Sun Microsystems, Inc. business.
   7  * Permission to use, copy, modify, and distribute this
   8  * software is freely granted, provided that this notice
   9  * is preserved.
  10  * ====================================================
  11  */
  12
  13 /*
  14  * isnan(x) returns 1 is x is nan, else 0;
  15  * no branching!
  16  */
  17
  18 #include <math.h>
  19 #include <math_private.h>
  20 #include <ldbl-classify-compat.h>
  21 #include <shlib-compat.h>
  22 #include <stdint.h>
  23
  24 int
  25 __isnan (double x)
  26 {
  27   int64_t hx;
  28   EXTRACT_WORDS64 (hx, x);
  29   hx &= UINT64_C (0x7fffffffffffffff);
  30   hx = UINT64_C (0x7ff0000000000000) - hx;
  31   return (int)(((uint64_t)hx)>>63);
  32 }
  33 hidden_def (__isnan)
  34 weak_alias (__isnan, isnan)
  35 #ifdef NO_LONG_DOUBLE
  36 # if LDBL_CLASSIFY_COMPAT && SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_23)
  37 compat_symbol (libc, __isnan, __isnanl, GLIBC_2_0);
  38 # endif
  39 weak_alias (__isnan, isnanl)
  40 #endif