sysdeps/x86/fpu/s_isnanl.c

   1 /* s_isnanl.c -- long double version for i387 of s_isnan.c.
   2  */
   3
   4 /*
   5  * ====================================================
   6  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   7  *
   8  * Developed at SunPro, a Sun Microsystems, Inc. business.
   9  * Permission to use, copy, modify, and distribute this
  10  * software is freely granted, provided that this notice
  11  * is preserved.
  12  * ====================================================
  13  */
  14
  15 #if defined(LIBM_SCCS) && !defined(lint)
  16 static char rcsid[] = "$NetBSD: $";
  17 #endif
  18
  19 /*
  20  * isnanl(x) returns 1 is x is nan, else 0;
  21  * no branching!
  22  */
  23
  24 #include <math.h>
  25 #include <math_private.h>
  26
  27 int __isnanl(long double x)
  28 {
  29         int32_t se,hx,lx,pn;
  30         GET_LDOUBLE_WORDS(se,hx,lx,x);
  31         se = (se & 0x7fff) << 1;
  32         /* Detect pseudo-normal numbers, i.e. exponent is non-zero and the top
  33            bit of the significand is not set.   */
  34         pn = (uint32_t)((~hx & 0x80000000) & (se|(-se)))>>31;
  35         /* Clear the significand bit when computing mantissa.  */
  36         lx |= hx & 0x7fffffff;
  37         se |= (uint32_t)(lx|(-lx))>>31;
  38         se = 0xfffe - se;
  39
  40         return (int)(((uint32_t)(se)) >> 16) | pn;
  41 }
  42 hidden_def (__isnanl)
  43 weak_alias (__isnanl, isnanl)