text: /* Test for signaling NaN.
     Copyright (C) 2013-2017 Free Software Foundation, Inc.
     This file is part of the GNU C Library.
  
     The GNU C Library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Lesser General Public
     License as published by the Free Software Foundation; either
     version 2.1 of the License, or (at your option) any later version.
  
     The GNU C Library is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     Lesser General Public License for more details.
  
     You should have received a copy of the GNU Lesser General Public
     License along with the GNU C Library; if not, see
     <http://www.gnu.org/licenses/>.  */
  
  #include <math.h>
  #include <math_private.h>
  #include <nan-high-order-bit.h>
  
  int
  __issignalingf (float x)
  {
    u_int32_t xi;
    GET_FLOAT_WORD (xi, x);
  #if HIGH_ORDER_BIT_IS_SET_FOR_SNAN
    /* We only have to care about the high-order bit of x's significand, because
       having it set (sNaN) already makes the significand different from that
       used to designate infinity.  */
    return (xi & 0x7fc00000) == 0x7fc00000;
  #else
    /* To keep the following comparison simple, toggle the quiet/signaling bit,
       so that it is set for sNaNs.  This is inverse to IEEE 754-2008 (as well as
       common practice for IEEE 754-1985).  */
    xi ^= 0x00400000;
    /* We have to compare for greater (instead of greater or equal), because x's
       significand being all-zero designates infinity not NaN.  */
    return (xi & 0x7fffffff) > 0x7fc00000;
  #endif
  }
  libm_hidden_def (__issignalingf)
  