gen.subproj/i386.subproj/isinf.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * Copyright (c) 1987 NeXT, INC.
  24  */
  25
  26 /*
  27  * isinf -- returns 1 if positive IEEE infinity, -1 if negative
  28  *          IEEE infinity, 0 otherwise.
  29  */
  30 int
  31 isinf(d)
  32 double d;
  33 {
  34         int i;
  35
  36         i = *((int *)&d + 1);
  37         if (i == 0x7ff00000)
  38                 return(1);
  39         if (i == 0xfff00000)
  40                 return(-1);
  41         return(0);
  42 }