usr/src/lib/libbc/libc/gen/common/sparc/isinf.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*
  23  * Copyright 1986 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 #pragma ident   "%Z%%M% %I%     %E% SMI"
  28
  29 /*
  30  * Recognize an infinity or a NaN when one is presented.
  31  * This is for keeping various IO routines out of trouble
  32  */
  33
  34
  35 int
  36 isinf( d0, d1 )
  37     unsigned d0,d1;
  38     /* a lie -- actually its a ``double'' */
  39 {
  40     if (d1 != 0 ) return 0; /* nope -- low-order must be all zeros */
  41     if (d0 != 0x7ff00000 && d0 != 0xfff00000) return 0; /* nope */
  42     return 1;
  43 }
  44
  45 int
  46 isnan( d0,d1 )
  47     unsigned d0,d1;
  48     /* a lie -- actually its a ``double'' */
  49 {
  50 #define EXPONENT 0x7ff00000
  51 #define SIGN     0x80000000
  52     if ((d0 & EXPONENT) != EXPONENT ) return 0; /* exponent wrong */
  53     if ((d0 & ~(EXPONENT|SIGN)) == 0 && d1 == 0 ) return 0; /* must have bits */
  54     return 1;
  55 }