usr/src/lib/libm/i386/src/isnanf.s

   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 (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  23  */
  24 /*
  25  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  26  * Use is subject to license terms.
  27  */
  28
  29         .file "isnanf.s"
  30
  31 #include "libm.h"
  32 LIBM_ANSI_PRAGMA_WEAK(isnanf,function)
  33         .weak _isnanf
  34         .type _isnanf,@function
  35 _isnanf = __isnanf
  36
  37         ENTRY(isnanf)
  38         movl    4(%esp),%eax            / eax <-- x
  39         andl    $0x7fffffff,%eax        / eax <-- abs(x)
  40         subl    $0x7f800000,%eax        / ZF <-- 1      iff x is infinite
  41         jae     .nan_or_inf             / no jump iff arg. is finite
  42         movl    $0,%eax
  43         ret
  44 .nan_or_inf:
  45         jnz     .got_nan                / no jump if arg. infinite;
  46                                         / let nan waste time
  47         ret                             / %eax = 0 here
  48 .got_nan:
  49         movl    $1,%eax                 / %eax was 0, must be made 1 to
  50                                         / indicate TRUE
  51         ret
  52         .align  4
  53         SET_SIZE(isnanf)
  54