usr/src/lib/libm/i386/src/isnanl.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 "isnanl.s"
  30
  31 #include "libm.h"
  32 LIBM_ANSI_PRAGMA_WEAK(isnanl,function)
  33
  34         ENTRY(isnanl)
  35         movl    12(%esp),%eax           / ax <-- sign bit and exp
  36         andl    $0x00007fff,%eax
  37         jz      .not_nan                / jump if exp is all 0
  38         xorl    $0x00007fff,%eax
  39         jz      .nan_or_inf             / jump if exp is all 1
  40         testl   $0x80000000,8(%esp)
  41         jz      .got_nan                / jump if leading bit is 0
  42         movl    $0,%eax
  43 .not_nan:
  44         ret
  45 .nan_or_inf:                            / note that %eax = 0 from before
  46         cmpl    $0x80000000,8(%esp)     / what is first half of significand?
  47         jnz     .got_nan                / jump if not equal to 0x80000000
  48         testl   $0xffffffff,4(%esp)     / is second half of significand 0?
  49         jnz     .got_nan                / jump if not equal to 0
  50         ret
  51 .got_nan:
  52         movl    $1,%eax
  53         ret
  54         .align  4
  55         SET_SIZE(isnanl)