usr/src/lib/libc/amd64/fp/_xtoull.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 2004 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26         .file   "_xtoull.s"
  27
  28 #include <SYS.h>
  29
  30         .set    cw,0
  31         .set    cw_old,2
  32         .text
  33         .align  16
  34 two_to_63: .4byte       0x5f000000
  35
  36         ENTRY(__xtoull) /* 387-stack to unsigned long long */
  37         subq    $16,%rsp
  38         fstcw   cw_old(%rsp)
  39         movw    cw_old(%rsp),%ax
  40         movw    %ax,%cx
  41         andw    $0x0c00,%cx             /* save RC */
  42         orw     $0x0c00,%ax
  43         movw    %ax,cw(%rsp)
  44         fldcw   cw(%rsp)
  45         flds    two_to_63(%rip)
  46         fcomip  %st(1),%st              /* compare 2**63 to x */
  47         jp      .donotsub               /* jump if x is NaN */
  48         ja      .donotsub               /* jump if 2**63 > x */
  49         fsubs   two_to_63(%rip)         /* subtract 2**63 */
  50 .donotsub:
  51         fistpll 8(%rsp)
  52         fwait                           /* in case fistpll causes exception */
  53         movq    8(%rsp),%rax
  54         jp      .donotadd
  55         ja      .donotadd               /* flags did not change */
  56         movq    $0x8000000000000000,%rcx
  57         addq    %rcx,%rax               /* add back 2**63 */
  58 .donotadd:
  59         fstcw   cw(%rsp)                /* fetch CW in case masks changed */
  60         movw    cw(%rsp),%dx
  61         andw    $0xf3ff,%dx
  62         orw     %cx,%dx                 /* restore RC */
  63         movw    %dx,cw(%rsp)
  64         fldcw   cw(%rsp)
  65         addq    $16,%rsp
  66         ret
  67         SET_SIZE(__xtoull)