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 2007 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25 
  26         .file   "byteorder.s"
  27 
  28 #include "SYS.h"
  29 
  30         /*
  31          * NOTE: htonl/ntohl are identical routines, as are htons/ntohs.
  32          * As such, they could be implemented as a single routine, using
  33          * multiple ALTENTRY/SET_SIZE definitions. We don't do this so
  34          * that they will have unique addresses, allowing DTrace and
  35          * other debuggers to tell them apart. 
  36          */
  37 
  38 
  39 /*
  40  *      unsigned long htonl( hl )
  41  *      unsigned long ntohl( hl )
  42  *      long hl;
  43  *      reverses the byte order of 'uint32_t hl'
  44  */
  45         ENTRY(htonl)
  46         movl    %edi, %eax      /* %eax = hl */
  47         bswap   %eax            /* reverses the byte order of %eax */
  48         ret                     /* return (%eax) */
  49         SET_SIZE(htonl)
  50 
  51         ENTRY(ntohl)
  52         movl    %edi, %eax      /* %eax = hl */
  53         bswap   %eax            /* reverses the byte order of %eax */
  54         ret                     /* return (%eax) */
  55         SET_SIZE(ntohl)
  56 
  57 /*
  58  *      unsigned short htons( hs )
  59  *      short hs;
  60  *
  61  *      reverses the byte order in hs.
  62  */
  63         ENTRY(htons)
  64         movl    %edi, %eax      /* %eax = hs */
  65         bswap   %eax            /* reverses the byte order of %eax */
  66         shrl    $16, %eax       /* moves high 16-bit to low 16-bit */
  67         ret                     /* return (%eax) */
  68         SET_SIZE(htons)
  69 
  70         ENTRY(ntohs)
  71         movl    %edi, %eax      /* %eax = hs */
  72         bswap   %eax            /* reverses the byte order of %eax */
  73         shrl    $16, %eax       /* moves high 16-bit to low 16-bit */
  74         ret                     /* return (%eax) */
  75         SET_SIZE(ntohs)