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byte_swap.h revision 1.1.8.1 
      1 /*	$NetBSD: byte_swap.h,v 1.1.8.1 2000/11/20 20:09:26 bouyer Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1998 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Charles M. Hannum.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *        This product includes software developed by the NetBSD
     21  *        Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 
     39 #ifndef _I386_BYTE_SWAP_H_
     40 #define	_I386_BYTE_SWAP_H_
     41 
     42 #if defined(_KERNEL) && !defined(_LKM)
     43 #include "opt_cputype.h"
     44 #endif
     45 
     46 #if defined(_KERNEL) && !defined(_LKM) && !defined(I386_CPU)
     47 #define	__byte_swap_long_variable(x) __extension__ \
     48 ({ register in_addr_t __x = (x); \
     49    __asm ("bswap %1" \
     50 	: "=r" (__x) \
     51 	: "0" (__x)); \
     52    __x; })
     53 #else
     54 #define	__byte_swap_long_variable(x) __extension__ \
     55 ({ register in_addr_t __x = (x); \
     56    __asm ("rorw $8, %w1\n\trorl $16, %1\n\trorw $8, %w1" \
     57 	: "=r" (__x) \
     58 	: "0" (__x)); \
     59    __x; })
     60 #endif	/* _KERNEL && ... */
     61 
     62 #define	__byte_swap_word_variable(x) __extension__ \
     63 ({ register in_port_t __x = (x); \
     64    __asm ("rorw $8, %w1" \
     65 	: "=r" (__x) \
     66 	: "0" (__x)); \
     67    __x; })
     68 
     69 #ifdef __OPTIMIZE__
     70 
     71 #define	__byte_swap_long_constant(x) \
     72 	((((x) & 0xff000000) >> 24) | \
     73 	 (((x) & 0x00ff0000) >>  8) | \
     74 	 (((x) & 0x0000ff00) <<  8) | \
     75 	 (((x) & 0x000000ff) << 24))
     76 #define	__byte_swap_word_constant(x) \
     77 	((((x) & 0xff00) >> 8) | \
     78 	 (((x) & 0x00ff) << 8))
     79 #define	__byte_swap_long(x) \
     80 	(__builtin_constant_p((x)) ? \
     81 	 __byte_swap_long_constant(x) : __byte_swap_long_variable(x))
     82 #define	__byte_swap_word(x) \
     83 	(__builtin_constant_p((x)) ? \
     84 	 __byte_swap_word_constant(x) : __byte_swap_word_variable(x))
     85 
     86 #else /* __OPTIMIZE__ */
     87 
     88 #define	__byte_swap_long(x)	__byte_swap_long_variable(x)
     89 #define	__byte_swap_word(x)	__byte_swap_word_variable(x)
     90 
     91 #endif /* __OPTIMIZE__ */
     92 
     93 #endif /* !_I386_BYTE_SWAP_H_ */
     94