xref: /netbsd-src/sys/arch/i386/include/byte_swap.h (revision 3b01aba77a7a698587faaae455bbfe740923c1f5)
1 /*	$NetBSD: byte_swap.h,v 1.3 2001/05/30 12:28:44 mrg 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_OPT)
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