xref: /xnu-11215.61.5/libkern/libkern/OSCrossEndian.h (revision 4f1223e81cd707a65cc109d0b8ad6653699da3c4)
1 /*
2  * Copyright (c) 2000-2006 Apple Computer, Inc. All rights reserved.
3  *
4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5  *
6  * This file contains Original Code and/or Modifications of Original Code
7  * as defined in and that are subject to the Apple Public Source License
8  * Version 2.0 (the 'License'). You may not use this file except in
9  * compliance with the License. The rights granted to you under the License
10  * may not be used to create, or enable the creation or redistribution of,
11  * unlawful or unlicensed copies of an Apple operating system, or to
12  * circumvent, violate, or enable the circumvention or violation of, any
13  * terms of an Apple operating system software license agreement.
14  *
15  * Please obtain a copy of the License at
16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
17  *
18  * The Original Code and all software distributed under the License are
19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23  * Please see the License for the specific language governing rights and
24  * limitations under the License.
25  *
26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27  */
28 
29 /*
30  * This private header exports 3 APIs.
31  *	_OSRosettaCheck() -     An inline function that returns true if we are
32  *				currently running under Rosetta.
33  *	IF_ROSETTA() -		Which is used to as a regular conditional
34  *				expression that is true only if the current
35  *				code is executing in the Rosetta
36  *				translation space.
37  *	ROSETTA_ONLY(exprs) -   Which is used to create a block code that only
38  *				executes if we are running in Rosetta.
39  *
40  * for example
41  *
42  * IF_ROSETTA() {
43  *	// Do Cross endian swapping of input data
44  *	outdata = OSSwap??(indata);
45  * }
46  * else {
47  *      // Do straight through
48  *	outdata = indata;
49  * }
50  *
51  * outdata = indata;
52  * ROSETTA_ONLY(
53  *	// Do Cross endian swapping of input data
54  *	outdata = OSSwap??(outdata);
55  * );
56  */
57 
58 #ifndef _LIBKERN_OSCROSSENDIAN_H
59 #define _LIBKERN_OSCROSSENDIAN_H
60 
61 #include <sys/sysctl.h>
62 
63 static __inline__ int
_OSRosettaCheck(void)64 _OSRosettaCheck(void)
65 {
66 	return 0;
67 }
68 
69 #define IF_ROSETTA() if (__builtin_expect(_OSRosettaCheck(), 0) )
70 
71 #define ROSETTA_ONLY(exprs)     \
72 do {                            \
73     IF_ROSETTA() {              \
74 	exprs                   \
75     }                           \
76 } while(0)
77 
78 #endif /*  _LIBKERN_OSCROSSENDIAN_H */
79