[apple/xnu.git] / libkern / libkern / OSCrossEndian.h

/*
 * Copyright (c) 2000-2005 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code 
 * as defined in and that are subject to the Apple Public Source License 
 * Version 2.0 (the 'License'). You may not use this file except in 
 * compliance with the License.  The rights granted to you under the 
 * License may not be used to create, or enable the creation or 
 * redistribution of, unlawful or unlicensed copies of an Apple operating 
 * system, or to circumvent, violate, or enable the circumvention or 
 * violation of, any terms of an Apple operating system software license 
 * agreement.
 *
 * Please obtain a copy of the License at 
 * http://www.opensource.apple.com/apsl/ and read it before using this 
 * file.
 *
 * The Original Code and all software distributed under the License are 
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 
 * Please see the License for the specific language governing rights and 
 * limitations under the License.
 *
 * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
 */

/*
 * This private header exports 3 APIs.
 *	_OSRosettaCheck() - 	An inline function that returns true if we are
 *				currently running under Rosetta.
 *	IF_ROSETTA() -		Which is used to as a regular conditional
 *				expression that is true only if the current
 *				code is executing in the Rosetta
 *				translation space.
 *	ROSETTA_ONLY(exprs) - 	Which is used to create a block code that only
 *				executes if we are running in Rosetta.
 *
 * for example
 *
 * IF_ROSETTA() {
 *	// Do Cross endian swapping of input data
 *	outdata = OSSwap??(indata);
 * }
 * else {
 * 	// Do straight through 
 *	outdata = indata;
 * }
 *
 * outdata = indata;
 * ROSETTA_ONLY(
 *	// Do Cross endian swapping of input data
 *	outdata = OSSwap??(outdata);
 * );
 */

#ifndef _LIBKERN_OSCROSSENDIAN_H
#define _LIBKERN_OSCROSSENDIAN_H

#if __ppc__

static __inline__ int _OSRosettaCheck(void)
{
    int isCrossEndian;

    __asm__ (  "b 0f\n"
	    "	.long 0x14400004\n"
	    "	li %0,1\n"
	    "0:"
	: "=r" (isCrossEndian) : "0" (0)
    );

    return isCrossEndian;
}

#else

static __inline__ int _OSRosettaCheck(void) { return 0; }

#endif

#define IF_ROSETTA() if (__builtin_expect(_OSRosettaCheck(), 0) )

#define ROSETTA_ONLY(exprs)	\
do {				\
    IF_ROSETTA() {		\
	exprs			\
    }				\
} while(0)

#endif /*  _LIBKERN_OSCROSSENDIAN_H */
Commit	Line	Data
3a60a9f5	1	/*
8ad349bb	2	* Copyright (c) 2000-2005 Apple Computer, Inc. All rights reserved.
3a60a9f5	3	*
8ad349bb	4	* @APPLE_LICENSE_OSREFERENCE_HEADER_START@
3a60a9f5	5	*
8ad349bb A	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
	10	* License may not be used to create, or enable the creation or
	11	* redistribution of, unlawful or unlicensed copies of an Apple operating
	12	* system, or to circumvent, violate, or enable the circumvention or
	13	* violation of, any terms of an Apple operating system software license
	14	* agreement.
	15	*
	16	* Please obtain a copy of the License at
	17	* http://www.opensource.apple.com/apsl/ and read it before using this
	18	* file.
	19	*
	20	* The Original Code and all software distributed under the License are
	21	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	22	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	23	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	24	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	25	* Please see the License for the specific language governing rights and
	26	* limitations under the License.
	27	*
	28	* @APPLE_LICENSE_OSREFERENCE_HEADER_END@
3a60a9f5 A	29	*/
	30
	31	/*
	32	* This private header exports 3 APIs.
	33	* _OSRosettaCheck() - An inline function that returns true if we are
	34	* currently running under Rosetta.
	35	* IF_ROSETTA() - Which is used to as a regular conditional
	36	* expression that is true only if the current
	37	* code is executing in the Rosetta
	38	* translation space.
	39	* ROSETTA_ONLY(exprs) - Which is used to create a block code that only
	40	* executes if we are running in Rosetta.
	41	*
	42	* for example
	43	*
	44	* IF_ROSETTA() {
	45	* // Do Cross endian swapping of input data
	46	* outdata = OSSwap??(indata);
	47	* }
	48	* else {
	49	* // Do straight through
	50	* outdata = indata;
	51	* }
	52	*
	53	* outdata = indata;
	54	* ROSETTA_ONLY(
	55	* // Do Cross endian swapping of input data
	56	* outdata = OSSwap??(outdata);
	57	* );
	58	*/
	59
	60	#ifndef _LIBKERN_OSCROSSENDIAN_H
	61	#define _LIBKERN_OSCROSSENDIAN_H
	62
	63	#if __ppc__
	64
8ad349bb	65	static __inline__ int _OSRosettaCheck(void)
3a60a9f5	66	{
8ad349bb	67	int isCrossEndian;
3a60a9f5	68
8ad349bb A	69	__asm__ ( "b 0f\n"
	70	" .long 0x14400004\n"
	71	" li %0,1\n"
	72	"0:"
	73	: "=r" (isCrossEndian) : "0" (0)
	74	);
3a60a9f5	75
8ad349bb	76	return isCrossEndian;
3a60a9f5 A	77	}
3a60a9f5 A	78
8ad349bb	79	#else
3a60a9f5 A	80
	81	static __inline__ int _OSRosettaCheck(void) { return 0; }
	82
8ad349bb	83	#endif
3a60a9f5 A	84
	85	#define IF_ROSETTA() if (__builtin_expect(_OSRosettaCheck(), 0) )
	86
	87	#define ROSETTA_ONLY(exprs) \
	88	do { \
	89	IF_ROSETTA() { \
	90	exprs \
	91	} \
	92	} while(0)
	93
	94	#endif /* _LIBKERN_OSCROSSENDIAN_H */