/*
 * Copyright (c) 2000-2006 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

#include <sys/sysctl.h>

#if __ppc__

static __inline__ int
_OSRosettaCheck(void)
{
	int isCrossEndian = 0;
	int val = 0;
	size_t size = sizeof val;

	if (sysctlbyname("sysctl.proc_native", &val, &size, NULL, 0) == -1)
		isCrossEndian = 0;
	else
		isCrossEndian = val ? 0 : 1;

	return isCrossEndian;
}

#else /* __ppc__ */

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

#endif /* __ppc__ */

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

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

#endif /*  _LIBKERN_OSCROSSENDIAN_H */
