xnu-2782.1.97.tar.gz

[apple/xnu.git] / libsyscall / wrappers / mach_approximate_time.c

/*
 * Copyright (c) 2008 Apple Inc. All rights reserved.
 *
 * @APPLE_LICENSE_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. 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_HEADER_END@
 */
#include <sys/types.h>
#include <machine/cpu_capabilities.h>

extern uint64_t mach_absolute_time(void);

#if defined(__arm64__) || defined(__x86_64__)

uint64_t mach_approximate_time(void) {
	uint8_t supported = *((uint8_t *)_COMM_PAGE_APPROX_TIME_SUPPORTED);
        if (supported)
        {
            return *((uint64_t *)_COMM_PAGE_APPROX_TIME);
        }
	return mach_absolute_time();
}

#endif