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/*
* Mach Operating System
* Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
* All Rights Reserved.
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie Mellon
* the rights to redistribute these changes.
*/
/*
* File: mach/vm_param.h
* Author: Avadis Tevanian, Jr., Michael Wayne Young
* Date: 1985
*
* Machine independent virtual memory parameters.
*
*/
#ifndef _MACH_VM_PARAM_H_
#define _MACH_VM_PARAM_H_
#include <mach/machine/vm_param.h>
#include <mach/machine/vm_types.h>
/*
* The machine independent pages are referred to as PAGES. A page
* is some number of hardware pages, depending on the target machine.
*
* All references to the size of a page should be done
* with PAGE_SIZE, PAGE_SHIFT, or PAGE_MASK.
* They may be implemented as either constants or variables,
* depending on more-specific code.
* If they're variables, they had better be initialized
* by the time system-independent code starts getting called.
*
* Regardless whether it is implemented with a constant or a variable,
* the PAGE_SIZE is assumed to be a power of two throughout the
* virtual memory system implementation.
*
* More-specific code must at least provide PAGE_SHIFT;
* we can calculate the others if necessary.
* (However, if PAGE_SHIFT really refers to a variable,
* PAGE_SIZE and PAGE_MASK should also be variables
* so their values don't have to be constantly recomputed.)
*/
#ifndef PAGE_SHIFT
#error mach/machine/vm_param.h needs to define PAGE_SHIFT.
#endif
#ifndef PAGE_SIZE
#define PAGE_SIZE (1 << PAGE_SHIFT)
#endif
#ifndef PAGE_MASK
#define PAGE_MASK (PAGE_SIZE-1)
#endif
/*
* Convert addresses to pages and vice versa.
* No rounding is used.
*/
#define atop(x) (((vm_size_t)(x)) >> PAGE_SHIFT)
#define ptoa(x) ((vm_offset_t)((x) << PAGE_SHIFT))
/*
* Round off or truncate to the nearest page. These will work
* for either addresses or counts. (i.e. 1 byte rounds to 1 page
* bytes.
*/
#define round_page(x) ((vm_offset_t)((((vm_offset_t)(x)) + PAGE_MASK) & ~PAGE_MASK))
#define trunc_page(x) ((vm_offset_t)(((vm_offset_t)(x)) & ~PAGE_MASK))
/*
* Determine whether an address is page-aligned, or a count is
* an exact page multiple.
*/
#define page_aligned(x) ((((vm_offset_t) (x)) & PAGE_MASK) == 0)
#endif /* _MACH_VM_PARAM_H_ */
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