Source to osfmk/mach/vm_param.h

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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
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 * thereof, and that both notices appear in supporting documentation.
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 */
/*
 */
/*
 *	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_

#ifndef	KERNEL_PRIVATE

#error YOU HAVE MADE A MISTAKE BY INCLUDING THIS FILE;
#error
#error THIS FILE SHOULD NOT BE VISIBLE TO USER PROGRAMS.
#error
#error USE <mach/machine/vm_param.h> TO GET MACHINE-DEPENDENT ADDRESS
#error SPACE AND PAGE SIZE ITEMS.
#error
#error USE <mach/machine/vm_types.h> TO GET TYPE DECLARATIONS USED IN
#error THE MACH KERNEL INTERFACE.
#error
#error IN ALL PROBABILITY, YOU SHOULD GET ALL OF THE TYPES USED IN THE
#error INTERFACE FROM <mach/mach_types.h>

#endif	/* KERNEL_PRIVATE */

#include <mach/machine/vm_param.h>
#include <mach/machine/vm_types.h>

/*
 *	The machine independent pages are refered 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
 *	or PAGE_SHIFT.  The fact they are variables is hidden here so that
 *	we can easily make them constant if we so desire.
 */

/*
 *	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.
 */

#ifndef	PAGE_SIZE_FIXED
extern vm_size_t	page_size;
extern vm_size_t	page_mask;
extern int		page_shift;

#define PAGE_SIZE	page_size	/* size of page in addressible units */
#define PAGE_SHIFT	page_shift	/* number of bits to shift for pages */
#define PAGE_MASK	page_mask	/* mask for offset within page */
#else	/* PAGE_SIZE_FIXED */
#define PAGE_SIZE	4096
#define PAGE_SHIFT	12
#define	PAGE_MASK	(PAGE_SIZE-1)
#endif	/* PAGE_SIZE_FIXED */

#ifndef	ASSEMBLER
/*
 *	Convert addresses to pages and vice versa.
 *	No rounding is used.
 */

#define atop(x)		(((natural_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)

extern vm_size_t	mem_size;	/* size of physical memory (bytes) */

#endif	/* ASSEMBLER */
#endif	/* _MACH_VM_PARAM_H_ */