/* $Copyright:	$
 * Copyright (c) 1984, 1985, 1986, 1987, 1988, 1989, 1990 
 * Sequent Computer Systems, Inc.   All rights reserved.
 *  
 * This software is furnished under a license and may be used
 * only in accordance with the terms of that license and with the
 * inclusion of the above copyright notice.   This software may not
 * be provided or otherwise made available to, or used by, any
 * other person.  No title to or ownership of the software is
 * hereby transferred.
 */

#ident	"$Header: map.h 1.6 89/08/07 $"

#ifndef	_SYS_MAP_H_

/*
 * map.h
 *	Resource Allocation Maps.
 */

/* $Log:	map.h,v $
 */

/*
 * Associated routines manage sub-allocation of an address space using
 * an array of segment descriptors.  The first element of this array
 * is a map structure, describing the arrays extent and the name
 * of the controlled object.  Each additional structure represents
 * a free segment of the address space.
 *
 * A call to rminit initializes a resource map and may also be used
 * to free some address space for the map.  Subsequent calls to rmalloc
 * and rmfree allocate and free space in the resource map.  If the resource
 * map becomes too fragmented to be described in the available space,
 * then some of the resource is discarded.  This may lead to critical
 * shortages, but is better than not checking (as the previous versions
 * of these routines did) or giving up and calling panic().  The routines
 * could use linked lists and call a memory allocator when they run
 * out of space, but that would not solve the out of space problem when
 * called at interrupt time.
 *
 * N.B.: The address 0 in the resource address space is not available
 * as it is used internally by the resource map routines.
 */
struct map {
	struct	mapent *m_limit;	/* address of last slot in map */
	char	*m_name;		/* name of resource */
/* we use m_name when the map overflows, in warning messages */
};
struct mapent
{
	int	m_size;		/* size of this segment of the map */
	int	m_addr;		/* resource-space addr of start of segment */
};

#ifdef	INKERNEL
extern	struct	map *swapmap;
extern	int	nswapmap;
extern	struct	map *uptmap;
#endif	/* INKERNEL */

#define	_SYS_MAP_H_
#endif	/* _SYS_MAP_H_ */
