Source to osfmk/i386/iopb.h

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
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 * The contents of this file constitute Original Code as defined in and
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/*
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/* 
 * Mach Operating System
 * Copyright (c) 1991,1990 Carnegie Mellon University
 * All Rights Reserved.
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 */

/*
 */

#ifndef	_I386_IOPB_H_
#define	_I386_IOPB_H_

#include <i386/tss.h>
#include <kern/queue.h>

/*
 * IO permission bitmap.
 *
 * Allows only IO ports 0 .. 0xffff: for ISA machines.
 */

#define	iopb_howmany(a,b)	(((a)+(b)-1)/(b))

#define	IOPB_MAX	0xffff		/* x86 allows ports 0..ffff */
#define	IOPB_BYTES	(iopb_howmany(IOPB_MAX+1,8))

typedef	unsigned char	isa_iopb[IOPB_BYTES];

/*
 * An IO permission map is a task segment with an IO permission bitmap.
 */

struct iopb_tss {
	struct i386_tss	tss;		/* task state segment */
	isa_iopb	bitmap;		/* bitmap of mapped IO ports */
	unsigned int	barrier;	/* bitmap barrier for CPU slop */
	queue_head_t	io_port_list;	/* list of mapped IO ports */
	int		iopb_desc[2];	/* descriptor for this TSS */
};

typedef	struct iopb_tss	*iopb_tss_t;

#endif	/* _I386_IOPB_H_ */