xref: /freebsd/sys/i386/include/param.h (revision e627b39baccd1ec9129690167cf5e6d860509655)
1 /*-
2  * Copyright (c) 1990 The Regents of the University of California.
3  * All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * William Jolitz.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *	This product includes software developed by the University of
19  *	California, Berkeley and its contributors.
20  * 4. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  *
36  *	from: @(#)param.h	5.8 (Berkeley) 6/28/91
37  *	$Id: param.h,v 1.21 1996/05/02 22:25:17 phk Exp $
38  */
39 
40 #ifndef _MACHINE_PARAM_H_
41 #define	_MACHINE_PARAM_H_
42 
43 /*
44  * Machine dependent constants for Intel 386.
45  */
46 
47 #define MACHINE		"i386"
48 #define MID_MACHINE	MID_I386
49 
50 /*
51  * Round p (pointer or byte index) up to a correctly-aligned value
52  * for all data types (int, long, ...).   The result is unsigned int
53  * and must be cast to any desired pointer type.
54  */
55 #define ALIGNBYTES	(sizeof(int) - 1)
56 #define ALIGN(p)	(((unsigned)(p) + ALIGNBYTES) & ~ALIGNBYTES)
57 
58 #define PAGE_SHIFT	12		/* LOG2(PAGE_SIZE) */
59 #define PAGE_SIZE	(1<<PAGE_SHIFT)	/* bytes/page */
60 #define PAGE_MASK	(PAGE_SIZE-1)
61 #define NPTEPG		(PAGE_SIZE/(sizeof (pt_entry_t)))
62 
63 #define NPDEPG		(PAGE_SIZE/(sizeof (pd_entry_t)))
64 #define PDRSHIFT	22		/* LOG2(NBPDR) */
65 #define NBPDR		(1<<PDRSHIFT)	/* bytes/page dir */
66 
67 #define DEV_BSHIFT	9		/* log2(DEV_BSIZE) */
68 #define DEV_BSIZE	(1<<DEV_BSHIFT)
69 
70 #define BLKDEV_IOSIZE	2048
71 #define MAXPHYS		(64 * 1024)	/* max raw I/O transfer size */
72 
73 #define UPAGES	2		/* pages of u-area */
74 
75 /*
76  * Constants related to network buffer management.
77  * MCLBYTES must be no larger than CLBYTES (the software page size), and,
78  * on machines that exchange pages of input or output buffers with mbuf
79  * clusters (MAPPED_MBUFS), MCLBYTES must also be an integral multiple
80  * of the hardware page size.
81  */
82 #ifndef	MSIZE
83 #define MSIZE		128		/* size of an mbuf */
84 #endif	/* MSIZE */
85 
86 #ifndef	MCLSHIFT
87 #define MCLSHIFT	11		/* convert bytes to m_buf clusters */
88 #endif	/* MCLSHIFT */
89 #define MCLBYTES	(1 << MCLSHIFT)	/* size of an m_buf cluster */
90 #define MCLOFSET	(MCLBYTES - 1)	/* offset within an m_buf cluster */
91 
92 /*
93  * Some macros for units conversion
94  */
95 
96 /* clicks to bytes */
97 #define ctob(x)	((x)<<PAGE_SHIFT)
98 
99 /* bytes to clicks */
100 #define btoc(x)	(((unsigned)(x)+PAGE_MASK)>>PAGE_SHIFT)
101 
102 /*
103  * This is messy and perhaps slow because `bytes' may be an off_t.  We
104  * have to shift an unsigned type to avoid sign extension and we don't
105  * want to widen `bytes' unnecessarily.  Assume that off_t is long long
106  * and daddr_t is unsigned long.
107  */
108 #define btodb(bytes)	 		/* calculates (bytes / DEV_BSIZE) */ \
109 	(sizeof (bytes) > sizeof(long) \
110 	 ? (unsigned long)((unsigned long long)(bytes) >> DEV_BSHIFT) \
111 	 : (unsigned long)((unsigned long)(bytes) >> DEV_BSHIFT))
112 #define dbtob(db)			/* calculates (db * DEV_BSIZE) */ \
113 	((unsigned long long)(db) << DEV_BSHIFT)
114 
115 /*
116  * Mach derived conversion macros
117  */
118 #define trunc_page(x)		((unsigned)(x) & ~PAGE_MASK)
119 #define round_page(x)		((((unsigned)(x)) + PAGE_MASK) & ~PAGE_MASK)
120 
121 #define atop(x)			((unsigned)(x) >> PAGE_SHIFT)
122 #define ptoa(x)			((unsigned)(x) << PAGE_SHIFT)
123 
124 #define i386_btop(x)		((unsigned)(x) >> PAGE_SHIFT)
125 #define i386_ptob(x)		((unsigned)(x) << PAGE_SHIFT)
126 
127 #endif /* !_MACHINE_PARAM_H_ */
128