xref: /original-bsd/sys/i386/include/param.h (revision a1c2194a)
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  * %sccs.include.redist.c%
9  *
10  *	@(#)param.h	5.8 (Berkeley) 06/28/91
11  */
12 
13 /*
14  * Machine dependent constants for Intel 386.
15  */
16 
17 #define MACHINE "i386"
18 
19 /*
20  * Round p (pointer or byte index) up to a correctly-aligned value
21  * for all data types (int, long, ...).   The result is u_int and
22  * must be cast to any desired pointer type.
23  */
24 #define	ALIGN(p)	(((u_int)(p) + (sizeof(int) - 1)) &~ (sizeof(int) - 1))
25 
26 #define	NBPG		4096		/* bytes/page */
27 #define	PGOFSET		(NBPG-1)	/* byte offset into page */
28 #define	PGSHIFT		12		/* LOG2(NBPG) */
29 #define	NPTEPG		(NBPG/(sizeof (struct pte)))
30 
31 #define NBPDR		(1024*NBPG)	/* bytes/page dir */
32 #define	PDROFSET	(NBPDR-1)	/* byte offset into page dir */
33 #define	PDRSHIFT	22		/* LOG2(NBPDR) */
34 
35 #define	KERNBASE	0xFE000000	/* start of kernel virtual */
36 #define	BTOPKERNBASE	((u_long)KERNBASE >> PGSHIFT)
37 
38 #define	DEV_BSIZE	512
39 #define	DEV_BSHIFT	9		/* log2(DEV_BSIZE) */
40 #define BLKDEV_IOSIZE	2048
41 #define	MAXPHYS		(64 * 1024)	/* max raw I/O transfer size */
42 
43 #define	CLSIZE		1
44 #define	CLSIZELOG2	0
45 
46 /* NOTE: SSIZE, SINCR and UPAGES must be multiples of CLSIZE */
47 #define	SSIZE	1		/* initial stack size/NBPG */
48 #define	SINCR	1		/* increment of stack/NBPG */
49 
50 #define	UPAGES	2		/* pages of u-area */
51 
52 /*
53  * Constants related to network buffer management.
54  * MCLBYTES must be no larger than CLBYTES (the software page size), and,
55  * on machines that exchange pages of input or output buffers with mbuf
56  * clusters (MAPPED_MBUFS), MCLBYTES must also be an integral multiple
57  * of the hardware page size.
58  */
59 #define	MSIZE		128		/* size of an mbuf */
60 #define	MCLBYTES	1024
61 #define	MCLSHIFT	10
62 #define	MCLOFSET	(MCLBYTES - 1)
63 #ifndef NMBCLUSTERS
64 #ifdef GATEWAY
65 #define	NMBCLUSTERS	512		/* map size, max cluster allocation */
66 #else
67 #define	NMBCLUSTERS	256		/* map size, max cluster allocation */
68 #endif
69 #endif
70 
71 /*
72  * Size of kernel malloc arena in CLBYTES-sized logical pages
73  */
74 #ifndef NKMEMCLUSTERS
75 #define	NKMEMCLUSTERS	(2048*1024/CLBYTES)
76 #endif
77 /*
78  * Some macros for units conversion
79  */
80 /* Core clicks (4096 bytes) to segments and vice versa */
81 #define	ctos(x)	(x)
82 #define	stoc(x)	(x)
83 
84 /* Core clicks (4096 bytes) to disk blocks */
85 #define	ctod(x)	((x)<<(PGSHIFT-DEV_BSHIFT))
86 #define	dtoc(x)	((x)>>(PGSHIFT-DEV_BSHIFT))
87 #define	dtob(x)	((x)<<DEV_BSHIFT)
88 
89 /* clicks to bytes */
90 #define	ctob(x)	((x)<<PGSHIFT)
91 
92 /* bytes to clicks */
93 #define	btoc(x)	(((unsigned)(x)+(NBPG-1))>>PGSHIFT)
94 
95 #define	btodb(bytes)	 		/* calculates (bytes / DEV_BSIZE) */ \
96 	((unsigned)(bytes) >> DEV_BSHIFT)
97 #define	dbtob(db)			/* calculates (db * DEV_BSIZE) */ \
98 	((unsigned)(db) << DEV_BSHIFT)
99 
100 /*
101  * Map a ``block device block'' to a file system block.
102  * This should be device dependent, and will be if we
103  * add an entry to cdevsw/bdevsw for that purpose.
104  * For now though just use DEV_BSIZE.
105  */
106 #define	bdbtofsb(bn)	((bn) / (BLKDEV_IOSIZE/DEV_BSIZE))
107 
108 /*
109  * Mach derived conversion macros
110  */
111 #define i386_round_pdr(x)	((((unsigned)(x)) + NBPDR - 1) & ~(NBPDR-1))
112 #define i386_trunc_pdr(x)	((unsigned)(x) & ~(NBPDR-1))
113 #define i386_round_page(x)	((((unsigned)(x)) + NBPG - 1) & ~(NBPG-1))
114 #define i386_trunc_page(x)	((unsigned)(x) & ~(NBPG-1))
115 #define i386_btod(x)		((unsigned)(x) >> PDRSHIFT)
116 #define i386_dtob(x)		((unsigned)(x) << PDRSHIFT)
117 #define i386_btop(x)		((unsigned)(x) >> PGSHIFT)
118 #define i386_ptob(x)		((unsigned)(x) << PGSHIFT)
119 
120 #ifdef KERNEL
121 #ifndef LOCORE
122 int	cpuspeed;
123 #endif
124 #define	DELAY(n)	{ register int N = cpuspeed * (n); while (--N > 0); }
125 
126 #else
127 #define	DELAY(n)	{ register int N = (n); while (--N > 0); }
128 #endif
129