xref: /csrg-svn/sys/i386/include/param.h (revision 68632)

/*-
 * Copyright (c) 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * William Jolitz.
 *
 * %sccs.include.redist.c%
 *
 *	@(#)param.h	8.2 (Berkeley) 03/29/95
 */

/*
 * Machine dependent constants for Intel 386.
 */

#define MACHINE "i386"

/*
 * Round p (pointer or byte index) up to a correctly-aligned value for all
 * data types (int, long, ...).   The result is u_int and must be cast to
 * any desired pointer type.
 */
#define	ALIGNBYTES	3
#define	ALIGN(p)	(((u_int)(p) + ALIGNBYTES) &~ ALIGNBYTES)

#define	NBPG		4096		/* bytes/page */
#define	PGOFSET		(NBPG-1)	/* byte offset into page */
#define	PGSHIFT		12		/* LOG2(NBPG) */
#define	NPTEPG		(NBPG/(sizeof (struct pte)))

#define NBPDR		(1024*NBPG)	/* bytes/page dir */
#define	PDROFSET	(NBPDR-1)	/* byte offset into page dir */
#define	PDRSHIFT	22		/* LOG2(NBPDR) */

#define	KERNBASE	0xFE000000	/* start of kernel virtual */
#define	BTOPKERNBASE	((u_long)KERNBASE >> PGSHIFT)

#define	DEV_BSIZE	512
#define	DEV_BSHIFT	9		/* log2(DEV_BSIZE) */
#define BLKDEV_IOSIZE	2048
#define	MAXPHYS		(64 * 1024)	/* max raw I/O transfer size */

#define	CLSIZE		1
#define	CLSIZELOG2	0

/* NOTE: SSIZE, SINCR and UPAGES must be multiples of CLSIZE */
#define	SSIZE	1		/* initial stack size/NBPG */
#define	SINCR	1		/* increment of stack/NBPG */

#define	UPAGES	2		/* pages of u-area */

/*
 * Constants related to network buffer management.
 * MCLBYTES must be no larger than CLBYTES (the software page size), and,
 * on machines that exchange pages of input or output buffers with mbuf
 * clusters (MAPPED_MBUFS), MCLBYTES must also be an integral multiple
 * of the hardware page size.
 */
#define	MSIZE		128		/* size of an mbuf */
#define	MCLBYTES	1024
#define	MCLSHIFT	10
#define	MCLOFSET	(MCLBYTES - 1)
#ifndef NMBCLUSTERS
#ifdef GATEWAY
#define	NMBCLUSTERS	512		/* map size, max cluster allocation */
#else
#define	NMBCLUSTERS	256		/* map size, max cluster allocation */
#endif
#endif

/*
 * Size of kernel malloc arena in CLBYTES-sized logical pages
 */
#ifndef NKMEMCLUSTERS
#define	NKMEMCLUSTERS	(2048*1024/CLBYTES)
#endif
/*
 * Some macros for units conversion
 */
/* Core clicks (4096 bytes) to segments and vice versa */
#define	ctos(x)	(x)
#define	stoc(x)	(x)

/* Core clicks (4096 bytes) to disk blocks */
#define	ctod(x)	((x)<<(PGSHIFT-DEV_BSHIFT))
#define	dtoc(x)	((x)>>(PGSHIFT-DEV_BSHIFT))
#define	dtob(x)	((x)<<DEV_BSHIFT)

/* clicks to bytes */
#define	ctob(x)	((x)<<PGSHIFT)

/* bytes to clicks */
#define	btoc(x)	(((unsigned)(x)+(NBPG-1))>>PGSHIFT)

#define	btodb(bytes)	 		/* calculates (bytes / DEV_BSIZE) */ \
	((bytes) >> DEV_BSHIFT)
#define	dbtob(db)			/* calculates (db * DEV_BSIZE) */ \
	((db) << DEV_BSHIFT)

/*
 * Map a ``block device block'' to a file system block.
 * This should be device dependent, and will be if we
 * add an entry to cdevsw/bdevsw for that purpose.
 * For now though just use DEV_BSIZE.
 */
#define	bdbtofsb(bn)	((bn) / (BLKDEV_IOSIZE/DEV_BSIZE))

/*
 * Mach derived conversion macros
 */
#define i386_round_pdr(x)	((((unsigned)(x)) + NBPDR - 1) & ~(NBPDR-1))
#define i386_trunc_pdr(x)	((unsigned)(x) & ~(NBPDR-1))
#define i386_round_page(x)	((((unsigned)(x)) + NBPG - 1) & ~(NBPG-1))
#define i386_trunc_page(x)	((unsigned)(x) & ~(NBPG-1))
#define i386_btod(x)		((unsigned)(x) >> PDRSHIFT)
#define i386_dtob(x)		((unsigned)(x) << PDRSHIFT)
#define i386_btop(x)		((unsigned)(x) >> PGSHIFT)
#define i386_ptob(x)		((unsigned)(x) << PGSHIFT)

#ifndef KERNEL
/* DELAY is in locore.s for the kernel */
#define	DELAY(n)	{ register int N = (n); while (--N > 0); }
#endif