usr/src/sys/i386/include/param.h

/*-
 * Copyright (c) 1990 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     5.3 (Berkeley) %G%
 */

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

#define MACHINE "i386"

#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

#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   (512*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) */ \
        ((unsigned)(bytes) >> DEV_BSHIFT)
#define dbtob(db)                       /* calculates (db * DEV_BSIZE) */ \
        ((unsigned)(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))

#ifdef KERNEL
#ifndef LOCORE
int     cpuspeed;
#endif
#define DELAY(n)        { register int N = cpuspeed * (n); while (--N > 0); }

#else KERNEL
#define DELAY(n)        { register int N = (n); while (--N > 0); }
#endif KERNEL