freebsd-dev/sys/i386/include/param.h
David Greenman fb1322e408 Decrease MCLBYTES from 4k back to 2k. It isn't likely that we'll be doing
page flipping anytime soon and 4k just wastes memory. Performance via the
looback interface will decrease slightly by this change. Idealy, we need
buffers that can have variable sizes, but this requires a rewrite of far
too much code at the moment.
1995-01-23 19:21:49 +00:00

169 lines
6.0 KiB
C

/*-
* 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.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from: @(#)param.h 5.8 (Berkeley) 6/28/91
* $Id: param.h,v 1.16 1994/09/18 22:05:22 bde Exp $
*/
#ifndef _MACHINE_PARAM_H_
#define _MACHINE_PARAM_H_
/*
* Machine dependent constants for Intel 386.
*/
#define MACHINE "i386"
#define MID_MACHINE MID_I386
/*
* Round p (pointer or byte index) up to a correctly-aligned value
* for all data types (int, long, ...). The result is unsigned int
* and must be cast to any desired pointer type.
*/
#define ALIGNBYTES (sizeof(int) - 1)
#define ALIGN(p) (((unsigned)(p) + ALIGNBYTES) & ~ALIGNBYTES)
/* XXX PGSHIFT and PG_SHIFT are two names for the same thing */
#define PGSHIFT 12 /* LOG2(NBPG) */
#define PAGE_SHIFT 12
#define NBPG (1 << PAGE_SHIFT) /* bytes/page */
#define PAGE_SIZE (1 << PAGE_SHIFT)
#define PAGE_MASK (PAGE_SIZE-1)
#define PGOFSET (NBPG-1) /* byte offset into page */
#define NPTEPG (NBPG/(sizeof (pt_entry_t)))
/* XXX PDRSHIFT and PD_SHIFT are two names for the same thing */
#define PDRSHIFT 22 /* LOG2(NBPDR) */
#define NBPDR (1 << PDRSHIFT) /* bytes/page dir */
#define PDROFSET (NBPDR-1) /* byte offset into page dir */
/*
* XXX This should really be KPTDPTDI << PDRSHIFT, but since KPTDPTDI is
* defined in pmap.h which is included after this we can't do that
* (YET!)
*/
#define BTOPKERNBASE (KERNBASE >> PGSHIFT)
#define DEV_BSHIFT 9 /* log2(DEV_BSIZE) */
#define DEV_BSIZE (1 << DEV_BSHIFT)
#define BLKDEV_IOSIZE 2048
#define MAXPHYS (64 * 1024) /* max raw I/O transfer size */
#define CLSIZELOG2 0
#define CLSIZE (1 << CLSIZELOG2)
/* 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.
*/
#ifndef MSIZE
#define MSIZE 128 /* size of an mbuf */
#endif /* MSIZE */
#ifndef MCLSHIFT
#define MCLSHIFT 11 /* convert bytes to m_buf clusters */
#endif /* MCLSHIFT */
#define MCLBYTES (1 << MCLSHIFT) /* size of an m_buf cluster */
#define MCLOFSET (MCLBYTES - 1) /* offset within an m_buf cluster */
#ifndef NMBCLUSTERS
#ifdef GATEWAY
#define NMBCLUSTERS 512 /* map size, max cluster allocation */
#else
#define NMBCLUSTERS 256 /* map size, max cluster allocation */
#endif /* GATEWAY */
#endif /* NMBCLUSTERS */
/*
* 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))
/*
* Mach derived conversion macros
*/
#define trunc_page(x) ((unsigned)(x) & ~(NBPG-1))
#define round_page(x) ((((unsigned)(x)) + NBPG - 1) & ~(NBPG-1))
#define atop(x) ((unsigned)(x) >> PG_SHIFT)
#define ptoa(x) ((unsigned)(x) << PG_SHIFT)
#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)
#endif /* !_MACHINE_PARAM_H_ */