freebsd-src/sys/i386/include/param.h
Bruce Evans bb2038d538 Improved the btodb() and dbtob() macros. I made them give unsigned
[long long] results when I last worked on them, but they are normally
used together with to daddr_t's and off_t's which are signed, so the
unsigned results did little except cause warnings.
1996-10-06 19:24:02 +00:00

129 lines
4.6 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 1.22 1996/05/03 21:01:18 phk 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)
#define PAGE_SHIFT 12 /* LOG2(PAGE_SIZE) */
#define PAGE_SIZE (1<<PAGE_SHIFT) /* bytes/page */
#define PAGE_MASK (PAGE_SIZE-1)
#define NPTEPG (PAGE_SIZE/(sizeof (pt_entry_t)))
#define NPDEPG (PAGE_SIZE/(sizeof (pd_entry_t)))
#define PDRSHIFT 22 /* LOG2(NBPDR) */
#define NBPDR (1<<PDRSHIFT) /* bytes/page dir */
#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 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 */
/*
* Some macros for units conversion
*/
/* clicks to bytes */
#define ctob(x) ((x)<<PAGE_SHIFT)
/* bytes to clicks */
#define btoc(x) (((unsigned)(x)+PAGE_MASK)>>PAGE_SHIFT)
/*
* btodb() is messy and perhaps slow because `bytes' may be an off_t. We
* want to shift an unsigned type to avoid sign extension and we don't
* want to widen `bytes' unnecessarily. Assume that the result fits in
* a daddr_t.
*/
#define btodb(bytes) /* calculates (bytes / DEV_BSIZE) */ \
(sizeof (bytes) > sizeof(long) \
? (daddr_t)((unsigned long long)(bytes) >> DEV_BSHIFT) \
: (daddr_t)((unsigned long)(bytes) >> DEV_BSHIFT))
#define dbtob(db) /* calculates (db * DEV_BSIZE) */ \
((off_t)(db) << DEV_BSHIFT)
/*
* Mach derived conversion macros
*/
#define trunc_page(x) ((unsigned)(x) & ~PAGE_MASK)
#define round_page(x) ((((unsigned)(x)) + PAGE_MASK) & ~PAGE_MASK)
#define atop(x) ((unsigned)(x) >> PAGE_SHIFT)
#define ptoa(x) ((unsigned)(x) << PAGE_SHIFT)
#define i386_btop(x) ((unsigned)(x) >> PAGE_SHIFT)
#define i386_ptob(x) ((unsigned)(x) << PAGE_SHIFT)
#endif /* !_MACHINE_PARAM_H_ */