57 lines
2.1 KiB
C
57 lines
2.1 KiB
C
/* $NetBSD: diskbuf.c,v 1.6 2005/12/11 12:17:48 christos Exp $ */
|
|
|
|
/*
|
|
* Copyright (c) 1996
|
|
* Matthias Drochner. All rights reserved.
|
|
*
|
|
* 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.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
|
|
*
|
|
*/
|
|
|
|
/* data buffer for BIOS disk / DOS I/O */
|
|
|
|
#include <lib/libsa/stand.h>
|
|
#include "diskbuf.h"
|
|
|
|
char *diskbufp; /* allocated from heap */
|
|
|
|
const void *diskbuf_user;
|
|
|
|
/*
|
|
* Global shared "diskbuf" is used as read ahead buffer.
|
|
* This MAY have to not cross a 64k boundary.
|
|
* In practise it is allocated out of the heap early on...
|
|
* NB a statically allocated diskbuf is not guaranteed to not
|
|
* cross a 64k boundary.
|
|
*/
|
|
char *
|
|
alloc_diskbuf(const void *user)
|
|
{
|
|
diskbuf_user = user;
|
|
if (!diskbufp) {
|
|
diskbufp = alloc(DISKBUFSIZE);
|
|
if (((int)diskbufp & 0xffff) + DISKBUFSIZE > 0x10000) {
|
|
printf("diskbufp %x\n", (unsigned)diskbufp);
|
|
panic("diskbuf crosses 64k boundary");
|
|
}
|
|
}
|
|
return diskbufp;
|
|
}
|