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/* $OpenBSD: gateA20.c,v 1.2 1997/03/31 03:12:13 weingart Exp $ */
/*
* Ported to boot 386BSD by Julian Elischer (julian@tfs.com) Sept 1992
*
* Mach Operating System
* Copyright (c) 1992, 1991 Carnegie Mellon University
* All Rights Reserved.
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie Mellon
* the rights to redistribute these changes.
*/
#include <sys/types.h>
#include <machine/pio.h>
#include <stand.h>
#define K_RDWR 0x60 /* keyboard data & cmds (read/write) */
#define K_STATUS 0x64 /* keyboard status */
#define K_CMD 0x64 /* keybd ctlr command (write-only) */
#define K_OBUF_FUL 0x01 /* output buffer full */
#define K_IBUF_FUL 0x02 /* input buffer full */
#define KC_CMD_WIN 0xd0 /* read output port */
#define KC_CMD_WOUT 0xd1 /* write output port */
#define KB_A20 0xdf /* enable A20,
enable output buffer full interrupt
enable data line
enable clock line */
/*
* Gate A20 for high memory
*/
void
gateA20(on)
int on;
{
#ifdef IBM_L40
outb(0x92, 0x2);
#else IBM_L40
while (inb(K_STATUS) & K_IBUF_FUL);
while (inb(K_STATUS) & K_OBUF_FUL)
(void)inb(K_RDWR);
outb(K_CMD, KC_CMD_WOUT);
while (inb(K_STATUS) & K_IBUF_FUL);
if (on)
outb(K_RDWR, KB_A20);
else
outb(K_RDWR, 0xcd);
while (inb(K_STATUS) & K_IBUF_FUL);
while (inb(K_STATUS) & K_OBUF_FUL)
(void)inb(K_RDWR);
#endif IBM_L40
}
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