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/*
* $FreeBSD$
* From: $NetBSD: gatea20.c,v 1.2 1997/10/29 00:32:49 fvdl Exp $
*/
/* extracted from freebsd:sys/i386/boot/biosboot/io.c */
#include <stand.h>
#include <machine/cpufunc.h>
#include <bootstrap.h>
#include "libi386.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 0x9f /* enable A20,
reset (!),
enable output buffer full interrupt
enable data line
disable clock line */
/*
* Gate A20 for high memory
*/
static unsigned char x_20 = KB_A20;
void gateA20()
{
__asm("pushfl ; cli");
#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);
delay(100);
while (inb(K_STATUS) & K_IBUF_FUL);
outb(K_RDWR, x_20);
delay(100);
while (inb(K_STATUS) & K_IBUF_FUL);
#endif /* IBM_L40 */
__asm("popfl");
}
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