55 lines
1.2 KiB
C
55 lines
1.2 KiB
C
/*
|
|
* $NetBSD: gatea20.c,v 1.2 1997/10/29 00:32:49 fvdl Exp $
|
|
*/
|
|
|
|
/* extracted from freebsd:sys/i386/boot/biosboot/io.c */
|
|
|
|
#include <sys/cdefs.h>
|
|
__FBSDID("$FreeBSD$");
|
|
|
|
#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");
|
|
}
|