NetBSD/sys/arch/i386/stand/lib/gatea20.c

45 lines
1.1 KiB
C

/* $NetBSD: gatea20.c,v 1.1.1.1 1997/03/14 02:40:32 perry Exp $ */
/* extracted from freebsd:sys/i386/boot/biosboot/io.c */
#include <sys/types.h>
#include <machine/pio.h>
#include <lib/libsa/stand.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,
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()
{
#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);
outb(K_RDWR, x_20);
while (inb(K_STATUS) & K_IBUF_FUL);
#endif IBM_L40
}