kbd_pac.c

开放源码实时操作系统源码.

/*
 * Copyright (c) 1999 Greg Haerr <[e-mail]>
 *
 * Copyright (c) 2000 Victor Rogachev <[e-mail]>
 *
 * Keyboard Driver, using BIOS for PACIFIC C on MSDOS
 */

#include "device.h"
#include <dos.h>
#include <conio.h>
 

static int  KBD_Open(KBDDEVICE *pkd);
static void KBD_Close(void);
static void KBD_GetModifierInfo(int *modifiers);
static int  KBD_Read(MWUCHAR *buf, int *modifiers);
static int  KBD_Poll(void);


KBDDEVICE kbddev = {
	KBD_Open,
	KBD_Close,
	KBD_GetModifierInfo,
	KBD_Read,
	KBD_Poll
};


/*
 * Open the keyboard
 */
static int
KBD_Open(KBDDEVICE *pkd)
{
	return 1;
}

/*
 * Close the keyboard.
 */
static void
KBD_Close(void)
{
}

/*
 * Return the possible modifiers for the keyboard.
 */
static  void
KBD_GetModifierInfo(int *modifiers)
{
	*modifiers = 0;			/* no modifiers available */
}

/*
 * This reads one keystroke from the keyboard, and the current state of
 * the mode keys (ALT, SHIFT, CTRL).  Returns -1 on error, 0 if no data
 * is ready, and 1 if data was read.  This is a non-blocking call.
 */
static int
KBD_Read(MWUCHAR *buf, int *modifiers)
{
        union REGS 	reg;

	/* wait until a char is ready*/
	if (!kbhit())
		return 0;

	/* read keyboard shift status*/
	reg.x.ax = 0x0200;
	int86(0x16, &reg, &reg);
	*modifiers = reg.x.ax;

	/* read keyboard character*/
	reg.x.ax = 0x1000;
	int86(0x16, &reg, &reg);
	*buf = (reg.x.ax & 0x00ff);

	if(*buf == 0x1b)	/* special case ESC*/
		return -2;
	return 1;
}

/*
**      Poll keyboard for char ready
*/
static int
KBD_Poll(void)
{
	if (kbhit())
		return 1;
	else
        	return 0;
}