/* 
 * Copyright 2010 Stefan Lankes, Chair for Operating Systems,
 *                               RWTH Aachen University
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * This file is part of MetalSVM.
 */

#include <metalsvm/stdio.h>
#include <metalsvm/string.h>
#include <asm/kb.h>
#include <asm/irq.h>

#ifdef USE_KEYBOARD

/* 
 * KBDUS means US Keyboard Layout. This is a scancode table
 * used to layout a standard US keyboard. I have left some
 * comments in to give you an idea of what key is what, even
 * though I set it's array index to 0. You can change that to
 * whatever you want using a macro, if you wish! 
 */
static const unsigned char kbdus[128] = { 0, 27, '1', '2', '3', '4', '5', '6', '7', '8',	/* 9 */
	'9', '0', '-', '=', '\b',	/* Backspace */
	'\t',			/* Tab */
	'q', 'w', 'e', 'r',	/* 19 */
	't', 'y', 'u', 'i', 'o', 'p', '[', ']', '\n',	/* Enter key */
	0,			/* 29   - Control */
	'a', 's', 'd', 'f', 'g', 'h', 'j', 'k', 'l', ';',	/* 39 */
	'\'', '`', 0,		/* Left shift */
	'\\', 'z', 'x', 'c', 'v', 'b', 'n',	/* 49 */
	'm', ',', '.', '/', 0,	/* Right shift */
	'*', 0,			/* Alt */
	' ',			/* Space bar */
	0,			/* Caps lock */
	0,			/* 59 - F1 key ... > */
	0, 0, 0, 0, 0, 0, 0, 0, 0,	/* < ... F10 */
	0,			/* 69 - Num lock */
	0,			/* Scroll Lock */
	0,			/* Home key */
	0,			/* Up Arrow */
	0,			/* Page Up */
	'-', 0,			/* Left Arrow */
	0, 0,			/* Right Arrow */
	'+', 0,			/* 79 - End key */
	0,			/* Down Arrow */
	0,			/* Page Down */
	0,			/* Insert Key */
	0,			/* Delete Key */
	0, 0, 0, 0,		/* F11 Key */
	0,			/* F12 Key */
	0,			/* All other keys are undefined */
};

/* Handles the keyboard interrupt */
static void keyboard_handler(struct regs *r)
{
	unsigned char scancode;

	/* Read from the keyboard's data buffer */
	scancode = inportb(0x60);

	/* 
	 * If the top bit of the byte we read from the keyboard is
	 * set, that means that a key has just been released 
	 */
	if (scancode & 0x80) {

		/* 
		 * You can use this one to see if the user released the
		 * shift, alt, or control keys... 
		 */
	} else {

		/* 
		 * Here, a key was just pressed. Please note that if you
		 * hold a key down, you will get repeated key press
		 * interrupts. 
		 */

		/* Just to show you how this works, we simply translate
		 * the keyboard scancode into an ASCII value, and then
		 * display it to the screen. You can get creative and
		 * use some flags to see if a shift is pressed and use a
		 * different layout, or you can add another 128 entries
		 * to the above layout to correspond to 'shift' being
		 * held. If shift is held using the larger lookup table,
		 * you would add 128 to the scancode when you look for it 
		 */
		kputchar(kbdus[scancode]);
	}
}

/* Installs the keyboard handler into IRQ1 */
void keyboard_init(void)
{
	irq_install_handler(1, keyboard_handler);
}

#endif