kbd.c

#include "io.h"
/* Scancode-to-ASCII conversion table
 * US Keyboard Layout
 * Usage:
 *    unsigned char myChar = kdbUS[unsigned char scancode];
 *
 * From http://www.osdever.net/bkerndev/Docs/keyboard.htm
 */


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

    /* Read from the keyboard's data buffer */
    scancode = inb(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 */
        write(kbdUS[scancode], 10, 80);
    }
}