#include <system.h>

/* 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! */


unsigned char KBDUS[128] =
{
    0,  27, '!', '"', '4', '$', '%', '&', '/', '(', /* 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 */
 '\'', '`',   1,        /* Left shift */
 '\\', 'Z', 'X', 'C', 'V', 'B', 'N',            /* 49 */
  'M', '?', 0, '/',   0,                    /* Right shift */
  '*',
    0,  /* Alt */
  ' ',  /* Space bar */
    2,  /* 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 */
};

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 */
 '\'', '`',   1,        /* Left shift */
 '\\', 'z', 'x', 'c', 'v', 'b', 'n',            /* 49 */
  'm', ',', '.', '/',   0,                  /* Right shift */
  '*',
    0,  /* Alt */
  ' ',  /* Space bar */
    2,  /* 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 */
void keyboard_handler(struct regs *r)
{
    unsigned char scancode;
    unsigned short int SHIFT = 0;
    unsigned short int CAPS = 0;

    /* 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 */

    //En castellano: si el bit mas significativo del byte leido desde el teclado esta en alto, significa q acabas de soltar la tecla
    if (scancode & 0x80)
    {
        if(kbdus[scancode]  == 1) //Si suelto LEFT SHIFT
         {
             SHIFT = 0;   //Bajo su FLAG
            }
    }
    else
    {
         if(kbdus[scancode] == 1)   //Si apreto LEFT SHIFT. En la funcion kdus esta mapeado de tal manera que
         {                          // cuando se aprete shift, se devuelva un 1
             SHIFT = 1;     //Subo su FLAG
            }
         if(kbdus[scancode] == 2)   //Si apreto CAPS LOCK. Lo mismo para el CAPSLOCK o BLOQMAYUS, se devuelve un 2 del arreglo kbdus
         {
             CAPS++;
            }

         if( (SHIFT == 1) || ((CAPS%2)==1) )    //Si estoy apretando SHIFT o aprete CAPSLOCK un nº impar de veces
         {                                      //voy a la tabla de mayusculas
             putch(KBDUS[scancode]);
            }
         else    putch(kbdus[scancode]);
    }
}

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