/*
 File: simple_keyboard.C
 
 Author: R. Bettati
 Department of Computer Science
 Texas A&M University
 Date  : 2017/06/30
 
 Simple control of the keyboard.
 */

/*--------------------------------------------------------------------------*/
/* DEFINES */
/*--------------------------------------------------------------------------*/

/* (none) */

/*--------------------------------------------------------------------------*/
/* INCLUDES */
/*--------------------------------------------------------------------------*/

#include "assert.H"
#include "machine.H"
#include "console.H"
#include "interrupts.H"
#include "simple_keyboard.H"

/*--------------------------------------------------------------------------*/
/* CONSTRUCTOR */
/*--------------------------------------------------------------------------*/

SimpleKeyboard::SimpleKeyboard() {
    key_pressed = false;
}

/*--------------------------------------------------------------------------*/
/* METHODS FOR CLASS   S i m p l e K e y b o a r d */
/*--------------------------------------------------------------------------*/

void SimpleKeyboard::handle_interrupt(REGS *_r) {
    /* What to do when keyboard interrupt occurs? In this case, we update
     "key_pressed". */
    
    unsigned char status = Machine::inportb(STATUS_PORT);
    /* lowest bit of status will be set if buffer is not empty. */
    if (status & 0x01) {
        char kc = Machine::inportb(DATA_PORT);
        if (kc >= 0) {
            key_pressed = true;
            key_code = kc;
        }
    }
}

void SimpleKeyboard::wait() {
    /* Loop until the user presses a key. */
    
    kb.key_pressed = false;
    
    while(kb.key_pressed == false);
    
}

char SimpleKeyboard::read() {
    /* Loop until the user presses a key, and then return the keycode. */
    kb.key_pressed = false;
    
    while (kb.key_pressed == false);
    
    return kb.key_code;
}

SimpleKeyboard SimpleKeyboard::kb;

void SimpleKeyboard::init() {
    InterruptHandler::register_handler(1, &kb);
}