Get key cpctelera

 cpct_keyID getKey() {

  // Traverse the keystatus vector from end to start, to help
  // the compiler better optimize this code
  u8 i = 10, *keys = cpct_keyboardStatusBuffer + 9;
  u16 keypressed;
 
  // Wait for a keypress
  do { cpct_scanKeyboard(); } while ( ! cpct_isAnyKeyPressed() );

  // Analyse which key has been pressed and return its keycode
  do {
    // We analyse groups of keys byte by byte (8 by 8, 1 bit per key)
    // If no single key is pressed in this group, all bits will be on, and the byte will be 0xFF
    // Then, XORing the byte with 0xFF will result in 0 unless some key from this group is pressed
    keypressed = *keys ^ 0xFF;
    if (keypressed)
       return (keypressed << 8) + (i - 1); // Convert to cpct_keyID format: 8 first bits = key mask, 8 next bits, keyboard row (0-9)
    --keys;
  } while(--i);

  // No key was pressed
  return 0;
}