Oracle Forms

Hi Friends

I have created chess game on Oracle Developer Form 2000 6i & my problem is that i have created some function for moving of Bishops, Kings, Queen, Knight etc. on Push Button and my Function of Knight is ..

FUNCTION check_move_knight(p_from in varchar2, p_to in varchar2) RETURN BOOLEAN IS

BEGIN
If
abs(substr(p_from, 2,1) - substr(p_to, 2,1)) = 2 and
abs(substr(p_from, 4,1) - substr(p_to, 4,1)) = 1
or
abs(substr(p_from, 2,1) - substr(p_to, 2,1)) = 1 and
abs(substr(p_from, 4,1) - substr(p_to, 4,1)) = 2

then
return true;
else
return false;
END IF;

END;

I want to write Function of King and Queen please tell me which type of function i can write on form ... :)

Thanks & Regards
Adeel