listing of interrupts

Having some problems with my irq's I am trying to find a complete listing of the irq's in use on my system. Up to now I have not found a complete list of the interrupts. With cat /proc/interrupts I get a list that did not show my TV card. Only after startinting to use xawtv I got the irq recognised. My second serial port which I have dedicated to my uninterupted powersupply and my parale port are not included also. Why can't all irq's be seen? By looking at the list I would assume that Knowing that they are there and can be used, I would asume that on my system I have two unused irq's. 6 and 13. Or are they also used ? How could I find out?