Sets an interrupt vector. 

Usage: 
{{{
LDX MSB
LDY LSB
LDA (value see table below)
JSR $E45C
}}}
||Register||Value
|X|MSB
|Y|LSB
|A|vector to be changed, see below

||Value||Vector
|0|[VIMIRQ]
|1|[TIMCOUNT1]
|2|[TIMCOUNT2]
|3|[TIMCOUNT3]
|4|[TIMCOUNT4]
|5|[TIMCOUNT5]
|6|[VVBLKI]
|7|[VVBLKD]


----
see also: [VBI Vertical Blank Interrupt]