External interrupt not triggering software exception

I currently hav a push button connected up to my IRQ input on my Nios. When the button is asserted, I expect to see my program counter jump to my exceptions section in my assembly source code. When the button is asserted, I do not see this behavior. I have enabled both the ienable bit for the 0th interrupt, and the status bit PIE.

Any ideas why my exception is not executing?