IRQ

I've used the example codes downloaded from ST website, and found an odd thing.I set a breakpoint at 'LDR PC, IRQ_Addr' in exception vectors, but it didn't stop when an IRQ interrupt occured(I set a breakpoint at IRQHandler, and it surely stopped).It really doesn't make sense that the ARM core executes the codes in IRQHandler without going through 'LDR PC, IRQ_Addr'.

I used the USB example.