Hi All, I am trying to understand how the interrupt handler in arm working.By looking at the code,what I understood,when an interrupt happens arm disables the irq, saves the cpsr to spsr,save current pc to lr and switches to irq mode. So in case of interrupt it branches to the vector_irq and there it saves some registers and depending on which context its happened,it will call __irq_user or __irq_svc.But before that it switches to the supervisory mode. Here I got confused,because in this case user registered handler will be executed in supervisory mode. I was thinking interrupt handler will always be executed in interrupt mode. Could any one please give some pointers on this. -- With Regards Subin Gangadharan I am not afraid and I am also not afraid of being afraid.