As you can confirm from the table below except in FIQ
mode, registers r0-r12
are shared thus newly entered mode is responsible for not destroying previous mode's registers.
Organization of general-purpose registers and Program Status Registers
Domanda
A trivial question. In case of an IRQ should the irq_handler save r0-r12 on stack always or there can be exception to that.
AFAIK r0-r12 shd be saved.
Soluzione
As you can confirm from the table below except in FIQ
mode, registers r0-r12
are shared thus newly entered mode is responsible for not destroying previous mode's registers.
Organization of general-purpose registers and Program Status Registers