The ARM reference manual specifies sometimes MOV PC,R14 and sometimes SUBS PC,R14, #4 for returning from exceptions. But they have not mentioned why. Can somebdy expain?
Also, when exactly does the PC get incremented? During the Fetch ?
And exactly when (Fetching / Decoding / Executing) does an exception get generated?
Does an undefined instruction get generated when the instruction is decoded or when it is executed?What about Data and Prefetch aborts?