Dear All. Good Evening. I am trying to find out how many instructions can be executed between an asynchronous exception is triggered and the handler is entered (for making sure that the behaviour of PendSV is the desired one, as at some point we will use blocking synchronization primitives) For the case of re activating interrupts, I found it here: http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dai0321a/BIHBFEIB.html For Cortex M-4, i apparently found it here, is one instruction: http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0553a/BABBGBEC.html For Cortex M-0, i can't find it, it probably should be here, but it is not specified, it is simply plural.. http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0497a/BABBGBEC.html Does anyone know about any reference or document where it can be found, just to speed up the searching process? Thanks in advance! With Warm Regards, Ivan Raul