Hullo guys , I had to write my own assembly subroutines to be called from C files . From the ARM Cortex-M documentation , it's clear that when an interrupt occur , only R0->R3 , R12 are pushed into stack . So for safe operation , those 're the only registers allowed to be used when interrupts 're enabled ?
well , Per Westermark , so the best thing is to push the rest of the registers at the very beginning of the ISR , and then pop them at the very end of it ? (the ISR will be in C) , or u have another better suggestion . >>> Thx in advance