I am in the process of porting ChibiOS to the xmega. I was wondering what the saving convention is for the RAMPD, RAMP[X,Y,Z] and EIND registers are? Are they call-used or call-saved?
I found this list of registers but it does not cover how the compiler handles these extended registers.
I noticed that RAMPZ appears pushed on the stack at the start of an ISR but none of the others.
I know these registers need to be saved during a context switch, just trying to figure out where I should save them.