Calling a C function from Assembly
Posted: Wed Dec 21, 2022 6:47 pm
by giltal
ESP32:
I have an interrupt service routine written in Assembly
I am trying to call a C function and get a double exception error.
Any Idea?
movi a14, intFunc
callx0 a14
extern "C" void IRAM_ATTR intFunc()
{
counter2++;
}
Re: Calling a C function from Assembly
Posted: Thu Dec 22, 2022 2:38 am
by Sprite
The ESP32 uses the windowed ABI; rather than callx0 you should use one of callx4, callx8 or callx12. Note that if you want to pass arguments to the C function, this also shifts the registers these argument are passed in.
Re: Calling a C function from Assembly
Posted: Fri Dec 23, 2022 12:02 pm
by giltal
Thanks for your answer ...
I am aware of it
Tried all options, still same starnge behaviuor