I am not familiar with how SDCC does it but in C calling convention the function does not have to know the number of parameters, therefore can not adjust the stack. Only the caller can do it.
-- Ori Idan CEO Helicon Books http://www.heliconbooks.com On Fri, Oct 21, 2022 at 6:00 PM Basil Hussain <ba...@stasisleak.uk> wrote: > On 21/10/2022 07:44, Philipp Klaus Krause wrote: > > The cleanup for stack parameters is done for both: for foo by the > > callee, for bar by the caller. Which one does it depends on the type > > of the function. For details, see section 4.5.1.1, "SDCC calling > > convention, version 1" in the manual: > > Argh, $*!% me, I did not notice this was the case. I usually work with > large memory model STM8 devices, but this is for a medium-only device, > and the void-returning function meets the criteria for callee stack > adjustment. >:( > > Can you briefly remind me what is the rationale behind void-returning > functions having the stack clean-up done by caller and not callee? One > of the things I prefer about the old calling convention is that it's > just so much simpler, without exceptions like this. > > Now I understand why 'i' was being trampled, as in my original code > function 'foo' is in fact a __naked inline assembly function, where I am > not cleaning the function arguments from the stack. > > Regards, > Basil Hussain > > P.S. By the way, now I am looking at the manual again, is there not a > mistake in section 4.5.1.2 describing calling convention version 0? It > says: > > > All parameters are passed on the stack. The stack is not adjusted for > > the parameters after the call (thus the callee has to do this > > instead), unless __z88dk_callee is specified. > > The second sentence is self-contradicting. Callee must adjust the stack, > unless you specify the option that says the callee will adjust the > stack!? I have never encountered functions that are attributed as > version 0 and SDCC does *not* generate stack rewind after calls to them > (i.e. caller SP rewind, not callee). > > > _______________________________________________ > Sdcc-user mailing list > Sdcc-user@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/sdcc-user >
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