Re: [PATCH/RFC/RFA] Print in-memory struct return values

[Andreas Schwab <schwab@suse.de>]

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Mark Kettenis <kettenis@chello.nl> writes:

> Anyway, to what extent are the m68k ABI's documented to return the
> structure return address in %d0 and/or %a0?  For the
> PCC_STATIC_STRUCT_RETURN targets this is clear, but how is this for
> the systems where the caller is supposed to pass the memory area.  Do
> you have access to the m68k SVR4 ABI?  What does it say about this?

From the 68000 supplement:

    Functions Returning Structures or Unions

    As mentioned above, when a function returns a structure or union, it
    expects the caller to provide space for the return value and to place
    its address in register %a0.  Having the caller supply the return
    object's space allows re-entrancy.

    A function returning a structure or union also sets %a0 to the value
    it finds in %a0.  Thus when the caller receives control again, the
    address of the returned object resides in register %a0.  ...

Andreas.

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Andreas Schwab, SuSE Labs, schwab@suse.de
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