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Q about LIBCALL_VALUE in machine.h


Hi all,

I'm looking at the description of LIBCALL_VALUE (and its cousin FUNCTION_VALUE) in the GCC Internals manual, and I'm also looking at all the different machine.h files in gcc. None of these seem to address a question I have.

Suppose my processor has only four 8-bit registers, A through D.

I can have LIBCALL_VALUE/FUNCTION_VALUE return register A for QImode, HImode, and SImode, since I have 32 bits of registers available. However, what should I return for DImode? I need 64 bits, but I don't have enough registers.

I suspect that this is where BLKmode would come in, but I am not sure how to use that. What happens if FUNCTION_VALUE is called with DImode? What should I return?

Thanks for any help!

--Rob


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