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Date: Wed, 31 Dec 2003 16:35:42 -0500
From: Hyman Rosen <hyrosen@mail.com>
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Subject: Re: GNAT parameter passing, C-style?
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Date: 2003-12-31T16:35:42-05:00
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Frank J. Lhota wrote:
 > Of course, passing parameters by registers avoids all of these issues,
 > since nothing is pushed onto or popped off the stack.

On the contrary, using registers exacerbates these issues, since
there can never be enough registers to hold all possible arguments.
If you call a function with enough parameters, eventually there will
be too many to fit, and the remaining arguments will be passed on the
stack. The "stdarg.h" header is meant to be implementation magic; the
compiler knows all about the particular paramater passing scheme, and
will fix things up as needed to make it all work.