Re: [cc65] calling conventions

Good morning!

On Sat, Mar 07, 2009 at 01:38:54AM +0100, Groepaz wrote:
> i have a dumb question... a function written in assembler (which is called
> from C) that returns an unsigned char, does it have to set the Y register to
> 0 before returning? so far i assumed yes, is that true? and does that
> requirement change if the function is declared __fastcall__ ?

If you're talking about the X register, then yes. The compiler assumes that
the default promotions are already done, so when returning chars, the X
register has to be set. This does not depend on the __fastcall__ property of
the function.

If you're really talking about the Y register then no, it does not have to be
set on return.

Regards


        Uz


-- 
Ullrich von Bassewitz                                  uz@musoftware.de
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