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Re: [f-cpu] calling conventions



>Another proposal :
>
>r0            : zero
>r1            : pointer to variable or additional function arguments
>(call-clobbered)
>r2-r15     : function return values or arguments (call-clobbered)
>r16-r31   : temporary registers (call-clobbered)
>r32-r47   : local registers (callee-saver)
>r48-r63   : global or special registers
>
>that way we could handle pair of registers much smarter
>(r2-r3,r3-r4,...,r14,r15).

OK but this is another calling convention not usefull for most of
language becouse they don't allow multiple return value so these language
don't use some register.

And you must add a pointer to additional return if you want to return
more than 14 values.

>
>personally, I'm wondering if it is really necessary to limit
>function argument
>to r15 instead of r31 or r29 (to be sure to have at least a pair of
>temporary
>registers), in so far as we can consider that all function arguments
>not used
>by a function may be used as temporary registers by this function...

ok but if you want to have the minimum of dependencies in your code you
need some temp reg.
I think it was difficult in the start of your code if you have only 2
temp reg...

--
Thomas Lavergne                       "Le vrai rÍveur est celui qui rÍve
                                       de l'impossible."  (Elsa Triolet)
thomas.lavergne@laposte.net                                      
d-12@laposte.net    ICQ:#137121910     http://assoc.wanadoo.fr/thallium/


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