On 30/11/2005 01:06 Am, alex wrote:
> At 12:23 PM -0900 11/30/05, Mike Kluev wrote:
>> On Wed, 30 Nov 2005 10:58:03, Chris Hanson <email@hidden> wrote:
>>
>>> On Nov 29, 2005, at 2:10 PM, Chris Espinosa wrote:
>>>
>>>> The 'pascal' keyword actually became a no-op in the transition to
>>>> PowerPC more than ten years ago. It specified whether arguments
>>>> should be pushed on the calling stack in left-to-right or right-to-
>>>> left order. Because PowerPC passes function arguments in
>>>> registers, 'pascal' is meaningless in the PowerPC ABI.
>>>
>>> With enough function arguments ? or the right combination of types of
>>> function arguments, if I remember correctly ? PowerPC still requires
>>> arguments to be pushed onto the stack. However, the PowerPC ABI
>>> declared that all arguments must be pushed in left-to-right order for
>>> interop purposes, keeping the "pascal" keyword meaningless.
>>
>> left-to-right? Is that not a problem for var-arg functions?
>
> Also I remember that pascal expects the caller to cleanup to the stack whereas
> in C the callee cleans up the stack. (perhaps I have this reversed)...
Yep, the reverse is true. It is easy to remember: this is C who has
var-arg functions and the callee can't clean up the stack for those
because it doesn't know how many of those.
> There was also something about whether or not to return values on the stack
> but I believe that too is covered in the PowerPC ABI. I assume the stack
> cleanup issues are also addressed (namely by simply using registers instead of
> the stack)?
Even when all params fit in registers, the PPC ABI reserves space for
them on the stack (however insane this sounds).
> Other the years the whole going from Pascal to C on a 68k and then going from
> 68k to PPC and now to Intel has really 'done a number' on my facilities to
> find useful information in my brain at a reasonable speed. I doubt that it's
> solely the Mac's fault ;-)
Mike
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