[fpc-pascal] About FPC calling register like Delphi

[Alexandre Leclerc]

2007/1/26, Carlo Kok <ck at carlo-kok.com>:
> Michael Van Canneyt wrote:
> >
> > On Thu, 25 Jan 2007, Alexandre Leclerc wrote:
> >
> >> 2007/1/25, Felipe Monteiro de Carvalho <felipemonteiro.carvalho at gmail.com>:
> >>> On 1/25/07, Alexandre Leclerc <alexandre.leclerc at gmail.com> wrote:
> >>>> Yes, I understand that, but I *need* a scripting engine which is based
> >>>> on Pascal. And ROPS is the only one I found that answered my
> >>>> requirements. Also, it's integrated and it's "free", and very fast.
> >>>>
> >>>> If there was another way, I would use it. But since, I must rely on a
> >>>> stable FPC internal to make it work.
> >>> Does this script support other calling conventions?
> >>>
> >>> You could try using stdcall instead of register. It´s much simpler,
> >>> and as stable as it can get.
> >>>
> >>> I remember writing a simple script engine myself, and then I choose to
> >>> support mostly stdcall.
> >> ROPS (RemObjects Pascal Script remobjects.com) is 100% pascal code
> >
> > Not 100%, there is 1 routine which is assembler, it's the routine
> > that sets up the stack when making a call to an imported function.
> >
> >> that you simply use in your own code. The engine compiles in your
> >> application. It then work with the application stack, etc. to execute
> >> native pascal functions and script functions. Quite a nice script
> >> engine.
> >
> > I use it since ages, even when it was not owned by remobjects.
>
> You are right about that. There is a routine that does that, but all it
> does is copy the prepared data onto the stack (And copy back the
> result). Now, there are a few problems with PS related to FPC:
>
> * FPC has changed default calling convention once (or twice?)
> * The way "register" works on FPC is slightly different from delphi, in
> delphi special types like interfaces, strings and variant results are
> passed as var parameters, it seems the easiest fix would be for me to
> change PascalScript to process results differently for FreePascal.
>
> How does FPC pass a string/variant/interface result actually? Returned
> in AEX?
>
>
> Once I know this, I should be able to add an FPCFIX define for this. (So
> it can be easily undone when FPC supports the same "Register" mode as
> Delphi does)

Carlo,

I was planning to build a small application to serve as a regression
test (by testing some features of PS in FPC) in order to find quickly
any problems. I was planning to do this in couple weeks. If this
interest you, I can send you the code after so that it will become
easier for you to test any feature that is broken in FPC.

-- 
Alexandre Leclerc