Re: [OpenBIOS] Help with local variables

[Programmingkid]

Thank you very much for all your help. I only wish there was documentation available on how to add words. Maybe I should make a tutorial and send it to the person in charge of the OpenBIOS website.

On Feb 24, 2010, at 6:00 AM, [e-mail] wrote:
> Message: 5
> Date: Wed, 24 Feb 2010 10:13:23 +0000
> From: Mark Cave-Ayland 
> To: The OpenBIOS Mailinglist 
> Subject: Re: [OpenBIOS] Help with local variables
> Message-ID: 
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> G 3 wrote:
> > Hi, I am working on implementing local variable support in OpenBIOS. I 
> > have done a lot of research on the issue, but there are a few issues I 
> > still need help resolving.
> >
> > -Does Openbios context switch when a word is called? This is when all 
> > the registers are saved into a stack frame, so the currently executing 
> > word can use them.
>
> I think you are looking too low a level here - all of this is handled 
> automatically by the Forth engine.
> > -Could someone give me a tutorial on how to add c functions to forth and 
> > make them accessible to the interpreter. I want to be able to add words 
> > to the dictionary and be able to use them from the command line.
>
> The easiest way to look at this is to look at one of the existing 
> primitive words such as DOCOL. But in short:
>
> Add the new word to the end of the wordnames array in kernel/bootstrap.c
>
> Add the C function name to the end of the words array in
>
> kernel/primitives.c
> Add the C function to kernel/internal.c
> > Would anyone know which register on the PowerPC would be good for
> >
> > using as a stack pointer for a new local variable stack? I think r13 is 
> > free and a possible candidate.
>
> Again, you're looking at too low a level here. What I believe you need 
> to do is create a word that adds a new dictionary to the search list at 
> the start of the function, much in the same way that a package instance 
> does.
>
> HTH,
>
> Mark.
>
> Sirius Labs: http://www.siriusit.co.uk/labs

Help with local variables

[Stefan Reinauer]

On 2/25/10 4:45 PM, Programmingkid wrote:
> Thank you very much for all your help. I only wish there was
> documentation available on how to add words. Maybe I should make a
> tutorial and send it to the person in charge of the OpenBIOS website.

If you want a wiki account, let me know.

Stefan