[OpenBIOS] Dictionary size limit per device instance

[Asif Haswarey]

Ok, I found out what the problem is!
It's the FCode-Number limit, ie. 0x0fff.
For details please look at:
OpenFirmware IEEE-1275 (1994) spec. section 2.3.43.

If I got this right, I am allowed to define/declare only 0x0fff number of
constants and/or functions, variables, defers etc. for which the
tokenizer assigns a FCode-Number in the final tokenized FCode image.
Please look at the constant symbol FCODE_LIMIT in nextfcode.h
in fcode-utils-1.0.2 suite at:
http://www.openbios.org/viewvc/fcode-utils.tar.gz?view=tar&root=OpenBIOS&pathrev=113

Now given that today we have complex feature rich PCI based
plugin cards, I can see FCode images of size 50K+ in order to
support the various features. I don't expect to see a revision of the
original OpenFirmware IEEE-1275 (1994) spec., but should we reconsider this
FCode-Number limitation?

Moreover, I am actually running into this limitation for one of our PCI-E
plugin cards!
_____________
Äsif Haswaréy
QLogic Corporation
FCode Driver Development


-----Original Message-----
From: openbios-bounces at openbios.org [mailto:openbios-bounces at openbios.org] On Behalf Of David L. Paktor
Sent: Wednesday, August 22, 2007 7:30 PM
To: The OpenBIOS Mailinglist
Subject: Re: [OpenBIOS] Dictionary size limit per device instance

Asif Haswarey wrote:
>> With that arrangement, the amount of dictionary space available to plug-in device drivers was virtually unlimited! 
>>     
>
> Weel, I ran into this problem while testing (QLogic iSCSI) FCode I had developed for the SPARC.
> I experimented with a dummy fcode consisting of only constant declarations.
> The FCode failed to get interpreted when the total tokenized size 
> reached just a little above 50KB (that's kilo-bytes). Unfortunately I system OBP would not let me use the "here"
> word to find out the exact size of the dictionary space my dummy FCode 
> used up. So I figured the dictionary space available for my FCode is 
> basically a portion of the overall dictionary space available to the 
> system. In short, every device FCode has a limit of dictionary space available to it.
>
> Is my understand correct? If so, then this is what my question is about concerning OpenBIOS.
>   

Well, it's not an inherent characteristic of Open Firmware, nor of OBP.  
It might depend on the
platform where you were running your test.  If it was one of the E{3..6}{0,5}00 servers, that would be consistent.  Incidentally, what happened when you hit the limit?

As for seeing "here" from FCode:

defer my_here
 '  noop to my_here
" here" $find if  to my_here  then

( you might need a  "drop"  after  the "if"; I forgot whether  $find returns just the XT or the "immediate" indicator, too...)

Then you can rock'n'roll with  my_here  to show you where you are...

-- 

David L. Paktor             dlpaktor at netscape.net


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