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Re: Addressing 2GS slots with Orca Pascal?



In article <pHsE9.1077$l45.358588@news20.bellglobal.com>,
 Yves McDonald <""yves.mcdonald\"@NO SPAM sympatico.ca> wrote:

> Hello Apple 2 fans,
> 
> I'm an experienced Apple ][+, //e programmer but a newbie when it comes 
> to Apple 2GS 16-bit mode.  I whish to experiment with a sprite card 
> based on TI's TMS9918A chip.  I'd like to use Orca PASCAL for this 
> instead of fiddling with PEEKs and POKES and their negative decimal 
> addresses and data or using assembler which is tedious to use for a 
> first try.  I'll use assembler later on to write a more efficient device 
> driver.  Anyway, here's my question: is there a PASCAL programming trick 
> to access memory space dedicated to slot 1-7?  On the same line of 
> thought,  are there online reference on GS hardware architecture?  I 
> have the Toolbox reference books vol. 1 and 2 but I miss the rest of 
> official Apple 2gs book collection.
> 
> Thanks,
> 
> Yves
> 
> 

Try declaring a pointer type and then use the Pointer function to turn 
the integer representation of the slot address into a pointer. There is 
an example in the ORCA Pascal manual under the ORD(4) function that is 
close.

Let us know if that works because it would be most handy (if I ever 
write another Pascal program. The last one I wrote was in 1989 and 
before that from 1982-1984 when Pascal was the Java of its time ;)