Re: A86: Asm-86 12k cap


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Re: A86: Asm-86 12k cap




Hmm....

In a message dated 4/29/98 9:15:40 PM Central Daylight Time,
assets@eden.rutgers.edu writes:

> Can a RAM page be put out port 5?  I know that a ROM page can be put out
port 
> 6.
>  
>  If you put the first 12k out port five, you could add another 16k using
port 
> 6.
>  The only
>  problem is that the ROM call emulation would probably have to be changed (
> not
>  having
>  page $0d), but since you would have to check for ROM versions, you could
use
>  that
>  call on page 0 that swaps the page back after it's finished or just use the
>  calls on page
>  0.  Who knows? ... that might even get it to emulate faster.
>  
>  Kirk Meyer wrote:
>  
>  > that's not possible.  the way 85 programs are simulated is an 85-like
>  > environment is created from $8000-$BFFF in the 86 memory on RAM page 1,
>  > which can be used for this purpose.  since program execution on an 85 
> starts
>  > at about $9000 (or even later), this leaves only 12K of RAM page 1 to be
>  > used by programs.  you cannot use beyond the $BFFF address because $C000 
> is
>  > used by _getky routines and even if you move that data somewhere else
>  > temporarily, lots of things would be corrupted (if you didn't understand
>  > that sentence, that's good, 'cause neither did I :)
>  >
>  >     Kirk
>  >
>  > Lifoo wrote:
>  >
>  > > Does anyone know of a shell of prog that removes the 12k CAPof progs.
>  > > There are many games for the 85 and 83 that won't run on the 86 because
>  > > they are too large.  If there isn't a prog like that.  Then I think
that
>  > > that would be a good idea.
>