[Coco] disable super extended basic

Jason M oleribus at gmail.com
Fri Jan 29 11:45:56 EST 2016


Along these same lines, what else could be cleared out to make the most
room for game program and data ?

I came across this nobasic.c program (
http://perso.b2b2c.ca/sarrazip/dev/nobasic.c) which made me start to wonder
what else could go ...

I'm planning to use high res graphics so I know i need those 4 8k pages -
and I think I ready there are some things in the top end of of memory that
are necessary - is everything else fair game ?

thanks,
JasonM





On Thu, Jan 28, 2016 at 1:47 PM, William Astle <lost at l-w.ca> wrote:

> On 2016-01-28 10:09, Robert Hermanek wrote:
>
>> Is it possible to "disable" super extended basic on a coco3?  If I
>> understand the boot process correctly, the original unmodified basic and
>> extended basic code is in ROM, and the boot process automatically
>> executes the "super" extended basic code in the $E000+ range, and this
>> code "patches" the originally loaded extended basic ROM image to
>> integrate the super extended functionality.
>>
>> Well ok.  But I was thinking the other day it would be nice to have
>> basic, and extended basic, and HDB-DOS (in my case) all loaded up as per
>> normal, but then detach super-extended basic and get it out of there...
>> it would be nice to be able to build my own ML code that does clever
>> things with the coco3 hardware, while leaving the basic interpreter
>> intact.... and if I'm not using super extended basic commands, the $E000
>> memory page would be a great place to put it.
>>
>
> As long as you are not using any SECB features, you can disable SECB.
>
> There are two easy ways to do it. First, you can simply drop into ROM
> mode. However, that means you can't use the upper 32K of RAM in the machine
> since accessing that would access the ROM.
>
> Alternatively, you can do a simple ROM/RAM copy, the same as you would do
> on a 64K coco2. That will copy the ROMs over *without* the fancy patching
> and other gimmicks done at startup. Doing it this way would mean you have
> no problems with RAM access and can actually use the upper 8K of RAM for
> some purpose. (24K would be used for the ROM copies.)
>
>
>
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