[Coco] CoCo 3 MMU test for all

Guillaume Major gmajor at videotron.ca
Sun Jan 20 09:42:02 EST 2008

Hi Roger,

It gives 121 on my Coco 3 with a 512K SIMM upgrade from Cloud-9.


"Roger Taylor" <operator at coco3.com> wrote in 
message news:20080120143114.5D2A87D117 at qs281.pair.com...
> Dudes and dudettes,
> There's a trick to creating super long LOADM'able programs on a CoCo 3 but 
> it relies on every CoCo 3 giving the same results of the following test:
> At the stock WIDTH 32 prompt, type:
> ?PEEK(65441)
> Won't you please type the above command on your real CoCo 3 only (not an 
> emulator), and post the results here?
> It *should* hopefully yield 57 which is an MMU block #, ofcourse.  If it 
> gives a reading of 11xxxxxx where the high two bits are set (or either of 
> the 2 high bits) then a separate special LOADMable program would have to 
> be created for that CoCo variation.  I could perhaps try to LOADM a patch 
> right into Disk BASIC that would ignore bad readbacks while loading, but 
> with all the types of DOSes out there, I doubt I will take that route. 
> The upper 2 bit statuses also might depend on the memory upgrade 
> installed, etc.
> I have already created a test copy of Jeweled which LOADMs the 32k 
> backdrop graphics into MMU 48-51 before loading the program itself.
> This is nothing new, but it *is* 2008 and my way of thinking is not like 
> it was in 1985 or even 2005.  In a 512k CoCo 3 using the extended LOADM 
> trick, huge extraordinary-for-a-CoCo 3 games with HQ sound effects and 
> dithered graphics could be loaded in up to the size of a floppy disk, 
> ofcourse.  A 128k-size .bin file containing the entire game contents? 
> I'll soon see.
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