[Coco] CoCo 3 MMU test for all

[Diego Barizo]

I just tried with a '86 GIME and 128 Kb, also getting 121.

Diego



Joel Ewy wrote:

> Roger Taylor wrote:

>   

>> 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 get 121 here on a CoCo 3 with a Tandy 512K upgrade.  I think that on a

> stock CoCo the memory is mapped into the upper range and mirrored

> throughout the lower addresses.  If you are using an emulator (which

> usually supports up to 2M) things may be different.

> 1.  My CoCo 3 service manual says those registers are "Write Only".  Do

> they mean that in the same sense as "No User Serviceable Parts Inside"?  :)

>

> 2.  I have a 1986 GIME chip laying around.  Should I pop that in and see

> if it's any different?

>

> JCE

>   

>> 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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>>     

>

>

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