Re: Decoding RamFactor's memory detection

[BLuRry <brendan.robert@gmail.com>]

Turns out that there is a ram size detection routine in the diagnostic rom code and also the MLI (actually, I think that the diagnostic uses the MLI to get the size.)  It must be purely based on a "Store stuff and see what sticks" approach to detection, because there are ZERO places in the ROM that change.

RamFactor emulation in Jace is 100%.  I was able to run the AppleWorks expander without issue and when you change the ram size, up to 16megs show up.  Just like the real deal, only weighs a lot less. ;-)

Once I have some other code changes worked out (not related to RamFactor) I will post another build.

On Monday, August 20, 2012 7:29:29 PM UTC-5, (unknown) wrote:
> On Thursday, August 16, 2012 10:34:21 AM UTC-6, Hot Rod wrote:
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> > On Thursday, August 16, 2012 11:17:32 AM UTC-5, BLuRry wrote:
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> > > So that means there IS no ram size detection?  That's just bonkers!
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> > That's a bit more difficult to say; those SBC ops are against (presumably) some memory locations ($CBDE,X; $CBE3,X), which condition the carry bit.  Those could be the tests, but not enough context to tell.
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> > But the code snippet provided has some funny addressing - it seems to be ascending, but then jumps backwards, skips ahead? Not sure what to make of that.
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> I don't think there needs to be a RAM size detection in the Ramfactor ROM, since there is a separate system file on disk that does both a diagnostics and RAM size of the card
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> Rob