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How do I know if a binary image larger than 8k was served as inverted bank switching?


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You try it, sadly.

That said, if the filename ends with 8.bin or 9.bin, that is an indicator. 8 is non-inverted, 9 is inverted.

If it's anything else, it is /probably/ non-inverted but there's no real way to tell.

 

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Also note that @Asmusr made a really nice bank inversion tool that can switch a cartridge file between the two formats--and it works both ways, so inverted files are converted to non-inverted, and non-inverted can be converted to inverted. All you do is identify the file to be converted and specify the new output name. Super easy to use.

bankinvert.zip

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20 hours ago, Stuart said:

Would @Asmusr be willing to share how his bank invert program works? Does it search for bytes for a MOV instruction to >600x and swap the destination address?

Yeah, it's not intelligent, it just inverts the order. If you don't know what you started with, then you won't know what you ended with ;)

 

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The conversion can be dumb like this because we don't change the code to select a bank. We just arrange the banks in the order that the cartridge latch would output. If bank 0 is selected an inverting latch provides 11111111 as the bank select high address signals to the EPROM (or whatever) .  If bank 0 is selected in a cartridge with a non-inverting latch, then the bank select address signals get 00000000. (assuming only an 8-bit latch)

 

Either way we still write machine instructions that use the same write to address 6000 + ( bank << 1) to latch the logical bank number.

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