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TheBF

A Mind is Born C64 Demo

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14 hours ago, TheBF said:

I don't think we could do this in 256 bytes on TMS9900?

Hi BF.

According to what certain programmers have said, there's only about 180 useable Bytes in CPU ram.  Most programmers used CPU RAM to store linked-lists for monsters in games, or the scroll routine for Parsec.  That said, I bet there's some clever Guru out there who could make it do something? 

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If you don't use the console interrupt or most of the ROM utilities, then you can use 224 bytes (assuming 32 bytes are reserved for your 16 registers).

 

The long instruction length is certainly an issue, but I kind of wonder what we COULD pull off in scratchpad. There's 8k of ROM, after all, and 18k of GROM available, if you can find a way to use it... not to mention 16k of VRAM... but if we limit the loader to the 256 bytes of scratchpad...

 

I don't have time to issue the challenge right now. But someday... ;)

 

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It is an interesting challenge for anyone.

I am most fascinated at the moment by the music which is a pretty impressive piece in 64 bars.

We have most of the resources to do something that good. Not sure how we can do the filtration effects with our sound chip. Don't think we can.

We could bit bang wave-forms out the 9901 on the Cassette output port maybe?

 

I re-read the article and see that the melody is just a short sequence of 8 bytes that are mutated with xor and other operations.

Building on Tursi's idea we might be able to extract a cool melody this way from the ROMS or GROMS. Or this could perhaps be an 8 byte sound list that plays but we modify it as it is running. :) 

 

If it has to fit in 256 bytes can we load it as E/A3 so we have VDP utilities?  I think that's fair. :) 

 

 

 

 

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