Forum comments in chronological order

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Dec 2017

Massively Interleaved Sprite Crunch

Anonymous
Fri 1-Dec-2017 05:03
If your crunched sprite starts at offset 0x35 what do you do to get there to begin with? Do you start at 0 with the FG color set to black or in the top border and do some dummy crunch to traverse the graph to the right starting point?

Was wondering that myself. I guess that's what he means. Im unsure of the benefit of this though, as opposed to simply changing the sprite definition pointer. The sprite hasnt ended, and loops back... so I guess you can change the def and effectively have the sprite "start again". It's still the same sprite though, as opposed to the 17 pixel sprites that are the minimum.

On another topic, it seems the demo can behave a bit weird with multiple disk drives present on the serial bus (tried with a real 1541 as drive 8 and an Ultimate-II as drive 9)... could it be that you implement some custom serial protocol which the other drive might respond to or something?

Nearly all modern demo loaders have the same issue. They uses the various lines in weird ways, which means the ATTN line (from memory) is getting smashed and confusing other attached drives.

Could possibly be worth enumerating the attached drives at the start and putting all drives except #8 in a hard loop of some kind, but the easier solution is to just turn off all drives except #8 when watching a demo :)

StY1z000r

GCR decoding on the fly

Anonymous
Mon 11-Dec-2017 09:33
Also from my side my best congratulations!!! As a teenager I analysed all the fast loaders that were accessible to me at that time and I understood the tricks they were using on the GCR decoding and the serial transmission stuff. I even wrote a fast loader myself as a hobby (on paper, it never made it into a production state). So I want to say that I highly appreciate all the tricks you came up with - great, great stuff!!!

The TTY demystified

Anonymous
Mon 11-Dec-2017 20:21
@OP, Btw do you have any "to the metal" UNIX/linux books to recommend that has information regarding such stuff?