Re: Data Becker CBM-8000 hi-res graphics

From: David Holz <david.holz_at_grindwork.com>
Date: Tue, 5 Sep 2017 07:32:20 -0700
Message-ID: <2ef44a18-3ae9-ab92-0165-a311474949bf@grindwork.com>
By the way, I was looking for text and BASIC tokens, and I don't see
any.  There's actually very little non-asm data at all in the ROM, after
tracing the initial JMP table and the IRQ handler at 97b6.

At 9069, right after the jump table, is this:
https://i.imgur.com/w3cEKmR.png  Given the angle brackets with 2 spaces
after them, it might be some sort of prompt or display.  The code at
9db8 loads 0937/8 with 9069, and I think that's the only reference.  No
clue what the $1b is used for, though.  There's only 1 "xxx #$1b" at
9df0, and it doesn't seem related.

At 9512 is a bit table:  80 40 20 10 08 04 02 01

9cc6 has a potential block/line drawing character table, as mentioned:
https://i.imgur.com/Y58YktM.png  It's used to compare against 03da in a
long chain of tests starting at 99d5

The most curious is at 9d58, which does seem to be some sort of printout
routine with X and Y: https://i.imgur.com/FXIUaDx.png  The only
reference to those addresses seem to be the lda/ldx uses above, so this
might be able to be a useful starting point.

And the most entertaining is the end of the image, where there's some
leftover source code text: https://i.imgur.com/4RO5G48.png :)


Beyond that, there's no other data or text in the ROM image,
unfortunately.  It's all code.


[I don't know if the list supports attached images, or handles Unicode
for the PETSCII conversions, so I just pasted screenshots]



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Received on 2017-09-05 15:00:03

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