Q: control is a C&T 65550?

Michel Lanners mlan at cpu.lu
Fri Jun 11 15:43:15 EST 1999

On  10 Jun, this message from Daniel Jacobowitz echoed through cyberspace:
[snip'ed the details]
> I intend to see what I can do about documenting the hardware cursor. 
> With all the excellent advice I've gotten, I expect it won't be too
> difficult.

One thing I have done to look at hoe this stuff is working is to put
the cursor under Macos and/or MacsBug at some precise location (top
left corner), and look at the data in the invisible last portion of
each scanline in VRAM. That should tell us how and in what format the
cursor bitmap needs to be drawn. Restricting the cursor movement to
horizontal movements, and looking at RaDaCal's registers, should tell
us where the horizontal position needs to be set.

Unfortunately, as to the registers that control the appearance of the
cursor (visible/not visible; its colors, etc...), I have no iddea where
exactly on RaDaCal they are, and how to identify them except by poking
at registers from a distance...

>> Obviously, all of the above information can be totally wrong ;-). If
>> there is any Apple engineer in the audience who knows better, please do
>> speak up!
> Unfortunately, the Apple engineers in the audience aren't allowed to :(

What a shame! After all, the control hardware can be seen as a legacy
device, being surpassed by any and all current video chips... or might
Apple be hiding some really cool and powerful feature deep inside
control? I doubt it....


Michel Lanners                 |  " Read Philosophy.  Study Art.
23, Rue Paul Henkes            |    Ask Questions.  Make Mistakes.
L-1710 Luxembourg              |
email   mlan at cpu.lu            |
http://www.cpu.lu/~mlan        |                     Learn Always. "

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