[Coco] Updated mouse routines?

tim lindner tlindner at macmess.org
Mon May 16 11:38:46 EDT 2016

On Mon, May 16, 2016 at 7:50 AM, Bill Pierce via Coco
<coco at maltedmedia.com> wrote:
> Tim, I guess that would take a full disassembly of CocoMax II or III.

Actually it wouldn't take a full disassembly.

Here is what I would do:

Start MAME with the debugger enabled and set a watch point for $FF60.

In the emulator start CoCo Max II and record where every access of
$FF60 happens.

I am 100% certain there would only be one subroutine that reads the
mouse at $FF60. If there were two or three I would be surprised. More
than that I would think something went wrong with the sampling.

Now you have the address of the routine that reads the mouse and you
would only need to disassemble around that address.

But it turns out someone has already done this. On the
ColorComputerArchive.com website there is a copy of CoCo Max II with
an alternate loader that includes a "Joystick" driver. It's a small
routine that pages in the BASIC ROM, Jumps to [$A00A] to sample the
joysticks, reads the button and passes that information back to CoCo

Now all I have to do if find a place in RAM to put the hi res joystick
routine. It's fairly large and there might not be a place to put it. I
just wanted to see if someone already has done it.

tim lindner

"Proper User Policy apparently means Simon Says."

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