Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!bionet!agate!saturn!ucscb.UCSC.EDU!alibaba
From: alibaba@ucscb.UCSC.EDU (Alexander M. Rosenberg)
Newsgroups: comp.sys.mac.programmer
Subject: ADB Internals; would DTS get an answer?
Message-ID: <6996@saturn.ucsc.edu>
Date: 2 May 89 07:39:46 GMT
Sender: usenet@saturn.ucsc.edu
Reply-To: alibaba@ucscb.UCSC.EDU (Alexander M. Rosenberg)
Organization: Univ. of California at Santa Cruz Hacker's Anonymous
Lines: 40

Okay, I have a need to perform macroing-like functions (one Mac
will control another.). I want to interfere as little as possible
with the target Mac. I want to feed bogus ADB data to it's service
procedures. This _should_ be completely kosher.

An ADB service proc is set up as follows:

D0 CommandNum
A0 Buffer (pointer)
A1 ServiceProc (pointer)
A2 data Area (pointer)

Okay, so, this is a simple thing. The problem is that some people
(no names, but they work in the ROM group at Apple) decided that the
mouse and keyboard service procs would read the data that is available
through A0 via A3. What's in A3, you might ask? A pointer to the
ADBBase variables. These are found in private.a. 

The reason for calling service procs instead of diddling low memory
globals? The service procs are different for each Mac. Different
low memory globals may exist, and by calling the service procs
directly, I should be able to not have to know how the mouse
driver works.

The problems: 
1) the darn procs Apple supplies use A3 instead of A0.
(they do MOVE.W $164(A3), D1 and such instead of MOVE.W (A0),D1)

2) if no ADB devices are really hooked up to the target Mac, then
how do I obtain pointers to the service procs (especially since
6.0.X patches the mouse proc only if a mouse is connected...)?

Any answers would be appreciated. Especially answers from Apple.

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