Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!samsung!emory!kd4nc!rbdc!barry
From: barry@rbdc (Barry Newberry)
Newsgroups: comp.sys.apple2
Subject: Playing (rough) with CDA's
Summary: How do I get a CDA count ?
Message-ID: <1990Jul2.062757.2290@rbdc>
Date: 2 Jul 90 06:27:57 GMT
Reply-To: barry@rbdc.UUCP (Barry Newberry)
Distribution: usa
Organization: N.C. Home for Deranged Programmers
Lines: 26

As far as I can tell, you can install CDA's (Toolbox #$0F05), but
you can't remove them (nicely). I can find the pointers to the CDA's
with the Memory Peeker CDA; look for ID #$5001, and that memory block
should contain all of the CDA pointers. (At least this works on my
ROM 01 machine.) Have new Toolbox routines been added to kill unwanted
CDA's ? If not, where can I find the counter for the number of CDA's ?
(Apparently, you can _GetNumNDAs_ (#$1B05), but you can't get the number
of CDA's.) I want a GUARANTEED method for finding the CDA count, as
opposed to something that "just-happens-to-work."
     I am heavily into Assembly; I've written a SCC 8530 interrupt
handler using the SCC(chan)REG and SCC(chan)DATA softswitches to do
everything. (It works, but I have no way of knowing if I've taken all
of the proper steps for the Init.) All I need is the Technical Info.
By the way, I'm planning to write a CDA (for ProDOS 8) to act as a
Dumb Terminal. I get a lot of Busy signals from a certain local BBS,
and I'd like to play with BASIC until I can connect. For that matter,
any ProDOS 8 program which doesn't mess with IIgs specific memory
would work with the CDA.


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