barry@rbdc (Barry Newberry) (07/02/90)
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.
--
------------------------------------------------------------------------
Remember, until there is a cure for Assembly Language Brain Fry,
there will always be the N.C. Home for Deranged Programmers.
.......................................................................dlyons@Apple.COM (David A. Lyons) (07/03/90)
In article <1990Jul2.062757.2290@rbdc> barry@rbdc.UUCP (Barry Newberry) writes: >As far as I can tell, you can install CDA's (Toolbox #$0F05), but >you can't remove them (nicely). This is mostly correct. You *can* remove them, with RemoveNDA and RemoveCDA, added for System Software 5.0. The thing is you have to know the right Handle to pass to those calls, and the system provides no way to get the handles. The only reliable way is to remove only DAs that your program installed itself & recorded the handles somewhere (say, in the MessageCenter). > [...] where can I find the [guaranteed] counter for the number of CDA's ? There's no guaranteed way. >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. I don't know if it will answer all your questions, but check out GS Technical Note #18 by Jim Luther ("Do-It-Yourself SCC Access"). The revision I have here (at home) is March 90. Not sure if it was revised in May, but it is being revised for July. -- David A. Lyons, Apple Computer, Inc. | DAL Systems Apple II Developer Technical Support | P.O. Box 875 America Online: Dave Lyons | Cupertino, CA 95015-0875 GEnie: D.LYONS2 or DAVE.LYONS CompuServe: 72177,3233 Internet/BITNET: dlyons@apple.com UUCP: ...!ames!apple!dlyons My opinions are my own, not Apple's.