Path: utzoo!attcan!uunet!ogicse!ucsd!ucbvax!ECN.PURDUE.EDU!eldorado
From: eldorado@ECN.PURDUE.EDU (David D Jansen)
Newsgroups: comp.sys.apple2
Subject: HELP
Message-ID: <9011060523.AA29563@en.ecn.purdue.edu>
Date: 6 Nov 90 05:23:15 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Lines: 18

Keywords: usr, pr#2


Could some one give me some help with writing to ports 1 or 2 in
assembly?  So far all I can do is PR#2, PR#0 and then it will allow me
to store characters in the data registers, 49304 and 49320.  How do I go
about initializing the ports to read/write to them?
Could you tell me about how to use the USR() function?  Where is the
parameter passed from BASIC get stored to access it from assembly?  How
do you return a value from assembly to BASIC?
Is there a book that explains the BASIC ROMs that would stop me from
asking questions like I did above?

Just back for a visit.
_______________________________________________________________________________
Dave Jansen             |  INTERNET:  eldorado@en.ecn.purdue.edu
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