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From: nparker@cie.uoregon.edu (Neil Parker)
Newsgroups: comp.sys.apple2
Subject: Re: Disk // register listing
Summary: Clarification of machine-language routine parameters
Keywords: I goofed
Message-ID: <1990Nov9.100646.12820@ariel.unm.edu>
Date: 9 Nov 90 10:06:46 GMT
References: <cs4w+@ANDREW.CMU.EDU> <9011030453.AA02428@apple.com> <1990Nov08.105414.22053@scion.CS.ORST.EDU>
Sender: news@ariel.unm.edu (USENET News System)
Reply-To: nparker@cie.uoregon.edu (Neil Parker)
Organization: The Universal Society for the Prevention of Reality
Lines: 27

In article <1990Nov08.105414.22053@scion.CS.ORST.EDU> parkern@jacobs.cs.orst.edu (Neil Parker) writes:
>[lotsa stuff deleted]
>Assuming that the disk motor is on, the following code (lifted from the
>Apple Orchard article) will step from CURTRK to DESTRK on the disk drive
>whose slot number (*16) is stored in SLOT:

I realized after I posted this routine that I failed to state that CURTRK
and DESTRK should contain HALF-TRACK numbers, not TRACK numbers.  To
obtain the half-track number, multiply the track number by two.  For
example,
	LDA CURRENT_TRACK
	ASL
	STA CURTRK
	LDA DEST_TRACK
	ASL
	STA DESTRK

I apologize for any confusion caused by this omission.

          - Neil Parker
--
Neil Parker                 No cute ASCII art...no cute quote...no cute
nparker@cie.uoregon.edu     disclaimer...no deposit, no return...
parker@corona.uoregon.edu   (This space intentionally left blank:           )
parkern@jacobs.cs.orst.edu  (Sorry about the proliferation of net addresses...
the news reader on my usual machine is broken tonight, so I had to use
another machine.)