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From: carter@Neon.Stanford.EDU (Thomas J. Carter)
Newsgroups: comp.sys.mac.programmer
Subject: alternate screen buffer on Mac II
Summary: is it possible?
Keywords: alternate screen buffer, Mac II, VIA register
Message-ID: <1990Mar13.040203.6874@Neon.Stanford.EDU>
Date: 13 Mar 90 04:02:03 GMT
Organization: Computer Science Department, Stanford University
Lines: 16

I'm trying to speed up some graphics where I've previously used CopyBits().
I want to use the alternate screen buffer and simply switch back and forth
between them.  On the SE I know the location of both screens in memory given
by ScrnBase and ScrnBase - 0x8000 but I'm having trouble finding the alternate
screen buffer on a Mac II with a combination of monitors.  Can this be done?
How?

Also, on the SE I just switch the vPage2 bit in the VIA register back and
forth.  Can I do the same thing on a Mac II?  I read somewhere that that 
bit is reserved but I don't what it is reserved for.  Can someone shed 
a little light here?

Thanks in advance.

Tom Carter
carter@neon.stanford.edu