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From: stc7@cunixb.cc.columbia.edu (Steven T Chiang)
Newsgroups: comp.sys.apple2
Subject: Re: Stellar 7 re-release
Message-ID: <1991Jan5.075404.3893@cunixf.cc.columbia.edu>
Date: 5 Jan 91 07:54:04 GMT
References: <m0imLGQ-0000DQC@jartel.info.com> <60237@microsoft.UUCP>
Sender: news@cunixf.cc.columbia.edu (The Daily News)
Organization: Columbia University
Lines: 20

>I think that you are overlooking a detail in the design of the GS.
>Multiple palettes are enabled by setting an interrupt bit for
>individual scan lines.  This interrupt does, in fact, take CPU time
>to handle, as all 16 color registers must be loaded for the new
>palette.  Just because all of this is set up by the system and not by
>your own code does not mean that it is totally free.  There is a CPU
>time price.  Moving from 320X200 with 16 colors to 320X200 with 256
>colors takes CPU time.

	That's not true, I think you are thinking of scan line
interrupt mode.  The actual GSSHR video memory has space for 16
different palettes.  One nibble of the SCB points to one of the
sixteen palettes.  Thus, you don't have to swap palettes in and out.

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